# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 2957 | 0 | 1.0000 | Characteristics of High-Level Aminoglycoside-Resistant Enterococcus faecalis Isolated from Bulk Tank Milk in Korea. Enterococci, which are considered environmental mastitis-causing pathogens, have easily acquired aminoglycoside-resistant genes that encode various aminoglycoside-modifying enzymes (AME). Therefore, this study was conducted to compare the distribution of high-level aminoglycoside-resistant (HLAR) and multidrug-resistant (MDR) Enterococcus faecalis (E. faecalis) bacteria isolated from bulk tank milk in four dairy companies in Korea. Moreover, it analyzed the characteristics of their antimicrobial resistance genes and virulence factors. Among the 301 E. faecalis bacteria studied, 185 (61.5%) showed HLAR with no significant differences among the dairy companies. Furthermore, 129 (69.7%) of the 185 HLAR E. faecalis showed MDR without significant differences among companies. In contrast, HLAR E. faecalis from companies A, B, and C were significantly higher in resistance to the four classes than those in company D, which had the highest MDR ability against the three antimicrobial classes (p < 0.05). In addition, in the distribution of AME genes, 72 (38.9%) and 36 (19.5%) of the isolates carried both aac(6')Ie-aph(2″)-la and ant(6)-Ia genes, and the ant (6)-Ia gene alone, respectively, with significant differences among the companies (p < 0.05). In the distribution of virulence genes, the ace (99.5%), efa A (98.9%), and cad 1 (98.4%) genes were significantly prevalent (p < 0.05). Thus, our results support that an advanced management program by companies is required to minimize the dissemination of antimicrobial resistance and virulence factors. | 2021 | 34207875 |
| 2398 | 1 | 0.9999 | Antimicrobial-Resistant Enterococcus spp. in Wild Avifauna from Central Italy. Bacteria of the genus Enterococcus are opportunistic pathogens, part of the normal intestinal microflora of animals, able to acquire and transfer antimicrobial resistance genes. The aim of this study was to evaluate the possible role of wild avifauna as a source of antimicrobial-resistant enterococci. To assess this purpose, 103 Enterococcus spp. strains were isolated from the feces of wild birds of different species; they were tested for antimicrobial resistance against 21 molecules, vancomycin resistance, and high-level aminoglycosides resistance (HLAR). Furthermore, genes responsible for vancomycin, tetracycline, and HLAR were searched. E. faecium was the most frequently detected species (60.20% of isolates), followed by E. faecalis (34.95% of isolates). Overall, 99.02% of the isolated enterococci were classified as multidrug-resistant, with 19.41% extensively drug-resistant, and 2.91% possible pan drug-resistant strains. Most of the isolates were susceptible to amoxicillin/clavulanic acid (77.67%) and ampicillin (75.73%), with only 5.83% of isolates showing an ampicillin MIC ≥ 64 mg/L. HLAR was detected in 35.92% of isolates, mainly associated with the genes ant(6)-Ia and aac(6')-Ie-aph(2″)-Ia. Few strains (4.85%) were resistant to vancomycin, and the genes vanA and vanB were not detected. A percentage of 54.37% of isolates showed resistance to tetracycline; tet(M) was the most frequently detected gene in these strains. Wild birds may contribute to the spreading of antimicrobial-resistant enterococci, which can affect other animals and humans. Constant monitoring is essential to face up to the evolving antimicrobial resistance issue, and monitoring programs should include wild avifauna, too. | 2022 | 35884106 |
