Resistance carrying plasmid in a traumatic wound. - Related Documents




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206101.0000Resistance carrying plasmid in a traumatic wound. OBJECTIVE: To isolate and identify antibiotic-resistant bacteria from the exudate of a complex wound and determine if antibiotic resistance genes are chromosomal or plasmid borne. METHOD: Antibiotic resistant bacteria from wound exudate of a single clinical sample were selected on agar media with ampicillin. A single colony was further screened for resistance to kanamycin by antibiotic-supplemented agar and to other antibiotics by an automated Phoenix instrument. Identification of the isolate was carried out by biochemical profiling and by 16S rDNA analysis. RESULTS: Approximately 51% of total bacteria in the wound exudate with identical colony morphotype were resistant to 100 microg/ml of ampicillin. A single colony from this population also demonstrated resistance to 50 microg/ml of kanamycin on kanamycin-supplemented agar. Further antimicrobial sensitivity testing by the Phoenix instrument indicated resistance to inhibitory concentrations of amoxicillin-clavulanate, ampicillin-sulbactam, cefazolin, gentamicin, nitrofurantoin, tobramycin, and trimethoprim-sulfamethoxazole. Biochemical and 16S rDNA analysis identified this bacterial isolate as a member of genus Enterobacter. A plasmid preparation from this isolate successfully transferred ampicillin and kanamycin resistance to E. coli competent cells. E. coli transformants displayed two resistance phenotypes and the plasmids from these transformants displayed two different restriction type patterns, with one correlating to ampicillin and kanamycin resistance and the other only to ampicillin resistance. CONCLUSION: A multiple antibiotic-resistant Enterobacter spp. from the wound fluid of a clinical sample was found to carry an antibiotic-resistant plasmid in a closely related species E. coli. The presence of antibiotic resistance plasmid in Enterobacteria that are part of the normal microbial flora of the human gut and skin could lead to the spread of resistance phenotype and emergence of antibiotic resistant pathogens. This study suggests normal human microbial fl ora could be a potential reservoir for resistance genes.201020616773
206010.9998Plasmid-mediated high-level gentamicin resistance among enteric bacteria isolated from pet turtles in Louisiana. The sale of small turtles is banned by the Food and Drug Administration from the U.S. market due to concerns about their excretion of Salmonella spp. To produce a safe pet for the export market, the Louisiana pet turtle industry uses gentamicin sulfate baths (1,000 microg/ml) to eradicate Salmonella spp. from turtle eggs. In 1999, we analyzed bacterial samples recovered from turtle farms and found that strains of Salmonella enterica subsp. arizonae and other bacteria, such as Enterobacter cloacae, Citrobacter freundii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia, were resistant to high concentrations of gentamicin (>2,000 microg/ml) and to other aminoglycosides. The goal of this study was to identify the gene(s) which contributes to the high-level gentamicin resistance phenotype observed in bacteria from environmental samples with turtle farming activity, particularly the salmonellae, and to estimate the incidence of such genes in these bacteria. R plasmids from gentamicin-resistant strains were transferred by conjugation and transformation to naive Escherichia coli cells. Cloning and sequencing of the gentamicin resistance determinants on these plasmids revealed the presence of the aminoglycoside acetyltransferase genes aac(3)-IIa and aac(3)-VIa; the latter was present as a gene cassette of a class 1 integron. Multiplex PCR assays showed that every gentamicin-resistant isolate carried one of these acetyltransferase genes. Pulsed-field gel electrophoresis and restriction enzyme digestion analysis of R plasmids carrying these genes revealed different restriction profiles and sizes, indicating a dissemination of the gentamicin resistance genes through mobile molecular elements. The data presented highlight the need to develop an alternate method for the eradication of Salmonella spp. from turtle eggs.200616391058
