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1.
Background
Simultaneous resistance to aminoglycosides and fluoroquinolones in carbapeneme non-susceptible (CNS) isolates will inevitably create problems. The present study was performed to characterize the prevalence of the plasmid-mediated quinolone resistance determinants (QRDs) and aminoglycoside resistance determinants (ARDs) among the CNS Enterobacter cloacae (E. cloacae) isolates in a Chinese teaching hospital, and to acquire their molecular epidemiological characteristics.Methods
The β-lactamases genes (including class A carbapenemase genes blaKPC and blaSME, metallo-β-lactamase genes (MBLs) blaIMP, blaVIM and blaNDM, and extended spectrum β-lactamases (ESBLs),blaCTX-M, blaTEM and blaSHV), QRDs (including qnrA, qnrB, qnrS and aac(6′)-Ib-cr) and ARDs (including aac(6′)-Ib, armA and rmtB) of these 35 isolates were determined by PCR and sequenced bidirectionally. The clonal relatedness was investigated by pulsed-field gel electrophoresis (PFGE).Results
Of the 35 isolates, 9 (25.7%) harbored a carbapenemase gene; 23 (65.7%) carried ESBLs; 24 (68.6%) were QRD positive; and 27 (77.1%) were ARD positive. Among the 5 blaIMP-8 positive strains, 4 (80%) contained both ESBL and QRD genes, and all the 5 (100%) harbored ARD genes. Of the 23 ESBLs positive isolates, 6 (26.1%) were carbapenemase positive, 14 (60.9%) were QRD positive, and 18 (78.3%) were ARD positive. PFGE revealed genetic diversity among the 35 isolates, indicating that the high prevalence of CNS E. cloacae isolates was not caused by clonal dissemination.Conclusion
QRD and ARD genes were highly prevalent among the CNS E. cloacae isolates. Multiple resistant genes were co-expressed in the same isolates. The CNS E. cloacae isolate co-expressing blaNDM-1, blaIMP-26, qnrA1 and qnrS1 was first reported. 相似文献2.
Sheng-Kang Chiu Tsu-Lan Wu Yin-Ching Chuang Jung-Chung Lin Chang-Phone Fung Po-Liang Lu Jann-Tay Wang Lih-Shinn Wang L. Kristopher Siu Kuo-Ming Yeh 《PloS one》2013,8(7)
Objectives
The global spread and increasing incidence of carbapenem non-susceptible Klebsiella pneumoniae (CnSKP) has made its treatment difficult, increasing the mortality. To establish nationwide data on CnSKP spread and carbapenem-resistance mechanisms, we conducted a national surveillance study in Taiwanese hospitals.Methods
We collected 100 and 247 CnSKP isolates in 2010 and 2012, respectively. The tests performed included antibiotic susceptibility tests; detection of carbapenemase, extended-spectrum β-lactamases (ESBL), and AmpC β-lactamases genes; outer membrane porin profiles; and genetic relationship with pulsed-field gel electrophoresis and multilocus sequence type.Results
The resistance rate of CnSKP isolates to cefazolin, cefotaxime, cefoxitin, ceftazidime, and ciprofloxacin was over 90%. Susceptibility rate to tigecycline and colistin in 2010 was 91.0% and 83.0%, respectively; in 2012, it was 91.9% and 87.9%, respectively. In 2010, carbapenemase genes were detected in only 6.0% of isolates (4 bla IMP-8 and 2 bla VIM-1). In 2012, carbapenemase genes were detected in 22.3% of isolates (41 bla KPC-2, 7 bla VIM-1, 6 bla IMP-8, and 1 bla NDM-1). More than 95% of isolates exhibited either OmpK35 or OmpK36 porin loss or both. Impermeability due to porin mutation coupled with AmpC β-lactamases or ESBLs were major carbapenem-resistance mechanisms. Among 41 KPC-2-producing K. pneumoniae isolates, all were ST11 with 1 major pulsotype.Conclusions
In 2010 and 2012, the major mechanisms of CnSKP in Taiwan were the concomitance of AmpC with OmpK35/36 loss. KPC-2-KP dissemination with the same ST11 were observed in 2012. The emergence and rapid spread of KPC-2-KP is becoming an endemic problem in Taiwan. The identification of NDM-1 K. pneumoniae case is alarming. 相似文献3.
