scholarly journals Molecular characterization of virulence factors in Staphylococcus aureus isolated from bovine subclinical mastitis in central Ethiopia

2021 ◽  
Vol 71 (1) ◽  
Author(s):  
Desiye Tesfaye Tegegne ◽  
Gezahegne Mamo ◽  
Hika Waktole ◽  
Yohannes Equar Messele
Keyword(s):  
Staphylococcus Aureus ◽  
Dairy Cows ◽  
Virulence Factors ◽  
Virulence Genes ◽  
Animal Health ◽  
Subclinical Mastitis ◽  
Biochemical Tests ◽  
Milk Samples ◽  
Lactating Dairy Cows ◽  
Genomic Study

Abstract Purpose Staphylococcus aureus (S. aureus) is the most important pathogen involved in bovine mastitis in dairy production. S. aureus produces a spectrum of extracellular protein toxins and virulence factors which are thought to contribute to the pathogenicity of the organism. The aim of this work was to isolate and molecular characterize S. aureus associated with bovine subclinical mastitis in the central part of Ethiopia. Methods A total of 265 lactating dairy cows from various dairy farms in four different geographical locations were screened by the California mastitis test (CMT) for bovine subclinical mastitis. One hundred thirty CMT-positive milk samples were collected and transported to the laboratory. Different biochemical tests and polymerase chain reaction (PCR) were used for the identification of S. aureus isolates. Finally, PCR was performed for molecular detection of virulence genes. Results From a total of 265 lactating dairy cows screened, 49% (n = 130) were positive for bovine subclinical mastitis. One hundred thirty mastitic milk samples were subjected to bacterial culturing, and one hundred (76%) S. aureus isolates were identified based on phenotypic characters. Sixty-eight confirmed S. aureus isolates were obtained using PCR. The confirmed S. aureus isolates were tested for six virulence genes (tsst-1, hlb, eta, sea, clfA, and icaD) using PCR. Of the six virulence genes screened from all the isolates, only two (clfA and eta) were detected in the isolates. Out of 68 isolates, 25% and 22% were possessed the eta and clfA genes, respectively. Conclusion The presence of Staphylococcus aureus having virulence genes (eta and clfA) revealed that mastitis is a major concern nowadays affecting animal health, milk quality, and yield. Further genomic study of these isolates will provide broad new insights on virulence.

scholarly journals Molecular characterization of virulence factors in Staphylococcus aureus isolated from bovine subclinical mastitis in central Ethiopia

2021 ◽  
Author(s):  
Desiye Tesfaye Teegegne ◽  
Gezahegne Mamo ◽  
Hika Waktole ◽  
Yohannes Equar Messele
Keyword(s):  
Staphylococcus Aureus ◽  
Dairy Cows ◽  
Virulence Factors ◽  
Virulence Genes ◽  
Animal Health ◽  
Subclinical Mastitis ◽  
Biochemical Tests ◽  
Milk Samples ◽  
Lactating Dairy Cows ◽  
Genomic Study

Abstract Purpose: Staphylococcus aureus (S. aureus) is the most important pathogen involved in bovine mastitis in dairy production. S. aureus produces a spectrum of extracellular protein toxins and virulence factors which are thought to contribute to the pathogenicity of the organism. The aim of this work was to isolate and molecular characterize S. aureus associated with bovine subclinical mastitis in central part of Ethiopia.Methods: A total of 265 lactating dairy cows from various dairy farms in four different geographical locations were screened by California mastitis test (CMT) for bovine subclinical mastitis. One-hundred thirty CMT positive milk samples were collected and transported to laboratory. Different biochemical tests and polymerase chain reaction (PCR) were used for the identification of S. aureus isolates. Finally, PCR was performed for molecular detection of virulence genes. Results: From total of 265 lactating dairy cows screened, 49% (n=130) were positive for bovine subclinical mastitis. One-hundred thirty mastitic milk samples were subjected to bacterial culturing, one hundred (76%) S. aureus isolates were identified based on phenotypic characters. Sixty-eight confirmed S. aureus isolates were obtained using PCR. The confirmed S. aureus isolates were tested for six virulence genes (tsst-1, hlb, eta, sea, clfA and icaD) using PCR. Of the six virulence genes screened from all the isolates, only two (clfA and eta) were detected in the isolates. Out of 68 isolates, 25% and 22% were possessed the eta and clfA genes, respectively. Conclusion: Presence of Staphylococcus aureus having virulence genes (eta and clfA) revealed that mastitis is a major concern nowadays affecting animal health, milk quality, and yield. Further genomic study of these isolates will provide broad new insights on virulence.

