Phenotypes and genotypes of macrolide-resistant Streptococcus pneumoniae in Serbia

Mirjana Hadnadjev,Ina Gajic,Anika Povazan,Tatjana Kurucin,Natasa Opavski,Aleksandra Vulin,Vera Mijac

doi:10.2298/abs1401099h

Abstract

Although macrolides are widely used for treating pneumococcal infections, an increase in macrolide resistance might compromise their use. The objective of this study was to determine the prevalence of macrolide-resistant phenotypes and genotypes in macrolide-resistant S. pneumoniae isolates in Serbia. A total of 228 macrolide-resistant strains isolated during the period of 2009-2012, were analyzed. Macrolide resistance phenotypes were determined by a double disk diffusion test. The presence of macrolide resistance genes was detected by PCR. Antibiotics susceptibilities were tested using the VITEK2 system and E test. Among the examined isolates, the MLSB phenotype which is linked to the presence of the erm(B) gene dominated (83.3%), while the mef(A) gene which is associated with the M phenotype, was identified in 16.7% isolates. Over 40% of isolates expressed co-resistance to penicillin. A multiple-resistant pattern was found in 36.4% strains, more frequently in children. However, all strains were susceptible to telithromycin, vancomycin, linezolid, fluoroquinolones and rifampicin.

Highlights

Streptococcus pneumoniae is a leading cause of diseases, inducing invasive and mucosal infections in both children and adults worldwide (Centers for Disease Control and Prevention, 2000; Robinson et al, 2001; Farha, 2005)
The aim of this study was to examine the prevalence of macrolideresistant phenotypes and genotypes among invasive and noninvasive macrolide-resistant S. pneumoniae isolates in Serbia
The results of our study showed that a constitutive MLSB phenotype predominates among macrolideresistant S. pneumoniae isolates in Serbia

Summary

Introduction

Streptococcus pneumoniae is a leading cause of diseases, inducing invasive (meningitis, septicemia, bacteremic pneumonia) and mucosal infections (otitis media, sinusitis) in both children and adults worldwide (Centers for Disease Control and Prevention, 2000; Robinson et al, 2001; Farha, 2005). Beta lactam and macrolide antibiotics have remained a first choice for the empirical treatment of pneumococcal infections (Whitney et al, 2000). In recent decades, the treatment of pneumococcal infections is becoming more difficult due to a global increase and expansion of pneumococcal resistance to these antibiotics. This is of particular importance, since strains exhibiting penicillin and macrolide are frequently resistant to other classes of antibiotics. The prevalence of resistance varies greatly among countries (Lynch et al, 2005)

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