Gram Negative Bacteria

Front 1

E. coli

Back 1

Gram Neg
Family: Enterobacteriaceae
Ferments lactose. Humans major reservoir (except EHEC)
Virulence Factors:
1.) Specific Pili (fimbrial): UTI, most common cause.
2.) K capsular: neonatal meningitis, gram neg scepticaemia.
3.) Wound infections w. bacteroides fragilis, group D strep.

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Proteus/Providencia/Morganella

Back 2

Gram Neg
Family: Enterobacteriaceae
Virulence Factors:
1.) Urease: splits urea and ↑pH, promotes struvite stone formation. Stones obstruct flow, act as nidus for persistent infxn.
Notes: motile; swarm solid media.

Front 3

Klebsiella (K. pneumoniae)

Back 3

Gram Neg
Family: Enterobacteriaceae
Virulence Factors:
1.) capsule: high level of antibiotic resistance.
2.) Community-acquired lobar pneumonia, in alcoholic men 40+ yrs old.
3.) Nosocomial infxns of lower resp. tract, urinary tract, surgical wounds.
Notes: major opportunist

Front 4

Enterobacter

Back 4

Gram Neg Rod
Family: Enterobacteriaceae
Virulence: Opportunist;, burn, wound, resp., urinary (UTI) infxns, bacteraemia.

Front 5

Citrobacter

Back 5

Gram Neg
Family: Enterobacteriaceae
Virulence:
1.) Nosocomial infxn in pts with compromised immune sys
2.) Meningitis, brain abscess in neonates.

Front 6

Serratia

Back 6

Gram Neg
Family: Enterobacteriaceae
Virulence: Nocosomial infxns, UTI, wound, pneumonia, septicaemias.
Notes: produces red pigment in culture.

Front 7

Yersinia

Back 7

Gram Neg
Family: Enterobacteriaceae
Virulence:
Y. pestis: plague
Y. enterocolitica: severe diarrhoea, local abscess.
Y. pseudotuberculosis: severe enterocolitis.

Front 8

Gastroenteritis

Back 8

Sxs: vomiting, nausea, diarrhoea, abdominal discomfort

Front 9

Diarrhoea

Back 9

Disease of the small intestines; ↑'d fluid/electrolyte loss, frequent and/or fluid stool.

Front 10

Dysentery

Back 10

Inflammatory disease of large intestines. Frequent passage of small volume stools with blood, mucus, pus, severe abdominal cramps, tenesmus.

Front 11

Salmonella

Back 11

Gram Neg
Class: enterobactericiaea
Notes; only salmonella enterica (6 subspecies, 5 serogroups) infect humans. Do not ferment lactose.
Virulence factor (enteritis): 2 salmonella pathogenicity islands for Type III secretion systems. Vi antigen. Stomach pH activates transcription of factors.
1.) PhoP/PhoQ: Typhoid fever
2.) gastroenteritis
Dx: black colonies on HEA.

Front 12

Enteric/Tyhoid Fever

Back 12

Agent: Salmonella Typhi; ingestion of food/water contaminated with human faeces/urine.
Path: Crosses intestinal epithelial via M cells, invades macs, disseminates via lymphatics.
Sxs: prolonged, step-wise ↑g fever, diarrhoea, constipation, rose spots (rash), hepatosplenomegaly, GI preforration/haemorrhage(late).
Notes: Immunity requires cell and humoral responses.

Front 13

PhoP/PhoQ

Back 13

Important virulence factor of S. Typhoid; two regulatory systems that senses the intracellular environment and induces transcription of genes necessary for survival inside macs.

Front 14

Gastroenteritis

Back 14

Agent: S. Typhimurium, S. Enteritidis.
Path: Ingestion of contaminated foodstuffs (chicken, eggs). Invades both M cells and macs (unlike typhoid). Induces electrolyte fluxes, cytoskeletal rearrangements, mem. rffling, bacterial internalisation, syn. of IL-8, prostaglandin-induced inflammation.
Virulence Factors: SPI encoding type III secretion system.
Sxs: loose, non-bloody stools of moderate volume. Many leukocytes in stool. Usu. actue, self-limiting infxn.

