Characterization of Carbapenemase-Producing Enterobacteriaceae from Patients in Amman,Jordan

Abstract

We sought to detect and determine the genetic diversity of carbapenemase-producing Enterobacteriaceae (CPE) isolated from clinical specimens in Amman, Jordan. From five hospitals, a total of 2,759 isolates had antimicrobial susceptibilities determined via Vitek II, of which 28 (1%) were carbapenem resistant. Species identifications were determined via matrix-assisted laser desorption ionization time-of-flight mass spectrometry and carbapenemase gene detection via real-time PCR indicated that 23 (82.1%) isolates were Klebsiella pneumoniae (OXA-48-like, n = 7; NDM, n = 14; OXA-48-like and NDM, n = 2), four (14.2%) were Enterobacter cloacae complex (NDM, n = 3 and VIM, n = 1), and one (3.5%) was Escherichia coli (NDM). Sequencing of carbapenemase gene amplicons from a subset of isolates identified bla_NDM-1, bla_OXA-48, and bla_VIM-4 alleles. Strain typing detected seven different K. pneumoniae variable number tandem repeat types, consistent with mostly sporadic occurrences along with limited clonal spread. E. cloacae complex isolates were diverse by pulsed-field gel electrophoresis, with a maximum relatedness of 70%. Plasmid restriction fragment length polymorphism (pRFLP) revealed four distinct profiles associated with NDM-encoding plasmids that were positive for replicons of the FII(K)/FIB or FIB incompatibility (Inc) groups via PCR-based replicon typing. OXA-48-encoding IncL/M plasmids differed by two pRFLP bands. The results show diverse CPE produce OXA-48 and NDM-1 enzymes in Jordan and that the carbapenemase genes are distributed on diverse plasmids in Jordanian hospitals, with some limited evidence for related clusters occurring, emphasizing the need for strict infection control measures.