Chicken faecal microbiota and disturbances induced by single or repeated therapy with tetracycline and streptomycin

BACKGROUND: In this study, we characterised the microbiota present in the faeces of 15- and 46-week-old egg laying hens before and after tetracycline or streptomycin therapy. In the first experiment, the layers were subjected to 7 days of therapy. In the second experiment, the hens were subjected to two days of therapy, which was repeated for an additional two days after 12 days of antibiotic withdrawal. This enabled us to characterise dynamics of the changes after antibiotic administration and withdrawal, and to identify genera repeatedly resistant to tetracycline and streptomycin. RESULTS: Real-time PCRs specific for Enterobacteriales, Lactobacillales, Clostridiales and Bifidobacteriales showed that changes in the microbiota in response to antibiotic therapy and antibiotic withdrawal were quite rapid and could be observed within 24 hours after the change in therapy status. Pyrosequencing of PCR amplified V3/V4 variable regions of 16S rRNA genes showed that representatives of the orders Clostridiales, Lactobacillales, Bacteroidales, Bifidobacteriales, Enterobacteriales, Erysipelotrichales, Coriobacteriales, Desulfovibrionales, Burkholderiales, Campylobacterales and Actinomycetales were detected in the faeces of hens prior to the antibiotic therapy. Tetracycline and streptomycin therapies decreased the prevalence of Bifidobacteriales, Bacteroidales, Clostridiales, Desulfovibrionales, Burkholderiales and Campylobacterales in faecal samples in both experiments. On the other hand, Enterobacteriales and Lactobacillales always increased in prevalence in response to both therapies. Within the latter two orders, Escherichia and Enterococcus were the genera prevalence of which increased after all the antibiotic treatments. CONCLUSIONS: The changes in microbiota composition induced by the antibiotic therapy were rapid and quite dramatic and only representatives of the genera Enterococcus and Escherichia increased in response to the therapy with both antibiotics in both experiments

Entrepreneurial orientation and the business performance of SMEs: a quantitative study from the Netherlands

Additional file 5. Macrophage proteins responding to in vivo infection with S. Enteritidis

Advanced database mining integrating sequence and structure bioinformatics with microfluidics challenges enzyme engineering

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Cats as a Risk for Transmission of Antimicrobial Drug-resistant Salmonella

Cats can shed antimicrobial drug−resistant Salmonella serotypes in the environment

Charakterizace genu antibioticke rezistence u kmenu Salmonella Typhimurium izolovanych na uzemi Ceske republiky.

In 1985, a new clone of pentadrug resistant Salmonella enterica serovar Typhimurium appeared. Since that time it has spread throughout the world. In this study we focused on the introduction of this clone in the Czech Republic and in the evolution of the resistance to antibiotics in general. In a collection of 66 strains isolated from 1984 to 2002, genes coding for the antibiotic resistance were determined using specific PCRs and DNA sequencing. We found that the pentadrug resistant clone first appeared in the Czech Republic in 1990. The genetic basis of the antibiotic resistance in strains isolated before this date was considerably different from that observed in present strains. Strains isolated in 1984-85 were typical by the presence of blaTEM, cat, strA, strB, sul2, tetB and tetC genes. Most of these strains were free of integrons. Rarely isolated integron-positive strains from this period were always of different genetic composition from recent isolates i.e. they never coded blaPSE-1, floR, aadA2 and tetG. Such genes are on the other hand found in 80% of present antibiotic resistant strains. According to our previous results we speculate that these resistant genes are localised on plasmids of high molecular weight. In a single strain isolated in 1991 we found a new variant of aadA gene designated as aadA21 gene, 5' end of which was identical with aadA2 and 3' end of which was identical with aadA1. This finding furher confirms the introduction and mixing of a new bacterial population in the beginning of the 90s in the Czech Republic.Several parts of the text in English.Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

Transient and Prolonged Response of Chicken Cecum Mucosa to Colonization with Different Gut Microbiota

In this study we determined protein and gene expression in the caeca of newly hatched chickens inoculated with cecal contents sourced from hens of different ages. Over 250 proteins exhibited modified expression levels in response to microbiota inoculation. The most significant inductions were observed for ISG12-2, OASL, ES1, LYG2, DMBT1-L, CDD, ANGPTL6, B2M, CUZD1, IgM and Ig lambda chain. Of these, ISG12-2, ES1 and both immunoglobulins were expressed at lower levels in germ-free chickens compared to conventional chickens. In contrast, CELA2A, BRT-2, ALDH1A1, ADH1C, AKR1B1L, HEXB, ALDH2, ALDOB, CALB1 and TTR were expressed at lower levels following inoculation of microbiota. When chicks were given microbiota preparations from different age donors, the recipients mounted differential responses to the inoculation which also differed from the response profile in naturally colonised birds. For example, B2M, CUZD1 and CELA2A responded differently to the inoculation with microbiota of 4- or 40-week-old hens. The increased or decreased gene expression could be recorded 6 weeks after the inoculation of newly hatched chickens. To characterise the proteins that may directly interact with the microbiota we characterised chicken proteins that co-purified with the microbiota and identified a range of host proteins including CDD, ANGPTL6, DMBT1-L, MEP1A and Ig lambda. We propose that induction of ISG12-2 results in reduced apoptosis of host cells exposed to the colonizing commensal microbiota and that CDD, ANGPTL6, DMBT1-L, MEP1A and Ig lambda reduce contact of luminal microbiota with the gut epithelium thereby reducing the inflammatory response

Retron reverse transcriptase rrtT is ubiquitous in strains of Salmonella enterica serovar Typhimurium

Bacterial retron reverse transcriptases are unusual enzymes which utilise the same RNA molecule as a template and also as a primer for initiation of the reverse transcription. Except for their relatively frequent presence in Myxococcus spp., they are considered as quite rare proteins. However, in this study we proved that retron reverse transcriptase is frequently found in certain serovars of Salmonella enterica. Using polymerase chain reaction (PCR), in strains of serovar Typhimurium, the rrtT (retron reverse transcriptase Typhimurium) gene was detected in 158 out of 175 tested field strains. On the other hand, in none of the 18 tested serovar Enteritidis strains the rrtT was detected in their genome. Detailed computer analysis allowed us to predict the sequence of msDNA and to propose that the final msDNA is free of any RNA. Furthermore, we predict that there are at least three different classes of retron reverse transcriptases