Bacteria II Flashcards
Staphylococcys aureus
non-motile Gram + cocci, beta hemolytic
catalase +, coagulase +, oxidase +
VF: TSST-1, enterotoxins, exfoliative toxins,
Protein A, Staphylokinase, hemolysins
Staph. aureus illnesses
Rare: Scalded Skin Syndrome, enterocolitis, osteomyelitis
Common: pneumonia, UTI,
also: septicemia, bronchitis, food poisoning, atopic dermatitis
Staphylococcus epidermidis
gram + cocci, facultative anaerobe non-hemolytic, Catalase +, Coagulase -, *opportunistic pathogen --> biofilm treatment: vancomycin
Bacillus anthracis
gram + rod, non-motile, spore-forming;
non-hemolytic,
* “medusa head” appearance
VF: polyD glutamic acid capsule, EF (edema factor), LF (lethal factor), PA (protective Ag)
transmission: aerosolized spores, direct contact (in soil), ingestion
Bacillus anthracis illness
eschars/lesions, Gram - shock (if ingested)
- pulmonary anthrax: lethal! fever, non-prod. cough
- cutaneous anthrax: papule -> ulcer -> eschar
- GI anthrax: ulcers in throat, bull neck, respiratory failure
treatment: tetracycline, ciprofloxacin, clindamycin, IVIG
Bacillus cereus
gram + rod, non-motile, spore-forming;
Hemolytic & stick together end-end.
transmission: aerosolized spores, traumatic implantation, or ingestion
Bacillus cereus illness
#1: food poisoning --> diarrhea +/- vomiting; rare: necrotizing fasciitis
treatment: nothing
All mycobacteria (tuberculosis, bovis, leprae)
Acid fast rods w/ waxy outer coat,
non-motile, no spores, catalse +
VF: Wax D and mycobactin. (no capsule or toxins)
* + cord factor and tuberculin for M. tuberculosis*
Tuberculosis
from mycobacterium tuberculosis or bovis;
transmission: aerosols or direct contact,
- -> fever, granulomas, tissue damage/necrosis
treatment: HRZE (Isoniazid, Rifampin, pyraZinamide, Ethambutol), cycloserine, aminoglycosides, some quinolones
* MANY resistant strains!
Leprosy
from Mycobacterium leprae,
- Tuberculoid: few erythematous lesions, loss of sensation
- Lepromatous: (no more immune response) total loss of sensation –> limb loss, blindness, waxy nodular lesions
Treatment: #1 dapsone, & clofazimine, rifampin, thalidomide
streptococcus pyogenes (grp A)
gram + cocci, non-motile facultative anaerobe;
bacitracin sensitive, beta hemolytic, catalse -, lac +
VF:
- surface: M protein, C5a peptidase, hylal. capsule, IgA/G Fc BPs
- secreted: superAgs, Streptolysin O/S, streptokinase
Strep. pyogenes (grp A) illness
1: strep throat
Also: impetigo, scarlet fever, acute glomerulonephritis, TSS, rheumatic fever
Treatment: penicillin, azithromycin, clindamycin, IVIG for TSS
Streptococcus agalactiae (grp B)
gram + cocci,
beta hemolytic, catalse -
VF: polysac. capsule, C5a peptidase, surface proteins A/B
Strep agalactiae (grp B) illnesses
neonatal: meningitis, sepsis
Adults: pneumonia, meningitis, osteomyelitis, otitis media
- treatment: penicillin
Streptococcus pneumoniae
gram + cocci, aerotolerant anaerobe;
* part of normal flora
– optochin sensitive, catalase -, alpha hemolytic;
VF: polysac capsule, sIgA protease, pneumolysin, PspA
Streptococcus pneumoniae illness
1: pneumonia
also: meningitis, endocarditis, otitis media
treatment: steroids (anti-inflam.) + antibiotics
* commonly penicillin-resistant
Clostridium tetani
gram + rod, spore forming (tennis racket-shaped), highly motile ANaerobe; Catalase -, oxidase -
VF: tetanospasmin (AB exotoxin), alpha toxin, alpha hemolysin
transmission: traumatic implantation of spores (ie: from soil)
tetanus
–> spastic paralysis, death from respiratory failure
Treatment: IGIV w/ toxin Ab, benzodiaszepines, control airway
Prevention: toxoid vaccine
Clostridium difficile
gram + rod, forms heat-resistant spores, Anaerobe;
Catalase -, oxidase - *nosocomial
VF: TcdA and TcdB toxins
Clostridium difficile illness
- -> pseudomembranous colitis, severe diarrhea
- when competing bacteria = wiped out by penicillin or clindamycin*
treatment: fecal transplant
Clostridium botulinum
gram + rod, Anaerobe, forms heat-resistant spores;
catalase -, oxidase -;
VF: botulinum toxin –> cleaves synaptobrevin (blocks ACh binding to NMJ)
Botulism
–> hypotonia, weakness/paralysis, ptosis and diplopia, dry mouth
transmission: canned foods, honey (infants)
Treatment: antitoxin, ventilate, human/horse IVIG, no antibiotics
Bordatella Pertussis
non-motile gram - coccobacillus;
* diagnose w/ ELISA
VF: Adenylate cyclase toxin, pertussis toxin, FHA (fil. hemagglutinin), fimbrae & pertactin
Whooping cough/pertussis
caused by bordatella pertussis; = violent cough
transmission: aerosol
stages:
1. Catarrhal: infectious (1-2 wks) ==> erythromycin, ceftriaxone
2. Paroxysmal: cough, antibiotics don’t help
3. convalescent: secondary infections (3-4 wks)
Haemophilus influenzae
gram - coccobacillus, facultative anaerobe;
* HiB = most pathogenic serotype
— grows on chocolate agar
VF: capsule, LOS, heme receptor, sIgA protease
Haemophilus influenzae illnesses
Childhood – meningitis
Adult – bronchitis/pneumonia, otitis media, conjunctivitis
Treatment: Cefuroxime, azithromycin, augmentin, trimeth/sulfam.