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Type III secretion system

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Key virulence factor of salmonellas causing gastroenteritis, encoded by Salmonella Pathogenicity Islands (SPI). Mediates translocation of secreted effector proteins into target epithelial cells necessary for invastion and sxs.

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Bacteraemia

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Most common in infants, elderly, immunosuppressed, sickle-cell anaemia.
Common Agents: S. choleraesuis, S. Dublin.

Front 17

Salmonella osteomyelitis

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an infection rarely seen in pts. without sickling disorders. Asplenic state of these pts. give ↑'d susceptibility to infxn.

Front 18

Shigella

Back 18

Gram negative rods
Class: enterobacteriaceae
Does not ferment lactose or produce H2S. Nonmotile. 4 species. Humans are only reservoir, not part of normal flora.
Virulence Factors: Shigella PAI on virulence plasmid (codes for Type III secretion), shiga toxin (s. dysenteriae type I), stomach acid resistence (small # cause disease).
Diseases: shigellosis
Dx: green, transparant colonies on HEA.

Front 19

S. sonnei

Back 19

Late lactose fermentor (unlike most other shigellas that don't ferment). Most common isolate in developed countries.
Transmission: P2P dir. contact, water sports, faecal contamination.
Sxs: watery diarrhoea

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S. flexneri

Back 20

Most common shigella in developing countries.
Transmission: food/water faecal contamination.

Front 21

S. dysenteriae Type I

Back 21

aka Shigella bacillus; cause of Classic Bacillary Dysentery, a severe dysentery in distal colon. Virulence: Shiga toxin

Front 22

S. boydii

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Shigella seen only in India

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Shigellosis

Back 23

Sxs: watery diarrhoea or dysentery (cytokine-mediated inflamm. of distal colon). Onset 12-48 hrs post-ingestion. Most infxns self-limiting.
Tx: Rehydration. No vaccine.

Front 24

Actin Propulsion System

Back 24

Actin tail "pushes" shigella into adjacent enterocyte. This occurs after shigella gets through M cell, then into mac, stimulates mac apoptosis, and gets into enterocyte.

Front 25

Shiga Toxin

Back 25

Produced by S. dystenteriae type I. A subunit acts on 60S, stops protein syn. 5 identical B subunits fxn in binding to host cell.

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Enterotoxigenic E. Coli (ETEC)

Back 26

Disease: Traveller's Diarrhoea.
Site: Small intestines.
Transmission: faecal-oral.
Sxs: rapid onset watery diarrhoea 1-5 days.
Virulence: Colonising Factor Antigens (CFA), enterotoxins (cholera-like).

Front 27

Enteroinvasive E. Coli (EIEC)

Back 27

Disease: similar but less severe than shigellosis
Site: colonic mucosa.
Sxs: watery diarrhoea followed by dysentery.
Virulence: large plasmid.

Front 28

Enteropathogenic E. Coli (EPEC)

Back 28

Disease: infant diarrhoea in developing countries.
Virulence: pilus-mediated (bundle-forming pilus); attaches to and effaces brush border.

Front 29

Enteroaggregative E. Coli (EAEC)

Back 29

Disease: watery diarrhoea in developing countries, esp. young children.
Virulence: interferes with transport properties of target cells.

Front 30

Enterohaemorrhagic E. Coli (EHEC)

Back 30

Most common strain in developed countries.
Disease: uncomplicated diarrhoea, Haemorrhagic colitis, HUS. Common in warm months.
Transmission: bovine origin; undercooked hamburgers.
Sxs: bloody diarrhoea, abdominal pain.
Virulence: Bundle-forming pili (A/E lesion), SLT-II (Shigella-like toxin).
Dx: sorbital negative

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Haemolytic Uraemic Syndrome (HUS)

Back 31

Sxs: haemolytic anaemia, throbocytopaenia, acute renal failure.
Pop.: young children, eldery.
Agent: EHEC; due to SLT-II

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Pyelonephritis

Back 32

Agent: small # of O-serotype E. coli, ones that produce haemolysin and siderophore (aerobactin). 80% produce P fimbriae, a marker for pyelonephritic strains.

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Meningitis

Back 33

Agent: Most common E. coli. Second group B strep (S. agalactiae), 3rd Listeria, Neisseria meningitidis.
Virulence: 75% have K1 surface polysaccharide Ag for bloodstream survival.