| 2399 | 2 | 0.9998 | Ready-to-eat dairy products as a source of multidrug-resistant Enterococcus strains: Phenotypic and genotypic characteristics. The enterococci are ubiquitous bacteria able to colonize the human and animal gastrointestinal tracts and fresh and fermented food products. Their highly plastic genome allows Enterococcus spp. to gain resistance to multiple antibiotics, making infections with these organisms difficult to treat. Food-borne enterococci could be carriers of antibiotic resistance determinants. The goal of this work was to study the characteristics of Enterococcus spp. in fermented milk products from Poland and their antibiotic resistance gene profiles. A total of 189 strains were isolated from 182 dairy products out of 320 samples tested. The predominant species were Enterococcus faecium (53.4%) and Enterococcus faecalis (34.4%). Isolates were resistant to streptomycin (29.1%), erythromycin (14.3%), tetracycline (11.6%), rifampicin (8.7%), and tigecycline (8.1%). We also detected 2 vancomycin-resistant and 3 linezolid-resistant strains; however, no vanA or vanB genes were identified. A total of 57 high-level aminoglycoside resistance strains (30.2%) were identified, most of which have the ant(6')-Ia gene, followed by the aac(6')-Ie-aph(2″)-Ia and aph(3″)-IIIa genes. Resistance to tetracycline was most often conferred by tetM and tetL genes. Macrolide resistance was most frequently encoded by ermB and ermA genes. Conjugative mobile genetic element (transposon Tn916-Tn1545) was identified in 15.3% of the strains, including 96.3% of strains harboring the tetM gene. This study found that enterococci are widely present in retail ready-to-eat dairy products in Poland. Many isolated strains are antibiotic resistant and carry transferable resistance genes, which represent a potential source of transmission of multidrug-resistant bacteria to humans. | 2020 | 32197843 |
| 2671 | 3 | 0.9998 | Toxinotyping and molecular characterization of antimicrobial resistance in Clostridium perfringens isolated from different sources of livestock and poultry. The present study was designed to understand the presence of antimicrobial resistance among the prevalent toxinotypes of Clostridium perfringens recovered from different animals of Tamil Nadu, India. A total of 75 (10.76%) C. perfringens were isolated from 697 multi-species fecal and intestinal content samples. C. perfringens type A (90.67%), type C (2.67%), type D (4%) and type F (2.67%) were recovered. Maximum number of isolates were recovered from dog (n = 20, 24.10%) followed by chicken (n = 19, 5.88%). Recovered isolates were resistant to gentamicin (44.00%), erythromycin (40.00%), bacitracin (40.00%), and tetracycline (26.67%), phenotypically and most of the isolates were found to be resistant to multiple antimicrobials. Genotypic characterization revealed that tetracycline (41.33%), erythromycin (34.66%) and bacitracin (17.33%) resistant genes were present individually or in combination among the isolates. Combined results of phenotypic and genotypic characterization showed the highest percentage of erythromycin resistance (26.66%) among the isolates. None of the isolates showed amplification for lincomycin resistance genes. The correlation matrix analysis of genotypic resistance showed a weak positive relationship between the tetracycline and bacitracin resistance while a weak negative relationship between the tetracycline and erythromycin resistance. The present study thus reports the presence of multiple-resistance genes among C. perfringens isolates that may be involved in the dissemination of resistance to other bacteria present across species. Further insights into the genome can help to understand the mechanism involved in gene transfer so that measures can be taken to prevent the AMR spread. | 2021 | 33220406 |
| 1363 | 4 | 0.9998 | Comparison of antimicrobial resistance and molecular characterization of Escherichia coli isolates from layer breeder farms in Korea. In Korea, 4 big layer companies that possess one grandparent and 3 parent stocks are in charge of 100% of the layer chicken industry. In this study, we investigated the antimicrobial resistance of commensal 578 E. coli isolated from 20 flocks of 4-layer breeder farms (A, B, C, and D), moreover, compared the characteristics of their resistance and virulence genes. Isolates from farms B and D showed significantly higher resistance to the β-lactam antimicrobials (amoxicillin, ampicillin, and 1st-, 2nd-, and 3rd-generation cephalosporins). However, resistance to ciprofloxacin, nalidixic acid, and tetracycline was significantly higher in the isolates from farm A (P < 0.05). Interestingly, the isolates from farm C showed significantly lower resistance to most