Globally, coastal waters have emerged into a pool of antibiotic resistance genes and multiple antibiotic resistant microorganisms, and pathogenicity of these resistant microorganisms in terms of serotypes and virulence genes has made the environment vulnerable. The current study underscores the presence of multiple antibiotic resistant pathogenic serotypes and pathotypes of Escherichia coli, the predominant faecal indicator bacteria (FIB), in surface water and sediment samples of famous recreational beaches (Juhu, Versova, Mahim, Dadar, and Girgaon) of Mumbai. Out of 65 faecal coliforms (FC) randomly selected, 38 isolates were biochemically characterized, serotyped (for 'O' antigen), antibiogram-phenotyped (for 22 antimicrobial agents), and genotyped by polymerase chain reaction (for virulence factors). These isolates belonged to 16 different serotypes (UT, O141, O2, O119, O120, O9, O35, O126, O91, O128, O87, O86, R, O101, O118, and O15) out of which UT (18.4%), O141 (15.7%), and O2 (13.1%) were predominant, indicating its remarkable diversity. Furthermore, the generated antibiogram profile revealed that 95% of these isolates were multiple antibiotic resistant. More than 60% of aminoglycoside-sensitive E. coli isolates exhibited resistance to penicillin, extended penicillin, quinolone, and cephalosporin classes of antibiotic while resistance to other antibiotics was comparatively less. Antibiotic resistance (AR) indexing indicated that these isolates may have rooted from a high-risk source of contamination. Preliminary findings revealed the presence of enterotoxin-encoding genes (stx1 and stx2 specific for enterohaemorrhagic E. coli and Shiga toxin-producing E. coli, heat-stable toxin enterotoxin specific for enterotoxigenic E. coli) in pathogenic serotypes. Thus, government authorities and environmental planners should create public awareness and adopt effective measures for coastal management to prevent serious health risks associated with these contaminated coastal waters.

The marine environment is open to large sources of toxic organic waste in the form of accidental oil spills. Therefore, it is important to study microbial degradation processes that help reduce the damage caused to the environment. Universally, oil spills produce enormous public anxiety and highlight the need for costeffective, indigenous and environmentally acceptable bioremediation technologies. In recent times, advanced remedial techniques have been opted, such as solidifying, skimming, controlled burning and bioremediation. The present study aimed to isolate crude oil-degrading marine bacteria from Vadinar coastal area of Gujarat, India. Among seven isolates, three potential bacterial strains were chosen for crude oil and petroleum hydrocarbon (PHC) degradation, which were analysed by UV spectrophotometric and fluorometric analysis. These bacterial cultures were verified by 16S rRNA gene sequencing and identified as Bacillus species. Phylogenetic analysis was carried out to confirm the evolutionary relationship with existing oil-degrading species. In the present study, drop collapse, oil spreading and emulsification assay were performed to detect biosurfactant production. Bacillus sp. NM1 KT354277 was capable of degrading 50% of PHCs at the end 72 h for one week under rotary incubation in ONR7a medium. Among the studied strains, Bacillus sp. NM3 KT354278 showed promising lipase activity, viz. 60.72 and 61.19 U ml -1 for 2% of olive oil and tributyrin respectively. Thus, the present study explores indigenous marine isolates that could be utilized as a potential alternative for oilspill remediation in future.

No abstract

No abstract