The multidrug resistant Escherichia coli strains causes multiple clinical infections and has become a rising problem globally. The metallo-β-lactamases encoding genes are very severe in gram-negative bacteria especially E. coli. This study was aimed to evaluate the prevalence of MBLs among the clinical isolates of E. coli. A total of 65 E. coli isolates were collected from various clinical samples of Malaysian patients with bacterial infections. The conventional microbiological test was performed for isolation and identification of E. coli producing MBLs strains in this vicinity. Multidrug Resistance (MDR) of E. coli isolates were assessed using disk diffusion test. Phenotypic methods, as well as genotypic-PCR methods, were performed to detect the presence of metallo-β-lactamase resistance genes (blaIMP, blaVIM) in imipenem resistant strains. Out of 65 E. coli isolates, 42 isolates (57.3%) were MDR. The isolates from urine (19) produced significantly more MDR (10) isolates than other sources. Additionally, 19 (29.2%) imipenemresistant E. coli isolates contained 10 MBLs gene, 7(36.8%) isolates contained blaIMP and 3(15.7%) isolates contained blaVIM genes. This study revealed the significant occurrence of MBL producing E. coli isolates in clinical specimens and its association with health risk factors indicating an alarming situation in Malaysia. It demands an appropriate concern to avoid failure of treatments and infection control management.

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Background Melanin finds enormous applications in different industries for its unique photoprotective and anti-oxidant properties. Due to its emerging demand, scientific researchers are putting efforts to unravel more microorganisms with a potential of producing melanin on large scale. Hence, the present study was aimed at the isolation of extracellular melanin producing microorganisms from lime quarries of Karnataka, India. Besides this, the tyrosinase gene governing melanin synthesis in different organisms were compared in silico to understand its evolutionary aspects. Material and methods Melanin producing microorganisms were screened on tyrosine gelatin beef extract agar medium. Potential isolate was explored for submerged production of melanin in broth containing L-tyrosine. Melanin was characterized by UV-Vis spectroscopy, thin layer and high performance liquid chromatographic techniques. Antibacterial activity of melanin was performed by agar well assay. Comparative tyrosinase gene sequence analysis was performed by using Geneious 2021.1 trial version software. Results Pseudomonas otitidis DDB2 was found to be potential for melanin production. No antibacterial activity was exerted by the melanin against tested pathogens. The in silico studies showed that the common central domain of tyrosinase protein sequence of selected Pseudomonas sps. exhibited 100% identity with the common central domain of Homo sapiens tyrosinase (NP_000363.1). Conclusions Our study shows the production of melanin in good quantities by the isolate Pseudomonas otitidis DDB2 which can be explored for scale-up process. Since the melanin formed is of eumelanin type and the tyrosinase gene sequence of several Pseudomonas sp. showed relatedness to humans, this molecule may be further developed for sunscreen formulations.