Molecular epidemiology of two genes encoding 3-N-aminoglycoside acetyltransferases AAC(3)I and AAC(3)II among gram-negative bacteria from a Spanish hospital. - Related Documents




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201101.0000Molecular epidemiology of two genes encoding 3-N-aminoglycoside acetyltransferases AAC(3)I and AAC(3)II among gram-negative bacteria from a Spanish hospital. The molecular epidemiology of the aacC1 and aacC2 genes, encoding 3-N-aminoglycoside acetyltransferases AAC(3)I and AAC(3)II, respectively, was studied by DNA-DNA hybridization. The sample included 315 gentamicin-resistant Gram-negative bacilli collected over a six-month period from patients attending a Spanish Hospital. The aminoglycoside resistance phenotype of these strains was also determined. The aacC1 probe hybridized with 39 strains, the aacC2 probe with 146 strains and both probes hybridized with 26 strains. The aacC1 gene was most frequently detected in Pseudomonas aeruginosa whereas the aacC2 gene was most frequently detected in enterobacteria and Acinetobacter spp. Strains harbouring aacC genes were isolated from both in- and outpatients with different infectious diseases, mainly urinary tract infections. As inferred from the results of Southern hybridization, both genes showed a wide horizontal dispersion among plasmids and bacteria.19938150069
201010.9998Epidemiological survey of genes encoding aminoglycoside phosphotransferases APH (3') I and APH (3') II using DNA probes. The epidemiological survey of APH (3') I and APH (3') II genes, at a time when the specific antibiotic pressure was very low, was carried out by DNA-DNA hybridization. The sample included 334 aminoglycoside resistant Gram-negative bacteria collected from patients of a General Hospital. Of these, 251 hybridized with the APH (3') I-probe and 19 with the APH (3') II-probe but only 190 strains showed high resistance levels (CIM greater than 64 micrograms/ml) for kanamycin, neomycin and paromomycin. These strains were isolated both from inpatients and outpatients with different infectious diseases. The APH (3') I-gene was dispersed among all the bacterial species and clinical specimens tested but the APH (3') II-gene was not found in Pseudomonas spp, Escherichia coli, Citrobacter freundii and Enterobacter cloacae, nor in infected catheters. Several plasmids of different sizes carrying APH (3') genes were detected among different bacteria. Plasmids along with transposable elements (the probes used in this work were developed from Tn906 and Tn5) and the high consumption of other antibiotics whose resistance is carried by these bacteria might be playing an important role in the maintenance and dispersion of APH (3') genes.19921328557
96820.9998Molecular analysis of antimicrobial resistance in gram-negative bacteria isolated from fish farms in Egypt. As little is known about antimicrobial resistance genes in fish farms, this study was conducted to monitor the incidence and prevalence of a wide range of antimicrobial resistance genes in Gram-negative bacteria isolated from water samples taken from fish farms in the northern part of Egypt. Ninety-one out of two hundred seventy-four (33.2%) non-repetitive isolates of Gram-negative bacteria showed multidrug resistance phenotypes and harbored at least one antimicrobial resistance gene. PCR and DNA sequencing results showed that 72 (26.3%) isolates contain tetracycline resistance genes and 19 (6.9%) isolates were positive for class 1 integrons with 12 different gene cassettes. The beta-lactamase-encoding genes were identified in 14 (5.1%) isolates. The plasmid-mediated quinolone resistance genes, qnr and aac(6')-Ib-cr, were identified in 16 (5.8%) and 3 (1.1%) isolates, respectively. Finally, the florphenicol resistance gene, floR, was identified in four (1.5%) isolates. To the best of our knowledge, this is the first report for molecular characterization of antimicrobial resistance in Gram-negative bacteria isolated from fish farms in Africa.201020145377