antimicrobials tested in this study. The isolates from farms B, C, and D showed the high multiple resistance to the 3 antimicrobial classes. Furthermore, the isolates from farm A showed the highest multiple resistance against the 5 classes. Among the 412 β-lactam-resistant isolates, 123 (29.9%) carried bla(TEM-1), but the distribution was significantly different among the farms from 17.5% to 51.4% (P < 0.05). Similarly, the most prevalent tetracycline resistance gene in the isolates from farms B, C, and D was tetA (50.0-77.0%); however, the isolates from farm A showed the highest prevalence in tetB (70.6%). The distribution of quinolone (qnrB, qnrD, and qnrS) and sulfonamide (su12)-resistant genes were also significantly different among the farms but that of chloramphenicol (catA1)- and aminoglycoside (aac [3]-II, and aac [6']-Ib)-resistant genes possessed no significant difference among the farms. Moreover, the isolates from farm C showed significantly higher prevalence in virulence genes (iroN, ompT, hlyF, and iss) than the other 3 farms (P < 0.05). Furthermore, the phenotypic and genotypic characteristics of E. coli isolates were significantly different among the farms, and improved management protocols are required to control of horizontal and vertical transmission of avian disease, including the dissemination of resistant bacteria in breeder flocks. | 2022 | 34844113 |
| 2397 | 5 | 0.9998 | Antimicrobial resistance in Enterococcus strains isolated from healthy domestic dogs. Enterococci are opportunistic bacteria that cause severe infections in animals and humans, capable to acquire, express, and transfer antimicrobial resistance. Susceptibility to 21 antimicrobial agents was tested by the disk diffusion method in 222 Enterococcus spp. strains isolated from the fecal samples of 287 healthy domestic dogs. Vancomycin and ampicillin minimum inhibitory concentrations (MICs) and high-level aminoglycoside resistance (HLAR) tests were also performed. Isolates showed resistance mainly to streptomycin (88.7%), neomycin (80.6%), and tetracycline (69.4%). Forty-two (18.9%) isolates showed an HLAR to streptomycin and 15 (6.7%) to gentamicin. Vancomycin and ampicillin MIC values showed 1 and 18 resistant strains, respectively. One hundred and thirty-six (61.2%) strains were classified as multidrug resistant and six (2.7%) strains as possibly extensively drug-resistant bacteria. Enterococcus faecium and Enterococcus faecalis were the most prevalent antimicrobial resistant species. Companion animals, which often live in close contact with their owners and share the same environment, represent a serious source of enterococci resistant to several antibiotics; for this reason, they may be a hazard for public health by providing a conduit for the entrance of resistance genes into the community. | 2017 | 27976593 |
| 2719 | 6 | 0.9998 | Antimicrobial resistance and virulence signatures of Listeria and Aeromonas species recovered from treated wastewater effluent and receiving surface water in Durban, South Africa. BACKGROUND: Treated wastewater effluent has been found to contain high levels of contaminants, including disease-causing bacteria such as Listeria and Aeromonas species. The aim of this study was to evaluate the antimicrobial resistance and virulence signatures of Listeria and Aeromonas spp. recovered from treated effluents of two wastewater treatment plants and receiving rivers in Durban, South Africa. METHODS: A total of 100 Aeromonas spp. and 78 Listeria spp. were positively identified based on biochemical tests and PCR detection of DNA region conserved in these genera. The antimicrobial resistance profiles of the isolates were determined using Kirby Bauer disc diffusion assay. The presence of important virulence genes were detected via PCR, while other virulence determinants; protease, gelatinase and haemolysin were detected using standard assays. RESULTS: Highest resistance was observed against penicillin, erythromycin and nalidixic acid, with all 78 (100%) tested Listeria spp displaying resistance, followed by ampicillin (83.33%), trimethoprim (67.95%), nitrofurantoin (64.10%) and cephalosporin (60.26%). Among Aeromonas