Detection of a mecC-positive Staphylococcus saprophyticus from bovine mastitis in Argentina. - Related Documents




#
Rank
Similarity
Title + Abs.
Year
PMID
012345
239301.0000Detection of a mecC-positive Staphylococcus saprophyticus from bovine mastitis in Argentina. INTRODUCTION: Bovine mastitis causes important economic losses in the dairy industry. Coagulase-negative staphylococci (CNS) are a group of bacteria commonly isolated from bovine mastitis and can display resistance to a wide range of antimicrobial agents. OBJECTIVES: The objective of this study was to determine staphylococcal resistance towards β-lactam, macrolide and lincosamide antimicrobials in quarters previously treated with third-generation cephalosporin and after lincosamide intramammary therapy. METHODS: Sick quarters of eighteen cows from Villaguay, Entre Ríos (Argentina) with clinical mastitis were studied. All staphylococcal isolates were tested by disk diffusion for their antimicrobial susceptibilities. Cefoxitin resistance was investigated by PCR and sequencing for both the mecA and mecC genes. RESULTS: Resistances to penicillin, oxacillin and cefoxitin were observed, whereas no resistance to macrolide and lincosamide was detected. A cefoxitin-resistant Staphylococcus saprophyticus was found to be mecA-negative but mecC-positive. CONCLUSIONS: This study reports for the first time the mecC gene from a CNS in bovine mastitis in South America. Because CNS may act as reservoirs of antimicrobial resistance genes, they can be seen as a potential public health threat with respect to antimicrobial resistance and the development of multiple resistance. Also, the emergence of methicillin-resistant phenotypes will limit therapeutic options.201728732791
266010.9998Antimicrobial resistance and virulence characteristics in 3 collections of staphylococci from bovine milk samples. Mastitis is a prevalent disease in dairy cattle, and staphylococci are among the most common causative pathogens. Staphylococci can express resistance to a range of antimicrobials, of which methicillin resistance is of particular public health concern. Additionally, Staphylococcus aureus carries a variety of virulence factors, although less is understood about the virulence of non-aureus staphylococci (NAS). The aim of our study was to identify and characterize 3 collections of staphylococcal isolates from bovine milk samples regarding antimicrobial resistance, with emphasis on methicillin resistance, and their carriage of virulence genes typically displayed by Staph. aureus. A total of 272 staphylococcal isolates collected in Norway and Belgium in 2016 were included, distributed as follows: group 1, Norway, 100 isolates; group 2, Flanders, Belgium, 64 isolates; group 3, Wallonia, Belgium, 108 isolates. Species identification was performed by use of MALDI-TOF mass spectrometry. Phenotypic resistance was determined via disk diffusion, and PCR was used for detection of methicillin resistance genes, mecA and mecC, and virulence genes. Antimicrobial resistance was common in Staphylococcus epidermidis and Staphylococcus haemolyticus from all different groups, with resistance to trimethoprim-sulfonamide frequently occurring in Staph. epidermidis and Staph. haemolyticus as well as in Staph. aureus. Resistance to penicillin was most frequently observed in group 1. Ten Belgian isolates (1 from group 2, 9 from group 3) carried the methicillin resistance determinant mecA: 5 Staph. aureus from 2 different farms and 5 NAS from 3 different farms. Almost all Staph. aureus isolates were positive for at least 3 of the screened virulence genes, whereas, in total, only 8 NAS isolates harbored any of the same genes. Our study contributes to the continuous need for knowledge regarding staphylococci from food-producing animals as a basis for better understanding of occurrence of resistance and virulence traits in these bacteria.202133934873
240620.9998Prevalence of antibiotic resistance genes in staphylococci isolated from ready-to-eat meat products. Prevalence of mecA, blaZ, tetO/K/M, ermA/B/C, aph, and vanA/B/C/D genes conferring resistance to oxacillin, penicillin, tetracycline, erythromycin, gentamicin, and vancomycin was investigated in 65 staphylococcal isolates belonging to twelve species obtained from ready-to-eat porcine, bovine, and chicken products. All coagulase negative staphylococci (CNS) and S. aureus isolates harbored at least one antibiotic resistance gene. None of the S. aureus possessed more than three genes, while 25% of the CNS isolates harbored at least four genes encoding resistance to clinically used antibiotics. In 15 CNS isolates the mecA gene was detected, while all S. aureus isolates were mecA-negative. We demonstrate that in ready-to-eat food the frequency of CNS harboring multiple antibiotic resistance genes is higher than that of multiple resistant S. aureus, meaning that food can be considered a reservoir of bacteria containing genes potentially contributing to the evolution of antibiotic resistance in staphylococci.201222844699