290630.9998The mef(A) gene predominates among seven macrolide resistance genes identified in gram-negative strains representing 13 genera, isolated from healthy Portuguese children. Of the 176 randomly selected, commensal, gram-negative bacteria isolated from healthy children with low exposure to antibiotics, 138 (78%) carried one or more of the seven macrolide resistance genes tested in this study. These isolates included 79 (91%) isolates from the oral cavity and 59 (66%) isolates from urine samples. The mef(A) gene, coding for an efflux protein, was found in 73 isolates (41%) and was the most frequently carried gene. The mef(A) gene could be transferred from the donors into a gram-positive E. faecalis recipient and a gram-negative Escherichia coli recipient. The erm(B) gene transferred and was maintained in the E. coli transconjugants but was found in 0 to 100% of the E. faecalis transconjugants tested, while the other five genes could be transferred only into the E. coli recipient. The individual macrolide resistance genes were identified in 3 to 12 new genera. Eight (10%) of the oral isolates and 30 (34%) of the urine isolates for which the MICs were 2 to >500 microg of erythromycin per ml did not hybridize with any of the seven genes and may carry novel macrolide resistance genes.200415328110
214640.9998Study of aminoglycoside resistance genes in enterococcus and salmonella strains isolated from ilam and milad hospitals, iran. BACKGROUND: Aminoglycosides are a group of antibiotics that have been widely used in the treatment of life-threatening infections of Gram-negative bacteria. OBJECTIVES: This study aimed to evaluate the frequency of aminoglycoside resistance genes in Enterococcus and Salmonella strains isolated from clinical samples by PCR. MATERIALS AND METHODS: In this study, 140 and 79 isolates of Enterococcus and Salmonella were collected, respectively. After phenotypic biochemical confirmation, 117 and 77 isolates were identified as Enterococcus and Salmonella, respectively. After the biochemical identification of the isolates, antibiotic susceptibility for screening of resistance was done using the Kirby-Bauer method for gentamicin, amikacin, kanamycin, tobramycin and netilmycin. DNA was extracted from resistant strains and the presence of acc (3)-Ia, aac (3')-Ib, acc (6)-IIa ,16SrRNA methylase genes (armA and rat) was detected by PCR amplification using special primers and positive controls. RESULTS: Enterococcus isolates have the highest prevalence of resistance to both kanamycin and amikacin (68.4%), and Salmonella isolates have the highest prevalence of resistance against kanamycin (6.9%). Ninety-three and 26 isolates of Enterococcus and Salmonella at least were resistant against one of the aminoglycosides, respectively. Moreover, 72.04%, 66.7%, and 36.6% of the resistant strains of Enterococcus had the aac (3')-Ia, aac (3')-IIa, and acc (6')-Ib genes, respectively. None of the Salmonella isolates have the studied aminoglycoside genes. CONCLUSIONS: Our results indicate that acetylation genes have an important role in aminoglycoside resistance of the Enterococcus isolates from clinical samples. Moreover, Salmonella strains indicate very low level of aminoglycoside resistance, and aminoglycoside resistance genes were not found in Salmonella isolates. These results indicate that other resistance mechanisms, including efflux pumps have an important role in aminoglycoside resistance of Salmonella.201526034551
89250.9997Sequencing analysis of tigecycline resistance among tigecycline non-susceptible in three species of G-ve bacteria isolated from clinical specimens in Baghdad. BACKGROUND: Recent emergence of high-level tigecycline resistance is mediated by tet(X) genes in Gram-negative bacteria, which undoubtedly constitutes a serious threat for public health worldwide. This study aims to identify tigecycline non-susceptible isolates and detect the presence of genes that are responsible for tigecycline resistance among local isolates in Iraq for the first time. METHODS: Thirteen clinical isolates of Klebsiella pneumonia, Acinetobacter baumannii and Pseudomonas aeruginosa tigecycline non-susceptible were investigated from blood, sputum and burns specimens. The susceptibility of different antibiotics was tested by the VITEK-2 system. To detect tigecycline resistance genes, PCR was employed. RESULTS: Strains studied in this work were extremely drug-resistant and they were resistant to most antibiotic classes that were studied. The plasmid-encoded tet(X), tet(X1), tet(X2), tet(X3), tet(X4), tet(X5), tet(M) and tet(O) genes were not detected in the 13 isolates. The results showed that there is a clear presence of tet(A) and tet(B) genes in tigecycline non-susceptible isolates. All 13 (100%) tigecycline non-susceptible K. pneumoniae, A. baumannii and P. aeruginosa isolates harbored the tet(B) gene. In contrast, 4 (30.77%) tigecycline non-susceptible P. aeruginosa isolates harbored the tet(A) gene and there was no tigecycline non-susceptible A. baumannii isolate harboring the tet(A) gene (0%), but one (7.69%) tigecycline non-susceptible K. pneumoniae isolate harbored the tet(A) gene. A phylogenetic tree, which is based on the nucleotide sequences of the tet(A) gene, showed that the sequence of the local isolate was 87% similar to the nucleotide sequences for all the isolates used for comparison from GenBank and the local isolate displayed genetic diversity. CONCLUSIONS: According to this study, tet(B) and tet(A) play an important role in the appearance of tigecycline non-susceptible Gram-negative isolates.202236207501
