A significant threat to public health is presented by antibiotic-resistant strains of bacteria, selective pressure on which results from antibiotic use. Colistin is an antibiotic commonly used in veterinary medicine, but also one of last resort in human medicine. Since the 2015 discovery in China of the mcr-1 gene encoding colistin resistance in Enterobacteriaceae, other countries have noted its presence. This study was to find the mcr-1 gene prevalence in E. coli isolated from poultry slaughtered in Poland. Cloacal swabs were taken from December 2017 to October 2018 from broiler chickens in three regions. The samples (n = 158) were grouped as flocks treated with colistin sulphate (n = 87) and those not treated (n = 71). Resistance to antimicrobials commonly used in poultry was evaluated by minimum inhibitory concentration. The presence of the mcr-1 gene was confirmed by PCR. Isolates containing the mcr-1 gene were yielded by 11.27% of the samples from not treated flocks and 19.54% of those from treated flocks, but no statistically significant difference in the prevalence of the gene was seen between the groups. The results clearly preclude intensification of selective pressure for colistin resistance due to colistin sulphate treatment because they show that the avian gastrointestinal tract was already inhabited by colistin-resistant E. coli by the time the chickens came to the poultry house.

Gastrointestinal parasites are some of the most common pathogens which are seriously harmful to the camel’s health. The infection status of gastrointestinal parasites in camels (Camelus bactrianus) in the Tianshan Mountains pastoral area in China is still unclear. The aim of this study was to investigate the species and infection intensity of gastrointestinal tract parasites in local camels. A total of 362 fresh faecal samples were collected and examined for parasite eggs using the saturated saline floating and natural sedimentation method. The parasite eggs were subjected to morphological and molecular examination and identification, and the infection rate and mean intensity of the parasites were analysed. A total of 15 gastrointestinal tract parasite species’ eggs were identified, with a detection rate of 100%. Ostertagia spp. (100%) and Trichostrongylus spp. (98.1%) were dominant. Camels were often coinfected by 5–14 species. The average number of eggs per gram of faeces was higher for Ostertagia spp. (298), Haemonchus contortus (176) and Nematodirus spp. (138). The number of species of parasites infecting young camels was significantly lower than that of adult camels, but the infection intensity in young camels was significantly higher. Gastrointestinal parasites were highly prevalent in camels from the Tianshan Mountains pastoral area in China. This finding provides important epidemiological data for the prevention and control of associated infections in camels.