Phenotypic and molecular characterization of multidrug-resistant mastitis causing pathogens in dairy cattle. - Related Documents




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267801.0000Phenotypic and molecular characterization of multidrug-resistant mastitis causing pathogens in dairy cattle. This study focused on isolating antibiotic-resistant mastitogens from cow milk; 57% of 100 samples tested positive by California mastitis test. Bacterial species from each milk sample were isolated and identified using Vitek® 2 automated system. Out of the 167 bacterial strains isolated, 14 were multidrug-resistant (MDR) and were further identified as belonging to Staphylococcus spp. Enterobacter spp. Morganella spp. and Elizabethkingia spp. Staphylococcus strains showed the highest resistance by phenotypic and genotypic screening, with 8% of mastitis isolates identified as MDR. These MDR bacterial strains were also found to harbour antibiotic resistance genes such as mecA (21%), blaZ (43%), gyrA (50%), and gyrB (59%). The tissue culture plate assay showed 11 multidrug-resistant bacteria as strong biofilm formers and the biofilm-related atlE gene was analysed from Staphylococcal strain M33.1. The findings highlight a public health risk from resistant dairy bacteria, emphasizing prophylactic measures and responsible antimicrobial use to prevent zoonotic transmission.202541115007
267710.9999Detection 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
235820.9999Genotypic and Phenotypic Evaluation of Biofilm Production and Antimicrobial Resistance in Staphylococcus aureus Isolated from Milk, North West Province, South Africa. Background: Biofilm formation in S. aureus may reduce the rate of penetration of antibiotics, thereby complicating treatment of infections caused by these bacteria. The aim of this study was to correlate biofilm-forming potentials, antimicrobial resistance, and genes in S. aureus isolates. Methods: A total of 64 milk samples were analysed, and 77 S. aureus were isolated. Results: Seventy (90.9%) isolates were biofilm producers. The ica biofilm-forming genes were detected among 75.3% of the isolates, with icaA being the most prevalent (49, 63.6%). The icaB gene was significantly (P = 0.027) higher in isolates with strong biofilm formation potentials. High resistance (60%-90%) of the isolates was observed against ceftriaxone, vancomycin, and penicillin, and 25 (32.5%) of S. aureus showed multidrug resistance (MDR) to at least three antibiotics. Five resistance genes, namely blaZ (29, 37.7%), vanC (29, 37.7%), tetK (24, 31.2%), tetL (21, 27.3%), and msrA/B (16, 20.8%) were detected. Most MDR phenotypes possessed at least one resistance gene alongside the biofilm genes. However, no distinct pattern was identified among the resistance and biofilm phenotypes. Conclusions: The high frequency of potentially pathogenic MDR S. aureus in milk samples intended for human consumption, demonstrates the public health relevance of this pathogen in the region.202032252278
268030.9999Antimicrobial Resistance, Biofilm Formation, and Virulence Genes in Enterococcus Species from Small Backyard Chicken Flocks. Backyard birds are small flocks that are more common in developing countries. They are used for poultry meat and egg production. However, they are also implicated in the maintenance and transmission of several zoonotic diseases, including multidrug-resistant bacteria. Enterococci are one of the most common zoonotic bacteria. They colonize numerous body sites and cause a wide range of serious nosocomial infections in humans. Therefore, the objective of the present study was to investigate the diversity in Enterococcus spp. in healthy birds and to determine the occurrence of multidrug resistance (MDR), multi-locus sequence types, and virulence genes and biofilm formation. From March 2019 to December 2020, cloacal swabs were collected from 15 healthy backyard broiler flocks. A total of 90 enterococci strains were recovered and classified according to the 16S rRNA sequence into Enterococcus faecalis (50%); Enterococcus faecium (33.33%), Enterococcus hirae (13.33%), and Enterococcus avium (3.33%). The isolates exhibited high resistance to tetracycline (55.6%), erythromycin (31.1%), and ampicillin (30%). However, all of the isolates were susceptible to linezolid. Multidrug resistance (MDR) was identified in 30 (33.3%) isolates. The enterococci AMR-associated genes ermB, ermA, tetM, tetL, vanA, cat, and pbp5 were identified in 24 (26.6%), 11 (12.2%), 39 (43.3%), 34 (37.7%), 1 (1.1%), 4 (4.4%), and 23 (25.5%) isolates, respectively. Of the 90 enterococci, 21 (23.3%), 27 (30%), and 36 (40%) isolates showed the presence of cylA, gelE, and agg virulence-associated genes, respectively. Seventy-three (81.1%) isolates exhibited biofilm formation. A statistically significant correlation was obtained for biofilm formation versus the MAR index and MDR. Multi-locus sequence typing (MLST) identified eleven and eight different STs for E. faecalis and E. faecium, respectively. Seven different rep-family plasmid genes (rep1-2, rep3, rep5-6, rep9, and rep11) were detected in the MDR enterococci. Two-thirds (20/30; 66.6%) of the enterococci were positive for one or two rep-families. In conclusion, the results show that healthy backyard chickens could act as a reservoir for MDR and virulent Enterococcus spp. Thus, an effective antimicrobial stewardship program and further studies using a One Health approach are required to investigate the role of backyard chickens as vectors for AMR transmission to humans.202235326843
268140.9999Determination of the Prevalence and Antimicrobial Resistance of Enterococcus faecalis and Enterococcus faecium Associated with Poultry in Four Districts in Zambia. The presence of antimicrobial-resistant Enterococci in poultry is a growing public health concern worldwide due to its potential for transmission to humans. The aim of this study was to determine the prevalence and patterns of antimicrobial resistance and to detect drug-resistant genes in Enterococcus faecalis and E. faecium in poultry from four districts in Zambia. Identification of Enterococci was conducted using phenotypic methods. Antimicrobial resistance was determined using the disc diffusion method and antimicrobial resistance genes were detected using polymerase chain reaction and gene-specific primers. The overall prevalence of Enterococci was 31.1% (153/492, 95% CI: 27.1-35.4). Enterococcus faecalis had a significantly higher prevalence at 37.9% (58/153, 95% CI: 30.3-46.1) compared with E. faecium, which had a prevalence of 10.5% (16/153, 95% CI: 6.3-16.7). Most of the E. faecalis and E. faecium isolates were resistant to tetracycline (66/74, 89.2%) and ampicillin and erythromycin (51/74, 68.9%). The majority of isolates were susceptible to vancomycin (72/74, 97.3%). The results show that poultry are a potential source of multidrug-resistant E. faecalis and E. faecium strains, which can be transmitted to humans. Resistance genes in the Enterococcus species can also be transmitted to pathogenic bacteria if they colonize the same poultry, thus threatening the safety of poultry production, leading to significant public health concerns.202337107019
267550.9998Prevalence and Zoonotic Risk of Multidrug-Resistant Escherichia coli in Bovine Subclinical Mastitis Milk: Insights Into the Virulence and Antimicrobial Resistance. The emergence of antibiotic-resistant microorganisms has made antimicrobial resistance a global issue, and milk is a potential source for the propagation of resistant bacteria causing zoonotic diseases. Subclinical mastitis (SCM) cases, often overlooked and mixed with normal milk in dairy farms, frequently involve E. coli, which can spread through contaminated milk. We conducted this study to determine the prevalence of virulence genes, antibiotic resistance genes (ARGs), antimicrobial susceptibility, and the genetic relatedness of multidrug-resistant (MDR) Shiga toxin-producing E. coli (STEC) isolated from SCM milk. SCM-positive bovine milk was subjected to E. coli detection using cultural, biochemical, and molecular methods. Further, we detected STEC virulence genes including stx1, stx2, and eaeA. STEC isolates were tested for ARGs including blaSHV, CITM, tetA, and aac(3)-IV, and underwent antimicrobial susceptibility tests. Moreover, we performed a phylogenetic analysis of the stx1 gene of MDR-STEC. SCM was detected in 47.2% of milk samples of which 50.54% were E. coli positive. About 17.20% of E. coli isolates contained STEC virulence genes, and stx2 was the most prevalent. Moreover, all STEC isolates harbored at least one of the ARGs, while about 43.75% of the isolates carried multiple ARGs. Additionally, all the STEC isolates showed multidrug resistance, and were found to be fully resistant against amoxicillin, followed by ampicillin (87.50%) and gentamycin (75%); and were mostly sensitive to aztreonam (81.25%) and meropenem (68.75%). In phylogeny analysis, the stx1 gene of isolated MDR-STEC showed close relatedness with disease-causing non-O157 and O157 strains of different sources including cattle, humans, and food.202539816483
