scholarly journals The Genetic Relatedness and Antimicrobial Resistance Patterns of Mastitis-Causing Staphylococcus aureus Strains Isolated from New Zealand Dairy Cattle

2021 ◽  
Vol 8 (11) ◽  
pp. 287
Author(s):  
Sabrina S. Greening ◽  
Ji Zhang ◽  
Anne C. Midwinter ◽  
David A. Wilkinson ◽  
Scott McDougall ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
New Zealand ◽  
Antimicrobial Resistance ◽  
Genetic Relatedness ◽  
Bovine Mastitis ◽  
Subclinical Mastitis ◽  
Antimicrobial Usage ◽  
Dry Cow Therapy ◽  
Usage Patterns ◽  
Resistance Patterns

Staphylococcus aureus is one of the leading causes of bovine mastitis worldwide and is a common indication for use of antimicrobials on dairy farms. This study aims to investigate the association between on-farm antimicrobial usage and the antimicrobial resistance (AMR) profiles of mastitis-causing S. aureus. Whole-genome sequencing was performed on 57 S. aureus isolates derived from cows with either clinical or subclinical mastitis from 17 dairy herds in New Zealand. The genetic relatedness between isolates was examined using the core single nucleotide polymorphism alignment whilst AMR and virulence genes were identified in-silico. The association between gene presence-absence and sequence type (ST), antimicrobial susceptibility and dry cow therapy treatment was investigated using Scoary. Altogether, eight STs were identified with 61.4% (35/57) belonging to ST-1. Furthermore, 14 AMR-associated genes and 76 virulence-associated genes were identified, with little genetic diversity between isolates belonging to the same ST. Several genes including merR1 which is thought to play a role in ciprofloxacin-resistance were found to be significantly overrepresented in isolates sampled from herds using ampicillin/cloxacillin dry cow therapy. Overall, the presence of resistance genes remains low and current antimicrobial usage patterns do not appear to be driving AMR in S. aureus associated with bovine mastitis.

scholarly journals Diversities of antimicrobial resistance patterns across Staphylococcus aureus and Coagulase-Negative Staphylococci isolated from dairy herbs in Jiangsu province, China

2020 ◽  
Author(s):  
Weijie Jin ◽  
Weidong Lin ◽  
Qing Feng ◽  
Dashuai Zhang ◽  
Juan Yang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Subclinical Mastitis ◽  
Jiangsu Province ◽  
The Other ◽  
Multiple Drug ◽  
Drug Resistant ◽  
Coagulase Negative Staphylococci ◽  
Resistance Patterns

Abstract Background As mastitis major causing agents, Coagulase-Negative Staphylococci (CNS) and Staphylococcus aureus (SA), are important and their connections are special and worth comparing. The overall aim of this study is to investigate antimicrobial resistance patterns of CNS and SA. Understanding the special characters of staphylococci is essential for finding the precise strategies or directions against them. Results Staphylococci (47.63%) were the commonest pathogens in subclinical mastitis in Jiangsu province. 73.34% and 45.78% of CNS respectively were extensively drug-resistant (XDR) strains and multiple drug-resistant (MDR) strains, mainly resisting penicillin (77.78%) and ceftazidime (55.95%); for SA, 62.52% of them were MDR strains and resistant to penicillin (94.05%) and norfloxacin (58.33%). Notably, 4 CNS were pandrug-resistant (PDR) strains. According to the chi-square test results, we summary and find that SA was more resistant to quinolones (ciprofloxacin, levofloxacin, and norfloxacin) and co-trimoxazole antibiotics than CNS, significantly; on the other hand, CNS were significantly more resistant to lincomycins (clindamycin), macrolides (including erythromycin and clarithromycin), tetracycline, and nitrofurantoin antibiotics than SA,, in total. Resistance genes were detected more frequently in CNS than SA; nearly a third of CNS resit penicillin by β-lactamase coded by blaZ and CNS resist tetracycline mainly by protein pump mechanism. For SA, blaZ was detected out 27.2%, and the other five resistance genes were rare to be found. Conclusion Responding to antibiotics interfering with metabolisms of nucleotide, SA might be more resistant than CNS; while CNS strains are more likely to become mutations to survive under the stress of antibiotics interfering with protein synthesis. These might provide the advantages for CNS to represent like a reservoir of resistance genes for other staphylococci as the previous researches’ assumption.

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 Biofilm-Forming Potential of Staphylococcus aureus Isolated from Bovine Mastitis in New Zealand

2018 ◽  
Vol 5 (1) ◽  
pp. 8 ◽  
Author(s):  
Shirli Notcovich ◽  
Gina DeNicolo ◽  
Steve Flint ◽  
Norman Williamson ◽  
Kristene Gedye ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
New Zealand ◽  
Bovine Mastitis

scholarly journals Expression of icaA and icaD genes in biofilm formation in Staphylococcus aureus isolates from bovine subclinical mastitis

2021 ◽  
Vol 41 ◽  
Author(s):  
Viviane F. Marques ◽  
Huarrisson A. Santos ◽  
Thomas H. Santos ◽  
Dayanne A. Melo ◽  
Shana M.O. Coelho ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Phenotypic Expression ◽  
Bovine Mastitis ◽  
Subclinical Mastitis ◽  
Transcriptional Analysis ◽  
Important Species ◽  
High Prevalence ◽  
Staphylococcus Spp