290760.9997Prevalence of tetracycline resistance genes and identification of tet(M) in clinical isolates of Escherichia coli from sick ducks in China. Tetracycline resistance is one of the most frequently encountered resistance properties in bacteria of animal origin. The aim of the present study was to investigate the prevalence and diversity of tetracycline resistance (tet) genes among Escherichia coli clinical isolates from diseased ducks in China and to report the identification and sequencing of the tet(M) gene. The susceptibility of 85 Escherichia coli strains to tetracyclines was determined by broth microdilution, and the presence of tet genes was investigated by multiplex PCR. All of the 85 isolates were fully resistant to both oxytetracycline and tetracycline, and 76.5 % were resistant to doxycycline. Seventy-seven of the isolates (90.6 %) encoded multiple tet genes, with 17.6, 38.8 and 34.1 % encoding two, three and four tet genes, respectively, and only 7.1 % encoded a single tet(A) gene. The MICs of oxytetracycline and tetracycline for all isolates ranged from 16 to ≥128 µg ml(-1) with a MIC90 of >128 µg ml(-1), regardless of the type or number of tet genes encoded. Isolates containing tet(M) commonly had more than one tet gene per strain. The doxycycline resistance rate in the tet(M)-positive isolates was significantly higher than in the tet(M)-negative isolates (P<0.05). A full-length tet(M) gene, including the promoter region, was obtained by PCR in seven of the 41 tet(M)-positive isolates and was sequenced and cloned. The cloned tet(M) gene conferred resistance to tetracyclines in the recombinant Escherichia coli host strain. These results revealed that, in these isolates, the prevalence of multiple tet genes was strikingly high and that tet(M) played a role in doxycycline resistance.201323475906
214770.9997Identification of Genes Coding Aminoglycoside Modifying Enzymes in E. coli of UTI Patients in India. This study is to probe the pattern of antibiotic resistance against aminoglycosides and its mechanism in E. coli obtained from patients from Chennai, India. Isolation and identification of pathogens were done on MacConkey agar. Antimicrobial sensitivity testing was done by disc diffusion test. The identification of genes encoding aminoglycoside modifying enzymes was done by Polymerase Chain Reaction (PCR). Out of 98 isolates, 71 (72.45%) isolates were identified as E. coli and the remaining 27 (27.55%) as other bacteria. Disc diffusion method results showed a resistance level of 72.15% for streptomycin, 73.4% for gentamicin, 63.26% for neomycin, 57.14% for tobramycin, 47.9% for netilmicin, and 8.16% for amikacin in E. coli. PCR screening showed the presence of four genes, namely, rrs, aacC2, aacA-aphD, and aphA3, in their plasmid DNA. The results point towards the novel mechanism of drug resistance in E. coli from UTI patients in India as they confirm the presence of genes encoding enzymes that cause resistance to aminoglycoside drugs. This could be an alarm for drug prescription to UTI patients.201627403451
202380.9997Class 1 and class 2 integrons and plasmid-mediated antibiotic resistance in coliforms isolated from ten rivers in northern Turkey. We aimed to determine the molecular mechanisms of antibiotic resistance in coliforms isolated from ten rivers in northern region of Turkey. A total of 183 isolates were tested for antimicrobial susceptibility by disk diffusion and agar dilution methods. Resistance to ampicillin, streptomycin, trimethoprim, tetracycline, and chloramphenicol was detected in 58%, 51.9%, 24%, 28.4%, and 12.5%, respectively. Twelve (6.5%) phylogenetically distant organisms were detected to harbor self-transmissible plasmids ranging 52 to >147 kb in sizes. Resistances to ampicillin, tetracycline, trimethoprim, streptomycin, and