Other Gram Negatives Flashcards
3 things to know about Moraxella catarrhalis
Colonizes airway • Can cause otitis media, COPD exacerbations
Usually treated empirically without micro diagnosis, b/c covered by most COPD exacerbation drugs
Neisseria: Meningococcus vs Gonococcus
sugar stuff?
virulence factor?
treatment?
Both ferment glucose • _M_eningococcus ferments _M_altose • _G_onococcus ferments only _G_lucose • Both produce IgA protease • Ceftriaxone often used to treat both
Neisseria Meningitidis
causes:
transmission:
Causes meningitis and meningococcemia
Transmitted by respiratory droplets
Enters pharynx then bloodstream then CSF • Many asymptomatic carriers
whats unique about Neisseria Meningitidis?
vaccine?
Lipooligosaccharide (LOS) outer membrane
prevents phagocytosis
Vaccine available • Contains capsular polysaccharides → anti-capsule antibodies
Neisseria Meningitidis when Bacteremia can complicate meningitis- Meningococcemia:
Sepsis: fevers, chills, tachycardia • Purpuric rash • DIC • Waterhouse-Friderichsen syndrome • Adrenal destruction from meningococcemia • Life-threatening
whats Waterhouse-Friderichsen syndrome?
Adrenal destruction from meningococcemia
Neisseria Meningitidis Infected patients require these precautions:
droplet precautions • Close contacts receive prophylaxis/vaccine • Rifampin • Also Ceftriaxone or Ciprofloxacin
Recurrent NM Infections?
consider Terminal complement pathway deficiency- C5-C9 deficiency
Key feature to know about Neisseria Gonorrhea:
• Key feature: antigenic variation of pilus proteins
so can never really have immunity against it
Neisseria Gonorrhea causes: (5 things)
Mainly causes gonorrhea (STD) • Can also cause: • Pelvic inflammatory disease (PID) • Septic arthritis • Neonatal conjunctivitis • Fitz-Hugh-Curtis syndrome
Gonorrhea: Pelvic inflammatory disease:
• Infection ascends (uterus, ducts, ovaries) • Pelvic/abdominal pain • Dyspareunia • Cervical motion tenderness on exam (chandelier sign) • High risk of subsequent ectopic pregnancy, infertility
Gonorrhea Fitz-Hugh-Curtis:
what is it? classic finding in OR?
Perihepatitis • Inflammation of Glisson’s capsule around liver • Severe RUQ tenderness with pleuritic pain • “Violin string” adhesions of parietal peritoneum to liver
Gonorrhea Septic Arthritis Key scenerio:
• Disseminated gonococcal infection (0.5 to 3%) • Septic arthritis •
Key scenario: • Sexually active young person • Swollen, warm and painful knee
Neonatal Conjunctivitis Gonorrhea Prophylaxis:
• Prophylaxis: Erythromycin ophthalmic ointment
Chlamydia microbio info:
Obligate intracellular organisms because cannot make their own ATP • Cell wall lacks muramic acid • N-acetylmuramic acid (NAM) in peptidoglycan • Cell wall lacks peptidoglycan • Do not gram stain well (technically gram negative) • Giemsa stain
Chlamydia Treatment:
azithromycin, doxycycline (Protein synthesis inhibitors)
Chlamydia Two phases to life cycle:
1: Elementary body (small, dense) • Enters cell via endocytosis
3 types of Chlamydia:
Chlamydia trachomatis (sexually transmitted) • Nongonococcal urethritis • PID • Conjunctivitis • Reactive arthritis
Chlamydophila pneumonia • Atypical pneumonia • Transmitted by aerosol
Chlamydophila psittaci • Psittacosis (Parrot fever) • Infection from birds
difference between chlamydia infection and gonerrhea infection in newborns?
