engleski

Emergence of a macrolide-resistant serotype 19A pneumococcal strain in two croatian regions

Background and aims: Antibiotic resistance within Streptococcus pneumoniae represents a major health problem in many countries. Increase in pneumococcal resistance to macrolides is particularly high in Croatia in the last years and macrolide resistance raised significantly from 25% in 2005 to 40% in 2008. The aim of this study was to compare the distribution of serotypes among resistant strains collected in four Croatian regions. Methods: A total of 165 macrolide-resistant isolates were obtained from children under 16 years of age in different regions of Croatia (Zagreb, Rijeka, Osijek and Varazdin regions), with a mean age of three years. The macrolide-resistant isolates were collected in two month period (November 2009 till January 2010) from nasopharyngeal swabs, and serotyping of the strains was carried out by latex agglutination and Neufeld quellung test. Results: The most common serotypes were 19A (23.6%) and 19F (23.6%). Other serotypes (1, 2, 3, 4, 5, 8, 6A, 6B, 6C, 7, 8, 9, 10, 11, 14, 15, 17, 18C, 19C and 23F) were detected with a low frequency. The macrolide-resistance in strains collected in Osijek and Varazdin regions was associated with serotype 19A, and the resistance in strains collected in Zagreb and Rijeka regions was associated with serotype 19F (p<0.01). Conclusions: Serotype coverage for the 7-valent conjugate vaccine in Osijek and Varazdin regions is low (<20%) and emergence of a macrolide-resistant serotype 19A pneumococcal strain not included in 7-valent conjugate vaccine is detected.

Streptococcus pneumoniae; serotype 19A; macrolide resistance; vaccine

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