Isolation and identification of arsenic resistant bacteria: a tool for bioremediation of arsenic toxicity

Arsenic (As), a toxic element, has impacted life since early Earth. Thus, microorganisms have evolved many As resistance and tolerance mechanisms to improve their survival outcomes given As exposure. We isolated As resistant bacteria from Centralia, PA, the site of an underground coal seam fire that has been burning since 1962. From a 57.4°C soil collected from a vent above the fire, we isolated 25 unique aerobic arsenic resistant bacteria spanning six genera. We examined their diversity, resistance gene content, transformation abilities, inhibitory concentrations, and growth phenotypes. Although As concentrations were low at the time of soil collection (2.58 ppm), isolates had high minimum inhibitory concentrations (MICs) of arsenate and arsenite (>300 mM and 20 mM respectively), and most isolates were capable of arsenate reduction. We screened isolates (PCR and sequencing) using 12 published primer sets for six As resistance genes (AsRG). Genes encoding arsenate reductase (arsC) and arsenite efflux pumps (arsB, ACR3(2)) were present, and phylogenetic incongruence between 16S rRNA genes and AsRG provided evidence for horizontal gene transfer. A detailed investigation of differences in isolate growth phenotypes across As concentrations (lag time to exponential growth, maximum growth rate, and maximum OD590) showed a relationship with taxonomy, providing information that could help to predict an isolate’s performance given arsenic exposure in situ. Our results suggest that considering taxonomically-linked tolerance and potential for resistance transferability from the rare biosphere will inform strategies for microbiological management and remediation of environmental As and contribute to a larger consideration of As-exposed microbial ecology.

Download Full-text

Analysis of River Water Along Klang Valley to Evaluate the Prevalence of Antibiotics Resistant Strains within Urbanized Areas of Selangor, Malaysia

Proceedings International ◽

10.33263/proceedings21.059059 ◽

2020 ◽

Vol 2 (1) ◽

pp. 59

Keyword(s):

River Water ◽

Antibiotic Sensitivity ◽

Most Probable Number ◽

Resistant Bacteria ◽

Minimal Bactericidal Concentration ◽

Isolation And Identification ◽

Antibiotic Resistant ◽

Probable Number ◽

Antibiotic Sensitivity Test ◽

Klang Valley

The determination of antibiotic-resistant bacteria in Klang river water in Klang valley is performed as the river exposed to various environments. The analysis is performed through enumeration, isolation, and identification process. The water samples were obtained from the origin of the river, housing region, and hospital region. The coliforms obtained through enumeration and identification was then used to determine antibiotic sensitivity, minimum inhibitory concentration (MIC), and minimal bactericidal concentration (MBC). The level of coliforms was indicated through the most probable number (MPN), which 70 MPN per 100 ml of river water in the origin of the river while housing and hospital regions showed more than 1600 MPN per 100 ml of river water. The results obtained from the antibiotic sensitivity test showed that the degree of resistance of coliforms is varied in different regions. The zone of inhibition to ampicillin and tetracyclin for coliforms in housing regions is 20 mm, while the coliforms in the hospital region are 6 mm and 7 mm, respectively. The overall results showed that the level of coliforms and the antibiotic sensitivity of coliforms are different in various regions. The coliforms in the hospital region are more resistant to antibiotics compared to the housing region.

Download Full-text

Bactericidal Activity, Isolation and Identification of Most Active Compound from 20 Plants used in Traditional Mexican Medicine Against Multidrug-Resistant Bacteria

International Journal of Pharmacology ◽

10.3923/ijp.2018.203.214 ◽

2018 ◽

Vol 14 (2) ◽

pp. 203-214

Author(s):

C. Rivas-Mora ◽

V.M. Rivas-Gali ◽

J. Rodriguez- ◽

S.A. Galindo-Ro ◽

C. Leos-Rivas ◽

...

Keyword(s):

Bactericidal Activity ◽

Active Compound ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

Isolation And Identification ◽

Multidrug Resistant Bacteria

Download Full-text

Isolation and Identification of Resistant Bacteria from Petroleum Producing Vicinity by Gene Amplification and Sequencing

Biotechnology Journal International ◽

10.9734/bji/2021/v25i330139 ◽

2021 ◽

pp. 1-8

Author(s):

O. Aleruchi ◽

O. Obire

Keyword(s):

16S Rrna ◽

Phylogenetic Study ◽

Resistant Bacteria ◽

Rrna Gene ◽

Bacterial Isolates ◽

Antibiotic Resistant Bacteria ◽

Isolation And Identification ◽

Antibiotic Resistant ◽

Disinfection Process ◽

Adaptive Mechanisms

This investigation focuses on molecular identification of antibiotic resistant bacteria isolated from petroleum producing vicinity using 16S rRNA sequencing based technique. The bacterial 16s rRNA gene sequences were amplified using polymerase chain reaction, sequenced, characterized and compared by using primers which has been compared to national center for biotechnology information (NCBI) sequence database. The presence of the plasmid mediated antibiotic resistance determinants CTX-M and QNRB genes in the bacterial isolates were analyzed. A total of four bacterial isolates that were resistant to all the antibiotic agents used were identified molecularly. The BLAST results showed 100 % similarity and phylogenetic study indicated that the genes were evolutionarily related to Morganella morganii, Pseudomonas xiamenensis, Chryseobacterium cucumeris and Staphylococcus sp., respectively. The genes obtained were submitted to the NCBI gene bank and were assigned accession number; MN094330, MN094331, MN094332 and MN094333, respectively. CTX-M and QNRB genes were however absent in the bacterial isolates. The result identified some peculiar abilities of the bacterial isolates to be resistant to antibiotics and suggests a correlation with resistance and hydrocarbon utilizing bacteria. The level of resistance could be as a result of the disinfection process during wastewater treatment procedure or the same adaptive mechanisms possessed by the isolates to control the hydrocarbon concentration in their cell. The study also clearly indicates that these wastewaters, when discharged into the environment directly may pose a risk for the spread of antibiotic resistant bacteria.

Download Full-text