Sewage treatment effluents in Delhi: A key contributor of β-lactam resistant bacteria and genes to the environment. (December 2017)

• Record Type: Journal Article
• Authors: Lamba, Manisha; Ahammad, Shaikh Ziauddin
• Is Part Of: Chemosphere. Volume 188(2017)
• Page Start: 249
• Page End: 256
• Publication Date: 2017-12
• Subjects: Sewage treatment plant -- Antibiotic resistance -- β-lactams -- Proliferation; AR Antibiotic resistance -- ESBL Extended spectrum β-lactam -- KPC Carbapenem -- ARB Antibiotic resistant bacteria -- ARG Antibiotic resistant gene -- TC Total coliform -- FC Faecal coliform -- STP Sewage treatment plant -- PST Primary settling tank -- FST Final settling tank -- AD Anaerobic digester -- PS Sludge collected from PST -- FS Sludge collected from FST -- ADS Sludge collected from AD -- ASP Activated sludge process -- PBS Phosphate buffer solution -- DO Dissolved oxygen -- TDS Total dissolved solids -- COD Chemical oxygen demand -- BOD Biological oxygen demand -- WHO World health organization -- MLD Million litres per day -- MGD Million gallons per day; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2017.08.133
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Rapid emergence of antibiotic resistance (AR) in developing countries is posing a greater health risk and increasing the global disease burden. Lack of access to safe drinking water, poor sanitation and inadequate sewage treatment facilities in these countries are fueling the problem associated with emergence of AR. Rapid proliferation of AR mediated by treated and untreated discharges from sewage treatment plants (STPs) is a prime public health concern. This study aims to understand the occurrence, fate, and routes of proliferation of carbapenem (KPC) and extended spectrum β-lactam (ESBL) resistant bacteria, and selected resistant genes in the samples collected from different unit operations in 12 STPs in New Delhi over two seasons. Strong correlation observed between faecal coliform levels and KPC (R = 0.95, p = 0.005, n = 60) and ESBL (R = 0.94, p = 0.004, n = 60) resistant bacteria levels indicates possible association of resistant bacteria with faecal matter. Different unit operations in STPs proved inefficient in treating resistant bacteria and genes present in the wastewater. However, inclusion of tertiary treatment (chlorination) unit and anaerobic digester in the present STPs resulted in better removal of AR. Significant correlations between antibiotic resistant genes (ARGs) and integron levels indicates a potential for higher rate of AR proliferation in the environment. Microbial culturing indicated the presence of clinically significant drug-resistant pathogens such as Escherichia coli, Pseudomonas putida, Pseudomonas aeruginosa, Enterobacter cloacae, Klebsiella pneumoniae, Klebsiella oxytoca, Acinetobacter baumannii, Shigella dysentery and Aeromonas caviae in the STP effluents. The emergence and spread of resistant bacteria through STP effluents poses exposure risk for the residents of the city. Graphical abstract: Highlights: Presence of high levels of antibiotic resistance (ARB and ARGs) in STP effluents in New Delhi. Significant correlations between ARB and FC as well as ARGs and integron genes were observed. High abundance of carbapenem resistant Escherichia coli and Pseudomonas aeruginosa in the STP effluents. STP having chlorination unit and anaerobic digester performed better in treating ARB and ARGs.