Epidemiological surveillance, virulence and public health significance of Listeria spp. from drinking water

Abstract

Epidemiological surveillance of drinking water from Punjab, India reported occurrence of Listeria spp. in 58.67% of Municipal Corporation (MC), 51.38% submersible pump and 12.5% hand pumps and Escherichia coli in 53.71% of MC, 29.16% submersible pump and none of samples from hand pumps. There was no positive correlation between the simultaneous occurrence of Listeria spp. and E. coli (P < 0.005; R2 = 0.89). Isolates were identified serologically and confirmed by polymerase chain reaction (PCR) amplification using specific primers targeting a 1200 bp fragment of the 16S rRNA gene. All isolates of Listeria spp. were haemolytic on 5% sheep blood agar and positive for congo dye uptake and showed multiple drug resistance, multiple antibiotic resistance (MAR) indices of 0.86 (> 0.2). One isolate of Listeria spp. was molecularly identified by sequencing of 16S rRNA gene, and its gene sequence was submitted to National Center for Biotechnology Information (NCBI) under accession no. JF798637. Using this isolate, histopathological studies were carried out and It caused significant histopathological and ultrastructural alterations in experimentally infected BALB/c mice. The conventional methods cannot predict the presence of these potentially enteropathogenic microorganisms in drinking water and hence represents a serious public health concern.

Key words: Epidemiological, Listeria spp., haemolytic, serologically histopathological, multiple antibiotic resistance (MAR).