Prevention: Hib vaccine
Neisseria meningitidis
gram - diplococcus, non-motile microaerophile;
Oxidase +,
VF: capsule – blocks MAC, IgG and phagocytosis
& endotoxin, IgA protease
meningitis (disease)
headache + fever, stiff neck, petechial rash,
–> DIC and gram - shock
Dx: cloudy, infected CSF; purpura
transmission: saliva droplets
treatment: Penicillin G, cephalosporins, dexamethasone,
** prophylactic Rifampin if exposed!
Neisseria gonorrhea
gram - diplococci, motile microaerophile;
– grows on chocolate agar,
VF: pili, LOS, IgA protease, highly varying Ag
Gonorrhea
–> yellow, purulent discharge OR opthalmia neonatorum
** find diplococci IN PMNs!
treatment: ceftriaxone + azithromycin
rapid test: for Ags in discharge
Legionella
doesn’t gram stain –> use Dieterle silver stain;
motile w/ polar flagellum;
= facultative intracellular pathogen.
VF: MIP, DotA, LPS, endotoxin, beta-lactamase
Legionella illness
- severe acute pneumonia: headache, high fever, diff. breath
- pontiac fever: mild, flu-like
transmission: via aquatic amoebae
treatment: none
- pontiac fever: mild, flu-like
listeria monocytogenes
gram + coccobacillus, motile (via actin),
catalase +
VF: internalin, listeriolysin O (escape phagosomes), actin motility (can move to infect more cells)
listeria monocytogenes illness
listeriosis, meningitis, neonatal sepsis, encephalitis!
- mostly in immuno-compromised (ie: babies)
transmission: contaminated dairy/produce, Vertical (mom-baby)
treatment: Penicillin G, ampicillin, erythromycin, tetracycline
Heliobacter pylori
motile, gram - curved rods, microaerophilic;
VF: urease
Heliobacter pylori illness
nausea and abdominal pain, peptic ulcers + vomiting, bleeding;
gastroenteritis, Cancers! (MALT lymphoma, gastric adenocarcinoma)
Transmission: oral ingestion
Treatment: triple therapy (2 antibiotics + proton pump)
** socioeconomic association, bacteria = present in most ppl**
Campylobacter spp.
motile gram - S-shaped rod, microaerophilic;
nitrate reductase +, catalase +, oxidase +
** resistant to vancomycin, trimethoprim, polymyxin B**
VF: LPS, adhesins
Campylobacter jejuni illness
C. jejuni: dysentery and self-limiting gastroenteritis,
* Guillain-Barre = post-inf. complication transmission: fecal-oral (lamb castration) treatment: No antibiotic or macrolides
Campylobacter fetus illness
(rare) septicemia in newborns or immunocompromised,
or miscarriage;
transmission: fecal-oral/opportunist
treatment: hydration and electrolyte replacement, no antibiotics
Shigella
gram - rod, only inter-cellular motility, non-spore forming;
Lac -, oxidase -, facultative anaerobe.
intracellular, 4 types of O Ag
VF: shiga toxin (inactivates protein synth),
Shiga toxin mech.
depurinates 60S subunit of ribosome
–> inactivate protein synthesis
==> Hemolytic uremic syndrome
Shigella illness
infects large intestine –> dysentery/bloody diarrhea (+/- pus);
transmission: fecal-oral *low infectious dose!