Front 34

Campylobacter

Back 34

Family: campylobactereceae
slender, curved/spiral gram negative rods, motile, microaerophilic, slow-growing.
Reservoir: animals (zoonosis)
Diseases: C. jejuni enteritis.
Dx: grows on Campy Blood Agar. (Highly selective)

Front 35

C. jejuni

Back 35

Disease: common cause of bacterial gastroenteritis in developed countries.
Epidemiology: peaks in summer/early fall. Infants highest infxn.
Transmission: poultry
Sxs: fever, bloody diarrhoea, abdominal pain, >10 BM/day, ulceration.

Front 36

C. fetus

Back 36

Disease: extra-intestinal diseases; diarrhoeal illness similar to C. jejuni, replasing systemic diseases.

Front 37

Helicobacter pylori

Back 37

Spiral gram neg rod; highly motile.
Colonises human stomach
Diseases: peptic ulcer disease, gastric malignancy.
Reservoir: unknown
Virulence factors: urease (neutralises gastric pH), flagella, adhesins, VacA (vacuolating cytotoxin), cag PAI (inflamm.)
Tx: antimicrobial + proton pump inhibitor

Front 38

Vibrio cholerae

Back 38

curved, motile, gram neg rod
Disease: cholera (usu. serogroup-O1)
Reservoir/habitat: salt water.
Virulence: Cholera Toxin (ADPribosyltransferase A/B toxin), mucinase (helps penetrate mucous layer of S.I.)
Dx: yellow colonies on TCBS (thiosulfate citrate bile sucrose)

Front 39

Cholera

Back 39

Agent: v. cholerae
Sx: rice water stool; hypovolaemic shock/death
Tx: rehydration.
Vaccine: killed whole-cell, ctxB subunit toxoid combo; or live attenuated

Front 40

V. parahaemolyticus

Back 40

Marine organism found in esturaries
Disease: self-limiting diarrhoea, mild cholera-like ilness.
Transmission: contaminated seafood (esp. shellfish).
Dx: blue-green colonies on TCBS (thiosulfate citrate bile sucrose).

Front 41

V. vulnificus

Back 41

Disease: rapid progressive wound infxn, fulminant bacteraemia.
Transmission: exposure to contaminated seawater, consumption of raw oysters.

Front 42

Aeromonas

Back 42

Family: enterobacteria
name-recognition only; gram neg, implicated in diarrhoeal/extraintestinal diseases

Front 43

Plesiomonas

Back 43

Family: enterobacteria
name-recognition only; gram neg, implicated in diarrhoeal/extraintestinal diseases

Front 44

Neisseria

Back 44

Gram negative dipploccoci; non motile.
Oxygen: obligate aerobes, facultative if KNO2 present.
Host: only humans
Fastidious, grows only on CBA.

Front 45

N. Gonorrhoeae

Back 45

Grows in glucose, not maltose. Oxidase positive
Disease: gonorrhoea, PID, DGI
Virulence: pilli, OMP, LOS, penicillin resistence common in Asia/Africa, Tetracyclin resistence found.
Vaccine: none, due to antigenic/phase variation of pili/OMPs.

Front 46

Gonorrhoea

Back 46

2nd most common STD.
Incubation: 2-7d
Sxs: male: acute urethritis
Sxs (female): cervicitis, urethritis, vaginal discharge, abdominal pain, dysuria, progression to PID (sterility, ectopic pregnancy)
Male Dx: GNC in urethral exudate with PMNs
Female Dx: culture isolation of oxidase-pos, GNC from cervix/anal canal
Tx: ceftriaxone+tetracycline

Front 47

Gonococcal arthritis-dermatitis syndrome

Back 47

Manifestation of disseminated gonoccocal infxn (DGI).
Sxs: tenosynovitis (joint inflamm.), suppurative arthritis (jnt. infxn.)

Front 48

Outer Membrane Protein

Back 48

Chief virulence factor in N. gonorrhoeae; fxn in adherence, controlled by opa genes. Phase variation switches gene on/off with frameshifts, antigenic variation changes AA composition.
OMP-I: surivial inside phagocytes
OMP-II: homologous recomb. involving slipped-strand mispairing.

