Risk factors associated with the antimicrobial resistance of Staphylococcus aureus isolated from bovine mastitis

The objective of this study was to evaluate herd management practices and mastitis treatment procedures as risk factors associated with Staphylococcus aureus antimicrobial resistance. For this study, 13 herds were selected to participate in the study to evaluate the association between their management practices and mastitis treatment procedures and in vitro antimicrobial susceptibility. A total of 1069 composite milk samples were collected aseptically from the selected cows in four different periods over two years. The samples were used for microbiological culturing of S. aureus isolates and evaluation of their antimicrobial susceptibility. A total of 756 samples (70.7%) were culture-positive, and S. aureus comprised 27.77% (n=210) of the isolates. The S. aureus isolates were tested using the disk-diffusion susceptibility assay with the following antimicrobials: ampicillin 10mg; clindamycin 2μg; penicillin 1mg; ceftiofur 30μg; gentamicin 10mg; sulfa-trimethoprim 25μg; enrofloxacin 5μg; sulfonamide 300μg; tetracycline 30μg; oxacillin 1mg; cephalothin 30μg and erythromycin 5μg. The variables that were significantly associated with S. aureus resistance were as follows: the treatment of clinical mastitis for ampicillin (OR=2.18), dry cow treatment for enrofloxacin (OR=2.11) and not sending milk samples for microbiological culture and susceptibility tests, for ampicillin (OR=2.57) and penicillin (OR=4.69). In conclusion, the identification of risk factors for S. aureus resistance against various mastitis antimicrobials is an important information that may help in practical recommendations for prudent use of antimicrobial in milk production.

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Enterotoxins production, biofilm formation and antimicrobial resistance of Staphylococcus aureus strains isolated from refrigerated raw cow milk

Acta Scientiarum Technology ◽

10.4025/actascitechnol.v42i1.45231 ◽

2019 ◽

Vol 42 ◽

pp. e45231

Author(s):

Camila Lampugnani ◽

Maike Taís Maziero Montanhini ◽

Maria Emilene Martino Campos‐Galvão ◽

Luis Augusto Nero ◽

Luciano dos Santos Bersot

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Resistance ◽

Biofilm Formation ◽

Raw Milk ◽

Cow Milk ◽

In Vitro Assays ◽

Vitro Assay ◽

Milk Samples ◽

Adherence Ability

This study aimed to isolate Staphylococcus aureus in refrigerated raw cow milk, and identify the presence of enterotoxin-expression genes, enterotoxin production and adherence ability, and antimicrobial resistance potential of the isolated strains. Fifty raw milk samples obtained in different dairy farms were analyzed for S. aureus and evaluated in the isolates the presence of genes associated with the production of major staphylococcal enterotoxins and biofilm formation. In vitro assays were also performed to evaluate the production of enterotoxins and adherence ability, and the antimicrobial resistance. One half (25/50) of raw milk samples presented coagulase-positive staphylococci and 95.2% of the isolates were confirmed to be S. aureus. Among them, 42.4% were carrying genes for enterotoxins production; however, only one isolate was able to produce enterotoxins. All S. aureus isolates were carrying at least two genes associated with biofilm formation and 95.2% isolates was able to adhere upon the in vitro assay. All isolates demonstrated antimicrobial resistance potential to one or more of the tested antibiotics.

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Salmonella spp. prevalence, antimicrobial resistance and risk factor determination in Colombian swine farms

Pesquisa Veterinária Brasileira ◽

10.1590/1678-5150-pvb-6156 ◽

2019 ◽

Vol 39 (10) ◽

pp. 816-822

Author(s):

Juan P. Giraldo-Cardona ◽

Daniela Gualdrón-Ramírez ◽

Iliana Chamorro-Tobar ◽

Adriana Pulido-Villamarín ◽

Natalia Santamaría-Durán ◽

...