(flies, fomites, fingers, food, feces)
Treatment: self-limiting, monitor dehydration
Salmonella
motile gram - rod, non-spore forming; Lac -, oxidase -, facultative intracellular pathogen, NOT part of normal flora. (invades B cells, PMNs, macrophages) VF: LPS
Salmonella illness
infects small intestine –> high fever, gram - shock, petechia (rose-colored), DIC (=typhoid fever); + gastroenteritis and sepsis
transmission: fecal-oral, esp. via cheese!
treatment: control shock, ampicillin or chloramphenicol for sepsis
Bugs causing food poisoning
Contaminated seafood: Vibrio spp.
Reheated rice: Bacillus cerus
Meats, mayonnaise, custard: S. aureus
Reheated meat dishes: Clostridium perfringens
Improperly canned foods: Clostridium botulinum
Undercooked meat: E.Coli (EHEC, O157:H7)
Poultry, meat, eggs: Salmonella
Vibrio cholerae
gram - curved rod, facultative anaerobe, highly motile;
oxidase + (not enterobacteriaceae)
VF: cholera toxin
Cholera toxin mechanism
(AB toxin) A binds to & activates Gs –> increase cAMP
–> block Na+/K+ pump and hypersecrete K+, Cl-
–> massive fluid loss into lumen
==> watery diarrhea
cholera (illness)
“rice-water diarrhea,” hypovolemic shock, nausea, vomiting, cramps
transmission: fecal-oral (H2O contamination) + algal blooms (seafood)
treatment: fluid and electrolytes, no antibiotics
vibrio spp.
motile gram - curved rod, facultative anaerobe;
a) parahaemolyticus: contam. shellfish –> diarrhea, self-limiting
b) vulnificus: diarrhea, + cellulitis –> sepsis (lethal)
Escherichia coli
motile gram - rod, fac. anaerobe, extracellular pathogen
Lac + (pink on Mac plate)
VF: LPS, Shiga-like toxin (ADP ribosylation)
E. coli illnesses
gram - shock, UTIs, neonatal meningitis
- ETEC: traveler’s diarrhea/cholera
- EIEC: bloody diarrhea
- EHEC: copious bloody diarrhea, Hemolytic uremic syndrome
- EPEC: watery/bloody diarrhea * treat w/ trimeth/sulfameth!
Transmission: fecal-oral, endogenous
treatment: peptobismol
Francisella tularensis
gram - rod, fac. intracellular pathogen (macrophages);
grows slowly on BAP,
VF: antiphagocytic capsule, –> host cell apoptosis
endotoxin –> gram - shock
tularemia illness
(by francisella tularensis)
high fever, headache, lymphadenopathy, conjunctivitis (~typhoid)
transmission: infected rabbit contact, tick/deerfly/mosquito bites
treatment: aminoglycosides (or ciprofloxacin + doxycycline)
ie: streptomycin, gentomycin
yersinia pestis
gram - coccobacilli, fac. anaerobe, intracellular pathogen (macrophages);
oxidase -
VF: biofilm, endotoxin
“the plague” (yersinia pestis infection)
transmission: bites from infected fleas
a) bubonic: homorrhagic buboes in lymph nodes, fever/chills, etc.
gram - shock;
b) pneumonic: (bubonic)–> spread to lungs, *aerosol spread!
“white out lungs,” gram - shock;
c) septicemic: (bubonic)–> abnormal coagulation => gangrene
treatment: Aminoglycosides, doxycycline, fluoroquinolones
*must treat pneumonic w/in 24 hrs!
Pseudomonas aeruginosa
motile gram - rod, aerobe;
oxidase +, grows on PAP plates
VF: biofilm, LPS, Exoenzyme S (impairs phagocytes) and Exotoxin A (ADP-ribosylates –> inhibit protein synthesis)
Psuedomonas illness
bacteremia (anywhere in body) - pneumonia, abscesses, UTI, sepsis * CF colonization by age 10
transmission: hospital
treatment: gentamycin & carbencillin (super resistant to b-lactams, quinolones, etc.)
