G^- bacilli, ferments lactose, fast fermenter, indole +

enteritis (watery or dysentery), UTI, pneumonia, neonatal meningitis, septic shock

Hemolytic Uremic Syndrome 

TMP-SMX, penicillin (UTI), 3rd gen cephalosporin (meningitis, sepsis)

O antigen (outer, LPS)

K antigen (capsular, PS)

H antigen (flagella, protein)

Pili/Fimbriae

Type III secretion system

resistance to serum killling

sequestation of growth factors

"rice water" diarrhea, ↑cAMP  by ribosylating adenylate cyclase, prevents sodium and chloride absorption into epithelial cells

E. coli O157:H7 produces Shiga-like toxin → HUS

G^- bacilli, ferments lactose, fast fermenter, "currant jelly sputum", indole - urase +

pneumonia (RUL), wound and STIs, UTIs

STD: Granulomatis (formerly Donavania granulomatis/Calymmatobacterium inguinale) uncommon in US

3rd gen cephalosporin

among the most drug resistant microbes causing nosocomial infections

can be mistaken for TB 

Alcoholics, Abscesses, Aspiration

polysaccharide capsule (K antigen) prevents phagocytosis unless opsinization has occurred by complement or IgG

sideophores take up iron from host

O atigen (lipopolysaccharide) 

G^- bacilli, lactose non-fermenter, oxidase -, urease +

UTI, "struvite" stones, nosocomial infecitons

Sulfa (TMP-SMX) or ampicillin 

fishy odor, ↑ urine pH

part of normal gut flora

G^- bacilli, lactose fermenters

hospital acquired infections

Enterobacter is very motile

Citrobacter koseri causes meningitis and brain abscess in neonates

G^- bacilli, lactose non-fermenter, oxidase -, non-motile, no H₂S production

dysentery (bloody diarrhea), tenesmus 

re-hydration, fluoroquinolones for severe cases (toxin mediated)

humans are the only reservoir (fecal-oral), intracellular pathogen

Shiga toxin A/B

S. flexneri & S. boydii are found primarily in Asia, Africa, and Central and South America, and cause a similar disease process 

S. sonnei is found in North America and causes watery diarrhea

G^- bacilli, lactose non-fermenter, oxidase -, non-motile, produce H₂S

Typhoid Fever: enlarged spleen, tender abdomen with red macules, diarrheea, diffuse necrotic lesions

Carrier State: stored in gallbladder, can present as necrotizing cholecystitis

humans are the only reservoir (fecal-oral)

avoid antibiotics and give supportive care if possible, ceftriaxone for reistant strains, cipro/amp for carriers, cholecystectomy may be required for carriers, killed and live-attenuated vaccines are available

patients with impaired gastric secretions are more susceptible 

G^- bacilli, lactose non-fermenter, oxidase -, non-motile, produce H₂S

S. typhimurium: diarrhea (sometimes bloody)

S. choleraesuis: sepsis

ABX not recommended for gastroenteritis

G^- bacilli, lactose non-fermenter, bipolar staining (safety pin appearance)

plague: fever, dark black skin patches (bubo), enlarged painful lymph nodes

carried by rodent fleas (prairie dogs, rats, etc)

stretomycin, tetracycline, chloramphenicol, TMP-SMX, vaccine (not available to general public), antibodies

can aerosolize (Pneumonic Plauge)

Murine Toxin (COD)

coagulase and fibrinolysin help destroy tissue

plasminogen activator degrades complement

TIII secretion system

G^- bacilli, lactose non-fermenter, motile at 25°C and not at 37°C

encterocolitis (bloody diarrhea), mesenteric adenitis, septicemia, arthritis, intra abdominal abscesss, hepatitis, osteromylitis, can mimic appendicitis 

raw milk, fecal-oral (humans and dogs)

