Genome Comparison of Erythromycin Resistant Campylobacter from Turkeys Identifies Hosts and Pathways for Horizontal Spread of erm(B) Genes.

Diego Florez-Cuadrado,Ben Pascoe,M C Porrero,Alberto Quesada,Jose L Sáez-Llorente,Samuel K Sheppard,Gema L Orozco,María Ugarte-Ruiz,Lucas Domínguez,Guillaume Meric

doi:10.3389/fmicb.2017.02240

Abstract

Pathogens in the genus Campylobacter are the most common cause of food-borne bacterial gastro-enteritis. Campylobacteriosis, caused principally by Campylobacter jejuni and Campylobacter coli, is transmitted to humans by food of animal origin, especially poultry. As for many pathogens, antimicrobial resistance in Campylobacter is increasing at an alarming rate. Erythromycin prescription is the treatment of choice for clinical cases requiring antimicrobial therapy but this is compromised by mobility of the erythromycin resistance gene erm(B) between strains. Here, we evaluate resistance to six antimicrobials in 170 Campylobacter isolates (133 C. coli and 37 C. jejuni) from turkeys. Erythromycin resistant isolates (n = 85; 81 C. coli and 4 C. jejuni) were screened for the presence of the erm(B) gene, that has not previously been identified in isolates from turkeys. The genomes of two positive C. coli isolates were sequenced and in both isolates the erm(B) gene clustered with resistance determinants against aminoglycosides plus tetracycline, including aad9, aadE, aph(2″)-IIIa, aph(3′)-IIIa, and tet(O) genes. Comparative genomic analysis identified identical erm(B) sequences among Campylobacter from turkeys, Streptococcus suis from pigs and Enterococcus faecium and Clostridium difficile from humans. This is consistent with multiple horizontal transfer events among different bacterial species colonizing turkeys. This example highlights the potential for dissemination of antimicrobial resistance across bacterial species boundaries which may compromise their effectiveness in antimicrobial therapy.

Highlights

The World Health Organization (WHO) has recently published a list of bacteria for which new antibiotic therapies are urgently needed, with Campylobacter classified as high priority (WHO, 2017)
Food Safety Authority (EFSA) criteria for quantifying multidrug resistance (MDR; resistance to at least three classes of antimicrobials tested), seven MDR profiles were recorded for Campylobacter isolates (Table 1) (European Food Safety Authority [EFSA]/European Centre for Disease Prevention and Control [ECDC], 2017)
Seventy-nine C. coli isolates (59.4%) and three C. jejuni isolates (8.5%) showed resistance to ciprofloxacin and erythromycin

Summary

Introduction

The World Health Organization (WHO) has recently published a list of bacteria for which new antibiotic therapies are urgently needed, with Campylobacter classified as high priority (WHO, 2017). This is of concern as campylobacteriosis is the most commonly notified bacterial foodborne infection in the European Union (European Food Safety Authority [EFSA]/European Centre for Disease Prevention and Control [ECDC], 2016a). Treatment of severe infection occasionally requires antimicrobial therapy, often with erythromycin (European Food Safety Authority [EFSA]/European Centre for Disease Prevention and Control [ECDC], 2016b) and to a lesser extent with gentamicin, the later used occasionally when infection becomes systemic (Lehtopolku et al, 2009). Fluoroquinolones were commonly used in the past, the rising of resistance among Campylobacter isolates makes these antibiotics ineffective (Kassem et al, 2016)

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Conclusion