# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 1226 | 0 | 0.9717 | Multi-drug resistant gram-negative enteric bacteria isolated from flies at Chengdu Airport, China. We collected flies from Chengdu Shuangliu International Airport to examine for the presence of bacteria and to determine the sensitivity patterns of those bacteria. A total of 1,228 flies were collected from 6 sites around Chengdu Shuangliu International Airport from April to September 2011. The predominant species was Chrysomya megacephala (n=276, 22.5%). Antimicrobial-resistant gram-negative enteric bacteria (n=48) were isolated from flies using MacConkey agar supplemented with cephalothin (20 microg/ml). These were identified as Escherichia coli (n=37), Klebsiella pneumoniae (n=6), Pseudomonas aeruginosa (n=3) and Aeromonas hydrophila (n=2). All isolated bacteria were tested for resistance to 21 commonly used antimicrobials: amoxicillin (100%), ticarcillin (100%), cephalothin (100%), cefuroxime (100%), ceftazidime 1 (93.8%), piperacillin (93.8%), cefotaxime (89.6%), ticarcillin-clavulanate (81.3%), trimethoprim-sulfamethoxazole (62.5%), ciprofloxacin (54.2%), gentamicin (45.8%), cefepime (39.6%), tobramycin (39.6%), ceftazidime (22.9%), cefoxitin (16.7%), amikacin (16.7%), netilmicin (14.6%), amoxicillin-clavulanate (6.3%) and piperacillin-tazobactam (2.1%). No resistance to meropenem or imipenem was observed. Antibiotic resistance genes among the isolated bacteria were analyzed for by polymerase chain reaction. Thirty of the 48 bacteria with resistance (62.5%) possessed the blaTEM gene. | 2013 | 24450236 |
| 1227 | 1 | 0.9713 | Antibiotic resistance among coliform bacteria isolated from carcasses of commercially slaughtered chickens. A total of 322 coliform bacteria Escherichia coli, Enterobacter spp., Citrobacter spp., Klebsiella spp. and Serratia spp., were isolated from 50 carcasses of commercially slaughtered chickens. Their resistance to ampicillin, tetracycline, gentamicin, chloramphenicol, cephalotine, cotrimoxazole, nalidixic acid and nitrofurantoin, were determined. The most commonly found resistance was to tetracycline followed by cephalotine, cotrimoxazole and nalidixic acid. A large percentage of E. coli (41%) and Klebsiella spp. (38%) showed multiple antibiotic resistance. | 1990 | 2282290 |
| 1299 | 2 | 0.9713 | Prevalence, Drug Resistance, and Virulence Genes of Potential Pathogenic Bacteria in Pasteurized Milk of Chinese Fresh Milk Bar. Fresh Milk Bar (FMB), an emerging dairy retail franchise, is used to instantly produce and sell pasteurized milk and other dairy products in China. However, the quality and safety of pasteurized milk in FMB have received little attention. The objective of this study was to investigate the prevalence, antimicrobial resistance, and virulence genes of Escherichia coli, Staphylococcus aureus, and Streptococcus in 205 pasteurized milk samples collected from FMBs in China. Four (2.0%) isolates of E. coli, seven (3.4%) isolates of S. aureus, and three (1.5%) isolates of Streptococcus agalactiae were isolated and identified. The E. coli isolates were resistant to amikacin (100%), streptomycin (50%), and tetracycline (50%). Their detected resistance genes include aac(3)-III (75%), blaTEM (25%), aadA (25%), aac(3)-II (25%), catI (25%), and qnrB (25%). The S. aureus isolates were mainly resistant to penicillin G (71.4%), trimethoprim-sulfamethoxazole (71.4%), kanamycin (57.1%), gentamicin (57.1%), amikacin (57.1%), and clindamycin (57.1%). blaZ (42.9%), mecA (28.6%), ermB (14.3%), and ermC (14.3%) were detected as their resistance genes. The Streptococcus strains were mainly resistant to tetracycline (66.7%) and contained the resistance genes pbp2b (33.3%) and tetM (33.3%). The virulence genes eae and stx2 were only found in one E. coli strain (25%), sec was detected in two S. aureus strains (28.6%), and bca was detected in one S. agalactiae strain (33.3%). The results of this study indicate that bacteria with drug resistance and virulence genes isolated from the pasteurized milk of FMB are a potential risk to consumers' health. | 2021 | 34129676 |
