MIC CA Flashcards
How does varicella-zoster virus present clinically?
A mild prodrome of fever and malaise may occur 1 to 2 days before rash onset, particularly in adults. In children, the rash is often the first sign of disease.
Incubation period for varicella
14 to 16 days after exposure to a varicella or a herpes zoster rash, with a range of 10 to 21 days.
Varicella in Unvaccinated Persons presentation
The rash is generalized and pruritic. It progresses rapidly from macular to papular to vesicular lesions before crusting.
Lesions are typically present in all stages of development at the same time. The rash usually appears first on the chest, back, and face, then spreads over the entire body.
The lesions are usually most concentrated on the chest and back.
Symptoms typically last 4 to 7 days.
- Breakthrough varicella is infection with wild-type varicella-zoster virus (VZV) occurring in a vaccinated person more than _____________ days after varicella vaccination.
- Varicella in Vaccinated Persons (Breakthrough Varicella) presentation
- More than 42 days after varicella vaccination.
- Breakthrough varicella is usually mild. Patients typically are afebrile or have low fever and develop fewer than 50 skin lesions. They usually have a shorter illness compared to unvaccinated people who get varicella. The rash is more likely to be predominantly maculopapular rather than vesicular.
Since the clinical features of breakthrough varicella are often mild, it can be difficult to make a diagnosis on clinical presentation alone.
Laboratory testing is increasingly important for confirming varicella and appropriately managing the patients and their contacts.
Breakthrough varicella occurs less frequently among those who have received two doses of vaccine compared with those who have received only one dose; disease may be even milder among two-dose vaccine recipients, although the information about this is limited.
Transmission of VZV
Varicella is highly contagious. The virus can be spread from person to person by direct contact, inhalation of aerosols from vesicular fluid of skin lesions of acute varicella or zoster, and possibly through infected respiratory secretions that also may be aerosolized. A person with varicella is considered contagious beginning one to two days before rash onset until all the chickenpox lesions have crusted. Vaccinated people may develop lesions that do not crust. These people are considered contagious until no new lesions have appeared for 24 hours.
It takes from 10 to 21 days after exposure to the virus for someone to develop varicella. Based on studies of transmission among household members, about 90% of susceptible close contacts will get varicella after exposure to a person with disease.
People with breakthrough varicella are also contagious. One study of varicella transmission in household settings found that people with mild breakthrough varicella (<50 lesions) who were vaccinated with one dose of varicella vaccine were one-third as contagious as unvaccinated people with varicella. However, people with breakthrough varicella with 50 or more lesions were just as contagious as unvaccinated people with the disease.
Varicella is less contagious than measles, but more contagious than mumps and rubella.
Complications of VZV
The most common complications from varicella are:
In children: Bacterial infections of the skin and soft tissues
In adults: Pneumonia
Severe complications caused by the virus include cerebellar ataxia, encephalitis, viral pneumonia, and hemorrhagic conditions.
Other severe complications are due to bacterial infections and include:
- Septicemia
- Toxic shock syndrome
- Necrotizing fasciitis
- Osteomyelitis
- Bacterial pneumonia
- Septic arthritis
Pregnant women who get varicella are at risk for serious complications, primarily pneumonia, and in some cases, may die as a result of varicella.
Some studies have suggested that both the frequency and severity of VZV pneumonia are higher when varicella is acquired during the third trimester, although other studies have not supported this observation.
Consequences on foetus/ baby if infected during pregnancy VZV
If a pregnant woman gets varicella in her first or early second trimester, her baby has a small risk (0.4 to 2.0%) of being born with congenital varicella syndrome. The baby may have scarring on the skin; abnormalities in limbs, brain, and eyes, and low birth weight.
If a woman develops varicella rash from 5 days before to 2 days after delivery, the newborn will be at risk for neonatal varicella. Historically, the mortality rate for neonatal varicella was reported to be about 30%, but the availability of VZV immune globulin and intensive supportive care have reduced the mortality to about 7%.
Managing People at High Risk for Severe Varicella
(YES) For people exposed to varicella or herpes zoster who cannot receive varicella vaccine, varicella-zoster immune globulin can prevent varicella from developing or lessen the severity of the disease.
Varicella-zoster immune globulin is recommended for people who cannot receive the vaccine and 1) who lack evidence of immunity to varicella, 2) whose exposure is likely to result in infection, and 3) are at high risk for severe varicella.
The American Academy of Pediatrics (AAP) recommends that certain groups at increased risk for moderate to severe varicella be considered for oral acyclovir or valacyclovir treatment. These high risk groups include:
Healthy people older than 12 years of age
People with chronic cutaneous or pulmonary disorders
People receiving long-term salicylate therapy
People receiving short, intermittent, or aerosolized courses of corticosteroids
Some healthcare providers may elect to use oral acyclovir or valacyclovir for secondary cases within a household. For maximum benefit, oral acyclovir or valacyclovir therapy should be given within the first 24 hours after the varicella rash starts.
Intravenous acyclovir therapy is recommended for severe disease (e.g., disseminated VZV such as pneumonia, encephalitis, thrombocytopenia, severe hepatitis) and for varicella in immunocompromised patients (including patients being treated with high-dose corticosteroid therapy for >14 days).
Famciclovir is available for treatment of VZV infections in adults, but its efficacy and safety have not been established for children. In cases of infections caused by acyclovir-resistant VZV strains, which usually occur in immunocompromised people, Foscarnet should be used to treat the VZV infection, but consultation with an infectious disease specialist is recommended.
Availability of vaccine VZV
(YES) Two doses of varicella vaccine are recommended for all children, adolescents, and adults without evidence of immunity to varicella. Those who previously received one dose of varicella vaccine should receive their second dose for best protection against the disease.
How does HFMD virus present clinically?
Incubation period is 3–6 days, and illness usually is self-limited, with recovery within 7–10 days.
Patients usually present with fever and malaise; then sore throat and painful vesicles (herpangina) appear in the mouth, involving the buccal mucosa, tongue, or hard palate, and a peripheral rash, usually papulovesicular, appears on the hands (palms), feet (soles), or less often on the buttocks, genitals, elbows, and knees.
In rare cases, patients can develop brainstem encephalitis, aseptic meningitis, myocarditis, or pulmonary edema and can die from complications.
Additionally, HFMD can have an atypical presentation, often in adults, beginning with a rash or lesion that enlarges and coalesces to form bullae; a thorough travel history or history of recent exposure to others with the infection is critical to making the diagnosis. Onychomadesis (shedding of the nails) and desquamation of the palms or soles can occur during convalescence
Transmission of VZV
Transmission occurs by direct person-to-person contact with the saliva, nose and throat secretions, vesicle fluid, or stool of an infected person and through contact with contaminated surfaces and objects (e.g., common diapering areas, shared toys, eating utensils).
Vaccine for HFMD
There is no vaccine in the United States to protect against the viruses that cause HFMD. Researchers are working to develop vaccines to help prevent HFMD in the future.
How does measles virus present clinically?
easles is an acute viral respiratory illness. It is characterized by a prodrome of fever (as high as 105°F) and malaise, cough, coryza, and conjunctivitis -the three “C”s -, a pathognomonic enanthema (Koplik spots) followed by a maculopapular rash.
The rash usually appears about 14 days after a person is exposed. The rash spreads from the head to the trunk to the lower extremities.
Patients are considered to be contagious from 4 days before to 4 days after the rash appears. Of note, sometimes immunocompromised patients do not develop the rash.
Complications of measles
Common complications from measles include otitis media, bronchopneumonia, laryngotracheobronchitis, and diarrhea.
Even in previously healthy children, measles can cause serious illness requiring hospitalization.
