In this study, the production rate of both water-insoluble EPS, bacterial cellulose, and water-soluble EPS, P, was improved through сultivation of their producers on a nutrient media containing industrial wastes, and their material properties were analyzed. The growth rate and productivity of Gluconoacetobacter xylinus C3 strain on media with industrial wastes was investigated. An optimal nutrient medium based on molasses was selected for the bacterial cellulose producer. The nutrient medium contains 2% molasses, 1% yeast extract and peptone in a 1: 1 ratio, 0.3% sodium hydrogen phosphate, 0.1% citric acid and 1% ethanol. Cultivation of Gluconoacetobacter xylinus C3 strain on this medium for 7 days at 25–30 °С ensures its high productivity – 8.21 g/L. The composition of the optimized medium with molasses provides high mechanical properties (tensile strength – 37.12 MPa and relative elongation at break – 3.28%) of bacterial cellulose and does not affect the polymer microfibrillar structure. A modified Czapek-Dox medium with 10% molasses and 1% peptone is preferable for the exopolysaccharide accumulation by A. pullulans C8 strain. The optimized media has an advantage over the traditionally used media in terms of the efficiency of exopolysaccharide accumulation and cost reduction. The pullulan yield in media was 10.08 g/l, that is 1.5 times higher than in a standard Czapek-Dox medium. The surface morphology and microstructure of the pullulan samples obtained on different media showed minor changes. Therefore, the replacement of carbon source for molasses in a Czapek-Dox media for pullulan production did not alter the polymer content and viscosity.

Aeromonas spp. are opportunistic pathogens that are widely distributed in water sources, with several species being associated with fish and human diseases. We have previously identified an Aeromonas AB005 isolate from diseased Acipencer baerii. This isolate was identified as A. hydrophila based on the 16S rRNA and gyrB gene sequences. However, this novel strain does not produce indole and tested negative for ornithine decarboxylase and d-xylose fermentation—differences that set it apart from typical A. hydrophila strains. In the present study, this strain was subjected to whole-genome sequencing and compared with the genomes of the type strain (Aeromonas hydrophila ATCC 7966^T) and other Aeromonas spp. Comprehensive genome analysis suggests that AB005 represents a distinct species within the genus. The draft genome of the AB005 strain comprises 4,780,815 base pairs with a GC content of 61.2% and contains 6104 predicted protein-coding sequences along with numerous genes implicated in antibiotic resistance. The core/pan-genome analysis reveals extensive genetic diversity, indicative of a dynamic genomic structure. These findings collectively underscore the taxonomic distinction of the AB005 strain as a novel species and highlight its potential pathogenic implications in aquaculture and public health settings.

Ticks are involved in the circulation of a number of human pathogens, including spotted fever group (SFG) Rickettsia spp. and Coxiella burnetii. Little is known about the occurrence of these microorganisms in the southern region of Kazakhstan. In 2018-2022, a total of 726 ticks were collected from bitten humans, livestock, and vegetation in four oblasts of the southern region of Kazakhstan and subjected to DNA extraction. The overall infection rate of Coxiella spp. and Rickettsia spp. in the ticks was 3.3% (24/726) and 69.9% (300/429), respectively. Phylogenetic analysis of ompA and gltA genes revealed the presence of three pathogenic SFG rickettsiae: Candidatus R. tarasevichiae, R. aeschlimannii and R. raoultii in ticks collected from bitten humans. In addition, Candidatus R. barbariae was detected in six Rhipicephalus turanicus ticks for the first time in Kazakhstan. To determine the seroprevalence of C. burnetii infection, we performed a serological analysis of samples collected from 656 domestic ruminants (cattle, sheep, and goats) in the region. Overall, 23.5% (154/656) of the animals tested were positive for IgG against C. burnetii. Seroprevalence at the herd level was 54% (28/52). Goats (43%; 12/28; odds ratio (OD) = 28.9, p < 0.05) and sheep (31.9%; 137/430; OD = 18.1, p < 0.05) had higher seroprevalence than cattle (2.5%; 5/198). Among the risk factors considered in this study, age (p = 0.003) and the oblast in which the animals were sampled (p = 0.049) were statistically associated with seropostivity for Q fever in sheep, according to the results of multivariate logistic regression analysis. Seroprevalence ranged from 0% to 55.5% in animals in different districts of the southern region of Kazakhstan. Active C. burnetii bacteremia was detected in four of 154 (2.6%) seropositive animals. The data obtained provide strong evidence of the presence of pathogenic rickettsiae and C. burnetii in the southern region of Kazakhstan and emphasize the need to improve epidemiological surveillance in the region.

Bovine leukemia virus (BLV) remains a major concern for cattle industries worldwide due to its persistent nature, economic impact, and challenges in control. In this study, we conducted a comprehensive nationwide survey of BLV in Kazakhstan between 2014 and 2024, utilizing serological diagnostics to assess prevalence and characterize viral genotypes (2024). A total of 433,537 serum samples were screened by agar gel immunodiffusion (AGID), revealing an overall seroprevalence of 5.87%, with the highest rates observed in the North Kazakhstan, Kostanay, and East Kazakhstan regions. In 2024, a targeted analysis of 3736 serum and 536 whole blood samples across 17 regions was performed using AGID, ELISA, real-time PCR, and nested PCR. ELISA demonstrated higher sensitivity than AGID (10.4% vs. 8.2%), confirmed by statistical correlation (r = 0.97, p < 0.001) and a Wilcoxon signed-rank test (p = 0.026). Real-time PCR detected BLV DNA in 4.7% of samples, with the highest positivity in the East Kazakhstan and Abai regions, confirming active viral circulation. Validation of a domestically developed AGID diagnostic kit showed full concordance with commercial assays (IDEXX, IDvet), supporting its use in national surveillance programs. These findings highlight the endemic status of BLV in Kazakhstan. Molecular analysis of sequenced isolates revealed the presence of genotype G-7, consistent with strains circulating in neighboring countries. Together, these results underscore the importance of integrated serological and molecular approaches for effective monitoring and control.

Q fever (coxiellosis) is a zoonotic infection caused by the bacterium Coxiella (C.) burnetii that can infect many species of mammals, including humans. This work was aimed at studying the prevalence of C. burnetii among livestock and people in the southern region of Kazakhstan using enzyme-linked immunosorbent assay (ELISA). For serological monitoring, serum samples were collected from 100 residents of the Zhambyl oblast in the epidemiological season of 2021. It was found that the total seroprevalence of IgG to C. burnetii is 3.3%. A serological analysis of 282 blood serum samples from Capra hircus, Ovis aries and Bos taurus collected in the Turkestan and Zhambyl oblasts demonstrated that the total seroprevalence of antibodies to C. burnetii in livestock is 32.2% and 23.0% in the Turkestan and Zhambyl oblasts, respectively. An epidemiological analysis of livestock seromonitoring data was carried out. It was shown that the species belonging to Capra hircus, female sex and habitat in Baidibek, Sairam, Kazygurt districts of the Turkestan oblast and in T. Ryskulov of the Zhambyl oblast are risk factors for C. burnetii infection in the southern region of Kazakhstan. The results indicate the need for further research in this direction to isolate the pathogen and identify its main reservoirs. Key words: Coxiella (C.) burnetii, coxiellosis, epidemiology, enzyme immunoassay, serum.