nalidixic acid were commonly transferable traits. Transferable nalidixic acid-resistant strains harbored qnrS gene, which was the first report of plasmid-mediated quinolone resistance in bacteria of environmental origin in Turkey. Fourteen and five coliforms harbored class 1 and class 2 integrons, respectively, and some of them were located on transferable plasmids. Sequence analyses of variable regions of the class 1 and 2 integrons harbored various gene cassettes, dfrA1, dfr2d, dfrA7, dfrA16, dfrA17, aadA1, aadA5, bla(oxA-30), and sat1. A gene cassette array, dfrA16 has been demonstrated for the first time in a Citrobacter koseri isolate. Class 1 and class 2-bearing strains were clustered in different groups by BOX-PCR fingerprinting. Rivers in the northern Turkey may act as receptacle for the multi-drug resistant enterobacteria and can serve as reservoirs of the antimicrobial resistance determinants in the environment. The actual risk to public health is the transfer of resistance genes from the environmental bacteria to human pathogens.200919229487
208190.9997Distribution 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
2055100.9997Prevalence and characterization of plasmid-mediated quinolone resistance genes in Salmonella isolated from poultry in Korea. The purpose of this study was to investigate the prevalence and characteristics of plasmid-mediated quinolone resistance (PMQR) genes qnr, aac(6')-Ib-cr, and qepA in a total of 185 non-duplicate Salmonella spp. isolated from hatcheries, poultry farms, and poultry slaughterhouses during the period 2001 to 2010 in Korea. Additionally, mutation analysis of quinolone resistance determining regions (QRDRs), conjugation experiments, and plasmid analysis were performed in the PMQR-positive isolates. Among the 185 isolates, six (3.2%) contained qnr genes (two qnrB4 and four qnrS1) but none carried the aac(6')-Ib-cr or qepA genes. Among the six PMQR-positive isolates, one showed a single mutation (Ser83-Phe substitution) in the QRDRs of gyrA. Among them, three were non-susceptible (intermediate or resistant) to nalidixic acid (minimum inhibitory concentration [MIC] ≥256 µg/ml), ciprofloxacin (MIC 2 µg/ml), and levofloxacin (MIC 4 µg/ml), but others were susceptible to all of the three fluoroquinolones. They were resistant to six or more antimicrobial agents tested and were able to transfer quinolone resistance to recipient Escherichia coli J53 by conjugation. By performing a hybridization test, plasmids harbouring qnrB4 and qnrS1 genes were less than 8 kb and about 70 kb in size, respectively. The horizontal dissemination of qnrS1 gene was mediated by IncN plasmid. Compared with the recipient strain, MICs of the transconjugants increased two-fold to four-fold for nalidixic acid, and eight-fold to 16-fold for ciprofloxacin and levofloxacin. This report is the first to describe the detection of qnr genes in Salmonella spp. isolated from poultry in Korea. Widespread horizontal transfer of these genes among bacteria may be a serious public health concern because these can rapidly increase fluoroquinolone resistance. To ensure the public health, it is essential to continuously survey and carefully monitor the spread of PMQR genes in Salmonella from poultry.201323607509
2913110.9997Distribution of resistance genetic determinants among Vibrio cholerae isolates of 2012 and 2013 outbreaks in IR Iran. The objective of this study was to characterize antimicrobial resistance determinants in relation to antimicrobial susceptibility and genotyping profile in 20 clinical isolates of Vibrio cholerae. All of the isolates were resistant to streptomycin. The second most prevalent resistance was observed to trimethoprim (75%), co-trimoxazole (60%), tetracycline (50%), and minocycline (45%). About 50% of the isolates fulfilled the criteria of Multi Drug Resistance (MDR) phenotype. None of the isolates carried tet A, B, C, and, D determinants. This finding shows that tetracycline resistance determinants recognized so far, does not satisfactorily describe the 50% tetracycline resistance phenotype in this study, suggesting the possible contribution of other not yet characterized resistance mechanisms involved. Class 1 integron, widely distributed among enteric bacteria, was not detected among V. cholerae strains under study. Conversely, 100% of the isolates harbored SXT constin((int)), among which 70% were positive for dfrA1, strA, and strB genes. The sul1gene was present in 60% of the isolates while none of them contained floR gene. All the isolates uniformly appeared to be identical in fingerprinting profiles expected from outbreak strains. In conclusion, SXT element with its mosaic structure was the exclusive antimicrobial resistance determinant of clonal V. cholerae isolates taken from outbreaks of 2012 and 2013 in Iran.201728062293
