Heavy metal co-resistance with antibiotics amongst bacteria isolates from an open dumpsite soil. - Related Documents




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591701.0000Heavy metal co-resistance with antibiotics amongst bacteria isolates from an open dumpsite soil. Heavy metal co-resistance with antibiotics appears to be synergistic in bacterial isolates via similar mechanisms. This synergy has the potential to amplify antibiotics resistance genes in the environment which can be transferred into clinical settings. The aim of this study was to assess the co-resistance of heavy metals with antibiotics in bacteria from dumpsite in addition to physicochemical analysis. Sample collection, physicochemical analysis, and enumeration of total heterotrophic bacteria counts (THBC) were all carried out using standard existing protocols. Identified bacteria isolates were subjected to antibiotics sensitivity test using the Kirby Bauer disc diffusion technique and the resulting multidrug resistant (MDR) isolates were subjected to heavy metal tolerance test using agar dilution technique with increasing concentrations (50, 100, 150, 200 and to 250 μg/ml) of our study heavy metals. THBC ranged from 6.68 to 7.92 × 10(5) cfu/g. Out of the 20 isolates subjected to antibiotics sensitivity, 50% (n = 10) showed multiple drug resistance and these were B. subtilis, B. cereus, C. freundii, P. aeruginosa, Enterobacter sp, and E. coli (n = 5). At the lowest concentration (50 μg/ml), all the MDR isolates tolerated all the heavy metals, but at 250 μg/ml, apart from cadmium and lead, all test isolates were 100% sensitive to chromium, vanadium and cobalt. The control isolate was only resistant to cobalt and chromium at 50 μg/ml, but sensitive to other heavy metals at all concentrations The level of co-resistance shown by these isolates is a call for concern.202336820045
591810.9999Resistance to Antibiotics, Biocides, Preservatives and Metals in Bacteria Isolated from Seafoods: Co-Selection of Strains Resistant or Tolerant to Different Classes of Compounds. Multi-drug resistant bacteria (particularly those producing extended-spectrum β-lactamases) have become a major health concern. The continued exposure to antibiotics, biocides, chemical preservatives, and metals in different settings such as the food chain or in the environment may result in development of multiple resistance or co-resistance. The aim of the present study was to determine multiple resistances (biocides, antibiotics, chemical preservatives, phenolic compounds, and metals) in bacterial isolates from seafoods. A 75.86% of the 87 isolates studied were resistant to at least one antibiotic or one biocide, and 6.90% were multiply resistant to at least three biocides and at least three antibiotics. Significant (P < 0.05) moderate or strong positive correlations were detected between tolerances to biocides, between antibiotics, and between antibiotics with biocides and other antimicrobials. A sub-set of 30 isolates selected according to antimicrobial resistance profile and food type were identified by 16S rDNA sequencing and tested for copper and zinc tolerance. Then, the genetic determinants for biocide and metal tolerance and antibiotic resistance were investigated. The selected isolates were identified as Pseudomonas (63.33%), Acinetobacter (13.33%), Aeromonas (13.33%), Shewanella, Proteus and Listeria (one isolate each). Antibiotic resistance determinants detected included sul1 (43.33% of tested isolates), sul2 (6.66%), bla(TEM) (16.66%), bla(CTX-M) (16.66%), bla(PSE) (10.00%), bla(IMP) (3.33%), bla(NDM-1) (3.33%), floR (16.66%), aadA1 (20.0%), and aac(6')-Ib (16.66%). The only biocide resistance determinant detected among the selected isolates was qacEΔ1 (10.00%). A 23.30 of the selected isolates were able to grow on media containing 32 mM copper sulfate, and 46.60% on 8 mM zinc chloride. The metal resistance genes pcoA/copA, pcoR, and chrB were detected in 36.66, 6.66, and 13.33% of selected isolates, respectively. Twelve isolates tested positive for both metal and antibiotic resistance genes, including one isolate positive for the carbapenemase gene bla(NDM-1) and for pcoA/copA. These results suggest that exposure to metals could co-select for antibiotic resistance and also highlight the potential of bacteria on seafoods to be involved in the transmission of antimicrobial resistance genes.201728912764
554920.9999Analysis 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
