Abundance of New Delhi Metallo-ß-Lactamase-Producing Acinetobacter, Escherichia, Proteus, and Pseudomonas spp. in Mahananda and Karala Rivers of India.

In this study, we report a high incidence of New Delhi metallo-ß-lactamase (NDM)-producing and ampicillin-catabolizing bacteria within carbapenem-resistant bacterial populations in the waters of two important rivers, Mahananda and Karala, bisecting two most populous towns, Siliguri and Jalpaiguri, respectively, in the northern West Bengal, India. Isolates producing NDM belonged to four genera, Acinetobacter, Escherichia, Proteus, and Pseudomonas; among which few were phylogenetically determined as putatively novel species. Class 1 integrons with the frequent presence of aadA and aac(6')-Ib gene cassettes in 50% of NDM-bearing isolates are indicative of possible selective pressures generated out of unregulated use of streptomycin, in agriculture practiced by the cultivators and tea planters living in locales drained by these two rivers, in their up- and downstream, and amikacin in the most crowded government-sponsored "sadar" and district hospitals of Siliguri and Jalpaiguri. NDM-delivering bacteria in rivers have genuine consequences for city inhabitants who are dependent on public water and sanitation facilities. Standard reconnaissance of antibiotic resistance, consolidating ecological sampling just as the assessment of clinical isolates, should be set up as a need.

Pandrug-resistant Pseudomonas sp. expresses New Delhi metallo-ß-lactamase-1 and consumes ampicillin as sole carbon source.

OBJECTIVES: This study aims to investigate ampicillin catabolism in a pandrug-resistant strain, Pseudomonas sp. MR 02 of P. putida lineage. METHODS: The characterization of carbapenem resistance was done following the standard protocol. The broth macrodilution method was used to determine the MIC values of antimicrobial agents both in the presence and in the absence of phenylalanine-ß-naphthylamide. High MIC values (>10 000 mg/L) of ampicillin led to speculation that it may serve as a growth substrate, and thus minimal medium was used to evaluate ampicillin as a nutrient. The growth of MR 02 was measured in minimal medium in the presence or absence of 0.4 mM EDTA, supplemented with ampicillin as sole carbon, nitrogen and energy source. RNA-seq was used to generate expression profiles of genes in ampicillin or glucose-grown cells. The blaNDM-1 gene of MR 02 was cloned in the pHSG398 vector and expressed in Escherichia coli DH5α. RESULTS: Phenotypic analysis along with genome sequence data identifies Pseudomonas sp. MR 02 as a pandrug-resistant strain. Transcriptome data has revealed that blaNDM-1 was among the top 50 differentially expressed genes in ampicillin grown cells compared to the glucose grown cells in the minimal medium. Heterologous expression of blaNDM-1 gene in E. coli DH5α enabled its growth and subsistence on ampicillin as the sole source of carbon and energy. DISCUSSION: The ability of a pandrug-resistant Pseudomonas sp. MR 02 to consume ampicillin for growth has a huge implication in the bioremediation of ß-lactam residues in the environment.

Draft Genome Sequence of a Novel Bacterium, Pseudomonas sp. Strain MR 02, Capable of Pyomelanin Production, Isolated from the Mahananda River at Siliguri, West Bengal, India.

The draft genome sequence of a novel strain, Pseudomonas sp. MR 02, a pyomelanin-producing bacterium isolated from the Mahananda River at Siliguri, West Bengal, India, is reported here. This strain has a genome size of 5.94 Mb, with an overall G+C content of 62.6%. The draft genome reports 5,799 genes (mean gene length, 923 bp), among which 5,503 are protein-coding genes, including the genes required for the catabolism of tyrosine or phenylalanine for the characteristic production of homogentisic acid (HGA). Excess HGA, on excretion, auto-oxidizes and polymerizes to form pyomelanin.