| 1329 | 3 | 0.9709 | First report of the Staphylococcus aureus isolate from subclinical bovine mastitis in the South of Brazil harboring resistance gene dfrG and transposon family Tn916-1545. The aim of this work was to identify at the molecular level the species of coagulase-positive staphylococci isolates from clinical and subclinical bovine mastitis samples in Southern Brazil, and to evaluate the antimicrobial resistance profile, as well as the presence of resistance genes. According to the PCR assay, all 31 isolates were classified as Staphylococcus aureus. The isolates were tested for resistance to penicillin, ampicillin, oxacillin, cefoxitin, cephalothin, ceftiofur, streptomycin, tobramycin, teicoplanin, erythromycin, clindamycin, enrofloxacin, sulfonamide, trimethoprim-sulfamethoxazole, trimethoprim, and tetracycline by the disk diffusion method. Most of the isolates were resistant to sulfonamide (20), followed by ampicillin and clindamycin (16). Twenty isolates were multidrug-resistant. PCR was used for the detection of several antimicrobial resistance genes (ereB, ermB, ermC, tetA, tetB, tetK, tetL, tetM, tetO, Tn916-1545, strA, strB, sul1, sul2, dfrA, dfrG, dfrK, blaZ, mecA, and mecC). The most prevalent antimicrobial resistance genes were tetK and tetL, ereB, followed by tetM, Tn916-1545 and blaZ, detected in 11, nine and four isolates, respectively. For all the tetM gene positive isolates, the presence of conjugative transposons of the Tn916-1545 family was detected. The presence of multidrug-resistant isolates, antimicrobial resistance genes and transposons suggests a potential risk of spreading multi-resistance genes to other bacteria. | 2017 | 29051059 |
| 1259 | 4 | 0.9708 | Tetracycline resistance potential of heterotrophic bacteria isolated from freshwater fin-fish aquaculture system. AIMS: This study investigated the tetracycline resistance potential of heterotrophic bacteria isolated from twenty-four freshwater fin-fish culture ponds in Andhra Pradesh, India. METHODS AND RESULTS: A total of 261 tetracycline resistant bacteria (tetR) were recovered from pond water, pond sediment, fish gills, fish intestine, and fish feed. Bacteria with high tetracycline resistance (tetHR) (n = 30) that were resistant to tetracycline concentrations above 128 μg mL-1 were predominantly Lactococcus garvieae followed by Enterobacter spp., Lactococcus lactis, Enterobacter hormaechei, Staphylococcus arlettae, Streptococcus lutetiensis, Staphylococcus spp., Brevundimonas faecalis, Exiguobacterium profundum, Lysinibacillus spp., Stutzerimonas stutzeri, Enterobacter cloacae, and Lactococcus taiwanensis. Resistance to 1024 μg mL-1 of tetracycline was observed in L. garvieae, S. arlettae, Enterobacter spp., B. faecalis. Tet(A) (67%) was the predominant resistance gene in tetHR followed by tet(L), tet(S), tet(K), and tet(M). At similar concentrations of exposure, tetracycline procured at the farm level (69.5% potency) exhibited lower inhibition against tetHR bacteria compared to pure tetracycline (99% potency). The tetHR bacteria showed higher cross-resistance to furazolidone (100%) followed by co-trimoxazole (47.5%) and enrofloxacin (11%). CONCLUSIONS: The maximum threshold of tetracycline resistance at 1024 μg mL-1 was observed in S. arlettae, Enterobacter spp., B. faecalis, and L. garvieae and tet(A) was the major determinant found in this study. | 2023 | 36958862 |
| 1322 | 5 | 0.9707 | Phenotypic and genotypic characterization of antimicrobial resistance in faecal enterococci from wild boars (Sus scrofa). The objective was to study the prevalence of antimicrobial resistance and the mechanisms implicated in faecal enterococci of wild boars in Portugal. One hundred and thirty-four enterococci (67 E. faecium, 54 E. hirae, 2 E. faecalis, 2 E. durans and 9 Enterococcus spp.) were recovered from 67 wild boars (two isolates/sample), and were further analysed. High percentages of resistance were detected for erythromycin, tetracycline, and ciprofloxacin (48.5%, 44.8%, and 17.9%, respectively), and lower values were observed for high-level-kanamycin, -streptomycin, chloramphenicol, and ampicillin resistance (9%, 6.7%, 4.5%, and 3.7%, respectively). No isolates showed vancomycin or high-level-gentamicin resistance. The erm(B), tet(M), aph(3')-IIIa, and ant(6)-I genes were demonstrated in all erythromycin-, tetracycline-, kanamycin-, and streptomycin-resistant isolates, respectively. Specific genes of Tn916/Tn1545 and Tn5397 transposons were detected in 78% and 47% of our tet(M)-positive enterococci, respectively. The tet(S) and tet(K) genes were detected in one isolate of E. faecium and E. hirae, respectively. Three E. faecium isolates showed quinupristin-dalfopristin resistance and the vat(E) gene was found in all of them showing the erm(B)-vat(E) linkage. Four E. faecium isolates showed ampicillin-resistance and all of them presented seven amino acid substitutions in PBP5 protein (461Q-->K, 470H-->Q, 485M-->A, 496N-->K, 499A-->T, 525E-->D, and 629E-->V), in relation with the reference one; a serine insertion at 466' position was found in three of the isolates. Faecal enterococci from wild boars harbour a variety of antimicrobial resistance mechanisms and could be a reservoir of antimicrobial resistance genes and resistant bacteria that could eventually be transmitted to other animals or even to humans. | 2007 | 17658226 |