297460.9998Diversity of Virulence Genes in Multidrug Resistant Escherichia coli from a Hospital in Western China. BACKGROUND: Escherichia coli strains are the most commonly isolated bacteria in hospitals. The normally harmless commensal E. coli can become a highly adapted pathogen, capable of causing various diseases both in healthy and immunocompromised individuals, by acquiring a combination of mobile genetic elements. Our aim was to characterize E. coli strains from a hospital in western China to determine their virulence and antimicrobial resistance potential. METHODS: A total of 97 E. coli clinical isolates were collected from the First Affiliated Hospital of Chengdu Medical College from 2015 to 2016. Microbiological methods, PCR, and antimicrobial susceptibility tests were used in this study. RESULTS: The frequency of occurrence of the virulence genes fimC, irp2, fimH, fyuA, lpfA, hlyA, sat, and cnf1 in the E. coli isolates was 93.81, 92.78, 91.75, 84.54, 41.24, 32.99, 28.86, and 7.22%, respectively. Ninety-five (97.9%) isolates carried two or more different virulence genes. Of these, 44 (45.4%) isolates simultaneously harbored five virulence genes, 24 (24.7%) isolates harbored four virulence genes, and 17 (17.5%) isolates harbored six virulence genes. In addition, all E. coli isolates were multidrug resistant and had a high degree of antimicrobial resistance. CONCLUSION: These results indicate a high frequency of occurrence and heterogeneity of virulence gene profiles among clinical multidrug resistant E. coli isolates. Therefore, appropriate surveillance and control measures are essential to prevent the further spread of these isolates in hospitals.201931824179
270770.9998Emergence of colistin resistance and characterization of antimicrobial resistance and virulence factors of Aeromonas hydrophila, Salmonella spp., and Vibrio cholerae isolated from hybrid red tilapia cage culture. BACKGROUND: Tilapia is a primary aquaculture fish in Thailand, but little is known about the occurrence of antimicrobial resistance (AMR) in Aeromonas hydrophila, Salmonella spp., and Vibrio cholerae colonizing healthy tilapia intended for human consumption and the co-occurrence of these AMR bacteria in the cultivation water. METHODS: This study determined the phenotype and genotype of AMR, extended-spectrum β-lactamase (ESBL) production, and virulence factors of A. hydrophila, Salmonella spp., and V. cholerae isolated from hybrid red tilapia and cultivation water in Thailand. Standard culture methods such as USFDA's BAM or ISO procedures were used for the original isolation, with all isolates confirmed by biochemical tests, serotyping, and species-specific gene detection based on PCR. RESULTS: A total of 278 isolates consisting of 15 A. hydrophila, 188 Salmonella spp., and 75 V. cholerae isolates were retrieved from a previous study. All isolates of A. hydrophila and Salmonella isolates were resistance to at least one antimicrobial, with 26.7% and 72.3% of the isolates being multidrug resistant (MDR), respectively. All A. hydrophila isolates were resistant to ampicillin (100%), followed by oxytetracycline (26.7%), tetracycline (26.7%), trimethoprim (26.7%), and oxolinic acid (20.0%). The predominant resistance genes in A. hydrophila were mcr-3 (20.0%), followed by 13.3% of isolates having floR, qnrS, sul1, sul2, and dfrA1. Salmonella isolates also exhibited a high prevalence of resistance to ampicillin (79.3%), oxolinic acid (75.5%), oxytetracycline (71.8%), chloramphenicol (62.8%), and florfenicol (55.3%). The most common resistance genes in these Salmonella isolates were qnrS (65.4%), tetA (64.9%), bla (TEM) (63.8%), and floR (55.9%). All V. cholerae isolates were susceptible to all antimicrobials tested, while the most common resistance gene was sul1 (12.0%). One isolate of A. hydrophila was positive for int1, while all isolates of Salmonella and V. cholerae isolates were negative for integrons and int (SXT). None of the bacterial isolates in this study were producing ESBL. The occurrence of mcr-3 (20.0%) in these isolates from tilapia aquaculture may signify a serious occupational and consumer health risk given that colistin is a last resort antimicrobial for treatment of Gram-negative bacteria infections. CONCLUSIONS: Findings from this study on AMR bacteria in hybrid red tilapia suggest that aquaculture as practiced in Thailand can select for ubiquitous AMR pathogens, mobile genetic elements, and an emerging reservoir of mcr and colistin-resistant bacteria. Resistant and pathogenic bacteria, such as resistance to ampicillin and tetracycline, or MDR Salmonella circulating in aquaculture, together highlight the public health concerns and foodborne risks of zoonotic pathogens in humans from cultured freshwater fish.202336855429