spp., the highest resistance (100%) was observed against ampicillin, penicillin, vancomycin, clindamycin and fusidic acid, followed by cephalosporin (82%), and erythromycin (58%), with 56% of the isolates found to be resistant to naladixic acid and trimethoprim. Among Listeria spp., 26.92% were found to contain virulence genes, with 14.10, 5.12 and 21% harbouring the actA, plcA and iap genes, respectively. Of the 100 tested Aeromonas spp., 52% harboured the aerolysin (aer) virulence associated gene, while lipase (lip) virulence associated gene was also detected in 68% of the tested Aeromonas spp. CONCLUSIONS: The presence of these organisms in effluents samples following conventional wastewater treatment is worrisome as this could lead to major environmental and human health problems. This emphasizes the need for constant evaluation of the wastewater treatment effluents to ensure compliance to set guidelines. | 2015 | 26498595 |
| 2932 | 7 | 0.9998 | Resistance to Sulfonamides and Dissemination of sul Genes Among Salmonella spp. Isolated from Food in Poland. Antimicrobial resistance of pathogenic bacteria, including Salmonella spp., is an emerging problem of food safety. Antimicrobial use can result in selection of resistant organisms. The food chain is considered a route of transmission of resistant pathogens to humans. In many European countries, sulfonamides are one of the most commonly used antimicrobials. The aim of our investigation was to assess the prevalence of sul genes and plasmid occurrence among sulfonamide-resistant Salmonella spp. Eighty-four sulfonamide-resistant isolates were collected in 2008 and 2013 from retail products in Poland. Minimal inhibitory concentration of all of these isolates was ≥1024 μg/mL. Resistant isolates were tested for the presence of sul1, sul2, sul3, and int1 genes by using multiplex polymerase chain reaction. In total, 44.0% (37/84) isolates carried the sul1 gene, 46.4% (39/84) were sul2 positive, while the sul3 gene was not detected in any of the sulfonamide-resistant isolates tested. It was found that 3.6% (3/84) of resistant Salmonella spp. contained sul1, sul2, and intI genes. All 33 intI-positive isolates carried the sul1 gene. Eleven of the sulfonamide-resistant isolates were negative for all the sul genes. Most of the sulfonamide-resistant Salmonella spp. harbored plasmids; only in eight isolates were no plasmids detected. Generally, the size of the plasmids ranged from approximately 2 kb to ≥90 kb. Our results revealed a relatively a high prevalence of sulfonamides-resistant Salmonella spp. isolated from retail food. Additionally, we have detected a high dissemination of plasmids and class 1 integrons that may enhance the spread of resistance genes in the food chain. | 2015 | 25785781 |
| 2903 | 8 | 0.9998 | Soil 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. | 2021 | 34887843 |
| 1362 | 9 | 0.9998 | Distribution of phenotypic and genotypic antimicrobial resistance and virulence genes in Vibrio parahaemolyticus isolated from cultivated oysters and estuarine water. A total of 594 Vibrio parahaemolyticus isolates from cultivated oysters (n = 361) and estuarine water (n = 233) were examined for antimicrobial resistance (AMR) phenotype and genotype and virulence genes. Four hundred forty isolates (74.1%) exhibited resistance to at least one antimicrobial agent and 13.5% of the isolates were multidrug-resistant strains. Most of the V. parahaemolyticus isolates were resistant to erythromycin (54.2%), followed by sulfamethoxazole (34.7%) and trimethoprim (27.9%). The most common resistance genes were qnr (77.8%), strB (27.4%) and tet(A) (22.1%), whereas blaTEM (0.8%) was rarely found. Four isolates (0.7%) from oysters (n = 2) and estuarine water (n = 2) were positive to tdh, whereas no trh-positive isolates were observed. Significantly positive associations among AMR genes were observed. The SXT elements and class 1, 2 and 3 integrons were absent in all isolates. The results indicated that V. parahaemolyticus isolates from oysters and estuarine water were potential reservoirs of resistance determinants in the environment. This increasing threat of resistant bacteria in the environment potentially affects human health. A 'One Health' approach involved in multidisciplinary collaborations must be implemented to effectively manage antimicrobial resistance. | 2020 | 32358958 |