280230.9998First Description of Various Bacteria Resistant to Heavy Metals and Antibiotics Isolated from Polluted Sites in Tunisia. Environmental bacteria belonging to various families were isolated from polluted water collected from ten different sites in Tunisia. Sites were chosen near industrial and urban areas known for their high degree of pollution. The aim of this study was to investigate cross-resistance between heavy metals (HM), i.e., silver, mercury and copper (Ag, Hg, and Cu), and antibiotics. In an initial screening, 80 isolates were selected on ampicillin, and 39 isolates, retained for further analysis, could grow on a Tris-buffered mineral medium with gluconate as carbon source. Isolates were identified based on their 16S rRNA gene sequence. Results showed the prevalence of antibiotic resistance genes, especially all isolates harbored the bla (TEM) gene. Some of them (15.38%) harbored bla (SHV). Moreover, several were even ESBLs and MBLs-producers, which can threaten the human health. On the other hand, 92.30%, 56.41%, and 51.28% of the isolates harbored the heavy metals resistance genes silE, cusA, and merA, respectively. These genes confer resistance to silver, copper, and mercury. A cross-resistance between antibiotics and heavy metals was detected in 97.43% of our isolates.202134335797
286240.9998Regulation Transcriptional of Antibiotic Resistance Genes (ARGs) in Bacteria Isolated from WWTP. The incidence of antibiotics and transcriptional regulation of ARGs in isolated bacteria from wastewater needs to be explored. By HPLC, in samples of untreated wastewater, ampicillin (49.74 ± 5.70 µg/mL), chloramphenicol (0.60 ± 0.03 µg/mL), tylosin (72.95 ± 2.03 µg/mL), and oxytetracycline (0.22 ± 0.01 µg/mL) was determined. Through metagenomic analysis identified 58 bacterial species belonging to 9 phyla and at least 14 species have shown resistance to a variety of antibiotics. Twenty-two bacterial isolates were proved to be resistant to fifteen antibiotics of new generation and used in medical research to combat infectious diseases. Fourteen strains were shown to harbor plasmids in size ranges of 2-5 Kb, 6-10 Kb and plasmids with size greater than 10 Kb. By quantitative PCR it was possible to identify genes sul, qnr, cat1, aadA1, and sat-1 gene were shown to be present in gDNA samples from treated and untreated samples of wastewater and by relative expression analysis, differential expression of cat1, ermB, act, and tetA genes was demonstrated in strains that showed identity with Escherichia coli, Bacteroides fragilis, and Salmonella thyphi, and that were stressed with different concentrations of antibiotics. The presence of ARGs in untreated water samples, as well as in bacterial isolates, was indicative that in these habitats there are microorganisms that can resist β-lactams, aminoglycosides, tetracyclines, sulfonamides, and quinolones.202337672120
280550.9998Multidrug-resistance and toxic metal tolerance of medically important bacteria isolated from an aquaculture system. The use of antimicrobials and toxic metals should be considered carefully in aquaculture and surrounding environments. We aimed to evaluate medically relevant bacteria in an aquaculture system and their susceptibility to antimicrobials and toxic metals. Selective cultures for enterobacteria (ENT), non-fermenting Gram-negative rods (NFR) and Gram-positive cocci (GPC) were obtained from water samples collected in two different year seasons. The isolated bacteria were biochemically identified and antimicrobial and toxic metal susceptibility patterns were determined. Overall, 407 representative strains were recovered. In general, bacteria isolated from fish ponds showed higher multiple antibiotic resistance indices when compared to those isolated from a water-fed canal. Resistance to penicillin and azithromycin was observed more frequently in the GPC group, whereas resistance to ampicillin and ampicillin/sulbactam or gentamicin was observed more frequently in the ENT and NFR groups, respectively. All the isolated bacteria were tolerant to nickel, zinc, chromium and copper at high levels (≥1,024 μg mL(-1)), whereas tolerance to cadmium and mercury varied among the isolated bacteria (2-1,024 μg mL(-1)). Multidrug-resistant bacteria were more frequent and diverse in fish ponds than in the water-fed canal. A positive correlation was observed between antimicrobial resistance and metal tolerance. The data point out the need for water treatment associated with the aquaculture system.201222972388
