Farming Practices Influence Antibiotic Resistance and Biogenic Amine Capacity of Staphylococci from Bulk Tank Ewe’s Milk

Abstract

Staphylococci are one of the main microorganisms responsible for intramammary infections in sheep, causing important economic losses for farmers and eventually health problems in humans, especially by the consumption of dairy products made with raw milk containing toxic compounds, such as biogenic amines or antibiotic resistant bacteria. This study aimed to check the presence and safety of staphylococci in bulk tank ewe’s milk from different farms, and to determine the relationship between the presence of these staphylococci and farming practices, by applying nonlinear canonical correlation models (OVERALS). Two-hundred and fifty-nine staphylococci from milk samples from eighteen farms were genotyped and representative isolates of the major clusters were identified as belonging to Staphylococcus (S.) aureus, S. epidermidis, S. arlettae, S. lentus, S. simulans, and S. chromogenes species. Identified isolates were assayed in terms of their safety, by evaluating resistance to antimicrobial drugs and the aminobiogenic capacity, using both phenotypic and genetic assays. Antibiotic resistance phenotypic assay revealed that 82.9% were resistant to some antibiotics, although in the genotypic assay only the genes tetM, ermB, ermC, and grlA were detected. Fifty-three percent were high biogenic amine (BA) producers, being putrescine the most produced amine. A lowered risk of finding antibiotic-resistant and BA-producing staphylococci is related to some farming methods such as enrolling in a breeding program, use of good farming practices, postdipping teat disinfection, hygienic livestock housing, or periodic check of the milking machine.

The effect of Lactococcus lactis and Bifidobacterium bifidum probiotics cell free supernatants on the expression of HDC and TDC genes in Staphylococcus strains isolated from milk

“…The difference among Staphylococcus isolates in terms of amino acid decarboxylase activity is in accordance with previous studies (Anderegg et al, 2020;Sang et al, 2020) which reported that the production of biogenic amines could vary significantly at the isolate level. Our data confirmed that the production of biogenic amine is an isolated specific trait as reported earlier (Jeong et al, 2014;Poveda et al, 2020). A wide range of data has been reported on the production of biogenic amines by staphylococcal isolates.…”

“…Thus, it is necessary to monitor the biogenic amines in raw and processed milk due to their toxicity and usefulness as milk spoilage index. Bacterial decreasing methods for milk, such as high pressure, irradiation, pasteurization, or homogenization, diminish the levels of biogenic amine producing bacteria; however, there is evidence concerning contamination and production of biogenic amines in raw and processed milks (Gavina Manca et al, 2020;Poveda et al, 2020;Pivetta et al, 2020;Mousavi Khaneghah et al, 2020). In this study, in light of previous data supporting probiotics advantages, we examined the effects of L. lactis and B. bifidum (two probiotic bacteria) on the HDC and TDC genes of Staphylococcus species isolated from raw milk.…”

“…Similarly, in the present study, a significant percentage of the samples contained bacteria that produced biogenic amines, generating different percentages of histamine and tyramine in the milk. Some studies have confirmed that the production of biogenic amines is not associated with the presence of a specific amino acid decarboxylase gene (Jeong et al, 2014); others have reported that the lack of correlation between the presence of genetic determinants and production of biogenic amines is attributed to the use of non-staphylococcal species primer in PCR (Poveda et al, 2020). Our study revealed a linear correlation between the existence of TDC and HDC genes and production of target biogenic amines, which could be due to the staphylococcal specific primers used in PCR reaction.…”

“…Biogenic amines are very harmful products of milk-contaminating microorganisms. These amines are low molecular weight compounds mainly formed by the decarboxylation of amino acids or amines and transfer of aldehydes and ketones (Poveda et al, 2020). These amines are synthesized by microbial, plant, and animal metabolism.…”

Will Fly Repellency Using Deltamethrin Reduce Intramammary Infections, Stress and Fatigue Indicators of Dairy Ewes under Intensive Management?

“…Moreover, IMIs have been identified as important causes of (i) welfare concerns in ewes [ 4 ]; and (ii) public skepticism regarding the safety and quality of milk and the products thereof [ 2 ]. The zoonotic potential of specific pathogens, antibacterial resistance due to the extensive use of antibiotics for the treatment of IMIs, and antibiotic residues in milk and meat, have emerged as public health hazards [ 5 , 6 ]. Nowadays, the existed legal and regulatory framework has not substantially described a comprehensive mitigation strategy against IMIs at the farm level in dairy ewes; instead, the extrapolation of data from dairy cattle is the norm, since studies to assess possible risk factors in dairy sheep are scarce.…”