119780.9998Sink survey to investigate multidrug resistance pattern of common foodborne bacteria from wholesale chicken markets in Dhaka city of Bangladesh. Antimicrobial resistance (AMR) among foodborne bacteria is a well-known public health problem. A sink survey was conducted to determine the AMR pattern of common foodborne bacteria in cloacal swab of broiler chickens and sewage samples from five wholesale chicken markets of Dhaka city in Bangladesh. Bacteria were identified by culture-based and molecular methods, and subjected to antimicrobial susceptibility testing. Resistance genes were identified by multiplex PCR and sequencing. Multidrug resistance (MDR) was observed in 93.2% of E. coli, 100% of Salmonella spp., and 97.2% of S. aureus from cloacal swab samples. For sewage samples, 80% of E. coli, and 100% of Salmonella and S. aureus showed MDR. Noteworthy, 8.3% of S. aureus from cloacal swab samples showed possible extensively drug resistance. Antimicrobial resistance genes (beta-lactamase-blaTEM, blaSHV; quinolone resistance gene-qnrS) were detected in a number of E. coli and Salmonella isolates from cloacal swab and sewage samples. The methicillin resistance gene (mecA) was detected in 47.2% and 25% S. aureus from cloacal swab and sewage samples, respectively. The findings envisage the potential public health risk and environmental health hazard through spillover of common foodborne MDR bacteria.202235752640
235790.9998Prevalence of Methicillin and β-Lactamase Resistant Pathogens Associated with Oral and Periodontal Disease of Children in Mymensingh, Bangladesh. Oral and periodontal diseases (OPD) is considered one of the main problems of dentistry worldwide. This study aimed to estimate the prevalence of oral and periodontal pathogenic bacteria along with their antimicrobial resistance pattern in 131 children patients aged between 4-10 years who attended in Mymensingh Medical College Hospital during October 2019 to March 2020. OPD pathogens were identified through isolation, cultural and biochemical properties, and nucleic acid detection. The isolates were subjected to antimicrobial susceptibility to 12 antibiotics commonly used in dentistry. In addition, the isolates were analyzed molecularly for the presence of six virulence and three antibacterial resistance genes. Five pathogens were identified, of which Staphylococcus aureus (S. aureus) (49%) and S. salivarius (46%) were noticed frequently; other bacteria included S. mutans (16.8%), S. sobrinus (0.8%) and L. fermentum (13.7%). The virulence genes-clumping factor A (clfA) was detected in 62.5% isolates of S. aureus, and gelatinase enzyme E (gelE) gene was detected in 5% isolates of S. salivarius, while other virulence genes were not detected. All the tested isolates were multidrug-resistant. The overall prevalence of MDR S. aureus, Streptococcus spp. and L. fermentum was 92.2%, 95.1% and 100%, respectively. It was observed that a high proportion of isolates were found resistant to 5-8 antibiotics. A majority of S. aureus, Streptococcus spp., and L. fermentum isolates tested positive for the β-lactamase resistance genes blaTEM and cfxA, as well as the methicillin resistance gene mecA. Phylogenetically, the resistance genes showed variable genetic character among Bangladeshi bacterial pathogens. In conclusion, S. aureus and S. salivarius were major OPD pathogens in patients attended in Mymensingh Medical College Hospital of Bangladesh, and most were Beta-lactam and methicillin resistant.202236015011
2662100.9998Nasal 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