286860.9998Detection and Analysis of Drug and Disinfectant Resistance Genes in the Sewage of a Center for Disease Control and Prevention. PURPOSE: Sewage is a significant reservoir for drug and disinfectant resistance genes and a medium for dissemination. This study aimed to evaluate the presence of drug and disinfectant resistance genes in the sewage of a Center for Disease Control and Prevention (CDC) and to assess the risks of their dissemination. METHODS: Sewage from a CDC in Hangzhou was collected, filtered, and enriched, and its microorganisms were cultured. The isolated bacteria were identified, and the minimum inhibitory concentration (MIC) was determined. The drug and disinfectant resistance genes in the sewage and bacteria were detected through polymerase chain reaction amplification. RESULTS: Three kinds of bacteria were isolated from the sewage sample. The MIC for Sphingomonas and Staphylococcus xylosus against chlorine-containing disinfectants was 250 mg/L, whereas the MIC for Bacillus firmus was 500 mg/L. The β-lactam resistance gene TEM and the disinfectant resistance gene qacA were positive in the bacteria, whereas the β-lactam resistance genes TEM, SHV, and VIM-1, the tetracycline resistance gene tetM, the aminoglycoside resistance genes aac(6')/aph(2') and aph3'-III, and the disinfectant resistance genes qacA, qacE, and qacEΔ1 were positive in the sewage. CONCLUSION: Drug and disinfectant resistance genes were found in the sewage of a CDC and were associated with bacteria. Thus, optimizing the monitoring and treatment of sewage is crucial.202540303605
286770.9998Enzymatic Activity and Horizontal Gene Transfer of Heavy Metals and Antibiotic Resistant Proteus vulgaris from Hospital Wastewater: An Insight. Globally, the issue of microbial resistance to medicines and heavy metals is getting worse. There are few reports or data available for Proteus vulgaris (P. vulgaris), particularly in India. This investigation intends to reveal the bacteria's ability to transmit genes and their level of resistance as well. The wastewater samples were taken from several hospitals in Lucknow City, India, and examined for the presence of Gram-negative bacteria that were resistant to antibiotics and heavy metals. The microbial population count in different hospital wastewaters decreases with increasing concentrations of metal and antibiotics. Among all the examined metals, Ni and Zn had the highest viable counts, whereas Hg, Cd, and Co had the lowest viable counts. Penicillin, ampicillin, and amoxicillin, among the antibiotics, demonstrated higher viable counts, whereas tetracycline and erythromycin exhibited lower viable counts. The MIC values for the P. vulgaris isolates tested ranged from 50 to 16,00 μg/ml for each metal tested. The multiple metal resistance (MMR) index, which ranged from 0.04 to 0.50, showed diverse heavy metal resistance patterns in all P. vulgaris isolates (in the case of 2-7 metals in various combinations). All of the tested isolates had methicillin resistance, whereas the least number of isolates had ofloxacin, gentamycin, or neomycin resistance. The P. vulgaris isolates displayed multidrug resistance patterns (2-12 drugs) in various antibiotic combinations. The MAR indexes were shown to be between (0.02-0.7). From the total isolates, 98%, 84%, and 80% had urease, gelatinase, and amylase activity, whereas 68% and 56% displayed protease and beta-lactamase activity. Plasmids were present in all the selected resistant isolates and varied in size from 42.5 to 57.0 kb and molecular weight from 27.2 to 37.0 MD. The transmission of the antibiotic/metal resistance genes was evaluated between a total of 7 pairs of isolates. A higher transfer frequency (4.4 × 10(-1)) was observed among antibiotics, although a lower transfer frequency (1.0 × 10(-2)) was observed against metals in both the media from the entire site tested. According to exponential decay, the population of hospital wastewater declined in the following order across all sites: Site II > Site IV > Site III > Site I for antibiotics and site IV > site II > site I >site III for metal. Different metal and antibiotic concentrations have varying effects on the population. The metal-tolerant P. vulgaris from hospital wastewater was studied in the current study had multiple distinct patterns of antibiotic resistance. It could provide cutting-edge methods for treating infectious diseases, which are essential for managing and assessing the risks associated with hospital wastewater, especially in the case of P. vulgaris.202236523753
