Epidemiology and molecular characterization of Staphylococcus aureus causing bovine mastitis in water buffaloes from the Hazara division of Khyber Pakhtunkhwa, Pakistan

Abstract

Buffalo represent a major source of milk in Pakistan. However, production is impacted by the disease bovine mastitis. Mastitis causes significant economic losses, with Staphylococcus aureus (S. aureus) being one of its major causative agents. While much work has been done understanding the epidemiology of bovine mastitis in Pakistan, detailed molecular characterization of the associated S. aureus is unavailable. In the current study both the epidemiological and molecular characterization of S. aureus from bovine mastitis in the Hazara division of Pakistan are examined. S. aureus was isolated from 18.41% of the animals, and left quarters more prone to infection (69.6%) than right quarters (30.4%). Sub-clinical mastitis (75.31%) was more prevalent than clinical mastitis (24.69%), with infections evenly distributed amongst the eight districts. Molecular characterization revealed that only 19.6% of the isolates were methicillin-resistant, and four strains types identified, including ST9-t7867-MSSA, ST9-MSSA, ST101-t2078-MSSA, and ST22-t8934-MRSA-IVa. Antiseptic resistance genes were not detected in the isolates, and low levels of antibiotic resistance were also noted, however the methicillin-resistant strains had higher overall antibiotic resistance. This study represents the most complete molecular typing data for S. aureus causing bovine mastitis in the Hazara district of Pakistan, and the country as a whole.

Molecular characteristics of Staphylococcus aureus strains isolated from subclinical mastitis of water buffaloes in Guangdong Province, China

“…Similar results were observed in S. aureus isolates from dairy cows with mastitis in northern China (31). However, other researchers reported lower rates of antimicrobial resistance in S. aureus isolates in Pakistan (13). Cephalosporins are important antimicrobial agents, and S. aureus isolates resistant to ceftiofur have been reported (23).…”

“…MRSA is a global health concern since it is not only resistant to β-lactams but also nonsusceptible to other commonly used antimicrobial agents (36). In the Philippines and Pakistan, the MRSA prevalence was 25.81 and 19.6%, respectively, in water buffaloes with mastitis (13,37), while a much lower rate (2.2%) of MRSA was detected in water buffaloes with mastitis in Iran (38). Several factors, such as age, feeding status, body conditions, and hand or machine hygiene on the farm, may contribute to this phenomenon.…”

“…In clinical mastitis, clots and flakes can be observed in milk, and the quarters become swollen with severe conditions leading to the formation of lacerations, necrosis and cord formation of the teat. While no clinical signs or symptoms can be seen in subclinical mastitis, there is a reduction in milk production and deterioration of milk quality (13). Subclinical infection is 15-40 times more prevalent than clinical infection and can rapidly spread on a farm (14).…”

Cell membrane-coated nanoparticles: An emerging antibacterial platform for pathogens of food animals

“…Molecular typing of S. aureus indicated that certain animal lineages are specific to host while some are able to colonize or infect a wide variety of animals ( 133 ). The most notable case is ST398, which was primarily detected among pigs, and afterwards was found in various food-chain animals as well as in humans.…”

Virulence and resistance profiling of Staphylococcus aureus isolated from subclinical bovine mastitis in the Pakistani Pothohar region

“…Prevalence of Staphylococcus aureus -associated mastitis was found to be 32%, 27%, 23%, 51%, 13%, 31%, and 41% from Africa, Asia, Europe, Latin America, North America, Oceania, and India, respectively. In Pakistan, different studies report the overall mastitis prevalence rates, ranging from 42 to 70% 4 – 7 . While mastitis in cattle causes major productivity losses, subclinical mastitis is considered a major threat due to the absence of any visible symptoms.…”