Gram negative cocci and Spirochetes

Question 1

Genus Neisseria morphology

Answer 1

Gram Negative diplococci

Question 2

Genus Neisseria features

Answer 2

• no flagella
• pili/fimbriae
• strict parasites
• oxidase positive, most are catalase positive

Question 3

Genus Neisseria oxygen requirements

Answer 3

aerobic or microaerophilic

Question 4

Neisseria gonorrhoeae virulence factors

Answer 4

• Pili for conjugation, attachments, and neutrophil resistance (slow phagocytosis)
• Porin B– interfere neutrophil degranulation
• IgA protease–cleaves IgA
• Endotoxin
• Antigenic variation (serotypes)

Question 5

*Neisseria gonorrhoeae** Epidemiology and Pathology

Answer 5

• only infect humans though direct touch of bodily fluids, does not last on fomites for more than 1 hour
  -infectious dose is 100-1,000 (males)
  -Top 5 STIs, rising in cases
  -

Question 6

Gonorrhea in Males

Answer 6

• Symptomatic 90% of the time (genital)
  – urethritis, yellowish discharge, scarring, infertility
• extragenital infections- anal oral, conjunctivitis, septicemia, arthritis, skin lesions

Question 7

Gonorrhea in Females

Answer 7

-50% asymptomatic, 50% discharge
– vaginitis, urethritis, salpingitis (PID), mixed infections with anaerobes, common cause of infertility and ectopic tubal pregnancy
- extragenital infection, same as men

Question 8

Gonorrhea in Newborns

Answer 8

• passed through the birth canal
• eye inflammation, blindness, rarely more

Question 9

Prevention of Gonorrhea in Newborns

Answer 9

Prophylactic eye drops immediately after birth

Question 10

Neisseria gonorrhoeae Diagnosis and Control

Answer 10

• sample from urethral, vaginal, cervical, or eye exudate –if shows Gram negative diplococci is a presumptive diagnosis
• Can get infected many times
• Is a reportable disease

Question 11

Neisseria gonorrhoeae Medication and Resistance

Answer 11

• Many strains resistance
  -Ceftriaxone main reliable treatment
  -with even more rising resistance- soon to be untreatable

Question 12

Neisseria meningitidis Virulence factors

Answer 12

• capsule
  -Adhesive fimbriae
  -IgA protease
• Endotoxin

Question 13

Neisseria meningitidis strains

Answer 13

• 12 strains capsular Antigens; serotypes A,B,C,Y,W most common

Question 14

Neisseria meningitidis Epidemiology and Pathogenesis

Answer 14

• common cause of meningitis (sporadic or epidemic)
• human reservior, nasopharynx
• spreads easily through close living qaurters
• most at risk is children 6months- 3 years and young adults
  -very rapid onset, can be fatal

Question 15

Neisseria meningitidis symptoms

Answer 15

-neurological symptoms, endotoxins cause hemorrhage and shock,
-can be fatal
- permanent damage 10-20%

Question 16

Meningococcemia

Answer 16

• bacteria replicates in the bloodstream
• endotoxin causes hemorrhage and petechiae
• shock can be fatal within a few hours of onset of symptoms
  -fluid-filled bubbles

Question 17

Clinical Diagnosis of Meningococcemia (5)

Answer 17

-Gram stain from CSF (Cerebrospinal fluid) or nasopharyngeal
- Culture for differentiation, antibiotic susceptibility
-oxidase positive
-rapid test for capsular polysaccharides (tests for serotypes)
- PCR

Question 18

Meningococcal Treatment

Answer 18

• IV or IM penicillin G, Chloramphenicol, or some cephalosporins (resistance, or allergies)

Question 19

Meningococcal Prevention

Answer 19

• Prophylactic for those in close contact (health care)
• Vaccines
  –conjugate- capsular Ags from A,C, W and Y
  –Recombinant proteins for B only
  vaccine for high risk (16-23)

Question 20

Gram negative cocci species of relevance

Answer 20

Neisseria gonorrhoeae
Neisseria meningitidis

Question 21

Spirochetes Genera

Answer 21

Treponema
Borrelia
Leptospira

Question 22

Spirochetes characteristics

Answer 22

-most are commensal, not primary pathogens
- Gram-negative
– But lacks typical LPS, have lipoproteins

Question 23

Genus Treponema characteristics

Answer 23

• thin, regular coiled cells
• Periplasmic flagella
• mainly strict parasites
  – require live cells for cultivation
  -some only glycolysis
  -small genome (1,000 genes)

Question 24

Genus Treponema normal flora locations

Answer 24

oral cavity, intestinal tract, perigenital regions of humans and animals

Question 24

Genus Treponema oxygen requirements

Answer 24

microaerophilic or anaerobic

Question 25

Treponema pallidum subspecies pallidum main disease

Answer 25

syphilis (great pox)

Question 25

Treponema pallidum subspecies pallidum characteristics

Answer 25

-human-only host
- extremely fastidious and sensitive & cannot survive outside the host
- doubling time 30 hours
- transplacental
- few species have specific surface Ags
- Outer membrane proteins for adherence and inhibit phagocytosis