554920.9998Analysis of Antibiotic Resistance and Biofilm-Forming Capacity in Tetracycline-Resistant Bacteria from a Coastal Lagoon. Concerns have been raised regarding co-selection for antibiotic resistance among bacteria exposed to antibiotics used as growth promoters for some livestock and poultry species. Tetracycline had been commonly used for this purpose worldwide, and its residue has been associated with selection of resistant bacteria in aquatic biofilms. This study aimed to determine the resistance profile, the existence of some beta-lactamases genes and the capacity to form biofilm of bacteria isolated from water samples previously exposed to tetracycline (20 mg/L). Thirty-seven tetracycline-resistant bacterial strains were identified as Serratia marcescens, Escherichia coli, Morganella morganii, Pseudomonas aeruginosa, Citrobacter freundii, Providencia alcalifaciens, and Enterococcus faecium. The highest percentage of resistance was for ampicillin (75.75%) and amoxicillin/clavulanic acid (66.66%) in the Gram-negative bacteria and an E. faecium strain showed high resistance to vancomycin (minimum inhibitory concentration 250 μg/mL). Among the strains analyzed, 81.09% had multidrug resistance and eight Gram-negatives carried the bla(OXA-48) gene. All strains were able to form biofilm and 43.23% were strong biofilm formers. This study suggests that resistant bacteria can be selected under selection pressure of tetracycline, and that these bacteria could contribute to the maintenance and spread of antimicrobial resistance in this environment.202235325574
363230.9998Multiple antibiotic resistance among gram negative bacteria isolated from poultry. Gram negative bacteria, including species of Salmonella, Escherichia, Pseudomonas and Klebsiella, isolated from poultry, were screened for their resistance to the commonly used antibiotics: ampicillin, chloramphenicol, gentamycin, kanamycin, neomycin, polymyxin B, streptomycin and tetracycline. Of the 500 bacteria screened, 351 were found to be resistant to one or more antibiotics at the level of 50 micrograms/ml. Various patterns of antibiotic resistance observed during these studies have been reported.19948070844
592240.9998Incidence of infectious drug resistance among lactose-fermenting bacteria isolated from raw and treated sewage. Raw and treated sewage samples were examined for antibiotic-resistant, lactose-fermenting bacteria. Approximately 1% of the total lactose-fermenting bacteria were multiply resistant. Of these organisms, 50% were capable of transferring all or part of their resistance to a drug-sensitive recipient. Only 43% of those isolated on media containing a single antibiotic were capable of resistance transfer, whereas 57% of those recovered on multiple antibiotic plates transferred resistance. R factors conferring resistance to chloramphenicol, streptomycin, and tetracycline; streptomycin and tetracycline; and ampicillin, streptomycin, and tetracycline accounted for 22, 19, and 15%, respectively, of those identified. The data indicate a significant level of infectious drug resistance among the intestinal bacteria of the urban population.19695370461
554850.9998Prevalence of Antimicrobial Resistance Among the Hydrogen Sulfide Producing Bacteria Isolated on XLD Agar from the Poultry Fecal Samples. Poultry products remain as one of the most popular and extensively consumed foods in the world and the introduction of hydrogen sulfide (H(2)S) producing antibiotic resistant bacterial species into it is an emerging challenge. The current study has been designed to analyze the distribution of antibiotic resistance among the H(2)S producing bacteria isolated from the fecal samples of chickens from different poultry farms. Here, twenty bacterial isolates were selected based on their ability to produce H(2)S on XLD agar, and the16S rDNA sequencing was carried out for their molecular identification. The results showed the isolates as belong to Salmonella spp. and Citrobacter spp. and in the antibiotic susceptibility test (AST), three of the Salmonella strains were found to be resistant to antibiotics such as tetracycline, doxycycline, nalidixic acid, and amikacin. Also, fourteen Citrobacter strains showed resistance towards azithromycin, and furthermore, eleven of them were also resistant to streptomycin. Resistance towards tetracycline was observed among five of the Citrobacter strains, and seven were resistant to doxycycline. Further molecular screening by the PCR has showed three of the Salmonella strains along with eight Citrobacter isolates to have tetA gene along with four of the Citrobacter strains to have co-harbored bla(TEM) gene. The results on biofilm formation have also demonstrated three Salmonella strains along with nine Citrobacter strains to have the ability to form moderate biofilm. The study thus describes the occurrence of H(2)S producing multidrug-resistant bacteria in poultry feces, which might contribute towards the dissemination of antibiotic resistance genes to other microorganisms including human pathogens with likely risk to treat disease conditions.202437540287