| 2956 | 10 | 0.9998 | Genomic Characterization of Enterococcus hirae From Beef Cattle Feedlots and Associated Environmental Continuum. Enterococci are commensal bacteria of the gastrointestinal tract of humans, animals, and insects. They are also found in soil, water, and plant ecosystems. The presence of enterococci in human, animal, and environmental settings makes these bacteria ideal candidates to study antimicrobial resistance in the One-Health continuum. This study focused on Enterococcus hirae isolates (n = 4,601) predominantly isolated from beef production systems including bovine feces (n = 4,117, 89.5%), catch-basin water (n = 306, 66.5%), stockpiled bovine manure (n = 24, 0.5%), and natural water sources near feedlots (n = 145, 32%), and a few isolates from urban wastewater (n = 9, 0.2%) denoted as human-associated environmental samples. Antimicrobial susceptibility profiling of a subset (n = 1,319) of E. hirae isolates originating from beef production systems (n = 1,308) showed high resistance to tetracycline (65%) and erythromycin (57%) with 50.4% isolates harboring multi-drug resistance, whereas urban wastewater isolates (n = 9) were resistant to nitrofurantoin (44.5%) and tigecycline (44.5%) followed by linezolid (33.3%). Genes for tetracycline (tetL, M, S/M, and O/32/O) and macrolide resistance erm(B) were frequently found in beef production isolates. Antimicrobial resistance profiles of E. hirae isolates recovered from different environmental settings appeared to reflect the kind of antimicrobial usage in beef and human sectors. Comparative genomic analysis of E. hirae isolates showed an open pan-genome that consisted of 1,427 core genes, 358 soft core genes, 1701 shell genes, and 7,969 cloud genes. Across species comparative genomic analysis conducted on E. hirae, Enterococcus faecalis and Enterococcus faecium genomes revealed that E. hirae had unique genes associated with vitamin production, cellulose, and pectin degradation, traits which may support its adaptation to the bovine digestive tract. E. faecium and E. faecalis more frequently harbored virulence genes associated with biofilm formation, iron transport, and cell adhesion, suggesting niche specificity within these species. | 2022 | 35832805 |
| 2918 | 11 | 0.9998 | Antibiotic resistance genes in multidrug-resistant Enterococcus spp. and Streptococcus spp. recovered from the indoor air of a large-scale swine-feeding operation. AIMS: In this study, multidrug-resistant bacteria previously recovered from the indoor air of a large-scale swine-feeding operation were tested for the presence of five macrolide, lincosamide and streptogramin (MLS) resistance genes and five tetracycline (tet) resistance genes. METHODS AND RESULTS: Enterococcus spp. (n = 16) and Streptococcus spp. (n =16) were analysed using DNA-DNA hybridization, polymerase chain reaction (PCR) and oligoprobing of PCR products. All isolates carried multiple MLS resistance genes, while 50% of the Enterococcus spp. and 44% of the Streptococcus spp. also carried multiple tet resistance genes. All Enterococcus spp. carried erm(A) and erm(B), 69% carried erm(F), 44% carried mef(A), 75% carried tet(M), 69% carried tet(L) and 19% carried tet(K). All Streptococcus spp. carried erm(B), 94% carried erm(F), 75% carried erm(A), 38% carried mef(A), 50% carried tet(M), 81% carried tet(L) and 13% carried tet(K). CONCLUSIONS: Multidrug resistance among airborne bacteria recovered from a swine operation is encoded by multiple MLS and tet resistance genes. These are the first data regarding resistance gene carriage among airborne bacteria from swine-feeding operations. SIGNIFICANCE AND IMPACT OF THE STUDY: The high prevalence of multiple resistance genes reported here suggests that airborne Gram-positive bacteria from swine operations may be important contributors to environmental reservoirs of resistance genes. | 2006 | 17032228 |
