VERY few veterinary surgeons have thought fit to write a book on diseases of poultry. Mr. Ernest Gray has done justice to the subject and is to be congratulated on his effort. A book of this size, written by one with specialized knowledge, will add to the value of any library or private bookshelf. Diseases of Poultry Their Aetiology, Diagnosis, Treatment and Control; with a Section on the Normal Anatomy and Physiology of the Fowl. By Ernest Gray. (Lockwood's Agricultural and Horticultural Handbooks.) Pp. x + 198 + 16 plates. (London: Crosby Lockwood and Son, Ltd., 1940.) 9s. 6d. net.

Diseases of Poultry

Restricting the use of antibiotics in food-producing animals and its associations with antibiotic resistance in food-producing animals and human beings: a systematic review and meta-analysis

The epidemiology of antibiotic resistance in Campylobacter.

Antimicrobial resistance is a public health threat. Because antimicrobial consumption in food-producing animals contributes to the problem, policies restricting the inappropriate or unnecessary agricultural use of antimicrobial drugs are important. However, this link between agricultural antibiotic use and antibiotic resistance has remained contested by some, with potentially disruptive effects on efforts to move towards the judicious or prudent use of these drugs. The goal of this review is to systematically evaluate the types of evidence available for each step in the causal pathway from antimicrobial use on farms to human public health risk, and to evaluate the strength of evidence within a ‘Grades of Recommendations Assessment, Development and Evaluation‘(GRADE) framework. The review clearly demonstrates that there is compelling scientific evidence available to support each step in the causal pathway, from antimicrobial use on farms to a public health burden caused by infections with resistant pathogens. Importantly, the pathogen, antimicrobial drug and treatment regimen, and general setting (e.g., feed type) can have significant impacts on how quickly resistance emerges or spreads, for how long resistance may persist after antimicrobial exposures cease, and what public health impacts may be associated with antimicrobial use on farms. Therefore an exact quantification of the public health burden attributable to antimicrobial drug use in animal agriculture compared to other sources remains challenging. Even though more research is needed to close existing data gaps, obtain a better understanding of how antimicrobial drugs are actually used on farms or feedlots, and quantify the risk associated with antimicrobial use in animal agriculture, these findings reinforce the need to act now and restrict antibiotic use in animal agriculture to those instances necessary to ensure the health and well-being of the animals.

/pdf/antimicrobial-drug-use-in-food-producing-animals-and-5ce45olsql.pdf

Antimicrobial drug use in food-producing animals and associated human health risks: what, and how strong, is the evidence?

SUMMARY. Control of pathogenic avian mycoplasmas can consist of one of three general approaches: Maintaining flocks free of infection, medication, or vaccination. Maintaining flocks free of pathogenic mycoplasmas consists of maintaining replacements from mycoplasma-free sources in a single-age, all-in all-out management system. Good biosecurity and an effective monitoring system are necessary aspects of this program. Medication can be very useful in preventing clinical signs and lesions, as well as economic losses, but cannot be used to eliminate infection from a flock and is therefore not a satisfactory long-term solution. Vaccination against Mycoplasma gallisepticum (MG) or M. synoviae (MS) can be a useful long-term solution in situations where maintaining flocks free of infection is not feasible, especially on multi-age commercial egg production sites.

https://bioone.org/journals/avian-diseases/volume-52/issue-3/8323-041808-Review.1/Control-of-Avian-Mycoplasma-Infections-in-Commercial-Poultry/10.1637/8323-041808-Review.1.pdf

Control of Avian Mycoplasma Infections in Commercial Poultry

Objectives: The antimicrobial susceptibility of Campylobacter strains isolated from standard and freerange broilers in 1992–1996 and 2001–2002 was studied. Methods: Strains were isolated from caeca or skin samples collected from standard or free-range broilers arriving in slaughterhouses. The MICs of ampicillin, nalidixic acid, enrofloxacin, tetracycline, erythromycin and gentamicin were determined by agar dilution and compared according to species (Campylobacter jejuni or Campylobacter coli ), production system and sampling period. Results: Results showed that all chickens harboured Campylobacter. An increase over time of the C. coli/C. jejuni ratio for standard chickens occurred. A wide range of MICs was observed among isolates from the same broiler or from the same farm. Strains collected on entry to the slaughterhouse and after storage showed no significant difference in their antibiotic resistance. C. coli was more resistant than C. jejuni to tetracycline and erythromycin during the first period and to all tested molecules (except gentamicin) during the second period. Strains isolated from standard chickens were also more often resistant than those isolated from free-range broilers. The percentage of C. jejuni strains resistant to ampicillin decreased from 1992–1996 to 2001–2002, whereas no change could be observed for the other antimicrobial agents. However, for C. coli the resistance to ampicillin, nalidixic acid, enrofloxacin, tetracycline and erythromycin significantly increased. Conclusion: There was an increase in the incidence of antibiotic resistance of C. coli between 1992–1996 and 2001–2002.

Antimicrobial resistance in Campylobacter strains isolated from French broilers before and after antimicrobial growth promoter bans

Detection of Mycoplasma synoviae in poultry environment samples by culture and polymerase chain reaction

Comparison of pulsed-field gel electrophoresis with random amplified polymorphic DNA for typing of Mycoplasma synoviae.

Epidemiological study on Mycoplasma synoviae infection in layers

The polymerase chain reaction (PCR) was used to detect Mycoplasma gallisepticum in samples collected from the environment of experimentally or naturally infected poultry. Culture was also used in the experimental infections. Of 160 samples of food, drinking water, feathers, droppings or dust collected during experimental infection, 103 were positive using a M. gallisepticum-specific PCR (MG-PCR) and 68 were positive using a PCR (mycoplasma-PCR) that detects all species of the genera Mycoplasma, Spiroplasma, Acholeplasma and Ureaplasma. Six of these samples were also positive by culture. In environmental samples collected on a depopulated M. gallisepticum-positive turkey farm, three and two out of a total of 12 were positive by mycoplasma-PCR and MG-PCR, respectively. These results indicate the disseminating capacity of this mycoplasma and the possible use of PCR methods for epidemiological analyses and control of farm decontamination before the introduction of new birds.

https://www.tandfonline.com/doi/pdf/10.1080/03079450120118658

Fabienne Dufour-Gesbert

Papers

Antimicrobial resistance in Campylobacter strains isolated from French broilers before and after antimicrobial growth promoter bans

Detection of Mycoplasma synoviae in poultry environment samples by culture and polymerase chain reaction

Comparison of pulsed-field gel electrophoresis with random amplified polymorphic DNA for typing of Mycoplasma synoviae.

Epidemiological study on Mycoplasma synoviae infection in layers

Polymerase chain reaction for detection of Mycoplasma gallisepticum in environmental samples.