Y. pseudotuberculosis reservoir - birds (rare in US)

G^- vibrios, lactose non-fermenters, oxidase +, Glc fermenter

"rice-water" diarrhea and dehydration

IV and oral rehydration therapy, tetracycline, vaccines available (not very effective)

cholera toxin (AB₅ toxin) is carried on phage

ribosylates G_s, ↑ cAMP

accessory cholera enterotoxin ↑ fluid secretion

Zonula occludens toxin ↑ intestinal permeability

Blood group O more vunerable

G^- vibrios, lactose non-fermenters, oxidase +, Glc fermenter, β-hemolytic, grows on 8% NaCl

mild self-limiting diarrhea to severe gastroenteritis

more invasive than cholera, may cause fever

associated with consuming raw seafood

G^- vibrios, fermentor, facultative anaerobe, salt requirement

wound infection, septicemia (secondary necrotic tissues)

wounds contaminated with seawater, raw oyster consumption

persons with pre-existing liver conditions are at higher risk

polysaccharide capsule and hydrolytic enzymes increase virulence

Aeromonas hydrophilia and A. caviae also cause wound infections similar in presentation to V. vulnificus 

ABX required

G^- bacilli seen in pairs, lactose non-fermentor, oxidase +, Glc non-fermentor, blue-green colonies, fruity odor, obligate aerobe 

pneumonia, septicemia, endocarditis (IV drug users), UTI, osteomyelitis (DM, IV drug users), burn wound infections,  malignant external ostitis (DM), folliculitis (hot tubs), many others!!!

Very ABX resistant, use a combination of ABXs, anti-pseudomonal PCN + aminoglycoside, fluoroquinolones, others

found in soil, water, and decaying matter

nosocomial infection

persons with CF may be colonized with non-invasive Pseudomonas 

neuraminidase, initial infection

Exotoxin A - similar to diptheria toxin, inhibits protein synthesis, dermatonecrosis in burn wounds, corneal damage in eye infection, immunosuppresive properties

TIII secretion system

biofilms

elastases, proteases, phospholipase C, rhamnolipids (hemolysin)

G^- bacilli, aerobic, non-fermenting 

Burkholderia cepacia - respiratory infection in CF patients, UTI, sepsis

B. pseudomallei - opportunistic pathogen, endemic to SE Asia, India, Africa, and Australia, localized cutaneous infections, mild bronchitis to necrotizing pneumonia

possible biological weaponn

G^- bacilli, aerobic, non-fermentive 

defibrillated patients, previously treated with broadspectrum ABX, found in ICUs

indwelling catheters or other medical devices

bacteremia, meningitis, pneumonia, wound infections

difficult to kill

G^- pleomorphic bacilli, non-motile, aerobic 

specifically targets moist tissues: mucous membranes, respiratory tract, SSTIs, UTIs, surgical wounds

resistant to most antibiotics

potential therapies: phage, bactericdal gene transfer, photodynamic therapy, nanoparticle therapy

risk factors: abx exposure in the last 90 days, previous deployment in dry sandy conditions, recent procedures

OmpA (outer membrane protein A)

biofilm formation

G^- "S-shaped" vibrios, urease -, oxidase +, non-fermentor, motile 

bloody diarrhea, secretory diarrhea, crypt abscess, Guillain-Barré Syndrome (damage to myelin sheaths due to antigen cross-reactivity), C. fetus dissemination and sepsis 

zoonotic: poultry, cattle, dogs, domestic animmals (fecal-oral, raw milk)

most are self limiting, rehydration therapy, erythromycin, ciprofloaxcin

may be misdiagnosed as Crohn's or ulcerative colitis (fastidious)

persons with impair gastric secretions are higher risk

Enterotoxin

Adhesin

Cytotoxin

Protein S (serum resistance)

G^- spirochete, urease +, motile (multiple polar flagella)

gastric and duodenal ulcer, gastric cancer and MALT lymphoma 

treat with a combination of antibiotic and antiacid therapy: macrolide, β-lactam, PPI, c or s bismuth

humans are primary reservoir

coevolution to an extent, many asymptomatic carriers

 abx and better hygiene → ↓ infection rate ↓ gastric cancers ↑ GERD ↑ esophageal

mucinase

phospholipase

urease 

cagA (associated with cancer, integrates into host cell DNA)

