RESUMO
Background and Aim: Escherichia coli, 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 E. coli O157:H7, cause outbreaks of toxic infections caused by consuming dairy products. Because food safety studies regarding E. coli 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 E. coli 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. E. coli 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 E. coli isolates (65/207; 31.4%) to 20 antibacterial drugs. The Shiga toxin-producing E. coli (VT1 and VT2) and E. coli O157:H7 (eae) genes were investigated in all E. coli 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 E. coli 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 E. coli. 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 E. coli O157:H7 was detected in 0.5% of cheese samples. E. coli isolates from cheese samples were resistant to 65% of antibacterial drugs and contained resistance genes to ß-lactams, sulfonamides, and quinolones groups. At the same time, 25% of the E. coli isolates were multi-resistant to three or more antimicrobial agents. Conclusion: The high level of contamination caused by multi-antibiotic resistant E. coli 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.
RESUMO
Background and Aim: Trichinellosis remains a dangerous disease for humans and animals, which can lead to a lethal outcome. The study of specific body reactions in response to invasion by different types of Trichinella can help in the early diagnosis of the disease. This study aimed to investigate the hematological, biochemical, and serological characteristics of rabbits experimentally infected with trichinellosis, as well as the possibility of using changes in these parameters at various disease stages for early hematological, biochemical, and serological diagnosis of trichinellosis. Materials and Methods: Three groups of rabbits were orally infected with Trichinella nativa and Trichinella spiralis derived from encysted T. spirtalis larvae in pork muscle samples. The first and second groups were infected with T. nativa and T. spiralis, respectively, while the third group served as control by receiving a physiological solution. An ADVIA 2120i automatic hematology analyzer with a blood smear staining module was used to determine the hematological parameters of rabbits. Antigens were used in an enzyme-linked immunosorbent assay (ELISA) to detect antibodies in the sera of infected rabbits that were supernatants containing excretory-secretory antigens (ES-Ag) and somatic antigen (S-Ag). Results: The detection of biochemical responses to the invasion of T. nativa and T. spiralis isolates was detected and hematological parameters were featured in two cases. Trichinella nativa increased the number of erythrocytes, neutrophils, eosinophils, monocytes, basophils, and thrombocytes on day 7 in rabbits. Creatine kinase (CK) is regarded as the most important indicator for the early detection of parasite invasion. Blood biochemistry showed no active response to T. spiralis infection. However, counts of erythrocytes, neutrophils, lymphocytes, and CK rose significantly. In both color indicators, the number of thrombocytes decreased. Enzyme-linked immunosorbent assay with ES-Ag and S-Ag of these isolates demonstrated the ability to detect antibodies as early as 7 days after infection, with a significant increase in the marker up to 70 days. Conclusion: On the 7th day after infection, blood tests of infected animals revealed CK-N-acetyl-cysteine (18.2%) and neutrophils (43%) when infected with T. nativa and neutrophils (26.7%) and lymphocytes (20%) when infected with T. spiralis. These indicators may serve as specific parameters for the early detection of Trichinella spp. invasion.
