Colicin production/resistance associated with R-plasmids of Gram negative bacteria isolated from poultry in Karachi. - Related Documents




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304801.0000Colicin production/resistance associated with R-plasmids of Gram negative bacteria isolated from poultry in Karachi. R plasmids of Gram negative bacteria isolated from poultry in Karachi were studied for their properties of colicin production and resistance. Of 39 R plasmids studied, 23 resisted colicin where as only one R-plasmid produced colicin.199816414807
179110.9993Complete genome sequence of Enterobacter cloacae R11 reveals multiple genes potentially associated with high-level polymyxin E resistance. Enterobacter cloacae strain R11 is a multidrug-resistant bacterium isolated from sewage water near a swine feedlot in China. Strain R11 can survive in medium containing up to 192 μg/mL polymyxin E, indicating a tolerance for this antibiotic that is significantly higher than that reported for other gram-negative bacteria. In this study, conjugation experiments showed that partial polymyxin E resistance could be transferred from strain R11 to Escherichia coli strain 25922, revealing that some genes related to polymyxin E resistance are plasmid-based. The complete genome sequence of this strain was determined, yielding a total of 4 993 008 bp (G+C content, 53.15%) and 4908 genes for the circular chromosome and 4 circular plasmids. Genome analysis revealed a total of 73 putative antibiotic resistance genes, including several polymyxin E resistance genes and genes potentially involved in multidrug resistance. These data provide insights into the genetic basis of the polymyxin E resistance and multidrug resistance of E. cloacae.201829073359
585520.9993Plasmid-encoded resistance to arsenic compounds in Gram-negative bacteria isolated from a hospital environment in Venezuela. Resistance to arsenic compounds was examined among amikacin resistant Gram-negative bacteria isolate from a hospital environment. Arsenite resistance (Ars(r)) was found in a high proportion of isolates ( >60%) being frequently associated with resistance to tellurite (40%), and to other antimicrobial agents. Ars determinants (27%) were found to be transferable to E. coli K12 strains from which large plasmid DNA molecules were isolated and characterized by agarose gel electrophoresis. Plasmids were identified by both classical incompatibility tests, and by replicon typing using DNA specific probes. Most of the amikacin-arsenite (Ak-Ars) conjugative plasmids belong to the H incompatibility group. These results suggest that Ak-Ars resistance linked to IncH plasmids is wide spread in Gram-negative bacteria.199718611788
585130.9993Arsenic resistance determinants from environmental bacteria. Arsenic resistance determinants from 42 environmental bacterial isolates (32 Gram negative) were analyzed by DNA: DNA hybridization using probes derived from Escherichia coli and Staphylococcus plasmid or chromosomal arsenic resistance (ars) genes. In colony hybridization assays, 11 and 1 Gram negative strains hybridized with the E. coli chromosome and plasmid probes, respectively. No hybridization was detected using a probe containing only the arsA (ATPase) gene from E. coli plasmid or with a Staphylococcus plasmid ars probe. From Southern hybridization tests of some of the positive strains it was concluded that homology to ars chromosomal genes occurred within chromosome regions, except in an E. coli isolate where hybridization occurred in both the chromosome and a 130-kb plasmid. Our results show that DNA sequences homologous to E. coli ars chromosomal genes are commonly present in the chromosomes of environmental arsenic-resistant Gram negative isolates.199810932734
585440.9993Discovery of a gene conferring multiple-aminoglycoside resistance in Escherichia coli. Bovine-origin Escherichia coli isolates were tested for resistance phenotypes using a disk diffusion assay and for resistance genotypes using a DNA microarray. An isolate with gentamicin and amikacin resistance but with no corresponding genes detected yielded a 1,056-bp DNA sequence with the closest homologues for its inferred protein sequence among a family of 16S rRNA methyltransferase enzymes. These enzymes confer high-level aminoglycoside resistance and have only recently been described in Gram-negative bacteria.201020368404