Background
The prevalence of carbapenem-resistant Acinetobacter baumannii in hospitals has been increasing worldwide. This study aims to investigate the carbapenemase genes and the clonal relatedness among A. baumannii clinical isolates in a Chinese hospital.Methods
Carbapenemase genes and the upstream locations of insertion sequences were detected by polymerase chain reaction (PCR), and the clonal relatedness of isolates was determined by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing.Results
A total of 231 nonduplicate carbapenemase gene-harboring A. baumannii clinical isolates recovered from Shenzhen People’s Hospital, were investigated between 2002 and 2009. bla OXA-23-like, bla OXA-58-like, bla OXA-40-like, and ISAba1-bla OXA-51-like were identified in 119, 107, 1, and 4 isolates, respectively. IS1008-ΔISAba3, ISAba3, and ISAba1 were detected upstream of the bla OXA-58-like gene in 69, 35, and 3 isolates, respectively. All bla OXA-23-like genes but one had an upstream insertion of ISAba1. bla OXA-58-like was the most common carbapenemase gene in A.baumannii before 2008, thereafter bla OXA-23-like became rapidly prevalent and replaced bla OXA-58-like in 2009. The majority of bla OXA-58-like-carrying isolates showed lower level of resistance to imipenem and meropenem (minimum inhibitory concentrations (MICs), 1 μg/ml to 16 μg/ml), compared with the majority of bla OXA-23-like-carrying isolates (MICs, 16 μg/ml to 64 μg/ml for both imipenem and meropenem). All 231 bla OXA carbapenemase gene-harboring isolates belonged to 14 PFGE types (A–N), and three dominant clones A, J, and H accounted for 43.3%, 42.0%, and 8.2% of the tested isolates, respectively. Clone A (sequence type ST92/ST208) with bla OXA-58-like was the most prevalent before 2008. Clone H (ST229) with bla OXA-23-like became striking between 2007 and 2008. Clone J (ST381) with bla OXA-23-like rapidly spread and replaced clones A and H in 2009.Conclusion
This study is the first to reveal that the distinct bla OXA-23-like-carrying A. baumannii ST381 displaced the previously prevalent bla OXA-58-like-carrying A. baumannii ST92/ST208, resulting in the rapidly increasing resistance to carbapenems in A. baumannii in Shenzhen People’s Hospital in 2009. 相似文献4.
H. M. Abdallah E. A. Reuland B. B. Wintermans N. al Naiemi A. Koek A. M. Abdelwahab A. M. Ammar A. A. Mohamed C. M. J. E. Vandenbroucke-Grauls 《PloS one》2015,10(8)
Objectives
The aim of the present study was to determine the prevalence and to characterize extended-spectrum β-lactamases- and/or carbapenemases-producing Enterobacteriaceae among Enterobacteriaceae isolated from retail chicken meat in Zagazig, Egypt.Methods
One hundred and six Enterobacteriaceae isolates were collected from retail chicken meat samples purchased in Zagazig, Egypt in 2013. Species identification was done by MALDI-TOF MS. Screening for ESBL-E was performed by inoculation of isolates recovered from meat samples onto the EbSA (Cepheid Benelux, Apeldoorn, the Netherlands) selective screening agar. ESBL production was confirmed by combination disc diffusion test with clavulanic acid (Rosco, Taastrup, Denmark). Carbapenemases production was confirmed with double disk synergy tests. Resistance genes were characterized by PCR with specific primers for TEM, SHV, and CTX-M and carbapenemases (KPC, NDM, OXA-48, IMP and VIM). PCR products of CTX-M genes were purified and sequenced. Phylogenetic grouping of E. coli was performed by a PCR-based method.Results
Of these 106 isolates 69 (65.09%) were ESBL producers. Twelve (11.32%) of these isolates were also phenotypically class B carbapenemases producer. TEM genes were detected in 61 (57.55%) isolates. 49 (46.23%) isolates harbored CTX-M genes, and 25 (23.58%) carried genes of the SHV family. All CPE belonged to the NDM group. The predominant CTX-M sequence type was CTX-M-15 (89.80%). The majority (80%) of the ESBL-EC belonged to low virulence phylogroups A and B1.Conclusions
This is the first study from Egypt reporting high rates of ESBLs and carbapenemases (65.09% and 11.32%, respectively) in Enterobacteriaceae isolated from retail chicken meat. These results raise serious concerns about public health and food safety as retail meat could serve as a reservoir for these resistant bacteria which could be transferred to humans through the food chain. 相似文献5.
