Meta-analysis of the reduction of antibiotic-sensitive and antibiotic-resistant Escherichia coli as a result of low- and medium-pressure UV lamps.

It is vital that harmful bacteria are removed from water and wastewater treatment plants to prevent human/environmental exposure. This paper examines the log reduction of antibiotic-sensitive (AS) and antibiotic-resistant (AR) Escherichia coli (E. coli) as a result of low-pressure (LP) and medium-pressure (MP) UV lamps. A meta-analysis was performed and a mixed-effect model was created in which 303 data points on the log reduction of E. coli from UV treatment were collected. The results show that in order to achieve a 6 log reduction using an MP lamp, on average a UV level of 7.3 mJ/cm2 for AS E. coli and 7.5 mJ/cm2 for AR E. coli were required. Using an LP lamp, a UV level of 8.1 mJ/cm2 for AS E. coli and 8.4 mJ/cm2 for AR E. coli were required. The results show there is no significant difference between the inactivation of AR and AS E. coli at different UV levels. The model predicts that AR or AS E. coli will be inactivated at UV levels lower than the recommended UV operation conditions (40 mJ/cm2), but it is important to use this UV level to inactivate other harmful microorganisms.