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544900.9928Antibiotic susceptibility and resistance genes profiles of Vagococcus salmoninarum in a rainbow trout (Oncorhyncus mykiss, Walbaum) farm. Disease outbreaks negatively affect fish production. Antimicrobial agents used in the treatment of diseases become ineffective over time because of antibiotic resistance developed by bacteria distributed in the aquaculture environment. This study was conducted for 4 months (cold period) in a fish farm to detect the fish disease, cold water streptococcosis. In the study, four brood stock showing disease signs were detected. Bacteria isolates were obtained and identified as Vagococcus salmoninarum. Antimicrobial susceptibility of V. salmoninarum was tested and antibiotic resistance gene profiles of V. salmoninarum isolates were screened. The phylogenetic relation of the isolates with the previously reported strains was evaluated. Antibiotic resistance developed by pathogenic bacteria is distributed in the aquaculture environment. The transfer of resistance genes from one bacterium to another is very common. This situation causes the antimicrobial agents used in the treatment of diseases to become ineffective over time. The disc diffusion test showed that all four isolates developed resistance to 13 (FFC30, AX25, C30, E15, CF30, L2, OX1, S10, T30, CRO30, CC2, PT15 and TY15) of the evaluated antibiotics and were about to develop resistance to six others (AM 10, FM 300, CFP75, SXT25, APR15 and TE30). Furthermore, antibiotic resistance genes tetA, sul1, sul2, sul3, dhfr1, ereB and floR were detected in the isolated strain. Moreover, the phylogenetic analysis showed that isolated V. salmoninarum strain (ESN1) was closely related to the bacterial strains isolated from USA and Jura.202438560471
299510.9927Antibiotic resistance in bacteria from magpies (Pica pica) and rabbits (Oryctolagus cuniculus) from west Wales. The prevalence of antibiotic-resistant bacteria in wild animal and bird populations is largely unknown, with little consistency among the few published reports. We therefore examined intestinal bacteria from magpies (Pica pica) and rabbits (Oryctolagus cuniculus) collected in rural west Wales. Escherichia coli isolates resistant to multiple antibiotics were grown from eight of 20 magpies trapped in spring, 1999 and one of 17 in spring, 2000; the most prevalent resistance trait among these isolates was to tetracycline, but resistances to ampicillin, chloramphenicol, kanamycin, sulphonamide, tetracycline and trimethoprim were also found. Tetracycline-resistant Enterococcus spp. were found in one of 20 magpies in 1999 and three of 17 in 2000. Only one resistant E. coli isolate was detected among gut bacteria from 13 rabbits, and this strain was resistant only to tetracycline. Differences in the prevalence of resistance between bacteria from rabbits and magpies may reflect differences in diet: rabbits graze field edges, whereas magpies are omnivorous and opportunistic. The resistance genes found in E. coli isolates from magpies mostly corresponded to those common among human isolates, but those conferring tetracycline resistance were unique.200111722546
267420.9924Phylogeny, virulence factors and antimicrobial susceptibility of Escherichia coli isolated in clinical bovine mastitis. The aim of this study was to identify specific phylogeny groups, virulence genes or antimicrobial resistance traits of Escherichia coli isolated in bovine mastitis associated to clinical signs, persistence of intramammary infection in the quarter and recovery from mastitis. A total of 154 E. coli isolates from bovine clinical mastitis, 144 from the acute stage and 10 from follow-up samples 3 weeks later, originating from 144 cows in 65 dairy herds in Southern Finland were investigated. Phylogeny groups and virulence genes of the isolates were determined using polymerase chain reaction, and antimicrobial susceptibility using the VetMIC™ microdilution method. In ten cows (11.8%), infection persisted, confirmed by re-isolation of the same pulsed-field gel electrophoresis type from the affected quarter at 3 weeks post-treatment. The majority of isolates, 119 (82.6%), belonged to phylogeny group