Angela H. A. M. van Hoek Leo Schouls Marga G. van Santen Alice Florijn Sabine C. de Greeff Engeline van Duijkeren 《PloS one》2015,10(6)
Objective
To investigate the molecular characteristics of extended-spectrum cephalosporin (ESC)-resistant Enterobacteriaceae collected during a cross-sectional study examining the prevalence and risk factors for faecal carriage of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae in humans living in areas with high or low broiler density.Methods
ESC-resistant Enterobacteriaceae were identified by combination disc-diffusion test. ESBL/AmpC/carbapenemase genes were analysed using PCR and sequencing. For E. coli, phylogenetic groups and MLST were determined. Plasmids were characterized by transformation and PCR-based replicon typing. Subtyping of plasmids was done by plasmid multilocus sequence typing.Results
175 ESC-resistant Enterobacteriaceae were cultured from 165/1,033 individuals. The isolates were Escherichia coli(n=65), Citrobacter freundii (n=52), Enterobacter cloacae (n=38), Morganella morganii (n=5), Enterobacter aerogenes (n=4), Klebsiella pneumoniae (n=3), Hafnia alvei (n=2), Shigella spp. (n=2), Citrobacter amalonaticus (n=1), Escherichia hermannii (n=1), Kluyvera cryocrescens (n=1), and Pantoea agglomerans (n=1). The following ESBL genes were recovered in 55 isolates originating from 49 of 1,033 (4.7 %) persons: bla CTX-M-1 (n=17), bla CTX-M-15 (n=16), bla CTX-M-14 (n=9), bla CTX-M-2 (n=3), bla CTX-M-3 (n=2), bla CTX-M-24 (n=2), bla CTX-M-27 (n=1), bla CTX-M-32 (n=1), bla SHV-12 (n=2), bla SHV-65 (n=1) and bla TEM-52 (n=1). Plasmidic AmpC (pAmpC) genes were discovered in 6 out of 1,033 (0.6 %) persons. One person carried two different E. coli isolates, one with bla CTX-M-1 and the other with bla CMY-2 and therefore the prevalence of persons carrying Enterobacteriaceae harboring ESBL and/or pAmpC genes was 5.2 %. In eight E. coli isolates the AmpC phenotype was caused by mutations in the AmpC promoter region. No carbapenemase genes were identified. A large variety of E. coli genotypes was found, ST131 and ST10 being most common.Conclusions
ESBL/pAmpC genes resembled those from patients in Dutch hospitals, indicating that healthy humans form a reservoir for transmission of these determinants to vulnerable people. The role of poultry in the transmission to humans in the community remains to be elucidated. 相似文献6.
Supriya Upadhyay Abbas Hussain Shweta Mishra Anand Prakash Maurya Amitabha Bhattacharjee Santa Ram Joshi 《PloS one》2015,10(9)
Background
The study investigated the presence of CTX-M-15 type extended spectrum beta-lactamases (ESBL), compared their genetic arrangements and plasmid types in gram negative isolates of hospital and food origin in north-east India. From September 2013 to April 2014, a total of 252 consecutive, non-duplicate clinical isolates and 88 gram negative food isolates were selected. Phenotypic and molecular characterization of ESBL genes was performed. Presence of integrons and gene cassettes were analyzed by integrase and 59 base-element PCR respectively. The molecular environments surrounding bla CTX-M and plasmid types were investigated by PCR and PCR-based replicon typing respectively. Transformation was carried out to assess plasmid transfer. Southern blotting was conducted to localize the bla CTX-M-15 genes. DNA fingerprinting was performed by ERIC-PCR.Results
Prevalence of ESBL was found to be 40.8% (103/252) in clinical and 31.8% (28/88) in food-borne isolates. Molecular characterization revealed the presence of 56.3% (58/103) and 53.5% (15/28) bla CTX-M-15 in clinical and food isolates respectively. Strains of clinical and food origin were non-clonal. Replicon typing revealed that IncI1 and IncFII plasmid were carrying bla CTX-M-15 in clinical and food isolates and were horizontally transferable. The ISEcp1 element was associated with bla CTX-M-15 in both clinical and food isolates.Conclusions
The simultaneous presence of resistance determinants in non-clonal isolates of two different groups thus suggests that the microbiota of common food products consumed may serve as a reservoir for some of the drug resistance genes prevalent in human pathogens. 相似文献7.
