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. 2023 Sep;27(9):655-662.
doi: 10.5005/jp-journals-10071-24533.

Xpert Carba-R Assay on Flagged Blood Culture Samples: Clinical Utility in Intensive Care Unit Patients with Bacteremia Caused by Enterobacteriaceae

Surendran Rajendran  1 , Ram Gopalakrishnan  1 , Anil Tarigopula  2 , D Suresh Kumar  1 , P Senthur Nambi  1 , Nandini Sethuraman  3 , Chitra Chandran  4 , Nagarajan Ramakrishnan  5 , V Ramasubramanian  1
Affiliations

Xpert Carba-R Assay on Flagged Blood Culture Samples: Clinical Utility in Intensive Care Unit Patients with Bacteremia Caused by Enterobacteriaceae

Surendran Rajendran et al. Indian J Crit Care Med. 2023 Sep.

Abstract

Introduction and background: Rapid molecular diagnostics to predict carbapenem resistance well before the availability of routine drug sensitivity testing (DST) can serve as an antimicrobial stewardship tool in the context of high rates of Carbapenem-resistant Enterobacteriaceae (CRE).

Materials and methods: A retrospective observational study of patients more than 18 years of age on whom Xpert Carba-R (FDA approved for rectal swab specimen) was done on gram-negative bacteria (GNB) flagged blood culture samples, in an Indian intensive care unit between January 2015 and November 2018. We analyzed the performance of Xpert Carba-R in comparison with routine DST.

Results: A total of 164 GNBs were isolated from 160 patients. Klebsiella pneumoniae and Escherichia coli were the predominant isolates. Carba-R was positive in 35.36% of samples and 45.34% were carbapenem-resistant (CR) on routine DST. The distribution of the CR gene was: Oxacillinase (OXA) (50%), NDM (32.7%) followed by OXA and NDM co-expression (15.51%). The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value, and negative predictive value of Carba-R were 90.74, 93.15, 13.25, 0.10, 83.58 and 96.31% for Enterobacteriaceae. The median time to obtain the Carba-R report was 30 hours 34 minutes vs 74 hours and 20 minutes for routine DST. Based on the Carba-R report, 9.72% of patients had escalation and 27.08% had de-escalation of antibiotics.

Conclusion: Xpert Carba-R serves as a rapid diagnostic tool for predicting carbapenem resistance in intensive care unit patients with bacteremia caused by Enterobacteriaceae.

How to cite this article: Rajendran S, Gopalakrishnan R, Tarigopula A, Kumar DS, Nambi PS, Sethuraman N, et al. Xpert Carba-R Assay on Flagged Blood Culture Samples: Clinical Utility in Intensive Care Unit Patients with Bacteremia Caused by Enterobacteriaceae. Indian J Crit Care Med 2023;27(9):655-662.

Keywords: Antimicrobial stewardship; Carbapenem-resistant enterobacteriaceae; Carbapenemase detection; Gram-negative resistance; Novel diagnostics for antimicrobial resistance; Rapid molecular diagnostics; Xpert Carba-R assay.

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Conflict of interest statement

Source of support: Nil Conflict of interest: None

Figures

Fig. 1
Fig. 1
Comparison of Carba-R and routine drug susceptibility testing
Fig. 2
Fig. 2
Distribution of carbapenem-resistant genes in the study population
Fig. 3
Fig. 3
Performance of Carba-R test in comparison with routine susceptibility testing
Fig. 4
Fig. 4
Suggested workflow with Carba-R
See this image and copyright information in PMC

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References

    1. Marston HD, Dixon DM, Knisely JM, Palmore TN, Fauci AS. Antimicrobial resistance. JAMA. 2016;316(11):1193–1204. doi: 10.1001/jama.2016.11764. - DOI - PubMed
    1. Global antimicrobial resistance surveillance system (GLASS) report: Early implementation 2017–2018. Geneva: World Health Organization; 2018. Available at: https://www.who.int/publications/i/item/9789241515061.
    1. Patel G, Bonomo RA. “Stormy waters ahead”: Global emergence of carbapenemases. Front Microbiol. 2013;4:1–17. doi: 10.3389/fmicb.2013.00048. - DOI - PMC - PubMed
    1. Zak-Doron Y, Dishon Benattar Y, Pfeffer I, Daikos G, Skiada A, Antoniadou A, et al. The association between empirical antibiotic treatment and mortality in severe infections caused by carbapenem-resistant gram-negative bacteria: A prospective study. Clin Infect Dis. 2018;67(12):1815–1823. doi: 10.1093/cid/ciy371. - DOI - PubMed
    1. Ferrer R, Martin-Loeches I, Phillips G, Osborn TM, Townsend S, Dellinger RP, et al. Empiric antibiotic treatment reduces mortality in severe sepsis and septic shock from the first hour: Results from a guideline-based performance improvement program. Crit Care Med. 2014;42(8):1749–1755. doi: 10.1097/CCM.0000000000000330. - DOI - PubMed