| 2693 | 12 | 0.9998 | Prevalence, Antimicrobial Resistance and Toxin-Encoding Genes of Clostridioides difficile from Environmental Sources Contaminated by Feces. Clostridioides difficile (C. difficile) is the most common pathogen causing antibiotic-associated intestinal diseases in humans and some animal species, but it can also be present in various environments outside hospitals. Thus, the objective of this study was to investigate the presence and the characteristics of toxin-encoding genes and antimicrobial resistance of C. difficile isolates from different environmental sources. C. difficile was found in 32 out of 81 samples (39.50%) after selective enrichment of spore-forming bacteria and in 45 samples (55.56%) using a TaqMan-based qPCR assay. A total of 169 C. difficile isolates were recovered from those 32 C. difficile-positive environmental samples. The majority of environmental C. difficile isolates were toxigenic, with many (88.75%) positive for tcdA and tcdB. Seventy-four isolates (43.78%) were positive for binary toxins, cdtA and cdtB, and 19 isolates were non-toxigenic. All the environmental C. difficile isolates were susceptible to vancomycin and metronidazole, and most isolates were resistant to ciprofloxacin (66.86%) and clindamycin (46.15%), followed by moxifloxacin (13.02%) and tetracycline (4.73%). Seventy-five isolates (44.38%) showed resistance to at least two of the tested antimicrobials. C. difficile strains are commonly present in various environmental sources contaminated by feces and could be a potential source of community-associated C. difficile infections. | 2023 | 36671363 |
| 2909 | 13 | 0.9998 | Determination 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. | 2006 | 16330169 |
| 2931 | 14 | 0.9998 | Molecular characterization of antibiotic resistance in Escherichia coli strains from a dairy cattle farm and its surroundings. BACKGROUND: This study describes the phenotypic and genotypic characteristics of 78 genetically different Escherichia coli recovered from air and exudate samples of a dairy cattle farm and its surroundings in Spain, in order to gain insight into the flow of antimicrobial resistance through the environment and food supply. RESULTS: Antimicrobial resistance was detected in 21.8% of the 78 E. coli isolates analyzed (resistance for at least one of the 14 agents tested). The highest resistance rates were recorded for ampicillin, nalidixic acid, trimethoprim/sulfamethoxazole and tetracycline. The resistance genes detected were as follows (antibiotic (number of resistant strains), gene (number of strains)): ampicillin (9), bla(TEM-1) (6); tetracycline (15), tet(A) (7), tet(B) (4), tet(A) + tet(B) (1); chloramphenicol (5), cmlA (2), floR (2); trimethoprim/sulfamethoxazole (10), sul2 (4), sul1 (3), sul3 (2), sul1 + sul2 (1); gentamicin-tobramycin (1), ant(2″) (1). About 14% of strains showed a multidrug-resistant phenotype and, of them, seven strains carried class 1 integrons containing predominantly the dfrA1-aadA1 array. One multidrug-resistant strain was found in both inside and outside air, suggesting that the airborne spread of multidrug-resistant bacteria from the animal housing facilities to the surroundings is feasible. CONCLUSIONS: This study gives a genetic background of the antimicrobial resistance problem in a dairy cattle farm and shows that air can act as a source for dissemination of antimicrobial-resistant bacteria. © 2016 Society of Chemical Industry. | 2017 | 26969806 |
| 2681 | 15 | 0.9998 | Determination of the Prevalence and Antimicrobial Resistance of Enterococcus faecalis and Enterococcus faecium Associated with Poultry in Four Districts in Zambia. The presence of antimicrobial-resistant Enterococci in poultry is a growing public health concern worldwide due to its potential for transmission to humans. The aim of this study was to determine the prevalence and patterns of antimicrobial resistance and to detect drug-resistant genes in Enterococcus faecalis and E. faecium in poultry from four districts in Zambia. Identification of Enterococci was conducted using phenotypic methods. Antimicrobial resistance was determined using the disc diffusion method and antimicrobial resistance genes were detected using polymerase