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526100.9889Prevalence of antibiotic resistance genes from effluent of coastal aquaculture, South Korea. The wide use of antibiotics in aquaculture for prophylactic and therapeutic purposes can potentially lead to the prevalence of antibiotic resistance genes (ARGs). This study reports for the first time the profile of ARGs from effluents of coastal aquaculture located in South Jeolla province and Jeju Island, South Korea. Using quantitative PCR (qPCR), twenty-two ARGs encoding tetracycline resistance (tetA, tetB, tetD, tetE, tetG, tetH, tetM, tetQ, tetX, tetZ, tetBP), sulfonamide resistance (sul1, sul2), quinolone resistance (qnrD, qnrS, aac(6')-Ib-cr), β-lactams resistance (bla(TEM), bla(CTX), bla(SHV)), macrolide resistance (ermC), florfenicol resistance (floR) and multidrug resistance (oqxA) and a class 1 integrons-integrase gene (intI1) were quantified. In addition, Illumina Miseq sequencing was applied to investigate microbial community differences across fish farm effluents. Results from qPCR showed that the total number of detected ARGs ranged from 4.24 × 10(-3) to 1.46 × 10(-2) copies/16S rRNA gene. Among them, tetB and tetD were predominant, accounting for 74.8%-98.0% of the total ARGs. Furthermore, intI1 gene showed positive correlation with tetB, tetD, tetE, tetH, tetX, tetZ tetQ and sul1. Microbial community analysis revealed potential host bacteria for ARGs and intI1. Two genera, Vibrio and Marinomonas belonging to Gammaproteobacteria, showed significant correlation with tetB and tetD, the most dominant ARGs in all samples. Also, operational taxonomic units (OTUs)-based network analysis revealed that ten OTUs, classified into the phyla Proteobacteria, Cyanobacteria/Chloroplast, Bacteroidetes, Verrucomicrobia and an unclassified phylum, were potential hosts of tetracycline resistance genes (i.e., tetA, tetG, tetH, tetM, tetQ and tetZ). Further systematic monitoring of ARGs is warranted for risk assessment and management of antibacterial resistance from fish farm effluents.201829031406
348110.9886Antibiotics and Antibiotic Resistance Genes in Sediment of Honghu Lake and East Dongting Lake, China. Sediment is an ideal medium for the aggregation and dissemination of antibiotics and antibiotic resistance genes (ARGs). The levels of antibiotics and ARGs in Honghu Lake and East Dongting Lake of central China were investigated in this study. The concentrations of eight antibiotics (four sulfonamides and four tetracyclines) in Honghu Lake were in the range 90.00-437.43 μg kg(-1) (dry weight (dw)) with mean value of 278.21 μg kg(-1) dw, which was significantly higher than those in East Dongting Lake (60.02-321.04 μg kg(-1) dw, mean value of 195.70 μg kg(-1) dw). Among the tested three sulfonamide resistance genes (sul) and eight tetracycline resistance genes (tet), sul1, sul2, tetA, tetC, and tetM had 100 % detection frequency in sediment samples of East Dongting Lake, while only sul1, sul2, and tetC were observed in all samples of Honghu Lake. The relative abundance of sul2 was higher than that of sul1 at p < 0.05 level in both lakes. The relative abundance of tet genes in East Dongting Lake was in the following order: tetM > tetB > tetC > tetA. The relative abundance of sul1, sul2, and tetC in East Dongting Lake was significantly higher than those in Honghu Lake. The abundance of background bacteria may play an important role in the horizontal spread of sul2 and tetC genes in Honghu Lake and sul1 in East Dongting Lake, respectively. Redundancy analysis indicated that tetracyclines may play a more important role than sulfonamides in the abundance of sul1, sul2, and tetC gens in Honghu Lake and East Dongting Lake.201627418176
138020.9881Distribution of tetracycline and streptomycin resistance genes and class 1 integrons in Enterobacteriaceae isolated from dairy and nondairy farm soils. The prevalence of selected tetracycline and streptomycin resistance genes and class 1 integrons in Enterobacteriaceae (n = 80) isolated from dairy farm soil and nondairy soils was evaluated. Among 56 bacteria isolated from dairy farm soils, 36 (64.3%) were resistant to tetracycline, and 17 (30.4%) were resistant to streptomycin. Lower frequencies of tetracycline (9 of 24 or 37.5%) and streptomycin (1 of 24 or 4.2%) resistance were observed in bacteria isolated from nondairy soils. Bacteria (n = 56) isolated from dairy farm soil had a higher frequency of tetracycline resistance genes including tetM (28.6%), tetA (21.4%), tetW (8.9%), tetB (5.4%), tetS (5.4%), tetG (3.6%), and tetO (1.8%). Among 24 bacteria isolated from nondairy soils, four isolates carried tetM, tetO, tetS, and tetW in different combinations; whereas tetA, tetB, and tetG were not detected. Similarly, a higher prevalence of streptomycin resistance genes including strA (12.5%), strB (12.5%), ant(3'') (12.5), aph(6)-1c (12.5%), aph(3'') (10.8%), and addA (5.4%) was detected in bacteria isolated from dairy farm soils than in nondairy soils. None of the nondairy soil isolates carried aadA gene. Other tetracycline (tetC, tetD, tetE, tetK, tetL, tetQ, and tetT) and streptomycin (aph(6)-1c and ant(6)) resistance genes were not detected in both dairy and nondairy soil isolates. A higher distribution of multiple resistance genes was observed in bacteria isolated from dairy farm soil than in nondairy soil. Among 36 tetracycline- and 17 streptomycin-resistant isolates from dairy farm soils, 11 (30.6%) and 9 (52.9%) isolates carried multiple resistance genes encoding resistance to tetracycline and streptomycin, respectively, which was higher than in bacteria isolated from nondairy soils. One strain each of Citrobacter freundii and C. youngae isolated from dairy farm soils carried class 1 integrons with different inserted gene cassettes. Results of this small study suggest that the presence of multiple resistance genes and class 1 integrons in Enterobacteriaceae in dairy farm soil may act as a reservoir of antimicrobial resistance genes and could play a role in the dissemination of these antimicrobial resistance genes to other commensal and indigenous microbial communities in soil. However, additional longer-term studies conducted in more locations are needed to validate this hypothesis.200817701242
129530.9880Phenotypic and genotypic characterisation of antimicrobial resistance in faecal bacteria from 30 Giant pandas. To study the prevalence of antimicrobial resistance in faecal bacteria from Giant pandas in China, 59 isolates were recovered from faecal pats of 30 Giant pandas. Antimicrobial susceptibility testing of the isolates was performed by the standardised disk diffusion method (Kirby-Bauer). Of the 59 study isolates, 32.20% were resistant to at least one antimicrobial and 16.95% showed multidrug-resistant phenotypes. Thirteen drug resistance genes [aph(3')-IIa, aac(6')-Ib, ant(3'')-Ia, aac(3)-IIa, sul1, sul2, sul3, tetA, tetC, tetM, cat1, floR and cmlA] were analysed using four primer sets by multiplex polymerase chain reaction (PCR). The detection frequency of the aph(3')-IIa gene was the highest (10.17%), followed by cmlA (8.47%). The genes aac(6')-Ib, sul2 and tetA were not detected. PCR products were confirmed by DNA sequence analysis. The results revealed that multidrug resistance was widely present in bacteria isolated from Giant pandas.200919168331
137940.9879Antibiotic Resistance and Genetic Profiles of Vibrio parahaemolyticus Isolated from Farmed Pacific White Shrimp (Litopenaeus vannamei) in Ningde Regions. To better understand the antibiotic resistance, virulence genes, and some related drug-resistance genes of Vibrio parahaemolyticus in farmed pacific white shrimp (Litopenaeus vannamei) in Ningde regions, Fujian province, we collected and isolated a total of 102 strains of V. parahaemolyticus from farmed pacific white shrimp in three different areas of Ningde in 2022. The Kirby-Bauer disk method was used to detect V. parahaemolyticus resistance to 22 antibiotics, and resistant genes (such as quinolones (qnrVC136, qnrVC457, qnrA), tetracyclines (tet A, tetM, tetB), sulfonamides (sulI, sulII, sulIII), aminoglycosides (strA, strB), phenicols (cat, optrA, floR, cfr), β-lactams (carB), and macrolides (erm)) were detected by using PCR. The findings in this study revealed that V. parahaemolyticus was most resistant to sulfamoxazole, rifampicin, and erythromycin, with resistance rates of 56.9%, 36.3%, and 33.3%, respectively. Flufenicol, chloramphenicol, and ofloxacin susceptibility rates were 97.1%, 94.1%, and 92.2%, respectively. In all, 46% of the bacteria tested positive for multi-drug resistance. The virulence gene test revealed that all bacteria lacked the tdh and trh genes. Furthermore, 91.84% and 52.04% of the isolates were largely mediated by cat and sulII, respectively, with less than 5% resistance to aminoglycosides and macrolides. There was a clear mismatch between the antimicrobial resistance phenotypes and genotypes, indicating the complexities of V. parahaemolyticus resistance.202438257979