Front 49

Lipooligosaccharide (LOS)

Back 49

Virulence factor of N. gonorrhoeae, containing sialic acid (found on RBCs) that may mask it the bacteria from Abs. Triggers TNF-α, scars oviducts. Required for binding to sperm.

Front 50

Transferrin/Lactoferrin Binding Proteins

Back 50

N. gonorrhoea uses to steal iron from transferrin/lactoferrin.

Front 51

Neisseria Meningitidis

Back 51

Gram neg dipplococci
Diseases: nasopharyngeal infxn, meningococcaemia, meningitis.
Virulence: capsule (grp A/C immunogenic, grp B not.), pili, endotoxin, OMP, IgA protease.
Pathogenic serotypes: B, C, Y
Tx: rifampin, ciprofloxacin

Front 52

Moraxella (Branhamella catarrhalis)

Back 52

Gram neg dipplococci; confused for Neisseria
Diseaese: otitis media, lower resp. tract infxns.

Front 53

Meningococcal Disease

Back 53

Stages:
1.) nasopharyngeal infxn - usu. asymptomatic.
2.) colonisation of mucous mem. - pili
3.) Haematogenous dissemination - metastatic lesions; febrile to systemic.

Sxs: petechiae to ecchymoses; meningococcaemia/meningitis possible.

Dx: CSF gram stain; culture on choc. agar is definitive.

Front 54

Pseudomonas Aeruginosa

Back 54

Gram neg rod; motile, oxidase+, ferment-. Anaerobic if nitrate available. Non fastidious.
Diseases: bacteraemia, pneumonia (CF), UTIs, ecthyma gangrenosum, wound sepsis, endocarditis, meningitis, otitis externa, keratitis, corneal ulcer, blood/jnt infxns (IV drug users).
Virulence: cell-associated and extracellular.

Front 55

ecthyma gangrenosum

Back 55

Skin manifestation of Ps. aeruginosa infxn, esp. in bacteraemic pts. Haemorrhagic lesion due to destruction of elastin by elastase. Can occur w. other gram- bac.

Front 56

Nonbacteraemic Pneumonia aka 1° Pneumonia

Back 56

Acute Ps. aeruginosa infxn; due to aspiration of URT secretions. Associated w. ventilator use.

Front 57

Bacteraemic Pneumonia

Back 57

Fulminant ps. aeruginosa infxn associated w. neutropaenia (post-chemotherapy).

Front 58

Cell-associated Virulence Factors of Ps. Aeruginosa

Back 58

1.) Pili
2.) Mucoid exopolysaccharide (MEP/alginate). Helps colonise in CF, also allows biofilms.
3.) LPS - protects from complement, Abs.
4.) flagella - motility, attachment

Front 59

Extracellular Virulence factors of Ps. Aeruginosa

Back 59

1.) proteases - elastases, alkaline protease.
2.) exotoxin A: ADP ribosyltransferase, ~diphtheria toxin.
3.) Type III cytotoxins
4.) pyochelin, pyoverdin - scavenger iron siderophores
5.) pyocyanin - blue-green; induces production of toxic O2 free radicals to kill resp. epithelial cells.

Front 60

Burkholderia cepacia

Back 60

GNB, ferment-, formerly pseudomonas. Opportunist.
Disease: nosocomial resp. infxns in pts. w. CF or chronic granulomatus disease. UTIs in catheterised pts. Septicaemia.

Front 61

Bacteroides fragilis

Back 61

GNB anerobic. Main species in wound infxns.
Virulence: pili, capsule (abscess formation), succinic acid (inhibits PMNs, superoxide production).
Tx: metronidazole.

Front 62

Legionella pneumophilia

Back 62

Slender, pleomorphic obligate aerobic intracellular GNR. Stains v. poorly. Fastidious, slow growing on BCYE. Flagellated, motile.
Habitat: aquatic protozoan parasite or biofilms; must be aerosolised for transmission. No P2P, humans are dead end hosts. Life cycle has transmission, replication phase.
Possible manifestations: asymptomatic, Legionnaire's Disease, Pontiac Fever.
Dx: culture in BCYE, urinary Ag testing, many PMNs but no bacteria seen.