ABSTRACT: Staphylococcus spp. plays a significant role in the etiology of bovine mastitis. Staphylococcus aureus is considered the most important species due to the high prevalence and the difficulty of in vivo treatment that is related to the expression of virulence factors and biofilm formation. This study aimed to detect the phenotypic expression of the biofilm formation in 20 S. aureus isolated from bovine mastitis and to evaluate the expression and regulation of genes involved in its production. MALDI-TOF and phenogenotypic identification assays were performed to characterize the isolates. The phenotypic biofilm production and the presence of icaA and icaD and bap genes were evaluated. The Agr system was typified (agr I, agr II, agr III and agr IV) and its regulator (agr RNAIII) was detected. Furtherly, Real-time PCR (qPCR) was performed at chosen times to quantify the expression of icaA, icaD and hld genes in three selected isolates. All 20 strains were biofilm producers and most presented icaA and icaD genes. Only one isolate presented the bap gene. The agr gene type II showed a prevalence of 70%. Transcriptional analysis revealed increased expression of ica genes at eight hours of growth. These results confirm that polysaccharides production mediated by the icaADBC operon genes is an essential mechanism to the biofilm formation and contributes to the early stages of bacterial growth.

scholarly journals Within-Host Adaptation of Staphylococcus aureus in a Bovine Mastitis Infection Is Associated with Increased Cytotoxicity

2021 ◽  
Vol 22 (16) ◽  
pp. 8840
Author(s):  
Katharina Mayer ◽  
Martin Kucklick ◽  
Helene Marbach ◽  
Monika Ehling-Schulz ◽  
Susanne Engelmann ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bovine Mastitis ◽  
Adaptive Strategy ◽  
Subclinical Mastitis ◽  
Growth Conditions ◽  
Typical Feature ◽  
Host Adaptation ◽  
Bovine Mammary Epithelial Cells ◽  
Strain Pair

Within-host adaptation is a typical feature of chronic, persistent Staphylococcus aureus infections. Research projects addressing adaptive changes due to bacterial in-host evolution increase our understanding of the pathogen’s strategies to survive and persist for a long time in various hosts such as human and bovine. In this study, we investigated the adaptive processes of S. aureus during chronic, persistent bovine mastitis using a previously isolated isogenic strain pair from a dairy cow with chronic, subclinical mastitis, in which the last variant (host-adapted, Sigma factor SigB-deficient) quickly replaced the initial, dominant variant. The strain pair was cultivated under specific in vitro infection-relevant growth-limiting conditions (iron-depleted RPMI under oxygen limitation). We used a combinatory approach of surfaceomics, molecular spectroscopic fingerprinting and in vitro phenotypic assays. Cellular cytotoxicity assays using red blood cells and bovine mammary epithelial cells (MAC-T) revealed changes towards a more cytotoxic phenotype in the host-adapted isolate with an increased alpha-hemolysin (α-toxin) secretion, suggesting an improved capacity to penetrate and disseminate the udder tissue. Our results foster the hypothesis that within-host evolved SigB-deficiency favours extracellular persistence in S. aureus infections. Here, we provide new insights into one possible adaptive strategy employed by S. aureus during chronic, bovine mastitis, and we emphasise the need to analyse genotype–phenotype associations under different infection-relevant growth conditions.

scholarly journals Characterization of Staphylococcus aureus Isolates From Cases of Clinical Bovine Mastitis on Large-Scale Chinese Dairy Farms

2020 ◽  
Vol 7 ◽  
Author(s):  
Kangjun Liu ◽  
Luyao Tao ◽  
Jianji Li ◽  
Li Fang ◽  
Luying Cui ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cluster Analysis ◽  
Antimicrobial Resistance ◽  
Large Scale ◽  
Bovine Mastitis ◽  
Dairy Farms ◽  
Clinical Mastitis ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms

Bovine mastitis is a prevalent disease that causes serious economic problems globally in the dairy industry. Staphylococcus aureus is an important pathogen of bovine mastitis. This study was conducted to characterize S. aureus isolates from clinical bovine mastitis cases in large-scale dairy herds in China. S. aureus was isolated from 624 clinical mastitis cases and confirmed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). In total, 62 S. aureus isolates were obtained. Cluster analysis, genetic diversity, quantification of biofilm formation, antimicrobial resistance, and detection of virulence genes were performed on these isolates of S. aureus. Eight isolates harbored the mecA gene and were sensitive to oxacillin. MALDI-TOF MS cluster analysis revealed that the 62 isolates were divided into three major clusters (I, II, III) and eight main groups (A–H) at the distance level of 700. The agr II was the most prevalent (56.5%). The 62 S. aureus isolates were assigned to seven spa types. The most common spa type was t529(58.1%), followed by t2196 (14.5%), t518 (14.5%), t571(6.5%), t034 (3.2%), t2734 (1.6%), and t730 (1.6%). Five STs were identified from seven representative isolates as follows: ST630/CC8, ST97/CC97, ST50, ST398, and ST705. All isolates had the ability to form biofilm. Antimicrobial resistance was most frequently observed to ciprofloxacin (29%), followed by penicillin (24.2%), and streptomycin (9.6%). All isolates harbored the fnbA, clfB (100%), icaA, and icaD genes. This study provides the basis for the development of bovine mastitis prevention program on large-scale dairy farms.

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