897120.9997Prevalence of class 1 integrons and plasmid-mediated qnr-genes among Enterobacter isolates obtained from hospitalized patients in Ahvaz, Iran. Quinolones are frequently used classes of antimicrobials in hospitals, crucial for the treatment of infections caused by Gram-negative bacteria. The inappropriate use of quinolones and other antimicrobial agents for the treatment of bacterial infections leads to a significant increase of resistant isolates. The acquisition of antimicrobial resistance may be related to achievement of resistance determinant genes mediated by plasmids, transposons and gene cassettes in integrons. The objective of this cross-sectional study, conducted from December 2015 to July 2016 at two teaching hospitals in Ahvaz, southern Iran, was to screen for the presence of class 1 integrons and quinolone resistance genes in clinical isolates of Enterobacter spp. In all, 152 non-duplicated Enterobacter isolates were collected from clinical specimens and identified as Enterobacter spp. using standard microbiological methods. Antimicrobial susceptibility test was determined using the disc diffusion method according to the CLSI recommendation. Determination of class 1 integrons and PMQR genes was assessed by PCR. Analysis of antibiotic susceptibility tests showed that the highest antibiotic resistance was toward ciprofloxacin (55.3%), while the lowest level was observed against meropenem (34.9%). Moreover, 47.4% (72/152) and 29% (44/152) of isolates were positive for class 1 integron and quinolone resistance genes, respectively. The relative frequencies of antibiotic resistance were significantly higher among class 1 integron-positive isolates. In summary, our results highlight the importance of PMQR genes in the emergence of quinolone-resistant Enterobacter isolates. Moreover, it seems that class 1 integrons have a widespread distribution among Enterobacter isolates and have clinical relevance to multiple-drug-resistant isolates.201729286015
1273130.9997Trimethoprim resistance in gram-negative bacteria isolated in South Africa. Resistance to trimethoprim was surveyed in 2914 Gram-negative bacteria isolated in three hospitals in South Africa. Bacteria were collected from November 1986 to January 1987 and the minimum inhibitory concentration (MIC) of trimethoprim for each isolate was determined. The overall resistance rate (MIC greater than 8 mg/l) was 56.2%, and high-level resistance (MIC greater than 1024 mg/l) occurred in 24.0% of the total. The frequency of resistance in isolates of Enterobacteriaceae was 48.5% (MIC greater than 8 mg/l). Of the organisms isolated from urine specimens, 49.1% were resistant to trimethoprim, 71.8% of these being highly resistant. Investigation of 36 isolates for the presence of the type I and/or type II dihydrofolate reductase genes showed that eight isolates reacted with the type I probe but none with the type II probe.19892621180
2054140.9997A survey of plasmid-mediated fluoroquinolone resistance genes from Escherichia coli isolates and their dissemination in Shandong, China. Bacterial resistance to fluoroquinolones result from mutations in the quinolone resistance-determining regions of the drug targets, overexpression of efflux pumps, and/or the more recently identified plasmid-mediated low-level resistance mechanisms. We investigated the prevalence of and characterized plasmid-mediated fluoroquinolone resistance genes (qnrA, qnrB, qnrS, aac(6')-Ib-cr, and qepA) by polymerase chain reaction in fluoroquinolone-resistant Escherichia coli (n = 530) isolated from a chicken farm, a pig farm, and hospitalized patients in Shandong, China, in 2007. The aac(6')-Ib-cr gene was the most prevalent resistance gene that was detected in bacteria isolated from all sources. Next was the qnrS gene, which was predominantly present in isolates from the pig farm. Only eight (5.8%) isolates from hospital patients were found to possess the qepA gene, and these isolates were first reported in qepA-carrying E. coli from humans in China. The qnrA and qnrB genes were not detected in any of the isolates. Further, most of the isolates were also resistant