Lecture 17 - Molecular epidemiology and outbreak investigation Flashcards
(9 cards)
1
Q
describe the meningococcal outbreak involved in this study
A
- 2013-17 WA N meningitidis outbreak
- collected invasive isolates, E test for antibiotic susceptibility, WGS and phylogenetics
2
Q
describe the serogroup distributions in WA
A
- 2000-15 = vaccinated serogroup B + unvaccinated MenWcc11
- 2013-15 = few MenWcc11 + deaths
- 2016-17 = increasing MenWcc11 and deaths
3
Q
what does the label MenWcc11 stand for?
A
MenW serogroup + clonal complex 11 (STs)
4
Q
what was the antibiotic susceptibility of MenWcc11?
A
- all susceptible to ciprofloxacin and rifampin
- 68% resistant to penicillinn
- 1 reduced susceptibility for penicillin and ceftriaxone (first line treatment)
5
Q
what was the core genome analysis of the N meningitidis isolates?
A
- 1.5Mb core genome
- 1605 loci
- Cluster A and B
- Cluster B = more evolution
- ExNm672 outlier from Asia
6
Q
what was the antibiotic susceptibilities for cluster A and B?
A
- A = all penicillin sensitive
- B = intermediate susceptibility or resistant
- A and B = ceftriaxone sensitive
7
Q
what are the mechanisms of penicillin resistance iin meningococci? Include the ExNm672 outlier
A
- plasmid = beta-lactamase
- chromosome PBP1-3 mutations = penA, ponA, pbp3
- penA = alleles 59 and mutated 253 = intermediate and resistant
- ExNm672 outlier = penA 1281 allele = PBP2 variant = reduced suscep to penicillin/ceftriaxone
8
Q
What was the global phylogenetic tree patterns for MenWcc11?
A
- cluster A = UK, south america
- cluster B = unique to WA
- ExNm672 outlier alone
9
Q
what was this study’s summary?
A
- MenWcc11 WA cases doubling annually
- 7 STs + 11 isolates = on site evolution and clonal expansion
- core genome = 2 clusters based onpenicillin suscep
- cluster B = penicillin resistant/insensitive
- penA 253 = pen resistant + ceft sensitive
- penA 1281 = pen and ceft resistant