526250.9879High abundances of class 1 integrase and sulfonamide resistance genes, and characterisation of class 1 integron gene cassettes in four urban wetlands in Nigeria. There is little information about environmental contamination with antibiotic resistance genes (ARG) in Sub-Saharan Africa, home to about 1 billion people. In this study we measured the abundance of three genes (sul1, sul2, and intI1) used as indicators of environmental contamination with ARGs in the sediments of four urban wetlands in southwestern Nigeria by qPCR. In addition, we characterised the variable regions of class 1 integrons in sulfamethoxazole/trimethoprim (SMX/TRI)-resistant bacteria isolated from the wetlands by PCR and DNA sequencing. The indicator ARGs were present in all wetlands with mean absolute copy numbers/gram of sediment ranging between 4.7x106 and 1.2x108 for sul1, 1.1x107 and 1x108 for sul2, and 5.3x105 and 1.9x107 for intI1. The relative abundances (ARG/16S rRNA copy number) ranged from about 10-3 to 10-1. These levels of ARG contamination were similar to those previously reported for polluted environments in other parts of the world. The integrase genes intI1 and intI2 were detected in 72% and 11.4% SMX/TRI-resistant isolates, respectively. Five different cassette array types (dfrA7; aadA2; aadA1|dfrA1; acc(6')lb-cr|arr3|dfrA27; arr3|acc(6')lb-cr|dfrA27) were detected among 34 (59.6%) intI1-positive isolates. No gene cassettes were found in the nine intI2-positive isolates. These results show that African urban ecosystems impacted by anthropogenic activities are reservoirs of bacteria harbouring transferable ARG.201830496274
525960.9878Distribution of antibiotic resistance genes in Bosten Lake, Xinjiang, China. The occurrence of antibiotic resistance genes (ARGs) and resistant bacteria was quantified in 17 water samples collected across Bosten Lake, Xinjiang, China. The heterotrophic plate count method was used to detect the levels of sulfonamide- and tetracycline-resistant bacteria, which have mean concentrations of 2.50×10(5) and 4.63×10(3) CFU/mL, respectively. The resistance genes of sulfonamide (sul1, sul2) and tetracycline (tetM, tetO and tetW) were detected, and results showed that all other ARGs except the tetO gene were obtained from all samples. Four of the obtained ARGs were further quantified, and results showed that the sulfonamide resistance genes were prevalent. The relative abundance was in the range of 2.81×10(-5) to 3.33×10(-3) for the sul1/16s-rRNA and 1.04×10(-5) to 3.80×10(-3) for the sul2/16s-rRNA. For the tet genes, the relative concentrations of tetM/16s-rRNA and tetW16s-rRNA ranged from 1.18×10(-5) to 2.46×10(-4) and 1.58×10(-6) to 4.19×10(-4), respectively. The concentration divergence among ARGs may be related to the different characteristics of each gene. This study validated that Bosten Lake was affected by ARGs and resistant bacteria, thus turning the lake into an important reservoir for the transfer of ARGs and resistant bacteria.201425225942
524570.9878Antimicrobial Resistance in U.S. Retail Ground Beef with and without Label Claims Regarding Antibiotic Use. ABSTRACT: Antibiotics used during food animal production account for approximately 77% of U.S. antimicrobial consumption by mass. Ground beef products labeled as raised without antibiotics (RWA) are perceived to harbor lower levels of antimicrobial-resistant bacteria than conventional (CONV) products with no label claims regarding antimicrobial use. Retail ground beef samples were obtained from six U.S. cities. Samples with an RWA or U.S. Department of Agriculture Organic claim (n = 299) were assigned to the RWA production system. Samples lacking these claims (n = 300) were assigned to the CONV production system. Each sample was cultured for the detection of five antimicrobial-resistant bacteria. Genomic DNA was isolated from each sample, and a quantitative PCR assay was used to determine the abundance of 10 antimicrobial resistance (AMR) genes. Prevalence of tetracycline-resistant Escherichia coli (CONV, 46.3%; RWA, 34.4%; P < 0.01) and erythromycin-resistant Enterococcus (CONV, 48.0%; RWA, 37.5%; P = 0.01) was higher in CONV ground beef. Salmonella was detected in 1.2% of samples. The AMR gene blaCTX-M (CONV, 4.1 log-normalized abundance; RWA, 3.8 log-normalized abundance; P < 0.01) was more abundant in CONV ground beef. The AMR genes mecA (CONV, 4.4 log-normalized abundance; RWA, 4.9 log-normalized