| 1301 | 6 | 0.9705 | Phenotypic and Genotypic Assessment of Antibiotic Resistance of Staphylococcus aureus Bacteria Isolated from Retail Meat. BACKGROUND: Resistant Staphylococcus aureus (S. aureus) bacteria are determined to be one of the main causes of foodborne diseases. PURPOSE: This survey was done to assess the genotypic and phenotypic profiles of antibiotic resistance of S. aureus bacteria isolated from retail meat. METHODS: Four-hundred and eighty-five retail meat samples were collected and examined. S. aureus bacteria were identified using culture and biochemical tests. The phenotypic profile of antibiotic resistance was examined using the disk diffusion method. The genotypic pattern of antibiotic resistance was determined using the polymerase chain reaction. RESULTS: Forty-eight out of 485 (9.89%) raw retail meat samples were contaminated with S. aureus. Raw retail buffalo meat (16%) had the highest incidence of S. aureus, while raw camel meat (4%) had the lowest. S. aureus bacteria exhibited the uppermost incidence of resistance toward tetracycline (79.16%), penicillin (72.91%), gentamicin (60.41%), and doxycycline (41.666%). The incidence of resistance toward chloramphenicol (8.33%), levofloxacin (22.91%), rifampin (22.91%), and azithromycin (25%) was lower than other examined antibiotics. The most routinely detected antibiotic resistance genes were blaZ (58.33%), tetK (52.08%), aacA-D (33.33%), and ermA (27.08%). Cat1 (4.16%), rpoB (10.41%), msrA (12.50%), grlA (12.50%), linA (14.58%), and dfrA1 (16.66%) had the lower incidence rate. CONCLUSION: Raw meat of animals may be sources of resistant S. aureus which pose a hygienic threat about the consumption of raw meat. Nevertheless, further investigations are essential to understand supplementary epidemiological features of S. aureus in retail meat. | 2020 | 32440171 |
| 1223 | 7 | 0.9705 | Characterization of Escherichia coli virulence genes, pathotypes and antibiotic resistance properties in diarrheic calves in Iran. BACKGROUND: Calf diarrhea is a major economic concern in bovine industry all around the world. This study was carried out in order to investigate distribution of virulence genes, pathotypes, serogroups and antibiotic resistance properties of Escherichia coli isolated from diarrheic calves. RESULTS: Totally, 76.45% of 824 diarrheic fecal samples collected from Isfahan, Chaharmahal, Fars and Khuzestan provinces, Iran were positive for E. coli and all of them were also positive for cnf2, hlyA, cdtIII, f17c, lt, st, stx1, eae, ehly, stx2 and cnf1 virulence genes. Chaharmahal had the highest prevalence of STEC (84.61%), while Isfahan had the lowest (71.95%). E. coli serogroups had the highest frequency in 1-7 days old calves and winter season. Distribution of ETEC, EHEC, AEEC and NTEC pathotypes among E. coli isolates were 28.41%, 5.07%, 29.52% and 3.49%, respectively. Statistical analyses were significant for presence of bacteria between various seasons and ages. All isolates had the high resistance to penicillin (100%), streptomycin (98.25%) and tetracycline (98.09%) antibiotics. The most commonly detected resistance genes were aadA1, sul1, aac[3]-IV, CITM, and dfrA1. The most prevalent serogroup among STEC was O26. CONCLUSIONS: Our findings should raise awareness about antibiotic resistance in diarrheic calves in Iran. Clinicians should exercise caution when prescribing antibiotics. | 2014 | 25052999 |
| 1323 | 8 | 0.9705 | Detection of antibiotic resistant enterococci and Escherichia coli in free range Iberian Lynx (Lynx pardinus). Thirty fecal samples from wild specimens of Iberian lynx were collected and analyzed for Enterococcus spp. (27 isolates) and Escherichia coli (18 isolates) recovery. The 45 isolates obtained were tested for antimicrobial resistance, molecular mechanisms of resistance, and presence of virulence genes. Among the enterococci, Enterococcus faecium and Enterococcus hirae were the most prevalent species (11 isolates each), followed by Enterococcus faecalis (5 isolates). High percentages of resistance to tetracycline and erythromycin (33% and 30%, respectively) were detected among enterococcal isolates. The