A, which mainly consisted of commensal strains. Altogether 56 isolates (38.9%) had at least one virulence gene detected. Most common virulence genes detected were irp2, iucD, papC iss; genes svg, stx1, stx2, cnf1 and hlyA were not found. Combinations of virulence genes varied greatly. Forty (27.8%) of the 144 E. coli isolates showed resistance to at least one antimicrobial tested. None of the studied phylogeny groups, virulence factors or antimicrobial resistance traits was associated with clinical signs, persistence of intramammary infection or clinical recovery from mastitis. The results support the conclusion that mastitis-causing E. coli bacteria are typical commensals.201120729012
279130.9924Molecular characterization, antibiotic resistant pattern and biofilm forming potentiality of bacterial community associated with Ompok pabda fish farming in southwestern Bangladesh. Ompok pabda is gaining popularity in the aquaculture industry due to its increasing demand; however research on microbial diversity and antibiotic susceptibility remains limited. The present study was designed to identify the bacterial pathogens commonly found in the pabda farming system with their biofilm forming potential and antibiotic susceptibility. Different bacterial strains were isolated from water, sediments and gut, gill of pabda fish and the isolates were identified based on their morphological traits, biochemical and molecular analysis. Antibiotic susceptibilities, antibiotic resistance gene determination and biofilm formation capabilities were evaluated by disc diffusion method, PCR amplification and Microtiter plate (MTP) assay, respectively. The respective isolates of gill and gut of pabda aquaculture and their environments were: Exiguobacterium spp. (25 %), Enterococcus spp. (20 %), Bacillus spp. (10 %), Acinetobacter spp. (10 %), Enterobacter spp. (10 %), Aeromonas spp. (10 %), Lactococcus spp. (5 %), Klebsiella spp. (5 %) and Kurthia spp. (5 %). Antibiotic resistance frequencies were found to be relatively high, especially for trimethoprim (95 %), sulfafurazole (75 %), ampicillin (60 %), amoxicillin-clavulanic acid (55 %), and cephradine (50 %). 30 % isolates were categorized as DR bacteria followed by 30 % isolates were MDR bacteria and 40 % were classified as XDR bacteria. Moreover, 4 antibiotic resistant genes were detected with sul1 (30 %), dfrA1 (10 %), tetC (40 %), and qnrA (5 %) of isolates. Based on the microtiter plate method, 20 %, 25 %, and 30 % of isolates were found to produce strong, moderate, and weak biofilms, respectively. The findings suggest that biofilm forming bacterial strains found in O. pabda fish farm may be a potential source of numerous antibiotic-resistant bacteria. The study sheds new light on antibiotic resistance genes, which are typically inherited by bacteria and play an important role in developing effective treatments or control strategies.202439047804
544740.9924Antimicrobial Drug-resistance Profile of Vibrio Parahaemolyticus isolated from Japanese Horse Mackerel (Trachurus Japonicus). This study aimed at investigating antimicrobial resistance (AMR) profile of Vibrio parahaemolyticus (V. parahaemolyticus). The bacteria were isolated from wild-caught and farmed Japanese horse mackerel (Trachurus japonicus), and examined for the antimicrobial drug resistance. Furthermore, the serotype, and the genes of thermostable direct hemolysin (tdh) and cholera toxin transcriptional activator (toxR) of the isolates were investigated by using a serotype testing kit and PCR method. Eighty-eight and 126 V. parahaemolyticus strains were isolated from wild-caught and farmed Japanese horse mackerel, respectively. Ten and 18 distinct serotypes were detected from wild-caught and farmed Japanese horse mackerel. All strains were negative for tdh genes but positive for toxR genes. Resistances to ampicillin (ABP) and to both ABP and fosfomycin (FOM) were observed in 54 and 23 strains from the wild-caught fish, while those resistant strains from farm fish were 112 and 7 strains. Multidrug-resistance to three or four drugs including ABP was observed in one or two strains from the wild-caught fish. These results strongly suggest that the environmental exposure of antimicrobial drugs results in the spread of resistant genes in Japanese horse mackerel. This study highlights the need for monitoring the spread of resistance genes to the human intestinal flora as well as to other bacteria in the environment.202134631335