595350.9992CAT III chloramphenicol resistance in Pasteurella haemolytica and Pasteurella multocida isolated from calves. Chloramphenicol, which had been used extensively for antimicrobial veterinary therapy, was prohibited in Europe in 1994. Soon after it became available, resistance to this drug was detected, generally conferred by plasmids encoding inactivating enzymes, the chloramphenicol acetyltransferases (CAT), in Gram-negative as well as in Gram-positive bacteria. In the last few years, resistance to antibiotics emerged in Pasteurella strains from breeding herds and this evolution was followed by a national surveillance network. Chloramphenicol-resistance was more recently detected in multiresistant strains. We studied 25 strains of Pasteurella, selected for their resistance to chloramphenicol. Production of a CAT was demonstrated in all these strains. PCR amplification indicated that the CAT produced was of type III for 23 of them. In these strains, chloramphenicol-resistance was mediated by plasmids of about 5.1 kb. Southern blots on restriction fragments suggested a high degree of homology between these 5.1 kb plasmids. In the two other strains, production of a CAT type I was demonstrated, and the corresponding genes were either shown on a plasmid of 17 or 5.5 kb.19968877534
585360.9992Identification of the tet(B) resistance gene in Streptococcus suis. The tetracycline resistance gene, tet(B), has been described previously in gram negative bacteria. In this study tet(B) was detected in plasmid extracts from 17/111 (15%) Streptococcus suis isolates from diseased pigs, representing the first report of this resistance gene in gram positive bacteria.201120696603
304570.9992Plasmid-borne sulfonamide resistance determinants studied by restriction enzyme analysis. The relationship between sulfonamide resistance genes carried on different plasmids was investigated by restriction enzyme analysis and DNA-DNA hybridization. The results showed that sulfonamide resistance mediated by different plasmids is determined by the production of at least two different types of drug-resistant dihydropteroate synthase. Plasmids pGS01, pGS02, and R22259, found in bacteria isolated from patients in Swedish hospitals, contained identical sulfonamide resistance genes, which were also identical to those of plasmids R1, R100, R6, and R388. These latter plasmids, which have been well studied in different laboratories, were originally from clinical isolates from different parts of the world. Two other clinically isolated plasmids, pGS04 and pGS05, were shown to contain sulfonamide resistance determinants of a completely different type.19836298179
197380.9992Draft Genome Sequences of Multidrug-Resistant Escherichia coli Strains Isolated from River Water in Malaysia. Antimicrobial resistance has become a primary concern in clinical and public health. Escherichia coli is one of the bacteria that carries and disseminates antimicrobial resistance genes to the community. Here, we report the draft genome sequence of three multidrug-resistant E. coli strains that were isolated from river water in Malaysia.202235678586
305090.9992The type VII dihydrofolate reductase: a novel plasmid-encoded trimethoprim-resistant enzyme from gram-negative bacteria isolated in Britain. Plasmid pUN835 was identified in an Escherichia coli strain isolated from an outbreak of porcine diarrhoea on a farm near Nottingham, UK. The trimethoprim resistance gene did not hybridize with any of the gene probes derived from known plasmid-encoded trimethoprim resistance genes. The trimethoprim resistance gene of pUN835 was shown to encode the production of a dihydrofolate reductase which confers high-level resistance on its host. This enzyme was smaller than most plasmid-encoded dihydrofolate reductases (molecular mass = 11,500) and was labile to heat. It had relatively low affinity for the substrate dihydrofolate (Km = 20 microM) and it was resistant to competitive inhibition by trimethoprim (Ki = 7.0 microM). We classify this novel enzyme as type VII.19892676936
2073100.9992Plasmid-related quinolone resistance determinants in epidemic Vibrio parahaemolyticus, uropathogenic Escherichia coli, and marine bacteria from an aquaculture area in Chile. Marine bacteria from aquaculture areas with industrial use of quinolones have the potential to pass quinolone resistance genes to animal and human pathogens. The VPA0095 gene, related to the quinolone resistance determinant qnrA, from clinical isolates of epidemic Vibrio parahaemolyticus conferred reduced susceptibility to quinolone after cloning into Escherichia coli K-12 either when acting alone or synergistically with DNA gyrase mutations. In addition, a plasmid-mediated quinolone resistance gene from marine bacteria, aac(6')-Ib-cr, was identical to aac(6')-Ib-cr from urinary tract isolates of E. coli, suggesting a recent flow of this gene between these bacteria isolated from different environments. aac(6')-Ib-cr from E. coli also conferred reduced susceptibility to quinolone and kanamycin when cloned into E. coli K-12.201424760167