Burkholderia cepacia + illness
motile gram - rod;
nosocomial, *co-infects w/ pseudomonas aeruginosa in CF pts
VF: biofilm, eats penicillin
treatment: trimeth/sulfameth. or chloramphenicol
(high antibiotic resistance)
Mycoplasma pneumoniae + illness
No cell wall, won’t gram stain
- -> small colonies (NOT fried egg look)
illness: atypical/walking pneumonia (fatigue, sore throat, fever, non-productive cough)
treatment: erythromycin, tetracycline
Borrelia bergdorferi
Gram - spirochete, aerobe
- identifiable by ELISA
VF: LPS
* gravitates to joints, skin and CNS
Lyme disease
caused by transmission of borrelia bergdoferi from ixodes tick;
–> erythema chronica migrans (bulls eye rash),
+ neurologic, muscular, cardiac sequelae
treatment: ceftriaxone + doxycycline
Borrelia hermsi and illness
gram - spirochete, motile aerobe; * use Giemsa stain VF: LPS, varying Ag (resists opsonization) --> recurrent fever transmission: lice.
leptospira interrogans
gram - spirochete w/ hooked ends,
VF: hemolysin
transmission: via animal urine (through human skin/mucus membrane)
leptospira interrogans illness
- -> Leptospirosis (Biphasic)
1. septic phase: fever, chills, head and muscle ache
2. immune phase: nausea, vomiting, meningitis
3. chronic phase: jaundice, renal failure, endocarditis - esp. in soldiers, sewer workers, veterinarians **
treponema pallidum
motile spirochete, aerobe;
visible by darkfield microscopy
VF: LPS endotoxin, hyaluronidase
syphilis
primary: contagious; painless chancre
secondary: contagious; fever, sore throat,
** + rash on palms and soles of feet! **
tertiary: NOT contagious; neurosyphilis, gummas on skin
(chronic: placental transfer –> blindness, etc.)
Treatment: penicillin …but: Jarish-Herxheimer rxn (worsen w/drug)
Chlamydia trachomatis
non-motile gram Neg.;
obligate intracellular pathogen of epithelial cells,
can live in macrophages but not PMNs
- use Giemsa stain or IF
VF: LPS ** NO capsule!
Chlamydia infection
STD: urethritis, dysuria, pain, discharge, vaginal bleeding, pelvic inflam. disease;
-> Lymphogranuloma venereum
– Complications: sterility, Reiter’s syndrome
OR: Ocular trachoma
treatment: #1 doxycycline; or erythromycin and azithromycin
lymphogranuloma venereum
(from Chlamydia trachomatis)
quickly healing genital papule, fever, myalgia, and
lymphadenopathy (swollen inguinal lymph nodes)
Reiter’s syndrome
a complication of chlamydia trachomatis infection,
- -> triad:
1. conjunctivitis
2. urethritis
3. arthritis
chlamydia pneumoniae
gram neg. obligate intracellular pathogen,
* survives in macrophages but not PMNs
VF: LPS
walking pneumonia
aka: atypical pneumonia,
from chlamydia pneumoniae or mycoplasma;
–> non-productive cough, headache, fever – lasts several weeks
Treatment: #1 doxycycline, or erythromycin
life cycle of an Obligate Intracellular Pathogen
- Elementary Bodies (infectious) attach to epithelial cell(s)
- enter cell, establish phagosome –> Reticulate Body
(metabolically active, not infectious) - RBs replicate (~30 hrs)
- RBs condense back into EBs
- EBs kill and lyse cell –> release progeny to infect more cells
Chlamydia psittaci + illness
obligate intracellular pathogen of epithelial cells
* can live in macrophages but not PMNs
VF: LPS
= “parrot fever” - from bird droppings
–> like severe influenza (fever, non-productive cough, headache, sore throat) + hepatosplenomegaly
treatment: doxycycline, but 20% fatal!
ricketsia
small gram Neg., actin-motility,
obligate intracell. pathogen;
VF: LPS endotoxin, hemolysin
Ricketsia illness
- Spotted fever: from ticks and mites,
fever/chills/head & muscle aches;
then rash starting in feet, spreads to trunk - Typhus: from lice, fleas;
rash begins on trunk and spreads peripherally
treatment: tetracyclines + chloramphenicol, quinolones, supportive therapy
Erhlichia
small gram - cocci,
obligate intracellular pathogen of Leukocytes
VF: LPS endotoxin, hemolysin
Erhlichia illness
- -> fever/headache/myalgia, rash less common.
- 5-10 day incubation after bite!
transmission: deer and dog ticks (carry vectors) - death = from secondary infection (ie: pneumonia)
treatment: doxycycline
Coxiella burnetti
small gram - cocci,
intracellular pathogen of macrophages, replicate in phagosomes;
VF: LPS endotoxin, hemolysin
–> “Q fever”
Q fever
–> fever/headache/myalgia, etc. + endocarditis
* from coxiella burnetti
Transmission: animal-human aerosol
treatment: doxycycline
bartonella + illness
small gram - cocci, EXTRAcellular, infects RBCs;
–> angiomatosis, peliosis, endocarditis
“trench fever”/”cat scratch fever”/”bartonellosis”
transmission: fleas, lice, sand flies
treatment: doxycycline
