Microbiology - systems Flashcards
normal flora dominant - skin / nose / oropharynx / dental plaque, colon, vagina
skin –> S. epidermidis
nose –> S. epidermidis, colonized by S. aureus
oropharynx: viridans
dental plaque: S. mutans
colon: Bacteroid fragilis > E. coli
vagina: lactobacillus, colonized by E. coli and group B strep
Foods poisoning - bugs (and source)
- B. cereus (reheated rice)
- C. botulinum (inproperly canned foods, raw honey)
- C. perfingerns (reheated meat)
- E. coli O157:H7 (undercooked meat)
- Salmonealla (poultry, meat eggs)
- S aureus (meats, mayonnaise, custard) –> preformed toxin
- V. parahaemolyticus and V. vulnificus (contaminated food)
Beside food poisoning, V. vulnificus can cause
wound infection from contact with contaminated water or shellfish
Bags that cause bloody diarrhea
- campylobacter jejuni
- E. histolytica
- EHEC
- EIEC
- Salmonella
- Shigella
- Y. enterocolitica
- C difficile
salmonella source
eggs, pets, turtles,
Y. enterocolitica - situations
day care oubreaks
Y. enterocolitica causes
- bloody diarrhea
2. pseudoappendicitis
bacillary dysentery is caused by
shigella
Watery diarrhea - bacs
- C difficile
- C. pefringens
- ETEC
- Protoza (giardia, Cryptosporidium)
- V cholerae
- Viruses (Rotavirus, norovirus, adenovirus)
Viruses that causes watery diarrhea
Rotavirus, norovirus, adenovirus
common cuase of pneumonia in neonates (less than 4 weeks)
- S. agalactiae
2. E. coli
common cuase of pneumonia in children (4wks - 18yr) (in order)
- viruses (RSV)
- mycoplasma
- C. trachomatis (infants - 3 years)
- C. pneumoniae (school-aged children)
S. pneumoniae
common cuase of pneumonia in adults (18-40yr) (in order)
- mycoplasma
- C. pneumoniae
- S. pneumoniae
- viruses (eg. influenza)
common cuase of pneumonia in adults (40-65yr) (in order)
- S. pneumoniae
- H. infuenzae
- Anaerobes
- viruses
5, Mycoplasma
common cuase of pneumonia in elderly (in order)
- S. pneumoniae
- Influenza virus
- Anaerobes
- H Influenzae
- Gram (-) robs
pneumonia in alcoholics/iv drug users - bugs
S. pneumoniae, klebsiella, S. aureus, anaerobes
pneumonia with aspiration - bugs
anaerobes
atypical pneumonia - bugs
mycoplasma, legionella, chlamydia
pneumonia with cystic fibrosis
pseudomonas (adolscent), s. aureus (infants),
s. pneumoniae
+ Burkholderia cepacia
postviral pneumonia - bugs
s. aureus, H. infuenzae, S pneumoniae
Nosocomial (hostpital acquired) pneumonia - bugs
s. aureus, Pseudomonas, other enteric gram (-) negative robs
pneumonia in immunocompromised
s. aureus, enteric gram-negative robs, fungi, viruses, P. jirovecii (with HIV)
common cause of meningitis in newborn (0-6months) (in order)
- Group B streptococci
- E. coli
- Listeria
common cause of meningitis in children (6months-6yr) (in order)
- S. pneumoniae
- N. meningitis
- H. influenzae type B
- Enteroviruses
common cause of meningitis in 6-60 years (in order)
- S. pneumoniae
- N. meningitis (1st in teens)
- Enteroviruses
- HSV
common cause of meningitis in 60+ (in order)
- S. pneumoniae
- Gram - robs
- Listeria
meningitis - how to treat
give ceftriaxone + vancomycin (empirically)
add ampicillin if Listeria is suspected
viral causes of meningitis
- enteroviruses (esp coxsackievirus)
- HSV-2
- HIV
- West Nile virus (also causes encephalitis)
- VZV
West Nile virus causes
encephalitis and meningitis
HSV causes (on CNS)
HSV-1 –> encephalitis
HSV-2 –> meningitis
H. influenzae - meningitis?
incidence has decreased greatly with indroduction of the conjugate. H. influenzae vaccine in last 10-15 yrs. Today, cases are usually seen in unimmunized children
CSF findings in bacterial meningitis
- Increased opening pressure
- increased PMNs
- increased protein
- decreased sugar
CSF findings in fungal meningitis
- Increased opening pressure
- increased lymphocytes
- increased protein
- decreased sugar
CSF findings in viral meningitis
- normal/Increased opening pressure
- increased lymphocytes
- normal/increased protein
- normal sugar
CSF findings in TB meningitis
- Increased opening pressure
- increased lymphocytes
- increased protein
- decreased sugar
infections causing brain abscess - most commonly by
Viridans streptococci and S. aureus
infections causing brain abscess - if dental infection - bugs?
oral anaerobes
infections causing brain abscess - if extraction precedes abscess
oral anaerobes
infections causing brain abscess - Multiple abscess are usually from
bacteremia
infections causing brain abscess - single lesion from contiguous sites - sites (and area of the brail lesion)
- otitis media –> temporal lobe and cerebellum
- mastoiditis –> temporal lobe and cerebellum
- sinusitis –> frontal lobe
- dental infection –> frontal lobe
MCC of osteomyelitis
S. aureus
osteomyelitis associated with IV drug use - bugs
- pseudomonas
- Candida
- S. aureus
osteomyelitis associated with sickle cell anemia - bugs
osteomyelitis associated with cat and dog bites - bugs
SC anemia: salmonella and S. aureus
dog: pasteruella multocida
osteomyelitis associated with sexually active - bugs
Neisseria gonorrhoeae (RARE) septic arthritis more common
osteomyelitis associated with prosthetic joint replacement - bugs
S. aureus and S. epidermidis
osteomyelitis with vertebral involvement - bugs
S. aureus
M. tuberculosis (Pott disease)
osteomyelitis - test for diagnosis (and characteristics)
- elevated CRP (nonspecific)
- elevated sedimentation rate (nonspecific)
- MRI –> best for detecting acute infection and detailing anatomic involvement
- Radiographs –> insensitive early but can be useful in chronic osteomyelitis