Environmental contamination with carbapenem resistant in healthcare settings in Fiji: a potential source of infection.

INTRODUCTION

There are multiple ongoing outbreaks of carbapenem resistant (CR) infection in Fiji's hospitals. CR is able to colonize and persist on various hospital surfaces for extended periods. We conducted a study to understand the extent of hospital environmental contamination and phylogenetic links with clinical isolates.

METHODS

Swabs were collected from high-touch surfaces at Colonial War Memorial Hospital (CWMH) September 2021 and December 2022; Lautoka Hospital (LTKH) August 2022; and Labasa Hospital (LBSH) November 2022. All bacterial isolates were identified, and antimicrobial susceptibility testing (AST) performed; isolates resistant to carbapenems and producing a carbapenemase underwent whole genome sequencing. Comparison was made to clinical isolates obtained from CWMH in 2016-2017 and 2019-2021 and from LTKH and LBSH from 2020-2021.

RESULTS

From the 180 environmental samples collected, ten (5.6%) CR were isolated; no other carbapenem-resistant gram-negative organisms were isolated. Seven (70%) of the CR were isolated from CWMH and three (30%) from LTKH; no CR were isolated from LBSH. Of the seven CWMH CR, two were sequence type 2 (ST2), three ST25, and two ST499. All LTKH isolates were ST499. The two environmental CR ST2 isolates were closely genetically linked to isolates obtained from patients in CWMH, LTKH, and LBSH 2020-2021. Similarly, the three environmental CR ST25 isolates were closely genetically linked to isolates obtained from patients admitted to CWMH in 2019-2021 and LBSH in 2020. The environmental CR ST499 isolates represented two distinct clones, with clone 1 comprising two genetically identical isolates from CWMH and clone 2 the three isolates from LTKH. Although no genetic linkages were observed when comparing environmental ST499 isolates to those from CWMH patients in 2020-2021, both clone 1 isolates were genetically identical to an isolate obtained from a patient admitted during the sampling period.

CONCLUSION

Our study highlights the contamination of high-touch surfaces within Fiji hospitals with CR, suggesting that these may serve as important sources for CR. Phylogenetic linkages to CR isolated from patients since 2019 underscores the persistence of this resistant pathogen in hospital settings and the ongoing risk for hospital-acquired infections.