bacterial infection (P - R) Flashcards
which bacteria causes pertussis?
bordetella pertussis - gram negative coccobacillus
who is at high risk of getting pertussis?
adolescents and adults who have not received a Tdap booster; infants, too young to be protected by a complete vaccination series
what are the symptoms of pertussis?
7-10 days after exposure; cough develops and becomes paroxysmal, often followed by vomitting.
fever is absent or minimal.
<2 months infant, case-fatality ~1%
how to diagnose Pertussis?
Culture and PCR
how to treat Pertussis?
macrolide AB (azithromycin, clarithromycin, or erythromycin) for age 1 months and old.
younger than 1 month old - azithromycin is preferred.
which vaccines are available for infants and children for pertussis?
5 doses of acellular pertussis vaccine (with diphtheria and tetanus- DTaP) at 2, 4, 6, 15-18 months, and at 4-6 years
children 7-10 years - single dose of tetanus toxoid, reduced diph toxoid, and acellular pertussis (Tdap)
what vaccines are available for adolescents and adults for pertussis?
11-18 yr: single dose of Tdap
>19 yr who have not previously received Tdap: single dose of Tdap
when should pregnant woman receive Pertussis?
at 27-36 weeks’ getation (earlier better)
who should get postexposure prophylaxis for pertussis?
all household contacts of cases and for people at high risk of developing severe disease
which bacterial agent causes Plague?
Yersinia pestis - gram negative coccobacillus
how dose plague transmitted?
- the bite of infected rodent fleas transmit Yersinia pestis
- handling infected animal tissues, inhaling infectious droplets from cats or dogs with plague; contact with a patient who has pneumonic plague (rare)
where is plague endemic in?
central and southern Africa (esp.. eastern Democratic Republic of the Congo, NW Uganda, Madagascar);
SW US, NE South America; central Asia, the Indian subcontinent)
what are the three possible clinical presentations of plague?
bubonic, pneumonic, septicemic
what is the clinical symptoms of bubonic plague?
rapid onset of fever and painful, swollen and tender lymph nodes (axillary, cervical, or inguinal)
what are symptoms of pharyngeal plague?
fever, sore throat, cervical lymphadenitis
what are the symptoms of pneumonic plague?
high fever, overwhelming pneumonia, cough, bloody sputum, and chills
what are the symptoms of septicemic plague?
fever, prostration, hemorrhagic or thrombotic phenomena, progressing to acral gangrene.
meningitis can also develop in up to 10% of patients with plague.
how to diagnose plague?
Yersinia pestis can be isolated from bubo aspirates, blood cultures, or sputum culture if pneumonic.
how to treat plague?
1st line: aminoglycosides and fluoroquinolones
bubonic or pharyngeal plague - can use doxycycline (not to be used for pneumonic or septicemic plague, or plague meningitis)
how to prevent plague?
What is postexposure prophylaxis?
reduce contact with fleas and potentially infected rodents and other wildlife.
oral AB including doxycycline, ciprofloxacin and levofloxacin can be Rxed for postexposure propylaxis.
what bacteria cause penumococcal disease?
Streptococcus pneumoniae - gram +, diplococcus
what is the major cause of bacterial meningitis and the most common bacterial cause of community-acquired pneumonia?
Streptococcus pneumoniae
Pneumococcal meningitis outbreak have occurred recently in countries in the meningitis belt of Africa. Infections from pneumococcus also have been reported in travelers attending mass gatherings (Hajj pilgrimage, Olympic Games) due to crowded conditions and limited space.
what is the major clinical syndromes of pneumococcal disease?
pneumonia, bacteremia, meningitis
what are the classical symptoms of pneumococcal pneumonia?
sudden onset of fever, malaise, pleuritic chest pain, cough with purulent or blood-tinged sputum, or dyspnea.
In older people, fever, shortness of breath, or altered mental status are possible initial symptoms.
what is the symptoms of pneumococcal meningitis?
headache, lethargy, vomiting, irritability, fever, neck stiffness, seizures
who is at increased risk of pneumococcal meningitis?
people with cochlear implants
how to diagnose pneumococcal infection ?
isolation of the organism from blood or other normally sterile body sites (pleural fluid, CSF)
tests also available to detect antigen in body fluids (e.g. urine)
how to treat community-acquired pneumonia empirically in outpatient settings?
children - amoxicillin
healthy adult - macrolides (azithromycin) or doxycycline
chronic or immunosuppressing condition - respiratory fluoroquinolone (moxifloxacin, levofloxacin) or a b-lactam plus a macrolide
how to treat community-acquired pneumonia empirically in inpatient settings?
initial tx - broad-spectrum cephalosporin plus a macrolide or a respiratory fluoroquinolone alone
for some pneumococcal infections, consider adding vancomycin until antimicrobial susceptibility results are available.
broad-spectrum cephalosporin + vanco –> pt with presumptive pneumococcal meningitis by CSF staining until susceptibility results are available.
who should get 13-valent pneumococcal conjugate vaccine (PCV 13) - 13 serotypes responsible for most severe illness?
