Epidemiology of carbapenemase-producing Klebsiella pneumoniae in northern Portugal: Predominance of KPC-2 and OXA-48.

OBJECTIVES

To provide, for the first time, data on the molecular epidemiology of carbapenemase-producing Klebsiella pneumoniae clinical isolates from the northern region of Portugal (Trás-os-Montes and Alto Douro).

METHODS

A total of 106 carbapenemase-producing K. pneumoniae isolates recovered from clinical samples and rectal swabs between January 2018 and March 2019 were included in this study. All isolates were characterized by antimicrobial susceptibility, identification of resistance determinants, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and plasmid analysis.

RESULTS

The most common carbapenemase identified was KPC-2 (91%), followed by OXA-48 (9%). The bla gene was carried onto IncN (60%) and IncF (40%) plasmid types, whereas the bla gene was mainly located on the IncL (90%) incompatibility group. Molecular characterization distributed the 106 isolates into 29 PFGE types and 21 sequence types (STs), but three clones included 50% of the isolates: PFGE A-ST147-KPC-2 (29%), B-ST15-KPC-2 (15%), and C-ST11-OXA-48 (6%). Antimicrobial resistance rates were the following: ciprofloxacin (76%), trimethoprim-sulfamethoxazole (75%), tobramycin (62%), gentamicin (34%), amikacin (25%), tigecycline (21%), fosfomycin (10%), and colistin (7%). None of the colistin-resistant isolates harboured mcr genes. All isolates remained susceptible to ceftazidime/avibactam, but 10% presented elevated MICs (3 and 4mg/L).

CONCLUSIONS

KPC-2 was the predominant carbapenemase among K. pneumoniae isolates currently circulating at this hospital from northern Portugal, followed by OXA-48. These data contrast with those obtained from the rest of the country, where KPC-3 predominates. This study showed a polyclonal structure of KPC-2-producing K. pneumoniae isolates with a predominance of the ST147 and ST15 clones.