Microbiology, Fermentation & Biotechnology

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Browsing Microbiology, Fermentation & Biotechnology by Author "Badireddy, Madhusudana Rao"

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    A revisited two-step microtiter plate assay: Optimization of in vitro multiplicity of infection (MOI) for Coliphage and Vibriophage
    (Elsevier, 2021-08) Benala, Manikantha; Vaiyapuri, Murugadas; Sivam, Visnuvinayagam; Chalil George, Joshy; Raveendran, Karthika; George, Iris; Mothadaka, Mukteswar Prasad; Badireddy, Madhusudana Rao
    A 2-step microtiter plate assay was developed to simultaneously check wide values of MOIs of bacteriophages, ranging between MOI-0.0001 and MOI-10000 in the first step and optimize the most suitable MOI (lowest quantity of phage) for inhibiting the growth of the target bacteria in the second step. The results of the first step revealed that the effective MOI of coliphage-ɸ5 for controlling the growth of antimicrobial resistant (AMR) E. coli was between 4.36 and 43.6 for E.coli-EC-3; between 38.2 and 382 for E.coli-EC-7 and between 81.5 and 815 for E. coli-EC-11. The optimum MOI of coliphage-ɸ5 determined in the second step was 17.44, 191 and 326 for controlling the growth of E.coli-EC-3; E.coli-EC-7 and E.coli-EC-11, respectively. The effective MOI of vibriophageɸLV6 for controlling luminescent Vibrio harveyi in the first step was found to be between 18.3 and 183 and the optimum MOI as determined in the second step was 79. The sequential 2-step microtiter plate method yielded faster optimization of MOI and was economical compared to the conventional flask method. The measurement of OD values at 550 nm and 600 nm showed similar trend and replicate data from 5-wells and 3-wells yielded identical pattern indicating that the measuring absorbance data in 3-replicate wells at either OD550 or OD600 is sufficient to generate quantifiable phage lysis data. The 2-step microtiter plate assay finds application in phage therapy in human health care, agriculture and animal agriculture for determining the optimum MOIs for selected bacteriophages.
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    Antimicrobial resistance in Vibrios of shrimp aquaculture: Incidence, identification schemes, drivers and mitigation measures
    (Springer, 2021-01-18) Vaiyapuri, Murugadas; Pailla, Sravya; Badireddy, Madhusudana Rao; Pillai, Devika; C. N., Ravishankar; Mothadaka, Mukteswar Prasad
    Antimicrobial resistance (AMR) is a growing threat to the human, and animal population, worldwide. The antimicrobials used across all the sectors eventually pollute the aquatic environment and transform it into a hot spot for the emergence and spread of AMR. The bacteria under the genera Vibrio being ubiquitous to aquatic environment include a few species which are pathogenic to humans and aquatic animals. Despite extensive reviews available on AMR in human, terrestrial animal sectors and environment, there is a dearth of summarized information on AMR in Vibrios in shrimp aquaculture environment. In comparison to the human, and terrestrial animal health sector, a methodology for determination of AMR in vibrios associated with aquatic animals is still in its nascent stages and needs harmonization. The present review is centred on the AMR status in vibrios of shrimp farming environment and recent advances in the detection of resistance and discusses methodologies for AMR determination in vibrios and possible mitigation measures to control AMR spread.
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    Predominance of genetically diverse ESBL Escherichia coli identified in resistance mapping of Vembanad Lake, the largest fresh-cum-brackishwater lake of India
    (Springer, 2021-07-30) Vaiyapuri, Murugadas; Anna Sherin Pulithara Sebastian; George, Iris; Sandhya Soolamkandath Variem; Vasudevan, Radhakrishnan Nair; C.G., Joshy,; Badireddy, Madhusudana Rao; Sivam, Visnuvinayagam; Peeralil, Shaheer; Sanjeev, Devi; T., Muthulakshmi; Albert Moses, Sheela; C.N., Ravishankar; Mothadaka, Mukteswar Prasad
    Antimicrobial resistance (AMR) burden in Escherichia coli along the 90 km stretch of Vembanad Lake, Kerala, India, was assessed. Seventy-seven percent of water samples drawn from 35 different stations of the lake harbored E. coli. Antibiotic susceptibility test performed on 116 E. coli isolates revealed resistance to ≥ one antibiotic with 39 AMR profiles in 81%, multidrug resistance in 30%, and extended spectrum β-lactamase (ESBL) producers in 32%. Of all the 15 antibiotics tested, the probability of isolating cefotaxime-resistant E. coli was the highest (P ≤ 0.05) in the lake. Genetically diverse ESBL types, namely blaTEM-116, blaCTX-M -152, blaCTX-M -27, blaCTX-M -55, blaCTX-M-205, and blaSHV-27, were identified in the lake. This is probably the first report in India for the presence of blaCTX-M-205 (blaCTX-M-group 2) in the Vembanad Lake. ST11439 and single and double loci variants of ST443 and ST4533 were identified in multilocus sequence typing (MLST). Inc plasmids (B/O, F, W, I1, FIIA, HI1, P-1α, K/B, and N) identified in the lake evidences the resistance transmission potential of the E. coli isolated from the lake. Molecular typing (ERIC-PCR, MLST, and PBRT) delineated diverse E. coli, both between and within the sampling stations. Low multiple antibiotic resistance index (averageMAR< 0.2) indicates a lower risk of the lake to the human population, but the occurrence of genetically diverse ESBL E. coli in the Vembanad Lake signals health hazards and necessitates pragmatic control measures.