248750.9923Clinical cases, drug resistance, and virulence genes profiling in Uropathogenic Escherichia coli. Uropathogenic Escherichia coli (UPEC) as the most important bacterial agent of urinary tract infections (UTIs) encompasses a wide treasure of virulence genes and factors. In due to this default, the aim of this research was to detect and identify some important virulence genes including cnf1, upaH, hlyA, ibeA, and cdtB in isolated UPEC pathotypes. In this research, clinical samples of urine were collected in Shahr-e-Qods, Tehran, Iran. The UPEC pathotypes were confirmed by standard biochemical tests. The DNAs of isolated bacteria were extracted. The genes of cnf1, upaH, hlyA, ibeA, and cdtB were run for multiplex PCR and gel electrophoresis. Furthermore, the antibiogram was done for the isolated UPEC strains by 11 common antibiotics. In accordance with the results, the virulence genes of cnf1, upaH, hlyA, ibeA, and cdtB were respectively recognized in 100%, 51.2%, 38.4%, 9.3%, and 0% of isolated UPEC pathotypes. In consequence, the final virulence gene profiling of the isolated UPEC strains was patterned as cnf1, cnf1-upaH, cnf1-upaH-hlyA, and cnf1-upaH-hlyA-ibeA. The chi-square tests showed no significant correlations between virulence gene profile and UTIs, between virulence gene profile and antibiotic resistance, and between virulence genes and different types of UTIs. The cnf1 virulence gene contributes in the occurrence of all types of UTIs. In contrast to cnf1, the cdtB gene was absent in the isolated UPEC strains in this investigation. The most ineffective antibiotics were recognized as Penicillin, Tetracycline, and Nalidixic acid, respectively, while Streptomycin, Chloramphenicol, and Ciprofloxacin are the best options for UTIs treatment.202031950434
134160.9923Campylobacter jejuni from no antibiotics ever (NAE) broilers: prevalence, antibiotic resistance, and virulence genes analysis. Campylobacter jejuni (C. jejuni) is a leading foodborne illness causing bacteria, and poultry is a major reservoir of this pathogen. With the recent increase in broiler production under the "no antibiotics ever" (NAE) system, this study aimed to assess the prevalence, antibiotic resistance, and virulence characteristics of C. jejuni isolated from NAE raised broilers. A total of 270 cloacal swabs were collected from the live-hang areas of 3 commercial processing plants over 9 wk. Each processing plant was visited 3 times at a 1-wk interval, and 30 samples were collected per visit. Among the total 270 cloacal swab samples, C. jejuni was isolated from 44 (16.3%) samples . Of these isolates, 65.9% possessed toxin-producing genes cdtA, cdtB, and cdtC, and invasion gene ciaB. The prevalence of antibioitc resistance genes aph (3')-IIIa, erm(B) were 59.1%, and 50%, respectively. Nine (20.45%) C. jejuni isolates were identified as multidrug resistant (MDR), and 18 (40.9%) isolates showed resistance to at least 1 tested antibiotic. The highest resistance was observed against tetracycline (29.5%), followed by nalidixic acid (25%), whereas 22.7% of isolates were resistant to 2 clinically important antibiotics, azithromycin and ciprofloxacin. These results suggest that there ishigh prevalence level of multi-drug resistant C. jejuni with toxin producing virulence genes in the NAE-raised broilers sampled in this study, indicating the potential for serious human illnesses if transmitted through the food chain.202439418794