5956110.9992Gentamicin resistance in clinical isolates of Escherichia coli encoded by genes of veterinary origin. Seven (27%) of 26 gentamicin-resistant human clinical isolates of Escherichia coli were resistant to the veterinary aminoglycoside antibiotic apramycin. A gentamicin-resistant Klebsiella pneumoniae isolate from a patient infected with gentamicin/apramycin-resistant E. coli was also resistant to apramycin. DNA hybridisation studies showed that all gentamicin/apramycin-resistant isolates contained a gene encoding the enzyme 3-N-aminoglycoside acetyltransferase type IV (AAC[3]IV) that mediates resistance to gentamicin and apramycin in bacteria isolated from animals. Seven of the eight gentamicin/apramycin-resistant isolates were also resistant to the veterinary antihelminthic agent hygromycin B, a phenomenon observed previously in gentamicin/apramycin-resistant Enterobacteriaceae isolated from animals. Resistance to gentamicin/apramycin and hygromycin B was co-transferable in six of the isolates. Restriction enzyme analysis of plasmids in apramycin-resistant transconjugants derived from E. coli and K. pneumoniae isolates from the same patient were virtually identical, suggesting that inter-generic transfer of plasmids encoding apramycin resistance had occurred in vivo. These findings support the view that resistance to gentamicin and apramycin in clinical isolates of E. coli results from the spread of resistant organisms from animals to man, with subsequent inter-strain or inter-species spread, or both, of resistance genes on transferable plasmids.19948114074
4957120.9992Plasmid-mediated quinolone resistance gene detected in Escherichia coli from cattle. Fluoroquinolones resistance in bacteria can be due to chromosomal and plasmid-mediated mechanisms. Of growing concern is the acquisition of genes encoding quinolone resistance in combination with other resistance mechanisms such as extended-spectrum beta-lactamases. In this study we describe the identification of an isolate of Escherichia coli from cattle which carried qnrS1 in combination with a blaCTX-M gene, although they were not co-localised on the same plasmid. In addition, using a DNA array it was possible to identify several other antimicrobial resistance genes in this isolate. This is the first report of a qnr gene in E. coli from cattle in the UK and highlights the need for surveillance of these emerging resistance mechanisms.201120884136
5976130.9992fosM, a New Family of Fosfomycin Resistance Genes Identified in Bacterial Species Isolated from Human Microbiota. Fosfomycin is a decades-old antibiotic, currently reused because of its activity against multidrug-resistant bacteria. Here, we used a combined in vitro/in silico approach to search for fosfomycin resistance determinants in 25 new bacterial species isolated from the human microbiota. Putative resistance genes were cloned into a susceptible Escherichia coli strain. MIC values increased from 1 μg/ml to 1,024 μg/ml. Here, we report a new family of potential chromosomal fosfomycin resistance genes, named fosM.202133199384
5850140.9991Gram-positive merA gene in gram-negative oral and urine bacteria. Clinical mercury resistant (Hg(r)) Gram-negative bacteria carrying Gram-positive mercury reductase (merA)-like genes were characterized using DNA-DNA hybridization, PCR and sequencing. A PCR assay was developed which discriminated between the merA genes related to Staphylococcus and those related to the Bacillus/Streptococcus merA genes by the difference in size of the PCR product. DNA sequence analysis correlated with the PCR assay. The merA genes from Acinetobacter junii, Enterobacter cloacae and Escherichia coli were sequenced and shared 98-99% identical nucleotide (nt) and 99.6-100% amino acid identity with the Staphylococcus aureus MerA protein. A fourth merA gene, from Pantoeae agglomerans, was partially sequenced (60%) and had 99% identical nt and 100% amino acid identity with the Streptococcus oralis MerA protein. All the Hg(r) Gram-negative bacteria transferred their Gram-positive merA genes to a Gram-positive Enterococcus faecalis recipient with the resulting transconjugants expressing mercury resistance. These Gram-positive merA genes join Gram-positive tetracycline resistance and Gram-positive macrolide resistance genes in their association with mobile elements which are able to transfer and express in Gram-negative bacteria.200415358427
5969150.9991Microarray-based detection of 90 antibiotic resistance genes of gram-positive bacteria. A disposable microarray was developed for detection of up to 90 antibiotic resistance genes in gram-positive bacteria by hybridization. Each antibiotic resistance gene is represented by two specific oligonucleotides chosen from consensus sequences of gene families, except for nine genes for which only one specific oligonucleotide could be developed. A total of 137 oligonucleotides (26 to 33 nucleotides in length with similar physicochemical parameters) were spotted onto the microarray. The microarrays (ArrayTubes) were hybridized with 36 strains carrying specific antibiotic resistance genes that allowed testing of the sensitivity and specificity of 125 oligonucleotides. Among these were well-characterized multidrug-resistant strains of Enterococcus faecalis, Enterococcus faecium, and Lactococcus lactis and an avirulent strain of Bacillus anthracis harboring the broad-host-range resistance plasmid pRE25. Analysis of two multidrug-resistant field strains allowed the detection of 12 different antibiotic resistance genes in a Staphylococcus haemolyticus strain isolated from mastitis milk and 6 resistance genes in a Clostridium perfringens strain isolated from a calf. In both cases, the microarray genotyping corresponded to the phenotype of the strains. The ArrayTube platform presents the advantage of rapidly screening bacteria for the presence of antibiotic resistance genes known in gram-positive bacteria. This technology has a large potential for applications in basic research, food safety, and surveillance programs for antimicrobial resistance.200515872258
