Antibiotic susceptibility of Staphylococcus aureus isolated from subclinical bovine mastitis cases and in vitro efficacy of bacteriophage

Abstract

Staphylococcus aureus is an opportunistic pathogen that may cause severe infections in livestock, and represents the major cause of mastitis in dairy cows. Currently, instead of using antibiotics, new strategies are sought to reduce this clinical health problem. The aim of this study was to determine the efficacy of phage therapy to kill S. aureus strains obtained from farms located at the State of Guanajuato, México. Thirty-six S. aureus strains from cow milk with subclinical mastitis were isolated and identified, and the susceptibility to antibiotics and four phages also isolated in this work was tested. It was found that more of 90% of S. aureus isolates were not susceptible to six or more antibiotics, and 100% were resistant to penicillin, dicloxacillin, cefotaxime, ampicillin and cephalothin, and 81 and 77%, to tetracycline and cefuroxime, respectively. Fortunately, 100% of S. aureus isolates were susceptible to phages used in this work, which was detected as clear zones using specific phage. It was shown for the first time, that phages used in this study are active against pathogenic S. aureus and might be incorporated into the therapy as an important tool for the control of staphylococcal bovine mastitis, specially to antibiotic-resistant S. aureus strains isolated in farm located at the state of Guanajuato, México; and its use might be extended to other regions inside or outside the country.

Bovine mastitis: risk factors, therapeutic strategies, and alternative treatments — A review

“…Bacteriophage are viruses that specifically infect bacteria and are harmless to humans, animals, and plants; thus, bacteriophage and their derivatives (i.e., endolysin, exolysin, and depolymerase) are being deemed as valuable antimicrobial alternatives with a potential to reduce the current use of antibiotics in agri-food production, increasing animal productivity and providing environmental protection [118]. Varela-Ortiz et al [119] isolated 4 phage lysates from an apathogenic Staph. aureus strain and tested on 36 Staph.…”

Analysis of virulence traits of Staphylococcus aureus isolated from bovine mastitis in semi-intensive and family dairy farms

“…Ochoa-Zarzosa et al [ 12 ] reported 100% resistance to PE class antibiotics, but low levels of resistance to other antibiotics such as TE and PEF. In 2018, a study carried out in Guanajuato state reported high rates of resistance to β-lactam antibiotics and to PEF, SXT, and E (48%–58%) [ 17 ]. Importantly, Mexican farmers commonly treat animals without any previous knowledge of antimicrobial susceptibility, and such practices undoubtedly influence pathogen transmission and resistance and have epidemiological impacts quite different from those of large-scale dairy farms [ 17 ].…”

Comparison of MALDI-TOF mass spectrometry with phenotypic methods for identification and characterization of Staphylococcus aureus causing mastitis

“…Mastitis is one of the common obstacles in various dairy farms in many parts of the world from the investigative, pathogenic, cost-effective, and public health-related viewpoints (Varela-Ortiz et al, 2018). Mastitis has severe economic effects and leads to a decrease in the quality and quantity of milk due to the change in milk composition; the milk volume becomes instable.…”

“…They include Escherichia coli and Streptococcus agalactiae. However, Staphylococci remain the key factor that causes mastitis in a lot of dairy herds (Sender et al, 2017;Varela-Ortiz et al, 2018).…”