Antimicrobial Resistance in Invasive Non-typhoid Salmonella from the Democratic Republic of the Congo: Emergence of Decreased Fluoroquinolone Susceptibility and Extended-spectrum Beta Lactamases

Octavie Lunguya,Marie-France Phoba,Sophie Bertrand,Veerle Lejon,Jan Jacobs,Jan Verhaegen,Raymond Vanhoof,Youri Glupczynski,Jean-Jacques Muyembe-Tamfum,Stephen Baker

doi:10.1371/journal.pntd.0002103

Abstract

BackgroundCo-resistance against the first-line antibiotics ampicillin, chloramphenicol and trimethoprim/sulphamethoxazole or multidrug resistance (MDR) is common in non typhoid Salmonella (NTS). Use of alternative antibiotics, such as fluoroquinolones or third generation cephalosporins is threatened by increasing resistance, but remains poorly documented in Central-Africa.Methodology/Principal findingsAs part of a microbiological surveillance study in DR Congo, blood cultures were collected between 2007 and 2011. Isolated NTS were assessed for serotype and antimicrobial resistance including decreased ciprofloxacin susceptibility and extended-spectrum beta-lactamase (ESBL) production. In total, 233 NTS isolates (representing 23.6% of clinically significant organisms) were collected, mainly consisting of Salmonella Typhimurium (79%) and Salmonella Enteritidis (18%). The majority of NTS were isolated in the rainy season, and recovered from children ≤2 years old. MDR, decreased ciprofloxacin susceptibility, azithromycin and cefotaxime resistance were 80.7%, 4.3%, 3.0% and 2.1% respectively. ESBL production was noted in three (1.3%) isolates. Decreased ciprofloxacin susceptibility was associated with mutations in codon 87 of the gyrA gene, while ESBLs all belonged to the SHV-2a type.Conclusions/SignificancePresence of almost full MDR among NTS isolates from blood cultures in Central Africa was confirmed. Resistance to fluoroquinolones, azithromycin and third generation cephalosporins is still low, but emerging. Increased microbiological surveillance in DR Congo is crucial for adapted antibiotic therapy and the development of treatment guidelines.

Highlights

Non typhoid Salmonella (NTS) are among the leading causes of bacterial bloodstream infections in sub-Saharan Africa [1,2].non typhoid Salmonella (NTS) bacteremia mainly affects immune compromised hosts and young children, in whom they are associated with high mortality rates up to 27% [3]
The present study describes the antimicrobial resistance profile of invasive NTS isolates recovered from bloodstream infections during a microbiological surveillance study in DR Congo over the
Worldwide, increased use of these drugs is associated with spread of resistance as well, a phenomenon poorly documented in Central-Africa

Summary

Introduction

Non typhoid Salmonella (NTS) are among the leading causes of bacterial bloodstream infections in sub-Saharan Africa [1,2]. NTS bacteremia mainly affects immune compromised hosts and young children, in whom they are associated with high mortality rates up to 27% [3]. Most cases of invasive non typhoid salmonellosis are due to either Salmonella enterica subsp. Resistance of NTS to the first line antibiotics ampicillin, chloramphenicol and trimethoprim/sulphamethoxazole (TMP-SMX) is usually high [4,5], in the Democratic Republic of the Congo north of the Equator (Figure 2). Malaria is endemic in DR Congo and 97% of the population is living in areas of stable transmission [17]. Typhoid vaccine is not routinely administered [19]

Author Summary

Findings

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