Detection of Altered Pattern of Antibiogram and Biofilm Character in Staphylococcus aureus Isolated From Dairy Milk

Abstract

Photoperiod and shelter have direct or indirect effects on phenotypic traits expression in different fish species. The present study was, therefore, intended to explore whether these light and shelter could influence some phenotypic traits of African catfish larvae under laboratory condition. Newly hatched larvae were stocked in plastic aquaria (10L) at a rate of 5 individuals/L and reared for one month under four treatments such as 24h light (24L), 24 h dark (24D), 12h light and 12h dark with PVC (12DL_PVC), and 12h light and 12h dark without PVC (12DL) conditions. A total of 108 larvae were sampled for phenotypic traits analysis. The results revealed that complete darkness (24D) significantly improved the overall growth parameters (total length, standard length, caudal peduncle length, anal fin length, caudal fin length, total body depth, dorsal fin length, pre dorsal distance, pre anal distance, pre ventral distance, head width, head length, eye diameter, maxillary barbell length, inter orbital length, and specific growth rate) than all other treatments, while no significant variation was found among other treatments. Although shelter did not show any significant role in the overall growth, it significantly reduced the larval mortality than those reared without shelter. The survival rates were also significantly different among various light regimes in which the highest was found in 24D (86%) followed by 12DL_PVC (74%), 24L (71%), and 12DL (60%). The study also revealed that larvae reared in 24D exhibited maximum dark brown body colouration (63%), while in 24L showed maximum light brown colouration (96%). On the other hand, maximum larvae were appeared as medium brown color (76%) in tanks having PVC, whereas many of them were light brown (61%) in non-PVC tanks. Taken together, the study suggests that C. gariepinus larvae should be reared in completely dark condition to enhance their overall production.

Staphylococcus aureus and Dairy Udder

“…Staphylococcus aureus is a major causative agent of intramammary infections in dairy animals with potential virulence of surface components (adhesins, capsular polysaccharides, protein A), toxins, extracellular enzymes and coagulase [21]. About 74% quarter prevalence of S. aureus in bovine udder [22] with overall prevalence exceeding 61% in dairy animals [4]. A wide array of genotypic variations has been observed with great genetic diversity in the isolates of bovine as well as caprine origin.…”

“…Therefore, to take an accurate decision to control the mastitis depends on understanding of economic impact of mastitis [43,53]. Mastitis is among the main reason in cattle for the use of antibiotics and this exposure of animal to antibiotics is main reason behind the development of antibiotic resistant bacteria and antimicrobial residues in milk which are of a great public health concern [4,7].…”

“…Staphylococcus aureus has a variety of strains, most notably multi-drug resistance and biofilm formation. The latter has received a lot of attention due to its ability to minimize the effects of antibiotics, colonize the mucous membrane of the epithelium, last longer, avoid immune reactions, and contribute to etiology [4]. Methicillin resistant S. aureus strains have been designated as emerging pathogen in livestock and dairy animals.…”

Etiology of Bovine Mastitis

“…So, the disease is also very important from the consumer's health risk point of view [6]. The presence of heat-resistant pathogenic spores and toxins in commercially available raw milk poses a serious threat to consumer's health and wellbeing [7][8][9].…”

“…Prior to the implementation of mastitis control strategies such as 5-point mastitis control program and later on 10-point mastitis control program by National Mastitis council, contagious mastitis pathogens were considered as the main causative agents of mastitis in dairy cows, even in developed countries [14][15][16]. The epidemiological field study of mastitis concluded that agents such as Staphylococcus aureus, Streptococcus agalactiae and Escherichia coli account for over 75% of mastitis cases, and Staphylococcus aureus is the most prevalent, resistant and challenging candidate among them [8,15,17]. The bacterial entry into mammary glands leads to bacteria interaction with the mammary epithelial cells, resulting in local inflammatory signs and deteriorated milk quality.…”