Antimicrobial and Antibacterial Agents

Algeria is a country traditionally a consumer of fermented milk products, which until recently was manufactured in rural areas, mainly for self-consumption, by spontaneous fermentation of locally produced raw milk. On the one hand, non-compliance with good hygiene practices during milking, makes these products in several cases causing food poisoning; on the other hand the increased use of antibiotics for the treatment of dairy cows has contributed to the growing emergence of antibiotic-resistant bacterial strains. The development of natural control means with respect to thèse multi résistant Stains is Born as the use of lactic bacteria endowed with antibacterial activity. In this context, isolation of strains of S. aureus is made from 60 samples of artisanal fermented milk type Ben harvested from 20 farms in the wilaya of Bejaia. Phenotypic and biochemical identification was performed. In order to select strains of antibiotic-resistant S. aureus, an antibiotic susceptibility test was performed for cefotaxime and ceftazidime followed by an analysis of resistance phenotypes. 10 strains of Lactococcus were tested against strains of S. aureus resistant via the spot test. In order to determine the probable origin of the antibacterial activity of these strains, a test of the wells is carried out for the supernatants of lactic strains. The results obtained show that 50% of the ben samples are contaminated with S. aureus, in fact, 60 S.aureus strains are identified. The study of the sensitivity of these strains with respect to cefotaxime and ceftazidime made it possible to select 20 strains of S. aureus with a 32.62% strength of resistance. The analysis of the resistance phenotypes revealed the production of CTX-M-15 β-lactamases in 10 strains. The study of the antibacterial activity revealed zones of inhibition which vary between 15 and 35 mm. However, the well test showed that six strains of Lactococcus showed inhibitory zones that exceeded 15mm after pH neutralization of the supernatant. In conclusion., This high rate of resistance seems to reflect the inappropriate use of antibiotics. Nevertheless, the use of lactic bacteria strains of the Lactoccocus genus endowed with antibacterial activity could be an alternative for having artisanal products based on healthy raw milks.