Gram- bacteria

Haemophilus influenzae — infection & features

• gram neg

• Meningitis, epiglottitis, bronchitis

• capsule, pili

• treat with 3rd gen cephalosporin (ceftriaxone/cefotaxime).

Neisseria meningitidis — disease & virulence

• gram neg

• Meningitis, petechiae, septic shock

• capsule, pili, endotoxin

• treat with penicillin or ceftriaxone.

Neisseria gonorrhoeae — disease & feature

• gram neg

• Gonorrhoea, PID, arthritis;

• pili, antigenic variation;

• treat with ceftriaxone + macrolide/doxycycline.

Escherichia coli — infection & virulence

• gram neg

• UTI, diarrhea, peritonitis;

• pili, LPS, toxins (shiga/hemolysin);

• treat with cephalosporin, fluoroquinolone, or TMP-SMX.

Salmonella enterica — infection & note

• gram neg

• Gastroenteritis (fever, diarrhea);

• invades intestine;

• no antibiotics, give fluids/electrolytes.

Salmonella typhi — disease & key trait

• gram neg

• Typhoid fever (fever, abdo pain, rash);

• capsule (Vi antigen), intracellular survival;

• treat with cephalosporin or ciprofloxacin.

Vibrio cholerae — disease & toxin

• gram neg

• Cholera with watery diarrhea ("rice water stools");

• cholera toxin → fluid loss;

• treat with rehydration + macrolide/doxycycline.

Campylobacter jejuni — disease & note

• gram neg

• Bloody diarrhea, fever;

• from undercooked poultry;

• flagella, LPS;

• treat only if severe (macrolide).

Bacteroides fragilis — infection & key point

• gram neg

• Abdominal abscess/peritonitis;

• anaerobic, capsule, enzymes;

• treat with metronidazole + drainage.

Legionella pneumophila — disease & feature

• gram neg

• Legionnaires’ pneumonia;

• intracellular survival, biofilm in water systems;

• treat with azithromycin or fluoroquinolone.

Coxiella burnetii — disease & feature

• gram neg

• Q fever (fever, pneumonia, endocarditis);

• intracellular;

• self-limiting or doxycycline.