MRSA from Chinese pigs and farm workers (ST9) differed from the European pig-associated clone (ST398) with regard to clonal type, SCCmec content and resistance profile.

Based on these results, fluoroquinolones should not be used to treat the invasive Salmonella Typhimurium infections in this local community. The monitoring programme should stay vigilant for ceftriaxone-resistant S. enterica isolates with reduced fluoroquinolone susceptibility.

ESBL-producing or fluoroquinolone-resistant Shigella is no longer an unusual phenomenon in the local community. The monitoring programme in China should stay vigilant to the dissemination of these isolates and the health agencies must take appropriate measures to restrict the abuse of antimicrobials, especially in the community.

Background: The categories of recognized transferable quinolone resistance determinants have been increasing sharply. The rapid horizontal transfer of these quinolone resistance genes has caused concern since they bring new dissemination possibilities for quinolone resistance.Methods: In total, 579 clinical Escherichia coli isolates were subjected to antimicrobial susceptibility testing, screening for qnr alleles, qepA and aac-(6 0 )-Ib-cr by PCR amplification and DNA sequence analysis. Isolates containing transferable quinolone resistance determinants were further characterized by mutation analysis in the quinolone resistance determining regions (QRDRs) of GyrA and ParC, phylogenetic typing and PFGE to determine their genetic relatedness.Results: After PCR screening and sequence analysis, transferable quinolone resistance determinants were identified in 74 of 579 E. coli isolates (12.8%). The antimicrobial resistance profiles and phylogenetic groups differed between isolates containing different categories of transferable quinolone resistance determinant. Most of the isolates containing qepA alone were highly resistant to ciprofloxacin (MIC 512 mg/L) and belonged to phylogenetic group D (22/25), while most of the isolates containing aac-(6 0 )-Ib-cr alone belonged to phylogenetic group A (17/35) or D (16/35). Of 74 E. coli isolates containing transferable quinolone resistance determinants, 69 PFGE patterns and 19 clusters were identified. Conclusions:The great genetic variation of E. coli hosts containing transferable quinolone resistance determinants demonstrated the high transmission capacity of these mechanisms. It is urgent to characterize and block their transmission routes in order that the utility of quinolones is preserved.

We characterized 44 Salmonella enterica serotype Typhimurium isolates from Tongji Hospital outpatients in Wuhan, China, May 2002–October 2005. All 31 ciprofloxacin-resistant isolates were also resistant to > 8 other antimicrobial drugs and carried > 2 mutations in GyrA and 1 mutation in ParC. Class 1 integrons were identified in 37 isolates.