to beta-lactams and aminoglycosides as determined by the broth microdilution method. Pulsed-field gel electrophoresis analysis of the E. coli isolates with similar resistance patterns that also carried resistance genes showed great genomic diversity among these bacteria, suggesting that the multiresistant E. coli isolates carrying the qnr, aac(6')-Ib-cr, or qepA genes were not derived from a specific clone, but represented a wide variety of different genotypes. The results of Southern hybridization revealed that qepA, qnrS, and parts of aac(6')-Ib-cr genes were localized on plasmids and/or chromosome. qepA and aac(6')-Ib-cr genes were colocalized with aac(6')-Ib-cr and qnrS genes, respectively, on the same plasmids. Our study demonstrated that two different genes (qepA and aac(6')-Ib-cr) were identified on the same plasmid in E. coli strains derived from patients and qnrS and aac(6')-lb-cr genes on the same plasmid in an E. coli strain of animal origin.201019911944
2045150.9997Molecular characterization of multidrug-resistant Shigella species isolated from epidemic and endemic cases of shigellosis in India. Shigella species represent one of the growing numbers of antimicrobial-resistant bacteria in developing countries. Fluoroquinolone-resistant strains of Shigella dysenteriae type 1 and Shigella flexneri type 2a emerged in India during 2002 and 2003, respectively. Sixty strains of Shigella from different parts of India were analysed for antimicrobial susceptibility, the presence of the qnr plasmid, mutations in the quinolone resistance determining regions (QRDRs), fluoroquinolone accumulation, and the presence of other genes encoding resistance to various antimicrobials. Fluoroquinolone-resistant strains had mutations in gyrA and parC genes and had an active efflux system. They were also resistant to several other antimicrobials but were susceptible to azithromycin and ceftriaxone. The majority of the strains harboured genes encoding resistance to ampicillin (97 %), tetracycline (95 %), streptomycin (95 %) and chloramphenicol (94 %). PFGE analysis revealed clonality among strains of S. dysenteriae types 1 and 5, S. flexneri type 2a and Shigella boydii type 12.200818566144
2053160.9997Replicon typing of plasmids in environmental Achromobacter sp. producing quinolone-resistant determinants. This study aimed to investigate the antimicrobial resistance profile to quinolones, the presence of quinolone-resistant determinants and the plasmid replicon typing in environmental Achromobacter sp. isolated from Brazil. Soil and water samples were used for bacterial isolation. The antimicrobial susceptibility testing was performed by minimum inhibitory concentration method. The detection of mutations in the quinolone resistance-determining regions (QRDR) genes, the presence of plasmid-mediated quinolone resistance (PMQR) genes, and plasmid replicons were performed by PCR. A total of 16 isolates was obtained from different cultures, cities, and states of Brazil. All isolates were non-susceptible to ciprofloxacin, norfloxacin, and levofloxacin. Some mutations in QRDR genes were found, including Gln-83-Leu and Asp-87-Asn in the gyrA and Gln-80-Ile and Asp-84-Ala in the parC. Different PMQR genes were detected, such as qnrA, qnrB, qnrS, oqxA, and oqxB. Three different plasmid families were detected, being most presented the ColE-like, followed by IncFIB and IncA/C. The presence of different PMQR genes and plasmids in the isolates of the present study shows that environmental bacteria can act as reservoir of important genes of resistance to fluoroquinolones, which is of great concern, due to the potential of horizontal dissemination of these genes. Besides that, there are no studies reporting these results in Achromobacter sp. isolates.201830357960
2163170.9997Molecular epidemiology of aminoglycosides resistance in acinetobacter spp. With emergence of multidrug-resistant strains. BACKGROUND: Acinetobacter spp. is characterized as an important nosocomial pathogen and increasing antimicrobial resistance. Our aim was to evaluate antimicrobial susceptibility and aminoglycosides resistance genes of Acinetobacter spp. isolated from hospitalized patients. METHODS: Sixty isolates were identified as Acinetobacter species. The isolates were tested for antibiotic resistance by disc diffusion method for 12 antimicrobials. The presence of aphA6, aacC1 aadA1, and aadB genes were detected using PCR. RESULTS: From the isolated Acinetobacter spp. the