Microbiology Flashcards
Neisseria gonorrhoeae has the ability to avoid host defenses because of:
Antigenic variation
*Neisseria are gram negative diplococci, in pairs, coffee bean shaped or kidney shaped
Nisseria gonorrhoeae: Only oxidize glucose
Nisseria meningitidis: oxidize glucose & maltose
Nisseria lactamica: glucose, maltose, & lactose
Nisseria gonorrhoeae
- usually produce small colonies
- cultures from symptomatic urethritis are opaque colonies
- ophthalmia neonatorum is acquired during passing through birth canal
treatment of ophthalmia neonatorum
Antibiotic eye ointment:
Erythromycin or tetracycline
Crede’s prophylaxis - classical/ silver nitrate
Resistance of nafcillin by Staphylococci is mainly due to:
Staphylococcal cassette chromosome mec
spec. mecA gene —> MRSA
DOC for CA-MRSA: Clindamycin
HA-MRSA: Vancomycin
In CA-MRSA infections, the important virulence factor that can kill WBC is:
Panton-Valentine Leukocidin
(Targets PMN)
*Catalase- breakdown Hydrogen peroxide
(+)- bubbling or efervesence
*Hemolysins- lysis of RBC
S. pneumonia
> Gram positive diplococci, lancet shaped or arranged in chains
Possess a capsule of polysaccharide that permits typing with antisera
Growth is enhanced by 5-10% CO2- loves CO2 called Capnophilic
Not true: not readily lysed by surface-active agents
Enterococci
> group D cell wall-specific antigen is a teichoic acid and is not an antigenically good marker
nonhemolytic but are occasionally alpha-hemolytic
PYR positive
grows in the presence of bile and hydrolyze esculin
False: intrinsically susceptible to Monobactams- target cell wall
Only monobactam available— Aztreonam
Salmonella that usually manifests with early invasion of the bloodstream w/ possible focal lesions in the meninges but intestinal manifestations are often ABSENT
S. choleraesuis - more on septic presentations but no intestinal manifestations
*S. Typhi - enteric fever; septic px
Antigenic structure that is located on the most external part of the cell wall lipopolysaacchride and consists of repeating of polysaccharide
O antigen
-E. Coli most notorious to cause Hemolytic Uremic Syndrome (HUS)/ Hemorrhagic colitis= O157;H7
*Remember:
H antigen is located in the FlHHHagela
O antigen is located in the cell wOll/wall
K antigen is located in the Kapsule/capsule
Pseudomonas
- causative agent of Hot tub folliculitis, Jacuzzi syndrome
> grows well at 37-42 degrees celsius
oxidase positive
TAKE NOTE: gram negative enteric organisms (E. Coli, Klebsiella, Enterobacter) are oxidase NEGATIVE
> gram negative, motile, rod-shaped bacteria
NOT TRUE: pathogenic when present regardless of location in the body
> greenish discoloration because of Pyoverdin pigment (others Pyocyanin)
“Blue Pus”
Ecthyma gangrenosum - skin lesions
malignant otitis externa
Yersinia pestis - caused plague/ Black Death
> rat- reservoir host
flee- vector
transmitted through bite of an infected flea
Gram negative rod, non-motile
part of enterobacteriaciae family which are facultative anaerobes
virulence factors will have V and W antigens
> Bipolar Staining- safety pin appearance
Sporothrix schenkii
- subcutaneous fungi, not systemic fungi
> thermally dimorphic fungus that lives on vegetation
causes a chronic granulomatous infection
asteroid body is often seen in tissue samples that contains a central basophilic yeast cell
CIGAR-SHAPED yeast cell with asteroid bodies/cells
most reliable method of dx is culture
can mimic chronic cavitary TB in cases of primary pulmonary sporotrichosis
NOT TRUE: Tx of choice is saturates solution of KI in milk - give in thyroid storm
DOC: Itraconazole, Amphotericin B
Ampho can damage KIDNEYS (Tubules)- monitor electrolytes
Disease caused by S. schenckii
Rose Gardener’s disease
> Inoculation thru traumatic puncture
spread via lymphatics
Systemic mycoses characterized by the presence of multiple skin lesions known as DESERT BUMPS and can cause desert rheumatism:
Coccidioidomycosis
- North american/ chicago disease/ Gilchrist’s disease - Blastomycosis
- South american- Paracoccidioidomycosis
- Histoplasmosis- bat poop
- Desert valley fever/ Desert bumps/ desert rheumatism - coccidioidomycosis- associated with Erythema nodosum
Neurocysticercosis
> caused by Taenia solium
not T. Saginata-> Taeniasis; will only stay at the GI tract
corticosteroids for mgt
intestinal infections are usually asymptomatic, with mild intestinal symptoms that includes diarrhea and abdominal pain
NOT TRUE: acquired by eating cysticerci encysted in undercooked pork
- ingestions of T. Solium eggs (w/ radial striations surrounding the peripheri —> cysticercosis
- ingestion of larva/cysticercus—> Taeniasis
