Prevalence of Salmonella associated with chick mortality at hatching and their susceptibility to antimicrobial agents.
ABSTRACT The prevalence of Salmonella associated mortality at hatching was investigated in three hatcheries in Jos, central Nigeria. Their susceptibility to antimicrobial agents was also evaluated. S. Kentucky and S. Hadar were isolated. While half of the isolates were from internal organs, 26.7% came from meconial swabs of dead-in-shell embryos, 17.8% from intestinal samples and 4.4% from egg shells. S. Hadar is known to colonise only the gut and is classified as non-invasive, but in this study 82% were obtained from internal organs which suggests that infections with this serotype may also cause invasive disease. Antimicrobial susceptibility tests showed a high prevalence of antimicrobial resistance in the study area with complete resistance to gentamycin, enrofloxacin, nalidixic acid, tetracycline and streptomycin and substantial resistance to triple sulphur and ciprofloxacin. Six multiple resistance profiles were recorded with a high level of multiple resistance to quinolones. Quinolone resistance has implications for veterinary and human therapy as their misuse in poultry could lead to the emergence of resistant animal and zoonotic pathogens.
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ABSTRACT: Bacteria of the genus Salmonella comprise a large and evolutionary related population of zoonotic pathogens that can infect mammals, including humans and domestic animals, birds, reptiles and amphibians. Salmonella carries a plethora of virulence genes, including fimbrial adhesins, some of them known to participate in mammalian or avian host colonization. Each type of fimbria has its structural subunit and biogenesis genes encoded by one fimbrial gene cluster (FGC). The accumulation of new genomic information offered a timely opportunity to better evaluate the number and types of FGCs in the Salmonella pangenome, to test the use of current classifications based on phylogeny, and to infer potential correlations between FGC evolution in various Salmonella serovars and host niches. This study focused on the FGCs of the currently deciphered 90 genomes and 60 plasmids of Salmonella. The analysis highlighted a fimbriome consisting of 35 different FGCs, of which 16 were new, each strain carrying between 5 and 14 FGCs. The Salmonella fimbriome was extremely diverse with FGC representatives in 8 out of 9 previously categorized fimbrial clades and subclades. Phylogenetic analysis of Salmonella suggested macroevolutionary shifts detectable by extensive FGC deletion and acquisition. In addition, microevolutionary drifts were best depicted by the high level of allelic variation in predicted or known adhesins, such as the type 1 fimbrial adhesin FimH for which 67 different natural alleles were identified in S. enterica subsp. I. Together with strain-specific collections of FGCs, allelic variation among adhesins attested to the pathoadaptive evolution of Salmonella towards specific hosts and tissues, potentially modulating host range, strain virulence, disease progression, and transmission efficiency. Further understanding of how each Salmonella strain utilizes its panel of FGCs and specific adhesin alleles for survival and infection will support the development of new approaches for the control of Salmonellosis.PLoS ONE 06/2012; 7(6):e38596. · 3.53 Impact Factor
- Journal of chemotherapy (Florence, Italy) 10/2012; 24(5):300-4. · 0.83 Impact Factor
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ABSTRACT: To identify the sources of Salmonella contamination, distribution, prevalence, and antimicrobial susceptibility patterns, which have significant impact on public and animal health, and international trade. A total of 1,888 samples were collected by stratified random sampling from 2009 to 2011 from cattle, camels, poultry, fish, vegetables, and humans. All identified Salmonella isolates were serotyped and tested for antimicrobial susceptibility by MIC determinations. A total of 149 Salmonella isolates comprising 17 different serovars were obtained (7.9% prevalence). Salmonella Hadar (37%), S. Eko (17%), S. Enteritidis (10%), S. Kentucky (7%), and S. Uganda (7%) were isolated from different sources. The occurrence of antimicrobial resistance was generally low, but S. Enteritidis and S. Eko showed variable antimicrobial resistance patterns, while all S. Kentucky isolates were resistant to seven out of 17 tested antimicrobials including ciprofloxacin and nalidixic acid. Three S. Hadar isolates revealed reduced susceptibility to ciprofloxacin and susceptibility to nalidixic acid and harbored the plasmid-mediated quinolone resistance gene qnrS1. Salmonella serovars Hadar, Enteritidis and the previously very rarely reported Eko were the major serovars associated with human infections, animal and environmental contamination in the northeastern region of Nigeria. Significance and Impact of the Study: These serovars constitute health risk to poultry, environment and, human population in the region. This article is protected by copyright. All rights reserved.Journal of Applied Microbiology 07/2013; · 2.39 Impact Factor