Development of a Biocontrol Method Applying Bacteriophage-Containing Aerosol against Mycobacterium tuberculosis Using the Bacteriophage BTCU-1 and M. smegmatis as Models.

Chun-Chieh Tseng,Dan Chi Chang,Kai-Chih Chang

doi:10.3390/microorganisms7080237

Abstract

The application of bacteriophages for biocontrol has attracted increasing attention. Here, we applied ϕBTCU-1 as a model phage to develop a method for controlling Mycobacterium tuberculosis (MTB) by using a bacteriophage-containing aerosol in a chamber study. The soil-isolated ϕBTCU-1 can infect both MTB and Mycobacterium smegmatis. Our study used M. smegmatis as an MTB surrogate for safety reasons. Among all the evaluated air samplers, the Andersen impactor was chosen to evaluate the bactericidal efficiency of ϕBTCU-1 against M. smegmatis since the recovery rates of the Andersen impactor were 1.5 to 10.6 times higher than those of sampling filters. When airborne ϕBTCU-1 with the highest concentration of 109 PFU/m3 challenged M. smegmatis (105 CFU/m3) for 10 s, no M. smegmatis colony was recovered from the culture medium. For surface decontamination, no colony of M. smegmatis, which started at 1000 CFU/plate (63.6 cm2), was recovered when exposed to higher ϕBTCU-1 concentrations (>109 PFU/m3) for 60 min. Bacteriophages may be useful for reducing MTB contamination in the air or on hard surfaces. The method we have established suggests that the biocontrol method may be an alternative approach or may be combined with other disinfection methods to prevent MTB infection.

Highlights

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (MTB)
When M. smegmatis was grown to stationary phase for 48 h, microbe pellets were collected, aseptically washed with phosphate-buffered saline (PBS), and transferred to a centrifuge tube, which was capped and centrifuged (800× g, 5 min)
Since MTB can suspend and spread through the air, we investigated the efficiency of φBTCU-1 aerosols in reducing airborne M. smegmatis

Summary

Introduction

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (MTB). In Taiwan, the TB incidence (43.9/100,000) was 15 times higher than that in the United States (2.9/100,000) in 2016 [1,2]. When TB patients visit the hospital, a varied concentration range of MTB, from 1.9 to 5.2 × 104 copy/m3, can be detected by a real-time quantitative polymerase chain reaction during air sampling periods [3]. These concentrations do not represent the detected MTB that were viable because of the limitations of polymerase chain reaction. The control of MTB in a hospital environment is still an important issue worldwide

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