239230.9998Characterization of the resistome and predominant genetic lineages of Gram-positive bacteria causing keratitis. Bacterial keratitis is a vision-threatening infection mainly caused by Gram-positive bacteria (GPB). Antimicrobial therapy is commonly empirical using broad-spectrum agents with efficacy increasingly compromised by the emergence of antimicrobial resistance. We used a combination of phenotypic tests and genome sequencing to identify the predominant lineages of GPB causing keratitis and to characterize their antimicrobial resistance patterns. A total of 161 isolates, including Staphylococcus aureus (n = 86), coagulase-negative staphylococci (CoNS; n = 34), Streptococcus spp. (n = 34), and Enterococcus faecalis (n = 7), were included. The population of S. aureus isolates consisted mainly of clonal complex 5 (CC5) (30.2%). Similarly, the population of Staphylococcus epidermidis was homogenous with most of them belonging to CC2 (78.3%). Conversely, the genetic population of Streptococcus pneumoniae was highly diverse. Resistance to first-line antibiotics was common among staphylococci, especially among CC5 S. aureus. Methicillin-resistant S. aureus was commonly resistant to fluoroquinolones and azithromycin (78.6%) and tobramycin (57%). One-third of the CoNS were resistant to fluoroquinolones and 53% to azithromycin. Macrolide resistance was commonly caused by erm genes in S. aureus, mphC and msrA in CoNS, and mefA and msr(D) in streptococci. Aminoglycoside resistance in staphylococci was mainly associated with genes commonly found in mobile genetic elements and that encode for nucleotidyltransferases like ant(4')-Ib and ant(9)-Ia. Fluroquinolone-resistant staphylococci carried from 1 to 4 quinolone resistance-determining region mutations, mainly in the gyrA and parC genes. We found that GPB causing keratitis are associated with strains commonly resistant to first-line topical therapies, especially staphylococcal isolates that are frequently multidrug-resistant and associated with major hospital-adapted epidemic lineages.202438289077
240040.9998Antimicrobial 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.200718251398
266150.9998Antimicrobial resistance in Staphylococcus pseudintermedius on the environmental surfaces of a recently constructed veterinary hospital in Southern Thailand. BACKGROUND AND AIM: Staphylococcus pseudintermedius is a zoonotic bacterium commonly found in animals, especially dogs. These bacteria can survive on environmental surfaces for several months. The infection of S. pseudintermedius from the environment is possible, but properly cleaning surface objects can prevent it. This study aimed to investigate the prevalence of methicillin-resistant S. pseudintermedius (MRSP) in the environment of a recently constructed veterinary hospital in Southern Thailand, where we hypothesized that the prevalence of MRSP might be very low. MATERIALS AND METHODS: At three different time points, 150 samples were collected from different environmental surfaces and wastewater across the veterinary hospital. The collection was done after the hospital's cleaning. Bacteria were purified in the culture before being identified as species by biochemical tests and polymerase chain reaction (PCR). Next, the antimicrobial-resistant profile was performed using an automated system (Vitek 2). Finally, the antimicrobial resistance genes were identified using PCR. RESULTS: Fifteen colonies of S. pseudintermedius were isolated from the surfaces of eight floors, four tables, two chairs, and one rebreathing tube. Fourteen colonies (93.3%) were multidrug-resistant (MDR) and carried the blaZ gene (93.3%). The majority of colonies were resistant to benzylpenicillin (93.3%), cefovecin (93.3%), ceftiofur (93.3%), kanamycin (93.3%), and neomycin (93.3%). Notably, only four colonies (26.7%) were methicillin-susceptible S. pseudintermedius, whereas 11 colonies (73.3%) were MRSP and carried both the mecA and blaZ genes. Five MRSP (45.5%) were resistant to at least 14 antimicrobial drugs, represented as extensively drug-resistant (XDR) bacteria. Ten of eleven MRSP (90.9%) were Staphylococcal chromosomal mec type V, while another displayed untypeable. Despite the routine and extensive cleaning with detergent and disinfectant, MRSP isolates were still detectable. CONCLUSION: Many isolates of MRSP were found in this veterinary hospital. Almost all of them were MDR, and nearly half were XDR, posing a threat to animals and humans. In addition, the current hospital cleaning procedure proved ineffective. Future research should be conducted to determine the bacterial biofilm properties and bacterial sensitivity to certain detergents and disinfectants.202235698521
