ABSTRACT
With the abuse of antimicrobial agents in developing countries, increasing number of carbapenem-resistant Enterobacteriaceae (CRE) attracted considerable public concern. A retrospective study was conducted based on 242 CRE strains from a tertiary hospital in Hangzhou, China to investigate prevalence and drug resistance characteristics of CRE in southeast China. Bacterial species were identified. Antimicrobial susceptibility was examined by broth microdilution method or epsilometer test. Resistant β-lactamase genes were identified by polymerase chain reaction and sequencing. Genotypes were investigated by phylogenetic analysis. Klebsiella pneumoniae and Escherichia coli were the most prevalent types of species, with occurrence in 71.9% and 21.9% of the strains, respectively. All strains exhibited high resistance (> 70%) against β-lactam antibiotics, ciprofloxacin, trimethoprim-sulfamethoxazole, and nitrofurantoin but exhibited low resistance against tigecycline (0.8%) and minocycline (8.3%). A total of 123 strains harbored more than two kinds of β-lactamase genes. bla, bla, bla, and bla were the predominant genotypes, with detection rates of 60.3%, 61.6%, 43.4%, and 16.5%, respectively, and were highly identical with reference sequences in different countries, indicating potential horizontal dissemination. IMP-4 was the most frequent class B metallo-lactamases in this study. In conclusion, continuous surveillance and effective prevention should be emphasized to reduce spread of CRE.
Subject(s)
Humans , Anti-Bacterial Agents , Therapeutic Uses , Carbapenem-Resistant Enterobacteriaceae , Genetics , China , Epidemiology , Enterobacteriaceae Infections , Epidemiology , Microbiology , Genotype , Microbial Sensitivity Tests , Phylogeny , Prevalence , Retrospective Studies , beta-Lactam Resistance , beta-Lactamases , GeneticsABSTRACT
To study the transmission of Salmonella and resistance genes,116 Salmonella isolates were tested the sero types,antimicrobial susceptibility,resistant genes on SG1 including β-1actamase genes,and multilocus sequence typing (MLST).Results showed that Salmonella isolates from the chicken belonged to ST11 clone,S.enteritidis,and ST17 clone,S.indiana,and from the pig belonged to ST40,S.derby mostly.ST11 clone showed multidrug-resistant (MDR),resistance to ampicillin,nalidixic acid,tetracycline,and cefoperazone,mostly.ST17 clone showed resistance to nine or more kinds of antibiotics including cephalosporins and fluouoquinolones,a super-MDR clone.ST11 clone carried bla TEM-l-like highly,whereas blaOXA-1-like,blaCTX-M,blaTEM-1-like,and floR,aadA2,sul1,and aac (6')-1b were highly carried in ST17 clone,a new super-MDR clone.The antibiotic abuse and misuse in food supply chains were the main origin of MDR and super-MDR Salmonella,which were transmitted by the chains.It is significance that the control of substance abuse,especially cephalosporins and fluouoquinolones,in food supply chains.
ABSTRACT
Introduction: Pseudomonas aeruginosa is a potent opportunistic nosocomial human pathogen among Gram-negative bacteria causing various life-threatening infections in patients from Intensive Care Units. This bacterium has become resistant to almost all commonly available antibiotics with limited treatment options. Multi drug resistant P. aeruginosa (MDRPA) is a major cause of concern among hospital acquired infections. It uses distinctive resistant mechanisms virtually to all the available antibiotics such as Metallo β-lactamases (MBL) production, extended spectrum β-lactamase production (ESBL), up regulation of effl ux systems related genes and decreased outer membrane permeability. This study was carried out to fi nd one the predominant resistance mechanisms among MDRPA and the prevalence of corresponding resistance genes. Materials and Methods: MDRPA isolates collected from various clinical samples for a period of 1-year (November 2009-Octo ber 2010) were included to detect the predominant mechanism of resistance using phenotypic and molecular methods. Molecular characterization of all these isolates was done by polymerase chain reaction (PCR) for the presence of blaVIM-2, blaIMP-1, blaOXA-23, and blaNDM-1 genes with specifi c primers. Results: Among 75 MDRPA isolates 84% (63) were MBL producers. Molecular characterization studied by PCR showed the presence of blaVIM-2 gene in 13% of MBL producers. Conclusion: The prevalence of MBLs has been increasing worldwide, particularly among P. aeruginosa, leading to severe limitations in the therapeutic options for the management. Thus, proper resistance screening measures and appropriate antibiotic policy can be strictly adopted by all the healthcare facility providers to overcome these superbugs.
ABSTRACT
ObjectiveTo investigate correlation between drug-resistance related genes and mobile genetic elements of Klebsiella pneumoniae resistant to β-lactams. Methods Forty-seven strains of multidrug-resistant Klebsiella pneumoniae were collected from 6 hospitals in Hangzhou and Huzhou of Zhejiang province from August 2008 to May 2010.Modified Hodge test was performed to detect phenotypes of carbapenemases.Forty kinds of β-lactamases (class A-D),ompK35,ompK36,and 12 kinds of mobile genetic elements were detected by PCR,and the results were analyzed by index cluster.ResultsThirty-five strains were positive in modified Hodge test,and 5 kinds of β-lactamases gene ( including KPC-2-like,GenBank:HQ258934) and 9 kinds of mobile genetic elements were detected.Mutations were observed in ompK35 and ompK36 when compared with sensitive strains.Index cluster analysis showed that correlation existed between KPC-2,KPC-2-like and ISKpn6,between TEM-1 and ISEcpl,IS26,int Ⅰ 1,trbC,IS903,and between CMY-2,OXA-30,DHA-1 and tnpU,tnp513,trbC.ConclusionsFive kinds of β-1actamases genes,and mutations in ompK35 and ompK36 may be associated with the resistance to β-1actams in multidrug-resistant Klebsiella pneumoniae.