One out of every 1,000 measles cases will develop acute encephalitis, which often results in permanent brain damage.
One to three out of every 1,000 children who become infected with measles will die from respiratory and neurologic complications.
Subacute sclerosing panencephalitis (SSPE) is a rare, but fatal degenerative disease of the central nervous system characterized by behavioral and intellectual deterioration and seizures that generally develop 7 to 10 years after measles infection.
Transmission of measles
Measles is one of the most contagious of all infectious diseases; up to 9 out of 10 susceptible persons with close contact to a measles patient will develop measles.
The virus is transmitted by direct contact with infectious droplets or by airborne spread when an infected person breathes, coughs, or sneezes. Measles virus can remain infectious in the air for up to two hours after an infected person leaves an area.
Vaccination measles
Yes
Measles can be prevented with measles-containing vaccine, which is primarily administered as the combination measles-mumps-rubella (MMR) vaccine.
The combination measles-mumps-rubella-varicella (MMRV) vaccine can be used for children aged 12 months through 12 years for protection against measles, mumps, rubella and varicella. Single-antigen measles vaccine is not available.
One dose of MMR vaccine is approximately 93% effective at preventing measles; two doses are approximately 97% effective. Almost everyone who does not respond to the measles component of the first dose of MMR vaccine at age 12 months or older will respond to the second dose. Therefore, the second dose of MMR is administered to address primary vaccine failure
Treatment for measles
No.
There is no specific antiviral therapy for measles. Medical care is supportive and to help relieve symptoms and address complications such as bacterial infections.
Severe measles cases among children, such as those who are hospitalized, should be treated with vitamin A. Vitamin A should be administered immediately on diagnosis and repeated the next day.
How does mumps virus present clinically?
Mumps usually involves pain, tenderness, and swelling in one or both parotid salivary glands (cheek and jaw area). Swelling usually peaks in 1 to 3 days and then subsides during the next week. The swollen tissue pushes the angle of the ear up and out. As swelling worsens, the angle of the jawbone below the ear is no longer visible. Often, the jawbone cannot be felt because of swelling of the parotid. One parotid may swell before the other, and in 25% of patients, only one side swells. Other salivary glands (submandibular and sublingual) under the floor of the mouth also may swell but do so less frequently (10%).
Nonspecific prodromal symptoms may precede parotitis by several days, including low-grade fever which may last 3 to 4 days, myalgia, anorexia, malaise, and headache. Parotitis usually lasts on average 5 days and most cases resolve after 10 days. Mumps infection may also present only with nonspecific or primarily respiratory symptoms, or may be asymptomatic. Reinfection after natural infection and recurrent parotitis, when parotitis on one side resolves but is followed weeks to months later by parotitis on the other side, can also occur in mumps patients.
Standard precautions are the ________________________. Standard precautions are meant to reduce the risk of transmission of ___________________ and other pathogens from both recognised and unrecognised sources and are to be used, as a _____________, in the care of _______ patients.
blood-borne , minimum, all
5 moments of hand hygiene
1)
2)
3)
4)
5)
1) Before a touching a patient
2) Before clean/aseptic techniques
3) After body fluid exposure risk
4) After touching a patient
5) After touching patient’s surrounding
Handling of linen
Normal soiled linen
Green, canvas
Grossly bood-contaminated linen
Orange
Linen from SARS, COVID-19, cholera, typhoid cases
Red and orange
Red water soluble bad MUST be double-bagged in orange bag
Transmission-based precautions are the ________________________. To be used in addition to __________________.
second-tier of basic infection control. Standard precautions
Contact precaution
single bed, cohort cubicle
MRSA, VRE, CDIFF, CP-CRE, MDR A.BAUMANII
- Hand hygiene
- Wear gloves
- Wear long-sleeved gown for substantial contact with the patient
- Use dedicated equipment or disinfect it before using on another patient
Droplet precaution
single bed
Influenza, Mumps, Rubella, Invasive Neisseiria Meningitis
- Perform hand hygiene
- Wear surgical mask within 1 metre of the patient
- Wear protective eyewear if anticipating splashes to eyes/face
Airbone precautions
SIngle, negative pressure room
Measles, Chicken pox, PTB
- Perform hand hygiene
- Wear an N95 mask
- Keep the door closed at all times
n95 is not required if you are immune to chickenpox, shingles (zoster) or measles through past infection or vaccination.
Protective isolation
Single bed, positive pressure room
Severely immunocompromised host
Staff and visitors with communicable diseases (including respiratory tract infections) should NOT enter
Full precautions
Single bed, negative pressure
HCID (Eg., EVD)
- Perform hand hygiene
- Wear a long-sleeved gown
- Wear an N95 mask
- Use protective eyewear
- Wear gloves
- Use dedicated equipment or disinfect it before using on another patient
Mumps (transmission)
The mumps virus replicates in the upper respiratory tract and is transmitted person to person through direct contact with saliva or respiratory droplets of a person infected with mumps. The risk of spreading the virus increases the longer and the closer the contact a person has with someone who has mumps. The infectious period is considered from 2 days before to 5 days after parotitis onset, although virus has been isolated from saliva as early as 7 days prior to and up to 9 days after parotitis onset. Mumps virus has also been isolated up to 14 days in urine and semen.
When a person is ill with mumps, they should avoid contact with others from the time of diagnosis until 5 days after the onset of parotitis by staying home from work or school and staying in a separate room if possible.
Complications of mumps
Mumps complications include orchitis, oophoritis, mastitis, meningitis, encephalitis, pancreatitis, and hearing loss. Complications can occur in the absence of parotitis and occur less frequently in vaccinated patients. Some complications of mumps are known to occur more frequently among adults than children.
Orchitis occurs in approximately 30% of unvaccinated and 6% of vaccinated post-pubertal male mumps patients. In 60% to 83% of males with mumps orchitis, only one testis is affected. Mumps orchitis has not been linked to infertility, but may result in testicular atrophy and hypofertility. Among adolescent and adult female mumps patients in the United States in the post-vaccine era, rates of oophoritis and mastitis have been ≤1%. However, these complications may be more difficult to recognize and are likely underreported. Pancreatitis, deafness, meningitis, and encephalitis have been reported in less than 1% of cases in recent U.S. outbreaks. Cases of nephritis and myocarditis and other sequelae, including paralysis, seizures, cranial nerve palsies, and hydrocephalus, in mumps patients have been reported but are very rare. Death from mumps is exceedingly rare. There have been no mumps-related deaths reported in the United States during recent mumps outbreaks.
Mumps (pregnancy)
Mumps that occurs in pregnant women is generally benign and not more severe than in women who are not pregnant. Like other infections, there is a theoretical risk that mumps during the early months of pregnancy may cause complications.
Most studies on the effects of gestational mumps on the fetus were conducted in the 1950s–60s when the disease was more common before mumps vaccine was available. One study from 1966 reported an association between mumps infection during the first trimester of pregnancy and an increase in the rate of spontaneous abortion or intrauterine fetal death1, but this result has not been observed in other studies2. One study of low birth weight in relation to mumps during pregnancy found no significant association1. While there are case reports of congenital malformations in infants born to mothers who had mumps during pregnancy, the only prospective, controlled study found rates of malformations were similar between mothers who had mumps and those who did not have mumps during pregnancy
Any vaccine available for mumps?
Vaccination is the best way to prevent mumps and mumps complications. This vaccine is included in the combination measles-mumps-rubella (MMR) and measles-mumps-rubella-varicella (MMRV) vaccines. Two doses of mumps vaccine are 88% (range 32% to 95%) effective at preventing the disease; one dose is 78% (range 49% to 91%) effective.