tet(M) and/or tet(L), erm(B), aac(6')-Ie-aph(2″)-Ia, ant(6)-Ia, or aph(3')-IIIa genes were detected among resistant enterococci. Virulence genes were detected in one E. faecalis isolate (cpd, cylB, and cylL) and one E. hirae isolate (cylL). High percentages of resistance were detected in E. coli isolates to tetracycline (33%), streptomycin (28%), nalidixic acid (28%), and sulfamethoxazole-trimethoprim (SXT, 22%). Additionally, the blaTEM, tet(A), aadA, cmlA, and different combinations of sul genes were detected among most ampicillin, tetracycline, streptomycin, chloramphenicol and SXT-resistant isolates, respectively. Two isolates contained a class 1 integron with the gene cassette arrays dfrA1 + aadA1 and dfrA12 + aadA2. The E. coli isolates were ascribed to phylo-groups A (n=5); B1 (n=4); B2 (n=6), and D (n=3), with the virulence gene fimA present in all E. coli isolates. This study found resistance genes in wild specimens of Iberian lynx. Thus, it is important to notice that multiresistant bacteria have reached species as rare and completely non-synanthropic as the Iberian lynx. Furthermore, the susceptibility of this endangered species to bacterial infection may be affected by the presence of these virulence and resistance genes. | 2013 | 23588135 |
| 1352 | 9 | 0.9705 | Bacterial Diversity and Antimicrobial Resistance of Microorganisms Isolated from Teat Cup Liners in Dairy Farms in Shandong Province, China. Global milk consumption exceeds 800 million tons a year and is still growing. Milk quality and its products are critical to human health. A teat cup makes direct contact with the cow's teats during milking and its cleanliness is very important for the quality of raw milk. In this study, the microorganism from post-milking teat cup liners were collected from six dairy farms in Shandong Province of China, the bacterial species were identified using microbial mass spectrometry, the minimum inhibitory concentrations of the isolated strains against ten antimicrobial agents were determined using the broth microdilution method, and the antimicrobial resistance genes were detected by PCR. The results indicated that the most frequently isolated bacteria in this study were Bacillus licheniformis (39/276, 14.13%), followed by Bacillus pumilus (20/276, 7.25%), Bacillus cereus (17/276, 6.16%), and Bacillus subtili (16/276, 5.80%). The isolates exhibited the highest average resistance to lincomycin (87.37%), followed by sulfadiazine (61.05%) and streptomycin (42.63%); the highest detection rate of resistance genes was Sul1 (55.43%), followed by ant(4') (51.09%), tet(M) (25.36%), bla(KPC) (3.62%) and qnrS (3.62%). These findings imply the necessity for enhanced measures in disinfecting cow udders and milking equipment, highlighting the persistently challenging issue of antimicrobial resistance in Shandong Province. | 2024 | 39123692 |
| 1261 | 10 | 0.9704 | Antibiotic Resistance Genes, Virulence Factors, and Biofilm Formation in Coagulase-Negative Staphylococcus spp. Isolates from European Hakes (Merluccius merluccius, L.) Caught in the Northeast Atlantic Ocean. The indiscriminate use of antibiotics has contributed to the dissemination of multiresistant bacteria, which represents a public health concern. The aim of this work was to characterize 27 coagulase-negative staphylococci (CoNS) isolated from eight wild Northeast Atlantic hakes (Merluccius merluccius, L.) and taxonomically identified as Staphylococcus epidermidis (n = 16), Staphylococcus saprophyticus (n = 4), Staphylococcus hominis (n = 3), Staphylococcus pasteuri (n = 2), Staphylococcus edaphicus (n = 1), and Staphylococcus capitis (n = 1). Biofilm formation was evaluated with a microtiter assay, antibiotic susceptibility testing was performed using the disk diffusion method, and antibiotic resistance and virulence determinants were detected by PCR. Our results showed that all staphylococci produced biofilms and that 92.6% of the isolates were resistant to at least one antibiotic, mainly penicillin (88.8%), fusidic acid (40.7%), and erythromycin (37%). The penicillin resistance gene (blaZ) was detected in 66.6% (18) of the isolates, of which 10 also carried resistance genes to macrolides and lincosamides (mphC, msr(A/B), lnuA, or vgaA), 4 to fusidic acid (fusB), and 3 to trimethoprim-sulfamethoxazole (dfrA). At least one virulence gene (scn, hla, SCCmecIII, and/or SCCmecV) was detected in 48% of the isolates. This study suggests that wild European hake destined for human consumption could act as a vector of CoNS carrying antibiotic resistance genes and/or virulence factors. | 2023 | 38133330 |