Background
The NDM-1 carbapenemase has been identified in 2008 in Enterobacteriaceae. Since then, several reports have emphasized its rapid dissemination throughout the world. The spread of NDM carbapenemases involve several bla NDM gene variants associated with various plasmids among several Gram negative species.Methodology
A multidrug-resistant E. coli isolate recovered from urine of a patient who had travelled to Burma has been characterized genetically and biochemically.Principal Findings
E. coli COU was resistant to all antibiotics tested except amikacin, tigecycline, fosfomycin, and chloramphenicol. Analysis of the antibiotic resistance traits identified a metallo-ß-lactamase, a novel NDM variant, NDM-7. It differs from NDM-4 by a single amino acid substitution sharing an identical extended spectrum profile towards carbapenems. The bla NDM-7 gene was located on an untypeable conjugative plasmid and associated with a close genetic background similar to those described among the bla NDM-1 genes. The isolate also harbours bla CTXM-15 and bla OXA-1 genes and belonged to ST167.Significance
This study highlights that spread of NDM producers correspond to spread of multiple bla NDM genes and clones and therefore will be difficult to control. 相似文献8.
Hattie E. Webb Marie Bugarel Henk C. den Bakker Kendra K. Nightingale Sophie A. Granier H. Morgan Scott Guy H. Loneragan 《PloS one》2016,11(1)
Objective
A study was conducted to recover carbapenem-resistant bacteria from the faeces of dairy cattle and identify the underlying genetic mechanisms associated with reduced phenotypic susceptibility to carbapenems.Methods
One hundred and fifty-nine faecal samples from dairy cattle were screened for carbapenem-resistant bacteria. Phenotypic screening was conducted on two media containing ertapenem. The isolates from the screening step were characterised via disk diffusion, Modified Hodge, and Carba NP assays. Carbapenem-resistant bacteria and carbapenemase-producing isolates were subjected to Gram staining and biochemical testing to include Gram-negative bacilli. Whole genome sequencing was performed on bacteria that exhibited either a carbapenemase-producing phenotype or were not susceptible to ertapenem and were presumptively Enterobacteriaceae.Results
Of 323 isolates collected from the screening media, 28 were selected for WGS; 21 of which were based on a carbapenemase-producing phenotype and 7 were presumptively Enterobacteriaceae and not susceptible to ertapenem. Based on analysis of WGS data, isolates included: 3 Escherichia coli harbouring blaCMY-2 and truncated ompF genes; 8 Aeromonas harbouring blacphA-like genes; 1 Acinetobacter baumannii harbouring a novel blaOXA gene (blaOXA-497); and 6 Pseudomonas with conserved domains of various carbapenemase-producing genes.Conclusions
Carbapenem resistant bacteria appear to be rare in cattle. Nonetheless, carbapenem-resistant bacteria were detected across various genera and were found to harbour a variety of mechanisms conferring reduced susceptibility. The development and dissemination of carbapenem-resistant bacteria in livestock would have grave implications for therapeutic treatment options in human medicine; thus, continued monitoring of carbapenem susceptibility among enteric bacteria of livestock is warranted. 相似文献9.
Richard Echodu Mark Sistrom Rosemary Bateta Grace Murilla Loyce Okedi Serap Aksoy Chineme Enyioha John Enyaru Elizabeth Opiyo Wendy Gibson Adalgisa Caccone 《PLoS neglected tropical diseases》2015,9(2)
Background
While Human African Trypanosomiasis (HAT) is in decline on the continent of Africa, the disease still remains a major health problem in Uganda. There are recurrent sporadic outbreaks in the traditionally endemic areas in south-east Uganda, and continued spread to new unaffected areas in central Uganda. We evaluated the evolutionary dynamics underpinning the origin of new foci and the impact of host species on parasite genetic diversity in Uganda. We genotyped 269 Trypanosoma brucei isolates collected from different regions in Uganda and southwestern Kenya at 17 microsatellite loci, and checked for the presence of the SRA gene that confers human infectivity to T. b. rhodesiense.Results
Both Bayesian clustering methods and Discriminant Analysis of Principal Components partition Trypanosoma brucei isolates obtained from Uganda and southwestern Kenya into three distinct genetic clusters. Clusters 1 and 3 include isolates from central and southern Uganda, while cluster 2 contains mostly isolates from southwestern Kenya. These three clusters are not sorted by subspecies designation (T. b. brucei vs T. b. rhodesiense), host or date of collection. The analyses also show evidence of genetic admixture among the three genetic clusters and long-range dispersal, suggesting recent and possibly on-going gene flow between them.Conclusions
Our results show that the expansion of the disease to the new foci in central Uganda occurred from the northward spread of T. b. rhodesiense (Tbr). They also confirm the emergence of the human infective strains (Tbr) from non-infective T. b. brucei (Tbb) strains of different genetic backgrounds, and the importance of cattle as Tbr reservoir, as confounders that shape the epidemiology of sleeping sickness in the region. 相似文献10.