Any treatment available for mumps
No
Rubella clinical presentation
Rubella is a viral illness that can lead to complications and death. It is characterized by a mild, maculopapular rash along with lymphadenopathy, and a slight fever. The rash usually starts on the face, becomes generalized within 24 hours, and lasts a median of 3 days; it occurs in 50% to 80% of infected people, Lymphadenopathy, which may precede rash, often involves posterior auricular or suboccipital lymph nodes, can be generalized, and lasts between 5 and 8 days. About 25% to 50% of infections are asymptomatic.
Clinical diagnosis of rubella virus is unreliable and should not be considered in assessing immune status. Up to half of all infections may be subclinical or unapparent. Many rubella infections are not recognized because the rash resembles many other rash illnesses.
Transmission of rubella
Rubella is transmitted primarily through direct or droplet contact from nasopharyngeal secretions. Humans are the only natural hosts. In temperate climates, infections usually occur during late winter and early spring.
The average incubation period of rubella virus is 17 days, with a range of 12 to 23 days. People infected with rubella are most contagious when the rash is erupting, but they can be contagious from 7 days before to 7 days after the rash appears.
Complication of rubella
Arthralgia or arthritis may occur in up to 70% of adult women with rubella. Rare complications include thrombocytopenic purpura and encephalitis.
Consequence on foetus (rubella)
When rubella infection occurs during pregnancy, especially during the first trimester, serious consequences can result. These include miscarriages, fetal deaths/stillbirths, and severe birth defects known as CRS. The most common congenital defects are cataracts, heart defects, and hearing impairment.
Vaccination for rubella
ubella can be prevented with rubella-containing vaccine, which is primarily administered as the combination measles-mumps-rubella (MMR) vaccine. The combination measles-mumps-rubella-varicella (MMRV) vaccine can be used for children aged 12 months through 12 years for protection against measles, mumps, rubella and varicella. Single-antigen rubella vaccine is not available.
One dose of MMR vaccine is about 97% effective at preventing rubella if exposed to the virus.
Treatment for rubella
here is no specific antiviral therapy for rubella infection.
Healthcare providers should:
Consider rubella in unvaccinated patients with febrile rash illness and other rubella symptoms, especially if the person recently traveled internationally or was exposed to a person with a confirmed rubella case.
Promptly isolate people suspected to have rubella and report them to the local health department
Collect nasopharyngeal swabs, throat swabs, or urine specimens for viral detection by polymerase chain reaction (PCR) testing and molecular typing, and blood for serology testing.
Common cold clinical presentation
Many people will have no symptoms. Among those who develop symptoms, they typically last about 7 days but can last up to two weeks. Symptoms may include:
Cough
Sneeze
Runny Nose
Nasal congestion
Sore throat
Headache
Body Aches
Fever
Transmission of common cold
Rhinoviruses are spread through respiratory droplets that are released when an infected person coughs or sneezes. These droplets can enter another person’s body if they breathe them in, or if they touch a surface contaminated with the virus and then touch their eyes, nose, or mouth. Rhinoviruses can also be spread through close personal contact with an infected person, such as shaking hands or hugging.
Complications of common cold
More severe illness is less common but can include asthma exacerbations, bronchioliti middle ear infections, sinusitis, bronchitis, or pneumonia. These symptoms can mirror other respiratory infections.
Any treatment/ vaccine for common cold?
There is no vaccine, treatment, or medication to prevent or cure rhinoviruses. You should take the following actions:
Drink plenty of fluids
Get plenty of rest
Clinical presentation of Covid-19
People with COVID-19 may be asymptomatic or may commonly experience one or more of the following symptoms:
Fever or chills
Cough
Shortness of breath or difficulty breathing
Fatigue
Myalgia (Muscle or body aches)
Headache
New loss of taste or smell
Sore throat
Congestion or runny nose
Nausea or vomiting
Diarrhea
The clinical presentation of COVID-19 ranges from asymptomatic to severe illness, and COVID-19 symptoms may change over the course of illness.
COVID-19 symptoms can be difficult to differentiate from and can overlap with other viral respiratory illnesses such as influenza(flu) and respiratory syncytial virus (RSV). Because symptoms may progress quickly, close follow-up is needed, especially for:
older adults
people with disabilities
people with immunocompromising conditions, and
people with medical conditions that place them at greater risk for severe illness or death.T
Transmission. (COVID 19)
Droplet precaution
People infected with SARS-CoV-2 can transmit the virus even if they are asymptomatic or presymptomatic.
Peak transmissibility appears to occur early during the infectious period (prior to symptom onset until a few days after), but infected persons can shed infectious virus up to 10 days following infection.(22) Both vaccinated and unvaccinated people can transmit SARS-CoV-2.
Any treatment available for COVID 19?
Yes
Complications of COVID-19
Clinical treatment recommendations for people with severe to critical COVID-19 are based on the severity of illness. Management often includes care of complications of severe illness, including:
hypoxemic respiratory failure/ARDS,
sepsis and septic shock,
elevation in inflammatory cytokines,
and complications from prolonged hospitalization, including thromboembolism, hospital-acquired pneumonia, and hospital-acquired bacterial and fungal infections.
Additionally, patients with COVID-19 may experience an exacerbation of underlying comorbidities or new onset of cardiac, endocrine, hepatic, renal, gastrointestinal, or central nervous system disease.
Consequence on foetus COVID 19
Pregnant people with COVID-19 (compared to pregnant people without COVID-19) are at increased risk of preterm birth and stillbirth and might be at increased risk of pregnancy complications, including pre-eclampsia.
Influenza clinical presentation
Flu Symptoms
Influenza (flu) can cause mild to severe illness, and at times can lead to death. Flu symptoms usually come on suddenly. People who have flu often feel some or all of these symptoms:
fever or feeling feverish/chills
cough
sore throat
runny or stuffy nose
muscle or body aches
headaches
fatigue (tiredness)
some people may have vomiting and diarrhea, though this is more common in children than adults.
*It’s important to note that not everyone with flu will have a fever
Transmission of influenza
Most experts believe that flu viruses spread mainly by tiny droplets (respiratory droptlets) made when people with flu cough, sneeze, or talk. These droplets can land in the mouths or noses of people who are nearby. Less often, a person might get flu by touching a surface or object that has flu virus on it and then touching their own mouth, nose or possibly their eyes.
Complications of influenza
Complications of flu can include bacterial pneumonia, ear infections, sinus infections and worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes.
Treatment available for influenza?
There are flu antiviral drugs that can be used to treat flu illness.
Flu illness can be more severe for certain people. True or false?
True
Certain groups of people are at a higher risk of developing serious flu complications. These groups of people include children younger than 5 years old, adults 65 years old or older, pregnant people, and people with certain chronic health conditions.
Vaccine available for Flu?
Yes.
CLinical presentation of respiratory syncytial virus infection
People infected with RSV usually show symptoms within 4 to 6 days after getting infected. Symptoms of RSV infection usually include
Runny nose
Decrease in appetite
Coughing
Sneezing
Fever
Wheezing
These symptoms usually appear in stages and not all at once. In very young infants with RSV, the only symptoms may be irritability, decreased activity, and breathing difficulties.
Adults who get infected with RSV usually have mild or no symptoms. Symptoms are usually consistent with an upper respiratory tract infection, which can include rhinorrhea, pharyngitis, cough, headache, fatigue, and fever. Disease usually lasts less than 5 days.
