title: Molecular epidemiology of penicillin-susceptible non-beta-lactam-resistant Streptococcus pneumoniae isolates from Greek children.
abstract: A total of 128 Streptococcus pneumoniae isolates that were susceptible to penicillin but resistant to non-beta-lactam agents were isolated from young carriers in Greece and analyzed by antibiotic susceptibility testing, serotyping, restriction fragment end labeling (RFEL), and antibiotic resistance genotyping. The serotypes 6A/B (49%), 14 (14%), 19A/F (11%), 11A (9%), 23A/F (4%), 15B/C (2%), and 21 (2%) were most prevalent in this collection. Of the isolates, 65% were erythromycin resistant, while the remaining isolates were tetracycline and/or trimethoprim-sulfamethoxazole resistant. Fifty-nine distinct RFEL types were identified. Twenty different RFEL clusters, harboring 2 to 19 strains each, accounted for 76% of all strains. Confirmatory multilocus sequence typing analysis of the genetic clusters showed the presence of three international clones (Tennessee(23F)-4, England(14)-9, and Greece(6B)-22) representing 30% of the isolates. The erm(B) gene was present in 70% of the erythromycin-resistant isolates, whereas 18 and 8% contained the mef(A) and mef(E) genes, respectively. The pneumococci representing erm(B), erm(A), and mef genes belonged to distinct genetic clusters. In total, 45% of all isolates were tetracycline resistant. Ninety-six percent of these isolates contained the tet(M) gene. In conclusion, penicillin-susceptible pneumococci resistant to non-beta-lactams are a genetically heterogeneous group displaying a variety of genotypes, resistance markers, and serotypes. This suggests that multiple genetic events lead to non-beta-lactam-resistant pneumococci in Greece. Importantly, most of these genotypes are capable of disseminating within the community.
authors.affiliation: Department of Pediatrics, Sophia Children's Hospital, Erasmus MC Rotterdam, 3000 DR Rotterdam, The Netherlands.
authors.forename: D
authors.initials: D
authors.lastname: Bogaert
authors.forename: P W M
authors.initials: PW
authors.lastname: Hermans
authors.forename: I N
authors.initials: IN
authors.lastname: Grivea
authors.forename: G S
authors.initials: GS
authors.lastname: Katopodis
authors.forename: T J
authors.initials: TJ
authors.lastname: Mitchell
authors.forename: M
authors.initials: M
authors.lastname: Sluijter
authors.forename: R
authors.initials: R
authors.lastname: De Groot
authors.forename: N G
authors.initials: NG
authors.lastname: Beratis
authors.forename: G A
authors.initials: GA
authors.lastname: Syrogiannopoulos
mesh_terms: D002353:Carrier State / Q000382:microbiology; D002648:Child; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D004917:Erythromycin / Q000494:pharmacology; D006115:Greece / Q000453:epidemiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D010403:Penicillin Resistance / Q000235:genetics; D010802:Phylogeny; D012703:Serotyping / Q000379:methods; D013290:Streptococcal Infections / Q000453:epidemiology*; D013296:Streptococcus pneumoniae / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D018440:beta-Lactam Resistance / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D004917:Erythromycin