G^- diplococci, Glc only oxidizer, grows on chocolate agar and VCN (Thayer-Martain, Martin-Lewis), oxidase +

localized STI, septic arthritis

PID, ectopic pregnancy, sterility, Fitz-Hugh-Curtis Syndrome, can disseminate and cause arthritis, dermititis, endocarditis, and perihepatitis

ceftriaxone or azithromycin (+ doxycycline, tetracycline or azithromycin for probable concurrent Chlamydia infection), prophylactic erythromycin, silver nitrate, or tetracycline eye drops for neonates

humans are the only carriers

Rmp protein blocks antibodies

PorB inhibtis neutrophil degranulation

IgA Protease

becoming increasingly abx resistant

antigenic variation prevents immunity development 

G^- diplococci, Glc & Mal oxidizer, Thayer-Martain, Martin-Lewis agar (VNP), fastidious 

meningococcemia with petechial rash, meningitis

PCN, ceftriaxone (may exacerbate, give supportive care)

prophyalxis: rifampin, ciproflaxacin, or ceftriaxone, vaccine

major cause of meningitis in close living quarters, especially in young people (neonates are covered up to 6 months by passive maternal immunity, #2 cause in children)

dry sandy conditions interfere with innate immunity ,

5-10% population carries

LOS - lipooligosaccharide, potent endotoxin that cuases petechiae

Rmp protein blocks antibodies

PorA and PorB inhibti neutrophil degranulation

IgA Protease

polysaccharide capsule - antiphagocytotic 

G^- diplococci, fastidious, non-motile, oxidase +

otitis media, sinusitis, pneumonia

test for susceptibility

cephalosporins, erythromycin, tetracycline, TMP-SMX

opportunistic pulmonary invader 

G- coccobacilli, grown on chocoate agar

conjucntivitis, Brazillian Purpuric Fever

Tropical and subtropical distributionn

Haemophilus aphrophilus

Actinobacillus actinomycetemicomitans

Cardiobacterium hominis

 Eikenella corrodens

Kingella Kingae

part of normal oral flora and can infect heart values, most common cause of subacute endocarditis in non-IV drug users

G^- facultative anaerobe

normal flora of the mouth

can cause subacute endocarditis

G^- facultative anaerobe

colonize the mouth

periodontitis, endocarditis, bite wound infections

ampicillin

G^- facultative anaerobe

normal flora of the upper respiratory tract

can cause subacute endocarditis correlating with previous dental work

PCN or ampicillin

G^- bacilli, fastidious, eats pits in agar, bleachlike odor

opportunistic infection, normal oral flora

human bite wounds or fist fight injury

endocarditis, sinusitis meningitis, brain abscess, lung infection 

G^- bacilli

opportunistic infection, normal oral flora

septic arthritis in children, endocarditis all ages

β-lactams, tetracyclines, erythromycin, fluoroquinolones

G^- coccobacilli, grown on chocoate agar, + Quellung test, growth factors (V & X) needed

epiglottitis, meningitis (encapsulated Type B strain #1 cause in children), otitis media, pneumonia, sepsis and septic arthritis in asplenic patients 

β lactam, ceftriaxone, prophylaxis: rifampin 

Vaccine available for Type B strain capsule with diphtheria toxin, given at 2-18 months. 

Factor 5 (nicotenamide added to chocolate agar)

aerosol

polysaccharide capsule, asplenic patients are at higher risk

endotoxin

H. parainfluenzae causes similar infection

G- coccobacilli, grown on chocoate agar

STI, painful chancroid

erythromycin, ceftriaxone

H. paraphrophilus - endocarditis

H. haemolyticus - respiratory tract infections

G^- coccobacilli, "safety pin" appearance, grown on sheep's blood agar, catalase +, oxidase +

cellulitis, osteomyelitis, chronic pulmonary disease, hemorrhagic septicemia, meningitis, brain infection, septic arthritis, hepatitis