Some adults, however, may have more severe symptoms consistent with a lower respiratory tract infection, such as pneumonia. Epidemiologic evidence indicates that people 60 and older who are at highest risk of severe RSV disease include those with any of the following chronic conditions:
Lung disease (such as chronic obstructive pulmonary disease [COPD] and asthma)
Chronic cardiovascular diseases (such as congestive heart failure and coronary artery disease)
Diabetes mellitus
Neurologic conditions
Kidney disorders
Liver disorders
Hematologic disorders
Immune compromise
Other underlying conditions that a healthcare provider determines might increase the risk for severe respiratory disease
Other underlying factors that the provider determines might increase the risk of severe RSV-associated respiratory illness may include the following:
Frailty
Advanced age
Residence in a nursing home or other long-term care facility
Other underlying factors that a healthcare provider determines might increase the risk for severe respiratory disease
RSV can sometimes also lead to exacerbation of serious conditions such as:
Asthma
Chronic obstructive pulmonary disease (COPD)
Congestive heart failure
Transmission of RSV
RSV can spread when
An infected person coughs or sneezes
You get virus droplets from a cough or sneeze in your eyes, nose, or mouth
You have direct contact with the virus, like kissing the face of a child with RSV
You touch a surface that has the virus on it, like a doorknob, and then touch your face before washing your hands
Vaccines available for RSV?
Yes.
Any treatment for RSV
No. Antiviral medication is not routinely recommended to fight infection. Most RSV infections go away on their own in a week or two. However, RSV can cause severe illness in some people.
CMV
Cytomegalovirus
Clinical presentation of CMV
Most healthy people who acquire cytomegalovirus (CMV) after birth have few symptoms and no long-term health consequences. Some people who acquire CMV infection may experience a mononucleosis-like condition with prolonged fever and hepatitis. Once a person becomes infected, the virus remains latent and may reactivate occasionally. Reactivation of CMV infection rarely causes disease unless the person’s immune system is suppressed due to therapeutic drugs or disease.
For most people, CMV infection is not a serious health problem. However, certain groups are at high risk for serious complications from CMV infection:
Infants infected in utero (congenital CMV infection)
Very low birth weight and premature infants
People with compromised immune systems, such as from organ and bone marrow transplants, and people infected with human immunodeficiency virus (HIV)
Transmission of CMV
CMV is transmitted by direct contact with infectious body fluids, such as urine, saliva, blood, tears, semen, and breast milk. CMV can be transmitted sexually and through transplanted organs and blood transfusions.
CMV can be transmitted to infants through contact with the mother’s genital secretions during delivery or through breast milk.
Any treatment available for CMV?
No treatment is currently indicated for CMV infection in healthy people. Antiviral treatment is used for people with compromised immune systems who have either sight-related or life-threatening illnesses due to CMV infection.
Consequence on foetus CMV
A woman who has a primary CMV infection during pregnancy is more likely to pass CMV to her fetus than a woman who has a subsequent infection during pregnancy.
Infants born <30 weeks gestational age and <1500g who acquire CMV from breast milk may be at risk of developing a late-onset sepsis-like syndrome.
Sign and symptoms of CMV in infants
ost infants with congenital CMV infection never have health problems. About 10% of infants with congenital CMV infection will have health problems at birth, which include:
Rash
Jaundice (yellowing of the skin or whites of the eyes)
Microcephaly (small head)
Low birth weight
Intrauterine growth restriction (low weight)
Hepatosplenomegaly (enlarged liver and spleen)
Seizures
Retinitis (damaged eye retina)
About 40 to 60% of infants born with signs of congenital CMV disease at birth will have long-term health problems, such as:
Hearing loss
Vision loss
Intellectual disability
Microcephaly (small head)
Lack of coordination or weakness
Seizures
Some babies may have hearing loss that may or may not be detected by newborn hearing test.
Treatment of CMV
For infants with signs of congenital CMV disease at birth, antiviral medications, such as ganciclovir or valganciclovir, may improve hearing and developmental outcomes. Ganciclovir can have serious side effects and has only been studied in infants with symptomatic congenital CMV disease.
any vaccines for CMV?
Vaccines are still in the research and development stage.
EBV
Epstein Barr Virus
Clinical presentation of EBV
Symptoms of EBV infection can include
fatigue
fever
inflamed throat
swollen lymph nodes in the neck
enlarged spleen
swollen liver
rash
Transmission of EBV
EBV spreads most commonly through bodily fluids, especially saliva. However, EBV can also spread through blood and semen during sexual contact, blood transfusions, and organ transplantations.
EBV can be spread by using objects, such as a toothbrush or drinking glass, that an infected person recently used. The virus probably survives on an object at least as long as the object remains moist.
The first time you get infected with EBV (primary EBV infection) you can spread the virus for weeks and even before you have symptoms. Once the virus is in your body, it stays there in a latent (inactive) state. If the virus reactivates, you can potentially spread EBV to others no matter how much time has passed since the initial infection.
Any vaccine/ treatment for EBV?
There is no vaccine to protect against EBV infection.
There is no specific treatment for EBV. However, some things can be done to help relieve symptoms, including
drinking fluids to stay hydrated
getting plenty of rest
taking over-the-counter medications for pain and fever
EBV infection can affect a person’s brain, spinal cord, and nerves.
It can cause conditions such as—
EBV infection can affect a person’s brain, spinal cord, and nerves.
It can cause conditions such as—
Viral meningitis (swelling of the tissues that cover the brain and spinal cord)
Encephalitis (swelling of the brain)
Optic neuritis (swelling of the eye nerve)
Transverse myelitis (swelling of the spinal cord)
Facial nerve palsies (paralysis of facial muscles)
Guillain-Barré syndrome (an immune system disease)
Acute cerebellar ataxia (sudden uncoordinated muscle movement)
Hemiplegia (paralysis on one side of the body)
Sleep disorders
Psychoses
EBV infection can affect a person’s blood and bone marrow. The virus can cause the body to produce an excessive number of white blood cells called lymphocytes (lymphocytosis).
EBV can also weaken the immune system, making it more difficult for the body to fight infection.
Examples of some of these conditions include—
Neutropenia with secondary infections
Hemophagocytic syndrome (hemophagocytic lymphohistiocytosis)
Acquired hypogammaglobulinemia
X-linked lymphoproliferative disease
EBV infection can also cause—
Pneumonia (injury of the lungs)
Interstitial lung disease (a large group of disorders, most of which cause scarring of lung tissue)
Pancreatitis (swelling of the pancreas)
Myocarditis (swelling of the heart muscle)
Oral cavity-oral hairy leukoplakia (raised, white patches on the tongue), which is usually seen in people infected with HIV
Cancers associated with EBV infection include—
Burkitt’s lymphoma (cancer of the lymphatic system)
Nasopharyngeal carcinoma (cancer of the upper throat)
Hodgkin’s disease and non-Hodgkin’s lymphoma (cancers of the lymphatic system)
Post-transplant lymphoproliferative disorder (white blood cells are produced in excess)
Other tumors including leiomyosarcomas (cancer in the soft tissue) and T-cell lymphomas
Complications of EBV infection include—
Peritonsillar abscesses (pus-filled tissue near the tonsils)
Acute bacterial sinusitis (bacterial infection of the sinus cavities)
Suppurative lymph nodes (swelling of lymph nodes)
Mastoiditis (bacterial infection of the mastoid bone of the skull)
Sialadenitis (swelling and injury of salivary glands)
Blockage of the air passages in the nose and throat
Zika transmission
Zika virus is transmitted to humans primarily through the bite of an infected Aedes species mosquito.
The mosquito vectors typically breed in domestic water-holding containers; they are aggressive daytime biters and feed both indoors and outdoors near dwellings. Nonhuman and human primates are likely the main reservoirs of the virus, and anthroponotic (human-to-vector-to-human) transmission occurs during outbreaks.
Perinatal, in utero, and possible sexual and transfusion transmission events have also been reported. Zika virus RNA has been identified in asymptomatic blood donors during an ongoing outbreak.