Front 63

Legionnaire's Disease

Back 63

Agent: L. pneumophilia
Time: summer to fall.
Pts: >55, smokers, chronic pulm. disease.
Sxs: myalgia, heachache, rapidly rising fever, non-productive cough w. 2-10d onset (atypical pneumonia). Can end in shock, resp. failure.
Mortality: 15%
Tx: Macrolides, eg. azithromycin.

Front 64

Legionella Virulence Factors

Back 64

1.) Invasion proteins: entry & survival inside mac, no lysosomal fusion. (mip, dot/icm)
2.) Iron extraction from host.
3.) (-)n of oxidative killing by PMNs.
4.) Pore-forming toxin.

Front 65

Pontiac Fever

Back 65

Agent: L. pneumophilia
Non-pneumonic manifestation of Legionella. Nonfatal, self-limiting.
Sxs: rapid onset of fever, chills, headache, sever mm aches. Flu-like. Always epidemic form.

Front 66

Mycoplasma

Back 66

Smallest known free-living bacteria; require sterols for growth. Extracellular. No cell wall, triple layer mem. Fried egg appearance. Will not gram stain.

Front 67

M. pneumoniae

Back 67

Reservoir: humans
Transmission: aerosolised droplets (cf. Legionella).
Diseases: walking pneumonia: acute resp. disease; tracheobronchitis, atypical pneumonia (most common cause, esp. school-aged chilren, teenagers).
Virulence: P1 (attachment to resp. epithelium in between cilia), H2O2 (tissue toxin against ciliary fxn; loss of escalator)
Dx: serologic tests; cold haemagglutinin test. PCR. Many monos, but no bacteria seen (can't gram stain)
Tx: tetracyclines, macrolides.

Front 68

M. hominis, U. urealyticum

Back 68

Energy: Mycoplasma (glucose), Ureaplasma (urea).
Disesaes: BV, PID, resp. infxns (newborns), NGU.

Front 69

Treponema spp

Back 69

High motile, helically coiled spirochetes. Axial fibrils wind around cylinder. Does not stain, visualised by Dark Field Microscopy or immunoflurescence. Cannot be cultured

Front 70

Syphilis (general)

Back 70

Agent: T. pallidum
Reservoir: humans
Transmission: sexual contact w. infectious lesions (chancre, rash, condyloma lata, mucous patches).
Path: slow evolving, chronic systemic infxn in stages. Systemic infxn occurs long before 1° lesion appears.
Dx: Darkfield detection of spirochetes, serology, non-treponemal serology tests, Wasserman test (complement-fixation).
Tx: penicillin G (no vaccine), watch for Jarisch-Herxheimer rxn.

Front 71

1° syphilis

Back 71

Onset: 3-4wks after contact
Sx: Indolent, hard, indurated chancre at site of inoculation filled w. treponema. Regional lymphadenopathy. Heals spontaneously.

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2° syphillis (disseminated syphillis)

Back 72

Onset: 2-8 wks after healing of chancre.
Sxs: generalised indolent, non-pruritic mucocutaneous rash (condyloma lata) or highly infectious erhthematus plaques (warm moist areas)

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Latent Stage (syphilis)

Back 73

Time: yrs to life.
Spirochetes sparse, but may spread to foetus or seed blood stream intermittently.
Treponemal/nontreponemal tests all positive.

Front 74

3° syphillis (late syphilis)

Back 74

Onset: yrs after initial infxn.
Sx: slowly progressive inflammatory disease. Neurosyphilis, cardiovascular syph., gummas (liver granuloma).

Front 75

Early Syphilis

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Stages of syphilis that occur within first year of acquisition (1°, 2°, early latent).

Front 76

Congenital Syphilis

Back 76

T. pallidum readily crosses the placenta.

Front 77

Specific (Treponemal) Serologic Tests

Back 77

FTA-ABS and MHA-TP. Detect specific treponemal Abs. Remain positive even after successful Tx, unlike non-treponemal tests.

Front 78

Leptospira interrogans

Back 78

Zoonotic organism, looks like question mark.
Disease: Leptospirosis, Weil's Disease.
Ts: rat urine-contaminated water.
Sx: mild, flu-like. Rare severe 2nd phase (Weil's Disese) has hepatic/renal impairment, jaundice, prostration, circ. collapse, meningitis-like Sxs.