scholarly journals Staphylococcus aureus isolates from bovine subclinical mastitis in central Ethiopia revealed the presence of antimicrobial resistance and resistant genes

2021 ◽  
Author(s):  
Desiye Tesfaye Tegegne ◽  
Gezahegne Mamo ◽  
Hika Waktole ◽  
Gebrerufael Girmay
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Resistance ◽  
Dairy Cows ◽  
Resistance Genes ◽  
Dairy Farms ◽  
Subclinical Mastitis ◽  
Economic Losses ◽  
Central Ethiopia ◽  
Milk Samples ◽  
Lactating Dairy Cows

Abstract Background: Staphylococcus aureus is one of the predominant causative agents of mastitis disease in dairy herds. Mastitis disease has a negative impact in the economic losses in the dairy sector across the globe. The aims of this study were to determine the prevalence and detect antimicrobial resistance genes in the Staphylococcus aureus isolated from milk samples of subclinical bovine mastitis in Central Ethiopia.Methods: A total of 265 lactating dairy cows from various dairy farms in four different geographical locations were screened by California mastitis test (CMT) for bovine subclinical mastitis. One-hundred thirty CMT positive milk samples were collected and transported to laboratory. Different biochemical tests and polymerase chain reaction (PCR) were used for the identification of S. aureus isolates. Finally, phenotypic and genotypic methods were performed for detection of some antimicrobial resistance patterns and genes (mecA, ermA, ermC, and msrA), respectively. Results: From total of 265 lactating dairy cows screened, 49% (n=130) were positive for bovine subclinical mastitis. One-hundred thirty mastitic milk samples were subjected to bacterial culturing, one hundred (76%) S. aureus isolates were identified based on phenotypic characters. Sixty-eight confirmed S. aureus isolates were obtained using PCR. Of the sixty-eight isolates tested 12 samples were contained the methicillin resistance gene A (mecA). No amplification was observed for the erythromycin resistance genes (ermA, ermC, and msrA). Conclusion: The high resistance of Staphylococcus aureus to commonly used antimicrobials contribute in dairy farms may cause health problems in the community consuming raw milk purchased from these farms.

scholarly journals Prevalence of enterotoxins and other virulence genes of Staphylococcus aureus caused subclinical mastitis in dairy cows

2020 ◽  
Vol 13 (6) ◽  
pp. 1193-1198
Author(s):  
Rania M. Ewida ◽  
Amira A. T. Al-Hosary
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factors ◽  
Toxic Shock Syndrome ◽  
Virulence Genes ◽  
Dairy Farms ◽  
Subclinical Mastitis ◽  
Enterotoxin Gene ◽  
Toxic Shock ◽  
Milk Samples ◽  
Dairy Animals

