Emergence of a Clonal Lineage of Streptococcus agalactiae with resistance to fluoroquinolones among invasive isolates from Argentina recovered during 2014-2015.

ARIAS B; KOVACEC V; MULLER L; VIGLIAROLO L; SUAREZ M; TERSIGNI C; LOPARDO H; BONOFIGLIO L; MOLLERACH M

Valencia

Congreso; 7 th Congress of European Microbiologists; 2017

Federation of European Microbiological Societies

Background: Resistance to fluoroquinolones (FQ) in Streptococcus agalactiae (GBS) was firstly described in 2003. Currently, it has become a worldwide growing problem. Aims: To determine the prevalence of FQ resistance, the circulating clones among these isolates and to analyze their epidemiological characteristics.Methods: In the frame of a "national prospective multicenter study of S. agalactiae invasive infections in Argentina", 162 isolates were recovered between July 1, 2014 ?June 30, 2015. A five-disc scheme of levofloxacin, ciprofloxacin, norfloxacin, ofloxacin and pefloxacin was designed to detect FQ resistant isolates. MIC of levofloxacin was performed by agar dilution. Quinolone resistance determining regions were sequenced to detect mutations. Capsular typing was done using the Strep-B Kit. Pulsed-field gel electrophoresis (PFGE) was performed to investigate the genetic relationship of GBS-FQ-resistant isolates. Results: The prevalence of FQ resistance was 15.4% (25/162). All of the FQ resistant strains showed point mutations in gyrA and/or parC genes. One PFGE group (PFGE-A) accounted for 88% of the isolates (23/25) and included 13/23 isolates with identical pattern. PFGE-A clustered isolates from 9 Argentinean cities and were assigned to serotypes: Ib (14/23) and III (8/23). Conclusions:. The resistance rate (15.4 %) is higher than that found previously in our country and even in other countries of Latin America. FQ-resistant GBS isolates were recovered from different cities of Argentina and a major clone was detected. PFGE pattern is appesimilar to thos detected previously in Argentina and Japan