238960.9998Antibiotic Resistance of LACTOBACILLUS Strains. The study provides phenotypic and molecular analyses of the antibiotic resistance in 20 Lactobacillus strains including 11 strains newly isolated from fermented plant material. According to the results of disc diffusion method, 90% of tested lactobacilli demonstrated sensitivity to clindamycin and 95% of strains were susceptible to tetracycline, erythromycin, and rifampicin. Ampicillin and chloramphenicol were found to inhibit all bacteria used in this study. The vast majority of tested strains revealed phenotypic resistance to vancomycin, ciprofloxacin, and aminoglycosides. Most of Lactobacillus strains showed high minimum inhibitory concentrations (MICs) of cefotaxime, ceftriaxone, and cefazolin and therefore were considered resistant to cephalosporins. All the strains exhibited multidrug resistance. The occurrence of resistance genes was associated with phenotypic resistance, with the exception of phenotypically susceptible strains that contained genes for tetracycline (tetK, tetL) and erythromycin (ermB, mefA) resistance. The vanX gene for vancomycin resistance was among the most frequently identified among the lactobacilli (75% of strains), but the occurrence of the parC gene for ciprofloxacin resistance was sporadic (20% of strains). Our results mainly evidence the intrinsic nature of the resistance to aminoglycosides in lactobacilli, though genes for enzymatic modification of streptomycin aadA and aadE were found in 20% of tested strains. The occurrence of extended spectrum beta-lactamases (ESBL) was unknown in Lactobacillus, but our results revealed the blaTEM gene in 80% of strains, whereas blaSHV and blaOXA-1 genes were less frequent (20% and 15% of strains, respectively).201931555856
269670.9998Carriage of antimicrobial resistant Escherichia coli in adult intestinal flora. Knowledge of antibiotic resistance in bacteria strains colonizing healthy people is important for several reasons, one of which is that; these organisms form one of the largest reservoirs of resistant genes. Frequency of resistance to eleven different antimicrobial agents was examined in faecal flora of adults with no history of recent antimicrobial treatment. Using the disc diffusion sensitivity test, 106 strains of Escherichia coli were examined, 68% of these were resistant to tetracycline, and 57% were resistant to ampicillin and cotrimoxazole respectively. There was no resistance to cefuroxime but resistance to ceftazidime was 13%. Fifty six out of the eighty eight (64%) isolates, which showed any resistance, were resistant to three or more antimicrobials. The most common resistant pattern was to three drugs tetracycline, ampicillin and cotrimoxazole. Six strains were susceptible to all antibiotics. One strain of Escherichia coli was resistant to eight antimicrobials. Thirty per cent of the Escherichia coli were resistant to gentamicin. This study reveals a high prevalence of resistant bacteria in faecal flora of healthy adults.200212081343
232780.9998Identification of Quinolone and Colistin Resistance Genes in Escherichia Coli Strains Isolated from Mucosal Samples of Patients with Colorectal Cancer and Healthy Subjects. INTRODUCTION: Antibiotic resistance and extensive use of antibiotics are amongst the major causes of failure in antibiotic treatment. The purpose of this study was to investigate antibiotic resistance patterns and to identify resistance genes of quinolones and colistin in Escherichia coli. There are a very few patents on E. coli isolated from colorectal cancer. So, this study demonstrates that some bacteria resistant to ciprofloxacin have not resistance genes.Moreover, new patterns for E. coli are presented for isolates of patients with colorectal cancer. MATERIALS AND METHODS: Of the three healthy people, inflammatory bowel diseases (IBD) patients and colorectal cancer patients, 40 E. coli strains isolated after confirmation by biochemical and molecular methods. The susceptibility of isolates to antibiotics was investigated using disk diffusion test. After deoxyribonucleic acid (DNA) extraction, polymerase chain reaction (PCR) was used to identify genes encoding resistance to ciprofloxacin (qnr A, qnr B) and colistin (mcr-1). RESULTS: The results showed that E. coli isolates from colorectal cancer patients had the highest resistance to piperacillin (67.5%), ceftazidime (47.5%), and cefepime (42.5%). Also, E. coli strains isolated from IBD patients showed resistance to antibiotic ceftazidime 13%. More than 95% of E. coli strains isolated from healthy people were susceptible to antibiotics. Based on the results, 18 (15%) E. coli strains showed resistance to ciprofloxacin. The qnr A gene was detected in 61.11% isolates; however, qnr B was detected in 9 (50%) isolates. Isolates resistant to colistin were not observed. CONCLUSION: These findings indicate increased resistance of E. coli to ciprofloxacin in comparison with prior studies. Further research in this field will increase our knowledge and more effective exposure to the antibiotic resistance of the pathogenic microorganisms.202031198116
206390.9998Nalidixic acid-a good marker of fluoroquinolone resistance mechanisms in Escherichia coli. The purpose of this study was to evaluate how ciprofloxacin, pefloxacin, and nalidixic acid disks perform in screening fluoroquinolone resistance mechanisms in 278 Escherichia coli isolates collected from a prospective clinical material. Antimicrobial susceptibility testing of ciprofloxacin, pefloxacin, and nalidixic acid was performed with the disk diffusion method. PCR-based and sequencing methods were used to detect chromosomal mutations in the gyrA and parC genes and the presence of plasmid-mediated qnr and aac(6')-1b-cr genes. In addition, whole-genome sequencing was used to confirm these results. Our results show that fluoroquinolone resistance mechanisms were discovered, even in ciprofloxacin-susceptible isolates, and plasmid-mediated low-level fluoroquinolone resistance is easily missed if only ciprofloxacin disk is used. E. coli strains with chromosomal gyrA and/or parC mutations were well detected with pefloxacin disk. However, nalidixic acid was a superior tool to detect and differentiate between low- (plasmid-mediated) and high-level (chromosomal mutations) fluoroquinolone resistance in E. coli. Thus, more clinical studies are needed to evaluate the clinical relevance of fluoroquinolone resistance mechanisms in enteric bacteria and pathogens that show potential but are not yet phenotypically fluoroquinolone-resistant. IMPORTANCE: We show in our clinical setting that fluoroquinolone resistance mechanisms are discovered, even among phenotypically fluoroquinolone-susceptible Escherichia coli isolates. When plasmid-mediated quinolone-resistance determinants are present, they are a potential risk for treatment failures due to accumulation of resistance mechanisms during the antimicrobial treatment. Therefore, when it is clinically relevant, fluoroquinolone resistance mechanisms in E. coli should be monitored more closely, and we also recommend testing nalidixic acid susceptibility.202540401973
5534100.9998Antibiotic resistance in faecal microbiota of Greek healthy infants. Increasing use of antibiotics for the treatment of infectious diseases and also for non-therapeutic reasons (agriculture, animal husbandry and aquaculture) has led to the increasing incidence of antibiotic resistance and the ineffectiveness of antimicrobial treatment. Commensal intestinal bacteria are very often exposed to the selective pressure of antimicrobial agents and may constitute a reservoir of antibiotic resistance determinants that can be transferred to pathogens. The present study aimed to investigate the antibiotic susceptibility profile and the presence of selected resistance genes in cocci isolated from the faecal microbiota of 35 healthy, full-term infants at 4, 30 and 90 days after delivery. A total of 148 gram-positive, catalase-negative cocci were isolated and tested for susceptibility to 12 different antibiotics by disk-diffusion technique. Multiplex PCR analysis was performed for the identification of Enterococcus spp. isolates and the simultaneous detection of vancomycin-resistance genes. PCR-based methodology was used also for identification of tetracycline and erythromycin resistance determinants. Identification results indicated E. faecalis as the predominant species (81 strains), followed by E. faecium, E. casseliflavus/E. flavescens and E. gallinarum. High prevalence of resistance to tetracycline (39.9%), erythromycin (35.1%), vancomycin (19.6%) and to nucleic acid synthesis inhibitors was detected. PCR data revealed 24 out of 52 erythromycin-resistant isolates carrying the ermB gene and 32 out of 59 tetracycline-resistant strains carrying tet genes, with tet(L) determinant being the most frequently detected. Only intrinsic vancomycin resistance (vanC1 and vanC2/C3) was reported among tested isolates. In conclusion, erythromycin and tetracycline acquired resistant traits are widespread among faecal cocci isolates from Greek, healthy infants under no apparent antimicrobial selective pressure.201021831766