Keyword(s):

Risk Factors ◽

Risk Factor ◽

Antimicrobial Resistance ◽

Antimicrobial Susceptibility ◽

Management Practices ◽

Statistical Significance ◽

Serological Response ◽

Salmonella Spp ◽

Swine Farms ◽

Geographical Regions

ABSTRACT: To determine Salmonella spp. prevalence/seroprevalence, antimicrobial resistance patterns and risk factor identification associated with its presence in Colombian swine farms. 504 samples (Faeces, swabs and environment samples) were obtained from 21 farms distributed in four geographical regions in Colombia. Salmonella spp. microbiological and molecular detection were determined by two Salmonella spp. MDS3M™ and MALDI-TOF MS assays, respectively. In addition, for serological evaluation 231 serum samples were analyzed employing ELISA Salmonella Pigtype®-Salmonella Ab (QUIAGEN®). Additionally, 41 isolates were tested for antimicrobial susceptibility using broth microdilution technique (Panel B1016-180 Beckman Coulter NC72®) and verified with WHONET 2016 software. Risk factors were assessed from a survey and analyzed for statistical significance by U Mann-Whitney test. An 8.9% prevalence (n=45) and 38.1% (n=88) seroprevalence were determined. All isolates presented 100% antimicrobial susceptibility against amikacin. However, resistance against penicillin, tetracycline, cefuroxime and trimethoprim/sulfamethoxazole was present in more than 50% of evaluated strains. Risk factors associated with Salmonella spp. presence were surface water use, rough-surfaced on floors, presence of hoppers as feeders and worker’s boots. Bacteria were present in animals and environmental samples from evaluated farms. Animal contact and/or exposure with the microorganism were also evident in obtained serological response. Bacteria presence depended on management practices and infrastructure, likewise antibiotic use, supplemented in the diet may have induced an increase in Salmonella spp. antimicrobial resistance.

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Molecular Typing and Antimicrobial Susceptibility Profile of Staphylococcus aureus Isolates Recovered from Bovine Mastitis and Nasal Samples

Animals ◽

10.3390/ani10112143 ◽

2020 ◽

Vol 10 (11) ◽

pp. 2143

Author(s):

Renata P. Santos ◽

Fernando N. Souza ◽

Ana Claudia D. Oliveira ◽

Antônio F. de Souza Filho ◽

Juliana Aizawa ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Resistance ◽

Antimicrobial Susceptibility ◽

Molecular Typing ◽

Bovine Mastitis ◽

Aureus Strain ◽

Staphylococcal Protein A ◽

Spa Typing ◽

Intramammary Infections ◽

Antimicrobial Susceptibility Profile

In the present study, we aimed to determine the antimicrobial resistance and molecular typing of Staphylococcus aureus recovered from transient and persistent intramammary infections and nares/muzzles in dairy cows. We investigated the antimicrobial resistance of 189 S. aureus strains using a broad antimicrobial susceptibility profile. Furthermore, 107 S. aureus isolates were strain-typed using staphylococcal protein-A (spa) typing. A large proportion of strains exhibited multidrug resistance to antimicrobials, including resistance to critically important antimicrobials, although no methicillin-resistant S. aureus strains were found. Our study did not strengthen the idea that extramammary niches (i.e., nares/muzzles) are an important source of S. aureus for bovine mastitis. A discrepancy in the antimicrobial resistance between S. aureus strains isolated from nares/muzzles and milk samples was observed. Furthermore, S. aureus isolates from transient and persistent intramammary infections (IMIs) did not differ by spa typing, suggesting that the persistence of bovine IMIs was determined by cow factors. Thus, the high level of multidrug-resistant S. aureus found in the two herds, considered together with the predominance of a well udder-adapted S. aureus strain, may contribute to our knowledge of the history of the high prevalence of mastitis caused by S. aureus, which is of great concern for animal and public health.

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In vitro antimicrobial susceptibility of Staphylococcus aureus strains from dairy herds in KwaZulu-Natal

Journal of the South African Veterinary Association ◽

10.4102/jsava.v82i2.38 ◽

2011 ◽

Vol 82 (2) ◽

Cited By ~ 5

Author(s):