286580.9998Antibiotic resistance in soil and water environments. Seven locations were screened for antibiotic-resistant bacteria using a modified agar dilution technique. Isolates resistant to high levels of antibiotics were screened for r plasmids. Low-level resistance (25 micro g x ml(-1)) was widespread for ampicillin, penicillin, tetracycline, vancomycin and streptomycin but not for kanamycin. Resistant populations dropped sharply at high antibiotic levels, suggesting that intrinsic non-emergent mechanisms were responsible for the multiple drug resistance exhibited at low doses. Dairy farm manure contained significantly (P < 0.01) more (%) resistant bacteria than the other sites. Bacteria isolated from a dairy water canal, a lake by a hospital and a residential garden (fertilized by farm manure) displayed resistance frequencies of 77, 75 and 70%, respectively. Incidence of tetracycline resistance was most prevalent at 47-89% of total bacteria. Out of 200 representative isolates analyzed, Pseudomonas, Enterococcus-like bacteria, Enterobacter and Burkholderia species constituted the dominant reservoirs of resistance at high drug levels (50-170 micro g x ml(-1)). Plasmids were detected in only 29% (58) of these bacteria with tetracycline resistance accounting for 65% of the plasmid pool. Overall, resistance trends correlated to the abundance and type of bacterial species present in the habitat. Environmental reservoirs of resistance include opportunistic pathogens and constitute some public health concern.200212396530
273690.9998Characterization of Bacterial Communities and Their Antibiotic Resistance Profiles in Wastewaters Obtained from Pharmaceutical Facilities in Lagos and Ogun States, Nigeria. In Nigeria, pharmaceutical wastewaters are routinely disseminated in river waters; this could be associated with public health risk to humans and animals. In this study, we characterized antibiotic resistant bacteria (ARB) and their antibiotic resistance profile as well as screening for sul1 and sul2 genes in pharmaceutical wastewater effluents. Bacterial composition of the wastewater sources was isolated on non-selective media and characterized by the polymerase chain reaction (PCR) amplification of the 16S rRNA genes, with subsequent grouping using restriction fragment length polymorphism (RFLP) and sequencing. The antibiotics sensitivity profiles were investigated using the standard disk diffusion plate method and the minimum inhibitory concentrations (MICs) of selected antibiotics on the bacterial isolates. A total of 254 bacterial strains were isolated, and majority of the isolates were identified as Acinetobacter sp., Klebsiella pneumonia, Proteus mirabilis, Enterobacter sp. and Bacillus sp. A total of 218 (85.8%) of the bacterial isolates were multidrug resistant. High MICs values were observed for all antibiotics used in the study. The result showed that 31.7%, 21.7% and 43.3% of the bacterial isolates harbored sul1, sul2, and Intl1 genes, respectively. Pharmaceuticals wastewaters are potential reservoirs of ARBs which may harbor resistance genes with possible risk to public health.201829966226
2731100.9998Prevalence of tetracycline resistance genes among multi-drug resistant bacteria from selected water distribution systems in southwestern Nigeria. BACKGROUND: Antibiotic resistance genes [ARGs] in aquatic systems have drawn increasing attention they could be transferred horizontally to pathogenic bacteria. Water treatment plants (WTPs) are intended to provide quality and widely available water to the local populace they serve. However, WTPs in developing countries may not be dependable for clean water and they could serve as points of dissemination for antibiotic resistant bacteria. Only a few studies have investigated the occurrence of ARGs among these bacteria including tetracycline resistance genes in water distribution systems in Nigeria. METHODOLOGY: Multi-drug resistant (MDR) bacteria, including resistance to tetracycline, were isolated from treated and untreated water distribution systems in southwest Nigeria. MDR bacteria were resistant to >3 classes of antibiotics based on break-point assays. Isolates were characterized using partial 16S rDNA sequencing and PCR assays for six tetracycline-resistance genes. Plasmid conjugation was evaluated using E. coli strain DH5α as the recipient strain. RESULTS: Out of the 105 bacteria, 85 (81 %) and 20 (19 %) were Gram- negative or Gram- positive, respectively. Twenty-nine isolates carried at least one of the targeted tetracycline resistance genes including strains of Aeromonas, Alcaligenes, Bacillus, Klebsiella, Leucobacter, Morganella, Proteus and a sequence matching a previously uncultured bacteria. Tet(A) was the most prevalent (16/29) followed by tet(E) (4/29) and tet30 (2/29). Tet(O) was not detected in any of the isolates. Tet(A) was mostly found with Alcaligenes strains (9/10) and a combination of more than one resistance gene was observed only amongst Alcaligenes strains [tet(A) + tet30 (2/10), tet(A) + tet(E) (3/10), tet(E) + tet(M) (1/10), tet(E) + tet30 (1/10)]. Tet(A) was transferred by conjugation for five Alcaligenes and two E. coli isolates. CONCLUSIONS: This study found a high prevalence of plasmid-encoded tet(A) among Alcaligenes isolates, raising the possibility that this strain could shuttle resistance plasmids to pathogenic bacteria.201526108344
