First Characterization of Fluoroquinolone Resistance in Streptococcus suis

Abstract

We have identified and sequenced the genes encoding the quinolone-resistance determining region (QRDR) of ParC and GyrA in fluoroquinolone-susceptible and -resistant Streptococcus suis clinical isolates. Resistance is the consequence of single point mutations in the QRDRs of ParC and GyrA and is not due to clonal spread of resistant strains or horizontal gene transfer with other bacteria.

Overexpression of an ABC transporter and mutations of GyrA, GyrB, and ParC in contributing to high-level ciprofloxacin resistance in Streptococcus suis type 2

“…Only one strain had a single mutation in GyrB without mutations in GyrA, ParC, or ParE. The resistance mutations in GyrA and ParC in our strains occurred at the expected hot spots (GyrA-S81Y; ParC-S79Y), which are generally similar to those reported by Escudero et al (13) and those in other Gram-positive bacteria, such as S. aureus, S. pneumoniae, S. pyogenes, and E. faecium (18,(24)(25)(26)(27). It has already been demonstrated that QRDR alterations in GyrB and ParE are associated with fl uoroquinolone resistance in Gram-positive bacteria such as S. aureus, S. pneumoniae, and E. faecium (25,27,28), but this has not been reported in S. suis.…”

“…Fluorquinolone resistance in S. suis occurs by two mechanisms including mutations in the QRDRs of the gyrA and parC genes and the mediation of FQ effl ux by the SatAB pump (13,15). Based on existing knowledge of FQ resistance and the related literature, the main purpose of our study was to explore the underlying molecular mechanism of FQ resistance after in vitro induction of fl uoroquinolones in S. suis, due to the highly pathogenic nature and zoonotic importance.…”

“…Only two studies have reported resistant mechanisms. One is point mutations in quinolone resistance-determining regions (QRDRs) of the gyrA subunit of the DNA gyrase and parC subunit of DNA topoisomerase IV, and another reason of developing resistance to fluoroquinolones is decreased accumulation of these FQ agents in bacterial cells mediated by SatAB (13,15).…”

“…However, treatment failure in streptococcal infections is reported worldwide due to the emergence of strains resistant to FQs and other antibiotics in recent years. Such multidrug resistant streptococcal strains have become a universal problem and have severe consequences for pigs and for human health (11)(12)(13)(14)(15).…”

Haemophilus influenzae Clinical Isolates with Plasmid pB1000 Bearing bla ROB-1 : Fitness Cost and Interspecies Dissemination

“…It is known that animals can play important roles as reservoirs and sources of antimicrobial-resistant pathogens (20,21), posing an important concern for public health. Not only the zoonotic circulation of resistant bacteria (6,20,21) but also the spread of antimicrobial resistance determinants between animal and human pathogens has been widely described (1,16). Here we characterized four high-level cefaclor-resistant H. influenzae human clinical isolates recovered between 2000 and 2009 in Spain.…”