5920110.9998Study on acquisition of bacterial antibiotic resistance determinants in poultry litter. Antibiotic resistance and the mode of transmission were investigated in bacteria isolated from poultry litter. Total aerobic heterotrophic bacteria were screened and identified for their resistance to different antibiotics such as ampicillin, streptomycin, erythromycin, tetracycline, chloramphenicol, kanamycin, tobramycin, and rifampicin. The distribution of bacteria found in the litter was Staphylococcus (29.1%), which was the predominant group, followed by Streptococcus (25%), Micrococcus (20.8%), Escherichia coli (12.5%), Salmonella (8.3%), and Aeromonas (4.1%). Fifty percent of these isolates were susceptible to ampicillin, 57% to erythromycin, 25% to tetracycline, 4% to chloramphenicol, 40% to kanamycin, 75% to streptomycin, 54% to tobramycin, and 4% to rifampicin. Three randomly selected isolates representing Staphylococcus, Streptococcus, and Micrococcus were examined for plasmids, and plasmid-curing and plasmid-induced transformation studies were conducted. Streptococcus and Micrococcus harbored a plasmid of 4.2 and 5.1 kb, respectively, whereas Staphylococcus did not harbor any plasmids. Plasmids were cured in Streptococcus and Micrococcus at a concentration of 75 and 100 microg/ mL of acridine orange, respectively, and transformation of 4.2- and 5.1-kb plasmids isolated from the Streptococcus and Micrococcus to plasmid-free E. coli DH5alpha strain was possible. In conjugation experiments, the antibiotic resistance profiles of transconjugant cells were found to be the same as the donors with the exception of Staphylococcus. The results of this study suggest that transformation and conjugation could be an important mechanism for horizontal gene transfer between bacteria in poultry litter. An understanding of the mechanism and magnitude of resistance gene transfer may provide a strategy to reduce the potential for dissemination of these genes.200919531707
5921120.9998Prevalence of tetracycline resistance genes in oral bacteria. Tetracycline is a broad-spectrum antibiotic used in humans, animals, and aquaculture; therefore, many bacteria from different ecosystems are exposed to this antibiotic. In order to determine the genetic basis for resistance to tetracycline in bacteria from the oral cavity, saliva and dental plaque samples were obtained from 20 healthy adults who had not taken antibiotics during the previous 3 months. The samples were screened for the presence of bacteria resistant to tetracycline, and the tetracycline resistance genes in these isolates were identified by multiplex PCR and DNA sequencing. Tetracycline-resistant bacteria constituted an average of 11% of the total cultivable oral microflora. A representative 105 tetracycline-resistant isolates from the 20 samples were investigated; most of the isolates carried tetracycline resistance genes encoding a ribosomal protection protein. The most common tet gene identified was tet(M), which was found in 79% of all the isolates. The second most common gene identified was tet(W), which was found in 21% of all the isolates, followed by tet(O) and tet(Q) (10.5 and 9.5% of the isolates, respectively) and then tet(S) (2.8% of the isolates). Tetracycline resistance genes encoding an efflux protein were detected in 4.8% of all the tetracycline-resistant isolates; 2.8% of the isolates had tet(L) and 1% carried tet(A) and tet(K) each. The results have shown that a variety of tetracycline resistance genes are present in the oral microflora of healthy adults. This is the first report of tet(W) in oral bacteria and the first report to show that tet(O), tet(Q), tet(A), and tet(S) can be found in some oral species.200312604515