2702110.9998Assessment of the presence of multidrug-resistant Escherichia coli, Salmonella and Staphylococcus in chicken meat, eggs and faeces in Mymensingh division of Bangladesh. The emergence of bacteria that is resistant to several drugs of clinical importance poses a threat to successful treatment, a phenomenon known as multidrug resistance that affects diverse classes of antibiotics. The purpose of this study was to evaluate the prevalence of multidrug-resistant Escherichia coli, Salmonella spp. and Staphylococcus aureus in chicken egg, meat and faeces from four districts of Bangladesh. A total of 120 chicken samples were collected from different poultry farms. Conventional culture and molecular detection methods were used for identification of bacterial isolates from the collected samples followed by antibiotic susceptibility test through the disc diffusion method, finally antibiotic resistant genes were detected by PCR. E. coli, Salmonella spp. and Staphylococcus aureus were detected in meat, egg and faecal samples. Antimicrobial susceptibility results revealed isolates from faeces were 100 % resistant to amoxicillin, while all S. aureus and Salmonella sp. from faeces were resistant to doxycycline, tetracycline and erythromycin. Salmonella spp. isolates from eggs indicated 100 % resistance to erythromycin, amoxycillin, while E. coli were 100 % resistant to erythromycin. E. coli and S. aureus from meat were 100 % resistant to amoxicillin and erythromycin. However, Salmonella spp. from eggs were 100 % susceptible to doxycycline, gentamicin, levofloxacin and tetracycline. The mecA and aac(3)-IV genes were only found in S. aureus and E. coli, respectively. The Sul1, tetB, and aadA1 were highest in Salmonella spp. and S. aureus, while the sul1, tetA and bla (SHV) were higher in E. coli. Isolates from all samples were multidrug resistant. These findings indicate a high risk of transmission of resistance genes from microbial contamination to food of animal origin. The study emphasizes the need for effective biosecurity measures, responsible antibiotic use, and strict regulations in poultry production to prevent the spread of antibiotic resistance.202439281621
2377120.9998Multidrug-resistant and enterotoxigenic methicillin-resistant Staphylococcus aureus isolated from raw milk of cows at small-scale production units. OBJECTIVE: Staphylococcus aureus (S. aureus) has evolved as one of the most significant bacteria causing food poisoning outbreaks worldwide. This study was carried out to investigate the prevalence, antibiotic sensitivity, virulence, and enterotoxin production of S. aureus in raw milk of cow from small-scale production units and house-raised animals in Damietta governorate, Egypt. MATERIAL AND METHODS: The samples were examined bacteriologically, and antimicrobial sensitivity testing was carried out. Moreover, isolates were characterized by the molecular detection of antimicrobial resistance, virulence, and enterotoxin genes. RESULTS: Out of 300 milk samples examined, S. aureus was isolated from 50 samples (16.7%). Antibiotic sensitivity testing revealed that isolates were resistant to β-lactams (32%), tetracycline (16%), and norfloxacin (16%); however, they showed considerable sensitivity to ceftaroline and amikacin (72%). Multidrug-resistance (MDR) has been observed in eight isolates (16%), with a MDR index (0.5) in all of them. Of the total S. aureus isolates obtained, methicillin-resistant S. aureus (MRSA) has been confirmed molecularly in 16/50 (32%) and was found to carry mecA and coa genes, while virulence genes; hlg (11/16, 68.75%) and tsst (6/16, 37.5%) were amplified at a lower percentage, and they showed a significant moderate negative correlation (r = -0.59, p-value > 0.05). Antibiotic resistance genes have been detected in resistant isolates relevant to their phenotypic resistance: blaZ (100%), tetK (50%), and norA (50%). Fifty percent of MRSA isolates carried the seb enterotoxin gene. CONCLUSION: High detection rate of MRSA and MDR isolates from milk necessitates the prompt implementation of efficient antimicrobial stewardship guidelines, especially at neglected small-scale production units.202235445112
1955130.9998Phenotypic & genotypic study of antimicrobial profile of bacteria isolates from environmental samples. BACKGROUND & OBJECTIVES: The resistance to antibiotics in pathogenic bacteria has increased at an alarming rate in recent years due to the indiscriminate use of antibiotics in healthcare, livestock and aquaculture. In this context, it is necessary to monitor the antibiotic resistance patterns of bacteria isolated from the environmental samples. This study was conducted to determine the phenotypic and genotypic profile of antimicrobial resistance in Gram-negative bacteria isolated from environmental samples. METHODS: Two hundred and fifty samples were collected from different sources, viz. fish and fishery products (99), livestock wastes (81) and aquaculture systems (70), in and around Mangaluru, India. Isolation, identification and antimicrobial profiling were carried out as per standard protocols. The isolates were screened for the presence of resistance genes using PCR. RESULTS: A total of 519 Gram-negative bacteria comprising Escherichia coli (116), Salmonella spp. (14), Vibrio spp. (258), Pseudomonas spp. (56), Citrobacter spp. (26) and Proteus spp. (49) were isolated and characterized from 250 samples obtained from different sources. A total of 12 antibiotics were checked for their effectiveness against the isolates. While 31.6 per cent of the isolates were sensitive to all the antibiotics used, 68.4 per cent of the isolates showed resistance to at least one of the antibiotics used. One-third of the isolates showed multidrug resistance. Maximum resistance was observed for ampicillin (43.4%), followed by nitrofurantoin (20.8%). Least resistance was seen for carbapenems and chloramphenicol. PCR profiling of the resistant isolates confirmed the presence of resistance genes corresponding to their antibiotic profile. INTERPRETATION & CONCLUSIONS: This study results showed high rate of occurrence of antimicrobial resistance and their determinants in Gram-negative bacteria isolated from different environmental sources.201931219088
2972140.9998Genetic characterisation of class 1 integrons among multidrug-resistant Salmonella serotypes in broiler chicken farms. OBJECTIVES: Antimicrobial resistance in Salmonella serotypes has been reported. Integrons play an important role in the dissemination of antimicrobial resistance genes in bacteria. Scarce literature is available on the identification of integrons in Salmonella isolated from broiler chickens. In this study, antimicrobial susceptibility testing and characterisation of class 1 integrons among multidrug-resistant (MDR) Salmonella enterica serotypes in broiler chicken farms in Egypt were performed. METHODS: Antimicrobial susceptibility was determined by the disk diffusion method. PCR was performed to detect antimicrobial resistance genes and class 1 integrons in the tested Salmonella serotypes. Gene sequencing of the variable region of a class 1 integron was performed. RESULTS: Salmonella spp. were detected in 26 (13.5%) of 192 broiler samples, with Salmonella Enteritidis being the most frequently detected serotype, followed by Salmonella Kentucky and Salmonella Typhimurium and other serotypes. A very high resistance rate was observed to trimethoprim/sulfamethoxazole (100%), whilst a low resistance rate was observed to cefuroxime (57.7%). MDR S. enterica isolates displayed resistance to ciprofloxacin and azithromycin. Class 1 integrons were detected in 20 (76.9%) of the 26 Salmonella isolates. A high prevalence of class 1 integrons, as the first recorded percentage in the literature, associated with MDR Salmonella isolates was observed. CONCLUSIONS: Antimicrobial resistance rates in Salmonella serotypes from broiler chicken farms were alarming, especially for ciprofloxacin and azithromycin. Thus, another therapeutic strategy other than antimicrobials is recommended to prevent outbreaks of MDR Salmonella.201829684574
1286150.9998High prevalence of antibiotic resistance in pathogenic foodborne bacteria isolated from bovine milk. This study aimed to investigate the prevalence of foodborne pathogenic bacteria in bovine milk, their antibiogram phenotype, and the carriage of antibiotic resistance genes. Raw bovine milk samples (n = 100) were randomly collected from different suppliers in the northwest of Iran. Antibiotic-resistant patterns and the presence of antibiotic resistance genes were evaluated in the isolates. Escherichia coli, Listeria monocytogenes, Staphylococcus aureus, and Salmonella spp. were isolated from 78%, 47%, 25%, and 21% of samples, respectively. All isolates showed high rates of resistance to amoxicillin, penicillin, and cefalexin. The bla(TEM) and bla(SHV) genes were detected in 50.0% and 6.4% of E. coli isolates, respectively. Also, 28.5% and 19.0% of Salmonella isolates were positive for bla(TEM) and bla(SHV). The frequency of mecA and bla(Z) in S. aureus isolates was 20.0% and 12.0%, respectively. The high prevalence of bovine milk contamination with antimicrobial-resistant species in this study necessitates precise control on antibiotic prescription in veterinary medicine.202235264647
