RESUMO
Objective To investigate the antimicrobial characteristics of shigella flexneri and to analyze the correlation between acquired resistance genes and mobile genetic elements.Methods 139 strains of shigella flexneri collected from each district of Centers for Disease Control and Prevention in Shanghai from 2010 to 2014 were recovered.The K-B method was used to determine the susceptibility of the strains to 13 antibiotics.And then 17 kinds of acquired resistance genes to β-lactams, sulfonamides, aminoglycosides and 7 kinds of genetic markers of mobile genetic elements were analyzed by PCR.Index cluster analysis was performed to explore the correlation between them.Results Among 139 strains of Shigella flexneri,3 kinds of genetic markers of mobile genetic elements,ISEcp1,intI1 and trbC,3 kinds of acquired β-lactam-resistance genes,CTX-M,OXA and TEM,2 kinds of acquired aminoglycoside-resistance genes,ant(3")-I and aac(6′)-Ib, 1 kind of overlapping gene of quaternary ammonium disinfectant and sulfonamides, qacEΔ1-sull and 1 kind of sulfamethoxazole/trimethoprim-resistant gene, dfrA1 were detected.The resistence genes,OXA,ant(3")-I and drfA1 were highly related with each other,which were mediated by Class 1 integron.TEM,qacEΔl-sull and aac(6′)-Ib were highly related with each other,which were mediated by trbC.Conclusion Acquired multidrug resistance gene transfer mediated by a variety of mobile genetic elements may have largely contributed to the spreading of resistant strains of Shigella.
RESUMO
We investigated molecular identification of a group of 14 strains of Aeromonas sp .,and genetic background of re‐sistance to beta‐lactams ,aminoglycosides .From January to December 2012 ,14 strains of Aeromonas sp .were collected from stool from diarrheal patients in enteric clinics in Ningbo First Hospital in Zhejiang Province ,China .Then ,molecular identifica‐tion by 16SrDNA ,23 kinds of beta‐lactamase genes ,6 kinds of aminoglycoside modifying enzyme genes ,6 kinds of 16srRNA methylase genes ,and 6 kinds of mobile genetic elements were analyzed by PCR .In addition ,genotyping and sample cluster a‐nalysis were performed .Results showed that 10 strains of A .hydrophila ,1 strain of A .aquariorum ,A .sobria ,A .entero‐pelogenes ,A .punctata were confirmed by 16SrDNA sequencing and arithmetic .Five kinds of beta‐lactamase genes ,4 kinds of aminoglycoside modifying enzyme genes ,and 3 kinds of mobile genetic elements were positive .BlaAQU of strain No .4(AQU‐2) and strain No .11(AQU‐3) were new subtypes .It’s suggested that identification of Aeromonas sp .should be performed by molecular identification method .This group of 14 strains of Aeromonas sp .conferred multidrug resistance .
RESUMO
Objective To investigate the correlation between drug-resistant genes and mobile genetic elements in multi-drug resistant Escherichia coli,and to explore phylogeny among the strains.MethodsTotally 20 strains of multi-drug resistant Escherichia coli were collected from Pan' an Hospital,Zhejiang Province during June 2009 and June 2010.Beta-lactam-resistance genes,aminoglycoside-resistance genes,genetic markers of mobile genetic elements were analyzed by PCR.Index and sample cluster analysis were performed on above results. Results In 20 strains of Escherichia coli,4 kinds of beta-lactamresistance genes,4 kinds of aminoglycoside-resistance genes,and 5 kinds of genetic markers of mobile genetic elements were detected.Index cluster analysis showed that correlation existed between resistance genes TEM,CTX-M-1,aadA5 and mobile genetic elements traA,IS26,ISEcpl; and correlation also existed between resistance genes OXA-1,aac(6′)-Ⅰ b,ant(3)-Ⅰ,rmtB and mobile genetic elements trbC,IS903.Sample cluster analysis showed that this group of Escherichia coli could be divided into 2 groups which were genetically different.ConclusionsDrug-resistant genes in multi-drug resistant Escherichia coli are correlated with mobile genetic elements.Sample cluster analysis can reveal phylogeny among the strains,which is important for hospital infection control.
