Rapid detection of porins by matrix-assisted laser desorption/ionization-time of flight mass spectrometry.

The rapid and cost-efficient determination of carbapenem resistance is an important prerequisite for the choice of an adequate antibiotic therapy. A MALDI-TOF MS-based assay was set up to detect porins in the current study. A loss of the components of porin alone such as OmpK35/OmpK36 or together with the production of carbapenemases will augment the carbapenem resistance.

Dissemination of the same cfr-carrying plasmid among methicillin-resistant Staphylococcus aureus and coagulase-negative staphylococcal isolates in China.

Six cfr-harboring methicillin-resistant Staphylococcus aureus (MRSA) isolates, which belonged to the same clone of sequence type 5 (ST5)-staphylococcal cassette chromosome mec element II (SCCmec II)-spa t311, were investigated in this study. Complete sequencing of a cfr-carrying plasmid, pLRSA417, revealed an 8,487-bp fragment containing a Tn4001-like transposon, cfr, orf1, and ISEnfa4. This segment, first identified in an animal plasmid, pSS-01, was observed in several plasmids from clinical coagulase-negative staphylococci in China, suggesting that the cfr gene, which might originate from livestock, was located in the same mobile element and disseminated among different clinical staphylococcal species.

Emergence of KPC-2-producing Pseudomonas aeruginosa sequence type 463 isolates in Hangzhou, China.

Thirty-nine Klebsiella pneumoniae carbapenemase (KPC)-producing Pseudomonas aeruginosa isolates, all exhibiting high-level resistance to carbapenems and other β-lactam antibiotics, were isolated in Hangzhou, China. Molecular epidemiology analysis indicated the presence of two dominant clones, namely, clones A and B, both of which belong to sequence type 463 (ST463). A genetic environment analysis demonstrated that both clones harbor an ISKpn8 transposase, bla(KPC-2), and an ISKpn6-like transposase.

Emergence of Escherichia coli sequence type 131 isolates producing KPC-2 carbapenemase in China.

Twenty-two KPC-2-producing Escherichia coli isolates were obtained from three hospitals in Hangzhou, China, from 2007 to 2011. One isolate, with OmpC porin deficiency, exhibited high-level carbapenem resistance. Pulsed-field gel electrophoresis showed that few isolates were indistinguishable or closely related.

Molecular typing of CTX-M-producing escherichia coli isolates from environmental water, swine feces, specimens from healthy humans, and human patients.

CTX-M-producing Escherichia coli is the predominant type of extended-spectrum β-lactamase (ESBL)-producing E. coli worldwide. In this study, molecular typing was conducted for 139 CTX-M-producing E.

Linezolid-resistant clinical isolates of meticillin-resistant coagulase-negative staphylococci and Enterococcus faecium from China.

Seventeen meticillin-resistant coagulase-negative staphylococci (MRCoNS), including ten Staphylococcus capitis, four Staphylococcus cohnii, two Staphylococcus haemolyticus and one Staphylococcus sciuri, and an Enterococcus faecium isolate with various levels of linezolid resistance were isolated from intensive care units in a Chinese hospital. PFGE indicated that the four S. cohnii isolates belonged to a clonal strain, and that nine of the S.

High prevalence of qnr and aac(6')-Ib-cr genes in both water-borne environmental bacteria and clinical isolates of Citrobacter freundii in China.

We investigated the prevalence of qnr and aac(6')-Ib-cr genes in water-borne environmental bacteria and in clinical isolates of Enterobacteriaceae, as well as the subtypes of qnr. Environmental bacteria were isolated from surface water samples obtained from 10 different locations in Hangzhou City, and clinical isolates of Citrobacter freundii were isolated from several hospitals in four cities in China. qnrA, qnrB, qnrS, and aac(6')-Ib-cr genes were screened using PCR, and the genotypes were analyzed by DNA sequencing.

Detection of KPC-2 and qnrS1 in clinical isolates of Morganella morganii from China.

Seven carbapenem-nonsusceptible Morganella morganii isolates, which have similar antibiotic susceptibility profiles, were isolated over a 5-month period. MICs of imipenem, meropenem, and ertapenem were 8, 1, and 0.25 to 0.

Emergence of Proteus mirabilis harboring blaKPC-2 and qnrD in a Chinese Hospital.

Nineteen carbapenem-nonsusceptible Proteus mirabilis isolates were recovered from intensive care units in the Second Affiliated Hospital of Zhejiang University during a 3-month period. The isolates showed a high level of resistance against ciprofloxacin, in addition to their resistance against the carbapenems. Pulsed-field gel electrophoresis (PFGE) analysis showed that these isolates belonged to three clonal strains.