553460.9998Antibiotic resistance in faecal microbiota of Greek healthy infants. Increasing use of antibiotics for the treatment of infectious diseases and also for non-therapeutic reasons (agriculture, animal husbandry and aquaculture) has led to the increasing incidence of antibiotic resistance and the ineffectiveness of antimicrobial treatment. Commensal intestinal bacteria are very often exposed to the selective pressure of antimicrobial agents and may constitute a reservoir of antibiotic resistance determinants that can be transferred to pathogens. The present study aimed to investigate the antibiotic susceptibility profile and the presence of selected resistance genes in cocci isolated from the faecal microbiota of 35 healthy, full-term infants at 4, 30 and 90 days after delivery. A total of 148 gram-positive, catalase-negative cocci were isolated and tested for susceptibility to 12 different antibiotics by disk-diffusion technique. Multiplex PCR analysis was performed for the identification of Enterococcus spp. isolates and the simultaneous detection of vancomycin-resistance genes. PCR-based methodology was used also for identification of tetracycline and erythromycin resistance determinants. Identification results indicated E. faecalis as the predominant species (81 strains), followed by E. faecium, E. casseliflavus/E. flavescens and E. gallinarum. High prevalence of resistance to tetracycline (39.9%), erythromycin (35.1%), vancomycin (19.6%) and to nucleic acid synthesis inhibitors was detected. PCR data revealed 24 out of 52 erythromycin-resistant isolates carrying the ermB gene and 32 out of 59 tetracycline-resistant strains carrying tet genes, with tet(L) determinant being the most frequently detected. Only intrinsic vancomycin resistance (vanC1 and vanC2/C3) was reported among tested isolates. In conclusion, erythromycin and tetracycline acquired resistant traits are widespread among faecal cocci isolates from Greek, healthy infants under no apparent antimicrobial selective pressure.201021831766
553870.9998Phenotypic and genotypic antimicrobial susceptibility pattern of Streptococcus spp. isolated from cases of clinical mastitis in dairy cattle in Poland. Mastitis of dairy cattle is one of the most frequently diagnosed diseases worldwide. The main etiological agents of mastitis are bacteria of the genus Streptococcus spp., in which several antibiotic resistance mechanisms have been identified. However, detailed studies addressing this problem have not been conducted in northeastern Poland. Therefore, the aim of our study was to analyze, on phenotypic and genotypic levels, the antibiotic resistance pattern of Streptococcus spp. isolated from clinical cases of mastitis from dairy cattle in this region of Poland. The research was conducted using 135 strains of Streptococcus (Streptococcus uberis, n = 53; Streptococcus dysgalactiae, n = 41; Streptococcus agalactiae, n = 27; other streptococci, n = 14). The investigation of the antimicrobial susceptibility to 8 active substances applied in therapy in the analyzed region, as well as a selected bacteriocin (nisin), was performed using the minimum inhibitory concentration method. The presence of selected resistance genes (n = 14) was determined via PCR. We also investigated the correlation between the presence of resistance genes and the antimicrobial susceptibility of the examined strains in vitro. The highest observed resistance of Streptococcus spp. was toward gentamicin, kanamycin, and tetracycline, whereas the highest susceptibility occurred toward penicillin, enrofloxacin, and marbofloxacin. Additionally, the tested bacteriocin showed high efficacy. The presence of 13 analyzed resistance genes was observed in the examined strains [gene mef(A) was not detected]. In most strains, at least one resistance gene, mainly responsible for resistance to tetracyclines [tet(M), tet(K), tet(L)], was observed. However, a relationship between the presence of a given resistance gene and antimicrobial susceptibility on the phenotypic level was not always observed.201728601447