abundance; P = 0.05), tet(A) (CONV, 3.9 log-normalized abundance; RWA, 4.5 log-normalized abundance; P < 0.01), tet(B) (CONV, 3.9 log-normalized abundance; RWA, 4.5 log-normalized abundance; P < 0.01), and tet(M) (CONV, 5.4 log-normalized abundance; RWA, 5.8 log-normalized abundance; P < 0.01) were more abundant in RWA ground beef. Although these results suggest that antimicrobial use during U.S. cattle production does not increase human exposure to antimicrobial-resistant bacteria via ground beef, quantitative microbiological risk assessments are required for authoritative determination of the human health impacts of the use of antimicrobial agents during beef production.202133302298
138180.9878Differences in antimicrobial resistance-related genes of Trueperella pyogenes between isolates detected from cattle and pigs. We investigated antimicrobial resistance-related genes in 109 isolates of Trueperella pyogenes that were isolated in cattle and pigs. All 89 tetracycline-resistant T. pyogenes isolates carried the resistance gene harbored either tetW, tetM, tetA(33), tetK, or tetL. The ermX or ermB were detected in 18 of 23 erythromycin-resistant isolates. Streptomycin-resistant aadA1, aadA9, aadA11, aadA24, strA, or strB were detected in 25 of 83 isolates. There were significant differences in the percentages of tetA(33), ermB, aadA1, aadA9, aadA11, or aadA24 carriage between cattle and pig isolates. In addition, the Class 1 gene cassette was detected only in 17 cattle isolates. This suggests that T. pyogenes isolates acquire resistance gene in each environment of cattle and pigs, and that the transmission of the bacteria between cattle and pigs is limited.202439293943
131990.9877Isolation and Identification of Aerobic Bacteria Carrying Tetracycline and Sulfonamide Resistance Genes Obtained from a Meat Processing Plant. Microbial contamination in food-processing plants can play a fundamental role in food quality and safety. The purpose of this study was to investigate aerobic bacteria carrying tetracycline and sulfonamide resistance genes from a meat processing plant as possible sources of meat contamination. One hundred swab samples from surfaces of conveyor belts, meat slicers, meat knives, benches, plastic trays, gloves, and aprons were analyzed. A total of 168 isolates belonging to 10 genera were obtained, including Pseudomonas sp. (n = 35), Acinetobacter sp. (n = 30), Aeromonas sp. (n = 20), Myroides sp. (n = 15), Serratia sp. (n = 15), Staphylococcus sp. (n = 14), Enterobacter sp. (n = 11), Escherichia coli (n = 10), Lactococcus sp. (n = 10), and Klebsiella sp. (n = 8). Of the 168 isolates investigated, 60.7% showed resistance to tetracycline and 57.7% to trimethoprim/sulfamethoxazole. The tetracycline resistance genes tetL, tetA, tetB, tetC, tetE, tetM, tetS, tetK, and tetX were found in the frequency of 7.7%, 6.0%, 4.8%, 4.8%, 3.6%, 3.6%, 3.6%, 1.2%, and 0.6%, respectively. Sulfonamide resistance genes sul1 and sul2 were observed in the frequency of 17.9% and 38.1%, respectively. The tetracycline resistance genes tetX was first found in Myroides sp. This investigation demonstrated that food contact surfaces in a meat processing plant may be sources of contamination of aerobic bacteria carrying tetracycline and sulfonamide antibiotic resistance genes.201627100915
1375100.9877Characterization of integrons and their cassettes in Escherichia coli and Salmonella isolates from poultry in Korea. Ninety-nine Escherichia coli and 33 Salmonella isolates were assessed for antimicrobial susceptibility (disc diffusion test). Sulfonamide and tetracycline resistance genes were identified through PCR, and class 1 and class 2 integrons with resistance gene cassettes were identified with PCR followed by sequencing. Salmonella (63.6%) and E. coli (85.8%) isolates were multidrug resistant (resistance to 3 or more antimicrobials), and the highest incidences of resistance were observed for tetracycline, nalidixic acid, and sulfamethoxazole. The sul1, sul2, tetA, and tetB resistance determinant genes were predominant in E. coli, whereas only sul2 and tetA were identified in Salmonella isolates. In the E. coli isolates, 54 (54.5%) class 1 integrons, 6 (6.1%) class 2 integrons, and 5 (5.1%) class 1 and class 2 integrons together were detected, whereas only 3 (9.1%) integrons were found in the Salmonella serovars. Around 87% of the integrons in E. coli harbored resistance gene cassettes conferring resistance to streptomycin/spectinomycin (aadA, aminoglycoside