Medically Important Bacteria

normal bacterial flora are referred to as _

commensals

benefits of normal flora (4)

minimizes survival of invaders

secretes antimicrobial susbtances

stimulates immune development

source of nutrients for the gut

when do friendly bacteria become foes

when the microbe is displaced and enters a sterile site

loss of balance

impaired host immunity

characteristics of medically important bacteria

-grows somewhere it shouldn't

-causes disease

methods to classify bacteria based on phenotype (4)

gram stain/morphology

growth requirements

biochemical reactions

serological methods

genotypic methods of classifying bacteria (3)

phylogenetic tree

rRNA sequencing

molecular subtyping

KOH test identifies _

fungal microbes

acid-fast staining is used to identify

Mycobacterium species

india ink stain is used to identify _

cryptococcus

main difference between gram negative vs gram positive bacteria

peptidoglycan + outer membrane presence

anaerobic bacteria produce energy via _

fermentative pathways

organisms that preferentially use oxygen for metabolism, but may rely on anaerobic respiration

facultative anaerobes

aerotolerant anaerobes relationship to oxygen

unaffected by presence of oxygen

blood agar tests for organism's ability _

to hemolyze RBCs in the media

alpha hemolysis

partial hemolysis

beta hemolysis

complete hemolysis

gamma hemolysis

no hemolysis

all _ species are catalase positive

staphylococcal species

blood agar is used to study which bacteria?

streptococci

catalase positive bacteria produces _ when placed in _

water and O2 ; hydrogen peroxide

if catalase is negative, consider _ bacteria

streptococcus

chocolate agar contains _

hemin (X factor)

NAD

types of bacteria to consider with chocolate agar

respiratory

urogenital

coagulase is for identifying _

Staph auereus

what does coagulase do in slide test

converts fibrinogen in plasma -> fibrin

free coagulase produces _

clot

macconkey agar is _ medium

selective and differential

bile salts of macconkey agar has what function

selectively inhibits gram positive bacteria

macconkey test differentiates _

gram-negative bacilli on their ability to ferment lactose

oxidase test detects _

cytochrome c oxidase

cytochrome c oxidase function

catalyzes transport of electrons from NADH to electron acceptors

urease function

hydrolyzes urea

how does urease test work

relies on production of ammonia (basic pH)

The cumulative results of hospital performed bacterial susceptibility testing organized into a summary table

antibiogram

antibiogram serves as a reference guide to _

resistance patterns for an entire hospital setting

what is sent when a culture and sensitivity test is ordered?

a biological sample collected from the suspected site of infection

choose an antibiotic that > _ % of the bacteria is susceptible

85%

therapy in which antibiotics are used to reduce anticipated risk

prophylactic

empiric therapy

antibiotics are used to target a certain suspected infection while workup is in progress

almost all early antibiotic treatment is _ therapy

empiric

what info do we get back on a bacterial culture and sensitivity

identification of bacteria

susceptibility to bacteria

therapy where the diagnosis is known and a certain pathogen is targeted

definitive therapy

symptoms of staph A infections

pneumonia

infective endocarditis

sepsis

osteomyeletits

menstural toxic shock syndromes

soft tissue infections

staphylococcus aureus causes which infections

abscesses

skin + soft tissue

endocarditis

osteomyelitis

septic arthritis

impetigo

which bacteria is associated with infection from implanted devices

Staphylococcus epidermidis

bacteria associated with dental caries

strep viridans

bacteria associated with exotoxin-mediated diseases

staphylococcus aureus

diseases associated with strep pneumo

pneumoniae, meningitis, otitis, sinusitis

strep pyogenes is associated with what diseases

GAS

pharyngitis

cellulitis

impetigo

TSS

staph A vs staph epidermidis differentiating factor

staph A is coagulase positive

neonatal meningitis is caused by _

strep agalactiae

group B strep

strep agalactiae

who is susceptible to streptococcus pneumoniae

young children

elderly

those with chronic diseases

chronic diseases that make individuals vulnerable to pneumonia

DM

COPD

HIV

splenectomy

malnourished

alcoholism

community acquired pneumonia

pneumonia in a previously healthy person who acquired the infection OUTSIDE of the hospital

causes of acute bacterial meningitis

strep pneumoniae

N. meningitidis

bacterial from dental procedures can cause _

endocarditis

brain abscess

main habitat of strep agalactiae

vagina

E. faecalis hemolysis group

gamma

E. faecalis associated diseases

UTI

biliary tract infection

E faecalis habitat

human colon

spore forming gram positive bacilli

Clostridia

NON-spore forming gram + bacteria

listeria monocytogenes

where is clostridium perfringens found

soil and human colon

cause of gas gangrene

Clostridium perfringens

Clostridium perfringens causes _

gas gangrene

food posioning

C. diff toxin A

inflammatory colitis

C. diff toxin B

cytotoxin

frequent antibiotics associated with C. diff

ampicillin

augmentin

cephalosporins

clindamycin

occasional C. diff antibiotics

penicillins

quinolones

rare/never C. diff antibiotics

tetracyclines

metronidazole

listeria monocytogenes is mostly _ borne

food

how does listeria monocytogenes cause infection

enters cells via phagocytosis

releases listeriolysin toxin

listeria toxin

liesteriolysin

food associated with meningitis in pregnancy

soft cheeses

transplacental meninigitis cause

listeria monocytogenes

foods associated with listeria monocytogenes

dairy

poultry

ground meat

aerobic gram negative bacilli

H. influenzae

Legionella pneumophilia

pseudomonas aeruginosa

pasteurella multocida

virulence factor of H. influenzae

capsule

H. influenzae type B causes what diseases

meningitis

epiglottitis

septic arthritis

how does unencapsulated H. infleunza spread

contiguous spread along tissue planes

unencapsulated H. influenzae causes

otitis media

sinusitis

bronchitis

pneumonia

most common H. influenza strain

type B (encapsulated)

cause of atypical lobar pneumonia

legionella pneumophila

legionella pneumophila causes what diseases

legionnaire's

pontiac fever

pontiac fever

mild flu-like URTI

main successful opportunistic pathogen

pseudomonas aeruginosa

where can pseduomonas aeruginosa infections occur

skin

hospitals

UTI

respiratory tract

bacteria associated with cat bites

pasteurella multocida

_ develops after a cat bite

painful cellulitis

PMN cells are also known as

granulocytes

moraxella catarrhalis associated with which diseases

bronchitis

sinusitis

otitis media

N. gonorrhoeae can cause _

pharyngitis

cervicitis

gonorrhea

important sign of sepsis that accompanies meningitis

meningoccocal rash

intra and extra intestinal disease bacteria

E. coli

salmonella

proteus species

intra-intestinal bacteria

shigella

camplyobacter jejuni

H pylori

bacteriodes fragilis

extra-intestinal disease bacteria

Klebsiella pneumonia

E coli transmission

contaminated water/food

E. coli associated diseases

neonatal sepsis, meningitis

UTIs

diarrheal diseaes

neonatal sepsis causative bacteria (3)

S. agalactiae

E. coli

L. monocytogenes