Molecular Typing of Pseudomonas aeruginosa Isolates Collected in Abidjan Hospitals (Côte d'Ivoire) Using the Multiple-Locus Variable Number of Tandem Repeats Method

Abstract

Background/objectives:Pseudomonas aeruginosa can cause community-acquired infections affecting various body sites. The present retrospective study investigated the genetic diversity of 173 isolates (166 clinical, 7 environmental) of P. aeruginosa collected from clinical pathology laboratories in Abidjan, Côte d'Ivoire (2001-2011). Methods: Multiple-Locus Variable Number of Tandem Repeats (VNTR) Analysis (MLVA) using 13 loci was applied to all isolates and compared to published MLVA data. The antibiotics status of the isolates was compiled when available and compared to published profiles. Results: Among 95 isolates analyzed for their antibiotics status, 14 displayed concerning resistance profiles: five multidrug-resistant (MDR) and nine extensively drug-resistant (XDR). MLVA typing revealed a high genetic diversity (>130 genotypes), with many genotypes represented by a single strain. Notably, thirteen clusters (≥4 related isolates) were observed. Some clusters displayed close genetic relatedness to isolates from France, Korea, and well-studied strains (ST560, LES and PA14). Comparative analysis suggested the presence of international high-risk MDR clones (CC233, CC111) in Côte d'Ivoire. Importantly, MLVA clustering revealed a close relationship of CC235-MDR strains with a locally identified cluster (group 9). Conclusions: These findings support MLVA as a reliable and cost-effective tool for low-resource settings, allowing the selection of relevant strains for future whole genome sequence analyses. This approach can improve outbreak investigations and public health interventions aimed at curbing MDR P. aeruginosa transmission within hospitals and at the national level.

Keywords: Côte d’Ivoire; MLVA; Pseudomonas aeruginosa; epidemiology; genotyping; multidrug-resistant.

Figure 1

Antimicrobial resistance pattern of P. aeruginosa isolates from CeDReS collected in 2001–2011; piperacillin (PIP), ticarcillin (TIC), cefsulodin (CFS), ceftazidim (CAZ), aztreonam (ATM), imipenem (IPM), amikacin (AMK), tobramycin (TOB), gentamicin (GEN), netilmicin (NET), and ciprofloxacin (CIP).

Figure 2

Minimum Spanning Tree (MST) analysis based on the MLVA-13 profile of 173 P. aeruginosa isolates collected in Côte d’Ivoire compared with 36 strains of various origins. Each circle represents a genotype, and the circle size is proportional to the number of samples within that specific genotype. Branch lengths above three are dashed. The 13 clusters identified by UPGMA (Figure S2) and comprising 82 isolates from Côte d’Ivoire are colored as indicated. The other isolates are singletons or belong to smaller clusters.

Figure 3

MSTs showing the global distribution of P. aeruginosa isolates, with (A) 173 isolates of Ivorian origin in red and 408 cystic fibrosis isolates from Europe in open circles. (B) Ivorian isolates with 127 international-MDR strains shown in orange. The circle size is proportional to the number of samples within that specific genotype.