2967160.9998Antibiotic susceptibility and prevalence of foodborne pathogens in poultry meat in Romania. INTRODUCTION: The occurrence of pathogenic strains in poultry meat is of growing concern in Romania. Another problem found on a global level is the continuous increase of antimicrobial resistance in bacteria isolated from food. This study aimed to evaluate the prevalence of pathogenic bacteria in poultry carcasses obtained in Romania in 2012-2013 and to reveal the most prevalent patterns of antimicrobial resistance in the isolated strains. METHODOLOGY: A total of 144 broiler chicken carcasses were evaluated according to classical microbiological methods. The DNA was extracted from the bacterial colonies and the resistance genes were identified by PCR. RESULTS: In 2012, 47.2% of the samples revealed at least one of the following bacteria: Campylobacter jejuni (9.72%; n = 7), Salmonella enterica serotype Enteritidis (4.17%; n = 3), Listeria monocytogenes (15.28%; n = 11), and Escherichia coli (16.67%; n = 12). In 2013, the number of positive samples of pathogenic bacteria decreased, although Campylobacter jejuni was isolated in a higher percentage (20.8% vs. 9.72%). The percentage of multidrug-resistant (MDR) bacteria was high (23%); the most prevalent pattern included resistance to tetracycline, sulfonamides, and quinolones/fluoroquinolones. All the resistant Salmonella and E. coli strains were tested for the presence of characteristic resistance genes (Kn, bla(TEM), tetA, tetB, tetG, DfrIa, aadA1a, Sul) and revealed that these isolates represent an important reservoir in the spread of this phenomenon. CONCLUSIONS: Our findings suggest that Romania urgently needs an integrated surveillance system within the entire chain, for drug-resistant pathogens isolated from poultry meat.201525596569
2670170.9998Molecular characterisation and antimicrobial resistance of Streptococcus agalactiae isolates from dairy farms in China. INTRODUCTION: Streptococcus agalactiae (S. agalactiae) is a pathogen causing bovine mastitis that results in considerable economic losses in the livestock sector. To understand the distribution and drug resistance characteristics of S. agalactiae from dairy cow mastitis cases in China, multilocus sequence typing (MLST) was carried out and the serotypes and drug resistance characteristics of the bacteria in the region were analysed. MATERIAL AND METHODS: A total of 21 strains of bovine S. agalactiae were characterised based on MLST, molecular serotyping, antimicrobial susceptibility testing, and the presence of drug resistance genes. RESULTS: The serotypes were mainly Ia and II, accounting for 47.6% and 42.9% of all serotypes, respectively. Five sequence types (STs) were identified through MLST. The ST103 and ST1878 strains were predominant, with rates of 52.4% and 28.6%, respectively. The latter is a novel, previously uncharacterised sequence type. More than 90% of S. agalactiae strains were susceptible to penicillin, oxacillin, cephalothin, ceftiofur, gentamicin, florfenicol and sulfamethoxazole. The bacteria showed high resistance to tetracycline (85.7%), clindamycin (52.1%) and erythromycin (47.6%). Resistant genes were detected by PCR, the result of which showed that 47.6%, 33.3% and 38.1% of isolates carried the tet(M), tet(O) and erm(B) genes, respectively. CONCLUSION: The results of this study indicate that S. agalactiae show a high level of antimicrobial resistance. It is necessary to monitor the pathogens of mastitis to prevent the transmission of these bacteria.202338143824
2667180.9998Prevalence, virulence and antimicrobial resistance patterns of Aeromonas spp. isolated from children with diarrhea. BACKGROUND: Aeromonas spp. cause various intestinal and extraintestinal diseases. These bacteria are usually isolated from fecal samples, especially in children under five years old. The aim of this study was to assess the prevalence of Aeromonas spp. and their antimicrobial resistance profile in children with diarrhea referred to the Children Medical Center in Tehran, between 2013 and 2014. METHODS: A total number of 391 stool samples were collected from children with ages between 1 day and 14 years old, with diarrhea (acute or chronic), referred to the Children Hospital, Tehran, Iran, between 2013 and 2014. Samples were enriched in alkaline peptone water broth for 24 hours at 37 °C and then cultured. Suspicious colonies were analyzed through biochemical tests. Furthermore, antimicrobial susceptibility tests were carried out for the isolates. Isolates were further studied for act, ast, alt, aerA and hlyA virulence genes using polymerase chain reaction. RESULTS: In total, 12 isolates (3.1%) were identified as Aeromonas spp.; all were confirmed using the API-20E test. Of these isolates, five A. caviae (42%), four A. veronii (33%) and three A. hydrophila (25%) were identified in cases with gastroenteritis. Second to ampicillin (which was included in the