| 1264 | 11 | 0.9704 | Characterization of mannitol-fermenting methicillin-resistant staphylococci isolated from pigs in Nigeria. This study was conducted to determine the species distribution, antimicrobial resistance pheno- and genotypes and virulence traits of mannitol-positive methicillin-resistant staphylococci (MRS) isolated from pigs in Nsukka agricultural zone, Nigeria. Twenty mannitol-positive methicillin-resistant coagulase-negative staphylococcal (MRCoNS) strains harboring the mecA gene were detected among the 64 Staphylococcus isolates from 291 pigs. A total of 4 species were identified among the MRCoNS isolates, namely, Staphylococcus sciuri (10 strains), Staphylococcus lentus (6 strains), Staphylococcus cohnii (3 strains) and Staphylococcus haemolyticus (one strain). All MRCoNS isolates were multidrug-resistant. In addition to β-lactams, the strains were resistant to fusidic acid (85%), tetracycline (75%), streptomycin (65%), ciprofloxacin (65%), and trimethoprim/sulphamethoxazole (60%). In addition to the mecA and blaZ genes, other antimicrobial resistance genes detected were tet(K), tet(M), tet(L), erm(B), erm(C), aacA-aphD, aphA3, str, dfrK, dfrG, cat pC221, and cat pC223. Thirteen isolates were found to be ciprofloxacin-resistant, and all harbored a Ser84Leu mutation within the QRDR of the GyrA protein, with 3 isolates showing 2 extra substitutions, Ser98Ile and Arg100Lys (one strain) and Glu88Asp and Asp96Thr (2 strains). A phylogenetic tree of the QRDR nucleotide sequences in the gyrA gene revealed a high nucleotide diversity, with several major clusters not associated with the bacterial species. Our study highlights the possibility of transfer of mecA and other antimicrobial resistance genes from MRCoNS to pathogenic bacteria, which is a serious public health and veterinary concern. | 2015 | 26413075 |
| 1267 | 12 | 0.9704 | Detection and characterization of methicillin-resistant and susceptible coagulase-negative staphylococci in milk from cows with clinical mastitis in Tunisia. OBJECTIVES: This study investigated prevalence of methicillin-resistant (MR) and methicillin-susceptible (MS) coagulase-negative staphylococci (CNS) and the implicated mechanisms of resistance and virulence in milk of mastitis cows. In addition, the presence of SCCmec type was analyzed in MR Staphylococcus epidermidis (MRSE). RESULTS: Three hundred milk samples from cows with clinical mastitis were obtained from 30 dairy farms in different regions of Tunisia. Sixty-eight of the 300 tested samples contained CNS strains. Various CNS species were identified, with Staphylococcus xylosus being the most frequently found (40%) followed by Staphylococcus warneri (12%). The mecA gene was present in 14 of 20 MR-CNS isolates. All of them were lacking the mecC gene. The SCCmecIVa was identified in four MRSE isolates. Most of CNS isolates showed penicillin resistance (70.6%) and 58.3% of them carried the blaZ gene. MR-CNS isolates (n = 20) showed resistance to erythromycin, tetracycline and trimethoprim-sulfametoxazole harboring different resistance genes such us erm(B), erm(T), erm(C), mph(C) or msr(A), tet(K) and dfr(A). However, a lower percentage of resistance was observed among 48 MS-CNS isolates: erythromycin (8.3%), tetracycline (6.2%), streptomycin (6.2%), clindamycin (6.2%), and trimethoprim-sulfametoxazole (2%). The Inu(B) gene was detected in one Staphylococcus xylosus strain that showed clindamycin resistance. The virulence gene tsst-1 was observed in one MR-CNS strain. DISCUSSION: Coagulase-negative staphylococci containing a diversity of antimicrobial resistance genes are frequently detected in milk of mastitis cows. This fact emphasizes the importance of identifying CNS when an intramammary infection is present because of the potential risk of lateral transfer of resistant genes among staphylococcal species and other pathogenic bacteria. | 2018 | 30077662 |
