Method for bacteriophage isolation against target Campylobacter strains

Aims: Poultry meat is considered a major source of Campylobacter. This micro-aerobic bacterium is commonly responsible for foodborne illness. This work focuses on the isolation of Campylobacter coli lytic bacteriophages (phages) against target C. coli strains. Methods and Results: A method involving the enrichment of free-range chicken samples in a broth containing the target C. coli strains and salts (CaCl2 and MgSO4) was used for phage isolation. This method allowed the isolation of 43 phages that were active against 83% of the C. coli strains used in the isolation procedure. Approximately 65% of the phages were also effective against Campylobacter jejuni strains. Conclusions: The use of target pathogens in the phage isolation step improves the likelihood of detecting and isolating phages for the control of these specific strains. Significance and Impact of the Study: This technique will be valuable in the context of phage therapy for enriching for phages that are active against specifically identified strains of bacteria, for example from a food poisoning outbreak or epidemic strains resistant to multiple antibiotics. In these situations, using the conventional methods for searching for bacteriophages active for these particular strains can be a time-consuming, if not an unsuccessful process. Using the isolation method described in this manuscript, the particular strains can be added to the enrichment broth increasing the probability of finding phages against them. Therefore, it will shorten the time needed for seeking phages able to lyse target strains, which in most of the cases, because of the rapid increase in antimicrobial-resistant bacteria, is of crucial importance.Fundação para a Ciência e a Tecnologia (FCT

農業協同組合参事に関する一考察

論

Campylobacter Antimicrobial Drug Resistance among Humans, Broiler Chickens, and Pigs, France

We describe isolates from human Campylobacter infection in the French population and the isolates' antimicrobial drug resistance patterns since 1986 and compare the trends with those of isolates from broiler chickens and pigs from 1999 to 2004. Among 5,685 human Campylobacter isolates, 76.2% were C. jejuni, 17.2% C. coli, and 5.0% C. fetus. Resistance to nalidixic acid increased from 8.2% in 1990 to 26.3% in 2004 (p<10-3), and resistance to ampicillin was high over time. Nalidixic acid resistance was greater for C. coli (21.3%) than for C. jejuni (14.9%, p<10-3). C. jejuni resistance to ciprofloxacin in broilers decreased from 31.7% in 2002 to 9.0% in 2004 (p = 0.02). The patterns of resistance to quinolones and fluoroquinolones were similar between 1999 and 2004 in human and broiler isolates for C. jejuni. These results suggest a potential benefit of a regulation policy limiting use of antimicrobial drugs in food animals

Participatory evaluation of chicken health and production constraints in Ethiopia

Chicken production has a major role in the economy of developing countries and backyard production is particularly important to women. Several programmes, in Ethiopia and elsewhere, have attempted to improve chicken production as a means to reduce poverty. A key constraint to chicken production identified by farmers is disease. This study used participatory rural appraisal methods to work with chicken-keepers in order to prioritise chicken diseases, place these within the context of other production constraints, and to explore perceptions of disease risk factors and biosecurity measures. The study, focused on Debre Zeit, Ethiopia, included 71 poultry keepers (41 backyard and 30 semi-intensive chicken producers). Although women played an important role in backyard production systems, semi-intensive farms were more likely to be controlled by men. Participants identified 9 constraints to production: 7 of 8 groups of backyard producers and 15/31 semi-intensive producers ranked diseases as the most important constraint to chicken production. In contrast to previous reports, farmers in both groups had considerable knowledge of diseases and of factors affecting disease risk. Both groups, but particularly semi-intensive producers, highlighted access to feed as a constraint. Many of the challenges faced by both groups were associated with difficulty accessing agricultural and veterinary inputs and expertise. Whilst many of the constraints identified by farmers could be viewed as simply technical issues to be overcome, we believe it is important to recognise the social factors underpinning what are, in reality, relatively modest technical challenges. The low involvement of women in semi-intensive production needs to be recognised by poultry development schemes. Provision needs to be made to allow access to inputs for a wide range of business models, particularly for those, such as women, who have limited access to the capital to allow them to make the jump from backyard to semi-intensive producer, and require support to slowly build up a flock into a profitable venture

RND efflux pumps in P. aeruginosa: an underestimated resistance mechanism

An adequate initial antibiotic therapy is a key determinant of therapeutic success in Pseudomonas aeruginosa - infected patients. Antibiotic effl ux is an underestimated resistance mechanism because it may occur in strains categorized as susceptible. It is rarely or not at all diagnosed in routine laboratories and often masked by high-level resistance mechanism

Biorésistance des Campylobacter des filières avicole et porcine (analyse des transferts de gènes de résistance aux antibiotiques)

Les Campylobacter sont les principales bactéries responsables de gastro-entérites dans le monde. La sensibilité de souches de Campylobacter jejuni et C. coli issues des filières avicoles et porcines françaises a été déterminée vis-à-vis des antibiotiques (ampicilline, acide nalidixique, enrofloxacine, ciprofloxacine, tétracycline, érythromycine et gentamicine) par la méthode de dilution en milieu gélosé. Toutes les souches de Campylobacter étaient sensibles à la gentamicine. Seuls les C. jejuni étaient habituellement sensibles à l'érythromycine. Quelles que soient la filière animale et l'espèce de Campylobacter considérée, les souches étaient inconstamment sensibles à l'ampicilline et aux fluoroquinolones et plus de la moitié des souches étaient résistantes à la tétracycline.Une méthode par filtration sur membranes a été mise au point pour évaluer la sensibilité des Campylobacter vis-à-vis de deux désinfectants : l'hypochlorite de sodium et le chlorure de benzalkonium. Toutes les souches analysées se sont révélées sensibles aux deux désinfectants. Des transferts du gène tetO de résistance à la tétracycline entre souches de C. jejuni ou C. coli ont été mis en évidence in vitro. Les transconjugants sélectionnés en milieu liquide ou en milieu gélosé supplémentés en (tétracycline et ampicilline) ou (tétracycline et enrofloxacine) ont été caractérisés à l'aide d'une PCR-RFLP du gène de la flagelline A. En présence d'enrofloxacine, des mutants devenus résistants à cet antibiotique ont également été observés. Un couple de souches donneur/receveur de C. jejuni a été choisi pour un essai de transfert in vivo chez le poulet. Le transfert spontané du gène tetO a été observé, sans pression de sélection par administration d'antibiotiques aux animaux. Le gène tetO, responsable de la résistance à la tétracycline chez Campylobacter a été localisé sur un plasmide. Cet essai, montre la facilité de transfert du gène tetO entre souches de Campylobacter.LYON1-BU.Sciences (692662101) / SudocSudocFranceF