288070.9923Antibiotic resistance monitoring in heterotrophic bacteria from anthropogenic-polluted seawater and the intestines of oyster Crassostrea hongkongensis. A total of 1,050 strains of heterotrophic bacteria isolated from farming seawater and the intestines of oyster species Crassostrea hongkongensis were tested for resistance to 10 antibiotics by the Kirby-Bauer diffusion method. The resistant rates of seawater-derived bacteria to chloramphenicol, enrofloxacin, and ciprofloxacin were low (less than 20%), whereas the bacteria obtained from oysters showed low resistance to chloramphenicol and enrofloxacin. Many strains showed high resistant rates (more than 40%) to furazolidone, penicillin G, and rifampin. A total of 285 strains from farming seawater and oysters were resistant to more than three antibiotics. Several strains showed resistance to more than nine antibiotics. Furthermore, the peak resistant rates of the seawater-derived strains to multiple antibiotics overlapped in April, June, September, and November, and those of oyster-derived strains overlapped during April, July, and September. The multi-resistant rate patterns of strains from farming seawater and oyster intestines were similar.201425133348
549580.9923Virulent and Multi-drug-Resistant Edwardsiella tarda Infection in Oscar Fish: Unveiling the Threat of Mass Mortality and AMR Dissemination. The Oscar fish (Astronotus ocellatus) is among the most commonly domesticated and exported ornamental fish species from Kerala. The ornamental fish industry faces a significant challenge with the emergence of diseases caused by multi-drug-resistant bacteria. In the present study, six isolates were resolved from the diseased Oscar fish showing haemorrhages, necrosis, and loss of pigmentation. After phenotypic and genotypic characterization, the bacteria were identified as Edwardsiella tarda, Klebsiella pneumoniae, Enterococcus faecalis, Escherichia coli, Brevibacillus borstelensis, and Staphylococcus hominis. Experimental challenge studies in healthy Oscar fish showed that E. tarda caused 100% mortality within 240 h with 6.99 × 10(6) CFU/fish as LD(50) and histopathology revealed the typical signs of infection. The pathogen was re-recovered from the moribund fish thereby confirming Koch's postulates. E. tarda was confirmed through the positive amplification of tarda-specific gene and virulence genes viz., etfD and escB were also detected using PCR. Antibiotic susceptibility tests using disc diffusion displayed that the pathogen is multi-drug-resistant towards antibiotics belonging to aminoglycosides, tetracyclines, and quinolones categories with a MAR index of 0.32, which implicated the antibiotic pressure in the farm. Plasmid curing studies showed a paradigm shift in the resistance pattern with MAR index of 0.04, highlighting the resistance genes are plasmid-borne except for the chromosome-borne tetracycline resistance gene (tetA). This study is the first of its kind in detecting mass mortality caused by E. tarda in Oscar fish. Vigilant surveillance and strategic actions are crucial for the precise detection of pathogens and AMR in aquaculture.202438753164
133990.9922Helicobacter pylori in a poultry slaughterhouse: Prevalence, genotyping and antibiotic resistance pattern. Although Helicobacter pylori (H. pylori) is a highly significant pathogen, its source remains unclear. Many people consume chicken daily as a source of animal protein worldwide; thus, hygienic methods of supplying chickens for consumption are critical for public health. Therefore, our study examined the distribution of the glmM (ureC), babA2, vacA and cagA virulence genes in H. pylori strains in chicken meat and giblets (gizzards and livers) and the resistance of the strains to various antibiotics. Ninety chicken meat, gizzard and liver samples were obtained from a semi-automatic abattoir in Sadat City, Egypt, and were cultured and preliminarily analyzed using biochemical tests. The presence of the ureC, babA2, vacA and cagA genotypes was tested for in samples positive for H. pylori by multiplex polymerase chain reaction (Multiplex-PCR). The resistance of H. pylori to various antimicrobial drugs was tested using the disc diffusion method. In total, 7 of the 90 chicken samples were positive for H. pylori (7.78%); in 3/7 (42.85%) samples, the bacteria were found in the chicken liver, while the bacteria were found in the meat in 2/7 (28.57%) and in the gizzard in 2/7 (28.57%) samples. The total prevalence of both the ureC and babA2 genes in the isolated H. pylori strains was 100%, while the prevalence of the vacA and cagA genes was 57.1% and 42.9%, respectively. The resistance of H. pylori to the antibiotics utilized in our study was 100% for streptomycin; 85.7% for amoxicillin and penicillin; 71.4% for oxytetracycline, nalidixic acid and ampicillin; 57.1% for sulfamethoxazole and erythromycin; and 42.9% for neomycin, chloramphenicol and norfloxacin. In conclusion, the chicken meat and giblets were tainted by H. pylori, with a higher occurrence of the ureC, babA2, vacA and cagA genotypes. Future investigations should investigate the resistance of H. pylori to various antimicrobial agents in Egypt.201830174504
