Analysis of transmission-related third-generation cephalosporin-resistant Enterobacterales by electronic data mining and core genome multi-locus sequence typing.

BACKGROUND

To contain intra-hospital transmission of third-generation cephalosporin-resistant Enterobacterales (3GCR-E), contact isolation precautions are recommended.

AIM

To quantify transmissions of 3GCR Escherichia coli and 3GCR Klebsiella pneumoniae within a hospital.

METHODS

An automated outbreak detection system (AODS) was used to identify clusters (N≥2) of 3GCR Enterobacterales for the years 2016, 2018 and 2020. Clusters were defined by phenotypic agreement of microbiological results and spatial and temporal relationship. Core genome multi-locus sequence typing (cgMLST) was used to confirm whether the cluster isolates were transmitted between patients.

FINDINGS

A total of 4343 3GCR E. coli and 1377 K. pneumoniae isolates were analysed. Among the 3GCR E. coli isolates, the AODS identified 304 isolates as cluster isolates, the median cluster size was two (range: 2-5). The cgMLST analysis revealed that a total of 23 (7.5%) 3GCR E. coli cluster isolates were transmission-associated, of which 20 isolates (87%) were detected in intensive care patients. Among the 3GCR K. pneumoniae isolates, the AODS identified 73 isolates as cluster isolates, the median cluster size was two (range: 2-4). CgMLST revealed that 35 (48%) 3GCR K. pneumoniae cluster isolates were transmission associated, of which 27 isolates (77%) were detected in intensive care patients.

CONCLUSION

For 3GCR K. pneumoniae, cgMLST confirmed the AODS results more frequently than for 3GCR E. coli. Therefore, contact isolation precautions for 3GCR K. pneumoniae may be appropriate on intensive care units, but only in certain circumstances, such as outbreaks, for Enterobacterales with lower transmissibility, such as E. coli.