resistance gene), trimethoprim (dfrA, dihydrofolate reductase gene), streptothricin [sat1 and sat2 (streptothricin acetyltransferase), and estX (putative esterases)]. The most common gene cassettes were aadA1+dfrA1 and dfrA1+sat2+aadA1 in class 1 and class 2 integrons, respectively. Other cassettes including aadA5+dfrA7, dfrA12+aadA2, aadA2+aadA1+dfrA12, and aadA5+aadA2/dfrA7 were also identified. Among the Salmonella serovars, Salmonella Malmoe harbored aadA1+dfrA1 and dfrA12+sat2+aadA1 genes. The aadA1, aadA2, sat2, and dfrA1 had wide variation in similarity among themselves and from previously reported genes worldwide. The diverse gene cassettes could be responsible for the prominent resistance profiles observed and a potential source for dissemination of antimicrobial resistance determinants to other bacteria.201324135609
1377110.9876Characterization and Horizontal Transfer of Antimicrobial Resistance Genes and Integrons in Bacteria Isolated from Cooked Meat Products in China. The aim of this study was to investigate antimicrobial resistance and the presence and transferability of corresponding resistance genes and integrons in bacteria isolated from cooked meat samples in the People's Republic of China. A total of 150 isolates (22 species belonging to 15 genera) were isolated from 49 samples. Resistance of these isolates to antimicrobials was commonly observed; 42.7, 36.0, and 25.3% of the isolates were resistant to tetracycline, streptomycin, and ampicillin, respectively. Multidrug resistance was observed in 41 (27.3%) of the isolates. Sixteen resistance genes, i.e., bla(TEM-1) and bla(CTX-M-14) (β-lactams), aac(3)-IIa (gentamicin), strA and strB (streptomycin), qnrB and qnrS (fluoroquinolone), sul1, sul2, and sul3 (sulfamethoxazole), cat1 and cat2 (chloramphenicol), and tetM, tetA, tetS, and tetB (tetracycline), were found in 54 isolates. One isolate of Pseudomonas putida carried qnrB, and sequence analysis of the PCR product revealed 96% identity to qnrB2. The qnr genes were found coresiding and were cotransferred with bla genes in two isolates. Twelve isolates were positive for the class 1 integrase gene, and four isolates carried the class 2 integrase gene. However, no class 3 integrase gene was detected. One isolate of Proteus mirabilis carried dfrA32-ereA-aadA2, and this unusual array could be transferred to Escherichia coli. Nonclassic class 1 integrons lacking qacEΔ1 and sul1 genes were found in 2 of the 12 intI1-positive isolates. Our results revealed the presence of multidrug-resistant bacteria in cooked meats and the presence and transferability of resistance genes in some isolates, suggesting that cooked meat products may act as reservoirs of drug-resistant bacteria and may facilitate the spread of resistance genes.201729148877
1376120.9875Incidence of class 1 integron and other antibiotic resistance determinants in Aeromonas spp. from rainbow trout farms in Australia. There is limited information on antibiotic resistance determinants present in bacteria of aquaculture origin in Australia. The presence of integron and other resistance determinants was investigated in 90 Aeromonas isolates derived from nine freshwater trout farms in Victoria (Australia). Polymerase chain reaction was carried out for the detection of integrase genes Int1, Int2 and Int3, gene cassette array, integron-associated aadA, sul1 and qac1 genes, streptomycin resistance genes strA-strB, β-lactamase resistance genes bla(TEM) and bla(SHV) , and tetracycline resistance genes tetA-E and tetM. Clonal analysis was performed by pulsed-field gel electrophoresis (PFGE). Class 1 integrons were detected in 28/90 (31%) and class 2 and class 3 in none of the strains, aadA gene in 19/27 (70%) streptomycin-resistant strains, sul1 in 13/15 (86.7%) sulphonamide-resistant strains and qac1 gene in 8/28 (28.6%) integron-bearing strains. Five strains from two different farms carried gene cassettes of 1000 bp each containing the aadA2 gene and PFGE analysis revealed genetic relatedness. tetC was detected in all and tetA in 9/18 (50%) tetracycline-resistant strains. The strA-strB, bla(TEM) or bla(SHV) genes were not detected in any of the strains. Aeromonas spp. carrying integrons and other resistance genes are present in farm-raised fish and sediments even though no antibiotics were licensed for use in Australian aquaculture at the time of the study.201121762170