1380100.9922Distribution 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
2708110.9922Occurrence, Virulence and Antimicrobial Resistance-Associated Markers in Campylobacter Species Isolated from Retail Fresh Milk and Water Samples in Two District Municipalities in the Eastern Cape Province, South Africa. Campylobacter species are among the major bacteria implicated in human gastrointestinal infections and are majorly found in faeces of domestic animals, sewage discharges and agricultural runoff. These pathogens have been implicated in diseases outbreaks through consumption of contaminated milk and water in some parts of the globe and reports on this is very scanty in the Eastern Cape Province. Hence, this study evaluated the occurrence as well as virulence and antimicrobial-associated makers of Campylobacter species recovered from milk and water samples. A total of 56 water samples and 72 raw milk samples were collected and the samples were processed for enrichment in Bolton broth and incubated for 48 h in 10% CO(2) at 42 °C under microaerobic condition. Thereafter, the enriched cultures were further processed and purified. After which, presumptive Campylobacter colonies were isolated and later confirmed by PCR using specific primers for the detection of the genus Campylobacter, target species and virulence associated genes. Antimicrobial resistance profiles of the isolates were determined by disk diffusion method against a panel of 12 antibiotics and relevant genotypic resistance genes were assessed by PCR assay. A total of 438 presumptive Campylobacter isolates were obtained; from which, 162 were identified as belonging to the genus Campylobacter of which 36.92% were obtained from water samples and 37.11% from milk samples. The 162 confirmed isolates were further delineated into four species, of which, 7.41%, 27.16% and 8.64% were identified as C. fetus, C. jejuni and C. coli respectively. Among the virulence genes screened for, the iam (32.88%) was most prevalent, followed by flgR (26.87%) gene and cdtB and cadF (5.71% each) genes. Of the 12 antibiotics tested, the highest phenotypic resistance displayed by Campylobacter isolates was against clindamycin (95.68%), while the lowest was observed against imipenem (21.47%). Other high phenotypic resistance displayed by the isolates were against erythromycin (95.06%), followed by ceftriaxone (93.21%), doxycycline (87.65%), azithromycin and ampicillin (87.04% each), tetracycline (83.33%), chloramphenicol (78.27%), ciprofloxacin (77.78%), levofloxacin (59.88%) and gentamicin (56.17%). Relevant resistance genes were assessed in the isolates that showed high phenotypic resistance, and the highest resistance gene harbored by the isolates was catII (95%) gene while VIM, KPC, Ges, bla-(OXA)-48-like, tetC, tetD, tetK, IMI and catI genes were not detected. The occurrence of this pathogen and the detection of virulence and antimicrobial resistance-associated genes in Campylobacter isolates recovered from milk/water samples position them a risk to human health.202032708075
1317120.9922Antibiotic resistance and virulence genes profile of Non typhodial Salmonella species isolated from poultry enteritis in India. Salmonella species (spp) is the most important gastrointestinal pathogen present ubiquitously. Non typhoidal Salmonella (NTS) is commonly associated with gastroenteritis in humans. Layer birds once get infection with NTS, can become persistently infected with Salmonella Typhimurium and intermittently shed the bacteria. It results in a high risk of potential exposure of eggs to the bacteria. The current study was conducted to determine the serotype diversity, presence of virulence genes, antibiotic resistance pattern, and genes of NTS from poultry enteritis. Out of 151 