P. aeruginosa

• Gram negative bacilli

• Aerobic non-fermenting

• Chromatid size 5.7 Mb

• Found in soil, vegetation, water

P. aeruginosa and Nosocomial Infections

• Found in hospital environment in moist reservoirs: food, cut flowers, sinks, toilets, floor mops, medical equipment, disinfectant solutions.

• Common problem in immunocompromised patients, burn victims, resident catheters, cystic fibrosis

• Resistant to antibiotics

P. Aruginosa Virulence Factors I• Adhesins

• Alginate Production

• Endotoxin

• Neuraminidase

• Exotoxin A

• Exoenzyme S

P. Aruginosa Virulence Factors II

• Elastolytic Activity - LasA, LasB

• Phospholipase C

• Pyocyanin, Pyochelin

• Antibiotic Resistance

Mycobacteria

• Non-motile, aerobic gram positive bacilli• Acid-fast• Slow growth• Resistant to detergents• Immunostimulatory• 74 different species, a third associated

with human disease e.g M. tuberculosis, M. leprae

Mycobacteria

Bacteria reach lungs;enter macrophages

Bacteria reproduce in macrophages

Lesion begins to form (caseous necrosis)

Bacteria cease to grow; lesion calcifies

Reactivation

Lesionliquifies

Bacteriacoughedup insputum

Spread toblood, organs

Death

Granulom a

DeadPhagocytes

M. Tuberculosis Diagnosis

• Mantoux test – PPD

• Positive test – Redness and swelling (erythema)

Hardening (induration)

• Disadvantages – BCG Vaccination Slow development Anergy

M. Leprae

• Disease – Leprosy (Hansen’s disease): tuberculoid and lepromatous form.

• Virulence factors – unknown

• Transmission – Lepromatous leprosy: Highly infectiousTuberculoid leprosy:Low

N. gonorrhoea

Aerobic, gram negative cocci. Horizontal and vertical transmission Health Problem:

High rate of asymptomatics Antigenically variable

N. gonorrhoeae

N. gonorrhoeae

N. gonorrhoeae

Oropharyngeal infection

Anal or genitalInfection

Cervical infection(symptomatic or asymptomatic)

Surface colonizationof infant at birth

Pharyngitis

Local irritation,discharge

Asymptomatic(especially women)

Ascending infection ofuterine cavity, fallopiantubes (pelvic inflammatorydisease, infertility, ectopicpregnancy)

Eye infectionBlindness

Conjunctivitis

Systemicspread 1%(arthritis,endocarditismeningitis)

N. gonorrhoea Virulence Factors

• Capsule

• Pilus (PilE, PileS antigenic variation)

• Opa (Slipped strand mispairing)

• LOS

• Iron binding proteins: Tbp1,2,Lbp

• Protease

Stages in interaction of N. gonorrhoeae with cultured mammalian cells

Stages in interaction of N. gonorrhoeae with cultured mammalian cells

Phase Variation II: Slipped Strand Mispairing