Postgraduate publication

Dr. Sabelo Magagula is currently busy with his MMed degree in Vet Herd Health (Bovine) and has recently published an article, in the Journal of Dairy Research, entitled: Biofilm expression and antimicrobial resistance patterns of Streptococcus uberis isolated from milk samples of dairy cows in South Africa.

Authors: Sabelo Magagula, Inge-Mariè Petzer, Ibukun Michael Famuyide and Joanne Karzis

Date published: 2023

Short abstract:
The research described in this Research Communication addresses the hypothesis that intra-mammary infections with Streptococcus uberis (S. uberis) are associated with biofilm forma-tion, which limits antibiotic efficacy. This retrospective study investigated biofilm expressionand antimicrobial resistance (AMR) patterns of 172 S. uberis infections. Isolates were recov-ered from milk samples of subclinical, clinical, and intramammary infection cases on 30 com-mercial dairy herds. We determined the presence and intensity of biofilm expression ofS. uberis isolates in vitro in three somatic cell count categories to recognise their AMR pat-terns. An automated minimum inhibitory concentration system with a commercially availablepanel of 23 antimicrobial agents evaluated AMR, while biofilm determination was conductedusing a microplate method. The study established that all the S. uberis isolates assessedexpressed biofilm with the following varying degrees of intensities: 30 (17.8%) strong, 59(34.9%) medium and 80 (47.3%) weak biofilms. The newly registered UBAC mastitis vaccinecontaining biofilm adhesion components may, therefore, be a viable option for proactive mas-titis management under field conditions. No differences were identified between biofilmintensity and the three somatic cell count groups. Most S. uberis isolates indicated a high-level sensitivity to the antimicrobial agents tested. Resistances were present in 8.7, 8.1 and7.0% cases to rifampin, minocycline and tetracycline, respectively. Multidrug resistance wasobserved in 6.4%, emphasising AMR to antibiotics used in human medicine only. The lowoverall resistance suggests that farmers adhere to the prudent use of antimicrobials in thedairy industry.
 

Link to article