Other gram negatives Flashcards
1
Q
Moraxella catarrhalis
A
- gram neg diplococci
- colonized airways
- can cause otitis media, COPD exacerbations
- Usually treated empirically without microdiagnosis
- not in most lab algorithms
- non-virulent strains of Neisseria comon airway flora
2
Q
Neisseria sp
A
N gonorrhea
N meningitidis
3
Q
how to tell which Neisseria
A
- Both ferment glucose but
- Meningococcus ferments maltose
- gonococcus ferments only glucose
- Both produce IgA protease
4
Q
Neisseria treatment
A
Ceftriaxone used to treat gonorrhea and menigitides
5
Q
Neisseria meningitidis
A
- causes meningitis and meningococcemia
- transmitted by respiratory droplets
- Enters pharyx then blood stream then CSF
- Many asymptomatic carriers
- virulent strains have polysaccharde capsule that prevents phagocytosis
- Lipooligosaccharide outer membrane (LOS) acts just like LPS on enteric gram neg rods
- Vaccine available
- contains capsular polysaccharides -> anti-capsule anti-bodies
6
Q
Meningococcemia
A
- bacteremia that can complicate N meningitis
- sepsis
- fevers
- chills
- tachycardia
- purpuric rash
- DIC
- Waterhouse-Friderichsen syndrome
- adrenal dysfunction from meningococcemia
- Life-threatening!
7
Q
Neisseria meningitidis treatment
A
- Spread via droplets so take droplet precautions (mask)
- Prophylaxis:
- Rifampin
- Also Ceftriaxone or ciprofloxacin
*
8
Q
Complement pathway deficiency
A
Nesseria meningitidis
C5-C9 deficiency
recurrent Nm infections
most often meningitis
9
Q
N gonorrhea illnesses
A
- mainly causes gonorrhea
- can also cause
- PID
- septic arthritis
- Neonatal conjunctivitis
- Fitz-Hugh-Curtis syndrome
10
Q
N gonorrhea key virulence feature
A
- antigenic variation of pilus proteins resulting in no long-term immunity after infection
- Re-infection likely
- No vaccine
11
Q
Gonorrhea
A
- most men/women with gonorrrhea are asymptomatic
- N. gonorrhea and Chlamydia often co-infect
- both can cause similar symptoms
- treat for both (Ceftriaxone, Azithromycin/Doxycycline)
- Men
- Dysuria, discharge
- epididymitis/orchitis
- Women
- itching, purulent discharge from cervix
- not painful
- can progress to PID
12
Q
Pelvic inflammatory disease
A
- gonorrhea infection ascends to uterus, ducts and ovaries
- pelvic/abdominal pain
- Dyspareunia
- Cervical motion tenderness on exam (chandelier sign)
- High risk of subsequent ectopic pregnancy, infertility
13
Q
Fitz-hugh-curtis
A
Gonorrhea
- perihepatitis
- inflammation of Glisson’s capsule around liver
- Severe RUQ tenderness with pleurtic pain
- Violin string adhesions of parietal peritoneum to liver
14
Q
Septic arthritis
A
- gonorrhea
- disseminated gonococcal infection (0.5-3%)
- key scenario
- sexually active young person
- swollen, warm and painful knee
15
Q
Neonatal conjunctivitis AKA
A
Ophthalmia neonatorum
16
Q
Neonatal conjunctivitis
A
- caused by Gonorrhea or chlamydia
- swelling and discharge from the eye
- 5 to 14 days after birth
- untreated can lead to visual impairment
- prophylaxis: erythromycin ophthalmic ointment
- new born prophylaxis mandated by many states
17
Q
Chlamydia features
A
- obligate intracellular organisms
- cannot make their own ATP
- cell wall lacks muramic acid
- N-acetylmuramic acid (NAM) in peptidoglycan
- cell wall lacks peptidoglycan
- does not gram stain well but are technically gram negative
- Giemsa stain
18
Q
Chlamydia treatment
A
- Penicillins do not work
- Ceftriaxone (for gonorrhea) ineffective
- Azithromycin or Doxycycline (protein synthesis inhibitors)
19
Q
Chlamydia life-cycle
A
2 phases
- Elementary body (small, dense)
- enters cell via endocytosis
- Reticulate body
- replicates in cells by fission
- can be seen in tissue culture
- Elementary bodies and reticular bodies grow, multiply and eventually rupture the cell and disperse
20
Q
Types of Chlamydia bacteria
A
- C. trachomatis (sexually-transmitted)
- C. pneumonia (atypical pneumonia)
- C. psittaci (Parrot fever)
21
Q
Chlamydia trachomatis illnesses
A
- Nongonococcal urethritis
- PID
- Conjunctivitis
- Reactive arthritis
22
Q
Chlamydiophila pneumonia illnesses
A
- Atypical pneumonia
- Transmitted by aerosol
23
Q
Chlamydiaphila Psittaci illnesses
A
- Psittacosis (Parrot fever)
- infection from birds
24
Q
Nongonococcal urethritis
A
- Caused by Chlamydia trachomatis
- sexually transmitted
- Often asymptomatic in men & women
- women
- cervicitis
- clear discharge, post-coital bleeding
- can progress to PID, Fitz-Hugh-Curtis
- cervicitis
- Men
- dicharge
- dysuria
25
Q
Nongonococcal urethritis treatment
A
- want to treat for chlamydia and gonorrhea
- Chlamydia
- Azithromycin/doxycycline
- Gonorrhea
- Ceftriaxone
- Chlamydia
26
Q
Newborn chlamydial infection
A
- infection from passage through the birth canal
- conjunctivitis
- similar to gonorrhea
- Pneumonia
