Lytics broadcasting system: A novel approach to disseminate bacteriophages for disinfection and biogenic hydrogen sulphide removal tested in synthetic sewage

Salim, Amrita; Shetty, K Sindhu; Febin, H.; Sameed, Nourin; Pal, Sanjay; Nair, Bipin G.; Madhavan, Ajith

doi:10.1016/j.rineng.2021.100314

Cited by 6 publications

(4 citation statements)

References 38 publications

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“…But the titre is dynamic since the device also accommodates the production host (6 × 10 9 CFU/mL) which results in infection and phage amplification. Passive diffusion from the BAR-LBS was previously reported to be 9.3 × 10 6 PFU/mL/h 19 , hence the efficiency of transfer from the device would maintain sufficient titre in wastewater. Nevertheless, the reduction in titre that was observed during the disinfection (when compared to the phage titre in the BAR-LBS) could hence be due to sequestration of phages or exhaustion of targets over a period of time.…”

Section: Discussionmentioning

confidence: 99%

Escherichia coli ST155 as a production-host of three different polyvalent phages and their characterisation with a prospect for wastewater disinfection

Salim

Madhavan

Subhash

et al. 2022

Sci Rep

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Bacteriophages are generally specific, and a cocktail of phages is needed to combat different bacterial targets. Their production usually requires pathogenic isolation hosts. We identified a novel strain, Escherichia coli ST155, that could serve as a production host for three different polyvalent phages (ϕPh_SE03, ϕPh_SD01, and ϕPh_EC01), thus superseding the use of individual isolation hosts. Upon propagation in E. coli ST155, the phages demonstrated differential intergeneric infectivity against Salmonella enterica, E. coli OP50, Shigella dysenteriae, E. coli MDR, and Acinetobacter baumannii. Phages were characterised based on morphology, latent period, burst size, the efficiency of plating, and restriction enzyme profile. Survival assay on Caenorhabditis elegans, the absence of Shiga toxin, and enterotoxigenic E. coli virulence genes indicated that E. coli ST155 could be non-pathogenic. Lack of antibiotic resistance and absence of functional prophages rendered the host suitable for environmental applications. As a proof-of-concept, phage ϕPh_SE03 was produced in ST155 by employing a unique Bacteriophage Amplification Reactor-Lytics Broadcasting System and was simultaneously disseminated into S. enterica augmented wastewater, which resulted in a 3-log reduction in 24 h. The study establishes the potential of E. coli ST155 as a phage production host thereby minimising the possibility of accidental release of pathogenic hosts into wastewater.

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Section: Discussionmentioning

confidence: 99%

Escherichia coli ST155 as a production-host of three different polyvalent phages and their characterisation with a prospect for wastewater disinfection

Salim

Madhavan

Subhash

et al. 2022

Sci Rep

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“…We have previously designed a biofilter with a probiotic Lactobacillus & bacteriophage cocktail, which could reduce the coliform count by 2-log orders of magnitude [64]. We have also designed a novel lytics broadcasting system (LBS), which dispenses bacteriophage and other cell free lytic agents that could reduce the target bacterial load by 3 to 4 log orders of magnitude [65]. We believe that Pseudomonas being a very invasive and dominant species in their respective ecosystem, it would reduce the load even further [66].…”

Section: Discussionmentioning

confidence: 99%

Aspergillus niger Culture Filtrate (ACF) Mediated Biocontrol of Enteric Pathogens in Wastewater

Subhash

Babu

Vijayakumar

et al. 2022

Water

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Robust control of pathogens in sewage facilitates safe reuse of wastewater rich in valuable nutrients for potential valorization through biological means. Aspergillus niger is widely reported in bioremediation of wastewater but studies on control of enteric pathogens in sewage are very sparse. So, this study aimed at exploring the antibacterial and nematicidal activity of A. niger culture filtrate (ACF). Antibacterial activity of ACF on enteric pathogens (Klebsiella pneumoniae, Pseudomonas aeruginosa, Vibrio cholerae, Salmonella enterica, Shigella dysenteriae, Escherichia coli, Staphylococcus aureus, Klebsiella variicola) was determined by spectrophotometric growth analysis, resazurin based viability assay and biofilm formation assay. ACF showed inhibition against all enteric pathogens except Pseudomonas aeruginosa. Nematicidal studies on Caenorhabditis elegans showed 85% egg hatch inhibition and 52% mortality of L1 larvae. Sewage treatment with ACF at 1:1 (v/v) showed 2–3 log reduction in coliforms, Klebsiella, Shigella, Salmonella, S. aureus and Vibrio except Pseudomonas, indicating significant alteration of complex microbial dynamics in wastewater. Application of ACF can potentially be used as a robust biocontrol strategy against infectious microbes in wastewater and subsequent valorization by cultivating beneficial Pseudomonas.