550580.9998Concordance between Antimicrobial Resistance Phenotype and Genotype of Staphylococcus pseudintermedius from Healthy Dogs. Staphylococcus pseudintermedius, a common commensal canine bacterium, is the main cause of skin infections in dogs and is a potential zoonotic pathogen. The emergence of methicillin-resistant S. pseudintermedius (MRSP) has compromised the treatment of infections caused by these bacteria. In this study, we compared the phenotypic results obtained by minimum inhibitory concentration (MICs) for 67 S. pseudintermedius isolates from the skin of nine healthy dogs versus the genotypic data obtained with Nanopore sequencing. A total of 17 antibiotic resistance genes (ARGs) were detected among the isolates. A good correlation between phenotype and genotype was observed for some antimicrobial classes, such as ciprofloxacin (fluoroquinolone), macrolides, or tetracycline. However, for oxacillin (beta-lactam) or aminoglycosides the correlation was low. Two antibiotic resistance genes were located on plasmids integrated in the chromosome, and a third one was in a circular plasmid. To our knowledge, this is the first study assessing the correlation between phenotype and genotype regarding antimicrobial resistance of S. pseudintermedius from healthy dogs using Nanopore sequencing technology.202236421269
559990.9998Antimicrobial susceptibility profiles of Staphylococcus spp. contaminating raw goat milk. BACKGROUND AND AIM: Antimicrobial resistance poses a major threat to global public health. Foodstuff of animal origin can serve as potential vehicles for the dissemination of antimicrobial-resistant bacteria and resistance genes to consumers. In view of the lack of knowledge about antimicrobial resistance in bacteria associated with goat milk, the aim of this study was to report species-level identification and antimicrobial susceptibility profiles of a large collection of Staphylococcus spp. isolates recovered from raw goat milk in Brazil. MATERIALS AND METHODS: A total of 434 Staphylococcus spp. isolates originated from 510 goat milk samples in Northeast Brazil were investigated. The isolates were obtained by conventional microbiological methods. Species identification and antimicrobial susceptibility testing were performed by means of a semi-automated system using a panel for biochemical tests and broth microdilution method for 19 antimicrobial drugs. RESULTS: Although Staphylococcus aureus (22.6%) accounted for the majority of the isolates, a total of 13 different non-aureus staphylococci spp. were identified. High resistance rates against erythromycin (40.8%), and the beta-lactams ampicillin (45.9%) and penicillin (42.9%) were observed among S. aureus isolates. The most significant findings were related to the resistance against quinupristin-dalfopristin, a drug of last resort used in human medicine to treat infections caused by vancomycin-resistant S. aureus and enterococci. CONCLUSION: The high diversity of Staphylococcus spp. showing phenotypic resistance against different antimicrobial drugs encourages further investigations on the real impact of these bacteria as reservoirs of antimicrobial resistance genes to consumers. Furthermore, the potential impact of technological processes, such as pasteurization, fermentation, and maturation, on the maintenance and dissemination of antimicrobial resistance among the microbial populations in milk and dairy products must also be investigated.202134220106
2402100.9998Antimicrobial Resistance and Virulence Genes in Staphylococci Isolated from Aviary Capercaillies and Free-living Birds in South-eastern Poland. INTRODUCTION: The current study characterises Staphylococcus bacteria recovered from dead free-living birds and captive capercaillies kept in south-eastern Poland. The results provide novel information about the antimicrobial resistance phenotype/genotype and the virulence profile of these bacteria. MATERIAL AND METHODS: Samples of internal organs were taken from dead birds. Staphylococcus strains were identified by matrix-assisted laser desorption/ionisation-time-of-flight mass spectrometry. Susceptibility to 13 antibiotics was tested using a standard disc diffusion method on Mueller-Hinton agar. All isolates were screened for the presence of antibiotic resistance genes and staphylococcal enterotoxins (A to E), toxic shock syndrome toxin 1, exfoliative toxins A and B and Panton-Valentine leukocidin. RESULTS: A total of 129 bacterial strains belonging to 19 species of the Staphylococcus genus were isolated. A relatively high percentage of them resisted fluoroquinolones, tetracyclines, macrolides and β-lactams to a significant degree and harboured the tetK, tetM, ermC, mphC and mecA genes. Strains of the coagulase-negative S. sciuri, S. xylosus and S. cohnii were isolated with genes encoding enterotoxin A and toxic shock syndrome toxin. CONCLUSION: Both coagulase-positive and coagulase-negative staphylococci isolated from aviary capercaillies and free-living birds have significant pathogenic potential, and greater attention must be paid to the coagulase-negative species, which are still often considered mere contaminants. Virulence factors associated with resistance to antimicrobials, this being multiple in some strains, seem most important because they can be easily transferred between animals, especially those living in a given area.202236349137