1353130.9875Dissemination of antibiotic resistance genes, mobile genetic elements, and efflux genes in anthropogenically impacted riverine environments. Anthropogenically impacted surface waters are an important reservoir for multidrug-resistant bacteria and antibiotic-resistant genes. The present study aimed at MDR, ESBL, AmpC, efflux genes, and heavy metals resistance genes (HMRGs) in bacterial isolates from four Indian rivers belonging to different geo-climatic zones, by estimating the mode of resistance transmission exhibited by the resistant isolates. A total 71.27% isolates exhibited MDR trait, showing maximum resistance towards β-lactams (P = 66.49%; AMX = 59.04%), lincosamides (CD = 65.96%), glycopeptides (VAN = 25.19%; TEI = 56.91%), cephalosporins (CF = 53.72%; CXM = 30.32%) sulphonamide (COT = 43.62%; TRIM = 12.77%), followed by macrolide and tetracycline. The dfrA1 and dfrB genes were detected in total 37.5% isolates whereas; dfrA1 genes were detected in 33.34%. The sul1 gene was detected in 9.76% and sul2 gene was detected in 2.44% isolates. A total of 69.40% MDR integron positive isolates were detected with intI1and intI2 detected at 89.25% and 1.07%, respectively; encoding class 1 and class 2 integron-integrase. ESBL production was confirmed in 73.13% isolates that harboured the genes blaTEM (96.84%), blaSHV (27.37%), blaOXA (13.68%) and blaCTXM (18.95%) while the frequency of HMRGs; 52.24% (zntB), 33.58% (chrA), and 6.72% (cadD). Efflux activity was confirmed in 96.26% isolates that harbored the genes acrA (93.02%), tolC (88.37%), and acrB (86.04%). AmpC (plasmid-mediated) was detected in 20.9% of the riverine isolates. Detection of such hidden molecular modes of antibiotic resistance in the rivers is alarming that requires urgent and stringent measures to control the resistance threats.202133524742
834140.9875Molecular diversity of class 2 integrons in antibiotic-resistant gram-negative bacteria found in wastewater environments in China. The molecular architecture of class 2 integrons among gram-negative bacteria from wastewater environments was investigated in Jinan, China. Out of the 391 antibiotic-resistant bacteria found, 38 isolates harboring class 2 integrons encoding potentially transferrable genes that could confer antibiotic resistance were found. These isolates were classified into 19 REP-PCR types. These strains were identified using 16S rRNA gene sequencing and found to be as follows: Proteus mirabilis (16), Escherichia coli (7), Providencia spp. (7), Proteus spp. (2), P. vulgaris (3), Shigella sp. (1), Citrobacter freundii (1), and Acinetobacter sp. (1). Their class 2 integron cassette arrays were amplified and then either analyzed using PCR-RFLP or sequenced. The typical array dfrA1-sat2-aadA1 was detected in 27 isolates. Six atypical arrays were observed, including three kinds of novel arrangements (linF2(∆attC1)-dfrA1(∆attC2)-aadA1-orf441 or linF2(∆attC1)-dfrA1(∆attC2)-aadA1, dfrA1-catB2-sat2-aadA1, and estX(Vr)-sat2-aadA1) and a hybrid with the 3'CS of class 1 integrons (dfrA1-sat2-aadA1-qacH), and dfrA1-sat1. Twenty-four isolates were also found to carry class 1 integrons with 10 types of gene cassette arrays. Several non-integron-associated antibiotic resistance genes were found, and their transferability was investigated. Results showed that water sources in the Jinan region harbored a diverse community of both typical and atypical class 2 integrons, raising concerns about the overuse of antibiotics and their careless disposal into the environment.201323264021
1373150.9875Multidrug resistant Aeromonas spp. isolated from zebrafish (Danio rerio): antibiogram, antimicrobial resistance genes and class 1 integron gene cassettes. Aeromonas spp. are Gram-negative opportunistic bacteria which have been commonly associated with fish diseases. In this study, antibiogram, antimicrobial resistance genes and integrons of 43 zebrafish-borne Aeromonas spp. were studied. The isolates were identified as six Aeromonas species (A. veronii biovar veronii (n = 26), A. veronii biovar sobria (n = 3), A. hydrophila (n = 8), A. caviae (n = 3), A. enteropelogenes (n = 2) and A. dhakensis (n = 1)). Antibiogram of the isolates indicated that most of them were resistant to amoxicillin (100·00%), nalidixic acid (100·00%), oxytetracycline (100·00%), ampicillin (93·02%), tetracycline (74·42%), rifampicin (67·44%) and imipenem (65·15%). Multiple antimicrobial resistance (MAR) index values ranged from 0·19-0·44 to 90·70% isolates showed multidrug resistance. PCR of antimicrobial resistance genes revealed that the tetracycline