5553130.9998Detection of class 1 integrons in Salmonella Weltevreden and silent antibiotic resistance genes in some seafood-associated nontyphoidal isolates of Salmonella in south-west coast of India. AIMS: To study the antibiogram of 40 seafood isolates of Salmonella and use of PCR to detect the presence of integrons and genes coding for antibiotic resistance. METHODS AND RESULTS: In this study, 40 isolates of Salmonella were used for antibiogram analysis. The multidrug-resistant isolates were analyzed for the presence of integron using integron-specific primers. Twenty-five percentage of the isolates were multidrug resistant while 67·50% were resistant to at least two antibiotics. Antibiotic resistance genes catA1 and tetA were present in 57·52 and 60%, respectively. Although widespread presence of genes was observed, only 26·08% of the catA1-carrying isolates exhibited phenotypic resistance against the respective antibiotic. Integrons present in representative isolates of Salmonella Weltevreden and Salmonella Newport were sequenced. The former contained class 1 integron with a single gene dfrA7 in the integron cassette and an adjacent dihydropteroate synthetase gene along with the usual quaternary ammonium compound resistance gene, while the later contained class 1 integron with dhfrA1, OrfC, in the integron cassette and an adjacent dihydropteroate synthetase gene along with the usual quaternary ammonium compound resistance gene. CONCLUSIONS: This study demonstrates the presence of silent antibiotic resistance genes and class I integrons in seafood-associated Salmonella strains. The study also demonstrates the first report of class I integron in Salm. Weltevreden. Detection of catA1 genes in phenotypically sensitive bacteria suggests that these could be reservoirs in the environment. SIGNIFICANCE AND IMPACT OF THE STUDY: The manuscript provides novel results describing the existence of a high rate of antibiotic resistance in the Salmonella populations prevailing in environmental sources as well as an absence of correspondence between the presence of antibiotic resistance genes, and the exhibition of a the corresponding phenotypic trait of resistance against the respective antibiotic compound was observed. In addition, the manuscript reports the presence of the class I integron in Salm. Weltevreden.201222443444
5538140.9998Phenotypic and genotypic antimicrobial susceptibility pattern of Streptococcus spp. isolated from cases of clinical mastitis in dairy cattle in Poland. Mastitis of dairy cattle is one of the most frequently diagnosed diseases worldwide. The main etiological agents of mastitis are bacteria of the genus Streptococcus spp., in which several antibiotic resistance mechanisms have been identified. However, detailed studies addressing this problem have not been conducted in northeastern Poland. Therefore, the aim of our study was to analyze, on phenotypic and genotypic levels, the antibiotic resistance pattern of Streptococcus spp. isolated from clinical cases of mastitis from dairy cattle in this region of Poland. The research was conducted using 135 strains of Streptococcus (Streptococcus uberis, n = 53; Streptococcus dysgalactiae, n = 41; Streptococcus agalactiae, n = 27; other streptococci, n = 14). The investigation of the antimicrobial susceptibility to 8 active substances applied in therapy in the analyzed region, as well as a selected bacteriocin (nisin), was performed using the minimum inhibitory concentration method. The presence of selected resistance genes (n = 14) was determined via PCR. We also investigated the correlation between the presence of resistance genes and the antimicrobial susceptibility of the examined strains in vitro. The highest observed resistance of Streptococcus spp. was toward gentamicin, kanamycin, and tetracycline, whereas the highest susceptibility occurred toward penicillin, enrofloxacin, and marbofloxacin. Additionally, the tested bacteriocin showed high efficacy. The presence of 13 analyzed resistance genes was observed in the examined strains [gene mef(A) was not detected]. In most strains, at least one resistance gene, mainly responsible for resistance to tetracyclines [tet(M), tet(K), tet(L)], was observed. However, a relationship between the presence of a given resistance gene and antimicrobial susceptibility on the phenotypic level was not always observed.201728601447
5955150.9998Integrons and gene cassettes in clinical isolates of co-trimoxazole-resistant Gram-negative bacteria. Despite a trend of declining consumption, resistance to co-trimoxazole has increased during a 12-year period in Stockholm. The molecular background to this surprising development was investigated by using PCR to screen for integrons and specific resistance genes, followed by sequence analysis of selected integrons, in 105 clinical urinary isolates of Gram-negative bacteria selected partly for trimethoprim resistance. Sixty-five integrons of class 1 or 2 were detected in a subset of 59 isolates, and of these positive isolates, all but one were resistant to trimethoprim. However, 11 isolates were resistant to trimethoprim, but negative for integrons. Isolates positive for integrons were resistant to an average of 4.2 antibiotics, compared with 1.9 antibiotics for integron-negative isolates. Despite this, the only gene cassettes identified in 19 class 1 integrons analysed were dfr and aadA cassettes. Thus, only resistance to trimethoprim, streptomycin, spectinomycin and sulphonamides could be explained by the presence of integrons in these isolates. A new dfr gene, named dfrA22, was discovered as a single gene cassette in a class 1 integron. In addition, sulphonamide resistance in many isolates was caused by carriage of sul2, which has no known association with integrons. Resistance to co-trimoxazole and many other antibiotics was thus not accounted for fully by the presence of integrons in these isolates.200515715715