Genotypic characterization and in vitro activities of tigecycline and polymyxin B for members of the Enterobacteriaceae with decreased susceptibility to carbapenems.

Carbapenem resistance in members of the Enterobacteriaceae is increasing. To evaluate the effects of tigecycline and polymyxin B against carbapenem-non-susceptible pathogens, 89 representative clinical carbapenem-non-susceptible Enterobacteriaceae isolates were recovered from seven hospitals from four cities in China during 2006-2009: 30 Serratia marcescens, 35 Klebsiella pneumoniae, seven Enterobacter cloacae, six Enterobacter aerogenes, five Escherichia coli, four Citrobacter freundii and two Klebsiella oxytoca isolates. Twenty-eight S.

Outbreak of Klebsiella pneumoniae carbapenemase 2-producing K. pneumoniae with high qnr prevalence in a Chinese hospital.

Forty carbapenem-resistant Klebsiella pneumoniae isolates were recovered from 28 patients from various sites in an intensive care unit in Zhejiang Provincial People's Hospital, China, over a 6 month period. PFGE analysis indicated that the 40 strains were all closely related. The MICs of carbapenems varied from 16 to >256 µg ml⁻¹.

Serotypes and extended-spectrum β-lactamase types of clinical isolates of Shigella spp. from the Zhejiang province of China.

To understand the distribution of the serotypes of Shigella spp. and to investigate the drug-resistant genes of extended-spectrum β-lactamases (ESBLs) in Shigella in Zhejiang province, we have collected clinically isolated Shigella isolates from 2 hospitals in Zhejiang province during August to December of 2006. There are 11 Shigella flexneri and 13 Shigella sonnei isolates, respectively.

Combination of IMP-4 metallo-beta-lactamase production and porin deficiency causes carbapenem resistance in a Klebsiella oxytoca clinical isolate.

This study shows for the first time the mechanism of carbapenem resistance of a Klebsiella oxytoca clinical isolate ZC101 recovered from a Zhejiang University Hospital in Hangzhou, China. MIC values of imipenem, meropenem, and ertapenem for K. oxytoca ZC101 were 16, 16, and 128 microg/mL, respectively.

Reduced susceptibility to carbapenems in Klebsiella pneumoniae clinical isolates associated with plasmid-mediated beta-lactamase production and OmpK36 porin deficiency.

Two carbapenem-non-susceptible Klebsiella pneumoniae isolates, Z2554 and Z2110, were collected from a hospital in China and analysed by PFGE. K. pneumoniae Z2554 and Z2110 were genetically unrelated and showed resistance to ertapenem, and reduced susceptibility to imipenem and meropenem.

Detection of plasmid-mediated IMP-1 metallo-beta-lactamase and quinolone resistance determinants in an ertapenem-resistant Enterobacter cloacae isolate.

Objective: To investigate the mechanism of carbapenem resistance and the occurrence of plasmid-mediated quinolone resistance determinants qnr and aac(6')-Ib-cr in a clinical isolate of Enterobacter cloacae.

Methods: An ertapenem-resistant E. cloacae ZY106, which was isolated from liquor puris of a female gastric cancer patient in a Chinese hospital, was investigated.

[Detection of plasmid-mediated carbapenem-hydrolyzing beta-lactamase KPC-2 in a strain of carbapenem-resistant Enterobacter cloacae].

Objective: To investigate the mechanism of carbapenem resistance in Enterobacter cloacae.

Methods: A carbapenem-resistant strain of E. cloacae (strain ZY1465) was isolated.

Emergence of Serratia marcescens, Klebsiella pneumoniae, and Escherichia coli Isolates possessing the plasmid-mediated carbapenem-hydrolyzing beta-lactamase KPC-2 in intensive care units of a Chinese hospital.

Twenty-one Serratia marcescens, ten Klebsiella pneumoniae, and one Escherichia coli isolate with carbapenem resistance or reduced carbapenem susceptibility were recovered from intensive care units (ICUs) in our hospital. Enterobacterial repetitive intergenic consensus-PCR and pulsed-field gel electrophoresis demonstrated that all the S. marcescens isolates belonged to a clonal strain and the 10 K.

High-level carbapenem resistance in a Citrobacter freundii clinical isolate is due to a combination of KPC-2 production and decreased porin expression.

An imipenem-resistant isolate of Citrobacter freundii ZJ163 (MIC 256 microg ml(-1)) isolated from a Chinese hospital was investigated. The C. freundii ZJ163 isolate exhibited high-level resistance to carbapenems, penicillins, cephalosporins, cefoxitin, aztreonam, quinolones and aminoglycosides.