intestinal swabs from poultry total 118 NTS were isolated, which were characterized serologically as S. Typhimurium (51 strains), S. Weltevreden (57 strains) and untypable (10 strains). Most effective antibiotics were amikacin, gentamycin and ceftriaxone (33.05%) followed by ampicillin, azithromycin and ciprofloxacin (16.69%), co-trimoxazole (13.55%), and tetracycline (6.78%). Multidrug resistance recorded in 17.70% (N = 21/118) strains. Antimicrobial-resistant genes i.e. blaTEM, blaSHV, blaCTX-M, tet(A), tet(B), tet(C), sul1, sul2, sul3. blaTEM and tet(A) were present in 95% (20/21). Eleven virulence genes i.e. invA, hilA, sivH, tolC, agfA, lpfA, spaN, pagC, spiA, iroN and fliC 2 were present in all the 30 isolates. While, sopE was present in only 2 isolates, NTS strains with characteristics of pathogenicity and multidrug resistance from poultry enteritis were detected. Multidrug resistance showed the necessity of prudent use of antibiotics in the poultry industry.202438430331
5278130.9922Antibiotic resistance of culturable heterotrophic bacteria isolated from shrimp (Penaeus vannamei) aquaculture ponds. Shrimp aquaculture is one of the fastest growing food-producing avenues, where antibiotics usage has become an issue of great concern due to the development of antimicrobial resistance in bacteria. A total of 2304 bacterial isolates from 192 samples (sediment, water, shrimp, and source water) from Andhra Pradesh, India were screened. Antibiotic resistance of bacterial isolates was highest for oxytetracycline (23.4%) followed by erythromycin (12.7%), co-trimoxazole (10%) ciprofloxacin (9.6%), and chloramphenicol (6%), of which 11.9% isolates were multi-drug resistant. Bacterial isolates from shrimp (26.7%), water (23.9%), and sediment (19.6%) samples exhibited more resistance (p ≤ 0.05) towards oxytetracycline. Higher antibacterial resistance was observed from samples of southern Andhra Pradesh (locations L6 and L7). Gram negative bacteria were more prevalent (64%) and showed significantly (p ≤ 0.01) higher resistance. This study indicated the wider distribution of antibiotic-resistant bacteria in shrimp aquaculture ponds with potential risk to humans and the environment.202134450408
2409140.9922Prevalence and Antimicrobial Resistance of Listeria monocytogenes in Different Raw Food from Reynosa, Tamaulipas, Mexico. Listeria (L.) monocytogenes is an opportunistic foodborne pathogen that causes listeriosis in humans and animals, reaching up to 30% case mortality. There are only a few reports in Mexico about the L. monocytogenes strains found in various foods. The aim of this study was to determine the prevalence of L. monocytogenes, serogroups, virulence genes, and antimicrobial resistance in different foods from Reynosa, Tamaulipas, Mexico. L. monocytogenes strains were characterized by microbiological and molecular methods. Susceptibility to 12 antibiotics was determined according to CLSI and EUCAST. A total of 300 samples of seafood, pasteurized and raw milk, cheese, beef, and chicken were collected from supermarkets and retail markets. The presence of L. monocytogenes was detected in 5.6% of the samples. Most strains belonged to serogroups 4b, 4d, and 4e (68.4%). All strains presented a minimum of four virulence genes; the most common were actA, hly, and plcB (92.1%). A high percentage of antimicrobial susceptibility was observed, with resistance only to STX-TMP (78.9%), STR (26.3%), MEM (21.0%), and E (2.6%). These results show that the foods in Reynosa, Tamaulipas, are a reservoir of L. monocytogenes and represent a potential health risk.202438890883
