Identification of Salmonella Bredeney Resistant to Third-Generation Cephalosporins in Saudi Arabia

Ayman Ahmad Al Kraiem,Yingchun Zeng,Xixiang Huo,Tie Chen,Biao Kan,Guang Yang,Jingliang Qin,Kun Yang,Fahd Al Kraiem,Meiying Yan,Yujun Cui

doi:10.3389/fcimb.2019.00390

Abstract

The rapidly increasing prevalence and spread of antibiotic-resistant Salmonella worldwide have become a thorny problem that poses a serious threat to human health. It is speculated that antibiotic abuse, frequent traveling, and mass gatherings accelerate this threat. To explore this hypothesis, we investigated 13 Salmonella isolates from Medina, Saudi Arabia and 15 from China as the control group using typical methods of serotype identification, antibiotic resistance tests, pulsed-field gel electrophoresis (PFGE), and multi-locus sequence typing (MLST). Our results indicated that the isolates from China showed greater serotype diversity and a higher antimicrobial resistance rate, which was consistent with results from other studies in China. In contrast, the Saudi Arabian isolates were mainly identified as Serovar Bredeney and were resistant to a limited number of antibiotics. Interestingly, two of the Bredeney isolates was resistant to third-generation cephalosporins but sensitive to all other tested antibiotics. To confirm the results and understand the underlying molecular mechanisms of these isolates, whole-genome sequencing (WGS) was performed. We discovered that several cephalosporin resistance-associated genes were shared with other strains, but one gene (LEN-23) was unique. Therefore, to the best of our knowledge, we concluded that this study is the first to report the emergence of Salmonella Bredeney resistant to third-generation cephalosporins in Saudi Arabia.

Highlights

The emergence of antibiotic-resistant microbes has become a major problem; the inexorable rise of new resistant isolates has been widely reported, outpacing the rate of replacement of obsolete antibiotics with new effective ones
All isolates from China were susceptible to third-generation cephalosporins, whereas two isolates from Saudi Arabia were resistant but susceptible, to all other tested antibiotics
The occurrence of antimicrobial-resistant Salmonella in Saudi Arabia has been reported by several studies

Summary

Introduction

The emergence of antibiotic-resistant microbes has become a major problem; the inexorable rise of new resistant isolates has been widely reported, outpacing the rate of replacement of obsolete antibiotics with new effective ones. The interventions for reducing the spread of resistance are currently ineffective, and the risk of spreading these resistant microbes increases tremendously when crowds attend mass gatherings. The most prevalent antibiotic-resistant microbe is Salmonella. Salmonella is a gram-negative, motile, non-spore forming, facultative anaerobic, rod-shaped bacterium belonging to the family Enterobacteriaceae (Issenhuth-Jeanjean et al, 2014). Salmonella is considered a primary cause of foodborne illnesses, such as typhoid fever, paratyphoid fever, and food poisoning. Salmonellosis is a major cause of gastroenteritis in both developed and developing countries, which leads to high morbidity and economic burden (Yoshida et al, 2014; Al kraiem et al, 2018)

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