Investigation of the Presence of New Delhi Metallo-Beta-Lactamase-1 (NDM-1) by PCR in Carbapenem-Resistant Gram-Negative Isolates

Abstract

Bacteria producing New Delhi metallo-beta-lactamase-1 (NDM-1) exhibit high level resistance to beta-lactams including carbapenems. This broad-spectrum resistance limits treatment options for infections caused by NDM-1 producers. NDM-1 was first isolated from an Indian patient in Sweden; since then, NDM-1 producing isolates have been identified in many countries including Turkey. In this study, we investigated the presence of NDM-1 by PCR method in various gram-negative isolates recovered from clinical specimens in tertiary care hospitals in Samsun, Turkey. A total of 210 carbapenem-resistant gramnegative isolates (132 Acinetobacter baumannii, 54 Pseudomonas aeruginosa, 5 Pseudomonas putida, 8 Enterobacter cloacae, 3 Enterobacter aerogenes, 3 Klebsiella pneumoniae, 2 Providencia rettgeri, 2 Escherichia coli and 1 Citrobacter freundii) were included in the study. Identification and antibiotic susceptibility testing of the isolates were performed by using Vitek-2 Compact (bioMerieux, France) and BD Phoenix (BD Diagnostic Systems, MD) automated systems. The results of antibiotic susceptibility testing were interpreted according to the CLSI recommendations. In our study, NDM-1 gene was not detected in any of the clinical isolates by PCR. There was only one case study that reported the presence of NDM-1 in clinical isolates from Turkey [Poirel L et al. Antimicrob Agents Chemother 2012;56:2784]. Our data, together with the others, indicated that the existence of NDM-1 in clinical isolates is not common in Turkey. However, since NDM-1 is a plasmid-encoded enzyme, there is always a risk of spread of this resistance through the bacterial strains in our country. Therefore, continuous surveillance and investigation of carbapenem-resistant isolates with resistance patterns suggestive of NDM-1 may enable to identify NDM-1 producing isolates. Meanwhile special care should be given on rational antibiotic use and establishment of appropriate infection control policies to prevent the spread of NDM-1 producers and other potential resistant strains.

Molecular Characterization of Carbapenem-Resistant Klebsiella pneumoniae Species Isolated From a Tertiary Hospital, Ankara, Turkey

“…Currently, a NDM-1 positive K. pneumoniae epidemic was described in a tertiary hospital and 2 of the isolates also harbored the blaOXA-48 (36). Parallel to the results of Turkey, the emergence of NDM-1 producers among K. pneumonae and other Enterobacteriaceae members is reported worldwide, especially from India and Middle East and Far East countries (37,38). Verona integron-encoded MBLs and IMPs are the most common MBLs worldwide especially in Greece, Taiwan, and Japan.…”

Phenotypic detection and molecular characterization of beta-lactamase genes among Citrobacter species in a tertiary care hospital

“…MBL E-test was found positive for 78.64% (81), followed by CDST in 54.6% (71), DDST in 53.8% (70), and MHT in 39.2% (51) Table 2. Among 91 Citrobacter koseri tested, carbapenem resistance was detected in 79.1% (72) isolates MBL E-test found positive for 52.74% (48) isolates, followed by CDST in 47.3% (43), DDST in 46.15% (42) and MHT in 28.57% (26) [Table 3].…”

“…Their lower frequency might be due to the sample size and geographical region or to timing of the studies as the prevalence of these resistance genes in increasing with time. [ 30 41 ] Emergence of bla NDM-1 producing Citrobacter isolates reported from Bangladesh,[ 42 ] Turkey,[ 43 ] Thailand,[ 44 ] France,[ 45 ] South Africa,[ 46 ] United Arab Emirates,[ 47 ] Canada,[ 48 49 ] and India. [ 50 ] We detected presence of bla NDM-1 in 55.30% (99/179) while bla VIM was present in 17.87% (32/179) of carbapenem resistant strains.…”

Evaluation of carbapenem resistance using phenotypic and genotypic techniques in Enterobacteriaceae isolates

“…In Turkey, molecular studies focusing on carbapenem resistance mechanisms are limited [ 8 , 12 ]. Some regional studies have shown an association between the OXA-48 gene and carbapenem resistance in gram-negative enteric bacilli [ 13 , 14 ].…”

“…From this isolated case, NDM-1 was identified as the first resistance gene detected from an international origin [ 14 ]. Yanik et al [ 12 ] conducted a study in Samsun-Turkey in which the carbapenemase enzyme was detected using the MHT technique in gram-negative strains resistant to at least one of the antibiotics (imipenem, meropenem or doripenem). PCR was performed to detect NDM-1, but no NDM-1 gene resistance was found in any of the 210 clinical isolates.…”