Detection of CTX-M-15 ESBL in XDR Haemophilus parainfluenzae from a urethral swab.

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 bla CTX-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 bla TEM-1, bla CTX-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 bla CTX-M-15 was carried by a Tn 3 -like transposon inserted into a novel integrative and conjugative element (ICE), ICE Hpa SLS, present on the chromosome and belonging to the ICE Hin1056 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 bla CTX-M-15 isolated from a urethral swab. The bla CTX-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 bla CTX-M-15 is a matter of great concern. Careful surveillance is required to prevent its spread. [ABSTRACT FROM AUTHOR]