chain reaction and gene-specific primers. The overall prevalence of Enterococci was 31.1% (153/492, 95% CI: 27.1-35.4). Enterococcus faecalis had a significantly higher prevalence at 37.9% (58/153, 95% CI: 30.3-46.1) compared with E. faecium, which had a prevalence of 10.5% (16/153, 95% CI: 6.3-16.7). Most of the E. faecalis and E. faecium isolates were resistant to tetracycline (66/74, 89.2%) and ampicillin and erythromycin (51/74, 68.9%). The majority of isolates were susceptible to vancomycin (72/74, 97.3%). The results show that poultry are a potential source of multidrug-resistant E. faecalis and E. faecium strains, which can be transmitted to humans. Resistance genes in the Enterococcus species can also be transmitted to pathogenic bacteria if they colonize the same poultry, thus threatening the safety of poultry production, leading to significant public health concerns. | 2023 | 37107019 |
| 2670 | 16 | 0.9998 | Molecular characterisation and antimicrobial resistance of Streptococcus agalactiae isolates from dairy farms in China. INTRODUCTION: Streptococcus agalactiae (S. agalactiae) is a pathogen causing bovine mastitis that results in considerable economic losses in the livestock sector. To understand the distribution and drug resistance characteristics of S. agalactiae from dairy cow mastitis cases in China, multilocus sequence typing (MLST) was carried out and the serotypes and drug resistance characteristics of the bacteria in the region were analysed. MATERIAL AND METHODS: A total of 21 strains of bovine S. agalactiae were characterised based on MLST, molecular serotyping, antimicrobial susceptibility testing, and the presence of drug resistance genes. RESULTS: The serotypes were mainly Ia and II, accounting for 47.6% and 42.9% of all serotypes, respectively. Five sequence types (STs) were identified through MLST. The ST103 and ST1878 strains were predominant, with rates of 52.4% and 28.6%, respectively. The latter is a novel, previously uncharacterised sequence type. More than 90% of S. agalactiae strains were susceptible to penicillin, oxacillin, cephalothin, ceftiofur, gentamicin, florfenicol and sulfamethoxazole. The bacteria showed high resistance to tetracycline (85.7%), clindamycin (52.1%) and erythromycin (47.6%). Resistant genes were detected by PCR, the result of which showed that 47.6%, 33.3% and 38.1% of isolates carried the tet(M), tet(O) and erm(B) genes, respectively. CONCLUSION: The results of this study indicate that S. agalactiae show a high level of antimicrobial resistance. It is necessary to monitor the pathogens of mastitis to prevent the transmission of these bacteria. | 2023 | 38143824 |
| 2400 | 17 | 0.9998 | Antimicrobial susceptibility and distribution of antimicrobial-resistance genes among Enterococcus and coagulase-negative Staphylococcus isolates recovered from poultry litter. Data on the prevalence of antimicrobial resistant enterococci and staphylococci from the poultry production environment are sparse in the United States. This information is needed for science-based risk assessments of antimicrobial use in animal husbandry and potential public-health consequences. In this study, we assessed the susceptibility of staphylococci and enterococci isolated from poultry litter, recovered from 24 farms across Georgia, to several antimicrobials of veterinary and human health importance. Among the 90 Enterococcus isolates recovered, E. hirae (46%) was the most frequently encountered species, followed by E. faecium (27%), E. gallinarum (12%), and E. faecalis (10%). Antimicrobial resistance was most often observed to tetracycline (96%), followed by clindamycin (90%), quinupristin-dalfopristin (62%), penicillin (53%), erythromycin (50%), nitrofurantoin (49%), and clarithromycin (48%). Among the 110 staphylococci isolates recovered, only coagulase-negative staphylococci (CNS) were identified with the predominant Staphylococcus species being S. sciuri (38%), S. lentus (21%), S. xylosus (14%) and S. simulans (12%). Resistance was less-frequently observed among the Staphylococcus isolates for the majority of antimicrobials tested, as compared with Enterococcus isolates, and was primarily