resistance gene (tetA) was the most predominant (67·44%) among the isolates. The qnrS (53·49%), tetB (30·23%), tetE (30·23%), qnrB (23·26%) and aac(6')-Ib-cr (4·65%) genes were also detected. Class 1 integrase (IntI1) gene was found in 46·51% of the isolates. Two types of class 1 integron gene cassette profiles (qacG-aadA6-qacG and drfA1) were identified. The results showed that zebrafish-borne aeromonads can harbour different types of antimicrobial resistance genes and class 1 integrons. SIGNIFICANCE AND IMPACT OF THE STUDY: Aeromonas spp. are important pathogens found in diverse environments. Antimicrobial resistance genes and integrons of ornamental fish-borne Aeromonas spp. are not well studied. The antibiogram, antimicrobial resistance genes and class 1 integrons of Aeromonas spp. isolated from zebrafish were characterized for the first time in Korea. The prevalence of tetracycline resistance genes, plasmid-mediated quinolone resistance genes and class 1 integron gene cassettes were observed among the isolates. The qacG-aadA6-qacG gene cassette was identified for the first time in Aeromonas spp. The results suggest that the wise use of antimicrobials is necessary for the better management of the ornamental fish.201930790321
1296160.9874Prevalence and antimicrobial resistance of Salmonellaisolates from goose farms in Northeast China. BACKGROUND: Salmonella is one of the most important enteric pathogenic bacteria that threatened poultry health. AIMS: This study aimed to investigate the prevalence and antimicrobial resistance of Salmonella isolates in goose farms. METHODS: A total of 244 cloacal swabs were collected from goose farms to detect Salmonella in Northeast China. Antimicrobial susceptibility, and resistance gene distribution of Salmonella isolates were investigated. RESULTS: Twenty-one Salmonella isolates were identified. Overall prevalence of Salmonella in the present study was 8.6%. Among the Salmonella isolates, the highest resistance frequencies belonged to amoxicillin (AMX) (85.7%), tetracycline (TET) and trimethoprim/sulfamethoxazole (SXT) (81%), followed by chloramphenicol (CHL) (76.2%), florfenicol (FLO) (71.4%), kanamycin (KAN) (47.6%), and gentamycin (GEN) (38.1%). Meanwhile, only 4.8% of the isolates were resistant to ciprofloxacin (CIP) and cefotaxime (CTX). None of the isolates was resistant to cefoperazone (CFP) and colistin B (CLB). Twenty isolates (95%) were simultaneously resistant to at least two antimicrobials. Ten resistance genes were detected among which the bla (TEM-1), cmlA, aac(6')-Ib-cr, sul1, sul2, sul3, and mcr-1.1 were the most prevalent, and presented in all 21 isolates followed by tetB (20/21), qnrB (19/21), and floR (15/21). CONCLUSION: Results indicated that Salmonella isolates from goose farms in Northeast China exhibited multi-drug resistance (MDR), harboring multiple antimicrobial resistance genes. Our results will be useful to design prevention and therapeutic strategies against Salmonella infection in goose farms.202033584841
2769170.9874Occurrences and Characterization of Antibiotic-Resistant Bacteria and Genetic Determinants of Hospital Wastewater in a Tropical Country. Wastewater discharged from clinical isolation and general wards at two hospitals in Singapore was examined to determine the emerging trends of antibiotic resistance (AR). We quantified the concentrations of 12 antibiotic compounds by analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS), antibiotic-resistant bacteria (ARB), the class 1 integrase gene (intI1), and 16 antibiotic resistance genes (ARGs) that confer resistance to 10 different clinically relevant antibiotics. A subset of 119 antibiotic-resistant isolates were phylogenetically classified and tested for the presence of ARGs encoding resistance to β-lactam antibiotics (bla(NDM), bla(KPC), bla(SHV), bla(CTX-M)), amikacin [aac(6')-Ib], co-trimoxazole (sul1, sul2, dfrA), ciprofloxacin (qnrA, qnrB), and the intI1 gene. Among these resistant isolates, 80.7% were detected with intI1 and 66.4% were found to carry at least 1 of the tested ARGs. Among 3 sampled locations, the clinical isolation ward had the highest concentrations of ARB and the highest levels of ARGs linked to resistance to β-lactam (bla(KPC)), co-trimoxazole (sul1, sul2, dfrA), amikacin [aac(6')-Ib], ciprofloxacin (qnrA), and intI1 We found strong positive correlations (P < 0.05) between concentrations of bacteria resistant to meropenem, ceftazidime, amikacin, co-trimoxazole, and ciprofloxacin and abundances of bla(KPC), aac(6')-Ib, sul1, sul2, dfrA, qnrA, and intI1 genes.201627736769