| 5387 | 13 | 0.9703 | Assessment of antibiotic susceptibility within lactic acid bacteria strains isolated from wine. Susceptibility to 12 antibiotics was tested in 75 unrelated lactic acid bacteria strains of wine origin of the following species: 38 Lactobacillus plantarum, 3 Lactobacillus hilgardii, 2 Lactobacillus paracasei, 1 Lactobacillus sp, 21 Oenococcus oeni, 4 Pediococcus pentosaceus, 2 Pediococcus parvulus, 1 Pediococcus acidilactici, and 3 Leuconostoc mesenteroides. The Minimal Inhibitory Concentrations of the different antibiotics that inhibited 50% of the strains of the Lactobacillus, Leuconostoc and Pediococcus genera were, respectively, the following ones: penicillin (2, < or =0.5, and < or =0.5 microg/ml), erythromycin (< or =0.5 microg/ml), chloramphenicol (4 microg/ml), ciprofloxacin (64, 8, and 128 microg/ml), vancomycin (> or =128 microg/ml), tetracycline (8, 2, and 8 microg/ml), streptomycin (256, 32, and 512 microg/ml), gentamicin (64, 4, and 128 microg/ml), kanamycin (256, 64, and 512 microg/ml), sulfamethoxazole (> or =1024 microg/ml), and trimethoprim (16 microg/ml). All 21 O. oeni showed susceptibility to erythromycin, tetracycline, rifampicin and chloramphenicol, and exhibited resistance to aminoglycosides, vancomycin, sulfamethoxazole and trimethoprim, that could represent intrinsic resistance. Differences were observed among the O. oeni strains with respect to penicillin or ciprofloxacin susceptibility. Antibiotic resistance genes were studied by PCR and sequencing, and the following genes were detected: erm(B) (one P. acidilactici), tet(M) (one L. plantarum), tet(L) (one P. parvulus), aac(6')-aph(2") (four L. plantarum, one P. parvulus, one P. pentosaceus and two O. oeni), ant(6) (one L. plantarum, and two P. parvulus), and aph(3')-IIIa (one L. plantarum and one O. oeni). This is the first time, to our knowledge, that ant(6), aph(3')-IIIa and tet(L) genes are found in Lactobacillus and Pediococcus strains and antimicrobial resistance genes are reported in O. oeni strains. | 2006 | 16876896 |
| 1302 | 14 | 0.9703 | A survey of prevalence and phenotypic and genotypic assessment of antibiotic resistance in Staphylococcus aureus bacteria isolated from ready-to-eat food samples collected from Tehran Province, Iran. BACKGROUND: Resistant Staphylococcus aureus (S. aureus) bacteria are considered among the major causes of foodborne diseases. This survey aims to assess genotypic and phenotypic profiles of antibiotic resistance in S. aureus bacteria isolated from ready-to-eat food samples. METHODS: According to the previously reported prevalence of S. aureus in ready-to-eat food samples, a total of 415 ready-to-eat food samples were collected from Tehran province, Iran. S. aureus bacteria were identified using culture and biochemical tests. Besides, the phenotypic antibiotic resistance profile was determined by disk diffusion. In addition, the genotypic pattern of antibiotic resistance was determined using the PCR. RESULTS: A total of 64 out of 415 (15.42%) ready-to-eat food samples were contaminated with S. aureus. Grilled mushrooms and salad olivieh harbored the highest contamination rate of (30%), while salami samples harbored the lowest contamination rate of 3.33%. In addition, S. aureus bacteria harbored the highest prevalence of resistance to penicillin (85.93%), tetracycline (85.93%), gentamicin (73.43%), erythromycin (53.12%), trimethoprim-sulfamethoxazole (51.56%), and ciprofloxacin (50%). However, all isolates were resistant to at least four antibiotic agents. Accordingly, the prevalence of tetK (70.31%), blaZ (64.06%), aacA-D (57.81%), gyrA (50%), and ermA (39.06%) was higher than that of other detected antibiotic resistance genes. Besides, AacA-D + blaZ (48.43%), tetK + blaZ (46.87%), aacA-D + tetK (39.06%), aacA-D + gyrA (20.31%), and ermA + blaZ (20.31%) were the most frequently identified combined genotypic patterns of antibiotic resistance. CONCLUSION: Ready-to-eat food samples may be sources of resistant S. aureus, which pose a hygienic threat in case of their consumption. However, further investigations are required to identify additional epidemiological features of S. aureus in ready-to-eat foods. | 2021 | 34635183 |
| 1283 | 15 | 0.9703 | Antimicrobial Resistance Profiles of Staphylococcus Isolated from Cows with Subclinical Mastitis: Do Strains from the Environment and from Humans Contribute to the Dissemination of Resistance among Bacteria on Dairy Farms in Colombia? Staphylococcus is a very prevalent etiologic agent of bovine mastitis, and antibiotic resistance contributes to the successful colonization and dissemination of these bacteria in different environments and hosts on dairy farms. This study aimed to identify the antimicrobial resistance (AMR) genotypes and phenotypes of Staphylococcus spp. isolates from different sources on dairy farms and their relationship with the use of antibiotics. An antimicrobial susceptibility test was performed on 349 Staphylococcus strains (S. aureus, n = 152; non-aureus staphylococci (NAS), n = 197) isolated from quarter milk samples (QMSs) from cows with subclinical mastitis (176), the