infant immunization schedule
adult aged 65 and older
adult 19-64 with immunocompromising conditions
who should get 23-valent pneumococcal polysaccharide vaccine?
all adults aged 65 and over;
2-64 years with underlying medical conditions
who should get PCV 20?
all adults 65 and over and for adults 19-64 with underlying medical conditions - who have not previously received a pneumococcal conjugate vaccine or whose vaccination history is unknown.
which bacterial agent cause Q fever?
gram negative intracellular bacterium - Coxiella burnetii
how is Q fever transmitted?
inhalation of aerosols or dust contaminated with dried birth fluids or excreta from infected animals - cattle, goats, sheep –> very infectious and persists in the environment.
rarely - ingestion of contaminated unpasteurized dairy products and human-to-human transmission via sexual contact
which country do not have Coxiella burnetti?
New Zealand!
where is Coxiella burnetti most prevalent?
Africa and the Middle East
- higher in France and Australia than in US
- largest known Q fever outbreak ~4000 humans during 2007-2010 in the Netherlands
which occupation is at risk of Q fever?
butchers, farmers, meat packers, vet, seasonal or migrant farm workers
soldiers deployed to rural areas
travelers with livestock contact and consumption of unpasteurized milk
treatment/injection of fetal sheep cells
what are the acute symptoms of Q fever?
incubation 2-3 weeks - 50% mild or asymptomatic,
self-limiting febrile illness
hepatitis or pneumonia if more severe
what are the chronic symptoms of Q fever?
endocarditis
endovascular infections
who are at risk of getting chronic Q fever infections? (after months or years after the initial exposure)
patients with cardiac valvulopathies and vascular abnormalities or immunosuppression
which disease can cause risk for adverse pregnancy outcome?
Q fever (Coxiella burnetti)
how to diagnose actue Q fever?
serum samples collected 3-4 weeks apart - serologic antibody test (II IgG)
plus clinical evidence of infection
PCR testing of serum or whole blood is useful for confirmation of acute Q fever if samples are taken 14 or less days after symptom onset.
how to diagnose chronic Q fever?
requires a phase I Ig G titer >1:512 and clinical evidence of persistent infection (e.g. endocarditis, infected vascular aneurysm, osteomyelitis)
identifying C. burnetii in whole blood, serum, or tissue samples by PCR, immunohistochemical staining, or isolation can be used to confirm chronic disease.
how to treat acute Q fever?
doxycycline
pregnant, children <8 yrs with mild illness and pt allergic to doxycycline, trimethoprim-sulfamethoxazole is an alternative treatment option
no treatment if asymptomatic or symptoms have resolved
how to treat chronic Q fever?
long-term combo - doxycycline + hydroxychloroquine for 18 months or longer
alternative: trimethoprim-sulfamethoxazole and fluoroquinolones - less effective
might need surgery to remove infected tissue.
how to prevent Q fever?
vaccine only in Australia
no unpasteurized dairy products
what bacteria cause rickettsial infections?
Rickettsia, Orientia, Anaplasma, Ehrlichia, Neoehrlichia, Neorickettsia
how are Rickettsia spp. classically divided?
Spotted fever group (SFG) and typhus group
how are Rickettsia spp recently divided?
4 groups - 2 classical groups (spotted fever group and typhus group) and scrub typhus group and O. tsutsugamushi
which diseases are included in spotted fever group?
African tick-bite fever
Aneruptive fever
Astrakhan spotted fever
Cat flea rickettsiosis
Far Eastern spotted fever
Flinders Island spotted fever Thai tick typhus
Indian tick typhus
Israeli tick typhus
Japanese spotted fever
Lymphangitis-assoicated rickettsiosis
Maculatum infection
Mediterranean spotted fever (Boutonneuse fever)
Mediterranean spotted fever-like illness
North Asian tick typhus / Siberian tick typhus
Queensland tick typhus
Rickettsialpox
Rickettsiosis
Rocky Mountain spotted fever (also known as Brazilian spotted fever; febre maculosa; Sao Paulo exanthematic typhus; Minas Gerais exanthematic typhus)
Tickborne lymphadenopathy (TIBOLA) / Dermacentor-borne necrosis and lymphadenopathy (DEBONEL)
which diseases are included in Typhus Group?
Epidemic typhus / Sylvatic typhus
Murine typhus
which diseases are included in Scrub typhus group?
which rickettsial species cause scrub typhus?
what are the animal hosts and vectors?
scrub typhus
Orientia tsutsugamushi
O. chuto
O. chiloensis
host - rodents
vectors - trombiculid mites and chiggers
which diseases are included in Anaplasma group?
which rickettsial species cause this?
hosts and vectors?
human anaplasmosis
Anaplasma bovis
A. capra (goats, sheep)
A. ovis (sheep)
A. phagocytophilum (deer, small mammals, rodents)
A. platys (dogs)
vectors - ticks!
which diseases are included in Ehrlichia group?
human ehrlichiosis
what disease is included in Neorickettsia group? and which rickettsial species cause it?
Sennetsu fever
Neorickettsia sennetsu
animal hosts - fish
vectors - trematodes
what disease is included in Neoehrlichia group and which rickettsial species cause it?
