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