T. Schmidt

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Susceptibility ◽

Bacterial Resistance ◽

Bovine Mastitis ◽

Dairy Industry ◽

Economic Losses ◽

Beta Lactam ◽

Treatment Regimens ◽

High Level

Staphylococcus aureus is 1 of the most important causes of bovine mastitis and is responsible for significant economic losses to the dairy industry worldwide. One of the principal approaches used in treating intramammary infections is the administration of antimicrobials. Due to the propensity of S. aureus to develop resistance, antimicrobial susceptibility monitoring is necessary to ensure that treatment regimens are effective. As part of this investigation, 90 S. aureus strains isolated from mastitis cases submitted to Allerton Provincial Veterinary Laboratory during 2008 and 2009 were evaluated for their susceptibility to a panel of 10 antimicrobials. Only 8 of the 90 S. aureus isolates tested (8.9 %) were found to be susceptible to all of the antimicrobials evaluated. A very high level of resistance to the beta-lactam antibiotics was noted: 47.8 % of the isolates were resistant to penicillin and 65.6 % were resistant to ampicillin. Minimal resistance to oxacillin, cephalothin and trimethoprim-sulfamethoxazole (1.1 %) was found. Seventeen (18.9 %) of the isolates tested were found to be resistant to 3 or more antimicrobials. The need for vigilant monitoring of bacterial resistance trends in the dairy industry is warranted as the potential public health implications are significant.

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Etiology, antimicrobial susceptibility profile of Staphylococcus spp. and risk factors associated with bovine mastitis in the states of Bahia and Pernambuco

Pesquisa Veterinária Brasileira ◽

10.1590/s0100-736x2013000500009 ◽

2013 ◽

Vol 33 (5) ◽

pp. 601-606 ◽

Cited By ~ 4

Author(s):

Carina C. Krewer ◽

Izabela P. de S. Lacerda ◽

Evandro S. Amanso ◽

Noelly B. Cavalcante ◽

Rodolfo de M. Peixoto ◽

...

Keyword(s):

Risk Factors ◽

Antimicrobial Susceptibility ◽

Antimicrobial Agents ◽

Bovine Milk ◽

Bovine Mastitis ◽

Subclinical Mastitis ◽

Control Measures ◽

Factors Associated ◽

Antimicrobial Susceptibility Profile ◽

Staphylococcus Spp

The purpose of this paper was to study the etiology of mastitis, determine the antimicrobial susceptibility profile of Staphylococcus spp. and to identify the risk factors associated with infection in dairy cows in the states of Bahia and Pernambuco, Brazil. From the 2,064 milk samples analyzed, 2.6% were associated with cases of clinical mastitis and 28.2% with subclinical mastitis. In the microbiological culture, Staphylococcus spp. (49.1%) and Corynebacterium spp. (35.3%) were the main agents found, followed by Prototheca spp. (4.6%) and Gram negative bacilli (3.6%). In the antimicrobial susceptibility testing, all 218 Staphylococcus spp. were susceptible to rifampicin and the least effective drug was amoxicillin (32.6%). Multidrug resistance to three or more drugs was observed in 65.6% of Staphylococcus spp. The risk factors identified for mastitis were the extensive production system, not providing feed supplements, teat drying process, not disinfecting the teats before and after milking, and inadequate hygiene habits of the milking workers. The presence of multiresistant isolates in bovine milk demonstrates the importance of the choice and appropriate use of antimicrobial agents. Prophylactic and control measures, including teat antisepsis and best practices for achieving hygienic milking should be established in order to prevent new cases of the disease in herds.

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Prevalence and Antimicrobial Susceptibility Profiles of Pathogen Isolated from Bovine Mastitis Milk in Transylvania, Romania

Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca Veterinary Medicine ◽

10.15835/buasvmcn-vm:12199 ◽

2016 ◽

Vol 73 (2) ◽

pp. 329

Author(s):

Cosmina Bouari ◽

George Nadas ◽

Flore Chirila ◽

Sorin Rapuntean ◽

Cornel Catoi ◽

...

