title: Antimicrobial resistance in colonizing group B Streptococci before the implementation of a Swedish intrapartum antibiotic prophylaxis program.
abstract: The prevalence of antibiotic resistance and their genetic determinants in colonizing group B streptococci (GBS) sampled in a Swedish nationwide survey was examined. In five GBS isolates (1.3%), kanamycin/amikacin resistance and the presence of the aphA-3 gene was identified. Three of these isolates carried the aad-6 gene and were streptomycin-resistant. Screening with kanamycin and streptomycin 1,000-μg disks enabled a rapid and easy detection of these isolates. In all, 312/396 (79%) GBS were tetracycline-resistant and 95% of the examined isolates harbored the tetM gene. Among the 22 (5.5%) GBS resistant to erythromycin and/or clindamycin, the ermB gene was detected in nine isolates (41%) and erm(A/TR) in ten isolates (45%). A high level of erythromycin and clindamycin resistance with minimum inhibitory concentrations (MICs) >256 mg/L was found in four serotype V isolates that harbored ermB. The erythromycin/clindamycin resistance was distributed among all of the common serotypes Ia, Ib, II, III, IV, and V, but was not present in any of the 44 serotype III isolates associated to clonal complex 17. Screening for penicillin resistance with 1-μg oxacillin disks showed a homogenous population with a mean inhibition zone of 20 mm. A change in the present oxacillin breakpoints for GBS is suggested.
authors: Department of Clinical Bacteriology, Umeå University Hospital, 901 85 Umeå, Sweden. Margareta.Granlund@climi.umu.se
authors: M
authors: M
authors: Granlund
authors: P
authors: P
authors: Axemo
authors: K
authors: K
authors: Bremme
authors: A-L
authors: AL
authors: Bryngelsson
authors: M
authors: M
authors: Carlsson Wallin
authors: C-M
authors: CM
authors: Ekström
authors: S
authors: S
authors: Håkansson
authors: B
authors: B
authors: Jacobsson
authors: K
authors: K
authors: Källén
authors: E
authors: E
authors: Spetz
authors: I
authors: I
authors: Tessin
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015373:Bacterial Typing Techniques; D002353:Carrier State / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial; D005260:Female; D005798:Genes, Bacterial; D006801:Humans; D007231:Infant, Newborn; D008826:Microbial Sensitivity Tests / Q000379:methods; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000382:microbiology*; D012007:Rectum / Q000382:microbiology; D012703:Serotyping; D012867:Skin / Q000382:microbiology; D013290:Streptococcal Infections / Q000382:microbiology*; D013292:Streptococcus agalactiae / Q000187:drug effects* / Q000302:isolation & purification; D013548:Sweden; D014621:Vagina / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial