Methods: In one month non-duplicate 74 paired rectal swabs were evaluated in the month of March 2015. The first swabs were analyzed using Xpert® Carba-R Assay in GX DX Systems; results were available for reading after 1h. The 2nd swabs were cultured on MacConkey agar plate on which a 10µg meropenem was placed and incubated for 18h. Isolates were identified by conventional methods and carbapenemase production confirmed by phenotypic and in-house PCR methods. Adequate positive and negative control strains were included in each run. All the internal controls performed weekly gave expected results. The carbapenemase genes of 5 known CRB analyzed were correctly detected.
Results: Samples of 9 out of 74 patients were Xpert® positive giving a point prevalence of 12.2%. Seven (9.5%) were culture positive; 3 CRE (2 Klebsiella and 1 Enterobacter spp.) and 4 Acinetobacter baumannii. Three of 4 A. baumannii were positive for blaVIM and the other blaOXA-48. The 2 K. pneumoniae were positive for blaNDM while the E. aerogenes carried blaVIM and blaNDM genes simultaneously. Confirmatory synergy test and in house PCR were in agreement with Xpert® results.
The assay demonstrated exquisite specificity and sensitivity. In addition it demonstrated a very high prevalence of CRB in the rectums of ICU patients, a critical finding crucial for proper decision to cohort or not patients at admission.
W. Jamal, None
L. Abdulaziz, None
A. Chadha, None