Occurrence of blaNDM Variants Among Enterobacteriaceae From a Neonatal Intensive Care Unit in a Northern India Hospital

Nayeem Ahmad; Shamsi Khalid; Syed M Ali; Asad U Khan

doi:10.3389/fmicb.2018.00407

Occurrence of bla_NDM Variants Among Enterobacteriaceae From a Neonatal Intensive Care Unit in a Northern India Hospital

Front Microbiol. 2018 Mar 7:9:407. doi: 10.3389/fmicb.2018.00407. eCollection 2018.

Authors

Nayeem Ahmad¹, Shamsi Khalid¹, Syed M Ali², Asad U Khan¹

Affiliations

¹ Interdisciplinary Biotechnology Unit, Medical Microbiology and Molecular Biology Lab, Aligarh Muslim University, Aligarh, India.
² Pediatrics Department, Jawaharlal Nehru Medical College, Aligarh Muslim University, Aligarh, India.

Abstract

Carbapenem-resistance among enterobacteriaceae has become a global health concern. The objective of this study was to understand NDM producing enterobacteriaceae and their genetic basis of resistance, spreading in neonatal intensive care unit. Carbapenem resistant NDM producing enterobacteriaceae isolates were recovered from rectal swab and blood sample of infants admitted in NICU. These were determined by using Carba-NP test. All isolates were identified using BD Phoenix^TM-100 and MICs were determined by broth microdilution method. The bla_NDM and associated resistant markers were checked by PCR followed by sequencing. Moreover, ERIC-PCR and genetic environment of bla_NDM gene were also performed for the analysis of clonal relationship and genetic surrounding of the strains. We characterized 44 isolates with bla_NDM variants in Escherichia coli (45.5%), Klebsiella pneumoniae (40.9%), Citrobacter freundii (4.5%), Citrobacter braakii (2.3%), Klebsiella oxytoca (2.3%), Enterobacter cloacae (2.3%), Enterobacter aerogenes (2.2%) from NICU, showing resistance against all antibiotics except colistin and polymixin B. ISAba125 and bleomycin gene were found surrounding all bla_NDM variants, besides class I integron on plasmid. (ERIC)-PCR data revealed non-clonal relatedness among most of the isolates. The transfer of resistant markers was confirmed by conjugation experiment. The PCR-based replicon typing was carried out using DNA of transconjugants. These isolates carried NDM-1 (20.45%), NDM-4 (36.36%), NDM-5 (38.64%), NDM-7 (4.55%), along with OXA, CMY, and SHV variants on conjugative plasmid of IncFIA, IncFIC, IncF, IncK, IncFIB, IncB/O, IncHI1, IncP, IncY, IncFIIA, IncI1, and IncN types. An increased number of carbapenem-resistant NDM producing enterobacteriaceae isolates recovered from NICU which is alarming signal for health workers and policy makers. Hence, it is utmost important to think about infection control measures.

Keywords: ERIC-PCR; Hospital; NDM; NICU; antibiotic resistance; carbapenemase; enterobacteriaceae.