PCN, amoxicillin and clavulanic acid, or fluoroquinolone or tetracycline

animal bites and scratches, especially cats

G⁺ bacilli, spore-forming (terminal, "tennis racket" appearance), obligate anaerobe, motile

spastic paralysis, lockjaw, risus sardonicus, opsithotonus, death due to asphyxiation

clean wound, antitoxin, DTaP, PCN/metronidazole, diazepam (GABA agonist)

tetanospasmin: plasmid mediated, AB toxin blocks release of inhibitory neurotransmitters → tetnus

tetanolysin: hemolysin

natural immunity does not occur

G⁺ bacilli, spore-forming (terminal, "tennis racket" appearance), obligate anaerobe, motile, "mouse test"

Adult botulism: acetylcholine release blocked, diplopia, dysarthria, dysphagia, descending paralysis, dizziness, dry throat, ptosis

Infant botulism: constipation, flaccid paralysis

No fever (non-invasive) 

antitoxin & respiratory support, metronidazole or PCN for adults 

G⁺ bacilli, spore-forming (terminal, "tennis racket" appearance), obligate anaerobe, motile

pseudomembran colitis (PMC), diarrhea

oral metronidazole and/or vancomycin, withdrawal of causative ABX (often clindamycin)

enterotoxin/toxin a: alters fluid secretion → watery diarrhea

cytotoxin/toxin b: cytotoxic to epithelial cells → pseudomembranes (yellow-white plaques)

G⁺ bacilli, spore-forming, obligate anaerobe, boxcar shaped, non-motile

cellulitis, gas gangrene (myonecrosis), food poisoning (meats, meat products, gravy) - diarrhea and abd pain (type A)

early signs of necrosis include pain out of proportion to physical signs, a feeling of heaviness at the site of injury, and white, shiny tense skin

surgical debridement, hyperbaric oxygen, PCN and clindamycin are only effective in local, weak infections

Enteritis necroticans: necrosis of small intestine caused by β-toxin release, type C (common in New Guinea following ingestion of pork, 40% mortatility)

α-toxin (lecithinase) also causes tissue necrosis

G^- pleomorphic coocobacilli, obligate anaerobe, foul smelling, bile resistant

peritonitis, GI or pelvic abscesses

drain abscess, repair lesions, ABX (eg. metronidaxole, clindamycin, imipenim)

resistant to kanamycin, vancomycin, and colistin

most common among normal GI flora

makes vitamin K

number 1 cause of anaerobic infections, and most resistant

G⁺ beaded filaments, not acid fast, obligate anaerobe, yellow sulfur granules

slowly developing infection, abscesses in mouth, lungs, GI tract, GU tract, draining sinus tracts

PCN G for 4-12 months, surgical drainage of abscesses

normal GI & GU flora, infection usually occurs following trauma and surgery

G^- anaerobic spirochete, cannot be cultured (except in rabbit testes), VDRL test (should be verified) or FTA-ABS detection

syphilis: painless ulcers (chancre) on genitals progressing to flulike symptoms (Jarisch-Herxheimer Reaction), disseminated rash, and hepatitis, and finally to gumma in organs and skin (neuro involvement) if left untreated

can be passed congenitally resulting in abortion or stillbirth (white pneumonia)

PCN (DOC), tetracycline, or erythromicin

Can't survive outside of human host

hyaluronidase - promotes invasion, adherence, and immmunopathogenesis

Fibronectin coating

G^- anaerobic spirochete, immunological cross reaction for venereal syphilis

Yaws: skin and bone infection T. pallidum subsp. pertenue

Pinta: skin infection T. carateum

Bejel: skin, bone, and mucous membrane (primarily mouth) infections T. pallidum subsp. endemicum

G^- spirochete, motile, darkfield, Giemsa or Wright staining

Lyme disease: recurring fever, erythema chronicum migrans (Bull's eye rash); bacteremia: high fever, chills, muscle aches and headache; late signs: meningitis, encephalitis, cardiac dysfunction, arthralgia and arthritis

Lyme: amoxicillin, tetracycline, doxycycline or cefuroxime (early) or ceftriaxone or PCN (late); relapsing fever: tetracycline or erythromycin

transmitted by deer tick, Ixodes (reservoirs include white footed mouse and white tailed deer)