- 4-12 weeks old
- classic feature is “Staccato cough”
- Inspiration between each single cough
- often have history of conjunctivitis
27
Q
C. trachomatis diagnosis
A
- Nucleic Acid Amplification Test (NAAT)
- PCR of chlamydia DNA/RNA
- Gold standard
- Culture and staining
- no longer routinely done
- Giemsa stain
- Chlamydial inclusion bodies in cytoplasm of epithelial cells
28
Q
Reactive arthritis
A
- Autoimmune arthritis
- triggered by infection (Chlamydia, but also intestinal infections (salmonella, Shigella, Campylobacter, Yersinia, C. difficile))
- 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
- Treatment
- NSAIDs
29
Q
Lymphogranuloma venereum
A
- Chlamydia infection that enters the lymphatics (different serotypes from those that cause urethritis)
- sexually transmitted
- Initially: genital ulcer (sometimes unnoticed, resolves)
- Later: Tender inguinal or femoral lymph nodes
- Treatment:
- Drainage
- Abx (azithromycin/doxycycline)
30
Q
Trachoma
A
- Caused by Chlamydia trachomatis (unique serotypes)
- Mostly in Africa and other developing parts of the world
- Highly contagious
- spread by contact with eye secretions
- acutely causes conjunctivitis
- Repeated infections -> corneal scarring -> blindness
- Leading cause of infectious blindness worldwide
31
Q
Chlamydia serotypes A, B, C
A
- Trachoma, blindness Africa
32
Q
Chlamydia serotypes D - K
A
- Urethritis
- PID
- neonatal pneumonia
- neonatal conjunctivitis
33
Q
Chlamydia serotypes L1, L2, L3
A
Lymphogranuloma venereum
34
Q
Campylobacter sps
A
- C jejuni
- C. coli
35
Q
Campylobacter features
A
- faint gram negative spiral, curved rod (comma shaped)
- oxidase positive
- Microaerophilic
- requires oxygen but lives best with low O2 levels
36
Q
Campylobacter illnesses
A
- very common cause of 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
37
Q
Vibrio cholera features
A
- toxin-mediated disease
- toxin carried by bacteriophage (lysogenic)
- permanently activates Gs -> increase cAMP
- Voluminous “rice-water” diarrhea
- requires large dose of bacteria for infection
- stomach acid kills bugs
- common in areas that lack clean water
- also can occur on acid suppression drugs (lower req’d dose)
- death from dehydration, electrolyte losses, shock
- Treatment: aggressive volume repletion
38
Q
Vibrio vulnificus/parahaemolyticus
A
- Both cause food poisoning (diarrhea)
- raw oysters
- V. vulnificus can infect wounds after swimming in contaminated water
39
Q
Haemophilus influenza
A
- Gneg colonizes nasopharynx
- causes several respiratory diseases, meningitis
- some have polysaccharide capsule and some dont
- capsular are typeable into 6 serotypes (a to f)
- others are nontypeable
- Most disease is caused by serotype 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
40
Q
Haemophilus influenza special features
A
- Produces IgA protease
- Grows on chocolate agar
- Factors V (NAD) and X (hematin) present
- will also grow with Staph aureus on blood agar
41
Q
Haemophilus influenza illnesses
A
- Epiglottitis in children
- Pneumonia
- Meningitis
- Otitis media
- Bronchitis
- Conjunctivitis
42
Q
Epiglottitis
A
- life-threatening illness caused by H. flu (airway obstruction
- unvaccinated children with fever and sore throat
- Dysphagia, drooling
- epiglottis will appear “cherry red”
43
Q
H. influenzae vaccine doesn’t protect against
A
- more commonly caused by strep pneumoniae but H. flu can also cause this
- Otitis media
- Bronchitis
- Conjunctivitis
44
Q
Haemophilus ducreyi
A
- causes chancroid
- painful genital ulcer
- contrast with Chancre (syphilis): non painful
- sexually transmitted
- Tx
- Azithromycin/Ceftriaxone
45
Q
Causes and features of genital ulcers
A
- Syphilis
- painless chancre
- H. ducreyi
- Painful chancroid
- Herpes
- Multiple vesicles/ulcers
- Lymphogranuloma venereum
- large swollen lymph nodes (buboes)
46
Q
Bordetella pertussis
A
- Vaccination available so not common anymore
- Causes whooping cough
- URI with severe coughing
- classic presentations
- Paroxysms of coughing
- Inspiratory “whoop”
- Post-cough vomiting
- Exhaustion from coughing
- coughing fits last weeks
- Known as the 100-day cough
47
Q
Bordetella pertussis features
A
- Transmitted by aerosolized droplets
- Pertussis toxin
- Shown to inhibit Gi proteins
- Allows over-activation of adenylate cyclase
- increase cAMP levels in cells in neutrophils
- result: impaired recruitment of neutrophils
- Toxin may not be the cause of cough
- some species without toxin also cause symptoms
48
Q
Bordetella pertussis vaccine
A
- acellular pertussis vaccines used
- contain purified pertussis antigens
49
Q
Yersinia enterocolitica features
A
- found in domesticated animals (dogs) and 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 Crohns or appendicitis
- dont confuse with Yersinia pestis (plague)