2407110.9998Antibiotic resistance genes and identification of staphylococci collected from the production chain of swine meat commodities. Staphylococci harbouring antibiotic resistance (AR) genes may represent a hazard for human health and, as other resistant food-related bacteria, they contribute to the spread of AR. In this study, we isolated resistant staphylococci from an entire swine production chain and investigated the occurrence of 11 genes [aac(6')Ie-aph(2'')Ia, blaZ, mecA, vanA, vanB, ermA, ermB, ermC, tet(M), tet(O) and tet(K)] encoding resistance to some antibiotics largely used in clinical practice. The 66 resistant staphylococcal isolates were identified as Staphylococcus epidermidis (27 isolates), Staphylococcus aureus (12), Staphylococcus xylosus (12), Staphylococcus simulans (5), Staphylococcus pasteuri (4), Staphylococcus carnosus (3), Staphylococcus lentus (2) and Staphylococcus sciuri (1). Specific-PCR detection of AR genes showed the prevalence of the tet(K) gene in most of the isolates (89.4%), followed by tet(M) and ermC (about 75%); mecA was detected in more than half of S. aureus and S. epidermidis isolates. The genes vanA and vanB were not retrieved. It was found that a high proportion of coagulase-positive and -negative isolates are multidrug-resistant and some of them carry up to six AR genes. Our findings show that the swine production chain is a source of antibiotic-resistant staphylococci suggesting the importance of resistance surveillance in the food production environment.200817993395
2662120.9998Nasal Carriage of Methicillin-Resistant Staphylococcus Sciuri Group by Residents of an Urban Informal Settlement in Kenya. BACKGROUND: The Staphylococcus sciuri group constitutes animal-associated bacteria but can comprise up to 4% of coagulase-negative staphylococci isolated from human clinical samples. They are reservoirs of resistance genes that are transferable to Staphylococcus aureus but their distribution in communities in sub-Saharan Africa is unknown despite the clinical importance of methicillin-resistant S. aureus. OBJECTIVES: We characterised methicillin-resistant S. sciuri group isolates from nasal swabs of presumably healthy people living in an informal settlement in Nairobi to identify their resistance patterns, and carriage of two methicillin resistance genes. METHOD: Presumptive methicillin-resistant S. sciuri group were isolated from HardyCHROM™ methicillin-resistant S. aureus media. Isolate identification and antibiotic susceptibility testing were done using the VITEK(®)2 Compact. DNA was extracted using the ISOLATE II genomic kit and polymerase chain reaction used to detect mecA and mecC genes. Results: Of 37 presumptive isolates, 43% (16/37) were methicillin-resistant including - S. sciuri (50%; 8/16), S. lentus (31%; 5/16) and S. vitulinus (19%; 3/16). All isolates were susceptible to ciprofloxacin, gentamycin, levofloxacin, moxifloxacin, nitrofurantoin and tigecycline. Resistance was observed to clindamycin (63%), tetracycline (56%), erythromycin (56%), sulfamethoxazole/trimethoprim (25%), daptomycin (19%), rifampicin (13%), doxycycline, linezolid, and vancomycin (each 6%). Most isolates (88%; 14/16) were resistant to at least 2 antibiotic combinations, including methicillin. The mecA and mecC genes were identified in 75% and 50% of isolates, respectively. CONCLUSION: Colonizing S. sciuri group bacteria can carry resistance to methicillin and other therapeutic antibiotics. This highlights their potential to facilitate antimicrobial resistance transmission in community and hospital settings. Surveillance for emerging multidrug resistant strains should be considered in high transmission settings where human-animal interactions are prevalent. Our study scope precluded identifying other molecular determinants for all the observed resistance phenotypes. Larger studies that address the prevalence and risk factors for colonization with S. sciuri group and adopt a one health approach can complement the surveillance efforts.202337529492
