Neisseria Gonorrhoeae

• gram -
• diplococci

Neisseria Gonorrhoeae

Virulence Factors

• Pili
• outer-membrane protein
• Lipo-oligosaccharide (LOS)--like LPS
  • Lipid A + shorter saccharide chain
  • toxic to fallopian tube cells
  • target for bactericidal antibody in serum

Neisseria Gonorrhoeae

Site of Infxn

• Urethra: urethritis
• Cervix: cervicitis
• Epididymis: epididymitis--pain & infertility
• Fallopian tubes--PID

Neisseria Gonorrhoeae Pathogenesis

• extracellular pathogen
• infects surfaces lined w/CECs:
  • endocervix, urethra, anogenital, oropharyngeal, conjunctiva
• introduced via sexual intercourse

Neisseria Gonorrhoeae Pathogenesis (2)

• attachment via pili & opa proteins
• IgA & terminal complements (C6-C9)
• IgA1 proteases promotes mucosal colonization
• serum toxicity causes rare invasion of bacteria in blood stream

Gonorrhea Rx (1)

• BETA LACTAMASE-RESISTANT CEPHALSPORIN
  • CEFIXIME OR CEFTRIAXONE
• Problems: strains carry plasmid encodes Beta lactamase
  • resistant strains can cause locally invasive dz (PID)

Gonorrhea Rx (2)

• pts often also infected w/chlamydia
• CEFTRIAXONE+AZITHROMYCIN or DOXYCYC
  • intolerance use spectinomycin

Neisseria Meningitidis

• gram -
• diplococcus

Neisseria Meningitidis

Microbiology

• capsule dictates 13 serotypes
  • A,B,C,W135,X,Y
• antiphagocytic, antipolysaccharide antibodies are protective
• outermembrane proteins
  • OPA proteins=adhesion
• pili=mucosal attachment

Neisseria Meningitidis Serogroup A

Africa & Asia

Neisseria meningitidis Serotype B/C

occasional epidemics

Neisseria meningitidis Serogroup Y

young adults in US

Neisseria meningitidis Serogroup W135

Pneumonia

Neisseria Meningitidis

Pathogenesis

• obligate human pathogen
• P2P
• adherence via pili
• invasion into blood--capsule
• avoid serum killing--capsule
• trigger inflammatory cascade--LOS

Meningococcemia: Clinical Presentation

• penetrate BBB
• duration of sx: <12 hrs
  • petechiae/purpura, fever
• blood endotoxin, cytokines
• complications
  • waterhouse-friderichsen syndrome

Meningococcemia: Clinical Presentation

• Duration of sx: 1-2 days
  • HA, stiff neck, confusion, fever, N/V

Menigoccal RX

• IV antibiotics: ceftriaxone or PCN
• steroids: dexamethasone starting 30 min before or at least concurrent with antibiotics

Menigoccal Control & Prevention

• rifampin or ciprofloxacin

E. COLI

• gram - rod
• Lactose fermenter
• easy to grow

E.COLI

(microbiology)

• facultative anaerobe
• enterobacteriaceae w/human strains
  • commensal bowel flora
  • intestinal pathogen
  • extraintestinal pathogen

E.COLI sites of infxn

• acute cystitis, pyelonephritis
• GI--diarrhea
• intra-abdominal abscess
• bloodstream
• Lung
• CNS--neonatal meningitis

Enterotoxigenic E. Coli

Major cause of traveler's diarrhea

Shiga toxin-producing E. COLI

• serotype O157:H7
• diarrhea may be bloody
• if hemolytic-uremic syndrome suspected--NO ANTIBIOTICS!!

Community acquired uncomplicated UTI

• women @ higher risk--pregnancy
• E.Coli
• staphylococcus saprophyticus

Community acquired complicated UTI

• obstruction in elderly men>>women
  • E.Coli, Proteus

Nosocomial UTI (uncomplicated or complicated)

• urinary catheterization: women>>men
  • pseudomonas
  • staphylococcus epidermidis

UTI RX

• uncomplicated UTI (only bladder):
  • TMP-SMX, Ampicillin, Fluoroquinolones
• Complicated UTI (involves kidney) C&S data

Pseudomonas

• gram - bacillus
• motile
• aerobic
• Lactose NON-fermenter

P.aeruginosa virulence factors

(motile mode)

• flagella--motility
• pili--adherence to ET cells
• Lipopolysaccharide--endotoxin
• secreted proteins
  • extoxin A
  • exoenzyme S
  • elastase
  • phospholipase C

P.aeruginosa Clinical

• inhabits moist environments (soil, water, plants & animals)
• Risk factors: neutropenia, diabetes, skin burns, cystic fibrosis, & AIDS
• Nosocomial pathogen found in hospital sinks, ice machines, soap

P.aeruginosa Infxns in normal hosts

• external otitis
• folliculitis
• hot-foot syndrome

Puncture wound osteomyelitis

• infxn of small bones of foot
• follows puncture wound 1 to 4 wks later
• due to P.aeruginosa
• linked w/stepping on nail--wearing old shoes

Ecthyma Gangrenosum

• skin lesion w/hemorrhage, necrosis, surrounding erythema
• otitis externa in pts w/DM

Nosocomial Pneumonia

• acquisition: ventilator equipment, neutropenia

• pathology: blood vessel involvement, little neutrophil response

Pneumonia in CF

• nonmucoid bacteria
• loss of flagella
• production of alginate
• loss of LPS O antigen-> serum sensitivity
• minimal invasion--no bacteremia

Pseudomonas RX

• resistant to most antibiotics
  • Cefepime/ceftazidime, piperacillin or impenem + gentamicin/tobramycin
• Cipro for less serious infxns