The objective of the present study was to examine the effects of hydrocolloidal silver nanoparticles (Ag-nano) on microbial profile of caecum and morphology of enterocytes in duodenum of Japanese quail, as a model animal for poultry. Quails (Coturnix coturnix japonica) (10 d old) were randomly divided into four groups (15 quails each) and located into four cages for 12 days. Quails were fed with granulated diets given ad libitum and had free access to drinking water. Ag-nano were added to drinking water at concentrations of 0, 5, 15 and 25 mg/kg. At the end of the experiment, the animals were killed and samples of duodenum and caeca microflora were collected. This initial investigation demonstrated that silver nanoparticles did not influence emphatically microflora of quail caecum; however, water containing 25 mg/kg of Ag-nano significantly increased the population of lactic acid bacteria. Furthermore, Ag-nano did not show any damaging properties on enterocytes of duodenal villi.

Bacterial colonization of the chicken gut by environmental microbes begins immediately after hatching. Composition of the intestinal microbiota is dependent on the surrounding environment, diet variation, pathological conditions, antibiotic therapy, and others. The genomes of all these intestinal microbes form a microbiome which by far outnumbers the host's genome. As a consequence, the microbiome provides additional metabolic functions to the host, including nutrient utilization and absorption, fermentation of non-digestible dietary fiber, synthesis of some vitamins, biotransformation of bile acids, and the well-being of their chicken host. Microorganisms can also directly interact with the lining of the gastrointestinal tract, which may alter the physiology and immunological status of the bird. Since newly hatched broiler chickens demonstrate delayed commensal colonization and low bacterial diversity, the most effective and harmless method available to control the development and composition of the intestinal microbiota is a competitive exclusion treatment by applying probiotic bacteria. Additionally, recent research has shown that probiotic bacteria have a variety of beneficial effects, including counteraction of dysbiosis, promotion of gut health and homeostasis, enhancement of immune defenses and antagonization of infectious agents.

The antimicrobial susceptibility of Escherichia coli isolates associated with various types of infections in dogs and cats was determined. The studied isolates were most frequently susceptible to fluoroquinolones and the extended-spectrum cephalosporins (ESCs), antimicrobials commonly used in treatment of infections in companion animals. However, an increase in the percentage of strains resistant to β-lactam antibiotics including ESCs was noted between January 2007 and December 2013. The frequency of multidrug-resistant (MDR) E. coli isolation (66.8% of isolates) is alarming. Moreover, the statistically significant increase of the percentage of MDR isolates was observed during the study period. No difference in the prevalence of multidrug resistance was found between bacteria causing intestinal and extraintestinal infections and between canine and feline isolates. Nonhemolytic E. coli isolates were MDR more often than hemolytic ones. Our study showed the companion animals in Poland as an important reservoir of MDR bacteria. These results indicate that continuous monitoring of canine and feline E. coli antimicrobial susceptibility is required. Furthermore, introduction and application of recommendations for appropriate use of antimicrobials in small animal practice should be essential to minimize the emergence of multidrug resistance among E. coli in companion animals.

The purpose of the study was to examine of bacteria present in chicken embryos and newly hatched chicks. The bacteria were determined quantitatively in caecal contents, liver and yolk sac of 25 embryos at 18 day of incubation, 25 embryos at 20 day incubation, and 25 newly hatched chicks.

The spread of resistance to antibiotics is a major health concern worldwide due to the increasing rate of isolation of multidrug resistant pathogens hampering the treatment of infections. The food chain has been recognized as one of the key routes of antibiotic resistant bacteria transmission between animals and humans. Considering that lactic acid bacteria (LAB) could act as a reservoir of transferable antibiotic resistance genes, LAB strains intended to be used as feed additives should be monitored for their safety. Sixty-five LAB strains which might be potentially used as probiotic feed additives or silage inoculants, were assessed for susceptibility to eight clinically relevant antimicrobials by a minimum inhibitory concentration determination. Among antimicrobial resistant strains, a prevalence of selected genes associated with the acquired resistance was investigated. Nineteen LAB strains displayed phenotypic resistance to one antibiotic, and 15 strains were resistant to more than one of the tested antibiotics. The resistance to aminoglycosides and tetracyclines were the most prevalent and were found in 37 and 26% of the studied strains, respectively. Phenotypic resistance to other antimicrobials was found in single strains. Determinants related to resistance phenotypes were detected in 15 strains as follows, the aph(3″)-IIIa gene in 9 strains, the lnu(A) gene in three strains, the str(A)-str(B), erm(B), msr(C), and tet(M) genes in two strains and the tet(K) gene in one strain. The nucleotide sequences of the detected genes revealed homology to the sequences of the transmissible resistance genes found in lactic acid bacteria as well as pathogenic bacteria. Our study highlights that LAB may be a reservoir of antimicrobial resistance determinants, thus, the first and key step in considering the usefulness of LAB strains as feed additives should be an assessment of their antibiotic resistance. This safety criterion should always precede more complex studies, such as an assessment of adaptability of a strain or its beneficial effect on a host. These results would help in the selection of the best LAB strains for use as feed additives. Importantly, presented data can be useful for revising the current microbiological cut-off values within the genus Lactobacillus and Pediococcus.