bacteria basics Flashcards by L W

acute phase cytokines

IL-1
IL-6
TNFα

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hair-like structures that mediate adherence of bacteria to surfaces (respiratory, GI tract)

fimbriae

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forms attachment between 2 bacteria during conjugation

pilus

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pilus allows transfer of DNA (plasmids = resistance, virulence factors = toxins) from one bacteria to another

conjugation

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longer than fimbriae and pilus

provide whip-like motility

flagella

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gelatinous polysaccharide coat of bacteria

adds in attachment to foreign material (indwelling catheter, teeth)

glycocalyx

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if organized glycocalyx (polysaccharide coat) and firmly adherant to bacteria (sugar coat)

capsule

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if loosely adherant and less organized glcyocalyx (polysaccharide coat)
produced by bacteria
shields from antibiotics, hard to remove

slime/biofilm

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protects bacteria from phagocytosis

allows for time to evade immune system and divide

capsule (type of virulence factor)

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test to detect encapsulated bacteria:
anti-capsular serum added to bacteria
positive: capsule swells under microscope

quellung reaction

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encapuslated bacteria

SHiN
**Streptococcus pneumoniae
**Haemophilus 
influenza type B
**Neisseria meningitidis

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most vulnerable population to encapsulated bacteria infection

splenectomy patient
vaccinate against polysaccharide capsule (antigen):
**Streptococcus pneumoniae
**Haemophilus 
influenza type B
**Neisseria meningitidis

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yeast with capsule

cryptococcus neoformans

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ribosomes

location of protein synthesis

2 subunits combine to translate mRNA

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prokaryote (bacterial) ribosomes

70S (50S + 30S)

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eukaryote (human) ribosomes

80S (60S + 40S)

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genetic material separate from chromosomal DNA and
replicate separately
genes for: antibiotic resistance, enzymes, toxin production
transferred during conjugation

plasmids

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mechanisms of genetic change in bacteria

conjugation via pili and plasmids
transformation
transposition
transduction

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DNA released from lysed cell and then taken up by a living bacterium
DNA fragments incorporated into chromosomal DNA→recombinant bacteria

transformation

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what bacteria can acquire genetic material via transformation

SHiN
**Streptococcus pneumoniae
**Haemophilus 
influenza type B
**Neisseria meningitidis

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small segments of DNA that can self-exise and relocate
transfer from chromosome to plasmid (allow for AR, spread to another bacteria via conjugation) and vice versa, chromosome to chromosome
may carry antibiotic resistance, VFs

transposons

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bacteriophage (phage = virus that infects bacteria) attaches to bacterium and injects its DNA
phage DNA and proteins are repackaged in viral capsids -
some bacterial DNA also be in the viral capsid
new phage injects viral and bacterial DNA into next bacterium
bacterial DNA of virus + host can combine

transduction

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sterols in plasma membrane

NO cell wall

mycoplasma (bacteria)

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cell wall:
mycolic acid
high lipid content (resistant to gram staining)

mycobacteria

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dormant form of bacteria until hospitable environment is available, then replicate again resist: dessication, heat, cold, disinfectants, lack of nutrients

spores

bacteria that don't gram stain well

These Microbes May Lack Real Color: Treponema (G- corkscrew, too small to visualize) Mycobacteria (high lipid content in cell wall) Mycoplasma (no cell wall) Legionella pneumophila (branched fatty acids in cell walls, intracellular) Rickettsia (intracellular) Chlamydia (intracellular)

Giemsa stain

``` Honestly, Certain Bugs Really Try my Patience Histoplasma Chlamydia Borrelia Rickettsiae Trypanosomes my Plasmodium ```

periodic acid schiff (PAS) stain