2903110.9998Soil Bacteria in Urban Community Gardens Have the Potential to Disseminate Antimicrobial Resistance Through Horizontal Gene Transfer. Fifteen soil and 45 vegetable samples from Detroit community gardens were analyzed for potential antimicrobial resistance contamination. Soil bacteria were isolated and tested by antimicrobial susceptibility profiling, horizontal gene transfer, and whole-genome sequencing. High-throughput 16S rRNA sequencing analysis was conducted on collected soil samples to determine the total bacterial composition. Of 226 bacterial isolates recovered, 54 were from soil and 172 from vegetables. A high minimal inhibitory concentration (MIC) was defined as the MIC greater than or equal to the resistance breakpoint of Escherichia coli for Gram-negative bacteria or Staphylococcus aureus for Gram-positive bacteria. The high MIC was observed in 63.4 and 69.8% of Gram-negative isolates from soil and vegetables, respectively, against amoxicillin/clavulanic acid, as well as 97.5 and 82.7% against ampicillin, 97.6 and 90.7% against ceftriaxone, 85.4 and 81.3% against cefoxitin, 65.8 and 70.5% against chloramphenicol, and 80.5 and 59.7% against ciprofloxacin. All Gram-positive bacteria showed a high MIC to gentamicin, kanamycin, and penicillin. Forty of 57 isolates carrying tetM (70.2%) successfully transferred tetracycline resistance to a susceptible recipient via conjugation. Whole-genome sequencing analysis identified a wide array of antimicrobial resistance genes (ARGs), including those encoding AdeIJK, Mex, and SmeDEF efflux pumps, suggesting a high potential of the isolates to become antimicrobial resistant, despite some inconsistency between the gene profile and the resistance phenotype. In conclusion, soil bacteria in urban community gardens can serve as a reservoir of antimicrobial resistance with the potential to transfer to clinically important pathogens, resulting in food safety and public health concerns.202134887843
5550120.9998Prevalence, 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
2904130.9998The maintenance in the oral cavity of children of tetracycline-resistant bacteria and the genes encoding such resistance. OBJECTIVES: To investigate the maintenance of tetracycline-resistant oral bacteria and the genes encoding tetracycline resistance in these bacteria in children (aged 4--6 years) over a period of 12 months. METHODS: Plaque and saliva samples were taken from 26 children. Tetracycline-resistant bacteria were isolated and identified. The types of resistance genes and their genetic locations were also determined. RESULTS: Fifteen out of 18 children harboured tetracycline-resistant (defined as having a MIC>or=8 mg/L) oral bacteria at all three time points. The median percentage of tetracycline-resistant bacteria at 0, 6 and 12 months was 1.37, 1.37 and 0.85%, respectively; these were not significantly different. The MIC(50) of the group was 64 mg/L at all three time points compared with the MIC(90), which was 64 mg/L at 0 months, and 128 mg/L at 6 and 12 months. The most prevalent resistant species were streptococci (68%), which were isolated at all three time points in 13 children. The most prevalent gene encoding tetracycline resistance was tet(M) and this was found in different species at all three time points. For the first time, tet(32) was found in Streptococcus parasanguinis and Eubacterium saburreum. PCR and Southern-blot analysis (on isolates from three of the children) showed that the tet(M) gene was located on a Tn916-like element and could be detected at all three time points, in four different genera, Streptococcus, Granulicatella, Veillonella and Neisseria. CONCLUSIONS: The results of this study show that tetracycline-resistant bacteria and tet(M) are maintained within the indigenous oral microbiota of children, even though they are unlikely to have been directly exposed to tetracycline.200516027144