5938160.9998Characterization of Mechanisms Lowering Susceptibility to Flumequine among Bacteria Isolated from Chilean Salmonid Farms. Despite their great importance for human therapy, quinolones are still used in Chilean salmon farming, with flumequine and oxolinic acid currently approved for use in this industry. The aim of this study was to improve our knowledge of the mechanisms conferring low susceptibility or resistance to quinolones among bacteria recovered from Chilean salmon farms. Sixty-five isolates exhibiting resistance, reduced susceptibility, or susceptibility to flumequine recovered from salmon farms were identified by their 16S rRNA genes, detecting a high predominance of species belonging to the Pseudomonas genus (52%). The minimum inhibitory concentrations (MIC) of flumequine in the absence and presence of the efflux pump inhibitor (EPI) Phe-Arg-β-naphthylamide and resistance patterns of isolates were determined by a microdilution broth and disk diffusion assays, respectively, observing MIC values ranging from 0.25 to >64 µg/mL and a high level of multi-resistance (96%), mostly showing resistance to florfenicol and oxytetracycline. Furthermore, mechanisms conferring low susceptibility to quinolones mediated by efflux pump activity, quinolone target mutations, or horizontally acquired resistance genes (qepA, oqxA, aac(6')-lb-cr, qnr) were investigated. Among isolates exhibiting resistance to flumequine (≥16 µg/mL), the occurrence of chromosomal mutations in target protein GyrA appears to be unusual (three out of 15), contrasting with the high incidence of mutations in GyrB (14 out of 17). Bacterial isolates showing resistance or reduced susceptibility to quinolones mediated by efflux pumps appear to be highly prevalent (49 isolates, 75%), thus suggesting a major role of intrinsic resistance mediated by active efflux.201931847389
5550170.9998Prevalence, plasmids and antibiotic resistance correlation of enteric bacteria in different drinking water resources in sohag, egypt. BACKGROUND: One of the major health causing problems is contamination of drinking water sources with human pathogenic bacteria. Enteric bacteria such as Shigella, Salmonella and Escherichia coli are most enteric bacteria causing serious health problems. Occurrence of such bacteria infection, which may resist antibiotics, increases the seriousness of problem. OBJECTIVES: The aim of this study was to examine the prevalence of some enteric bacteria (Shigella, Salmonella and E. coli) in addition to Pseudomonas. The antibiotic susceptibility of these bacteria was also tested, in addition to assessing plasmid(s) roles in supposed resistance. MRSA genes in non-staphylococci were clarified. MATERIALS AND METHODS: Water samples were collected from different drinking sources (Nile, ground water) and treated tap water. Selective media were used to isolate enteric bacteria and Pseudomonas. These bacteria were identified, counted and examined for its susceptibility against 10 antibiotics. The plasmids were screened in these strains. MRSA genes were also examined using PCR. RESULTS: Thirty-two bacterial strains were isolated from Nile and ground water and identified as S. flexneri, S. sonnei, S. serovar Newport, Pseudomonas aeruginosa and E. coli strains according to standard methods. According to antibiotic susceptibility test, 81% of strains were resistant to Cefepime, whereas 93.75% were sensitive to Ciprofloxacin. Correlation analysis between plasmids profiles and antibiotics sensitivities showed that 50% of the total strains had plasmids. These strains showed resistance to 50% of the used antibiotics (as average value); whereas, the plasmids free strains (50%) were resistant to 48.7% of the antibiotics. No distinct correlation between plasmids and antibiotic resistance in some strains could be concluded in this study. No MRSA gene was detected among these non-staphylococci strains. No bacteria were isolated from treated