Open AccessPrincipal component analysis exploring the association between antibiotic resistance and heavy metal tolerance of plasmid-bearing sewage wastewater bacteria of clinical relevance
Author(s) -
Manisha Mandal,
Saumendra Nath Das,
Shyamapada Mandal
Publication year - 2020
Publication title -
access microbiology
Language(s) - English
Resource type - Journals
ISSN - 2516-8290
DOI - 10.1099/acmi.0.000095
Subject(s) - microbiology and biotechnology , bacteria , acinetobacter baumannii , antibiotic resistance , biology , enterococcus faecalis , kanamycin , plasmid , sewage , pseudomonas putida , antibiotics , pseudomonas aeruginosa , staphylococcus aureus , genetics , engineering , waste management , dna
This paper unravels the occurrence of plasmid-mediated antibiotic resistance in association with tolerance to heavy metals among clinically relevant bacteria isolated from sewage wastewater. The bacteria isolated were identified following conventional phenotypic and/or molecular methods, and were subjected to multiple-antibiotic resistance (MAR) profiling. The isolates were tested against the heavy metals Hg 2+ , Cd 2+ , Cr 2+ and Cu 2+ . SDS-PAGE and agarose gel electrophoretic analyses were performed, respectively, for the characterization of heavy metal stress protein and R-plasmid among the isolated bacteria. Principal component analysis was applied in determining bacterial resistance to antibiotics and heavy metals. Both lactose-fermenting ( Escherichia coli ) and non-fermenting ( Acinetobacter baumanniiandPseudomonas putida ) Gram-negative bacterial strains were procured, and showed MAR phenotypes with respect to three or more antibiotics, along with resistance to the heavy metals Hg 2+ , Cd 2+ , Cr 2+ and Cu 2+ . The Gram-positive bacteria,Enterococcus faecalis , isolated had ‘ampicillin–kanamycin–nalidixic acid’ resistance. The bacterial isolates had MAR indices of 0.3–0.9, indicating their ( E. faecalis ,E. coli ,A. baumanniiandP. putida ) origin from niches with high antibiotic pollution and human faecal contamination. The Gram-negative bacteria isolated contained a single plasmid (≈54 kb) conferring multiple antibiotic resistance, which was linked to heavy metal tolerance; the SDS-PAGE analysis demonstrated the expression of heavy metal stress proteins (≈59 and ≈10 kDa) in wastewater bacteria with a Cd 2+ stressor. The study results grant an insight into the co-occurrence of antibiotic resistance and heavy metal tolerance among clinically relevant bacteria in sewage wastewater, prompting an intense health impact over antibiotic usage.