The paper presents results of the Salmonella identifcation, testings of recovered isolates for their susceptibility to antibiotics and their serogroup and serovar distribution. In 2012–2017 13,774 tests of animal products were performed, 105 Salmonella contaminated samples were detected which is 0.76% of the total number of the tested samples. As a result, 31 isolates were recovered. It was established that 22 of them belonged to seven serovars: S. enteritidis, S. infantis, S. nigeria, S. montevideo, S. typhimurium, S. derby, S. meleagridis. S. infantis (38.7%) and S. enteritidis (16.1%) were identifed as the most spread serovars. There was observed a trend of increase in contaminated samples: 1.13% in 2012 upto 2.84% in 2017. The performed tests for antimicrobial resistance demonstrated that all isolates were susceptible to the following antibiotics: carbpenemes (meropenem, imipenem), β-lactams (amoxicillin /clavulanate), aminoglycoside (amikacin, gentamycine), macrolides (azithromycin). Most of the isolates demonstrated susceptibility to β-lactam antibiotics (ceftriaxone, cefotaxime), fluoroquinolones (ciprofloxacin) and aminoglycosides (kanamycin). Resistance at least to one antibiotic was detected in 12.9% (4/31) of isolates. Resistance to at least three antibiotics was detected in 6.5% (2/31) of isolates. 58.1% (18/31) of isolates demonstrated multiple resistance (to four or more antibiotics).
Bacteria of Campylobacter genus are ones of the main zoonotic pathogens causing human and animal diseases. Campylobacter organisms are microaerophiles and, therefore, require low oxygen concentration (3–5%) and high carbon dioxide concentration (3–10%) for their growth. They use amino acids rather than carbons as a source of energy. Classical bacteriological methods for Campylobacter spp. detection are not always successful due to diffi culties in creating optimal conditions for their growth. Therewith, development and implementation of molecular methods for Campylobacter detection and identifi cation are of current importance. Assay for qualitative Campylobacter spp. detection with real-time polymerase chain reaction using CFX-96 thermocycler was optimized. Highly specifi c segment of 16S rRNA gene allowing identifi cation of 6 Campylobacter species: C. jejuni, C. coli, C. lari, C. upsaliensis, C. helveticus и C. hyointestinalis was selected as an amplifi cation target. Optimal magnesium ion concentration (2.5 мМ) and primer annealing temperature (58 °С) were determined. Eighteen reference strains of various bacteria were tested. Only tests of Campylobacter genus strains gave positive results. The method sensitivity was 40 target molecules. The said method was used for testing 76 samples of raw materials of animal origin. Campylobacter spp. genome was detected in 18 samples. Obtained results showed that the optimized variant of real-time polymerase chain reaction based on 16S rRNA gene amplifi cation was a specifi c, sensitive, rapid, reproducible and accurate method for qualitative detection of Campylobacter spp. in samples of raw animal materials.
The study was aimed at Salmonella isolation from samples of animal food products submitted for testing from various regions of the Central part of the RF and serotyping of the recovered isolates and their testing for antibiotic resistance. A total of 2,342 tests were performed and 87 (3.7%) Salmonella isolates were recovered. Most of them (54 isolates) were recovered from poultry meat and poultry meat preparation samples submitted for testing. Besides, 25 isolates were recovered from pork and pork preparation samples, 7 isolates – from beef samples, 1 isolate – from hard cheese samples. Serotyping of 64 Salmonella isolates showed that the majority of the isolates (57.8%) belonged to О7 group. Also, Salmonella isolates belonging to О9 (21.9%), О8 (9.4%), О4,5 (6.2%) and О10 (4.7%) were detected in food products. S. Enteritidis, (23.3%), and S. infantis (18.7%), were predominant based on the number of detections. Also, the following serovars were identified: S. typhimurium, S. nigeria, S. montevideo, S. derby, S. meleagridis, S. virchov, S. oranienburg. Tests of 87 Salmonella isolates for their antibiotic resistance with disk diffusion method revealed that they were highly resistant to nalidixic acid (70.1%), tetracycline (49.4%), trimethoprim/sulfamethoxazol (40.2%). Moreover, nalidixic acid-resistance was common for all identified isolates. Seventeen isolates (19.5%) demonstrated multiple antibiotic resistance and two isolates were found to be resistant to ≥7 antibiotics. All recovered isolates were susceptible to gentamicin, amikacin, meropenem and imipenem. Obtained results indicate the necessity of Salmonella antibiotic resistance monitoring to gain understanding of Salmonellas’ antibiotic resistance emergence and trends.
Listeria monocytogenes is one of the major food contaminants causing the illness, called Listeriosis. Listeriosis incidence is much less, than the number salmonellosis and campylobacteriosis cases, but the clinical disease is significantly more severe and has a higher mortality. That’s why the development of species-specific PCR techniques to detect L. monocytogenes genome is a topical task. L. monocytogenes bacteria genome detection technique using real-time polymerase chain reaction (qRT-PCR) was improved. The amplification target was a highly specific and suitable for qualification of all strains iap gen, coding L. monocytogenes р60 surface protein. Optimum magnesium concentration (6 mM) and primer annealing temperature (57 °С) were selected. The sensitivity and specificity of the technique were identified. Detection threshold was 120 target molecules. The results obtained demonstrate that optimized qRT-PCR version, based on iap gen amplification, enables to detect L. monocytogenes in animal product and food samples. Optimized qRT-PCR-based screening tests ensure rapid and reliable results.
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