Diversity and Antimicrobial Resistance Genotypes in Non-Typhoidal Salmonella Isolates from Poultry Farms in Uganda.

Terence Odoch,Helge Christoffer Høgberg Hansen,Camilla Sekse,Clovice Kankya,Yngvild Wasteson,Trine M L'Abee-Lund

doi:10.3390/ijerph15020324

Abstract

Non-typhoidal Salmonella (NTS) are foodborne pathogens of global public health significance. The aim of this study was to subtype a collection of 85 NTS originating from poultry farms in Uganda, and to evaluate a subgroup of phenotypically resistant isolates for common antimicrobial resistance genes and associated integrons. All isolates were subtyped by pulsed-field gel electrophoresis (PFGE). Phenotypically resistant isolates (n = 54) were screened by PCR for the most relevant AMR genes corresponding to their phenotypic resistance pattern, and all 54 isolates were screened by PCR for the presence of integron class 1 and 2 encoding genes. These genes are known to commonly encode resistance to ampicillin, tetracycline, ciprofloxacin, trimethoprim, sulfonamide and chloramphenicol. PFGE revealed 15 pulsotypes representing 11 serotypes from 75 isolates, as 10 were non-typable. Thirty one (57.4%) of the 54 resistant isolates carried at least one of the seven genes (blaTEM-1, cmlA, tetA, qnrS, sul1, dhfrI, dhfrVII) identified by PCR and six (11%) carried class 1 integrons. This study has shown that a diversity of NTS-clones are present in Ugandan poultry farm settings, while at the same time similar NTS-clones occur in different farms and areas. The presence of resistance genes to important antimicrobials used in human and veterinary medicine has been demonstrated, hence the need to strengthen strategies to combat antimicrobial resistance at all levels.

Highlights

Salmonella enterica subsp. enterica include serotypes that are global foodborne pathogens significantly affecting public health and economy [1,2,3]
This study evaluated a limited number of resistance genes and only on phenotypically resistant isolates from a previous study [30], the sample size was quite small and samples were collected from only three districts that were purposively selected
The occurrence of antimicrobial resistance (AMR) genes and integrons in Salmonella enterica isolates from Ugandan poultry has been unveiled, and through subtyping, the diversity of non-typhoidal Salmonella (NTS) isolates from three districts in Uganda has been explored

Summary

Introduction

Salmonella enterica subsp. enterica include serotypes that are global foodborne pathogens significantly affecting public health and economy [1,2,3]. Enterica include serotypes that are global foodborne pathogens significantly affecting public health and economy [1,2,3]. Salmonellosis is classified into typhoid and non-typhoidal salmonellosis. Most cases of non-typhoidal Salmonella (NTS) disease are associated with consumption of contaminated foods of animal origin, poultry, meat and in some instances vegetables [4,5,6]. NTS is estimated to cause 93.8 million cases of gastroenteritis annually, of which 80 million cases are foodborne and causing 155,000 deaths [7]. African countries have low estimated cases of NTS gastroenteritis compared to other parts of the world, they have a much higher level of invasive non-enteric NTS infections [7,8].

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