5600130.9998The Characterization and Beta-Lactam Resistance of Staphylococcal Community Recovered from Raw Bovine Milk. Staphylococci is an opportunistic bacterial population that is permanent in the normal flora of milk and poses a serious threat to animal and human health with some virulence factors and antibiotic-resistance genes. This study was aimed at identifying staphylococcal species isolated from raw milk and to determine hemolysis, biofilm, coagulase activities, and beta-lactam resistance. The raw milk samples were collected from the Düzce (Türkiye) region, and the study data represent a first for this region. The characterization of the bacteria was performed with MALDI-TOF MS and 16S rRNA sequence analysis. The presence of coa, icaB, blaZ, and mecA was investigated with PCR. A nitrocefin chromogenic assay was used for beta-lactamase screening. In this context, 84 staphylococci were isolated from 10 different species, and the dominant species was determined as S. aureus (32.14%). Although 32.14% of all staphylococci were positive for beta hemolysis, the icaB gene was found in 57.14%, coa in 46.42%, mecA in 15.47%, and blaZ in 8.33%. As a result, Staphylococcus spp. strains that were isolated from raw milk in this study contained some virulence factors at a high level, but also contained a relatively low level of beta-lactam resistance genes. However, considering the animal-environment-human interaction, it is considered that the current situation must be monitored constantly in terms of resistance concerns. It must not be forgotten that the development of resistance is in constant change among bacteria.202336978423
2403140.9998Characterization of coagulase-negative staphylococci and macrococci isolated from cheese in Germany. Cheese, especially ripened varieties, harbor a very complex and heterogeneous microbiota. In addition to the desired microorganisms (starter cultures) added during cheese production, potentially harmful bacteria may also enter the production chain. Regarding the latter, the focus of this study was on coagulase-negative staphylococci (CNS) and Macrococcuscaseolyticus. Both are known to harbor a variety of genes coding for antibiotic resistance, including mecA, mecB, mecC, and mecD. Coagulase-negative staphylococci or macrococci carrying such genes or other virulence factors should not be present in cheese. Cheese samples (101 in total) were collected from retail sources. Coagulase-negative staphylococci and M. caseolyticus were isolated utilizing selective agars, and species were identified by phenotypical tests and partial sequencing of the sodA gene. The results allowed identification of 53 CNS strains and 19 M. caseolyticus strains. Among the CNS, 11 isolates of Staphylococcus saprophyticus and one Staphylococcus epidermidis isolate were obtained. Both species are potential human pathogens and may thus adversely affect the safety of these food products. Screening for antimicrobial resistance was performed by application of disc diffusion tests, a gradient strip-test, and 14 different PCR tests. Evidence for methicillin resistance (by either positive disc diffusion assay for cefoxitin or by mec PCR) was found in CNS isolates and M. caseolyticus (9 isolates each). Regarding other virulence factors, no genetic determinants for coagulase or the most common staphylococcal enterotoxins sea, seb, sec, sed, and see were detected in any of the CNS or M. caseolyticus isolates by PCR testing. In conclusion, the presence of facultatively pathogenic CNS and carriers of genes for antibiotic resistance in both groups of microorganisms, especially mec genes, and the respective food safety issues need further evaluation and surveillance.202235965117
2657150.9997Investigating the Prevalence of Enterotoxin and Antibiotic Resistance in Methicillin-Resistant Staphylococcus aureus (MRSA) Isolated From Meat and Edible Viscera of Broiler Chickens. BACKGROUND: The responsible for staph infection is methicillin-resistant Staphylococcus aureus (MRSA) which has a long and difficult treatment process due to resistance to this type of antibiotic. This study is designed to investigate the distribution and frequency of antibiotic-resistant genes and MRSA enterotoxins isolated from the meat and edible viscera of broiler chickens, which are responsible for pathogenicity in humans. MATERIALS AND METHODS: A total of 523 meat and edible viscera of broiler chicken collected from farms in Shahrekord, Iran. The antibiogram test of 142 MRSA isolates was performed by Kirby-Bauer diffusion disc. Sensitivity or resistance of MRSA was tested on 13 different antibiotics. DNA extracted from MRSA was screened by PCR technique for the presence of antibiotic-resistant and enterotoxin genes. RESULTS: Staphylococcus aureus (S. aureus) isolated