Background
The current spread of the gene encoding the metallo-ß-lactamase NDM-1 in Enterobacteriaceae is linked to a variety of surrounding genetic structures and plasmid scaffolds.Methodology
The whole sequence of plasmid pGUE-NDM carrying the bla NDM-1 gene was determined by high-density pyrosequencing and a genomic comparative analysis with other bla NDM-1-negative IncFII was performed.Principal Findings
Plasmid pGUE-NDM replicating in Escherichia coli confers resistance to many antibiotic molecules including β-lactams, aminoglycosides, trimethoprim, and sulfonamides. It is 87,022 bp in-size and carries the two β-lactamase genes bla NDM-1 and bla OXA-1, together with three aminoglycoside resistance genes aacA4, aadA2, and aacC2. Comparative analysis of the multidrug resistance locus contained a module encompassing the bla NDM-1 gene that is actually conserved among different structures identified in other enterobacterial isolates. This module was constituted by the bla NDM-1 gene, a fragment of insertion sequence ISAba125 and a bleomycin resistance encoding gene.Significance
This is the first characterized bla NDM-1-carrying IncFII-type plasmid. Such association between the bla NDM-1 gene and an IncFII-type plasmid backbone is extremely worrisome considering that this plasmid type is known to spread efficiently, as examplified with the worldwide dissemination of bla CTX-M-15-borne IncFII plasmids. 相似文献11.
Objectives
The objective of this study was to determine the occurrence of chromosomal and plasmid-mediated β-lactamases (AmpC) genes in a collection of Malaysian isolates of Enterobacter species. Several phenotypic tests for detection of AmpC production of Enterobacter spp. were evaluated and the agreements between tests were determined.Methods
Antimicrobial susceptibility profiles for 117 Enterobacter clinical isolates obtained from the Medical Microbiology Diagnostic Laboratory, University Malaya Medical Centre, Malaysia, from November 2012—February 2014 were determined in accordance to CLSI guidelines. AmpC genes were detected using a multiplex PCR assay targeting the MIR/ACT gene (closely related to chromosomal EBC family gene) and other plasmid-mediated genes, including DHA, MOX, CMY, ACC, and FOX. The AmpC β-lactamase production of the isolates was assessed using cefoxitin disk screening test, D69C AmpC detection set, cefoxitin-cloxacillin double disk synergy test (CC-DDS) and AmpC induction test.Results
Among the Enterobacter isolates in this study, 39.3% were resistant to cefotaxime and ceftriaxone and 23.9% were resistant to ceftazidime. Ten (8.5%) of the isolates were resistant to cefepime, and one isolate was resistant to meropenem. Chromosomal EBC family gene was amplified from 36 (47.4%) E. cloacae and three (25%) E. asburiae. A novel blaDHA type plasmid-mediated AmpC gene was identified for the first time from an E. cloacae isolate. AmpC β-lactamase production was detected in 99 (89.2%) of 111 potential AmpC β-lactamase producers (positive in cefoxitin disk screening) using D69C AmpC detection set. The detection rates were lower with CC-DDS (80.2%) and AmpC induction tests (50.5%). There was low agreement between the D69C AmpC detection set and the other two phenotypic tests. Of the 40 isolates with AmpC genes detected in this study, 87.5%, 77.5% and 50.0% of these isolates were positive by the D69C AmpC detection set, CC-DDS and AmpC induction tests, respectively.Conclusions
Besides MIR/ACT gene, a novel plasmid-mediated AmpC gene belonging to the DHA-type was identified in this study. Low agreement was noted between the D69C AmpC detection set and two other phenotypic tests for detection of AmpC production in Enterobacter spp. As plasmid-mediated genes may serve as the reservoir for the emergence of antibiotic resistance in a clinical setting, surveillance and infection control measures are necessary to limit the spread of these genes in the hospital. 相似文献12.
