Abstract

Background: Streptococcus agalactiae or group B Streptococcus (GBS) is an important pathogen in neonates and nonpregnant individuals. Epidemiological studies of GBS resistance to fluoroquinolones (FQs) in Latin America are scarce. This study aimed to determine the local prevalence of FQ resistance in the frame of a national, prospective multicenter study of invasive GBS infections and to investigate mechanisms of resistance, serotype distribution, and clonal relationships among resistant isolates. Methods: From July 2014 to July 2015, 162 invasive GBS isolates were collected from 86 health care centers in 32 Argentinean cities. All isolates were screened for FQ nonsusceptibility using a five-disc scheme: levofloxacin (LVX), ciprofloxacin, norfloxacin (NOR), ofloxacin, and pefloxacin (PF). LVX minimal inhibitory concentration (MIC) was determined by the agar dilution method. Sequencing of internal regions of gyrA and parC genes was performed. Capsular typing and genetic characterization of nonsusceptible isolates were assessed by latex agglutination, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing. Results: Twenty-four of one hundred sixty-two GBS isolates exhibited no inhibition zones to all tested FQs with an MIC range of 16-32 mg/L for LVX, and one isolate with MIC = 1 mg/L showed no inhibition zones around NOR and PF discs. In all resistant isolates, point mutations were detected in both genes. Serotype Ib was prevalent (88%). One PFGE type accounted for 84% of the FQ-resistant isolates and belonged to serotype Ib, sequence type 10. Conclusions: The prevalence of FQ resistance was 14.8% likely to be associated with dissemination of an ST10/serotype Ib clone. The unexpected high rate of resistance emphasizes the relevance for continuous surveillance of GBS epidemiology and antibiotic susceptibility.

Highlights

  • Streptococcus agalactiae or group B Streptococcus (GBS) is the leading cause of neonatal sepsis and meningitis and it has been recognized as an important pathogen in nonpregnant individuals, especially elderly people and those suffering from underlying medical disorders.[1,2]

  • A prospective observational study was designed to evaluate the prevalence and phenotypic and molecular features of FQ-resistant GBS isolates recovered from patients suffering from invasive disease caused by S. agalactiae

  • Resistant isolates proceeded from 13 different health care centers sited in 10 cities from 7 provinces across the country

Read more

Summary

Introduction

Streptococcus agalactiae or group B Streptococcus (GBS) is the leading cause of neonatal sepsis and meningitis and it has been recognized as an important pathogen in nonpregnant individuals, especially elderly people and those suffering from underlying medical disorders.[1,2]Penicillin (PEN) remains the first choice to treat GBS infections, strains with reduced susceptibility to this antibiotic have been recently described.[3,4] Alternative therapies are the use of macrolides and lincosamides; resistance to this class of antibiotics has emerged in the last decades.[5,6] Resistance to fluoroquinolone (FQ) in GBS was first described in Japan in 2003 and it became a growing problem.[7]. Resistance has been documented in Spain, United States of America, and Taiwan, but the highest levels of rates were found in Korea.[8,9,10,11] In Argentina, FQ resistance in GBS was first reported after a national surveillance study of noninvasive infections performed between 2005 and 2007; the prevalence of FQ resistance was 0.9%.12. Epidemiological studies of GBS resistance to fluoroquinolones (FQs) in Latin America are scarce. This study aimed to determine the local prevalence of FQ resistance in the frame of a national, prospective multicenter study of invasive GBS infections and to investigate mechanisms of resistance, serotype distribution, and clonal relationships among resistant isolates. One PFGE type accounted for 84% of the FQ-resistant isolates and belonged to serotype Ib, sequence type 10. The unexpected high rate of resistance emphasizes the relevance for continuous surveillance of GBS epidemiology and antibiotic susceptibility

Objectives
Methods
Results

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.