Rushika Saksena1, Rajni Gaind1, Anju Sinha2, Charu Kothari1, Harish Chellani3, Manorama Deb1. 1. 1Department of Microbiology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India. 2. 2Department of Reproductive and Child Health, Indian council of Medical Research, New Delhi, India. 3. 3Department of Paediatrics, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India.
Abstract
BACKGROUND: The emergence of resistance amongst commensal flora is a serious threat to the community. However, there is paucity of data regarding antibiotic resistance in commensals in the absence of antibiotic pressure. METHODS: Altogether, 100 vaginally delivered antibiotic naïve exclusively breastfed neonates were selected. Stool samples collected on day (D)1, D21 and D60 of birth were cultured. Enterobacteriaceae isolates were screened for nalidixic acid (NA) and ciprofloxacin susceptibility as per CLSI guidelines. In 28 randomly selected neonates, isolates (n=92) resistant to NA and ciprofloxacin were characterized for the presence of plasmid-mediated quinolone resistance (PMQR) genes (qnrA, qnrB and qnrS, qepAand aac(6')-Ib-cr) and mutations in the quinolone resistance determining region (QRDR) of gyrA and parC genes by specific primers and confirmed by sequencing. RESULTS: A total of 343 Enterobacteriaceae were isolated from 100 neonates. On D1, 58 % of neonates were colonized with at least one Enterobacteriaceae predominantly E. coli. Overall resistance to NA was 60 % but ciprofloxacin resistance increased significantly from 15 % (14/96) on D1 to 38 % (50/132) on D60 (P-value <0.001). The predominant mechanism of fluoroquinolone resistance was mutation in gyrA (n=49) with or without PMQR. PMQR carrying isolates increased more than fivefold from D1 to D60. CONCLUSION: A high level of fluoroquinolone resistance in gut flora of antibiotic naïve and exclusively breastfed neonates suggests a rampant rise of resistance in the community. The source of resistance genes on D1 is probably maternal flora acquired at birth. High load of PMQR genes in commensal flora are a potential source of spread to pathogenic organisms.
BACKGROUND: The emergence of resistance amongst commensal flora is a serious threat to the community. However, there is paucity of data regarding antibiotic resistance in commensals in the absence of antibiotic pressure. METHODS: Altogether, 100 vaginally delivered antibiotic naïve exclusively breastfed neonates were selected. Stool samples collected on day (D)1, D21 and D60 of birth were cultured. Enterobacteriaceae isolates were screened for nalidixic acid (NA) and ciprofloxacin susceptibility as per CLSI guidelines. In 28 randomly selected neonates, isolates (n=92) resistant to NA and ciprofloxacin were characterized for the presence of plasmid-mediated quinolone resistance (PMQR) genes (qnrA, qnrB and qnrS, qepAand aac(6')-Ib-cr) and mutations in the quinolone resistance determining region (QRDR) of gyrA and parC genes by specific primers and confirmed by sequencing. RESULTS: A total of 343 Enterobacteriaceae were isolated from 100 neonates. On D1, 58 % of neonates were colonized with at least one Enterobacteriaceae predominantly E. coli. Overall resistance to NA was 60 % but ciprofloxacin resistance increased significantly from 15 % (14/96) on D1 to 38 % (50/132) on D60 (P-value <0.001). The predominant mechanism of fluoroquinolone resistance was mutation in gyrA (n=49) with or without PMQR. PMQR carrying isolates increased more than fivefold from D1 to D60. CONCLUSION: A high level of fluoroquinolone resistance in gut flora of antibiotic naïve and exclusively breastfed neonates suggests a rampant rise of resistance in the community. The source of resistance genes on D1 is probably maternal flora acquired at birth. High load of PMQR genes in commensal flora are a potential source of spread to pathogenic organisms.
Entities:
Keywords:
Fluoroquinolone resistance; gut flora; neonates; plasmid-mediated quinolone resistance
Authors: Veronika Tchesnokova; Matthew Radey; Sujay Chattopadhyay; Lydia Larson; Jamie Lee Weaver; Dagmara Kisiela; Evgeni V Sokurenko Journal: Proc Natl Acad Sci U S A Date: 2019-07-01 Impact factor: 11.205