Clinical signs of Zika
Many people infected with Zika virus are asymptomatic. Characteristic clinical findings are acute onset of fever with maculopapular rash, arthralgia, or conjunctivitis. Other commonly reported symptoms include myalgia and headache.
Clinical illness is usually mild with symptoms lasting for several days to a week. Severe disease requiring hospitalization is uncommon and case fatality is low. However, there have been cases of Guillain-Barré syndrome reported in patients following suspected Zika virus infection. Recently, CDC concluded that Zika virus infection during pregnancy is a cause of microcephaly and other severe fetal brain defects.
Treatment/ vaccine for Zika?
No specific antiviral treatment is available for Zika virus disease. Treatment is generally supportive and can include rest, fluids, and use of analgesics and antipyretics.
There is no vaccine to prevent or medicine to treat Zika.
Consequences on foetus (zika)
Zika virus can be passed from a pregnant woman to her fetus.
Infection during pregnancy can cause a birth defect called microcephaly and other severe fetal brain defects
Clinical signs of Dengue
Clinical findings include:
nausea, vomiting, rash, aches and pains, a positive tourniquet test, leukopenia, and the
following warning signs: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleeding, lethargy, restlessness, and liver enlargement.
The presence of a warning sign may predict severe dengue in a patient.
Severe dengue is defined by dengue with any of the following symptoms:
- Severe plasma leakage
leading to Shock (DSS)
Fluid accumulation with respiratory distress - Severe haemorrhage
- Severe organ impairment
- Liver: AST or ALT >=1000
-CNS : Impaired consciousness
-Heart and other organs
Clinical phases of dengue
- Febrile
- Critical phase ( which may lead to Severe dengue)
- Recovery Phase
Febrile phase
typically develop high-grade fever suddenly
fever usually lasts 2–7 days
often accompanied by facial flushing, skin erythema, generalized body
ache, myalgia, arthralgia and headache
anorexia, nausea and vomiting are common
some patients may have sore throat, injected pharynx and conjunctival
injection
can be difficult to distinguish dengue clinically from other infections
clinical features are indistinguishable between severe and non-severe
dengue cases - monitor for warning signs (progression to critical phase)
mild haemorrhagic manifestations like petechiae and mucosal membrane bleeding (e.g. nose and gums) may be seen
positive tourniquet test in this phase increases the probability of dengue
FBC – drop in total white cell count?
Treatment of Dengue
No treatment: No specific antiviral agents exist for dengue.
Availability of vaccine dengue
Dengvaxia is the only dengue vaccine approved by the U.S. Food and Drug Administration and recommended for routine use by the Advisory Committee on Immunization Practices. It is made by Sanofi Pasteur. The vaccine prevents dengue caused by all four dengue virus serotypes.
Transmission of dengue
Dengue viruses are spread to people through the bites of infected Aedes species mosquitoes (Ae. aegypti or Ae. albopictus). These are the same types of mosquitoes that spread Zika and chikungunya viruses.
Rarely, dengue can be spread through blood transfusion, organ transplant, or through a needle stick injury.
From mother to child (Dengue)
Pregnant woman already infected with dengue can pass the virus to her fetus during pregnancy or around the time of birth.
To date, there has been one documented report of dengue spread through breast milk. Because of the benefits of breastfeeding, mothers are encouraged to breastfeed even in areas with risk of dengue.
Importance of pulse pressure in dengue
Importance of pulse pressure :
The patient is considered to have shock if :
- the pulse pressure (i.e. systolic BP - diastolic BP) is ≤20 mm Hg in children
or he/she has signs of : - of poor capillary perfusion (cold extremities, delayed capillary refill, or rapid pulse rate).
- In adults, the pulse pressure of ≤ 20 mmHg may indicate a more severe shock.
Profound shock -> ____________ -> multiple organ failure —-> _______________ —-> massive bleeding
- with thrombocytopenia , hypoxia, acidosis
- advanced disseminated intravascular coagulation
A stepwise approach to the management of dengue
I. Overall assesment
II. Diagnosis, assessment of disease phase and severity
III. Management
Blood tests requested during assessment DENGUE
WCC
Platelet
Baseline
Haematocrit ( HCT)
Complications of severe dengue
Electrolyte imbalance (Hyponatraemia, potassium, calcium)
* Hypo / hyperglycaemia
* Metabolic acidosis
* Fluid overload
* Acute respiratory distress syndrome
* Hospital acquired pneumonia
* Renal failure requiring dialysis
* Liver failure
* Encephalopathy
Diagnostic tests for Dengue
- PCR to look for Dengue virus (send blood in FBC blood tube)
- Serum for POCT (Dengue Duo)
- Serum for Dengue antibody testing
Warning signs of Dengue
- abdominal pain
- persistent vomiting
-clinical fluid accumulation
- mucosal bleeding
- lethargy, restlessness
- liver enlargement > 2cm
- Laboratory : increase in HCT concurrent with decrease in platelet count
Discharge criteria (Clinical)
- No fever for 48 hours
-Improvement in clinical status (general well-being, appetite, haemodynamic status, urine output, no respiratory distress)
Discharge criteria (Laboratory)
Increasing trend of platelet
Stable haematocrit without intravenous fluids
Probable dengue
Live in/ travel to dengue endemic are.
Fever and 2 of the following criteria:
- Nausea, vomiting
- Rash
- Aches and pains
- Tourniquet test positive
- Leukopenia
- Any warning sign
Commensal bacteria
also called “normal flora”
bacteria that are normally found on the human body
usually not harmful
may contribute beneficial effects
Necrotising fasciitis
Beta haemolytic group A strep
Is antibiotic indicated for gastroenteritis?
Usually self limiting-antibiotic not normally indicated
Is antibiotic indicated for enteric feve/ typhoid fever
Unlike gastroenteritis, antibiotic MUST be given
Commonest cause of bacterial pharyngitis
Beta haem group A strep
Complications of bacterial pharyngitis
Rheumatic fever
Glomerulonephritis
(both are immune-mediated, post infection)
Benzlypeniciliin
For strep only
Amoxicillin/ Ampicillin
Like Benzylpen + Enterococcus + Listeria
Cloxacillin
For MSSA and Beta-haem Streptococci only
Ceftriaxone
Does not cover enterococci
For reliable anerobic coverage (both gram positive and negative), use ________________
Metronidazole
What is gram stain
Appearance of bacteria under the microscope
Why purple (gram positive) ?
Thick peptidoglycan
Why pink (gram negative)?