1370150.9922Risk Characterization of Antibiotic Resistance in Bacteria Isolated from Backyard, Organic, and Regular Commercial Eggs. This study was conducted to assess the risk due to antimicrobial-resistant strains of Salmonella spp., Listeria monocytogenes, and Escherichia coli isolated from the eggshell and the contents of eggs bought in markets in Valencia (Spain). Thirty-four samples from three different production styles were analyzed: standard ( n = 34), organic ( n = 16), and backyard ( n = 10) eggs. L. monocytogenes was not isolated in any style of production. Only one strain of Salmonella was isolated from standard production, which was resistant to ciprofloxacin and amoxicillin. E. coli strains were resistant in 22% of the isolates from organic production, 12.25% from standard production, and 11.23% from backyard production. In all cases, the highest resistance was observed for amoxicillin-clavulanate. None of the isolates from standard and backyard eggs were resistant to chloramphenicol, ciprofloxacin, gentamycin, and streptomycin, while only ceftriaxone was found to be effective against all E. coli isolates from organic eggs. β-Lactamase genes bla(TEM) , bla(SHV), and bla(CMY-2) and the resistance genes for tetracycline tetA, tetB, and tetC were tested. The most commonly detected antimicrobial resistance genes among the E. coli isolates were tetA (49.30%), bla(TEM) (47.89%), and tetB (36.62%). Overall, a maximum public health risk is associated with β-lactam antibiotics.201930794464
1366160.9922Day-old chicks are a source of antimicrobial resistant bacteria for laying hen farms. Antimicrobial resistant bacteria are rarely detected in laying hens and the objective of this longitudinal study was to test day-old chick as a source. Four different commercial batches raised on the same farm were monitored from day-old chick to laying hens using Escherichia coli as a model. Ten colonies from each of the eight samplings per batch were tested for antimicrobial susceptibility using 14 antimicrobials. Overall (313 isolates), higher resistance percentages were detected for tetracycline (26.8%), followed by sulphonamides (16.3%), ampicillin (16.0%) and quinolones (10.9% and 9.3% for ciprofloxacin and nalidixic acid, respectively). Resistance percentages of bacteria from day-old chicks were higher than those of pullets and hens (p < 0.05) for tetracycline, sulphonamides, trimethoprim and chloramphenicol. Forty different phenotypic resistance profiles were detected, led by fully susceptible (182 isolates; 58.1%), and followed by single tetracycline (28 isolates; 8.9%) and ciprofloxacin/ nalidixic acid (11 isolates; 3.5%) profiles. By whole-genome sequencing, 17 genes and mutations of five chromosomal genes related to resistance were detected, the most frequent being tetA, bla(TEM-1B) and sul1. Using multilocus sequencing analysis, 58 different MLST types were detected, most of them only in a particular sample. The ST155 (27/142) was the most frequently detected, followed by ST10 (19/142) and ST48 (9/142). The fate on the farm of the detected E. coli populations in old-day chicks was not clear, but our data suggest that they did not remain in the predominant faecal population of pullets and laying hens.201930827391
2799170.9922Genetic and physiological characterization of oxytetracycline-resistant bacteria from giant prawn farms. Four hundred and thirteen oxytetracycline-resistant bacteria were recovered from six freshwater giant prawn farms with a history of oxytetracycline use. Most oxytetracyclineresistant isolates were Gram-negative bacteria. Six groups of oxytetracycline-resistant bacteria were classified using cluster analysis based on a comparison of levels of oxytetracycline resistance. Complex fingerprint patterns were obtained for 71 isolates studied. In general, the band patterns of isolates from different ponds were very similar, and the data indicated that the isolates were closely related. The exploration for crossresistance found that most of the 71 oxytetracycline-resistant isolates were also resistant to tetracycline and chlortetracycline, but had a relatively low resistance to doxycycline. Many isolates showed higher chlortetracycline resistance than oxytetracycline resistance. Additionally, the oxytetracyclineresistant isolates were examined for the presence of tetracycline resistance (tet) genes. Fifty percent of the isolates carried one of the 14 known tet genes examined. The most common determinants were TetA and TetD. However, TetB, TetC, TetE, TetK, TetL, and TetM were also found with various frequencies.200818309262