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Clavulanic Acid ◽

Antimicrobial Susceptibility ◽

Bovine Mastitis ◽

Acid Resistance ◽

Diffusion Method ◽

Economic Losses ◽

Disk Diffusion Method

Mastitis in cows, one of the most common and economically important infectious diseases of dairy cattle, all over the world, with significant impact due to economic losses, occurs when the udder becomes inflamed because the leukocytes are released into the mammary gland usually in response to bacteria invasion of the teat canal.The main objective of this study was to evaluate the in vitro antimicrobial susceptibility of bacteria isolated from milk in order to design specific control programs for bovine mastitis in this area.A total of 204 milk samples aseptically collected both from farms and private owners were processed during May 2014 and March 2016 within the Microbiology Laboratory of the Faculty of Veterinary Cluj-Napoca, Romania. The microbiological examination was carried out by inoculation on blood agar and MacConkey medium. After the overnight incubation in aerobic conditions, the identification of the isolates was performed using microscopic, cultural and biochemical methods. Biochemical identification was based on API 20 Biomerieux system. Susceptibility to antibiotics was evaluated using Kirby Bauer disk diffusion method on Mueller-Hinton agar; the antibiotics were represented by Amoxicillin and Clavulanic Acid, Ceftiofur, Florfenicol, Mastidiscs, Enrofloxacin, Penicillin and Tetracycline.Staphylococcus spp. was the most common isolated pathogen, in 54.9% of the specimens, followed by Streptococcus spp. in 20.1%, Escherichia coli in 10.78%, Klebsiella spp. in 8.34%, Bacillus spp. in 5.88%. The most frequent associations were represented by staphylococci-streptococci in 62.7% of the samples, followed by streptococci-bacillus in 19.8% of the samples. The most important etiological agents identified were Staphylococcus aureus, S uberis, Streptococcus agalactiae, and Escherichia coli. Antimicrobial susceptibility test for the total isolates revealed good sensitivity to Enrofloxacin, Mastidiscs and Amoxicillin and Clavulanic Acid. Resistance was observed for Penicillin and Tetracycline.The major mastitis pathogens identified was Staphylococcus aureus, while recurrent mastitis treatment was based on systemic and local administration of Enrofloxacin and Mastidiscs respectively.

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Evolution of In Vitro Antimicrobial Susceptibility of Equine Clinical Isolates in France between 2016 and 2019

Animals ◽

10.3390/ani10050812 ◽

2020 ◽

Vol 10 (5) ◽

pp. 812 ◽

Cited By ~ 1

Author(s):

Albertine Léon ◽

Sophie Castagnet ◽

Karine Maillard ◽

Romain Paillot ◽

Jean-Christophe Giard

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Antimicrobial Resistance ◽

Klebsiella Pneumoniae ◽

Antimicrobial Susceptibility ◽

Diffusion Method ◽

Veterinary Antibiotics ◽

Disk Diffusion Method ◽

Animal Exposure

The present study described the evolution of antimicrobial resistance in equine pathogens isolated from 2016 to 2019. A collection of 7806 bacterial isolates were analysed for their in vitro antimicrobial susceptibility using the disk diffusion method. The most frequently isolated pathogens were group C Streptococci (27.0%), Escherichia coli (18.0%), Staphylococcus aureus (6.2%), Pseudomonas aeruginosa (3.4%), Klebsiella pneumoniae (2.3%) and Enterobacter spp. (2.1%). The majority of these pathogens were isolated from the genital tract (45.1%, n = 3522). With the implementation of two French national plans (named ECOANTIBIO 1 and 2) in 2012–2016 and 2017–2021, respectively, and a reduction in animal exposure to veterinary antibiotics, our study showed decreases in the resistance of group C Streptococci, Klebsiella pneumoniae and Escherichia coli against five classes, four classes and one class of antimicrobials tested, respectively. However, Staphylococcus aureus, Escherichia coli and Enterobacter spp. presented an increased resistance against all the tested classes, excepted for two fifths of E. coli. Moreover, the percentages of multi-drug resistant strains of Staphylococcus aureus and Enterobacter spp. also increased from 24.5% to 37.4% and from 26.3% to 51.7%, respectively. The data reported here are relevant to equine practitioners and will help to improve knowledge related to antimicrobial resistance in common equine pathogens.

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Antimicrobial Susceptibility of Staphylococcus aureus, Streptococcus agalactiae, and Escherichia coli Isolated from Mastitic Dairy Cattle in Ukraine

Antibiotics ◽

10.3390/antibiotics9080469 ◽

2020 ◽

Vol 9 (8) ◽

pp. 469

Author(s):

Leta Elias ◽

Ajay S. Balasubramanyam ◽

Olena Y. Ayshpur ◽

Iryna U. Mushtuk ◽

Nataliya O. Sheremet ◽

...