Background and Aim: Milk production is one of the main props for the national economy. One of the crucial problems in this industry is subclinical mastitis, which harms this industry that considered the backbone of the economy. It is an infectious and zoonotic disease; the infection can spread between dairy animals through milkers' hands, and milking machines, while the human infection occurs due to the consumption of apparently hygienic milk. Staphylococcus aureus is one of the main causative agents of clinical and subclinical mastitis. It is also considered one of the bacteria incriminated in food intoxication of humans due to its virulence factors as enterotoxins and toxic shock syndrome. The current study was designed to assess the prevalence of S. aureus and its enterotoxins, as well as, its other virulence factors in milk collected from cows that suffer from subclinical mastitis. Materials and Methods: Sixty cows were collected from different dairy farms located in Assiut Governorate, Egypt. These cows were subjected to the clinical examination of the udder and its lymph nodes before sampling. Milk samples were collected from clinically healthy udders. All the milk samples were examined by California mastitis test (CMT), polymerase chain reaction (PCR), and enzyme-linked immunosorbent assay (ELISA) for confirmation subclinical mastitis, presence of S. aureus and its enterotoxins genes and other virulence factors in the examined milk samples. Results: The cows included in the current study had healthy udders. The sixty collected milk samples were tested by CMT. 48/60 (80.0%) were positive samples; from the 48 positive samples, 46 (95.83%) samples were confirmed positive by S. aureus 16s rRNA PCR assay. Multiplex PCRs confirmed the presence of staphylococcus enterotoxin gene C (sec) in one sample, staphylococcus enterotoxin gene D (sed) in 23 samples, while ELISA assay confirmed the presence of the same enterotoxin in only two samples. On the other hand, other groups of genes responsible for some other virulence factors of S. aureus like the extracellular thermostable nuclease (nuc) gene were found in 33 samples, while toxic shock syndrome (tsst) gene and methicillin restraint S. aureus (mecA) gene were not detected in this study. Conclusion: Subclinical mastitis is one of the hidden factors that adversely affect the health of both animals and humans. The milk is usually appeared good and may be consumed by humans especially children; however, it causes severe public health problems. In addition, the infected animals with this form of mastitis can spread the infection to other dairy animals and may be turned to a clinical case of contagious mastitis that may be ended by animal culling or death. S. aureus is one of the main causes of subclinical mastitis in cattle. In addition to extracellular thermostable nuclease (nuc) gene, staphylococcus enterotoxin gene C (sec) and staphylococcus enterotoxin gene D (sed) are the most common virulence genes confirmed in subclinical mastitis milk. These results highlighted the need to apply more hygienic measures in the dairy farms to avoid spreading the infection between animals to ensure the production of safe and healthy food to humans.

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

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.

scholarly journals Subclinical mastitis in dairy cows: somatic cell counts and associated bacteria in Mymensingh, Bangladesh

2017 ◽  
Vol 15 (2) ◽  
Author(s):  
SMMR Sumon ◽  
MA Ehsan ◽  
MT Islam
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Dairy Cows ◽  
Subclinical Mastitis ◽  
Mixed Infections ◽  
Coagulase Negative Staphylococci ◽  
Somatic Cell Counts ◽  
Milk Samples ◽  
Cell Counts ◽  
Bacillus Spp

Subclinical mastitis is an economically important disease of dairy cows and has a prominent place amongst the factors that limit milk production. This study was undertaken to determine the association of somatic cell counts (SCC) and occurrence of bacteria with SCM in smallholder dairy cows in Mymensingh, Bangladesh. A total number of 240 quarters milk samples from apparently healthy lactating cows were subjected to SCC using NucleoCounter® SCC-100 ™ (Chemo Metec). A quarter was considered SCM positive if the quarter had SCC>100 x 103 cells/ml. All subclinical mastitis positive quarter milk samples were subjected to bacteriological examination and isolates were classified into major, minor, uncommon and mixed pathogens. The overall quarter-level prevalence of subclinical mastitis of dairy cows in Mymensingh district was 25% (95% CI, 19.52% to 30.48%). The most frequently isolated bacterial species were Staphylococcus aureus (18.33%) followed by coagulase-negative staphylococci (10%), Enterobacter spp. (6.67%), Escherichia coli (5%), Bacillus spp. (5%) and Pseudomonas aeruginosa (5%). Different bacterial isolates were associated with 90% cases of subclinical mastitis as mono infections or mixed infections. Mono and mixed infections significantly influenced SCC and were the most prominent factors responsible for increasing SCC. Mean SCC was the highest for Bacillus spp. (713.67 x 103 cells/ml) followed by Enterobacter spp. (395.75 x 103 cells/ml), Escherichia coli (386.00 x 103 cells/ml), Staphylococcus aureus (373.82 x 103 cells/ml), coagulase-negative staphylococci (182.67 x 103 cells/ml) and Pseudomonas aeruginosa (138.67 x 103 cells/ml). Major pathogens induced higher SCC (380.72 x 103cells/ml) than minor and other pathogen groups.J. Bangladesh Agril. Univ. 15(2): 266-271, December 2017

scholarly journals Prevalence, antibiotic resistance, virulence and genetic diversity of Staphylococcus aureus isolated from bulk tank milk samples of U.S. dairy herds