tap water. CONCLUSIONS: Thirty-three bacterial strains; 10 strains of E. coli, 10 strains of S. flexneri, 3 strains S. sonnei, 2 strains of S. serovar Newport, and 7 strains of P. aeruginosa, were isolated and identified from Nile water and ground water in Sohag governorate. The prevalence of enteric bacteria in water sources in studying area was considerable. No clear or distinct correlation could be concluded between plasmids and antibiotic resistance. No MRSA gene was detected in these non-staphylococci strains, and no pathogenic bacteria were isolated from treated tap water. The hygiene procedures in the studying area seem to be adequate, despite the failure to maintain water sources form sewage pollution.201525763135
2915180.9998Detection of class 1 integron-associated gene cassettes and tetracycline resistance genes in Escherichia coli isolated from ready to eat vegetables. BACKGROUND: Ready to eat (RTE) vegetables are easily accessible healthy foods that are commonly consumed globally, including in Indonesia. However, these RTE vegetables contain potential contamination from pathogens and multi-drug resistant bacteria. Therefore, in the present study, we examined the presence of tetracycline-resistant E. coli (TRE) isolates from RTE vegetables. METHODS: Susceptibility to antimicrobial agents was determined using the Kirby-Bauer disc diffusion method. Characterisation of antibiotic resistant genes was performed using PCR and sequencing of tetracycline resistant gene, integron and gene cassette from the TRE isolates. RESULTS: The isolates collected in this study were resistant not only to tetracycline, but also to streptomycin. Some isolates also displayed resistance to kanamycin (77.8%), chloramphenicol (11.1%), and ciprofloxacin (5.6%). All of the isolates contained integrons (intI1) and the tetA gene; tetB was not detected in our study. Further analysis showed that some isolates (38.8%) contained the dfrA7 gene cassette, which encodes dihydrofolate reductase, which is responsible for resistance to trimethoprim. Of all the isolates that presented integrons, 11 isolates (61.1%) did not carry gene cassettes. These empty integrons have the potential to convert themselves rapidly into multigraviton strains. CONCLUSIONS: TRE isolates contain the tetA gene and integron 1. Only 38.8% of the isolates that have been identified contain the dfrA7 gene cassette, which is responsible for trimethoprim antibiotic resistance. Further identification of genes conferring resistance to other antibiotics is necessary to better characterise antibiotic resistance.202032566218
2909190.9998Determination of the prevalence of antimicrobial resistance genes in canine Clostridium perfringens isolates. Clostridium perfringens is a well documented cause of a mild self-limiting diarrhea and a potentially fatal acute hemorrhagic diarrheal syndrome in the dog. A recent study documented that 21% of canine C. perfringens isolates had MIC's indicative of resistance to tetracycline, an antimicrobial commonly recommended for treatment of C. perfringens-associated diarrhea. The objective of the present study was to further evaluate the antimicrobial susceptibility profiles of these isolates by determining the prevalence of specific resistance genes, their expression, and ability for transference between bacteria. One hundred and twenty-four canine C. perfringens isolates from 124 dogs were evaluated. Minimum inhibitory concentrations of tetracycline, erythromycin, tylosin, and metronidazole were determined using the CLSI Reference Agar Dilution Method. All isolates were screened for three tetracycline resistance genes: tetA(P), tetB(P) and tetM, and two macrolide resistance genes: ermB and ermQ, via PCR using primer sequences previously described. Ninety-six percent (119/124) of the isolates were positive for the tetA(P) gene, and 41% (51/124) were positive for both the tetA(P) and tetB(P) genes. No isolates were positive for the tetB(P) gene alone. Highly susceptible isolates (MIC< or = 4 microg/ml) were significantly more likely to lack the tetB(P) gene. One isolate (0.8%) was positive for the ermB gene, and one isolate was positive for the ermQ gene. The tetM gene was not found in any of the isolates tested. Two out of 15 tested isolates (13%) demonstrated transfer of tetracycline resistance via bacterial conjugation. Tetracycline should be avoided for the treatment of C. perfringens-associated diarrhea in dogs because of the relatively high prevalence of in vitro resistance, and the potential for conjugative transfer of antimicrobial resistance.200616330169