Infection from passage through birth canal • Conjunctivitis • Similar to Gonorrhea
DIFFERENCE: Pneumonia • 4-12 weeks old • Classic feature is “staccato cough” • Inspiration between each single cough • Often have a history of conjunctivitis
chlamydia can trigger Reactive Arthritis:
Classic Triad
Autoimmune arthritis • Triggered by infection
Classic triad (Reiter’s syndrome) • Arthritis (often unilateral, lower extremities, knees, toes) • Conjunctivitis (red eye, discharge) • Urethritis (dysuria, frequency – noninfectious)
Diagnosis: Classic features following typical infection
Lymphogranuloma Venereum is:
Chlamydia infection that enters lymphatics:
Initially: Genital ulcer • Sometimes unnoticed; Resolves
Later: Tender inguinal or femoral lymph nodes
Trachoma definition:
Chlamydia Eye Disease
Highly contagious • Spread by contact with eye secretions • Acutely causes conjunctivitis • Repeated infections → Corneal scaring → blindness • Leading cause of infectious blindness worldwide
Campylobacter:
ox?
VERY common cause of:
transmission? Lives in :
Common trigger of
Oxidase positive
VERY common cause acute diarrhea in children
A leading cause of acute diarrhea worldwide
Fecal-oral transmission • Lives in animal intestines, especially poultry • Undercooked meat especially poultry • Unpasteurized milk • Can also contaminate drinking water
Common trigger of Guillain-Barre • Demyelinating disease • Ascending weakness
Vibrio Cholera:
toxin?
causes famous type of diarrhea:
Toxin-mediated disease
Toxin carried by bacteriophage (lysogenic) • Permanently activates Gs → ↑cAMP
Voluminous “rice-water” diarrhea
Requires large “dose”
Acid kills small amounts of bacteria • Common in areas that lack clean water • Also can occur on acid suppression drugs (lowers dose req’d)
Haemophilus influenza
colonizes?
causes?
capsule?
vaccine?
Colonizes nasopharynx • Causes several respiratory diseases, meningitis • Some have polysaccharide capsule some do not • “Capsular” bacteria are “typeable” into six serotypes (a to f) • Others are “nontypeable” • Most disease caused by type B • Capsule consists of ribosyl and ribitol phosphate polymer
Vaccine contains type B capsule (Hib) • Conjugated to a carrier protein (often tetanus toxoid) • Stronger T-cell response • Given before 7 months
Special Features of Haemophilus influenza
IgA protease virulence factor
Grows on Chocolate agar • Factors V (NAD) and X (hematin) present • Will also grow with S. Aureus on blood agar
Haemophilus influenza Infections (6)
Epiglottitis • Life-threatening (airway obstruction) • Unvaccinated children with fever, sore throat • Dysphagia, drooling • Epiglottis will appear “cherry red”
Pneumonia
Meningitis
Otitis media, bronchitis, conjunctivitis • S. pneumoniae and non-typeable H. influenza • Vaccine not protective
4 types of Genital Ulcers
Bordetella Pertussis
classic presentation:
transmission
toxin:
Causes whooping cough • URI with severe coughing
Classic presentations • Paroxysms of coughing • Inspiratory “whoop” • Post-cough vomiting • Exhaustion from coughing • Coughing fits can last weeks • In China, pertussis known as the “100 day cough
Transmitted by aerosolized droplets
Pertussis toxin • Shown to inhibit Gi proteins • Allows over-activation of adenylate cyclase • ↑cAMP levels in cells in neutrophils • Result: impaired recruitment of neutrophils
(note: Toxin may not be cause of cough • Some species without toxin shown to cause symptoms)
Yersinia Enterocolitica
found:
often transmitted:
symptoms
Found in domesticated animals (dogs), pigs
Often transmitted through contaminated pork • Also from contaminated water or milk
Fever, abdominal pain, nausea, vomiting • Bloody diarrhea • Can cause inflammation around appendix or in mesenteric lymph nodes (mesenteric adenitis) • May mimic Crohn’s or appendicitis
Don’t confuse with Yersinia pestis (plague)!