with frequency of 51.05% (267 of 523). The presence of mecA gene in S. aureus was examined to detect the MRSA. The most antibiotic-resistance responsible genes and the pathogenic enterotoxin genes were identified. MRSA was identified by positive amplification of mecA in 53.18% (142 of 267) of S. aureus isolates. S. aureus antimicrobial resistance was most frequently noted against tetracycline (94.37%), ampicillin (88.73%) and penicillin (71.83%). Out of 51 examined isolates, 47 isolates exhibited the sea (92.15%), and 7 isolates exhibited the sej (13.72%). CONCLUSION: The results indicated high prevalence of MRSA in broilers, which is very worrying issue. In addition, in the present study, it was observed that due to the increase in the use of antibiotics in poultry farming, bacteria resistant to methicillin and other antibiotics have a high prevalence. Now, with the knowledge that the consumption of broiler chicken is very high all over the world and with the increasing trend of antibiotic consumption, this issue has become a concern at the global health level. The presence of antibiotic-resistance and enterotoxigenic genes in MRSA bacteria is a critical threat to human nutrition, making consuming contaminated meat and edible viscera of broiler chickens unsafe.202540613255
2656160.9997Occurrence and Antimicrobial Resistance of Enterococci Isolated from Goat's Milk. INTRODUCTION: Enterococci are widespread, being part of the bacterial flora of humans and animals. The food chain can be therefore considered as the main route of transmission of antibiotic resistant bacteria between the animal and human populations. Milk in particular represents a source from which resistant bacteria can enter the human food chain. The aim of the study was to determine the occurrence and resistance to antimicrobial agents of Enterococcus spp. strains isolated from raw goat's milk samples. MATERIAL AND METHODS: A total of 207 goat's milk samples were collected. Samples were cultivated on selective media and confirmed as E. faecium or E. faecalis and screened for selected resistance genes by PCR. Drug susceptibility determination was performed by microdilution on Sensititre EU Surveillance Enterococcus EUVENC Antimicrobial Susceptibility Testing (AST) Plates and Sensititre US National Antimicrobial Resistance Monitoring System Gram Positive CMV3AGPF AST Plates. RESULTS: Enterococcal strains totalling 196 were isolated, of which 40.8% were E. faecalis and 15.3% were E. faecium. All tested isolates were susceptible to linezolid, penicillin and tigecycline. For most other antimicrobials the prevalence of resistance was 0.5-6.6% while high prevalence of quinupristin/dalfopristin (51.5%), tetracycline (30%) and lincomycin (52%) resistance was observed. CONCLUSION: This study affords better knowledge concerning the safety of raw goat's milk in terms of the enterococci possible to isolate from this foodstuff. It seems that enterococci in milk are still mostly susceptible to antimicrobials of major concern as multiply resisted drugs, such as gentamycin and vancomycin. However, the presence of multi-resistant strains in goat milk is cause for apprehension.202135111998
5601170.9997Presence of Staphylococcus spp. carriers of the mecA gene in the nasal cavity of piglets in the nursery phase. The presence of Staphylococcus spp. resistant to methicillin in the nasal cavity of swine has been previously reported. Considering the possible occurrence of bacterial resistance and presence of resistance genes in intensive swine breeding and the known transmissibility and dispersion potential of such genes, this study aimed to investigate the prevalence of resistance to different antibiotics and the presence of the mecA resistance gene in Staphylococcus spp. from piglets recently housed in a nursery. For this, 60 nasal swabs were collected from piglets at the time of their housing in the nursery, and then Staphylococcus spp. were isolated and identified in coagulase-positive (CoPS) and coagulase-negative (CoNS) isolates. These isolates were subjected to the disk-diffusion test to evaluate the bacterial resistance profile and then subjected to molecular identification of Staphylococcus aureus and analyses of the mecA gene through polymerase chain reaction. Of the 60 samples collected, 60 Staphylococcus spp. were isolated, of which 38 (63.33%) were classified as CoNS and 22 (36.67%) as CoPS. Of these, ten (45.45%) were identified as Staphylococcus aureus. The resistance profile of these isolates showed high resistance to different antibiotics, with 100% of the isolates resistant to chloramphenicol, clindamycin, and erythromycin, 98.33% resistant to