Contamination of Kazakhstan cheeses originating from and its resistance to antimicrobial drugs.

Background And Aim: , a commensal intestine bacterium of vertebrates, is widely distributed in the environment and indicates the microbiological quality of food products in relation to coliforms. In addition, virulent strains, particularly O157:H7, cause outbreaks of toxic infections caused by consuming dairy products. Because food safety studies regarding have not been conducted in Central Asia, this research aimed to study the characteristics of contamination, microbiological and genotypic properties, and resistance to antimicrobial agents of strains that contaminate various types of commercialized cheeses originating from Kazakhstan.

Materials And Methods: In retail outlets, 207 samples of three types of cheese produced by 22 industrial and eight small enterprises in the central, eastern, southern, and northern regions of Kazakhstan were selected in 2020-2023. contamination was examined using standard microbiological, mass spectrometric, and molecular genetic methods. The discodiffuse European Committee on Antimicrobial Susceptibility Testing method was used to test the resistance of the identified isolates (65/207; 31.4%) to 20 antibacterial drugs. The Shiga toxin-producing () and O157:H7 () genes were investigated in all isolates using multiplex polymerase chain reaction.

Results: An average of 31.4% samples of commercial Kazakhstani cheeses of various types were found to be contaminated with . in almost all geographical regions of Kazakhstan, regardless of the productivity of the dairy enterprises. Soft cheeses produced by small farms (80% of samples) packaged at the retail site (100%) were the most contaminated with . . The microbiological index (colony-forming unit/g) was unsatisfactory and unsuitable in 6.2% of such cheese samples. For the first time in Central Asia, the enteropathogenic strain O157:H7 was detected in 0.5% of cheese samples. . isolates from cheese samples were resistant to 65% of antibacterial drugs and contained resistance genes to β-lactams, sulfonamides, and quinolones groups. At the same time, 25% of the . isolates were multi-resistant to three or more antimicrobial agents.

Conclusion: The high level of contamination caused by multi-antibiotic resistant strains, including pathogenic pathogens, poses a risk to public health and highlights the need for further research on the monitoring and control of coliform enteropathogens in food products.