Other Gram Negatives

Question 1

3 things to know about Moraxella catarrhalis

Answer 1

Colonizes airway • Can cause otitis media, COPD exacerbations

Usually treated empirically without micro diagnosis, b/c covered by most COPD exacerbation drugs

Question 2

Neisseria: Meningococcus vs Gonococcus

sugar stuff?

virulence factor?

treatment?

Answer 2

Both ferment glucose • _M_eningococcus ferments _M_altose • _G_onococcus ferments only _G_lucose • Both produce IgA protease • Ceftriaxone often used to treat both

Question 3

Neisseria Meningitidis

causes:

transmission:

Answer 3

Causes meningitis and meningococcemia

Transmitted by respiratory droplets

Enters pharynx then bloodstream then CSF • Many asymptomatic carriers

Question 4

whats unique about Neisseria Meningitidis?

vaccine?

Answer 4

Lipooligosaccharide (LOS) outer membrane

prevents phagocytosis

Vaccine available • Contains capsular polysaccharides → anti-capsule antibodies

Question 5

Neisseria Meningitidis when Bacteremia can complicate meningitis- Meningococcemia:

Answer 5

Sepsis: fevers, chills, tachycardia • Purpuric rash • DIC • Waterhouse-Friderichsen syndrome • Adrenal destruction from meningococcemia • Life-threatening

Question 6

whats Waterhouse-Friderichsen syndrome?

Answer 6

Adrenal destruction from meningococcemia

Question 7

Neisseria Meningitidis Infected patients require these precautions:

Answer 7

droplet precautions • Close contacts receive prophylaxis/vaccine • Rifampin • Also Ceftriaxone or Ciprofloxacin

Question 8

Recurrent NM Infections?

Answer 8

consider Terminal complement pathway deficiency- C5-C9 deficiency

Question 9

Key feature to know about Neisseria Gonorrhea:

Answer 9

• Key feature: antigenic variation of pilus proteins

so can never really have immunity against it

Question 10

Neisseria Gonorrhea causes: (5 things)

Answer 10

Mainly causes gonorrhea (STD) • Can also cause: • Pelvic inflammatory disease (PID) • Septic arthritis • Neonatal conjunctivitis • Fitz-Hugh-Curtis syndrome

Question 11

Gonorrhea: Pelvic inflammatory disease:

Answer 11

• Infection ascends (uterus, ducts, ovaries) • Pelvic/abdominal pain • Dyspareunia • Cervical motion tenderness on exam (chandelier sign) • High risk of subsequent ectopic pregnancy, infertility

Question 12

Gonorrhea Fitz-Hugh-Curtis:

what is it? classic finding in OR?

Answer 12

Perihepatitis • Inflammation of Glisson’s capsule around liver • Severe RUQ tenderness with pleuritic pain • “Violin string” adhesions of parietal peritoneum to liver

Question 13

Gonorrhea Septic Arthritis Key scenerio:

Answer 13

• Disseminated gonococcal infection (0.5 to 3%) • Septic arthritis •

Key scenario: • Sexually active young person • Swollen, warm and painful knee

Question 14

Neonatal Conjunctivitis Gonorrhea Prophylaxis:

Answer 14

• Prophylaxis: Erythromycin ophthalmic ointment

Question 15

Chlamydia microbio info:

Answer 15

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

Question 16

Chlamydia Treatment:

Answer 16

azithromycin, doxycycline (Protein synthesis inhibitors)

Question 17

Chlamydia Two phases to life cycle:

Answer 17

1: Elementary body (small, dense) • Enters cell via endocytosis

Question 18

3 types of Chlamydia:

Answer 18

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

Question 19

difference between chlamydia infection and gonerrhea infection in newborns?

Answer 19

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

Question 20

chlamydia can trigger Reactive Arthritis:

Classic Triad

Answer 20

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

Question 21

Lymphogranuloma Venereum is:

Answer 21

Chlamydia infection that enters lymphatics:

Initially: Genital ulcer • Sometimes unnoticed; Resolves

Later: Tender inguinal or femoral lymph nodes

Question 22

Trachoma definition:

Answer 22

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

Question 23

Campylobacter:

ox?

VERY common cause of:

transmission? Lives in :

Common trigger of

Answer 23

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

Question 24

Vibrio Cholera:

toxin?

causes famous type of diarrhea:

Answer 24

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)

Question 25

Haemophilus influenza

colonizes?

causes?

capsule?

vaccine?

Answer 25

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

Question 26

Special Features of Haemophilus influenza

Answer 26

IgA protease virulence factor

Grows on Chocolate agar • Factors V (NAD) and X (hematin) present • Will also grow with S. Aureus on blood agar

Question 27

Haemophilus influenza Infections (6)

Answer 27

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

Question 28

4 types of Genital Ulcers

Answer 28

Question 29

Bordetella Pertussis

classic presentation:

transmission

toxin:

Answer 29

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)

Question 30

Yersinia Enterocolitica

found:

often transmitted:

symptoms

Answer 30

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)!