Thin peptidoglycan
Investigation for bacteria
microscopy (gram stain), Culture & Sensitivity (C&S usually takes 3 days to be ready)
Colonisation
presence of bacteria without infection
usually moist, warm body areas
increases in:
hospitalised patients
patients with medical conditions
patients given antibiotics
Investigation for fungus
microscopy (fungal smear), C & S
Investigation for virus
PCR
Investigation for Virus (and some bacteria)
point of care test (POCT)
Investigation for Parasites
microscopy
Investigation for some infections (usually virus + parasites)
serology (antibody testing in blood)
Bacterial or fungal culture report
Result should be interpreted in conjunction with __________________ and ____________
(just because the culture is positive ≠ it’s clinically significant)
contrast this with
_____________________
Positive result usually confirms ______________(eg. COVID PCR result)
Bacterial or fungal culture report
Result should be interpreted in conjunction with clinical presentation
and progress
(just because the culture is positive ≠ it’s clinically significant)
contrast this with
* PCR / POCT
Positive result usually confirms infection (eg. COVID PCR result)
If result is negative or no growth, doesn’t necessarily exclude infection
because :
- Test not sensitive enough (esp. if patient pretreated with antibiotics)
- Test performed too soon / too late after infection
- Poor technique of sampling
- Incorrect test for the infection (eg. Using bacterial swab or ordering
bacterial test when viral infection is suspected)
*poor technique of sampling is also a major cause of result contamination (blood culture sampling, sampling a chronic wound)
Culture
To grown the organism
aerobic culture
anaerobic culture
fungal culture
viral culture
mycobacterial culture
Serology
To detect antibodies present following exposure to the organism
blood test
Molecular testing
detection of nucleic acid (DNA/RNA)
PCR
Microscopy
to see the organisms under the microscope
Gram stain
fungal microscopy
acid-fast stain
When to use Swabs
1) clinical signs of infection
pain, pus, abscess (infected abscess)
2) Symptoms or signs of systemic infection
viral respiratory, nasopharyngeal
3) screening samples
MRSA: nose, axillia, groin
Generally only looks for a specific
organism e.g. MRSA
Screening
Will look for larger number of
pathogenic organisms
aerobic culture
only looks out for anaerobic organisms
anaerobic culture
detects DNA/RNA of organisms
very susceptible to cross-contamination
PCR
differences between Augmentin and Ceftriazone
Augmentin cannot treat CNS infection
Ceftriazone can treat meningitis
Augmentin - IV/oral
Ceftriazone- IM/IV
Spectrum of activity against common bacteria
- Benzylpenicillin - only for strep
- amoxicillin/ampicillin
- augmentin and ceftriazone
- tazocin- covers psuedomonas aeruginosa
- meropenem and imipenem
Vacomycin - pure Gram _____________ coverage only
positive
Ceftazidime- pure Gram _________ coverage only
negative
VRE
vancomycin-resistant enteroccocus
CP-CRE
Carbapenamase Producing Carbapenem-Resistant-Enterobacteriaceae
Cellulitis
Staph aureus
Beta haem Strep A
Community acquired pneumonia
Strep pneumo
Haemophilus influenza
Staph aureus. Clasifically after influenza
Atypical pathogens
1. Chlamadyia pneumoniae, psittaci
2. Mycoplasma pneumoniae
3. Legionella pneumophilia
An important and common gram negative bacillus associated with hospital/healthcare infections
Pseudomonas aeruginosa
Normal sterile body sites
- blood
-Cerebrospinal fluid
-Vitreous fluid
-joint (fluid/tissue)
Common swab type for bacterial culture
Rayon bud (tip) with plastic shaft and amies transport medium
Gel-like Amies media provides…
Provides supportive environment for bacteria and yeast
Rayon bud (tip) with plastic shaft and amies transport medium suitable for
Aerobic culture
Anaerobic culture
Screening (MRSA)
Rayon bud (tip) with plastic shaft and amies transport medium not suitable for
Bacterial PCR
Viral PCR
Viral Culture
Common swab type for Viral Culture and viral PCR
Flocked swab with Univeral Transport Media (UTM)
reddish UTM provides..
provides supportive environment for viruses, chlamydia and mycoplasma
antibiotics to prevent bacterial overgrowth
Flocked swab with Univeral Transport Media (UTM) suitable for
- VIral culture
- viral antigen
- viral pcr
- chlamydial pcr
Flocked swab with Univeral Transport Media (UTM) not suitable for
Bacterial PCR
Aerobic culture
Anaerobic culture
Common swab type for bacterial culture and bacterial PCR
Flocked swab with liquid amies media
Flocked swab with liquid amies media suitable for
- aerobic culture
- anaerobic culture
- Bacterial PCR
- Screening (MRSA)
Flocked swab with liquid amies media not suitable for
- Viral PCR
- VIral culture
Specimen container with formalin only used for
histopathology
formalin is a
tissue preservative which inactivates all bacteria, yeasts and viruses
Specimen container with formalin not suitable for
all microbiology test
Types of urine sample
supra-pubic aspirate
Sterile specimen invasive
Types of urine sample
renal aspirate
Sterile specimen , invasive
Types of urine sample
Catheter urine
often colonized non-invasive
Types of urine sample
mid-stream urine
Clean-catch urine
“clean” but non-sterile specimen, non invasive
Types of urine sample
in-out catheter urine
“clean” but non-sterile specimen procedural
Types of urine sample
- supra-pubic aspirate
- catheter urine
- renal aspirate
- mid-stream urine
- clean catch urine
- in-out catheter urine
Urine collection - catheter specimen urine
Clamp the tubing a few cm distal to the sampling port
Clean the sampling port
Sample from the sampling port.
Aspirate the required amount of urine into the syringe
Inject urine into the specimen pot.
Non-sterile urine sample
catheter urine
mid-stream urine
clean catch urine
in-out catheter urine
Sterile urine sample
supra-pubic aspirate
renal aspirate
Non-culture tests
Blood tests
Microscopy
PCR
Culture tests
Aerobic culture
Viral culture
TB culture
Results turn around time for non culture tests.
Blood tests 1-3 days
Microscopy 1-2 days
PCR 1-3 days
Results turn around time for culture tests.
Aerobic culture 2-5 days
Viral culture 7-21 days
TB culture 10-42 days
UTI is usually associated with _____________________ in _________. There may be associated with ____________________
pyuria (white cells) in urine.
Haematuria
UTI test result
Microscopy:
White cells +++
Red cells ++
Urine dipstick:
Urine esterase ++
Protein++
Blood ++
MBG
Mixed bacterial growth is often an indication of sample contamination
Urine microscopy
Epithelial cells ++
Epithelial cells on urinary microscopy also suggests potential contamination
Types of UTI
- Cystitis ( lower UTI)
- Pyelonephritis (infection of the kidney tissue)
- Catheter associated UTI
Samples to collect for cystitis
Midstream urine culture
Bag urine (children)
Suprapubic urine (children)
Catheter sample (beware positive culture does not always equate to infection, could be colonization)
Samples to collect for pyelonephritis
Midstream urine culture
Bag urine (children)
Suprapubic urine (children)
Catheter sample (beware positive culture does not always equate to infection, could be colonization)
Blood culture- patient usually febrile or septic
Samples to collect for CAUTI
Catheter sample
remember
- urine culture may be polymicrobial: beware positive culture does not always equate to infection, could be colonization
- dipstick/UFEME results become unreliable
Organisms associated with UTI
Gram Negative
- E coli
- Klebsiella pneumonia
- Proteus
- Enterobacter, Citrobacter, Morganella, Serratia
- Pseudomonas aeruginosa
Gram positive
- Enterococcus (less common)
Fungus
- Candida causing UTI (Very, very uncommon - most likely reflects recent antibiotic exposure)
Management for cystitis , CAUTI
if stable and well,
PO abx
short course (3-7 days)
presence pf catheter usually requires min 5 days abx
men require longer course than woman
Management of pyelonephritis/ urosepsis
Start with IV abx