Host and vectors?
Human neoehrlichiosis
Neoehrlicia mikurensis (animal host - rodents)
vectors - ticks
For ehrlichia group, which rickettsial species (6) cause human ehrlichiiosis?
What is the vector?
Ehrlichia chaffeensis (deer, domestic and wild dogs, domestic ruminants, rodents)
E. ewingii
E. muris eauclairensis
E. muris muris
E. canis (dogs)
E. ruminantium (domestic and wild ruminants)
vector - ticks
how are rickettsial pathogens transmitted?
- directly by infected arthropod vectors (fleas, lice, mites, or ticks) during feeding
- scratching skin contaminated with an arthropod’s infectious fluids or feces, or by crushing the arthropod vector at the bite site
- inhaling bacteria or inoculating conjunctiva with infectious materials
- Anaplasma and Ehrlichia spp through trasnfusion of infected blood products or by organ transplantation
what is the most diagnosed rickettsial diseases in travlers?
tickbrne spotted fever (African Tick-bite fever caused by R. africae)
which travelers would be at risk for African tick-bite fever (caused by R. africae)?
Travelers who go on safari—especially those traveling to national parks, game hunters, and ecotourists to sub-Saharan Africa
which bacteria cause Cat Flea Rickettsiosis?
R. felis
which agent causes Mediterranean spotted fever (also known as Boutonneuse fever)?
R. conorii
which spotted fever occur over a larger geographic area? (including but not limited to Africa, much of Europe, India, the Middle East)
Mediterranean spotted fever (Boutonneuse fever) caused by R. conorii
what is the causative agent of rickettsialpox?
R. akari
rickettsialpox is transmitted by which vector?
house mouse mites
R. akari circulates mainly in … ?
urban centers in the Balkan states, Korea, South Africa, Ukraine, and the US
what is the other name for Rocky Mountain Spotted Fever? and what is the causing agent?
Brazilian spotted fever
R. rickettsii
where does the Rocky mountain spotted fever occur?
Western Hemisphere - Canada, Mexico, US, Central & South America including Argentina, Brazil, colombia, Costa Rica, Panama
what is the host of Rocky Mountain spotted fever ticks?
rodents
which is the causing agent for Louseborne or epidemic typhus?
R. prowazekii
who is at risk of Louseborne or epidemic typhus?
people living in crowded conditiosn where body lice are prevalent (refugees housed in camps, incarcerated populations)
travelers who provide medical or humanitarian aid to people living in refugee camps and those who visit impoverished areas affected by war, famine, or natural disasters
which area is the active foci of epidemic typhus?
Andes regions of South America, some parts of Africa, including but not limited to Burundi, Ethiopia, and Rwanda
what causes Murine Typhus? and what is the host? and vector?
R. typhi
rodents, cats, dogs, peridomestic animals
flea
how are scrub typhus transmitted?
through species of trombiculid mites that live in high grass and brush
where is scrub typhus endemic to?
east asia (china, norther japan), SE Asia (India, Indonesia, Sri Lanka), the Pacific (eastern Australia), and several parts of south-central Russia.
Cases of disease also have been described from several unexpected regions, including the United Arab Emirates and southern Chile, and appear to be caused by newly recognized species of Orientia.
which tickborne infections are commonly reported in the US?
anaplasmosis and ehrlichiosis
Sennetsu fever, caused by N. sennetsu, occurs in Japan, Malaysia, and parts of SE Asia - this disease can be contracted from eating.. what?
raw fish infested with neorickettsiae-infected flukes
what is the incubation period of most rickettsial diseases?
5-10 days
which rickettsial diseases can be life-threatening when treatment is delayed?
Rocky mountain spotted fever, epidemic typhus, scrub typhus, and Mediterranean spotted fever
what are the common symptoms that typically develop within 1 week of rickettsial infection?
- fever, headache, malaise, nausea, vomiting
- many rickettsioses aso are accompanied by a maculopapular, petechial, or vesicular rash, or sometimes an eschar (a dark necrotic scab) at the site of the tick or mite bite
person presenting with fever, headache, myalgia, and one or more eschars after recent travel to sub-Saharan Afrian or the Caribbean - which infection is likely?
African Tick-bite fever
patient with fever, rash, an eschar after recent travel to northern Africa or the Mediterranean Basin - what is likely?
Mediterranean spotted fever
patient with fever, headache, abdominal pain, nausea, progress rapidly into a serious systemic disease.
a maculopapular or petechial rash, but no eschars -
what rickettsial disease is likely?
rocky mountain spotted fever
patient with fever, leukopenia -
which rickettsial diseases can you suspect?
anaplasmosis & ehrlichiosis
why is rickettsial diseases hard to diagnose?
results are highly dependent on the type and timing
what is the empiric treatment for rickettsioses?
-tetracycline (doxycycline) for all ages
-if A. phagocytophilum or R. africae infection - rifampin can be an alternative (if pregnant or doxycycline-intolerant patient)
-chloramphenicol can be an alternative for Orientia and Rickettsia species, but use is associated with more deaths, particularly with R. rickettsii infection.
