Implementation of Chromatic Super CAZ/AVI® medium for active surveillance of ceftazidime-avibactam resistance: preventing the loop from becoming a spiral

Gabriele Bianco; Matteo Boattini; Sara Comini; Alessio Leone; Alessandro Bondi; Teresa Zaccaria; Rossana Cavallo; Cristina Costa

doi:10.1007/s10096-022-04480-x

Implementation of Chromatic Super CAZ/AVI^® medium for active surveillance of ceftazidime-avibactam resistance: preventing the loop from becoming a spiral

Eur J Clin Microbiol Infect Dis. 2022 Sep;41(9):1165-1171. doi: 10.1007/s10096-022-04480-x. Epub 2022 Aug 6.

Authors

Gabriele Bianco¹, Matteo Boattini^{1

2}, Sara Comini³, Alessio Leone^{1

2}, Alessandro Bondi^{1

2}, Teresa Zaccaria¹, Rossana Cavallo^{1

2}, Cristina Costa^{1

2}

Affiliations

¹ Microbiology and Virology Unit, University Hospital Città Della Salute E Della Scienza Di Torino, Corso Bramante 88/90, 10126, Turin, Italy.
² Department of Public Health and Paediatrics, University of Torino, Turin, Italy.
³ Department of Public Health and Paediatrics, University of Torino, Turin, Italy. sara.comini@unito.it.

Abstract

Acquired resistance towards ceftazidime-avibactam (CAZ-AVI) is increasingly reported. Several mechanisms can be involved, but mutations in the Ω-loop region of β-lactamases are the most described. Herein, we assessed the implementation of Chromatic Super CAZ/AVI^® medium in rectal swab surveillance cultures in a geographic area with endemic distribution of KPC-producing Klebsiella pneumoniae. Routine rectal swabs collected from the intensive care unit (ICU) and non-ICU patients were screened for carbapenemase-producing Enterobacterales (CPE), carbapenem-resistant Gram-negative organisms (CR-GN) and CAZ-AVI-resistant organisms by Chromatic CRE and Super CAZ/AVI^® media. Among the 1839 patients screened, 146 (7.9%) were found to be colonized by one or more CPE and/or CR-GN isolates during hospitalization. Overall, among colonized patients the most common bacteria encountered were KPC-producing Enterobacterales (n = 60; 41.1%), carbapenem-resistant Pseudomonas aeruginosa (n = 41; 28.1%) and carbapenem-resistant A. baumannii (n = 34; 23.3%). Among patients colonized by KPC-producing Enterobacterales, thirty-five (58.3%) had CAZ-AVI-resistant strains. A 30.5% rate of faecal carriage of CAZ-AVI-resistant KPC-producing K. pneumoniae, substantially higher than that of susceptible isolates (2.8%), was observed in the COVID-19 ICU. Prevalence of faecal carriage of metallo-β-lactamase-producing organisms was low (0.5% and 0.2% for Enterobacterales and P. aeruginosa, respectively). Chromatic Super CAZ/AVI^® medium showed 100% sensitivity in detecting CPE or CR-GN isolates resistant to CAZ-AVI regardless of both MIC values and carbapenemase content. Specificity was 86.8%. The Chromatic Super CAZ/AVI^® medium might be implemented in rectal swab surveillance cultures for identification of patients carrying CAZ-AVI-resistant organisms to contain the spread of these difficult-to-treat pathogens.

Keywords: Carbapenemase; Carbapenemase detection; Ceftazidime-avibactam resistance; KPC; Outbreak; Surveillance culture.

MeSH terms

Anti-Bacterial Agents / pharmacology
Anti-Bacterial Agents / therapeutic use
Azabicyclo Compounds
COVID-19*
Carbapenems
Ceftazidime / pharmacology
Ceftazidime / therapeutic use
Cephalosporins
Drug Combinations
Humans
Klebsiella pneumoniae / genetics
Microbial Sensitivity Tests
Pseudomonas aeruginosa
Watchful Waiting*
beta-Lactamases / genetics

Substances

Anti-Bacterial Agents
Azabicyclo Compounds
Carbapenems
Cephalosporins
Drug Combinations
avibactam, ceftazidime drug combination
Ceftazidime
beta-Lactamases