2861140.9998Antibiotic Resistance Profiles and Genomic Analysis of Endophytic Bacteria Isolates from Wild Edible Fungi in Yunnan. The use of antibiotics has led to the emergence of antibiotic resistance, posing significant challenges in the prevention, control, and treatment of microbial diseases, while threatening public health, the environment, and food safety. In this study, the antibiotic resistance phenotypes and genotypes of 56 endophytic bacteria isolates from three species of wild edible fungi in Yunnan were analyzed using the Kirby-Bauer disk diffusion method and PCR amplification. The results revealed that all isolates were sensitive to ofloxacin, but resistance was observed against 17 other antibiotics. Specifically, 55, 53, and 51 isolates exhibited resistance to amoxicillin, penicillin, and vancomycin, respectively. Antibiotic resistance gene (ARG) detection indicated that the sulfonamide sul1 gene had the highest detection rate (53.57%). Excluding the ARG that was not detected, the lowest detection rates were the sulfonamide sul2 and sul3 genes, both at 1.79%. Among six tetracycline resistance genes, only tetK and tetM were detected. For β-lactam antibiotics, blaTEM, blaVIM, and blaSHV genes were present, while blaOXA was absent. In aminoglycoside resistance genes, aadB was not detected, while detection rates for aac(3')-IIa, acrB, and aadA1 were 3.57%, 1.79%, and 37.5%, respectively. The chloramphenicol Cat gene was detected at a rate of 14.29%, whereas floR was absent. For polypeptide resistance, VanC was detected at 3.57%, with EmgrB not detected. All three quinolone genes were detected, with detection rates of 8.92% for GyrA, 39.29% for GyrB, and 37.5% for ParC. Through phylogenetic analysis, 12 isolates that are closely related to ten common foodborne pathogenic bacteria were further selected for whole-genome sequencing and assembly. Gene annotations revealed that each isolate contained more than 15 ARGs and over 30 virulence factors. Notably, the detection rate of antibiotic resistance phenotypes was higher than that of genotypes, highlighting the importance of studying phenotypic antibiotic resistance that lacks identifiable ARGs. This study enriches the research on endophytes in wild edible fungi and provides new data for microbial ecology and antibiotic resistance research. It also offers critical insights for monitoring microbial antibiotic resistance in wild edible fungi and potentially other food sources, contributing to more effective strategies for ecological protection, sustainable agricultural development, and public health security.202540005728
2803150.9998Antimicrobial resistance, heavy metal resistance and integron content in bacteria isolated from a South African tilapia aquaculture system. Antibacterial compounds and metals co-select for antimicrobial resistance when bacteria harbour resistance genes towards both types of compounds, facilitating the proliferation and evolution of antimicrobial and heavy metal resistance. Antimicrobial and heavy metal resistance indices of 42 Gram-negative bacteria from a tilapia aquaculture system were determined to identify possible correlations between these phenotypes. Agar dilution assays were carried out to determine susceptibility to cadmium, copper, lead, mercury, chromate and zinc, while susceptibility to 21 antimicrobial agents was investigated by disk diffusion assays. Presence of merA, the mercury resistance gene, was determined by dot-blot hybridizations and PCR. Association of mercury resistance with integrons and transposon Tn21 was also investigated by PCR. Isolates displayed a high frequency of antimicrobial (erythromycin: 100%; ampicillin: 85%; trimethoprim: 78%) and heavy metal (Zn2+: 95%; Cd2+: 91%) resistance. No correlation was established between heavy metal and multiple antibiotic resistance indices. Significant positive correlations were observed between heavy metal resistance profiles, indices, Cu2+ and Cr3+ resistance with erythromycin resistance. Significant positive correlations were observed between merA (24%)/Tn21 (24%) presence and heavy metal resistance profiles and indices; however, significant negative correlations were obtained between integron-associated qacE∆1 (43%) and sulI (26%) gene presence and heavy metal resistance indices. Heavy metal and antimicrobial agents co-select for resistance, with fish-associated, resistant bacteria demonstrating simultaneous heavy metal resistance. Thus, care should be taken when using anti-fouling heavy metals as feed additives in aquaculture facilities.201729160218
5553160.9998Detection 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