5386180.9921Antibiotic resistance of lactic acid bacteria isolated from Chinese yogurts. The aim of this study was to evaluate the susceptibility of 43 strains of lactic acid bacteria, isolated from Chinese yogurts made in different geographical areas, to 11 antibiotics (ampicillin, penicillin G, roxithromycin, chloramphenicol, tetracycline, chlortetracycline, lincomycin, kanamycin, streptomycin, neomycin, and gentamycin). The 43 isolates (18 Lactobacillus bulgaricus and 25 Streptococcus thermophilus) were identified at species level and were typed by random amplified polymorphic DNA analysis. Thirty-five genotypically different strains were detected and their antimicrobial resistance to 11 antibiotics was determined using the agar dilution method. Widespread resistance to ampicillin, chloramphenicol, chlortetracycline, tetracyclines, lincomycin, streptomycin, neomycin, and gentamycin was found among the 35 strains tested. All of the Strep. thermophilus strains tested were susceptible to penicillin G and roxithromycin, whereas 23.5 and 64.7% of Lb. bulgaricus strains, respectively, were resistant. All of the Strep. thermophilus and Lb. bulgaricus strains were found to be resistant to kanamycin. The presence of the corresponding resistance genes in the resistant isolates was investigated through PCR, with the following genes detected: tet(M) in 1 Lb. bulgaricus and 2 Strep. thermophilus isolates, ant(6) in 2 Lb. bulgaricus and 2 Strep. thermophilus isolates, and aph(3')-IIIa in 5 Lb. bulgaricus and 2 Strep. thermophilus isolates. The main threat associated with these bacteria is that they may transfer resistance genes to pathogenic bacteria, which has been a major cause of concern to human and animal health. To our knowledge, the aph(3')-IIIa and ant(6) genes were found in Lb. bulgaricus and Strep. thermophilus for the first time. Further investigations are required to analyze whether the genes identified in Lb. bulgaricus and Strep. thermophilus isolates might be horizontally transferred to other species.201222916881
1364190.9921Antimicrobial resistance patterns of Shiga toxin-producing Escherichia coli O157:H7 and O157:H7- from different origins. Shiga toxin-producing Escherichia coli (STEC) serotypes including O157:H7 (n = 129) from dairy cows, cull dairy cow feces, cider, salami, human feces, ground beef, bulk tank milk, bovine feces, and lettuce; and O157:H7- (n = 24) isolated from bovine dairy and bovine feedlot cows were evaluated for antimicrobial resistance against 26 antimicrobials and the presence of antimicrobial resistance genes (tetA, tetB, tetC, tetD, tetE, tetG, floR, cmlA, strA, strB, sulI, sulII, and ampC). All E. coli exhibited resistance to five or more antimicrobial agents, and the majority of isolates carried one or more target antimicrobial resistance gene(s) in different combinations. The majority of E. coli showed resistance to ampicillin, aztreonam, cefaclor, cephalothin, cinoxacin, and nalidixic acid, and all isolates were susceptible to chloramphenicol and florfenicol. Many STEC O157:H7 and O157:H7-isolates were susceptible to amikacin, carbenicillin, ceftriaxone, cefuroxime, ciprofloxacin, fosfomycin, moxalactam, norfloxacin, streptomycin, tobramycin, trimethoprim, and tetracycline. The majority of STEC O157:H7 (79.8%) and O157:H7- (91.7%) carried one or more antimicrobial resistance gene(s) regardless of whether phenotypically resistant or susceptible. Four tetracycline resistant STEC O157:H7 isolates carried both tetA and tetC. Other tetracycline resistance genes (tetB, tetD, tetE, and tetG) were not detected in any of the isolates. Among nine streptomycin resistant STEC O157:H7 isolates, eight carried strA-strB along with aadA, whereas the other isolate carried aadA alone. However, the majority of tetracycline and streptomycin susceptible STEC isolates also carried tetA and aadA genes, respectively. Most ampicillin resistant E. coli of both serotypes carried ampC genes. Among sulfonamide resistance genes, sulII was detected only in STEC O157:H7 (4 of 80 sulfonamide-resistant isolates) and sulI was detected in O157:H7- (1 of 16 sulfonamide resistant isolates). The emergence and dissemination of multidrug resistance in STEC can serve as a reservoir for different antimicrobial resistance genes. Dissemination of antimicrobial resistance genes to commensal and pathogenic bacteria could occur through any one of the horizontal gene transfer mechanisms adopted by the bacteria.200717536933