limited to clarithromycin (71%), erythromycin (71%), clindamycin (48%), and tetracycline (38%). Multidrug resistance (MDR) phenotypes were prevalent in both Enterococcus and Staphylococcus; however, Enterococcus exhibited a statistically significant difference in the median number of antimicrobials to which resistance was observed (median = 5.0) compared with Staphylococcus species (median = 3.0). Because resistance to several of these antimicrobials in gram-positive bacteria may be attributed to the shuttling of common drug-resistance genes, we also determined which common antimicrobial-resistance genes were present in both enterococci and staphylococci. The antimicrobial resistance genes vat(D) and erm(B) were present in enterococci, vgaB in staphylococci, and mobile genetic elements Tn916 and pheromone-inducible plasmids were only identified in enterococci. These data suggest that the disparity in antimicrobial-resistance phenotypes and genotypes between enterococci and staphylococci isolated from the same environment is, in part, because of barriers preventing exchange of mobile DNA elements. | 2007 | 18251398 |
| 2910 | 18 | 0.9998 | Phenotypic and genotypic characterization of tetracycline and minocycline resistance in Clostridium perfringens. The aim of this study was to determine the incidence of tetracycline resistance and the prevalence of tetracycline-resistance genes in strains of Clostridium perfringens isolated from different sources between 1994 and 2005. Susceptibility to tetracycline and minocycline in strains from humans (35 isolates), chickens (15 isolates), food (21 isolates), soil (16 isolates) and veterinary sources (6 isolates) was determined, and tetracycline-resistance genes were detected. Resistance was most common in strains isolated from chickens, followed by those from soils, clinical samples and foods. The most highly resistant strains were found among clinical and food isolates. tetA(P) was the most common resistance gene, and along with tetB(P) was found in all resistant strains and some sensitive strains. One tetracycline-resistant food isolate had an intact tet(M) gene. However, PCR fragments of 0.4 or 0.8 kb with high degrees of identity to parts of the tet(M) sequences of other bacteria were found, mainly in clinical isolates, and often in isolates with tetB(P). No correlation between level of sensitivity to tetracycline or minocycline and the presence of tetA(P), tetB(P) or part of tet(M) was found. The presence of part of tet(M) in some strains of C. perfringens containing tetB(P) may have occurred by recent gene transfer. | 2010 | 20661548 |
| 2358 | 19 | 0.9998 | Genotypic and Phenotypic Evaluation of Biofilm Production and Antimicrobial Resistance in Staphylococcus aureus Isolated from Milk, North West Province, South Africa. Background: Biofilm formation in S. aureus may reduce the rate of penetration of antibiotics, thereby complicating treatment of infections caused by these bacteria. The aim of this study was to correlate biofilm-forming potentials, antimicrobial resistance, and genes in S. aureus isolates. Methods: A total of 64 milk samples were analysed, and 77 S. aureus were isolated. Results: Seventy (90.9%) isolates were biofilm producers. The ica biofilm-forming genes were detected among 75.3% of the isolates, with icaA being the most prevalent (49, 63.6%). The icaB gene was significantly (P = 0.027) higher in isolates with strong biofilm formation potentials. High resistance (60%-90%) of the isolates was observed against ceftriaxone, vancomycin, and penicillin, and 25 (32.5%) of S. aureus showed multidrug resistance (MDR) to at least three antibiotics. Five resistance genes, namely blaZ (29, 37.7%), vanC (29, 37.7%), tetK (24, 31.2%), tetL (21, 27.3%), and msrA/B (16, 20.8%) were detected. Most MDR phenotypes possessed at least one resistance gene alongside the biofilm genes. However, no distinct pattern was identified among the resistance and biofilm phenotypes. Conclusions: The high frequency of potentially pathogenic MDR S. aureus in milk samples intended for human consumption, demonstrates the public health relevance of this pathogen in the region. | 2020 | 32252278 |