Front 79

Borrelia burgdorferi

Back 79

Weakly staining gram- spirochete; difficult to culture.
Disease: Lyme Disease
Reservoir: mouse
Vector: Ixodes tick
Vaccine: no longer available.

Front 80

Lyme Disease

Back 80

Agent: B. burgdorferi
Stage 1: localised infxn, erythema migrans (bull's eye).
Stage 2: disseminated infxn; 2° skin infxns, fever, neurologic, cardiac, musculoskeletal sxs.
Stage 3: persistent infxn: arthritis.
Dx: exposure to endemic area, erythema migrans, serologic ELISA.
Tx: doxycycline

Front 81

Relapsing fever

Back 81

Agents: B. recurrentis (louse-borne), other Borellia spp. (tick-borne)
Path: organism undergoes multiple cyclic antigenic variations
Sxs: cyclic pattern of fever followed by sweating weakness.

Front 82

Bartonella

Back 82

GNB; fastidious, slow-growing.
Reservoir: B. henselae (cats), B. quintana (humans, via lice).
Diseases: cat scratch disease, bacillary angiomatosis

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Cat Scratch Disease (CSD)

Back 83

Agent: B. henselae
Vector: loveable cats
Sx: regional lymphadenopathy. Typically benign infxn in children.

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Bacillary Angiomatosis (BA)

Back 84

Agent: B. quintana, B. henselae
Pts: HIV
Sx: unique vascular lesions of skin.

Front 85

Bordetella pertussis

Back 85

Small aerobic GNR; fastidious.
Adults reservoir for infants, P2P via aersol.
Oddities: strong tissue tropism; only attaches to ciliated cells of trachea, bronchi.
Disease: Whooping cough
Virulence: Pertussis toxin, AC toxin, dermonecrotic toxin, tracheal toxin, adhesins.

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Pertussis (Whooping Cough)

Back 86

Agent: B. pertussis
path: toxin-mediated paralysis of cilia, causing inflammation of resp. tract. Escalator lost, pneumonia likely.
Onset: 7-10d
Stages: catarrhal, paroxysmal cough, convalescent.
Complications: 2° bacterial pneumonia, seizures, encephalopathy.
Dx: elevated WBC w. lymphocytosis, PCR, culture (difficult), DFA/
Tx: 1°ly supportive. Erythromycin, vaccine.

Front 87

Pertussis Toxin

Back 87

Classic A/B toxin targets immune effector cells, preventing bacterial clearance. Causes lymphocytosis (blocked migration to lymph nodes)

Front 88

Adenylate Cyclase Toxin

Back 88

Virulence Factor of B. pertussis. Targets early immune defences (neutrophils). Lyses RBCs. Confuses neutrophils, blocking chemotaxis, phagocytosis, superoxide generation, and microbial killing.

Front 89

Dermonecrotic Toxin

Back 89

Virulence Factor of B. pertussis.
Effect: blue-black lesions, death at high doses. Modifies ρ-protein. Exact role uncertain, possibly (-)s phagocytosis.

Front 90

Tracheal Cytotoxin

Back 90

B. pertussis toxin, derived from peptidoglycan.
Effect: induces toxic levels of IL-1, analogous to endotoxin. Causes ciliastasis, destruction.

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B. Pertussis adhesins

Back 91

1.) FHA: aggregation of RBCs, rod-like sxr.
2.) fimbriae/pili: expression variable & varied.
3.) pertactin: attachment to human cells via RGD tripeptide (consensus seq. of integrin family)
4.) BrkA: protects bacteria from complement. Has 2 RGD sequences.

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Catarrhal Stage of Pertussis

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First stage.
Onset: insidious
Sx: coryza (runny nose), sneezing, low-grade fever, mild occasional cough. Cold-like.

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Paroxysmal Cough Stage of Pertussis

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2nd stage, 1-2wks after catarrhal stage.
Sx: bursts of numerous, rapid coughs, ended by characteristic high-pitched whoop. Attacks more at night. Lasts 1-6 wks.

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Convalescent Stage of Pertussis

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3rd stage; recovery graduatl. Cough disappears over 2-3 wk period. Paroxysms often recur.

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Pertussis Vaccine

Back 95

Whole-cell: not sued in US anymore. Very effacacious, but expensive, risk of acute encephlopathy.
Acellular: purified, inactivated components. Primary given 2, 4, 6 months. Booster at 18 months and before school, then age 10.

