Phenotypic and genotypic characterisation of Streptococcus pneumoniae carriage strains from paediatric population in Arkhangelsk region, Russia

Abstract number: P1711

Vorobieva V., Furberg A., Bazhukova T., Lebedeva O., Haldorsen BC., Buaro L., Aasnaes B., Caugant D., Sundsfjord A., Simonsen GS.

Objectives: To determine the prevalence of the nasopharyngeal carriage of Streptococcus pneumoniae in children from Arkhangelsk region, Russia, and characterize the strains with regard to population structure and antimicrobial resistance.

Methods: A single nasopharyngeal (NP) swab from 438 non-vaccinated healthy children aged 1–7 years, at 10 day-care centres in the Arkhangelsk region in November 2006. S. pneumoniae isolates were identified by standard methods and examined for the susceptibility to oxacillin (OXA), tetracycline (TET), erythromycin (ERY), norfloxacin (NOR), and trimethoprim-sulfamethoxazole (TMP/SMX), with agar disk diffusion (Oxoid LTD, UK) using breakpoints defined by the Norwegian Working Group for Antibiotics (NWGA) and the Swedish Reference Group for Antibiotics (SRGA). OXA-resistant isolates were further examined for their susceptibility to penicillin G (PENG), cefuroxime, cefotaxime and meropenem by Etest. ERY-resistant isolates were examined by the double disk diffusion method with ERY and clindamycin (CLI) (Oxoid) as well as for erm(B) and mef-gen by PCRs. NOR-resistant isolates were examined by Etest for their susceptibility to ciprofloxacin (CIP), norfloxacin (NOR), moxifloxacin (MXE) and levofloxacin (LVX), using SRGA and EUCAST-breakpoints. Multi-drug resistance (MDR) was defined as resistance to geqslant R: gt-or-equal, slanted3 groups of antibiotics. Ongoing analyses of the population structure are performed by serotyping and MLST.

Results:S. pneumoniae was recovered from 171 (39%) NP-samples. The rates of non-susceptibility were: TMP/SMX (n = 143;84%), TET (n = 54;32%), OXA (n = 31;18%), ERY (n = 18;11%), and NOR (n = 1; <1%). 22/31 (71%) of OXA-resistant strains were conformed non-susceptible for PENG (range 0.094–1 mg/L). Double disk diffusion analysis of ERY-resistant strains (n = 16) revealed the following phenotypes: iMLSB(n = 9), cMLSB (n = 4), and M-type (n = 3), which was confirmed by erm(B) and mef(A)-PCRs. One NOR-resistant strain revealed the following MIC profile: NORgeqslant R: gt-or-equal, slanted32 mg/L, CIPgeqslant R: gt-or-equal, slanted4 mg/L, and susceptible to LVX (2 mg/L), MXE (0.25 mg/L). MDR was detected in 19 strains (11%).

Conclusions: (i)The prevalence of pneumococcal colonisation (39%) in children aged 1–7 years in Arkhangelsk is relatively high. (ii)High to moderate rates of non-susceptibility to commonly used antibiotics were observed: TMP/SMX (84%), TET (32%), PENG (13%) and ERY (11%) were observed. (iii)A low prevalence (<1%) of resistance to fluoroquinolones was observed.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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