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Zong Z.,University of Sichuan | Zong Z.,State Key Laboratory of Biotherapy | Lu X.,University of Sichuan
PLoS ONE | Year: 2010

Background: Many SCCmec elements of coagulase-negative staphylococci (CoNS) could not be typed using multiplex PCR. Such a 'non-typable' SCCmec was encountered in a Staphylococcus cohnii isolate. Methodology/Principal Findings: The SCCmec type of methicillin-resistant S. cohnii clinical isolate WC28 could not be assigned using multiplex PCR. Newly-designed primers were used to amplify ccrA and ccrB genes. The whole SCCmec was obtained by three overlapping long-range PCR, targeting regions from left-hand inverted repeat (IRL) to ccrA/B, from ccrA/B to mecA and from mecA to orfX. The region abutting IRL was identified using inverse PCR with self-ligated enzyme-restricted WC28 fragments as the template. WC28 SCCmec had a class A mec gene complex (mecI-mecR1-mecA). The ccrA and ccrB genes were closest (89.7% identity) to ccrASHP of Staphylococcus haemolyticus strain H9 and to ccrB3 (90% identity) of Staphylococcus pseudintermedius strain KM241, respectively. Two new genes potentially encoding AAA-type ATPase were found in J1 region and a ΨTn554 transposon was present in J2 region, while J3 region was the same as many SCCmec of Staphylococcus aureus. WC28 SCCmec abutted an incomplete SCC element with a novel allotype of ccrC, which was closest (82% identity) to ccrC1 allele 9 in Staphylococcus saprophyticus strain ATCC 15305. Only two direct target repeat sequences, one close to the 39-end of orfX and the other abutting the left end of WC28 SCCmec, could be detected. Conclusions/Significance: A new 35-kb SCCmec was characterized in a S. cohnii isolate, carrying a class A mec gene complex, new variants of ccrA5 and ccrB3 and two novel genes in the J1 region. This element is flanked by 8-bp perfect inverted repeats and is similar to type III SCCmec in S. aureus and a SCCmec in S. pseudintermedius but with different J1 and J3 regions. WC28 SCCmec was arranged in tandem with an additional SCC element with ccrC, SCC WC28, but the two elements might have integrated independently rather than constituted a composite. This study adds new evidence of the diversity of SCCmec in CoNS and highlights the need for characterizing the 'non-typable' SCCmec to reveal the gene pool associated with mecA. © 2010 Zong, Lü.

Zong Z.,University of Sichuan | Zong Z.,State Key Laboratory of Biotherapy | Peng C.,University of Sichuan | Lu X.,University of Sichuan
PLoS ONE | Year: 2011

Background: Methicillin-resistant coagulase-negative staphylococci (MR-CoNS) are opportunistic pathogens and serve as a large reservoir of staphylococcal cassette chromosome mec (SCCmec). Characterization of SCCmec in MR-CoNS can generate useful information on the mobilization and evolution of this element. Methodology/Principal Findings: Non-repetitive MR-CoNS clinical isolates (n = 84; 39 S. epidermidis, 19 S. haemolyticus, 9 S. hominis, 6 S. capitis, 4 S. warneri, 2 S. cohnii, 2 S. saprophyticus, 1 S. kloosii, 1 S. simulans and 1 S. massiliensis) were collected. All isolates could grow on plates with 4 mg/L cefoxitin and all had mecA as detected by PCR. Strain typing using RAPD and ERIC-PCR revealed that almost all isolates were of different strains. SCCmec typing was performed using multiplex PCR published previously. For isolates in which SCCmec could not be typed, the mec complex classes were determined by additional PCR and the ccr genes were amplified with published or newly-designed primers and then sequenced. SCCmec types were assigned for 63 isolates by multiplex PCR and were assigned for 14 other isolates by PCR targeting mec and ccr. Among 77 isolates with determined SCCmec types, 54 had a single type, including type III (n = 19), IV (n = 14), V (n = 10), II (n = 2), I (n = 1), VIII (n = 1) and five unnamed types (n = 7), while 23 isolates had two types, III+V (n = 12), II+V (n = 8), II+IV (n = 2) or IV+V (n = 1). The five unnamed types were assigned UT1 (class A mec, ccrA1/ccrB4), UT2 (class C1 mec, ccrA4/ccrB4), UT3 (class A mec, ccrA5/ccrB3), UT4 (class C2 mec, ccrA2/ccrB2 plus ccrC1) and UT5 (class A mec, ccrA1/ccrB1 plus ccrC1). Conclusions/Significance: SCCmec types III, IV and V were prevalent in MR-CoNS and many isolates could harbor more than one type. Several new types of SCCmec were identified, highlighting the great genetic diversity and the need of developing classification schemes for SCCmec in MR-CoNS. © 2011 Zong et al.

Zong Z.,University of Sichuan | Zong Z.,State Key Laboratory of Biotherapy
Antonie van Leeuwenhoek, International Journal of General and Molecular Microbiology | Year: 2012

Staphylococcus massiliensis is a newly-recognized species but its ecological niche and its role in infection remained unclear. Clinical isolate WCG21 recovered from a wound sample was initially identified as Staphylococcus simulans by the WalkAway automated system but was subsequently identified as S. massiliensis by partially sequencing the 16S rRNA and dnaJ genes. Strain WCG21 was probably a contaminant rather than a pathogen. The 16S rRNA gene sequences of several bacterial clones from human skin were also identical or near identical to that of S. massiliensis, suggesting that this species is part of human skin microflora. Although strain WCG21 was susceptible to a wide range of antimicrobials, it harbored a type V staphylococcal cassette chromosome mec. © 2011 Springer Science+Business Media B.V.

Yang P.,University of Sichuan | Yang P.,State Key Laboratory of Biotherapy | Xie B.Y.,University of Sichuan | Feng P.,University of Sichuan | And 2 more authors.
Antimicrobial Agents and Chemotherapy | Year: 2014

blaNDM-5was found in Escherichia coli strain 0215 from a Chinese patient without travel history. Genomic sequencing and conjugation experiments were performed. Strain 0215 belonged to sequence type 167 (ST167) and had other resistance determinants, including blaTEM-135, blaCTX-M-14, and aac(6=)-Ib. blaNDM-5was carried by a 47-kb self-transmissible IncX3 plasmid and was in a complex genetic context similar to that of blaNDM-1 on IncX3 plasmids. IncX3 plasmids might have emerged as a common vehicle mediating the spread of blaNDM. © 2014 American Society for Microbiology. All Rights Reserved.

Wang X.,University of Sichuan | Wang X.,State Key Laboratory of Biotherapy | Yu R.,State Key Laboratory of Biotherapy | Lu X.,University of Sichuan | And 2 more authors.
Diagnostic Microbiology and Infectious Disease | Year: 2013

Among 82 clinical isolates of the Acinetobacter calcoaceticus-baumannii complex recovered in 13 hospitals of Sichuan, China, in 2011, 13 were Acinetobacter pittii and 2 were Acinetobacter nosocomialis. Multilocus sequence typing revealed a novel sequence type (ST) of A. nosocomialis and 7 novel STs of A. pittii. Most isolates were hospital-acquired and colonized in the respiratory tract, while 6 cases with pneumonia due to A. pittii were identified. This study provided a snapshot of the local incidence of A. pittii and A. nosocomialis. © 2013 Elsevier Inc.

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