teats of cows (116), the milking parlor environment (32), and the nasal cavities of milk workers (25). Resistance and multidrug resistance percentages found for S. aureus and NAS were (S. aureus = 63.2%, NAS = 55.8%) and (S. aureus = 4.6%, NAS = 11.7%), respectively. S. aureus and NAS isolates showed resistance mainly to penicillin (10 IU) (54.1% and 32.4%) and ampicillin (10 mg) (50.3% and 27.0%) drugs. The prevalence of AMR Staphylococcus was higher in environmental samples (81.3%) compared to other sources (52.6-76.0%). In S. aureus isolates, the identification of the blaZ (83.9%), aacAaphD (48.6%), ermC (23.5%), tetK (12.9%), and mecA (12.1%) genes did not entirely agree with the AMR phenotype. We conclude that the use of β-lactam antibiotics influences the expression of AMR in Staphylococcus circulating on dairy farms and that S. aureus isolates from the environment and humans may be reservoirs of AMR for other bacteria on dairy farms. | 2023 | 37998777 |
| 1265 | 16 | 0.9701 | Coagulase-negative staphylococci (CoNS) isolated from ready-to-eat food of animal origin--phenotypic and genotypic antibiotic resistance. The aim of this work was to study the pheno- and genotypical antimicrobial resistance profile of coagulase negative staphylococci (CoNS) isolated from 146 ready-to-eat food of animal origin (cheeses, cured meats, sausages, smoked fishes). 58 strains were isolated, they were classified as Staphylococcus xylosus (n = 29), Staphylococcus epidermidis (n = 16); Staphylococcus lentus (n = 7); Staphylococcus saprophyticus (n = 4); Staphylococcus hyicus (n = 1) and Staphylococcus simulans (n = 1) by phenotypic and genotypic methods. Isolates were tested for resistance to erythromycin, clindamycin, gentamicin, cefoxitin, norfloxacin, ciprofloxacin, tetracycline, tigecycline, rifampicin, nitrofurantoin, linezolid, trimetoprim, sulphamethoxazole/trimethoprim, chloramphenicol, quinupristin/dalfopristin by the disk diffusion method. PCR was used for the detection of antibiotic resistance genes encoding: methicillin resistance--mecA; macrolide resistance--erm(A), erm(B), erm(C), mrs(A/B); efflux proteins tet(K) and tet(L) and ribosomal protection proteins tet(M). For all the tet(M)-positive isolates the presence of conjugative transposons of the Tn916-Tn1545 family was determined. Most of the isolates were resistant to cefoxitin (41.3%) followed by clindamycin (36.2%), tigecycline (24.1%), rifampicin (17.2%) and erythromycin (13.8%). 32.2% staphylococcal isolates were multidrug resistant (MDR). All methicillin resistant staphylococci harboured mecA gene. Isolates, phenotypic resistant to tetracycline, harboured at least one tetracycline resistance determinant on which tet(M) was most frequent. All of the isolates positive for tet(M) genes were positive for the Tn916-Tn1545 -like integrase family gene. In the erythromycin-resistant isolates, the macrolide resistance genes erm(C) or msr(A/B) were present. Although coagulase-negative staphylococci are not classical food poisoning bacteria, its presence in food could be of public health significance due to the possible spread of antibiotic resistance. | 2015 | 25475289 |
| 1300 | 17 | 0.9700 | Genotypic and Phenotypic-Based Assessment of Antibiotic Resistance and Profile of Staphylococcal Cassette Chromosome mec in the Methicillin-Resistant Staphylococcus aureus Recovered from Raw Milk. BACKGROUND: Multidrug resistant methicillin-resistant Staphylococcus aureus (MRSA) bacteria are determined to be one of the chief causes of foodborne diseases around the world. PURPOSE: This research was done to assess the genotypic and phenotypic profiles of antibiotic resistance and distribution of Staphylococcus cassette chromosome mec (SCCmec) types amongst the MRSA bacteria recovered from raw milk. METHODS: Five-hundred and ninety raw milk samples were collected and examined. MRSA bacteria were recognized using susceptibility evaluation toward oxacillin and cefoxitin disks. Profile of antibiotic resistance genes and SCCmec types were determined using the PCR. Antibiotic resistance pattern of isolates was examined using the disk diffusion. RESULTS: Thirty-nine out of 590 raw milk samples (6.61%) were positive for S. aureus. Twenty-eight out of 39 (71.79%) bacteria were defined as MRSA bacteria. Raw buffalo (80%) milk samples had the maximum incidence of MRSA, while raw camel (33.33%) had the minimum. MRSA bacteria harbored the maximum incidence of resistance toward penicillin (100%), tetracycline (100%), erythromycin (82.14%), gentamicin (78.57%) and