Prevalence and risk factors for Salmonella spp. contamination in broiler chicken farms and slaughterhouses in the northeast of Algeria

Aim: The aim of this study was to provide information on the prevalence of Salmonella serotypes and to identify risk factors for Salmonella spp. contamination in broiler chicken farms and slaughterhouses in the northeast of Algeria. Materials and Methods: This study was conducted on 32 poultry farms and five slaughterhouses in the province of Skikda (northeastern Algeria). A questionnaire was answered by the poultry farmers and slaughterhouses' managers. Biological samples (cloacal swabs, droppings, caeca, livers, and neck skins) and environmental ones (water, feed, surface wipes, rinsing water, and sticking knife swabbing) were taken to assess the Salmonella contamination status. Results: Nearly 34.37% of the poultry farms and all the slaughterhouses were contaminated with Salmonella. The isolated Salmonella strains belonged to two major serotypes: Kentucky and Heidelberg followed by Enteritidis, Virginia, and Newport. There was an evident heterogeneous distribution of serotypes in poultry farms and slaughterhouses. Only one factor (earth floor) was significantly associated with Salmonella contamination in poultry houses (p<0.05). Conclusion: A high prevalence rate of Salmonella contamination was found in poultry farms and slaughterhouses in Skikda region. These results showed the foremost hazardous role of poultry production in the spread and persistence of Salmonella contamination in the studied region

New Method for Solving the Inverse Thermal Conduction Problem (θ-Scheme Combined with CG Method under Strong Wolfe Line Search)

Most thermal researchers have solved thermal conduction problems (inverse or direct) using several different methods. These include the usual discretization methods, conventional and special estimation methods, in addition to simple synchronous gradient methods such as finite elements, including finite and special quantitative methods. Quantities found through the finite difference methods, i.e., explicit, implicit or Crank–Nicolson scheme method, have also been adopted. These methods offer many disadvantages, depending on the different cases; when the solutions converge, limited range stability conditions. Accordingly, in this paper, a new general outline of the thermal conduction phenomenon, called (θ-scheme), as well as a gradient conjugate method that includes strong Wolfe conditions has been used. This approach is the most useful, both because of its accuracy (16 decimal points of importance) and the speed of its solutions and convergence; by addressing unfavorable adverse problems and stability conditions, it can also have wide applications. In this paper, we applied two approaches for the control of the boundary conditions: constant and variable. The θ-scheme method has rarely been used in the thermal field, though it is unconditionally more stable for θ∈ [0.5, 1]. The simulation was carried out using Matlab software

Prevalence and genotypic characterization of Salmonella spp. from chicken meats marketed in the province of Skikda, Algeria

International audienceHere, we aim to determine the prevalence of Salmonella contamination of poultry meat from butcheries of the province of Skikda and to investigate antibiotic resistance. Salmonella spp. isolates were screened from 70 samples, including chicken breasts (n = 40 samples) and chicken thighs (n = 30 samples) collected from 14 butcheries. All suspected Salmonella colonies from selective media were confirmed by MALDI-TOF MS and serotyped. The susceptibility profile to 16 antibiotics was studied. According to the antibiotic susceptibility results, resistance genes were investigated by standard PCR targeting various genes such as blaSHV, blaTEM, aac3, aac6-Ibcr, aad, qnrA and qnrB. Of the 14 butcheries studied, samples from eight butcheries were contaminated with Salmonella (57.14%). 19 Salmonella strains were isolated, including five serotypes with a predominance of Kentucky serotype (n = 9), Enteridis (n = 3), followed by Heidelberg (n = 3), Virchow (n = 3), and Manhattan (n= 1). All isolates were resistant to Rifampicin (100%; n = 19), and to other antibiotics such as Ciprofloxacin (47.36%), Amoxicillin-clavulanic acid (47.36%; n = 9), Amoxicillin, (47.36%; n = 9), Ticarcillin-clavulanic acid (47.36%; n = 9), and Gentamycin (47.36%; n = 9). All isolates showing multidrug resistance (47.36%; n = 9) were positive by PCR to the blaTEM-1 β-lactamase gene, from which 8 strains carried the aminoglycoside resistance aad7 gene. However, none was positive for the tested blaSHV, Aac3, Aac6-Ibcr, qnrA, qnrB, ArmA and ArmB genes. Our findings show a worrying rate of Salmonella contamination of poultry meats

Concept development and experimentation of a Phase Change Material (PCM) enhanced domestic hot water

International audienc

Prevalence and clonal relationship of ESBL-producing Salmonella strains from humans and poultry in northeastern Algeria

International audienceBackground: The aims of this study were to investigate Salmonella contamination in broiler chicken farms and slaughterhouses, to assess the antibiotic resistance profile in avian and human Salmonella isolates, and to evaluate the relationship between avian and human Extended Spectrum beta-Lactamase (ESBL)-producing isolates. Salmonella was screened in different sample matrices collected at thirty- two chicken farms and five slaughterhouses. The human isolates were recovered from clinical specimens at the University Teaching Hospital of Constantine (UTH). All suspected colonies were confirmed by MALDI-TOF (Matrix Assisted Laser Desorption Ionization Time OF light) and serotyped. Susceptibility testing against 13 antibiotics including, amoxicillin/clavulanic acid, ticarcillin, cefoxitin, cefotaxime, aztreonam, imipenem, ertapenem, gentamicin, amikacin, ciprofloxacin, colistin, trimethoprim/sulfamethoxazole and fosfomycin, was performed using the disk diffusion method on Mueller-Hinton agar. ESBL-production was screened by the double-disk synergy test and confirmed by molecular characterization using PCR (polymerase chain reaction) amplification and sequencing of ESBL encoding genes. Clonality of the avian and human strains was performed using the Multi Locus Sequencing Typing method (MLST). Results: Forty-five isolated avian Salmonella strains and 37 human collected ones were studied. Five S. enterica serotypes were found in avian isolates (mainly Kentucky) and 9 from human ones (essentially Infantis). 51.11% and 26.6% of the avian isolates were resistant to ciprofloxacin and cefotaxime, respectively, whereas human isolates were less resistant to these antibiotics (13.5% to ciprofloxacin and 16.2% to cefotaxime). Eighteen (12 avian and 6 human) strains were found to produce ESBLs, which were identified as bla(CTX-M-1) (n = 12), bla(CTX-M-15) (n = 5) and bla(TEM) group (n = 8). Interestingly, seven of the ESBL-producing strains (5 avian and 2 human) were of the same ST (ST15) and clustered together, suggesting a common origin. Conclusion: The results of the combined phenotypic and genotypic analysis found in this study suggest a close relationship between human and avian strains and support the hypothesis that poultry production may play a role in the spread of multidrug-resistant Salmonella in the human community within the study region