doxycycline, 95% resistant to oxacillin, and 85% resistant to cefoxitin. Regarding the mecA gene, 27 (45%) samples were positive for the presence of this gene, and three (11.11%) were phenotypically sensitive to oxacillin and cefoxitin. This finding highlights the importance of researching the phenotypic profile of resistance to different antimicrobials and resistance genes in the different phases of pig rearing to identify the real risk of these isolates from a One Health perspective. The present study revealed the presence of samples resistant to different antibiotics in recently weaned production animal that had not been markedly exposed to antimicrobials as growth promoters or even as prophylactics. This information highlights the need for more research on the possible sharing of bacteria between sows and piglets, the environmental pressure within production environments, and the exposure of handlers during their transport, especially considering the community, hospital, and political importance of the presence of circulating resistant strains.202336634542
2440180.9997Molecular basis of resistance to macrolides, lincosamides and streptogramins in Staphylococcus hominis strains isolated from clinical specimens. Coagulase-negative staphylococci (CoNS) are the most frequently isolated bacteria from the blood and the predominant cause of nosocomial infections. Macrolides, lincosamides and streptogramin B (MLSB) antibiotics, especially erythromycin and clindamycin, are important therapeutic agents in the treatment of methicillin-resistant staphylococci infections. Among CoNS, Staphylococcus hominis represents the third most common organism. In spite of its clinical significance, very little is known about its mechanisms of resistance to antibiotics, especially MLSB. Fifty-five S. hominis isolates from the blood and the surgical wounds of hospitalized patients were studied. The erm(C) gene was predominant in erythromycin-resistant S. hominis isolates. The methylase genes, erm(A) and erm(B), were present in 15 and 25% of clinical isolates, respectively. A combination of various erythromycin resistance methylase (erm) genes was detected in 15% S. hominis isolates. The efflux gene msr(A) was detected in 18% of isolates, alone in four isolates, and in different combinations in a further six. The lnu(A) gene, responsible for enzymatic inactivation of lincosamides was carried by 31% of the isolates. No erythromycin resistance that could not be attributed to the genes erm(A), erm(B), erm(C) and msr(A) was detected. In S. hominis, 75 and 84%, respectively, were erythromycin resistant and clindamycin susceptible. Among erythromycin-resistant S. hominis isolates, 68% of these strains showed the inducible MLSB phenotype. Four isolates harbouring the msr(A) genes alone displayed the MSB phenotype. These studies indicated that resistance to MLSB in S. hominis is mostly based on the ribosomal target modification mechanism mediated by erm genes, mainly the erm(C), and enzymatic drug inactivation mediated by lnu(A).201626253583
2677190.9997Detection of Staphylococcus Isolates and Their Antimicrobial Resistance Profiles and Virulence Genes from Subclinical Mastitis Cattle Milk Using MALDI-TOF MS, PCR and Sequencing in Free State Province, South Africa. Staphylococcus species are amongst the bacteria that cause bovine mastitis worldwide, whereby they produce a wide range of protein toxins, virulence factors, and antimicrobial-resistant properties which are enhancing the pathogenicity of these organisms. This study aimed to detect Staphylococcus spp. from the milk of cattle with subclinical mastitis using MALDI-TOF MS and 16S rRNA PCR as well as screening for antimicrobial resistance (AMR) and virulence genes. Our results uncovered that from 166 sampled cows, only 33.13% had subclinical mastitis after initial screening, while the quarter-level prevalence was 54%. Of the 50 cultured bacterial isolates, MALDI-TOF MS and 16S rRNA PCR assay and sequencing identified S. aureus as the dominant bacteria by 76%. Furthermore, an AMR susceptibility test showed that 86% of the isolates were resistant to penicillin, followed by ciprofloxacin (80%) and cefoxitin (52%). Antimicrobial resistance and virulence genes showed that 16% of the isolates carried the mecA gene, while 52% of the isolates carried the Lg G-binding region gene, followed by coa (42%), spa (40%), hla (38%), and hlb (38%), whereas sea and bap genes were detected in 10% and 2% of the isolates, respectively. The occurrence of virulence factors and antimicrobial resistance profiles highlights the need for appropriate strategies to control the spread of these pathogens.202438200885