``` PASs the sugar (stains gycogen + mucopolysaccharides) Tropheryma whipplei (Whipple's disease) ```

ziehl-neelsen stain

stain acid fast organisms: | mycobacterium tuberculosis

india ink stain

encapsualated yeast: cryptococcus neoformans

silver stain

fungi: pneumocystis jirovecii | legionella

provides rigid support to bacterial cell and protects against osmotic pressure differences

peptidoglycan layer of cell wall

spore-forming bacteria when nutrients limited or environment is inhospitable

G+ rods: bacillus, clostridium | others: coxiella burnetti

bacteria has to be in aerobic environment to grow and produce energy

obligate aerobe

obligate aneorobe bacteria

lack catalase and superoxide dismutase: G+: clostridium tetani, actinomyces G- rod: bacteroides

antibiotics for aneorbes

metronidazole | clindamycin

causes of neonatal sepsis

``` GBS E coli (G-) listeria monocytogenes (G+) ```

organisms most commonly implicated in subacute endocarditis

viridans group streptococci (most common cause of subacute infective endocarditis) enterococci s. bovis coagulase negative staph (s. epidermidis) HACEK organisms

most common cause of meningitis

s. pneumoniae

most common cause of ostoemyelitis

s. aureus

most common bacterial cause of otitis media in children

s. pneumoniae

cellulitis

s. aureus | s. pyogenes

associated with reactive arthritis (Reiter's syndrome)

``` G- diarrhea bugs: shigella salmonella campylobacter jejuni yersinia others: chlamydia trachamotis ```

infection associated with animal urine

leptospira (spirochete) | hantavirus (rodent urine)

diarrhea after raw eggs or raw chicken

G-: campylobacter salmonella

rice water stools

G-: vibrio cholerae ETEC

diarrhea from household pet

G- rods: yersinia enterocolitica salmonella (reptiles, pet turtles)

blood diarrhea after eating undercooked hamburger meat

EHEC

diarrhea + RLQ pain like appendicitis

yersinia

pregnant women should avoid unpasteurized milk due to these bacteria

listeria brucella species coxiella burnetti

most common bacterial cause of cervicitis

chlamydia trachomatis

antibiotic put on eyes after baby is born birth

gonorrhea conjunctivitis | doesn't treat chlamydia conjunctivitis (use oral azithromycin or erythromycin)

3 main causes of atypical pneumonia ("atypical")

legionella pneumophila chlamydophila pneumoniae mycoplasma pneumoniae

treatment for atypical pneumonia ("walking")

empiric treatment (don't look for bug) since antibiotic covers all: azithromycin doxycycline flouroquinolones

bacteria that are non-staining + culture poorly

gardernella vaginalis: bacteria vaginosis ricketssiae: Giemsa Ehrlichia chaffeensis: human monocytic ehrlichiosis Anaplasma phagocytophilum: human granulocytic anaplasmosis Coxiella burnetti: Q fever chlamydia species mycoplasma pneumoniae

if low glucose in CSF fluid consider

bacterial meningitis | tuberculosis meningitis

obligate intracellular bacteria

rickettsia coxiella chlamydia

catalase-positive organisms

``` S. aureus E. coli pseudomonas klebsiella aspergillus salmonella ↑ catalase + infections in chronic granulomatous disease (phagocytes lack free radicals to kill due to no NADPH oxidase) ```

mycobacteria that causes TB-like symptoms in COPD patients

mycobacterium kansasii

mycobacteria that causes cervical lymphadenitis in children

mycobacteria scrofulaceum

mycobacteria that causes disseminated disease in AIDs patients

MAI or MAC mycobacteria avium intracellulare mycobacteria avium complex

mycobacteria that causes hand infection in aquarium

mycobacteria marinum

obligate aerobe bacteria

``` Nagging Pests Must Breathe Nocardia Pseudomonas aeruginosa Mycobacterium tuberculosis Bacillus ```

characteristics of enterobacteriaceae in colonic flora

G-, facultative anaerobic bacteria (don't need O2) ferment sugar into lactic acid if excess in colon: can cause lactic acidosis due to absorption

function of MacConkey agar

isolates G- bacteria (crystal violet + bile salts inhibits growth of G+) distinguish lactose fermenters (pink) from non-lactose fermenters (white)

cell wall inhibitor effective against pseudomonas

3rd or 4th gen cephalosporins carboxypenicllin (like ticarcillin) aztreonam carbapenems

produce urease: hydrolyzes urea → ammonia →↑ pH of urine (more alkaline) → struvite stones (magnesium ammonium phosphate): "staghorn calculus"

proteus mirabilis | klebsiella