Followed by PO abx if improving after 48 hours
Total abx duration 7-14 days depending on choice of abx
Management of presence of foreign material eg. ureteric, stent , catheter
Remove IF patient persists/ recurs (again ->source control)
Asymptomatic bacteruria
presence of 10tothepowerof5/ml (100, 000 CFU/ML) bacteria in urine culture but patient is asymptomatic
very common in patients > 65 years old
antibiotic should not be given except pregnant woman, patient undergoing urological procedure or surgery
children with repeated UTI
immunocompromised
Kidney transplant patients
Long term abx prophylaxis
Generally not recommended except
- children with recurrent UTI and vesicoureteral reflux with risk of renal scarring
- Patients who are frequently and severely affected by UTI, comparing their quality of life
Hospital acquired pneumonia
Pneumonia which occurs 48 hours or more after hospital admission
Ventilator associated pneumonia
Pneumonia which occurs 48-72 hours after endotracheal intubation
Expected pathogens of CAP
‘typical bacteria’ – Streptococcus pneumoniae, Haemophilus influenzae
‘atypical bacteria’ – Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella
pneumophila
Others – Staphylococcus aureus (esp. post influenza), Klebsiella pneumoniae
Don’t forget about viruses - Influenza
Expected pathogens of HAP
Streptococcus pneumoniae, Haemophilus influenzae
‘coliforms’ aka Enterobacteriaceae/ Enterbacterales
Pseudomonas aeruginosa
Other gram negative bacilli - Acinetobacter
MRSA (if patient is MRSA positive or high prevalence)
Expected pathogens of VAP
Streptococcus pneumoniae, Haemophilus influenzae
‘coliforms’ (gram negative)
Pseudomonas aeruginosa
Other gram negative bacilli - Acinetobacter
MRSA (if patient is MRSA positive or high prevalence)
Typical bacteria of CAP
Streptococcus pneumoniae, Haemophilus influenzae
Atypical bacteria of CAP
Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella
pneumophila
Rare pathogens of infections in immunocompromised patients – HIV, organ transplant, bone
marrow transplant, chemotherapy
Candida species, Aspergillus species (bone marrow), Pneumocystis jirovecii (HIV), Nocardia
species (found in soil), viruses
Lab test to send for pneumonia and bacteria
MCNS:
Microscopy, culture and sensitivity
Atypical: PCR
Beware of sputum Gram stain report – if there is high count of __________________, this indicates sample is poorly taken, result is unreliable
(respiratory tract infection)
- epithelial cells
Test done for Sputum,
Endotracheal aspirate (ETA)
BAL (bronchio-alveolar lavage)
(respiratory tract infections)
Gram stain: Beware of sputum Gram stain report – if there is
high count of epithelial cells, this indicates sample is
poorly taken, result is unreliable
Culture and sensitivity: For most bacteria
PCR: This is for detection of viruses because viral culture is not performed and ‘atypical bacteria’ in CAP
Test done for urine (respiratory infection)
Urine antigen test (point of care)
For Legionella pneumophila (difficult and takes time to grow)
For Strep pneumoniae (quick detection but beware of false positive result)
Test done for blood culture (respiratory infection)
Culture and sensitivity
If patient is febrile or septic
Organism responsible for cellulitis,
impetigo, folliculitis, furuncles,
carbuncles
Staph aureus
Beta-haemolytic Strep (esp Group A Strep)
Organism responsible for Erysipelas
Group A Strep is the main suspect
Organism responsible for Lymphangitis
Common and acute – Group A Strep, (Staph aureus)
Acute - Cat scratch (Pasteurella multocida)
Organism responsible for Intertrigo
Staph aureus, coliforms, Candida
Condition affected by Strep A
Cellulitis, impetigo, folliculitis, furuncles, carbuncles
Erysipelas
Lymphangitis
Organisms responsible for intertrigo
Staph aureus, coliforms, Candida
The organism responsible for Type 2
Necrotising facsciitis (NF)
Group A Strep
how to sample diabetic foot ulcer
Cleanse and debride the wound before obtaining specimens for culture
obtain a tissue specimen for culture by scraping with a sterile scalpel or dermal curette or biopsy from the base of a debrided ulcer
Aspirate any purulent secretions using a sterile container or appropriate transport media, for aerobic and anaerobic
For new onset infection (chronic wound/ diabetic foot ulcer) suspect..
suspect Staph aureus / streptococci
For chronic wounds (chronic wound/ diabetic foot ulcer) infection due to..
Infection due to Gram negative
organisms, or mixture of Gram positive and Gram negative
organisms
chronic wound/ diabetic foot ulcer use a ____________________to guide ____________________
deep tissue culture to guide antibiotic therapy
Organism responsible for septic arthritis (infection of a joint), osteomyelitis, discitis (infection of the spine)
Staph aureus
HIV transmission
Mainly blood-borne, unprotected intercourse are the main routes
Needlestick injury, vertical transmission i.e from mother to baby
Contact between damaged skin/mucosa with body secretions also poses a risk
Which immune cell is attacked by HIV
CD4 T cells
targets dendritic cells in mucosa
dendritic cells transport virus to CD4 T cells in lymph nodes
viraemia occurs -> high copies of HIV genomes in blood -> many patients become symptomatic at this point with fever, rash, sore throat and lymphadenopathy. This
period is self-limiting (days to weeks), and is known as “primary HIV infection” or “seroconversion syndrome”
Immune response is activated -> HIV antibodies develop and cytotoxic T cells proliferate -> controlling HIV infection and reducing the level of viraemia ->
achieving partial control of HIV
Progressive reduction in CD4 thereon, the speed of this reduction leading to AIDS varies from 1-2 years post infection to > 10 years post infection.
Clinical manifestation of HIV
Primary HIV infection / seroconversion syndrome
Years later (range from 1-2 to > 10 years later) ->
As CD4 count drops, patient presents with AIDS-defining infection(s), especially when
CD4 count drops < 200/μm3 ->
AIDS (Acquired immunodeficiency syndrome)
First line test of HIV
Antibody + p24 antigen combined screening test
eroconversion of antibody ranges from 7 days up to 90 days post infection, see “window” period below
“window” period : although patient is infected, antibodies cannot yet be detected in blood
p24 antigen or PCR test (to determine viraemia) can be useful during “window”
period
a positive test is confirmed by testing a second blood sample
HIV management
Lifelong HAART (highly active antiretroviral therapy)
Increase CD4 above 200 (HIV well-controlled)
Mode of transmission of salmonella species (S enteriditis- commonest)
Food
Mode of transmission of Salmonella typhi (‘typhoid fever’)
Salmonella paratyphi
Water-borne
Person to person (ingestion of food & water contaminated by faeces / urine of patients or carriers – hence we check for stool clearance)
Mode of transmission of Shigella species
Person to person
Mode of transmission of Campylobacter jejuni
Food (chicken!)
Mode of transmission of Vibrio species
Food (raw seafood / sushi)
Mode of transmission of Clostridium difficile
Antibiotic exposure - > person to person
Contaminated hospital environment
Salmonella species
(S enteriditis – commonest) usually ___________________.
Usually self-limiting
Salmonella typhi (‘typhoid fever’)
Salmonella paratyphi imported infection, not endemic in Sg, treated with _____________, patient at risk of
treated with antibiotics
Patient at risk of sepsis or seeding of infection if not treated
__________________ imported infection, not endemic in Sg
* Must be treated with antibiotics
* Patient at risk of sepsis or seeding of infection if not treated
Salmonella typhi (‘typhoid fever’)
Salmonella paratyphi
Shigella species comments
Usually self-limiting, maintain good hydration
Campylobacter jejuni comments
Usually self-limiting
Vibrio species comments
Usually self-limiting
Clostridium difficile comments
Needs treatment.
May lead to colitis/toxin megacolon/ DEATH!