B. hermsii, B. turicatae, and B. parkerrii also cause relapsing fever, and are transmitted by tick and lice

blood sample must be taken during febrile period to demonstrate infection; during the afebrile period, enlarged organs (eg. liver, spleen) are seen

G^- spirochete, visible with darkfield 

leptospirosis can be asymptomatic; Fort Bragg Fever, Swineherd's Disease, Conjunctivitis, Weil's Syndrome, Infectious Jaundice

PCN or doxycycline

Animal reservoir, animal urine, cats, dogs, livestock

vaccine available for livestock

G^- pleomorphic coocobacilli (G stain poorly, visualized with silver stain or with fluorescence), catalase +, growth on charcoal yeast agar with iron and cysteine, "ground glass colonies", nodular infiltrates on CXR (often takes several months to resolve), facultative intracellular parasite (vacuole), 2-10 day incubation in host

Pontiac fever (flu-like, aggressive spread,self-limited) Legionnaire's disease (pneumonia or gastroenteritis, requires ABX, 15-20% mortality, smokers >60 yo and immunocompromised are high risk) 

Respiratory fluoroquinolone or macrolide; prophylaxis: copper-silver ionization 

water reservoirs, feeds on decaying animal and plant matter, can live in amoeba and macrophages

poorly staining short G^- bacilli (use silver), fastidious

B. henselae - Cat Scratch Fever, regional lymphadenopathy, fever of unknown origin, ocular involement, hetaosplenomegaly

B. quintana - Trench Fever, fever, bacillary angiomatosis, and endocarditis, recurrent 5 day attacks, transmitted by the human body louse, still seen in the homeless and immunocompromised

B. bacillliformis - Carrion's Disease, transmitted by sand flies in Andes, Oroya fever followed by veruga peruana (skin lesions), takes 30-60 days to resolve

azithromycin or doxycycline (reserve for immunocompromised), consult for current therapies

does not Gram stain, can only be seen by electron microscopy, "cold agglutinins" (nonspecific), "fried egg" colonies on Eaton's agar after a few days, fastidious with long incubation period

Early: fever, malaise, headache, pharyngitis, cough, tracheobronchitis; Late: primary atypical pneumonia ("walking pneumonia"), neurologic, pericarditis, hemolytic anemia, arthritis, mucocutaneous lesions, slow recovery

macrolide (azrithromycin, erythromycin, etc.)

children and the immunocompromised are at risk

can only be seen by electron microscopy

M. gentalium - pyelonephritis, PID, post-partum fever, systemic infection

M. hominis & U. urealyticum - non-gonococcal urethritis, pneumonia and premature delivery in neonates

obligate intracellular parasite, detectable by PCR

STD, men - urethral discharge, epidiymitis, non-painful ulcer, painful swollen lymph nodes, anal infection; women - cervix and urethral infection, vaginal discharge and dysuria, PID, non-painful ulcer, painful swollen lymph nodes, possible infertility, ectopic pregnancy, and perihepatitis

newborn conjunctivitis, atypical conjunctivits, can lead to blindness

azithromycin or doxycyline 

obligate intracellular parasite, detectable by serology

sinusitis → pharyngitis → bronchitis → pneumonia

persistant cough with low fever

erythromycin + tetracycline, azithromycin

obligate intracellular parasite, detectable by serology

"Parrot Fever" - headache, high fever, chills, malaise, myalgia, non-productive cough, NVD, encephalitis

tetracycline 

pleomorphic G^- coccobacilli, spore-forming, obligate intracellular pathogen, detectable by serology (MOC)

Acute Q Fever: fever/chills, headache, malaise, NVD, abd pain, hepatitis; pneumonia, cough, chest pain

doxycyline for severe cases

transmitted through aerosols of feces or placental excretions (barnyard animals)

potential bioterrorism agent - cases must be reported

vaccine available in Australia only

obligate intracellular pathogens, morulae with Giemsa or Wright stanes

Fever, headache, chills, muscle ache, NVD

detectable by PCR

Erlichia - deer, dogs, monocytic ehrlichiosis, late onset rash in 30-40 % of cases