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Antimicrobial Resistance ◽

Dairy Cattle ◽

Antimicrobial Susceptibility ◽

Streptococcus Agalactiae ◽

Bovine Mastitis ◽

Animal Husbandry ◽

Economic Losses ◽

Susceptibility Profiles

Bovine mastitis is the predominant cause for antimicrobial use on dairy farms and is a major source of economic losses in the dairy industry. In this study, the antimicrobial susceptibility profiles of common mastitis-causing pathogens, Staphylococcus aureus (n = 62), Streptococcus agalactiae (n = 46), and Escherichia coli (n = 129), were determined for dairy cattle with mastitis across 142 Ukrainian farms. The results showed that there were more gentamicin resistant S. aureus isolates (16.95%) identified in this study than previously reported for Ukrainian dairy cattle. Moreover, low levels of amoxicillin susceptibly (13.51%) were observed for St. agalactiae, which contrasted a previous study showing susceptibility levels of >50%. St. agalactiae resistance to tetracycline was observed in 80% of the isolates. Cephalosporin use was most ineffective against E. coli, with 43.27–56% of the isolates exhibiting this resistant trait. Overall, this study performed a preliminary analysis of antimicrobial resistance on mastitis isolates from Ukrainian farms. However, given the limited numbers of the isolates tested in this study and that the publications on antimicrobial resistance in animal husbandry of Ukraine are very few, more extensive investigations are needed to comprehensively examine susceptibility patterns of mastitis-causing pathogens in dairy cattle in Ukraine.

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Prevalence of methicillin-resistant Staphylococcus aureus and pattern of antimicrobial resistance in mastitis milk of cattle in Chitwan, Nepal

BMC Veterinary Research ◽

10.1186/s12917-021-02942-6 ◽

2021 ◽

Vol 17 (1) ◽

Author(s):

Asmita Shrestha ◽

Rebanta Kumar Bhattarai ◽

Himal Luitel ◽

Surendra Karki ◽

Hom Bahadur Basnet

Keyword(s):

Public Health ◽

Staphylococcus Aureus ◽

Antimicrobial Resistance ◽

Subclinical Mastitis ◽

World Health ◽

Dairy Herds ◽

Microbiological Analysis ◽

Biochemical Tests ◽

Methicillin Resistant ◽

Milk Samples

Abstract Background The threat of methicillin-resistant Staphylococcus aureus (MRSA) exists globally and has been listed as a priority pathogen by the World Health Organization. One of the sources of MRSA emergence is livestock and its products, often raised in poor husbandry conditions. There are limited studies in Nepal to understand the prevalence of MRSA in dairy animals and its antimicrobial resistance (AMR) profile. A cross-sectional study was conducted in Chitwan, one of the major milk-producing districts of Nepal, from February 2018 to September 2019 to estimate the prevalence of MRSA in milk samples and its AMR profile. The collected milk samples (n = 460) were screened using the California Mastitis Test (CMT) and positive samples were subjected to microbiological analysis to isolate and identify S. aureus. Polymerase Chain Reaction (PCR) was used to identify the presence of the mecA gene and screen for MRSA. Results In total, 41.5% (191/460) of milk samples were positive in the CMT test. Out of 191 CMT positive milk samples, the biochemical tests showed that the prevalence of S. aureus was 15.2% (29/191). Among the 29 S. aureus isolates, 6.9% (2/29) were identified as MRSA based on the detection of a mecA gene. This indicates that that 1.05% (2/191) of mastitis milk samples had MRSA. The antibiotic sensitivity test showed that 75.9% (22/29) and 48.3% (14/29) S. aureus isolates were found to be sensitive to Cefazolin and Tetracycline respectively (48.3%), whereas 100% of the isolates were resistant to Ampicillin. In total 96.6% (28/29) of S. aureus isolates were multidrug-resistant (MDR). Conclusions This study revealed a high prevalence of S. aureus-mediated subclinical mastitis in dairy herds in Chitwan, Nepal, with a small proportion of it being MRSA carrying a mecA gene. This S. aureus, CoNS, and MRSA contaminated milk poses a public health risk due to the presence of a phenotype that is resistant to very commonly used antibiotics. It is suggested that dairy herds be screened for subclinical mastitis and treatments for the animals be based on antibiotic susceptibility tests to reduce the prevalence of AMR. Furthermore, future studies should focus on the Staphylococcus spp. to explore the antibiotic resistance genes in addition to the mecA gene to ensure public health.

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