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Haemophilis Influenzae

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Mostly aerobic GN coccobacillus. Capsular type b (Hib) virulent. Requires X, V factors (chocolate agar).
Reservoir: man.
Virulence Factors: PRP capsule (unencapsulated forms normal nasopharyngeal flora)
Disease: meningitis in children <5 yrs, epiglottitis, osteomyelitis, pericarditis. Nontypable: otitis media, acute bronchitis.
Dx: gram stain, culture, latex agglutination, CIE.
Tx: chloramphenicol or 3rd gen. ceph. Prophylaxis w. rifampin.

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Hib vaccine

Back 97

Pure Polysaccharide Vaccine (HbPV): not effective in children <18 months (when needed the most), due to T-independent nature.
Polysaccharide-protein conjugate vaccine: T-dependent vaccine works in young children.

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Yersinia pestis

Back 98

Small, gram- coccobacillus w. bipolar staining. Enterobacteriaceae. Intracellular.
Dieases: bubonic plague, pneumonic plague.
Virulence: endotoxin, Pla, F1 antigen, V antigen, YadA, lcr, yop. Factors turned on only at 37ºC, low Ca2+. Allows survival in macs, not PMNs.
Vector: fleas.
Tm: sylvatic via nonurban animals, urban via rats.
Notes: progression to 2º disease allows P2P spread.
Dx: Bipolar staining bacilli. Detect F1 antigen.
Tx: streptomycin.

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1º Bubonic Plague

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Most common form of plague.
Sx: sudden onset fever, painful bubo (enlarged lymph node) in groin area, bacteraemia, death by septic shock.

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1º Pneumonic Plague

Back 100

Agent: Y. pestis.
Deadliest form of plague (100% mortality w/o Tx). Death by 2-3d.
Tm: P2P via droplet.

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1º Septicaemic Plague

Back 101

Sxs: DIC, haemorrhages in skin, necrosis of small vessels, no obvious buboes. Mortality 100% w/o Tx.

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Yersinia enterocolitica

Back 102

Reservoir: cattle, pigs.
Tm: pork products.
Sx: enterocolitis. Can mimic appendicitis.
Pt.: children > adults, more in winter.
Virulence: grows at low temps (25°C)

Front 103

Yersinia pseudotuberculosis

Back 103

Zoonotic infxn that occasionally causes human disease.
Tm: contaminated food/drink
Sx: acute mesenteric lymphadenitis, disseminated infxns.

Front 104

Franciscella tularensis

Back 104

Very small faintly staining gram- coccobacillus. Nonmotile, nopiliated, fastidious. Facultative intracellular parasite in macs. Highly infectious.
Tm: rabbits, muskrats via ticks. No P2P spread. Cat. A biological weapon.
Endemic area: AR, MO, OK

Front 105

Tularaemia

Back 105

Agent: F. tularensis
Path: enters thru skin abrasions, bites. 3-5d incubation, invades RE organs, forms granulomas (ulceroglandular tularaemia).
Sx: fever, chronic ucerative skin lesion, large tender lymph nodes.
Dx: clinical+geographic.
Tx: Avoidence, CMI. Vaccine v. dangerous.

Front 106

Brucella spp.

Back 106

Small, nonmotile, nonencapsulated gram- coccobacilli. Fac. intracellular.
Area: CA, TX.
Reservoir: goats/sheep (B. melitensis), cattle (B. abortus), hogs (B. suis), dogs (B. canis).
Tm: ingestion of contaminated product or direct contact (no insect vector).

Front 107

Brucellosis

Back 107

Agent: brucella spp
Path: fac. intracellular parasite of RES, multiply in macs. Block degranulation.
Sx: malaise, chills, undulant fever (cf. borreila relapsing fever), chronic illness.
Dx: hx of exposure. Serologic test presumptive. Isolation of brucellae definitive.
Tx: avoidance, vaccine, pasteurisation.

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Chlamydia spp.

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Obligate intracellular small gram-. No peptidoglycan layer! MOMPs basis for serotyping. Unique biphasic development cycle: Elementary Body (EB) is spore-like, Reticulate Body (RB) is vegetative, intracellular. RB converts back to EB before exiting a cell.