RESUMO
Objective To investigate the distribution of acquired resistance-related genes and markers of mobile genetic elements, and their relationships in multidrug-resistant Escherichia coli. Methods From October 2008 to March 2009, 28 strains of multidrug-resistant Escherichia coli isolated from urine were collected from the Ningbo First Hospital. Then, 47 kinds of acquired resistance genes to beta-lactams, aminoglycosides, quinolones, 2 kinds of acquired drug efflux gene and 13 kinds of genetic markers of mobile genetic elements: conjugal plasmids, transposons, insertion sequences, and integrons were analyzed by PCR. The index cluster analysis was used to investigate their relationships. Results In 28 strains of Escherichia coli, 7 kinds of acquired beta-lactam-resistance genes, 8 kinds of acquired aminoglycosideresistance genes, 1 kind of acquired drug efflux gene, 2 kinds of genetic markers of conjugal plasmids, 3 kinds of genetic markers of transposon and insertion sequences, 1 kind of genetic marker of integron were detected; but other 46 kinds of genes were not detected. Two clusters, A and B, were divided by index cluster analysis depending on positive genes. Conclusions In this group of Escherichia coli, acquired resistance related genes may be associated with resistant phenotypes of antimicrobial agents. Horizontal transfer of mobile genetic elements may bring rapid spread of resistance of bacterial pathogens, not only among the same kind of pathogens, but also among the different kinds. In addition, index cluster analysis suggests that correlation might exist between acquired resistance-related genes and mobile genetic elements.
RESUMO
Objective To investigate the prevalence of mobile genetic elements in Acinetobacter baumannii strains isolated from burn patients. Methods Polymerase chain reaction (PCR) was used to detect the genes encoding the integron, transposon, conjugative plasmid and insertion sequence in 20 strains of Acinetobacter baumannii isolated from burn patients. Results tnpU and ISaba1 genes were detected in all 20 strains, and int Ⅰ gene was detected in 19 strains (95.0%). Other genes were all negative. Conclusion Mobile genetic elements carrying multi-drug resistant genes are found in Acinctobacter baumannii strains isolated from bum patients.
RESUMO
En Colombia se han detectado genes del grupo CTX-M-1 con alta frecuencia en aislamientos de Klebsiella pneumoniae causantes de infección intrahospitalaria. El conocimiento de los factores genéticos que pueden favorecer la diseminación de estos genes entre especies bacterianas es un aspecto importante para el control de la resistencia. En este estudio se identificaron los plásmidos portadores del gen blaCTX-M-12 en 21 aislamientos clínicos de K. pneumoniae. Se evaluó por conjugación la transferencia de resistencia a antibióticos. Integrones, secuencias de inserción y otros elementos genéticos fueron detectados por amplificación del ADN plasmídico con la reacción en cadena de la polimerasa (PCR). Mediante análisis por PCR se determinó la relación entre el gen blaCTX-M-12 y los elementos genéticos detectados. En todos los aislamientos, el gen blaCTX-M-12 se encontró en plásmidos conjugativos de tamaños entre 65 y 106 kpb. La transferencia por conjugación de estos elementos móviles puede explicar la amplia diseminación de este gen entre enterobacterias causantes de infección nosocomial en hospitales de Bogotá, Colombia. El gen blaCTX-M-12 se encontró corriente abajo de ISEcp1, secuencia de inserción que se ha asociado con la movilización de determinantes genéticos de resistencia. Los promotores de ISEcp1, detectados por análisis de secuencia, pueden facilitar la expresión de la cefotaximasa codificada por este gen.
Genes from CTX-M-1 group have been detected with great frequency in Colombia in intrahospital infection-causing Klebsiella pneumoniae isolates. Knowledge regarding the genetic factors favouring such genesâ dissemination amongst bacterial species is an important issue for resistance control blaCTX-M-12 gene-carrying plasmids were identified in this study in 21 clinical K. pneumoniae isolates. Antibiotic resistance transfer was evaluated by mating. Integrons, insertion sequences and other genetic elements were detected by plasmid DNA amplification using polymerase chain reaction (PCR). The relationship between the blaCTX-M-12 gene and other genetic elements was determined by PCR analysis. The blaCTX-M-12 gene was disemifound on 52 to 106 Kpb conjugative plasmids in all isolates. These mobile elementsâ transfer by mating may explain their wide dissemination amongst nosocomial infection-causing enterobacteria in hospitals in Bogota, Colombia. The blaCTX-M-12 gene was found downstream from ISEcp1, this being an insertion sequence which has been associated with resistance genetic determinantsâ mobilisation. ISEcp1 promoters (detected by sequence analysis) may increase the expression of cefotaximase encoded by this gene.