![]() ![]() Therefore, the dependency of dairy farms on antimicrobial agents is a commonly widespread phenomenon resulting in many serious problems concerned with the causative agents’ pathogenicity and public health. ![]() Nowadays, antimicrobial agents are widely used to prevent and control mastitis and other diseases affecting dairy herds. Identification and isolation of various pathogens causing mastitis enable appropriate choices for antimicrobial therapy and proper preventive mastitis management. coli non -aureus staphylococci (NAS) Streptococcus spp., especially S. However, significant pathogens associated with SCM are E. Mastitis could be caused by more than 135 types of microbial pathogens. Īdditionally, sub-clinically mastitic cows should be regarded as a risk for disseminating mastitis pathogens within and between dairy herds. It is worth mentioning that SCM causes more than 3–4 times economic losses as compared to CM, and milk production decreases by 17.2% in SCM without the occurrence of any obvious clinical signs. Subclinical mastitis (SCM) is an asymptomatic disease characterized by increased milk somatic cell count and can only be diagnosed by laboratory tools using special tests such as the California mastitis test (CMT), Whiteside test, Somatic cell count (SCC) and Electrical conductivity test. Clinical mastitis is recognized by physical, chemical and microbiological alteration found in milk, such as changes in color and consistency of the udder, alteration in milk contents and presence of pathogenic microorganisms. Mastitis is divided into two main types, clinical (CM) and subclinical (SCM). In the USA alone, mastitis causes annual losses in the dairy industry, reaching 1.7 billion US dollars a year. Mastitis is caused by multi-etiological agents, including various environmental and microbial predisposing factors. Herd health improvement interventions are required to protect human health and society.īovine mastitis is a significant challenge globally threatening the dairy industry, affecting both the quantity and quality of milk and resulting in substantial economic losses. The coexistence of pathogenic bacteria in milk is alarming, threatens human health and has a public health significance. The presence of a high prevalence of SCM in dairy animals impacts milk production and milk quality. A significant association between the phenotypes and genotypes of AMR in different bacteria was recorded. The fimH and tsh genes were found in 80% and 60%, respectively. coli isolates harbored tetA gene conferring resistance to tetracycline and sul1 gene conferring resistance to sulfonamides. Meanwhile 73.3% of streptococci isolates harbored aph(3’)-IIIa gene conferring resistance to aminoglycosides and cfb gene. aureus isolates and in 26.7% and 53.3% of NAS, respectively. Implementation of PCR revealed the presence of mecA and blaZ genes in 60% and 46.7% of S. Antimicrobial susceptibility testing of isolates revealed a high degree of resistance to the most commonly used antimicrobial compound in human and veterinary medicine. coli (49.8%), Staphylococcus aureus (44.9%), streptococci (44.1%) and non- aureus staphylococci (NAS) (37.1%). The most frequent bacterial isolates were E. Bacteriological examination of CMT positive quarters revealed that the prevalence of bacterial isolation in subclinically mastitic quarters was 90.4% (26 and 64.3% had single and mixed isolates, respectively). The total prevalence of SCM was 46% and 44.8% based on California Mastitis Test (CMT) and Somatic Cell Count (SCC), respectively. One thousand sixty-quarter milk samples (QMS) were collected aseptically from 270 apparently healthy cows in three farms and examined. ![]() The antimicrobial resistance profiles and specific virulence-associated genes causing bovine SCM were investigated. The current study aimed to investigate the prevalence and major bacterial pathogens causing subclinical mastitis (SCM) in three bovine dairy herds, with a history of SCM, at three Governorates in North Upper Egypt. Mastitis is a significant disease affecting dairy cattle farms in Egypt. ![]()
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