Gram negative Diplococci and Coccoid Rods Flashcards
What two bacteria are gram negative diplocci?
Neisseria meningococci and gonococci. Both ferment glucose, both produce IgA protease.
How can they be differentiated?
Meningo = maltose fermenter.
Which neisseria is often intracellular, within neutrophils?
Gonorrhea.
Which neisseria has a polysaccharide capsule?
Meningococci.
Which neisseria can be vaccinated against?
Meningococci.
Why can’t one of the neisseria be vaccinated against?
Pilus proteins have high level of antigenic variation.
How is N. gono transmitted?
sexually or perinatally
How is N. meningo transmitted?
Respiratory/oral secretions.
What is the disease presentation associated with N. gono?
Gonorrhea, septic arthritis, PID, Fitz-Hugh Curtis
Neonatal conjunctivitis
What is the disease presentation associated with N. meningo?
Meningococcemia and meningitis
Waterhouse-Friderichsen syndrome (adrenal hemorrhage).
What prevents N. gono disease?
Condoms decrease sexual transmission.
Erythromycin ointment prevents neonatal transmission.
What prevents N. meningo disease?
Rifampin, cipro, or ceftriaxone prophylaxis in close contacts
What is the treatment for N. gono disease?
Ceftriaxone (+ azithro or doxy for chlam coinfection)
What is the treatment for N. meningo disease?
Ceftriaxone, penicillin G.
Which bacteria are gram negative coccobaccilary organisms?
H. influenza
Bordatella
Pasteurella
Brucella
How is H. influenza transmitted?
Aerosol transmission.
What does the H. influenza b. vaccine contain?
Type B capsular polysaccharide (polyribosyribitol phosphate) conjugated to diptheria toxoid or other protein. .
when is Hib vaccine given?
Between 2 and 18 mos.
Why didn’t the Hib cure all H. influenza infections?
Most infections caused by non-typeable strains.
What special culture is H. flu grown on?
Chocolate agar, which contains factor V (NAD+) and X (hematin).
How else can H. flu be grown?
With staph aureus, which provides factor V through hemolysis of RBCs.
What disease does H. influenza cause?
haEMOPhilus. E: epiglottitis M: meningitis O: otitis media P: Pneumonia
How are mucosal H. influenza infections treated?
Amoxicillin +/- clav.
How is H. influenza meningitis treated?
Ceftriaxone, rifampin ppx for close contacts.
What is the difference between H. influenza that cause meningitis, epiglottis, and those that cause otitis media and sinusitis?
Otitis media and sinusitis ones are not encapsulated.
How is bordatella pertussis transmitted?
Respiratory route
What virulence factors does bordatella have?
Capsule, betalactamase Filamentous hemagglutin (FHA), pili rod that enables bac to bind to ciliated epithelial cells of bronchi
How does pertussis toxin work?
- Activates G proteins that increase cAMP
- inc histamine sens, insulin release, lymphs - Extracytoplasmic adenylate cyclase
- weaks neuts, lymphos - FHA for attachment.
- Tracheal cytotoxin kills ciliated cells
What are the three stags of Whooping cough?
- Catarrhal phase
- Paroxysmal phase
- Convalescent stage
What characterizes the catarrhal phase of whooping cough?
1-2 weeks, pt highly contagious
Low grade fever, runny nose, mild cough
Abx susceptible
What characterizes the paroxysmal phase of whooping cough?
2-10 weeks
Whooping non-productive cough
Increased # of lymphos
Abx ineffective
What is the vaccine for bordatella?
DaPT: diphtheria, acellular Pertusssis, and Tetanus. Given at 2,4,6,15 mos, and between 4-6 yrs.
What abx is useful in the catarrhal phase of bordatella?
erythromycin
What special medium does bordatella grow in?
Bordet-Gangou: potatoes, blood, and glycerol + PCN.
What two gram neg coccoids are also zoonotics?
Pasteurella (cat and dog bites) and brucella (unpasteurized dairy)
What are the sx of pasteurella?
Cellulitis, osteomyelitis.
What are the sx of brucellosis?
Undulant fever.