Shu Xia Xin Fan Zengguang Huang Liang Xia Meng Xiao Rongchang Chen Yingchun Xu Chao Zhuo 《PloS one》2014,9(7)
Objective
To investigate CTX-M genotypes among extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) isolated from patients with community-onset and hospital-onset infections in China, their clonality and the distribution of CTX-M variants in different specimens of community-onset and hospital-onset infections.Methods
ESBL-EC isolates were collected from general hospitals from 2011 to 2012 in China. Broth microdilution method antimicrobial susceptibility testing of 16 antibiotics was performed. Clinical data from community-onset and hospital-onset infections due to ESBL-EC were analyzed. ESBL-encoding genes were amplified by PCR and sequenced, and multilocus sequence typing (MLST) was performed for a random selection of predominant CTX-M type strains identified.Results
A total of 1,168 ESBL-EC isolates were obtained from various clinical specimens, 41.7% of which were responsible for causing community-onset infections. The presence of urinary calculi was higher in community-onset infections, whereas malignancy, cardiovascular and cerebrovascular diseases, dementia, chronic renal disease, diabetes mellitus and surgical treatment were found to have higher proportions in hospital-onset infections. There was no significant difference in trauma between community-onset and hospital-onset infections. 96.2% of the isolates were detected to harbor bla CTX-M genes. bla CTX-M-1 group and bla CTX-M-9 group were detected at 40.7% and 48.7% respectively, and both positive group accounted for 10.6%. bla CTX-M-55 (24.8%) and bla CTX-M-15 (18.2%) were the major genotypes in bla CTX-M-1 group while bla CTX-M-14 (46.8%) was predominant in bla CTX-M-9 group. A comparison of bla CTX-M distribution in different specimens between ESBL-EC causing community-onset and hospital-onset infection showed no significant difference. A total of 229 isolates were tested for MLST. ST131 (14%) was the predominant type. ST648, ST405 and ST1193 were also detected.Conclusions
Community-onset ESBL-EC has emerged as a common pathogen in China. CTX-M-14 is the most commonly encountered, CTX-M-55 and CTX-M-15 have spread rapidly. ST131 is the predominant clonal group, and the great diversity of CTX-M-producing isolates of E. coli has emerged in China. 相似文献13.
Nahed Al Laham José R. Mediavilla Liang Chen Nahed Abdelateef Farid Abu Elamreen Christine C. Ginocchio Denis Pierard Karsten Becker Barry N. Kreiswirth 《PloS one》2015,10(3)
Background
Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen in both community and healthcare-related settings worldwide. Current knowledge regarding the epidemiology of S. aureus and MRSA in Gaza is based on a single community-based carriage study. Here we describe a cross-sectional analysis of 215 clinical isolates collected from Al-Shifa Hospital in Gaza during 2008 and 2012.Methods
All isolates were characterized by spa typing, SCCmec typing, and detection of genes encoding Panton-Valentine leukocidin (PVL) and toxic shock syndrome toxin (TSST-1). Representative genotypes were also subjected to multilocus sequence typing (MLST). Antibiotic susceptibility testing was performed using VITEK2 and MicroScan.Results
MRSA represented 56.3% of all S. aureus strains, and increased in frequency from 2008 (54.8%) to 2012 (58.4%). Aside from beta-lactams, resistance was observed to tetracycline, erythromycin, clindamycin, gentamicin, and fluoroquinolones. Molecular typing identified 35 spa types representing 17 MLST clonal complexes (CC), with spa 998 (Ridom t223, CC22) and spa 70 (Ridom t044, CC80) being the most prevalent. SCCmec types I, III, IV, V and VI were identified among MRSA isolates, while type II was not detected. PVL genes (lukF/S-PV) were detected in 40.0% of all isolates, while the TSST-1 gene (tst) was detected in 27.4% of all isolates, with surprisingly high frequency within CC22 (70.4%). Both PVL and TSST-1 genes were found in several isolates from 2012.Conclusions
Molecular typing of clinical isolates from Gaza hospitals revealed unusually high prevalence of TSST-1 genes among CC22 MRSA, which is noteworthy given a recent community study describing widespread carriage of a CC22 MRSA clone known as the ‘Gaza strain’. While the latter did not address TSST-1, tst-positive spa 998 (Ridom t223) has been detected in several neighboring countries, and described as endemic in an Italian NICU, suggesting international spread of a ‘Middle Eastern variant’ of pandemic CC22 strain EMRSA-15. 相似文献14.