Mode of transmission norovirus
Contaminated food (Shellfish) / water ->
human -> rapid human to human via faecal
oral or even formites
Mode of transmission rotavirus
Person to person
Mode of transmission adenovirus
Person to person
Norovirus
Well known cause of uncontrolled diarrhea in hospitals – leading to ward closure
Self-limiting
rotavirus
Most common cause of infant / paediatric diarrhea
Usually self-limiting
Adenovirus
2nd most common cause of infant /
paediatric diarrhea
Usually self-limiting
Stool for
Culture and sensitivity (gastrointestinal bacteria)
Salmonella species (including
typhi & parathyphi)
Shigella
Campylobacter
Vibrio (including cholera)
Stool for C diff toxin (gastrointestinal bacteria)
Clostridium difficile
Stool for EIA or PCR (gastrointestinal)
Rotavirus
Adenovirus
Norovirus
Sample to send for parasites
Entamoeba histolytica
Giardia lamblia
Cryptosporidium
Cyclospora
Microsporidia
Stool for ‘microscopy OCP’
Culture is not performed
OCP stands for Ova, Cysts & Parasites
Peritonitis
(peritoneum is sterile)
Usually due to perforation of intestines or gall bladder or other organs within abdomen :
- Appendicitis
- Colonic cancer
- Following bowel surgery
- C diff colitis & toxic megacolon
Corynebacterium diphtheriae
An acute bacterial infection involving tonsils, pharynx, larynx, as well as skin
Prevention of Corynebacterium diphtheriae
Vaccination – this is incorporated into the national vaccination programme in
developed countries
*Antibiotic prophylaxis of close contacts
For
1. perforation of intestines or gall
bladder or other organs within
abdomen
2. SBP
expect
- Coliforms
- Pseudomonas aeruginosa
- Anaerobes
- Enterococci
- Candida (a type of yeast)
For
1. perforation of intestines or gall
bladder or other organs within
abdomen
2. SBP
expect
- Coliforms
- Pseudomonas aeruginosa
- Anaerobes
- Enterococci
- Candida (a type of yeast)
AND
Members of skin flora (usually Coag
neg Staphylococcus)
Staph aureus
Other environmental bacteria
(because of the plastic tube!)
other intra abdominal infections expect
- Cholecytitis -> Cholangitis
- Diverticulitis
- Intra-abdominal abscess (usually post surgical)
- Liver abscess
- Pancreatic abscess
Coliforms
Anaerobes
Enterococci
Pseudomonas aeruginosa
Candida
Helicobacter pylori associated
peptic-ulcer disease
commonest pathogens of pharyngitis
Commonest pathogen – viruses eg. Rhinovirus (“common
cold”), EBV, CMV, Enterovirus, Adenovirus, Parainfluenza
Followed by Group A Streptococcus (aka Strep
pyogenes)
Notable pathogens causing pharyngitis Remarks
Viruses
Self- limiting
Notable pathogens causing pharyngitis Group A Streptococcus
Must treat with antibitoics to prevent complication (see
IMPORTANT below)
- Beware of tonsillar abscess – antibiotics and / or drainage
required
IMPORTANT :
* Look up complications following Group A Strep infection –
rheumatic fever /rheumatic heart disease, glomerulonephritis
OTITIS EXTERNA (OE)
infection in the external auditory canal – water trapped leading to infection
OTITIS MEDIA (OM)
obstruction of eustachian tube, typically
following viral infection
Bacteria responsible of otitis media
Streptococcus pneomuniae, Haemophilus influenzae, Staph aureus, Group A Strep
Common bacteria associated to sinusitis
Streptococcus pneumoniae
Haemophilus influenzae
Conjuctivitis
Common in children (nursery)
Can be highly contagious if bacterial
(hand touching eye -> touching another person)
Pathogens responsible for conjuctivits
Staph aureus
Strep pneumoniae
Haemophilus influenzae
Pseudomonas aeruginosa (contact lens)
N gonorrhea (serious, progress to keratitis)
Viruses : Adenovirus, Enterovirus, HSV etc.
Chlamydia trachomatis – STD in developed countries, transmitted by flies in poor countries!
Parasite : Microsporidia – from soil
encephalitis
infection / inflammation of cerebral cortex
Baterial meningitis causes
Normal population
* Neisseria meningitidis
* Streptococcus pneumoniae
* Haemophilus influenzae
- Group B Streptococcus (neonates)
- E coli (neonates)
- Listeria monocytogenes (neonates, pregnant women, immunocompromised)
BACTERIAL MENINGITIS – PREVENTION?
Vaccination against :
* Streptococcus pneumoniae
* Haemophilus influenzae
* Neiserria meningitidis
Household & close contacts -> chemoprophylaxis given if meningitis caused by :
* Haemophilus influenzae
* Neiserria meningitidis
IV antibiotic
VIRAL MENINGITIS management
supportive, self-limiting (compare with bacterial meningitis!)
detect viral encephalitis
Microbiology laboratory Diagnosis :
* CSF PCR
Chlamydia symptomatic or asymptomatic? (std)
asymptomatic
complications of genital chlamydia in male (std)
Urethritis
complications of Genital chlamydia in female (std)
Pelvic inflammatory disease-> infertility, tubo-ovarian abscess, ectopic pregnancy, chronic pelvic pain
complications of genital chlamydia in pregnant woman (std)
Risk of premature rupture of membranes, preterm delivery, low birth weight infants
complications of genital chlamydia in newborns (std)
C.Trachomatis acquired through an infected birth canal -> neonatal conjuctivits and pneumonia
Gonorrhaea,
symptomatic or asymptomatic?
early and symptomatic
Men: usually symptomatic
Women: Mostly asymptomatic
Persistent infection of HPV
persistent
infection with
high-risk* HPV
types
increases the
risk of cancer
e.g. cervical,
anal, oro-pharyngeal
Diagnosis of Syphilis:
Serology
Mycobacterrium tuberculosis transmission
Human-human transmission
Inhalation of droplet nuclei, aerosolised by coughing, sneezing, talking
MTB – who is at increased risk?
Intense exposure
*Immigrants from developing countries
*Malnutrition
*Alcoholics
*Homeless
*IV drug abusers
*Prison inmates
*Elderly people
*Very young
*HIV patients
*Immunocompromised
MTB: Sputum AFB smear positive
highly infectious
MTB: sputum AFB smear negative, culture positive
Less infectious
Testing for Latent TB Infection
Two accepted but imperfect tests:
TST (tuberculin skin test)
IGRA (Gamma Interferon Release Assay)
both tests depend on cell-mediated immunity (memory T-cell response), and neither test can accurately distinguish between LTBI and active TB disease
Active MTB – symptoms and signs
*Fever (due to Interleukin-1)
*Night sweats
*Weight loss (due to TNF)
*Chronic cough
Test for active TB:
Early morning sputum : at least 2 (normally 3 specimens)
*Nasogastric aspirate (in children who can’t expectorate sputa)
*Urine AFB culture (renal TB)
*CSF – AFB smear, culture, PCR
*Biopsy specimens: lymph nodes, bone, pleura
*Fluid: peritoneal fluid, pleural fluid, pericardial fluid
*Blood culture in miliary TB
Acid fast smear staining methods :
*Auramine phenol fluorescence technique (for screening)
*Ziehl-Neelsen (for confirmation)
Histology: presence of caseating granulomas and Acid Fast Bacilli
Active MTB- Culture
4-6 weeks
rapid test for presence of TB and drug resistance
PCR (information obtained on day 1)
Non-tuberculous Mycobacteria (NTM)
Most species (> 150 species) are worldwide and ubiquitous in the environment,
including household water, potting soil, vegetable matter, animals, and birds.
Cases in chronic (e.g., pulmonary) infections involve patients with underlying disease
such as bronchiectasis and cystic fibrosis.
Criteria of SIRS
Heart rate >90/min
Respiratory rate > 20/min
Pyrexia (> 38oC) or hypothermia (< 36oC)
Raised white cell count WBC > 12000 or leukopenia WBC < 4000
SIRS
(systemic inflammatory response syndrome)
ENDOCARDITIS- which micro sample to send?
3 sets of blood cultures (10ml each), BEFORE antibiotics are given
Why 3?
*To confirm the causative pathogen (ie. All blood cultures should grow the same
pathogen)
*Increase the chances of growing the pathogen
beforre antibitiotis
