The prevalence of hVISA was considerably high in central-southern China. Simultaneous carriage of multiple virulence genes was common in S. aureus isolates; the virulence genes were more diverse and frequent among MSSA isolates than among MRSA isolates. Furthermore, the distribution of some virulence genes was correlated with the different S. aureus CCs.

BackgroundThe spread of resistance to carbapenems among Enterobacteriaceae has become a major public health problem in recent years. In this study, we describe an outbreak of Klebsiella pneumoniae in the neonatal ward. First, we aimed to study the drug resistance, genetic relatedness, and transmission mechanism of carbapenem-resistant K. pneumoniae; second, we implemented infection control measures to contain the outbreak.MethodsWe investigated 27 non-repetitive strains isolated from neonates and five strains cultured from around the neonatal ward. Polymerase chain reaction (PCR), the agar dilution method, and multilocus sequence typing (MLST) were used to analyze the resistance gene(s), antimicrobial susceptibility, and homology, respectively. Health-care personnel education, hand hygiene, outer gown changing, and infected patient isolation were strictly enforced.ResultsOur antimicrobial susceptibility results show that all strains were multidrug-resistant. MLST and PCR results revealed that, in this study, all of the KPC-2-producing strains are Sequence Type (ST) 11 (ST11) (n = 22) and all of the NDM-1-producing strains are ST20 (n = 4) or ST888 (n = 1). The environmental strains were identified as KPC-2-positive K. pneumoniae ST11 (n = 3) and NDM-1-positive K. pneumoniae ST20 (n = 2). The percentages of isolates with the extended-spectrum-β-lactamases CTX-M-15, blaCTX-M-14, blaTEM-1 were 9.4, 84.3, and 68.8 %, respectively. AmpC β-lactamase genes were not detected in our isolates.ConclusionsKPC-2-positive K. pneumoniae ST11 and NDM-1-positive K. pneumoniae ST20 were associated with this outbreak. The identification of these isolates in samples from radiant warmers and nurses suggests that hospital cross-transmission played a role in this outbreak. Active infection control measures were effective for controlling this multidrug-resistant K. pneumoniae outbreak.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-016-1870-y) contains supplementary material, which is available to authorized users.

BackgroundAcute diarrhea is a leading cause of morbidity and mortality in children, particularly in those under the age of 5 years. Rotavirus is recognized as the leading cause of acute diarrhea in children, however, the contribution of bacterial pathogens as causative agents varies throughout the world. Here we report a hospital-based prospective study to analyze the characteristics of bacterial pathogens associated with acute diarrhea in children under 5 years of age.MethodsStool samples were collected from 508 patients with acute diarrhea under 5 years of age who presented at our hospital. Nine pathogens were isolated and identified by culturing, serology or PCR, these included Salmonella spp., Shigella spp., Vibrio cholerae, diarrheagenic Escherichia coli (DEC), Aeromonas spp., Plesiomonas spp., Vibrio parahaemolyticus, Campylobacter spp. and Yersinia enterocolitica. Antimicrobial sensitivity tests of these pathogens were conducted. The most commonly detected pathogen, Salmonella spp., was further investigated by PCR and sequencing of antibiotic resistance-related genes.ResultsPathogens were identified in 20.1 % of the 508 samples. The most commonly detected pathogens were Salmonella spp. (8.5 %), followed by DEC (4.7 %), Campylobacter jejuni (3.0 %) and Aeromonas spp. (2.0 %). The resistance rates to ampicillin and tetracycline in Salmonella spp. were >60 %, but were <30 % to cephalosporins and quinolones. More than 50 % of DEC strains displayed resistance to ampicillin, cefotaxime and tetracycline, and 60 % of C. jejuni strains were resistant to ciprofloxacin but highly sensitive to the other antibiotics. Among 12 cephalosporin-resistant Salmonella isolates, TEM-1 and CTX-M-14 determinants were present in two (16.7 %) isolates. PCR screening for plasmid-mediated quinolone resistance genes revealed gyrA mutations in one of three highly quinolone resistant isolates.ConclusionsSalmonella spp., DEC, Campylobacter spp. and Aeromonas spp. were the most commonly detected bacterial pathogens in children under the age of 5 years with acute diarrhea. Our findings indicate that ampicillin and tetracycline are not suitable as first line therapeutic drugs against Salmonella spp. Resistance to third generation cephalosporins and quinolones was also detected. TEM-1 and CTX-M-14 genetic determinants, and gyrA mutations, were the major mechanisms associated with high levels of cephalosporin and quinolone resistance, respectively, in Salmonella isolates.