[Epidemiology, clinical and microbiological characteristics of invasive streptococcal infections in Turkey, 2010-2011]

Abstract

A one-year active surveillance study was conducted to investigate the epidemiological and microbiological characteristics of invasive group A streptococci (GAS) infections in Turkey and to provide data for the establishment of national preventive strategies related to invasive GAS infections. A total of 46 clinical microbiology laboratories from 12 different regions of Turkey (Istanbul; Eastern and Western Marmara; Eastern and Western Blacksea; Aegean; Mediterranean; Western, Central, Northeastern, Middle-eastern and Southeastern Anatolia) participated in the study. Accordingly, GAS strains isolated from sterile body sites (blood, cerebrospinal, synovial, pleural, peritoneal, pericardial fluids) in the study centers between June 2010-June 2011, were sent to Maltepe University Hospital Clinical Microbiology Laboratory for microbiological confirmation and further analysis. The isolates were identified by conventional methods, and for serotyping, opacity factor (OF) and T protein types were investigated. For genotyping GAS lysate preparation, emm gene amplification and sequencing were performed by using the protocols recommended by Centers for Disease Control and Prevention. A total of 65 invasive GAS strains were isolated in 15 of the participant centers, during the study period. The rate of invasive GAS isolation exhibited regional variation, with the highest rates in the Eastern Blacksea (Trabzon, n= 19), followed by Istanbul (n= 17) and Western Anatolia (Ankara, Konya, n= 14). Of the patients with invasive GAS infection 33 were female, 32 were male, with the age range of 0-89 years. GAS strains were most commonly isolated from soft tissue specimens (n= 18), followed by abscess material (n= 10), sterile body fluids (n= 8) and blood (n= 7) samples. Serotyping revealed that 55% (36/65) of the strains were OF positive, and the majority of T protein was polygroup T (n= 20), followed by U (n= 14), B (n= 5), X (n= 3) and Y (n= 2). T protein was not detected in 22 isolates. The strains were found to have 17 different emm types;emm1 (n= 13), emm4 (n= 6), emm6 (n= 6), emm12 (n= 6), emm24 (n= 4), emm14 (n= 3) and emm28 (n= 3). Nine of the strains could not be typed by sequencing. The correlation between emm typing and serotyping was detected as 58%. It was observed that 26-valent vaccines included 70.5% of the invasive GAS strains included in this study. Our study provided initial data concerning the epidemiological properties of invasive GAS infections and characterization of GAS strains in Turkey. The incidence of invasive GAS infections is low in our country. Although immunization programme by 26-valent GAS vaccine is not currently an urgent public health issue for our country, the results of this study indicated that emm types 4 and 24 should better be included in such a vaccine to be used in Turkey. Additionally, since epidemiological features of GAS infections and the microbiological characteristics of the strains can vary by time, for the diagnosis of invasive streptococcal infections and to take the necessary preventive measures, epidemiological studies should be conducted repeatedly.