1372180.9874Incidence of antimicrobial resistance genes and class 1 integron gene cassettes in multidrug-resistant motile Aeromonas sp. isolated from ornamental guppy (Poecilia reticulata). Aeromonas sp. are opportunistic pathogenic bacteria which are associated with various diseases in ornamental fish, aquaculture raised species and wild fisheries. In our study, antimicrobial resistance patterns, antimicrobial resistance genes and class 1 integron gene cassettes of 52 guppy-borne Aeromonas sp. were examined. The isolates were identified as A. veronii (n = 34), A. dhakensis (n = 10), A. hydrophila (n = 3), A. caviae (n = 3) and A. enteropelogenes (n = 2) by gyrB gene sequencing. Every isolate was resistant to at least four antimicrobials in disc diffusion test. The resistance to amoxicillin, nalidixic acid and oxytetracycline was 100% among the tested isolates. 92·30, 76·92, 71·15, 51·92, 51·92 and 50·00% of the isolates were resistant to ampicillin, rifampicin, imipenem, cephalothin, tetracycline and trimethoprim respectively. The multiple antibiotic resistance index values ranged from 0·28 to 0·67. PCR amplification of antimicrobial resistance genes implied the occurrence of tetracycline resistance (tetA (65·39%), tetE (25·00%) and tetB (15·38%)), plasmid-mediated quinolone resistance (qnrS (26·92%) and qnrB (17·31%)) and aminoglycoside resistance (aphaAI-IAB (7·69%) and aac (6')-Ib (3·84%)) genes in the isolates. The IntI gene was positive for 36·54% of the isolates and four class 1 integron gene cassette profiles (aadA2, qacE2-orfD, aadA2-catB2 and dfrA12-aadA2) were identified. These data suggest that ornamental guppy can be a reservoir of multidrug-resistant Aeromonas sp. which comprise different antimicrobial resistance genes and class 1 integrons. SIGNIFICANCE AND IMPACT OF THE STUDY: Antimicrobial resistance genes and integron gene cassettes of ornamental fish-borne aeromonads are poorly studied. The antimicrobial resistance patterns, antimicrobial resistance genes and class 1 integron gene cassettes of Aeromonas sp. isolated from ornamental guppy were characterized for the first time in Korea. The incidence of different antimicrobial resistance genes and class 1 integron gene cassettes were observed in multidrug-resistant Aeromonas isolates. This result suggests that better management practices are necessary to prevent and address the serious consequences of indiscriminate and inappropriate antimicrobial use, and the distribution of multidrug-resistant bacteria.201930980564
1236190.9873Molecular characterization of antimicrobial resistance in Gram-negative bacteria isolated from bovine mastitis in Egypt. The aim of this study was to characterize the genetic basis of multidrug resistance in Gram-negative bacteria isolated from bovine mastitis cases in Egypt. Multidrug resistance phenotypes were found in 34 of 112 (30.4%) Gram-negative bacterial isolates, which harbored at least one antimicrobial resistance gene. The most prevalent multidrug-resistant (MDR) species were Enterobacter cloacae (8 isolates, 7.1%), Klebsiella pneumoniae (7 isolates, 6.3%), Klebsiella oxytoca (7 isolates, 6.3%), Escherichia coli (5 isolates, 4.5%), and Citrobacter freundii (3 isolates, 2.7%). The most commonly observed resistance phenotypes were against ampicillin (97.0%), streptomycin (94.1%), tetracycline (91.2%), trimethoprim-sulfamethoxazole (88.2%), nalidixic acid (85.3%), and chloramphenicol (76.5%). Class 1 integrons were detected in 28 (25.0%) isolates. The gene cassettes within class 1 integrons included those encoding resistance to trimethoprim (dfrA1, dfrA5, dfrA7, dfrA12, dfrA15, dfrA17, and dfrA25), aminoglycosides (aadA1, aadA2, aadA5, aadA7, aadA12, aadA22, and aac(3)-Id), chloramphenicol (cmlA), erythromycin (ereA2), and rifampicin (arr-3). Class 2 integrons were identified in 6 isolates (5.4%) with three different profiles. Furthermore, the β-lactamase encoding genes, bla(TEM), bla(SHV), bla(CTX-M), and bla(OXA), the plasmid-mediated quinolone resistance genes, qnr and aac(6)-Ib-cr, and the florfenicol resistance gene, floR, were also identified. To the best of our knowledge, the results identified class 2 integrons, qnr and aac(6)-Ib-cr from cases of mastitis for the first time. This is the first report of molecular characterization for antimicrobial resistance in Gram-negative bacteria isolated from bovine mastitis in Africa.201121338385