highest resistance rate showed against amikacin, tobramycin, and ceftazidim, respectively; while isolated bacteria were more sensitive to ampicillic/subactam. More than 66% of the isolates were resistant to at least three classes of antibiotics, and 27.5% of MDR strains were resistant to all seven tested classes of antimicrobials. The higher MDR rate presented in bacteria isolated from the ICU and blood samples. More than 60% of the MDR bacteria were resistance to amikacin, ceftazidim, ciprofloxacin, piperacillin/tazobactam, doxycycline, tobramycin and levofloxacin. Also, more than 60% of the isolates contained phosphotransferase aphA6, and acetyltransferase genes aacC1, but adenylyltransferase genes aadA1 (41.7%), and aadB (3.3%) were less prominent. 21.7% of the strains contain three aminoglycoside resistance genes (aphA6, aacC1 and aadA1). CONCLUSION: The rising trend of resistance to aminoglycosides poses an alarming threat to treatment of such infections. The findings showed that clinical isolates of Acinetobacter spp. in our hospital carrying various kinds of aminoglycoside resistance genes.201023113008
2150180.9997Analysis of drug resistance genes of integrons in clinical isolates of Escherichia coli from elderly bloodstream infections. This experiment was carried out to provide a basis for the treatment of clinical bloodstream infections by analyzing the drug resistance characteristics and integrated gene distribution of Escherichia coli in bloodstream infections in elderly patients. For this aim, E. coli were collected for bacterial identification and drug sensitivity testing from bloodstream infections in elderly patients in the hospital from January 2016 to December 2019. ESBLs positive strains were assayed for genotypes and their integron carriage rates by PCR amplification. The characteristics and differences of various genotype rates were compared and analyzed. Results showed that a total of 230 E. coli strains were isolated. The detection rate of ESBLs-producing bacteria was 37.39 %. ESBLs-producing E. coli showed a high rate of resistance to cefepime, levofloxacin, cotrimoxazole, and ticarcillin/clavulanic acid (>40%). The resistance rate of 230 strains of E. coli to meropenem, minocycline, amikacin, gentamicin and cefoxitin was less than 20%. Among the ESBLs-producing E. coli in bloodstream infections in elderly patients, CTX-M-9 accounted for 27.91%, CTX-M-2 for 17.44%, and SHV for 13.95%. The detection rate of type I integrated genes was 41.30%, and type II and III integrated genes were not detected. ESBLs-producing genotyping-positive bacteria were detected with more than 50% of type I integrated genes. It was concluded that type I integrated genes in ESBLs-producing E. coli isolated from elderly patients carried resistance genes such as CTX-M-9 and CTX-M-2 aggravating multi-drug resistance in bacteria.202236227675
965190.9997Molecular Characterization of Multidrug-Resistant Escherichia coli Isolates from Bovine Clinical Mastitis and Pigs in the Vojvodina Province, Serbia. The aim of the study was to characterize multidrug-resistant (MDR) Escherichia coli isolates collected in Serbia from bovine clinical mastitis cases and diseased pigs, mainly with molecular methods. A total of 48 E. coli isolates was collected during the years 2013-2014, of which 22 were MDR and were included in further analysis. Phylogenetic typing showed that 17 isolates belonged to group A, while two isolates were classified in group B1 and a single one in group D. All isolates showed unique macrorestriction patterns. Phenotypic susceptibility testing revealed resistances of the isolates against up to 13 antimicrobial agents, including resistance to fluoroquinolones. A wide variety of resistance genes was detected by PCR amplification and sequencing of amplicons. Sequence analysis of the quinolone resistance determining regions of topoisomerase genes revealed mutations in gyrA, parC, and/or parE. Plasmid-mediated quinolone resistance genes were detected in two porcine (aac-6'-Ib-cr and qnrS, respectively) isolates and a single bovine (aac-6'-Ib-cr) isolate. Resistance genes were found to be located on conjugative plasmids in 16 cases, many of which conferred a multidrug resistance phenotype. In conclusion, the plentitude of resistance genes located on conjugative plasmids and integrons in E. coli from cows and pigs in Vojvodina, Serbia, pose a high risk for horizontal gene transfer in bacteria from livestock husbandry.201828520501