micro lab tessst

plate count

px: quantify # of bacteria in a dilution

pcdr: serial dilution. <30=TFTC, >300=TNTC

anything 2.9×10^5 is safe

uv light

px: efficacy of uv light for killing bacteria

pcdr: endospore forming bacteria (clostridium sp. bacillus sp.)

pros: efficiency + reach

cons: poor penetration

kirby bauer

px: which abx is strongest?

pcdr: mueller hinton lawn, place abx discs. check zone of inhibition (measure diameter in mm). compare to chart for sensitivity

ELISA

enzyme linked immunosorbent assay

antigen —> antibody

px: presence of target antibody

pcdr: antibody in well, wash well, add pt sample. if positive, antigen will bind to antibody. wash well, add anti-antigen w/ enzyme. wash well, add chromagen. enzyme cleaves chromagen, creating blue color (if postive).

indirect tests for antibodies, lifetime exposure

direct tests for antigens, current exposure

transformation

px: gene insertion to produce protein/whatever we want

pcdr: induce competency (CaCl2+heat shock), warm water bath 30 min. incubate

plasmid needs ori, promoter, gene, pfG, ampR

“satellite colonies” form around transformanta that spir out beta lactamase

Staphylococcus aureus

gram +

cocci / staph

commensal /opportunistic

nosocomial

mannitol salt+ / beta hemolysin / catalase+

most frequent:

skin: folliculits, impetigo, cellulitis, SSSS

eyes: conjunctivitis

gastrointestinal: food poisoning

genitourinary: TSS

MRSA, VRSA, MSSA

Escheria coli

Gram -

Bacilli (rods),

Motile

Enteric

Rapid lactose fermentation

most frequently:

Gastrointestinal: acute, traveler’s,

& chronic diarrhea, dysentery

Genitourinary: UTI

Less Frequent:

Respiratory: pneumonia - HCAP

Nervous: meningitis

Cardiovascular: sepsis,

hemolytic uremic syndrome

Streptococcus pyogenes

Gram +

Cocci

Strips

mannitol salt+ / beta hemolysin / catalase-

Group A Strep

Most Freq.:

Pharyngitis: strep throat

Sequelae: scarlet fever, rheumatic fever

Skin: impetigo, cellulitis

Eyes: conjunctivitis

Cardiovascular: sepsis, endocarditis

Psuedomonas aeruginosa

Gram -

Bacilli (rods)

Motile

Aerobic

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No carbohydrate fermentation

Oxidase +

Catalase +

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Most Frequent:

Skin: Burn patients

Respiratory:

Pneumonia - cystic fibrosis

Otitis Media

Chlamydia trachomatis

Gram ?

Cocci

Obligate intracellular bacteria (no ATP!)

Rare exception, no PG!?

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Giemsa stain, NAAT, or Sero test

Most Frequent:

Genitourinary: STI

Eyes: conjunctivitis

Neonatal: pneumonia / conjunctivitis

Neisseria gonorrhoeae

Gram -

Diplococci

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Can live extracellularly

Can live inside neutrophils (WBCs)

Gram stain or PCR

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Most Frequent:

Genitourinary: STI

Neonatal: pneumonia / conjunctivitis

Mycobacterium tuberculosis

Gram ? (thin PG)

Acid-Fast Stain

Strict aerobes

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Mycolic acid wax on surface

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Respiratory:

Pulmonary granuloma

= Caseous Necrosis

Lymph node granuloma

Lactobacillus acidophilus

Gram +

Bacillus (rod)

Commensal

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Reduces inflammation

Microbial antagonist

Enhance tight junctions

Commensal: lungs, vagina, GI

Gardnerella vaginalis

Gram variable!

Coccobacillus

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Etiology:

Lower pH (acid)

Lactobacillus = acidophile

G. vaginalis = alkaliphile

Higher pH (alkaline)

Detection:

1. pH or

2. Wet mount = clue cells

Genitourinary: bacterial vaginosis (BV)

*Not caused by yeast → yeast infection

*Not caused by protozoa → trichomoniasis

Not sexually transmitted

Clostridioides difficile

Gram +

Pleomorphic/polymorphic

Motile

Anaerobic

Nosocomial

Superinfection

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endospore forming

GI: diarrhea, collitis, pseudomembranous collitis

methanobrevibacter ruminantium

Archaea (not bacteria)

Prokaryote

Strict anaerobes

Coccobacillus

Live in rumen (ruminants)

produce CH4 from CO2

humman immunodeficiency virus

+ssRNA

Enveloped

Reverse transcriptase

Provirus

CD4+ T Cells (WBC)

Die of secondary infection due to low

T cells

Acquired Immunodeficiency Syndrome

influenza virus

- ssRNA (segmented)

Enveloped

Hemagglutinin (into cell, antibody

response)

Neuraminidase (release from cell)

candida albicans

Dimorphic Fungi

Human commensal

Opportunistic

Nosocomial

Yeast = Round large shape

Mold = Hyphae, pseudohyphae

Candidiasis:

Thrush - mouth

Yeast Infection - vagina

Invasive - bloodstream

Pulmonary - lungs

Cutaneous - skin

penicilium sp.

Mold (filamentous fungi)

Opportunistic

Small vesicle

Conidiospores

aspergillus sp.

Mold (filamentous fungi)

Aspergillosis

Opportunistic

Large vesicle

Conidiospores

Mildew

Black mold

dermatophytes

Molds (filamentous fungi)

Microsporum

Epidermophyton

Trichophyton

Sporangiospores

Not opportunistic

coccidioides sp.

Dimorphic fungi

Coccidiomycosis

Valley Fever

Opportunistic

Or high levels of exposure

South West United States

plasmodium falciparum

Protozoa causes malaria

Nonmotile

Cysts & Trophozoite:

Mosquito-borne

Biological vector

Develops in RBCs

Dormant in hepatocytes

giardia lamblia

Protozoa causes giardiasis “giardia”

Flagellated

Cysts: Fecal-oral transmission

Trophozoite: GI

trichononas vaginalis

Protozoa causes TV or “trich”

Flagellated

No cyst form

Trophozoite:

Vagina / Penis

toxoplasma gondii

Protozoa causes toxoplasmosis

Non-motile

1. Fecal-oral (farm animals, cats)

2. Undercooked meat, seafood

3. Vertical (mother to child)

ascaris lumbricoides

Helminth

Parasitic roundworms cause

ascariasis

Fecal-oral

Undercooked meat (larvae burrow)

enterobius vermicularis

Enterobiasis (pinworms)

Parasitic roundworms