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Published on: October 18, 2019
Detection of CTX-M-15 ESBL in XDR Haemophilus parainfluenzae from a urethral swab
François Caméléna1,2,3, Manel Merimèche1,2,3, Mathilde Liberge1,2
1Université de Paris Cité, INSERM, IAME, Paris F-75018, France.
Objectives:
Haemophilus parainfluenzae is an opportunistic pathogen causing respiratory tract infection and sexually transmitted diseases. The emergence of multidrug resistance in this species is particularly worrisome, especially since the recent description of CTX-M-15 ESBL-producing isolates in Spain. The aim of this study was to characterize a CTX-M-15-producing H. parainfluenzae clinical isolate, HP01, obtained from a urethral swab.
Methods:
MICs were determined with gradient strips for this isolate. Hydrolysis assays were performed with the β LACTA test. Genomic DNA from HP01 was subjected to Illumina and Oxford Nanopore sequencing to investigate the genetic environment of blaCTX-M-15. Phylogenetic analysis was performed with available H. parainfluenzae genomes from the NCBI database, including CTX-M-15 producers.
Results:
HP01, an XDR isolate, was resistant to penicillin, third-generation cephalosporins, fluoroquinolones, macrolides, cyclines and co-trimoxazole and susceptible only to carbapenems and rifampicin. HP01 carried blaTEM-1, blaCTX-M-15, tet(M), catS and mef(E)/mel and harboured amino acid substitutions in PBP3, PBP5, GyrA, ParC and FolA implicated in resistance. Genomic analysis revealed that blaCTX-M-15 was carried by a Tn3-like transposon inserted into a novel integrative and conjugative element (ICE), ICEHpaSLS, present on the chromosome and belonging to the ICEHin1056 family described in Haemophilus influenzae. The tet(M)-MEGA element was also detected on the chromosome. No plasmid was found. The phylogenetic analysis showed that four H. parainfluenzae producing CTX-M-15 clustered in the same clade.
Conclusions:
Here we report the description of an XDR H. parainfluenzae producing blaCTX-M-15 isolated from a urethral swab. The blaCTX-M-15 gene was inserted into an ICE structure similar to those recently described in CTX-M-15 producers in Spain. The emergence of XDR H. parainfluenzae producing blaCTX-M-15 is a matter of great concern. Careful surveillance is required to prevent its spread.
Insights
This study characterizes an extensively drug-resistant Haemophilus parainfluenzae isolate producing the CTX-M-15 enzyme, a significant concern for public health. Surveillance is crucial to prevent the spread of this multidrug-resistant pathogen.
Area of Science:
- Medical Microbiology
- Genomics
- Antimicrobial Resistance
Background:
- Haemophilus parainfluenzae is an opportunistic pathogen causing respiratory and sexually transmitted infections.
- The emergence of multidrug resistance, particularly CTX-M-15 extended-spectrum beta-lactamase (ESBL) producers, is a growing global health concern.
- Recent reports highlight CTX-M-15-producing H. parainfluenzae isolates in Spain, necessitating further characterization.
Purpose of the Study:
- To characterize a clinical isolate of H. parainfluenzae (HP01) producing the blaCTX-M-15 gene.
- To investigate the genetic environment and resistance mechanisms of this multidrug-resistant isolate.
- To understand the phylogenetic context of CTX-M-15-producing H. parainfluenzae.
Main Methods:
- Antimicrobial susceptibility testing using gradient strips and hydrolysis assays (β LACTA test).
- Whole-genome sequencing (Illumina and Oxford Nanopore) to analyze the blaCTX-M-15 genetic context.
- Phylogenetic analysis of H. parainfluenzae genomes from public databases.
Main Results:
- The isolate HP01 was extensively drug-resistant (XDR), susceptible only to carbapenems and rifampicin.
- HP01 harbored blaTEM-1, blaCTX-M-15, tet(M), catS, and mef(E)/mel genes, with resistance-associated amino acid substitutions.
- The blaCTX-M-15 gene was located on a Tn3-like transposon within a novel integrative and conjugative element (ICEHpaSLS) on the chromosome.
Conclusions:
- An extensively drug-resistant H. parainfluenzae isolate producing blaCTX-M-15 was identified from a urethral swab.
- The blaCTX-M-15 gene was integrated into an ICE structure, similar to other Spanish isolates, indicating potential transmission.
- The emergence of XDR H. parainfluenzae producing blaCTX-M-15 is a significant threat, requiring vigilant surveillance to prevent its dissemination.