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Chlamydophilia psittaci

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Disease: human ornithosis; zoonoitc inhalation of aerosolised bacteria from birds. Human infxns rare.
Sx: atypical pneumonia.
Dx: serologic.

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Chlamydophilia pneumoniae

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Tm: human only pathogen. P2P via resp. route.
Sx: pharyngitis to severe pneumonia.
Dx: no good tests available!

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Chlamydia trachomatis

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Obligate intracellular gram-, replicates in endosomes.
Diseases: trachoma, inclusion conjunctivitis, LGV, genital tract infxns, NGU, neonatal pneumonia/conjunctivitis.
Dx: NAAT techniques, DFA, EIA.
Tx: azithromycin

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Trachoma

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Agent: C. trachomatis, serovars A, B, Ba, C.
Chronic conjunctivitis, seen usu. in Africa.
Path: persistent ocular infxns starting in childhood, leading to blindness from mechanical scratching of cornea by disfigured eyelids.

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Inclusion Conjunctivitis

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Agent: C. trachomatis, serovars D, E, F, H, I, J, K.
Path: babies born to mothers infected with C. trachomatis may develop this conjunctivitis. Does not cause blindness.

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Lymphogranuloma venerum (LGV)

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Agent: C. trachomatis, serovars L1, L2, L3.
Range: S.A., Africa.
Sx: 1° lesion followed by lymphadenopathy, systemic sxs.

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Genital Tract Infections of C. trachomatis

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Most common bacterial STD, by serovars D, E, F, H, I, J, K (same as inclusion conjunctivitis)
Reservoir: asymptomatic pts.
Sx: unlike N. gonorrhea, less acute, more chronic complications. Mild purulent inflammation, septic arthritis (Reiter syndrome). Can lead to PID, infertility, ectopic pregnancy.

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Rickettsia rickettsii

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GNB, obligate intracellular energy parasite, lives in cytoplasm, utilises F-actin polymerisation.
Epidemiology: tick is reservoir and vector. April-Sept. Appalachian Mts. 2/3 pts. <15yo. However, older pts have more severe disease.
Disease: Rocky Mountain Spotted Fever.

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Rocky Mountain Spotted Fever

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Agent: R. rickettsii
Sx: acute fevers, headache, myalgia. Then disseminates via blood, replicates in endothelial cells. Centripetal spread of rash (palm→trunk)
Path: 1° lesion is vasculitis (rash, petechial lesions).
Dx: clinical/epidemiologic. Rising Ab titer. Indirect fluorescent Ab test (pos. 2-3 wks after onset)
Mortality: 20-25%, 3% w. Tx

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Rickettsia prowazekii

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Disease: louse-borne typhus.
Tm: no P2P, only via louse. However, humans 1° reservoir.
Sx: fever, headache, rash. Centrifugal spread (trunk→palm).
Complications: recrudescent typhus (Brill's disease), a relapse.
Notes: seen in times of misery. Epidemic disease (cf. R. typhus, endemic disease)

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Rickettsia typhi

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Diseases: endemic/murine typhus.
Tm: rat to flea to human.

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Orienta tsutsugamushi

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Disease: scrub typhus.
Notes: major cause of undiagnosed febrile illness in soliders in Vietnam.

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Coxiella burnettii

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Very hardy obligate intracellular gram-; grows in lysosomes. Extremely infectious.
Disease: Q fever
Sx: acute pneumonia, chronic endocarditis.
Tm: inhalation of particles from animals. Very hardy.
Notes: undergoes antigenic variation of LPS.

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Ehrlichia chaffeensis

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Obligate intracellular gram-, lives in vacuoles.
Disease: human monocytic erlichiosis.
Tm: tick-borne, deer reservoir
Path: Enters through break in skin (cf. RMSF), infects monocytes.
Sx: febrile, rash in 10-35%, often asymptomatic.

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Anaplasma phagocytophilum

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Obligate intracellular gram-, lives in vacuoles.
Disease: human granulocytic anaplasmosis
Tm: tick-borne, white-footed mouse reservoir
Path: Enters through break in skin (cf. RMSF), infects monocytes.
Sx: febrile, rash in 10-35%, often asymptomatic.