Gram - Infections Flashcards
E coli gastroenteritis
Where do you get infection from?
originates from fecal matter, but then gets contaminated into meat at processing plants.
raw flour unpasteurized products, contaminated leafy greens.
E coli gastroenteritis
Enterotoxigenic E Coli (ETEC)
Heat stable or heat labile toxin
Important source of traveler’s diarrhea
E coli gastroenteritis
Enteroinvasive E. Coli (EIEC)
Invade cells leading to bloody diarrhea and dysentery
Uncommon in US
E coli gastroenteritis
Shiga toxin-producing E. Coli (STEC)
E. Coli O157:H7 most common in US.
E coli gastroenteritis
What are symptoms of STEC- (5)?
Who is most likely to have complications?
Asymptomatic carrier stage
Nonbloody diarrhea
Hemorrhagic colitis
Hemolytic-uremic syndrome (HUS)- rare
Thrombotic thrombocytopenic purpura (TTP)
small vessel clots that cause organ problems
worst cases in geriatric and pedicatric pts.
E coli gastroenteritis
what is Hemolytic-uremic syndrome (HUS)
RBCs are lysed and damage kidneys upon filtration of blood.
HUS can be caused by any hemolytic anemia.
E coli gastroenteritis
What is Thrombotic thrombocytopenic purpura (TTP)?
small vessel clots that cause organ problems
STEC
how do we Dx?
get stool culture and check for specific shiga toxin.
STEC
how do we Tx?
supportive care
antibiotics shorten clinical course, Ciprofloxacin 500mg 2x daily
REQUIRES REPORTING TO HEALTH DEPARTMENT
Salmonellosis
how is it contracted?
ingestion via food or drink
Salmonellosis
what spp is most common in causing salmonella in humans?
Salmonella enterica
Salmonella
Enteric fever
Typhoid fever
salmonella
what spp causes enterocolitis?
S. typhimurium subspecies
salmonella
what spp causes sepsis?
S choleraesius subspecies
Salmonella
Enteric (typhoid) Fever patho & incubation
6-30day incubation
ingested then infects small intestine wall, then* can* enter lymphatic system which can lead to sepsis.
Some people are carriers (in lymph without symptoms)
Salmonella
Symptoms
wax and waning symptoms- may release up tp 2 weeks after fever resolves in 15% of cases.
Prodromal stage (7-10 days) - malaise, headache, cough, sore throat, abd pain, constipation or pea soup poop, fever that increases over time
Salmonella
Later Sx with typhoid
Splenomegaly (lymph infection)
Abdominal distention/tenderness.
Relative bradycardia.
Meningismus.
Rash “rose spots” 2nd week
Typically on trunk
Pink papule 2-3mm that fades with pressure
Resolves in 3-4 days
Salmonella
how do we Dx typhoid fever?
leukopenia, blood cultures(+ result in 80% in 1st week of illness, 25% by 3rd week.
stool cultures are unreliable, may be + w/o typhoid fever
salmonella
Complications of typhoid
2% mortality rate in treated patients
Occurs in 30% of untreated cases
Intestinal hemorrhage
Intestinal perforation
salmonella
less common complications of typhoid
Pneumonia, thrombophlebitis, myocarditis, psychosis, cholecystitis, nephritis, osteomyelitis, meningitis
Salmonella
how do we Tx symptomatic typhoid?
Levofloxacin (Levaquin) 750mg PO twice daily or once daily
5-7 days for uncomplicated
10-14 days for severe infections
Salmonella
How do we Tx typhoid carriers?
Ciprofloxacin (Cipro) 750mg PO twice daily for 4 weeks
Salmonella
how do we prevent Typhoid fever?
consider immunization, multi-dose oral vaccine or single dose parenteral vaccine
adequate waste disposal
protect food and water supplies
carriers CANNOT work as food handlers.
Salmonella
Acute enterocolitis Sx
Fever +/- chills
Nausea/vomiting
Cramping abdominal pain
Diarrhea, may be bloody (3-5 days)
Salmonella
how long is the incubation for salmonella gastroenteritis?
8-48 hours
salmonella
How do we treat critically ill salmonella gastroeneteritis? Dx?
Diagnosis by stool culture
Typically, self limited
Rarely may cause bacteremia with localization to joints
Critically ill patients
Ciprofloxacin (Cipro) 500mg PO twice daily for 7-14 days
Yersinia
What disease is caused by Yersinia?