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“…The efficiency of the KBA media in surveillance of sewage for the presence of Klebsiella spp. was checked in synthetic sewage augmented with bacteria as described in the literature (Salim et al 2022 ) with modifications. Peptone, 160 mg; meat extract, 110 mg; anhydrous dipotassium hydrogen phosphate (K 2 HPO 4 ), 28 mg; sodium chloride (NaCl), 7 mg; calcium chloride dihydrate (CaCl 2 .2H 2 O), 4 mg; urea 30 mg; and magnesium sulphate heptahydrate (MgSO 4 .7H 2 0), 2 mg were added to 1 L water and autoclaved.…”

Section: Methodsmentioning

confidence: 99%

“…Peptone, 160 mg; meat extract, 110 mg; anhydrous dipotassium hydrogen phosphate (K 2 HPO 4 ), 28 mg; sodium chloride (NaCl), 7 mg; calcium chloride dihydrate (CaCl 2 .2H 2 O), 4 mg; urea 30 mg; and magnesium sulphate heptahydrate (MgSO 4 .7H 2 0), 2 mg were added to 1 L water and autoclaved. Chemical characteristics of the synthetic sewage were estimated as per the Indian Standard 3025 (IS 3025) (IS 3025 of Indian Standards Part 11, IS 3025 Part 44, IS 3025 Part 38, IS 3025 Part 16), as reported in the literature from the laboratory of the authors (Salim et al 2022 ). Synthetic sewage was augmented with the following cultures at an OD of 0.1 each, K. pneumoniae , K. quasipneumoniae , K. aerogenes , E. coli ST155, B. clausii , A. baumanii , S. enterica , P. vulgaris , V. cholerae , Shigella spp., MDR strains K. pneumoniae OF9168, K. pneumoniae K2, K. pneumoniae K3, K. pneumoniae K4, K. pneumoniae K5, and K. pneumoniae U498.…”

Section: Methodsmentioning

confidence: 99%

A novel and improved selective media for the isolation and enumeration of Klebsiella species

Prasad

Shetty

Nair

et al. 2022

Appl Microbiol Biotechnol

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Bacterial pathogens are fostered in and transmitted through wastewater. Hence, monitoring their impact on sanitation and hygiene is imperative. As part of the monitoring process, culture-based methodologies are primarily used, which centre on the use of selective and differential media. Media available today are, at best, difficult to formulate and, at worst, prohibitively expensive. To address this lacuna, the study proposes a selective and differential medium for Klebsiella spp. Klebsiella blue agar (KBA) is completely selective against selected gram-positive bacteria (Bacillus spp., Staphylococcus aureus) and a few gram-negative bacteria (Acinetobacter baumanii, Serratia marcescens). On the other hand, it supports the growth of the chosen members of the Klebsiella pneumoniae species-complex with a characteristic green colouration. Methylene blue, tryptophan, and bile salt make up the selective components of KBA. Moreover, methylene blue, 0.6% NaCl, and glycerol render it differential. KBA was more selective than HiCrome™ Klebsiella Selective Agar Base (KSA) in replica plating experiments. KBA promoted only 157 CFUs against 209 CFUs in KSA when stamped with 253 CFUs grown on LB. The colonies so isolated were predominantly Klebsiella spp., on identification through colony polymerase chain reaction. Moreover, the differential nature of KBA distinguished Klebsiella aerogenes from other species. On the contrary, KSA lodged colonies indistinguishable from each other and Klebsiella spp. Due to its ease of formulation, high selectivity, differential nature, and cost-effective composition, KBA is a viable option for the routine culture of Klebsiella spp. in environmental and clinical settings. Key points • Formulated a novel selective and differential media for Klebsiella spp., named Klebsiella Blue agar • Facile formulation methodology • Can be employed to isolate Klebsiella spp. from complex sources such as wastewater

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Lytics broadcasting system: A novel approach to disseminate bacteriophages for disinfection and biogenic hydrogen sulphide removal tested in synthetic sewage

Cited by 6 publications

References 38 publications

Escherichia coli ST155 as a production-host of three different polyvalent phages and their characterisation with a prospect for wastewater disinfection

Escherichia coli ST155 as a production-host of three different polyvalent phages and their characterisation with a prospect for wastewater disinfection

Aspergillus niger Culture Filtrate (ACF) Mediated Biocontrol of Enteric Pathogens in Wastewater

A novel and improved selective media for the isolation and enumeration of Klebsiella species

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