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Kruthika Patel ◽  
Sandra M. Godden ◽  
Erin E. Royster ◽  
Brian A. Crooker ◽  
Timothy J. Johnson ◽  
...  
Keyword(s):  
Public Health ◽  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Dairy Cows ◽  
Virulence Genes ◽  
Dairy Herds ◽  
Drug Resistant ◽  
Bulk Tank Milk ◽  
Milk Samples ◽  
Bulk Tank

Abstract Background Colonization of dairy cows by Staphylococcus aureus (S. aureus), especially those which are multi-drug resistant and toxin producing, is a concern for animal health and well-being as well as public health. The objective of this study was to investigate the prevalence, antibiotic resistance, gene content and virulence determinants of S. aureus in bulk tank milk samples (BTM) from U.S. dairy herds. Results BTM samples were collected, once in winter and once in summer, from 189 U.S. dairy herds. Of 365 BTM samples cultured, the sample and herd prevalence of S. aureus in BTM was 46.6% (170 of 365 samples) and 62.4% (118 of 189 herds), respectively. Among a subset of 138 S. aureus isolates that were stored for further analysis, 124 were genome sequenced after being confirmed as S. aureus using phenotypic tests. The most commonly identified antimicrobial resistance-associated gene was norA (99.2%) and mecA gene responsible for methicillin resistance (MRSA) was identified in one isolate (0.8%). The most frequently detected putative virulence genes were aur (100%), hlgB (100%), hlgA, hlgC, hlb (99.2%), lukE (95.9%) and lukD (94.3%). In the 53 staphylococcal enterotoxin positive isolates, sen (37.9%), sem (35.5%), sei (35.5%) and seg (33.1%) were the most frequently detected enterotoxin genes. Among the 14 sequence types (ST) and 18 spa types identified, the most common was ST2187 (20.9%) and t529 (28.2%), respectively. The most predominant clone was CC97 (47.6%) followed by CC unknown (36.3%). The single MRSA isolate belonged to ST72-CC8, spa type t126 and was negative for the tst gene but harbored all the other virulence genes investigated. Conclusion Our findings indicated a high prevalence of S. aureus in BTM of U.S. dairy herds, with isolates showing little evidence of resistance to antibiotics commonly used to treat mastitis. However, isolates often carried genes for the various enterotoxins. This study identified predominant genetic clones. Despite lower prevalence, the presence of MRSA and multi-drug resistant strains in BTM poses a significant risk to animal and public health if their number were to increase in dairy environment. Therefore, it is necessary to continuously monitor the use of antibiotics in dairy cows.

scholarly journals Evaluation of the Prevalence of Subclinical Mastitis in Dairy Cattle in the Soummam Valley (Bejaia, Algeria)

2019 ◽  
Vol 76 (2) ◽  
pp. 143
Author(s):  
Asma Ait KAKI ◽  
Salem DJEBALA ◽  
Muhammad Bilal LATIF ◽  
Nassim MOULA
Keyword(s):  
Staphylococcus Aureus ◽  
Mammary Gland ◽  
Dairy Cattle ◽  
Dairy Cows ◽  
Farming System ◽  
Subclinical Mastitis ◽  
Bacterial Strains ◽  
Milk Samples ◽  
California Mastitis Test ◽  
Bacterium Species