Bubonic Plague (80-95% of cases)
Yersinia
how is it spread? Incubation?
wild rodents and ticks
organism spreads through lymphatics
7-10 day incubation.
spreads between humans via droplets (pneumonic plague)
yersinia
what are complications of infection?
spread from lymph to lungs or meninges
Yersinia
Signs of bubonic plague
- Tachypnea
Productive cough
Blood-tinged sputum
Cyanosis
Meningeal signs
Lymphadenopathy (LAD)
Purpuric spots
Due to disseminated intravascular coagulation(DIC)- purple spots
yersinia
symptoms of bubonic plague
Sudden onset
High fever
Malaise
Tachycardia
Intense headache
Delirium-pneumonic plague
Severe myalgias
Yersinia
how do we Dx?
aspirate buboes(lymph node) or antibody titer
yersinia
how do we Tx bubonic plague? Prophylaxis?
Immediate with any suspicion
Streptomycin 1gm IV every 12 hours x 10 days
Respiratory isolation if pneumonia
Antibiotic prophylaxis for any exposure
Doxycycline (Vibramycin) 100mg PO twice daily x 7 days
Haemophilus
are likely to colonize …?
upper respiratory tract in patients with COPD (and w/o)
Haemophilus
what can haemophilus cause?
upper resp infect.
sinusitis, otitis, bronchitis, epiglottitis, pneumonia, cellulitis, arthritis, meningitis, and endocarditis
Haemophilus
how do we Tx Haemophilus?
Non beta-lactamase producing strains
Amoxicillin
Beta-lactamase producing strains (more common in children)
Amoxicillin-Clavulonate (Augmentin)
PCN allergic: Cefuroxime
Moraxella catarrhalis
where does it colonize? and what does it cause?
respiratory tract
causing Sinusitis, bronchitis, and pneumonia
sometimes bacteremia and meningitis in immunocompromised patients
moraxella catarrhallis
how do you treat?
because it produces beta-lactamase you use Amoxicillin-Clavulanate
bordetella pertussis
what disease does it cause?
whooping cough (can lead to failure to thrive in infants)
bordetella pertussis
how is it transmitted?
by respiratory droplets
Sticks to cilia and respiratory epithelia
bordetella pertussis
how long is incubation?
7-17 days
bordetella pertussis
who is mostly affected?
infants <2yo
Pertussis in 3rd trimester or 1st year after delivery poses huge risk to infant. Can be fatal.
bordetella pertussis
what are the 3 stages?
and how long does infection typically last?
Catarrhal stage (1-2 weeks)
Paroxysmal stage (acute, rapid)
convalescent stage (4 weeks after onset/ recovering)
total of 6 weeks, can have lasting damage
bordetella pertussis
Catarrhal stage
Most infectious
Lacrimation
Sneezing
Coryza
Hacking cough at night that becomes diurnal
Malaise
Anorexia
bordetella pertussis
Paroxysmal stage
(acute, rapid)
Rapid consecutive coughs followed by deep high-pitched inspiration
bordetella pertussis
Convalescent stage
Decrease in frequency and severity of cough
Bordetella pertussis
how do we Dx whooping cough?
nasopharyngeal culture using Bordet-Gengou agar
some may have PCR assay
bordetella pertussis
how do we Tx exposure?
Erythromycin 500mg PO QID x 7 days
If macrolide allergy, use TMP-SMX
bordetella pertussis
how do we treat sympomatic pts?
Supportive Care- Maintain hydration and nutrition, maintain airway, control secretions
Admit- Consider referral to infectious disease
Droplet precautions/standard precautions
bordetella pertussis
when do we admit pts? ICU?
Admit if sustained hypoxia, failure to thrive, encephalopathy, or seizures.
Consider ICU for: infants < 3 months, infants 3 - 6 mo with severe paroxysms, premature infants, infants with underlying cardiac, pulmonary, neuromuscular disease
Bartonella
what diseases can it cause?
Cat scratch disease
bartonella
what is cat scratch disease?
Acute infection of children and young adults by Bartonella henselae
Transmitted by cat scratch or bite
Within several days, a papule or ulcer forms at injury site
1-3 weeks later, develops fever/HA/malaise. Regional LAD occurs.
bartonella
how do we Dx and Tx?
Typically, a clinical diagnosis
Bartonella cultures available
Self limited disease but can treat with ABX (azithromycin)
Legionella
what diseases does it cause?
1.Legionnaires disease
2.amoung top 4 causes of community acquired pneumonia
3.atypical pneumonia
legionella
where do you get it?
who is at risk?
contaminated water
underlying chronic lung disease, tobacco use, immunocompromised
Legionella
what is unique about gram staining this organism?