15.
Objectives
The study aimed to investigate the prevalence and epidemiological characteristics of bla NDM-1 (encoding New Delhi metallo-β-lactamase 1) in Enterobacteriaceae and the Acinetobacter calcoaceticus-Acinetobacter baumannii complex (ABC) in China from July 2011 to June 2012.Methods
PCR was used to screen for the presence of bla NDM-1 in all organisms studied. For bla NDM-1-positive strains, 16S rRNA analysis and Analytical Profile Index (API) strips were used to identify the bacterial genus and species. The ABCs were reconfirmed by PCR detection of bla OXA-51-like. Antibiotic susceptibilities of the bacteria were assessed by determining minimum inhibitory concentration (MIC) of them using two-fold agar dilution test, as recommended by the Clinical and Laboratory Standards Institute (CLSI). Molecular typing was performed using pulsed-field gel electrophoresis (PFGE). S1 nuclease-pulsed-field gel electrophoresis (S1-PFGE) and Southern blot hybridization were conducted to ascertain the gene location of bla NDM-1. Conjugation experiments were conducted to determine the transmission of bla NDM-1-positive strains.Results
Among 2,170 Enterobacteriaceae and 600 ABCs, seven Enterobacteriaceae strains and two A. calcoaceticus isolates from five different cities carried the bla NDM-1 gene. The seven Enterobacteriaceae strains comprised four Klebsiella pneumoniae, one Enterobacter cloacae, one Enterobacter aerogen and one Citrobacter freundii. All seven were non-susceptible to imipenem, meropenem or ertapenem. Two A. calcoaceticus species were resistant to imipenem and meropenem. Three K. pneumoniae showed the same PFGE profiles. The bla NDM-1 genes of eight strains were localized on plasmids, while one was chromosomal.Conclusions
Compared with previous reports, the numbers and species containing the bla NDM-1 in Enterobacteriaceae have significantly increased in China. Most of them are able to disseminate the gene, which is cause for concern. Consecutive surveillance should be implemented and should also focus on the dissemination of bla NDM-1 among gram-negative clinical isolates. 相似文献16.
Ping Wang Jing-jing Tong Xiu-hua Ma Feng-li Song Ling Fan Cui-mei Guo Wei Shi Sang-jie Yu Kai-hu Yao Yong-hong Yang 《PloS one》2015,10(3)
Background
To investigate the serotypes, antibiotic susceptibilities, and multi-locus sequence type (MLST) profiles of Streptococcus agalactiae (S. agalactiae) in Beijing to provide references for the prevention and treatment of S. agalactiae infections.Methods
All isolates were identified using the CAMP test and the latex-agglutination assay and serotyped using a Strep-B-Latex kit, after which they were assessed for antibiotic susceptibility, macrolide-resistance genes, and MLST profiles.Results
In total, 56 S. agalactiae isolates were identified in 863 pregnant women (6.5%). Serotypes Ia, Ib, II, III, and V were identified, among which types III (32.1%), Ia (17.9%), Ib (16.1%), and V (14.3%) were the predominant serotypes. All isolates were susceptible to penicillin and ceftriaxone. The nonsusceptiblity rates measured for erythromycin, clarithromycin, azithromycin, telithromycin, clindamycin, tetracycline, and levofloxacin were 85.7%, 92.9%, 98.2%, 30.4%, 73.2%, 91%, and 39.3%, respectively. We identified 14 sequence types (STs) for the 56 isolates, among which ST19 (30.4%) was predominant. The rate of fluoroquinolone resistance was higher in serotype III than in the other serotypes. Among the 44 erythromycin-resistant isolates, 32 (72.7%) carried ermB.Conclusion
S. agalactiae isolates of the serotypes Ia, Ib, III, and V are common in Beijing. Among the S. agalactiae isolates, the macrolide and clindamycin resistance rates are extremely high. Most of the erythromycin-resistant isolates carry ermB. 相似文献17.