2080160.9991Distribution of the antiseptic-resistance genes qacE and qacE delta 1 in gram-negative bacteria. The distribution of the antiseptic-resistance genes qacE and qacE delta 1 was studied in a large number of Gram-negative bacteria by a method that included the polymerase chain reaction (PCR). A total of 117 strains of Gram-negative bacteria, isolated from clinical or environmental sources, was used in this analysis. We demonstrated the presence of these genes in 48 of 78 strains of Pseudomonas, in 20 of 26 strains of Vibrio, and in four of 13 strains of other species. These results indicate that the antiseptic-resistance genes are present in a broad range of species of Gram-negative bacteria.19989503610
2081170.9991Distribution of the antiseptic-resistance gene qacE delta 1 in gram-positive bacteria. The distribution of the antiseptic-resistance genes qacE and qacE delta 1, originally isolated from Gram-negative bacteria, was studied in a large number of Gram-positive bacteria by a method that included the polymerase chain reaction. A total of 151 strains of Staphylococcus and Enterococcus, isolated from clinical sources and obtained from the Japanese Collection of Microorganisms, was used in this analysis. We found the qacE delta 1 gene in 36 of 103 strains of Staphylococcus and in nine of 48 strains of Enterococcus. All of the strains in which we detected the qacE delta 1 gene were clinical isolates. The qacE gene was not detected in any of the strains examined in this study. The nucleotide sequences of the qacE delta 1 genes from the strains of Staphylococcus and Enterococcus were identical to that of the gene located on integron InC in Pseudomonas aeruginosa. These results indicate that the antiseptic-resistance gene qacE delta 1 is present in Gram-positive, as well as Gram-negative, bacteria.19989742702
5987180.9991Mutations in gyrA and parC QRDRs are not relevant for quinolone resistance in epidemiological unrelated Stenotrophomonas maltophilia clinical isolates. Clinical strains of Stenotrophomonas maltophilia are often highly resistant to multiple antibiotics and this resistance is steadily rising. Quinolones are included in the group of antimicrobial agents to which this microorganism is developing resistance. Therefore, the aim of this study was to analyze the epidemiological relationship among 22 clinical isolates of S. maltophilia as well as the molecular mechanisms responsible for the acquisition of quinolone-resistance in these strains. The results of the pulsed-field gel electrophoresis (PFGE) showed an heterogenicity of 82% among the strains used in the study. On the other hand, no amino acid changes were found in the quinolone resistance-determining region (QRDR) of either gyrA and parC genes among quinolone-susceptible and -resistant S. maltophilia strains. Besides, the amino acid of the GyrA found in the position equivalent to Ser-83 of E. coli was Gln instead of a Ser or Thr, the amino acids usually encountered in this position among Gram-negative bacteria. The results suggest that there is not a relationship between the presence of this Gln and the resistance to quinolones in S. maltophilia. We can conclude that, contrary to what has been described in other microorganisms, in these S. maltophilia isolates, the development of resistance to quinolones was not related to mutations in the QRDR of gyrA and parC genes. Thus, to our knowledge, this is the first report describing this phenomenon.200212523620
3042190.9991Aminoglycoside acetyltransferase 3-IV (aacC4) and hygromycin B 4-I phosphotransferase (hphB) in bacteria isolated from human and animal sources. Members of the family Enterobacteriaceae harboring an enzyme of the aminoglycoside acetyltransferase 3 class (AAC-3-IV) (apramycin and gentamicin resistance) and hygromycin B phosphotransferase 4 (HPH-4-I) (hygromycin B resistance) have been isolated from human clinical sources in Europe. A cluster of genes containing IS140, aacC4, and hphB was found in these strains. We demonstrate by Southern hybridization that this cluster is identical to the operon found in animals that also contains insertion sequences belonging to the ISO family. This provides another example of presumptive transfer of antibiotic resistance genes between bacteria of animal and human origin.19901963287