Virulence-associated traits and in vitro biofilm-forming ability of Escherichia coli isolated from a major river traversing Northern India

Genomic analysis of phylogroup D Escherichia coli strains using novel de-novo reference-based guided assembly

Escherichia coli are highly diverse bacteria with different pathogenic types, serotypes and phylogenetic types/phylotypes. In recent years, infections with E. coli have increased worldwide and so has the emergence of antibiotic resistant strains. In the present study we have assembled, annotated and analysed genome sequences of three strains of the phylogroup D of E. coli. These strains were isolated from the river Yamuna, a prominent anthropogenic urban river of northern India. These strains showed varied antibiotic susceptibilities, one was susceptible to all the antibiotics tested except ampicillin while of the other two, one was multi-β-lactam resistant and the other was multi-drug resistant (resistant to multiple β-lactams, fluoroquinolones and kanamycin). The short-sequence reads were assembled into contigs using the de-novo approach and further, scaffolding of contigs was performed by using the best reference genome for a particular isolate which resulted in a significant increase in the N50 value of each assembly. The bioinformatics assembly approach used in this study could be easily applied to study other bacterial genomes.

Public health implications of plasmid-mediated quinolone and aminoglycoside resistance genes in Escherichia coli inhabiting a major anthropogenic river of India

Presence of antimicrobial resistance (AMR) genes in Escherichia coli inhabiting anthropogenic rivers is an important public health concern because plasmid-mediated AMR genes can easily spread to other pathogens by horizontal gene transfer. Besides β -lactams, quinolones and aminoglycosides are the major antibiotics against E. coli. In the present study, we have investigated the presence of plasmid-mediated quinolone resistance (PMQR) and aminoglycoside resistance genes in E. coli isolated from a major river of northern India. Our results revealed that majority of the strains were phenotypically susceptible for fluoroquinolones and some aminoglycosides like amikacin, netilmicin, tobramycin and gentamicin. However, 16.39% of the strains were resistant for streptomycin, 8.19% for kanamycin and 3.30% for gentamicin. Of the various PMQR genes investigated, only qnrS1 was present in 24.59% of the strains along with ISEcl2 . Aminoglycoside-resistance genes like strA-strB were found to be present in 16.39%, aphA1 in 8.19% and aacC 2 in only 3.30% of the strains. Though, no co-relation was observed between phenotypic resistance for fluorquinolones and presence of PMQR genes, phenotypic resistance for streptomycin, kanamycin and gentamicin exactly co-related with the presence of the genes strA-strB , aphA1 and aacC2 , respectively. Moreover, all the AMR genes discerned in aquatic E. coli were found to be situated on conjugative plasmids and, thus easily transferrable. Our study accentuates the importance of routine surveillance of urban rivers to curtail the spread of AMR genes in aquatic pathogens.

Assessment of the Presence of Resistance Genes Detected from the Environment and Selected Food Products in Benin

Gram-negative bacilli can spread from the environment and through food products. This study aimed to characterize ESBL production and virulence genes from multidrug-resistant Gram-negative bacilli isolated from specimen collected from the environment, kitchen, and food products. A total of 130 samples were collected at local markets in seven different communities in Benin (Abomey-Calavi, Ouidah, Bohicon, Abomey, Parakou, Djougou, and Grand-Popo). Samples were cultured on McConkey and ChromID^™ ESBL agar plates. The isolates were identified by the API 20E gallery. An antibiotic susceptibility test was carried out, and the detection of ESBL production and virulence-associated genes was carried out by Polymerase Chain Reaction (PCR). The data collected was coded and analyzed using GraphPad prism 7 software and Excel. The software R was used to calculate the correlation coefficient between the results of the detection of ESBL+ on agar and by the effect of the double synergy. The results showed that sixty-three (63) bacterial strains were isolated from the 130 samples, of which the dominant species was Chryseomonas luteola (10/63). The kitchen samples were the most contaminated with 36.50%. More than 40% of the isolates were resistant to at least three different classes of antibiotics. Also, blaSHV gene was detected in 33.33% (21/63) of the isolates and in all isolates of Pseudomonas aeruginosa (5/5%). 11.11% (7/63) of isolates were virulent with dominance of the fimH gene, especially with Escherichia coli (83.33%). The kitchen samples showed a high prevalence of ESBL-producing strains with fimH gene. This raises the problem of non-compliance with hygiene rules in community cooking and food handling.