Ji Zhang Fei-Fei Gu Sheng-Yuan Zhao Shu-Zhen Xiao Yan-Chun Wang Xiao-Kui Guo Yu-Xing Ni Li-Zhong Han 《PloS one》2015,10(9)
Background
Residents in nursing homes (NHs) always represent potential reservoirs for Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). To our knowledge, there is no epidemiological information up till now that describes the prevalence and molecular characteristics of S. aureus in nursing home residents in Shanghai, China.Methods
Four hundred and ninety-one unique residents from 7 NHs were enrolled in this study. Specimens were collected among these residents including 491 nasal swabs, 487 axillary swabs and 119 skin swabs. S. aureus isolated and identified from the swabs was characterized according to antimicrobial susceptibility profiling, toxin gene prevalence, and multilocus sequence typing (MLST), spa and SCCmec typing.Results
Among the 491 residents screened, S. aureus was isolated in 109 residents from 90 nasal swabs (90/491, 18.3%), 29 axillary swabs (29/487, 6.0%), and 22 skin swabs (22/119, 18.5%). Sixty-eight MRSA isolates were detected in 52 residents from 41 nasal carriers, 15 axillary carriers and 12 skin carriers. The overall prevalence rate of S. aureus and MRSA colonization was 22.2% and 10.6% respectively. Ten residents presented S. aureus in all three sample types and 12 residents presented S. aureus in two of the three sample types collected. Molecular analysis revealed CC1 (29.1%) to be the dominant clone in this study, followed by CC398 (19.9%), CC188 (13.5%) and CC5 (12.8%). The most common spa type was t127 (22.0%), followed by t14383 (12.8%) and t002 (10.6%).Conclusions
A high prevalence of S. aureus and MRSA colonization was revealed in nursing home residents in Shanghai. CC1 was the most common clonal complex and t127 was the most common spa type among NH residents. The data provides an important baseline for future surveillance of S. aureus in NHs in Shanghai and other highly urbanized regions in China. Implementation of infection control strategies must be given high priority in NHs to fight such high prevalence of both MRSA and methicillin-susceptible S. aureus (MSSA). 相似文献18.
Gloria Puerto Lina Erazo Maira Wintaco Claudia Castro Wellman Ribón Martha Inírida Guerrero 《PloS one》2015,10(6)
Introduction
Tuberculosis (TB) remains a primary public health problem worldwide. The number of multidrug-resistant tuberculosis (MDR TB) cases has increased in recent years in Colombia. Knowledge of M. tuberculosis genotypes defined by spoligotyping can help determine the circulation of genotypes that must be controlled to prevent the spread of TB.Objective
To describe the genotypes of M. tuberculosis using spoligotyping in resistant and drug-sensitive isolates and their possible associations with susceptibility to first-line drugs.Methods
An analytical observational study was conducted that included 741 isolates of M. tuberculosis from patients. The isolates originated from 31 departments and were obtained by systematic surveillance between 1999 and 2012.Results
In total 61.94% of the isolates were resistant to 1 or more drugs, and 147 isolates were MDR. In total, 170 genotypes were found in the population structure of Colombian M. tuberculosis isolates. The isolates were mainly represented by four families: LAM (39.9%), Haarlem (19%), Orphan (17%) and T (9%). The SIT42 (LAM 9) was the most common genotype and contained 24.7% of the isolates, followed by the genotypes SIT62 (Haarlem1), SIT53 (T1), and SIT50 (H3). A high clustering of isolates was evident with 79.8% of the isolates classified into 32 groups. The Beijing family was associated with resistant isolates, whereas the Haarlem and T families were associated with sensitive isolates. The Haarlem family was also associated with grouped isolates (p = 0.031).Conclusions
A high proportion (approximately 80%) of isolates was found in clusters; these clusters were not associated with resistance to first-line drugs. The Beijing family was associated with drug resistance, whereas the T and Haarlem families were associated with susceptibility in the Colombian isolates studied. 相似文献19.
Antonia P. Popova Tracy X. Cui Niko Kaciroti Adam M. Goldsmith Marisa J. Linn Gloria S. Pryhuber Marc B. Hershenson 《PloS one》2015,10(12)