# Monoclonal outbreak caused by ceftazidime-avibactam resistant blaOXA-48-positive, carbapenem-resistant Klebsiella pneumoniae in an intensive care unit

## TL;DR

A study found a monoclonal outbreak of antibiotic-resistant Klebsiella pneumoniae in an ICU, highlighting the need for better infection control and surveillance.

## Contribution

The study identifies a clonal outbreak of ceftazidime-avibactam-resistant blaOXA-48-positive CRKP in an ICU setting.

## Key findings

- 15 blaOXA-48-positive CRKP isolates showed resistance to multiple antibiotics including CAZ-AVI and colistin.
- AP-PCR revealed five genotypes, with 73.3% clustering under genotype 1, indicating a monoclonal outbreak.
- Active surveillance and infection control measures are crucial to prevent spread of CAZ-AVI-resistant CRKP.

## Abstract

This study aimed to determine the ceftazidime-avibactam susceptibilities and clonal relationships of blaOXA-48-positive, carbapenem-resistant K. pneumaniae (CRKP) isolates.

Fifteen K. pneumaniae isolates from various clinical samples, determined as blaOXA-48-positive CRKP by VITEK 2 compact system and multiplex PCR, were included in the study. Colistin susceptibility of isolates was tested using the broth microdilution method. The Kirby-Bauer disk diffusion test was performed for CAZ-AVI susceptibility. Arbitrary primer sequence-based PCR (AP-PCR) was used to investigate genotypic similarity between the isolates.

All 15 blaOXA-48-positive CRKP isolates were resistant to meropenem, ertapenem, imipenem, amikacin, gentamicin, ciprofloxacin and levoflokxacin. Four of the CRKP isolates were susceptible to SXT and colistin. 73.3% (11/15) of the CRKP isolates were found to be resistant to CAZ-AVI. One of the 15 blaOXA-48-positive CRKP isolates was also a blaNDM carrier. AP-PCR revealed that 15 isolates showed five different genotypes. Eleven of the isolates were classified under genotype 1, leading to a clustering rate of 73.3%. Isolates in the genotype 1 group were defined as outbreak isolates. All but one of the genotype 1 outbreak isolates were resistant to all antibiotics studied, including CAZ-AVI and colistin.

This study evaluated an intensive care unit outbreak caused by a clone resistant to CAZ-AVI, which has been reported to have susceptibility rates of up to 100% in OXA-48-producing CRKP isolates and is suggested as first choice therapy. To prevent the spread of CAZ-AVI-resistant CRKP isolates, it is essential to conduct active surveillance studies in hospitals. Especially ICUs – where these strains are common – should be routinely screened. Infection control practices in general must also be tightened.