This article reports the spread of bla _KPC-2 in the Sao Paulo and Rio de Janeiro states, facilitated by globally spread K. pneumoniae clonal complex 258 (CC258) clones (ST258, ST11, and ST437) and a diversity of plasmids (IncFII, IncN, and IncL/M, two untypeable plasmids carrying Tn 4401 a or Tn 4401 b) successfully disseminated among species of the Enterobacteriaceae ( Enterobacter cloacae , Serratia marcescens , and Citrobacter freundii ). It also constitutes the first description of sequence type 258 (ST258) in Brazil, which was associated with a nosocomial hospital outbreak in Ribeirao Preto city.

In this study, we report the early expansion, evolution, and characterization of a multiresistant Klebsiella pneumoniae clone that was isolated with increasing frequency from inpatients in a tertiary-care university hospital in Brazil. Seven carbapenem- and quinolone-resistant and polymyxin B-susceptible or -resistant K. pneumoniae isolates isolated between December 2012 and February 2013 were investigated. Beta-lactamase- and plasmid-mediated quinolone resistance (PMQR)-encoding genes and the genetic environment were investigated using PCR, sequencing, and restriction fragment length polymorphism (RFLP). Clonal relatedness was established using XbaI–pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and phylogenetic group characterization. Plasmid analyses included PCR-based replicon typing (PBRT) and hybridization of the S1 -PFGE product, plasmid MLST, and conjugation experiments. Virulence potential was assessed by PCR by searching for 10 virulence factor-encoding genes ( ureA , fimH , kfuBC , uge , wabG , magA , mrkD , allS , rmpA , and cf29a ) and by phenotypic tests to analyze the hypermucoviscous phenotype. The genetic context of a multidrug-resistant and extensively drug-resistant K. pneumoniae ST11-KpI clone harboring IncFIIk-Tn 4401a-bla _KPC-2 , qnrS1 , and bla _CTX-M-2 was found. Moreover, three isolates displayed high resistance to polymyxin B (MICs = 32, 32, and 128 mg/liter) as well as mucous and hypermucoviscous phenotypes. These bacteria also harbored ureA , fimH , uge , wabG , and mrkD , which code for virulence factors associated with binding, biofilm formation, and the ability to colonize and escape from phagocytosis. Our study describes the association of important coresistance and virulence factors in the K. pneumoniae ST11 international high-risk clone, which makes this pathogen successful at infections and points to the quick expansion and evolution of this multiresistant and virulent clone, leading to a pandrug-resistant phenotype and persistent bacteria in a Brazilian hospital.

The aim of this study was to determine the spread of plasmid-mediated quinolone resistance determinants [qnr-like, aac(6′)-Ib-cr and qepA genes] among nalidixic acid-resistant enterobacterial strains isolated from outpatients from Southeast Brazil, their transferability and the genetic structures associated with the qnr genes. The qnrA, qnrB and qnrS genes were screened by a multiplex PCR-based technique from 257 non-repetitive nalidixic acid-resistant enterobacterial isolates collected from January 2000 to May 2005. Conjugation experiments were performed to determine whether the qnr-carrying plasmids were self-transferable. Genetic structures surrounding the qnr genes were analysed by PCR and cloning. The aac(6′)-Ib-cr and qepA genes were screened among qnr-positive strains. Six qnrB-like-positive isolates (2.3%) were detected, whereas no qnrA- or qnrS-positive isolates were detected. Three Escherichia coli and two Klebsiella pneumoniae isolates harboured a qnrB2 gene and a single Citrobacter freundii isolate had the qnrB8 gene. One qnrB2-positive isolate also had the extended-spectrum β-lactamase bla_CTX-M-2 gene. All these isolates also possessed chromosomal substitutions in gyrase- and topoisomerase-encoding genes, explaining their high-level resistance to quinolones. This study constitutes the first epidemiological survey of the three known Qnr determinants among Brazilian isolates and shows their low prevalence in that country, with the qnrB2 gene being mostly identified.

Reduced susceptibility or resistance to vancomycin has been reported among clinical isolates of staphylococci in previous studies. In the present study we report on the isolation of four vancomycin-resistant staphylococcal strains from healthy carriers inside and outside the hospital environment. These carriers did not receive treatment with any antibiotic. All coagulase-negative staphylococcal strains showed variable levels of resistance to several antimicrobial agents, including oxacillin, and unstable resistance to vancomycin, with decreased vancomycin MICs (<4 mg/liter) after 10 days of passage in a nonselective medium. However, exposure of these revertants to vancomycin selected staphylococcal strains resistant to vancomycin at very high frequencies (10 ⁻² and 10 ⁻³ ). The vancomycin resistance in these staphylococcal strains was not mediated by the van gene. The cell wall of the staphylococcal strains studied became thickest after culture in medium containing vancomycin, and the differences in cell wall thickness were statistically significant ( P < 0.001). Thus, the thickening of the cell wall in these staphylococcal strains may be an important contributor to vancomycin resistance.