5916170.9998Co-transfer of resistance to high concentrations of copper and first-line antibiotics among Enterococcus from different origins (humans, animals, the environment and foods) and clonal lineages. OBJECTIVES: We studied the occurrence of diverse copper (Cu) tolerance genes from Gram-positive bacteria and their co-transfer with antibiotic resistance genes among Enterococcus from diverse sources. METHODS: Enterococcus (n = 922) of several species and from human, animal, environment and food samples were included. Antimicrobial and CuSO4 susceptibility and conjugation assays were performed by standard procedures, bacterial screening of Cu and antibiotic resistance genes by PCR, and clonality by PFGE/multilocus sequence typing. RESULTS: tcrB and cueO genes occurred in 15% (n = 137/922) and 14% (n = 128/922) of isolates, respectively, with the highest occurrence in piggeries (P < 0.05). They were more frequent among Enterococcus faecium (tcrB: 23% versus 8% in Enterococcus faecalis and 12% in other species; cueO: 25% versus 5% and 9%, respectively; P < 0.05). A correlation between phenotypic and genotypic assays was observed for most E. faecium (CuSO4 MIC50 = 24 mM in tcrB/cueO(+) versus CuSO4 MIC50 = 12 mM in tcrB/cueO(-)), but not for other species. Co-transfer of Cu tolerance (associated with tcrB, cueO or an unknown mechanism) with erythromycin, tetracycline, vancomycin, aminoglycosides or ampicillin resistance was demonstrated. A variety of PFGE types was detected among isolates carrying Cu tolerance mechanisms, some identified in sequence types (STs) often linked to human infections (E. faecium from ST18 and ST78 clonal lineages and E. faecalis clonal complex 2). CONCLUSIONS: Cu tolerance might contribute to the selection/maintenance of multidrug-resistant Enterococcus (including resistance to first-line antibiotics used to treat enterococcal infections) due to the use of Cu compounds (e.g. antiseptics/animal feed supplements). The distribution of the multicopper oxidase cueO and the co-transfer of ampicillin resistance along with Cu tolerance genes are described for the first time.201424343895
5915180.9998Characterization of Two Macrolide Resistance-Related Genes in Multidrug-Resistant Pseudomonas aeruginosa Isolates. In analyzing the drug resistance phenotype and mechanism of resistance to macrolide antibiotics of clinical Pseudomonas aeruginosa isolates, the agar dilution method was used to determine the minimum inhibitory concentrations (MICs), and PCR (polymerase chain reaction) was applied to screen for macrolide antibiotics resistance genes. The macrolide antibiotics resistance genes were cloned, and their functions were identified. Of the 13 antibiotics tested, P. aeruginosa strains showed high resistance rates (ranging from 69.5-82.1%), and MIC levels (MIC90 > 256 μg/ml) to macrolide antibiotics. Of the 131 known macrolide resistance genes, only two genes, mphE and msrE, were identified in 262 clinical P. aeruginosa isolates. Four strains (1.53%, 4/262) carried both the msrE and mphE genes, and an additional three strains (1.15%, 3/262) harbored the mphE gene alone. The cloned msrE and mphE genes conferred higher resistance levels to three second-generation macrolides compared to two first-generation ones. Analysis of MsrE and MphE protein polymorphisms revealed that they are highly conserved, with only 1-3 amino acids differences between the proteins of the same type. It can be concluded that even though the strains showed high resistance levels to macrolides, known macrolide resistance genes are seldom present in clinical P. aeruginosa strains, demonstrating that a mechanism other than this warranted by the mphE and msrE genes may play a more critical role in the bacteria's resistance to macrolides.202033574864
5547190.9998Antibiotic Resistant Bacterial Isolates from Captive Green Turtles and In Vitro Sensitivity to Bacteriophages. This study aimed to test multidrug resistant isolates from hospitalised green turtles (Chelonia mydas) and their environment in North Queensland, Australia, for in vitro susceptibility to bacteriophages. Seventy-one Gram-negative bacteria were isolated from green turtle eye swabs and water samples. Broth microdilution tests were used to determine antibiotic susceptibility. All isolates were resistant to at least two antibiotics, with 24% being resistant to seven of the eight antibiotics. Highest resistance rates were detected to enrofloxacin (77%) and ampicillin (69.2%). More than 50% resistance was also found to amoxicillin/clavulanic acid (62.5%), ceftiofur (53.8%), and erythromycin (53.3%). All the enriched phage filtrate mixtures resulted in the lysis of one or more of the multidrug resistant bacteria, including Vibrio harveyi and V. parahaemolyticus. These results indicate that antibiotic resistance is common in Gram-negative bacteria isolated from hospitalised sea turtles and their marine environment in North Queensland, supporting global concern over the rapid evolution of multidrug resistant genes in the environment. Using virulent bacteriophages as antibiotic alternatives would not only be beneficial to turtle health but also prevent further addition of multidrug resistant genes to coastal waters.201729147114