Listeria monocytogenes is a pathogen that causes infectious diseases in animals and foodborne infection in humans. The aim of this retrospective study was to analyse L. monocytogenes caused abortions in cattle in Latvia in 2013, and to describe the potential reasons of these abortions. In total, 186 cattle abortion cases were investigated. The pathological material from aborted foetuses included samples of brain, heart, liver, spleen, kidneys and lung, liquid of stomach and liquid from thoracic and abdominal cavities. These samples were tested with bacteriological methods according to ISO 11290-1:2007. L. monocytogenes was found in 44 (23.7%) cases of cattle abortions. Positive cases were more distributed in the central and the south-eastern parts of Latvia, because in this territory winters tend to be wetter and colder than in other parts of Latvia. Seasonality was observed of L. monocytogenes caused abortions and the majority of cases occurred during spring and autumn, when the cattle were fed with silage. All abortion cases were observed in the second and the third trimester of the gestation. L. monocytogenes caused abortions occurred in cattle of different ages, but significantly (p is less than 0.05) more often – in 3 years old cattle.

The aim of this study was to investigate the patterns of antibiotic resistance of Aeromonas spp. bacteria isolated from the sea trout (Salmo trutta) from the state fish hatcheries of the Institute of Food Safety, Animal Health and Environment ‘BIOR’, Latvia. Bacteriological investigations were performed at four state fish hatcheries located in the drainage basins of the main Latvian rivers – Daugava, Venta and Gauja, during the five-year period (2012 – 2016). In fish with visible clinical signs, bacteriological samples were collected from heart, liver, spleen, kidney and ulcer surfaces. Aeromonas hydrophila and Aeromonas salmonicida were isolated from sea trouts. A total of 52 individual sea trouts were examined. Resistance to amoxicillin, ampicillin, cephalexin, colistin, doxycycline, enrofloxacin, erythromycin, florfenicol, gentamycin, kanamycin, lincomycin, neomycin, oxytetracycline, spectinomycin, streptomycin, tetracycline, trimethoprim/sulfamethoxazole was tested. The results of this study suggest a multi-drug resistance pattern among the A. hydrophila isolates. All the isolates were resistant to amoxicillin (100%), ampicillin (100%), cephalexin (100%) and erythromycin (100%). The lowest level of resistance was found against florfenicol (4.55%), gentamycin (4.55%), kanamycin (4.55%), but susceptibility was recorded to enrofloxacin, neomycin and trimethoprim/sulfamethoxazole. A. salmonicida isolates were resistant to oxytetracycline (9.38%) and tetracycline (9.38%). For other antibiotics A. salmonicida isolates were susceptible.