The present study was carried out to investigate the prevalence of subclinical mastitis (SCM) in milking cows and the effect of farming system on the prevalence of SCM”, as well as the identification of bacterial strains causing the mammary gland infection. A total of 100 dairy cows were randomly selected from 32 farms of Bejaia district (Algeria), precisely the Soummam region: from Tazmalt to El Kseur. The SCM was screened by California Mastitis Test (CMT). Milk samples were collected aseptically from (CMT) positive cows and dispatched to laboratory for further microbiological tests. Results showed that the prevalence of SCM was 26%. Moreover, no significant differences in SCM prevalence were observed between intensive and semi intensive systems (P>0.05). The Staphylococcus aureus was found to be the most frequent bacterium species associated with SCM in the cows studied.

scholarly journals Efficacy of novel antiseptic product containing essential oil of Lippia origanoides to reduce intramammary infections in cows

2020 ◽  
Vol 13 (11) ◽  
pp. 2452-2458
Author(s):  
Natalia Arantes Marcelo ◽  
Viviane Aguiar Andrade ◽  
Cintya Neves Souza ◽  
Rodrigo Pereira Mourão ◽  
Mário Henrique França Mourthe ◽  
...  
Keyword(s):  
Essential Oil ◽  
Dairy Cows ◽  
Conventional Treatment ◽  
Experimental Treatment ◽  
Subclinical Mastitis ◽  
Coagulase Negative Staphylococcus ◽  
Biochemical Tests ◽  
Intramammary Infections ◽  
Milk Samples ◽  
Alternative Product

Background and Aim: The use of antimicrobials in the control of mastitis is of concern in public health due to their inefficiency in targeting microorganisms. Studies with medicinal plants have risen as an alternative to the use of conventional products. The objective of this study was to evaluate the efficacy of an experimental disinfectant based on the essential oil (EO) from Lippia origanoides in preventing the development of new intramammary infections (IMI) in Holstein cows. Materials and Methods: The conventional protocol of pre- and post-milking was used and the control (Conventional treatment [CNV]) and experimental (Experimental treatment [PEX]) products containing EO at 120 μL/mL were applied by immersion. Individual milk samples were analyzed using sheep blood agar methodologies and biochemical tests. The efficiency of the treatment was defined by the presence or absence of Staphylococcus aureus, coagulase-negative Staphylococcus, and Streptococcus spp. Results: There were no clinical and subclinical mastitis cases, no lesions in the mucosal of teats, nor dirt score between groups in this study. Both treatments did not influence the occurrence of IMI. Conclusion: The results revealed that PEX acts efficiently against microorganisms compared to the disinfection by the conventional product demonstrating the efficacy of the alternative product on the prevention of new IMIs in dairy cows.

scholarly journals Isolation of Yersinia pseudotuberculosis in bovine mastitis: A potential milk-borne hazard

2021 ◽  
Vol 9 (4) ◽  
Author(s):  
Andrea Lorusso ◽  
Luciana Addante ◽  
Loredana Capozzi ◽  
Angelica Bianco ◽  
Laura Del Sambro ◽  
...  
Keyword(s):  
Virulence Genes ◽  
Yersinia Pseudotuberculosis ◽  
Bovine Mastitis ◽  
Raw Milk ◽  
Subclinical Mastitis ◽  
Biochemical Tests ◽  
Safety Hazard ◽  
Milk Samples ◽  
Antibacterial Susceptibility ◽  
Potential Food

This paper describes the first confirmed case of a subclinical mastitis caused by Yersinia pseudotuberculosis in a dairy cow from Italy. Milk samples from an adult cow of the Bruna breed were analyzed accordingly to standard milk cultivation protocols. Bacteriological examinations allowed to isolate atypical Gram-negative rods identified as Y. pseudotuberculosis using biochemical tests. The isolate was subjected to Whole Genome Sequencing (WGS) and the species identification was confirmed using rMLST. Moreover, the virulence and antibacterial susceptibility of the isolate have been also determined. The most common virulence genes were screened through WGS, showing the presence of inv, ail, pil and HPI genes. No antibiotic resistance was found. Even though scarcely described as causal agent of subclinical mastitis, the detection of Y. pseudotubercolusosis suggests that this pathogen could be spread to humans through raw milk, representing a potential food safety hazard.

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