Gram stain of sputum does not show organism
legionella
what are the symptoms of legionnaires disease?
High fever
Pleurisy
Purulent sputum
Toxic appearance
Nausea/vomiting/diarrhea
SOB
muscle fatigue
Legionella
what are signs of infection?
Elevated liver enzymes
Elevated creatine kinase
Culture of Legionella 80-90% sensitivity
Urine antigen an option but less sensitive
More recently, sputum by PCR
legionella
How do we Tx?
Azithromycin 500mg once daily x 10-14 days
21 days for immunocompromised patients
Neisseria Meningitidis
which group is most common for epidemic in US?
Group C
Neisseria Meningitidis
what are symptoms?
High fever/chills
Nausea/vomiting
Extremity pain
Rapidly developing confusion, delirium, seizures, and coma
Petechial rash lower extremities
Extremity pain
Neisseria Meningitidis
what are the signs of infection?
Nuchal and back rigidity
+ Kernig sign
Pain in hamstrings upon extension of knee with hip at 90-degree flexion
+ Brudzinski sign
Flexion of knee in response to flexion of the neck
Neisseria Meningitidis
what is Kernig’s sign?
Neisseria Meningitidis
what is Brudzinski’s sign?
Neisseria Meningitidis
How do we Dx?
Lumbar puncture will be cloudy or purulent CSF, increased pressure, increased protein, decreased glucose
Culture and smear
CSF
Oropharynx
Blood
Aspirated petechiae
Neisseria Meningitidis
how do you Tx
Hospitalization
Must obtain blood cultures before antibiotic administration is begun
Ok to start prior to LP
Aqueous Penicillin G 4 million units IV every 4 hours
Increasing resistance
PCN allergic: Ceftriaxone (Rocephin) 2gm IV every 12 hours
Continue treatment until afebrile >5 days
Neisseria Meningitidis
how do we prevent infection?
4 types of infection depending on age.
Shigella
what disease does it cause?
dysentery (shigellosis) is most common
Shigella
what is the most common spp in the US? and which is the close second?
S. sonnei is the leading cause (followed by S. flexneri) in the US
Shigella
what spp is likely to cause serious and potentially fatal dysentery?
S. dysenteriae
Shigella
what is mode of transmission?
Fecal oral route
contaminated food/water
Shigella
what are the symptoms of infection?
Abrupt onset
Diarrhea, often with blood & mucus
Crampy lower abdominal pain
Tenesmus(urge to poop without anything coming out)
Fever/chills
Anorexia
Malaise
Headache
HUS - hemolytic uremic syndrome
Shigella
what are the signs of infection?
Abdomen is tender
Sigmoidoscopic exam reveals:
Inflamed, engorged mucosa with punctate
Sometimes large ulcerations in large intestine.
Shigella
how do we Dx?
Stool has many leukocytes and RBCs
Usually stool culture + for Shigellae
<5% + blood cultures
Shigella
What are some complications of infection?
Temporary lactose intolerance
Reactive arthritis
Hemolytic-uremic syndrome
Shigella
How do we Tx infection?
usually supportive care
consider antibiotics in severe cases, geriatrics, malnourished.
Ciprofloxacin (Cipro) 750mg orally twice daily for 7-10 days
Levofloxacin (Levaquin) 500mg PO once daily for 3 days
High amoxicillin resistance rates
Vibrio cholerae
what illness is produced and what are risks?
acute diarrhea, cholera, toxin mediated, death due to hypovolemia
Vibrio cholerae
what is the pathophysiology?
Attaches to small intestine epithelial cells
Triggers secretion of chloride and inhibition of sodium chloride absorption **
Massive fluid secretion into small intestine (‘water follows salt’)
Up to 15L/day
Vibrio cholerae
where do epidemics occur?
Epidemics occur with crowding, war, famine, or with inadequate sanitation
Vibrio cholerae
what are signs and symptoms?
Sudden onset severe frequent watery diarrhea
Up to 1L/hr
Diarrhea is gray and turbid “rice water stool”
No fecal odor, blood, or pus
Typically, afebrile
Rapid development of dehydration and hypovolemia
Vibrio cholerae
How do we Tx cholera?
Replace fluid and solute losses
Tx with antibiotics shortens course of illness
Doxycycline (Vibramycin) orally or IV (route dependent on sx) or azithromycin orally single dose
Vibrio cholerae
how do we Dx?
Stool culture should be +
Rapid antigen tests of stool
