Prevalence, main serovars and anti-microbial resistance profiles of non-typhoidal Salmonella in poultry samples from the Americas: A systematic review and meta-analysis.

Poultry and poultry-derived products such as meat and eggs are among the main sources of non-typhoidal Salmonella (NTS) transmission to humans. Therefore, we performed a systematic review and used random-effects meta-analyses to (1) estimate the prevalence of NTS in poultry samples from birds, products and subproducts and environmental samples, (2) examine the diversity and frequency of their serovars and (3) estimate the prevalence and profiles of anti-microbial resistance (AMR) in NTS isolates reported in studies from the Americas. We included 157 studies from 15 countries comprising 261,408 poultry samples and estimated an overall pooled prevalence of 17.9% (95% Confidence Interval: 10.8-26.3) in birds, 21.8% (17.7-26.1) in products and subproducts and 29.5% (24.2-35.1) in environmental samples. At the national level, the prevalence of NTS was heterogeneous across countries with the highest values in Mexico, the United States and Canada. In total, 131 serovars were identified from 13,388 isolates; Heidelberg, Kentucky, Enteritidis and Typhimurium were the most prevalent in the overall top 10 ranking (range 6.5%-20.8%). At the national level, Enteritidis and Typhimurium were identified in most of the countries, though with national differences in their ranks. The prevalence of AMR increased from 24.1% for 1 antibiotic to 36.2% for 2-3 antibiotics and 49.6% for ≥ 4 antibiotics. Kentucky, Heidelberg, Typhimurium and Enteritidis were the serovars with the highest prevalence of AMR. Besides, tetracycline, ampicillin, streptomycin, ceftiofur and amoxicillin-clavulanic acid were the most frequent antibiotics to which NTS showed resistance. In conclusion, NTS was distributed through the avian production chain with high and heterogeneous values of prevalence in poultry samples. Besides, there were distinctive patterns of serovars distribution across countries and an alarming prevalence of AMR among zoonotic serovars.

Pooled molecular occurrence of Mycoplasma gallisepticum and Mycoplasma synoviae in poultry: A systematic review and meta-analysis.

Worldwide, Mycoplasma gallisepticum (MG) and M. synoviae (MS) are the main agents responsible for chronic respiratory disease in poultry. Therefore, we conducted a systematic review and meta-analysis to estimate their occurrence. We searched electronic databases to find peer-reviewed publications reporting the molecular detection of MG and MS in poultry and used meta-analysis to estimate their pooled global occurrence (combined flock and individual), aggregating results at the regional and national levels. We performed a subgroup meta-analysis for subpopulations (broilers, layers, breeders and diverse poultry including turkeys, ducks and ostriches) and used meta-regression with categorical modifiers. We retrieved 2294 publications from six electronic databases and included 85 publications from 33 countries that reported 62 studies with 22,162 samples for MG and 48 studies with 26,413 samples for MS. The pooled global occurrence was 38.4% (95% CI: 23.5-54.5) for MS and 27.0% (20.4-34.2) for MG. Among regions, Europe and Central Asia had the lowest occurrence for both pathogens, while MG and MS were highly prevalent in South Asia and sub-Saharan Africa, respectively. At the national level, MG occurrence was higher in Algeria, Saudi Arabia and Sudan, whereas China, Egypt and Ethiopia reported higher values of MS. Among the poultry subpopulations, MS and MG were more prevalent in the breeders and layers (62.6% and 31.2%, respectively) than in diverse poultry. The year of publication, the sample size and the level of ambient air pollution (measured indirectly by PM2.5) were associated with the occurrence of both mycoplasmas. Our study revealed high and heterogeneous occurrence values of MG and MS and justifies the need for early detection and improved control measures to reduce the spread of these pathogens.