growth medium used), the highest rate of antimicrobial resistance was seen against nalidixic acid and trimethoprim-sulfamethoxazole (5 isolates each, 41.6%) and the lowest rate of antimicrobial resistance was seen against gentamicin, amikacin and cefepime (none of the isolates). Results included 76.4% act, 64.7% ast, 71.5% alt, 83.3% aerA and 11.7% hlyA genes. CONCLUSION: Aeromonas spp. are important due to their role in diarrhea in children; therefore, isolation and identification of these fecal pathogens should seriously be considered in medical laboratories. Since virulence genes play a significant role in gastroenteritis symptoms caused by these bacteria, Aeromonas species that include virulence genes are potentially suspected to cause severe infections. Moreover, bacterial antimicrobial resistance is increasing, especially against trimethoprim-sulfamethoxazole and nalidixic acid.201627622161
2706190.9998Prevalence and antimicrobial resistance profile of bacterial foodborne pathogens in Nile tilapia fish (Oreochromis niloticus) at points of retail sale in Nairobi, Kenya. Proteus spp., Staphylococcus spp., Pseudeomonas spp., and pathogenic Vibrios are among the major foodborne pathogens associated with the consumption of contaminated fish. The increasing occurrence of antimicrobial resistance in these pathogens is a serious public health concern globally and therefore continuous monitoring of antimicrobial resistance of these bacteria along the food chain is crucial for for control of foodborne illnesses. The aim of this study was to assess the prevalence, antimicrobial resistance patterns, antibiotic resistance genes, and genetic diversity of bacterial foodborne pathogens recovered from fresh Nile tilapia (Oreochromis niloticus) obtained from retail markets in Nairobi, Kenya. A total of 68 O. niloticus fish with an average weight of 300.12 ± 25.66 g and body length of 23.00 ± 0.82 cm were randomly sampled from retail markets and tested for the presence of Proteus, Staphylococcus aureus, Pseudomonas aeruginosa, Vibrio cholerae, and Vibrio parahaemolyticus. Standard culture-based microbiological and Kirby-Bauer agar disk diffusion methods were used to isolate and determine the antimicrobial resistance patterns of the isolates to 11 selected antibiotics. Statistical analysis was performed using Minitab v17.1, with p < 0.05 considered significant. The genetic diversity of the multidrug-resistant (MDR) and extensively drug-resistant (XDR) bacteria was determined using 16S rRNA sequencing and phylogenetic analysis, and polymerase chain reaction (PCR) was used for detection of antibiotic resistance genes in MDR bacterial isolates. High levels of bacterial contamination were detected in fresh O. niloticus fish (44/68, 64.71%). The most prevalent bacteria were Proteus spp. (44.12%), with the rest of the bacterial species registering a prevalence of 10.29%, 4.41%, 2.94%, and 2.94% (for S. aureus, P. aeruginosa, V. cholerae, and V. parahaemolyticus, respectively). Antimicrobial resistance was detected in all the bacteria species and all the isolates were resistant to at least one antibiotic except cefepime (30 µg). Additionally, 86.36% of the isolates exhibited multidrug resistance, with higher multiple antibiotic resistance indices (MAR index >0.3) indicating that fresh O. niloticus fish were highly contaminated with MDR bacteria. Results of 16S rRNA sequences, BLASTn analysis, and phylogenetic trees confirmed the identified MDR bacterial isolates as Proteus mirabilis and other Proteus spp., S. aureus, P. aeruginosa, V. cholerae, and V. parahaemolyticus. PCR analysis confirmed the presence of multiple antibiotic resistance genes blaTEM-1, blaCMY-2, tetA, tetC, Sul2, dfrA7, strA, and aadA belonging to β-lactamases, tetracycline, sulfonamide, trimethoprim, and aminoglycosides in all the MDR bacterial isolates. There was strong correlation between antibiotic- resistant genes and phenotypic resistance to antibiotics of MDR bacteria. This study showed high prevalence of multidrug resistance among foodborne bacterial isolates from fresh O. niloticus fish obtained from retail markets. From this study, we conclude that fresh O. niloticus fish are a potential source of MDR bacteria, which could be a major risk to public health as a consequence of their dissemination along the human food chain. These results highlight the prevalence of antimicrobial-resistant foodborne pathogens in fish purchased from retail markets and underscore the risk associated with improper handling of fish.202339816642