trimethoprim-sulfamethoxazole (78.57%). Incidence of resistance toward more than eight classes of antibiotic agents was 28.57%. The most frequently distinguished antibiotic resistance markers were blaZ (100%), tetK (85.71%), dfrA1 (71.42%), aacA-D (67.85%), ermA (50%) and gyrA (42.85%). SCCmec IVa (29.62%), V (25%), III (14.81%) and IVb (11.11%) were the most frequently distinguished types. CONCLUSION: Raw milk of dairy animals maybe sources of multidrug resistant MRSA which pose a hygienic threat concerning the consumption of raw milk in Iran. Nevertheless, further investigations are necessary to understand supplementary epidemiological features of MRSA in raw milk. | 2020 | 32099419 |
| 1254 | 18 | 0.9700 | Genetic diversity and antimicrobial resistance of Staphylococcus aureus from recurrent tonsillitis in children. The aim of this study was to analyze the prevalence of Staphylococcus aureus in the tonsils of children subjected tonsillectomy due to recurrent tonsilitis and to determine the spa types of the pathogens, carriage of virulence genes and antimicrobial resistance profiles. The study included 73 tonsillectomized children. Bacteria, including S. aureus were isolated from tonsillar surface prior to tonsillectomy, recovered from tonsillar core at the time of the surgery, and from posterior pharynx 2-4 weeks after the procedure. Staphylococcus aureus isolates were compared by spa typing, tested for antimicrobial susceptibility and for the presence of superantigenic toxin genes (sea-seu, eta, etb, tst, lukS/lukF-PV) by multiplex polymerase chain reaction. Seventy-three patients (mean 7.1 ± 4.1 years, 61.6% male) were assessed. The most commonly isolated bacteria were S. aureus. The largest proportion of staphylococcal isolates originated from tonsillar core (63%), followed by tonsillar surface (45.1%) and posterior pharynx in tonsillectomized children (18.2%, p = 0.007). Five (6.3%) isolates were identified as MRSA (mecA-positive). Up to 67.5% of the isolates synthesized penicillinases (blaZ-positive isolates), and 8.8% displayed MLS(B) resistance. The superantigenic toxin genes were detected in more than half of examined isolates (56.3%). spa types t091, t084, and t002, and clonal complexes (CCs) CC7, CC45, and CC30 turned out to be most common. Staphylococcus aureus associated with RT in children showed pathogenicity potential and considerable genetic diversity, and no clones were found to be specific for this condition although further studies are needed. | 2020 | 31692060 |
| 1324 | 19 | 0.9700 | Molecular characterization of antimicrobial resistance in enterococci and Escherichia coli isolates from European wild rabbit (Oryctolagus cuniculus). A total of 44 Escherichia coli and 64 enterococci recovered from 77 intestinal samples of wild European rabbits in Portugal were analyzed for resistance to antimicrobial agents. Resistance in E. coli isolates was observed for ampicillin, tetracycline, sulfamethoxazole/trimethoprim, streptomycin, gentamicin, tobramycin, nalidixic acid, ciprofloxacin and chloramphenicol. None of the E. coli isolates produced extended-spectrum beta-lactamases (ESBLs). The bla(TEM), aadA, aac(3)-II, tet(A) and/or tet(B), and the catA genes were demonstrated in all ampicillin, streptomycin, gentamicin, tetracycline, and chloramphenicol-resistant isolates respectively, and the sul1 and/or sul2 and/or sul3 genes in 4 of 5 sulfamethoxazole/trimethoprim resistant isolates. Of the enterococcal isolates, Enterococcus faecalis was the most prevalent detected species (39 isolates), followed by E. faecium (21 isolates) and E. hirae (4 isolates). More than one-fourth (29.7%) of the isolates were resistant to tetracycline; 20.3% were resistant to erythromycin, 14.1% were resistant to ciprofloxacin and 10.9% were resistant to high-level-kanamycin. Lower level of resistance (<10%) was detected for ampicillin, quinupristin/dalfopristin and high-level-gentamicin, -streptomycin. No vancomycin-resistance was detected in the enterococci isolates. Resistance genes detected included aac(6')-aph(2''), ant(6)-Ia, tet(M) and/or tet(L) in all gentamicin, streptomycin and tetracycline-resistant isolates respectively. The aph(3')-IIIa gene was detected in 6 of 7 kanamycin-resistant isolates, the erm(B) gene in 11 of 13 erythromycin-resistant isolates and the vat(D) gene in the quinupristin/dalfopristin-resistant E. faecium isolate. This survey showed that faecal bacteria such as E. coli and enterococci of wild rabbits could be a reservoir of antimicrobial resistance genes. | 2010 | 20624632 |