Anaplasma - small rodents, deer, sheep, Ixodes tick, granulocytic ehrlichiosis, confusion, <10% develop rash

doxycyline

obligate intracellular pathogen (requires NAD⁺ & CoA), Gram stains poorly weakly G^-, visualized with Giemsa, detectable by serology and Weil-Felix reaction (cross reaction with Proteus), type-specific 1:64 antibody titer MOC

Rocky Mountain Spotted Fever - high fever, severe headache, NVD → rash (outward to inward, face not spared) → widespread vasculitis → organ failure

doxycycline (PRF D), chloramphenicol if pregnant (PRF C), supportive care for vascular collapse

transmitted by ticks

obligate intracellular pathogen, Gram stains poorly, visualized with Giemsa, detectable by serology (MOC)

high fever, severe headache, myalgia → rash on trunk and limbs (face usually spared) → pneumonia; can recur (Brill-Zinsser Disease)

doxycycline

transmitted by louse, persons with poor hygiene in close quarters are high risk

Rickettsialpox

transmitted by house mouse mite, eschar

obligate intracellular pathogen, Gram stains poorly, visualized with Giemsa, detected by serology (MOC)

flea bite followed by high fever, severe headache, myalgia, chills, nausea and rash

doxycycline

reservoirs include rats, cats, opossums, raccoons, and skunks

50-100 case/year in USA, higher rate of occurrence in Texas

obligate intracellular pathogen, Gram stains poorly, visualized with Giemsa, eschar

causes scrub typhus - headache, fever, NVD

doxycyline

transmitted by mite, mainly in Korea and Japan, 30% mortality rate

"Eastern Indian Ocean"

G^- pleomorphic coccobacilli, grows on Regan-Lowe Medium

Whooping Cough

macrolides (azithromycin, clarithromycin) 

prophylaxis: Zpac or vaccine 

pertactin

filamentous hemagglutinin

tracheal cytotoxin

G^- pleomorphic coccobacilli, facultative intracellular organism, urease and H₂S positive, readily isolate but BSL3 organism

undulating fever, can lead to hepatitis, splenomegaly, osteomylitis

doxycycline + gentamycin or rifampin

transmitted by direct contact with farm animals or ingestion of goat cheese

G^- pleomorphic coccobacilli, requires cysteine for growth, allow 2-4 days for growth

ulcerating papule at site of inoculation, in lungs, or in regional lymph nodes

aminoglycosides (eg. gentamicin)

transmitted in rabbits and ticks, can be aerosolized

ETEC

EAEC

EPEC

EIEC

EHEC

ETEC - adheres to jejunum and causes watery diarrhea "traveler's diarrhea"

EAEC - enetroaggressive, chronic diarrhea

EPEC - enteropathogenic, infantile diarrhea

EIEC - enteroinvasive, shigella-like plasmid-mediated invasion 

EHEC - enterohemorrhagic O157:H7

What are the properties of MacConkey agar?

What does a positive oxidase test mean?

selective for G^-, differential for fermentation

aerobe or facultative aerobe 

Fusobacterium, Clostridium, Bacteroides, Actinomyces

Anarobes Frankly Can't Breathe Air

Nocardia, Pseudomonas, Mycobacterium tuberculosis

Nagging Pests Must Breathe

• Ulceroglandular skin ulcer at the site where the bacteria entered the body accompanied by swelling of regional lymph glands, usually in the axilla or groin.
• Glandular swelling of regional lymph glands without an ulcer
• Oculoglandular bacteria enter through the eye → irritation and inflammation of the eye and swelling of lymph glands in front of the ear.
• Oropharyngeal eating or drinking contaminated food or water
• → sore throat, mouth ulcers, tonsillitis, and swelling of lymph glands in the neck.
• Pneumonic breathing dusts or aerosols containing the organism → cough, chest pain, and difficulty breathing, can ccur when other forms of tularemia (e.g. ulceroglandular) are left untreated and the bacteria spread through the bloodstream to the lungs
• Typhoidal This form is characterized by any combination of the general symptoms (without the localizing symptoms of other syndromes)