EXPERIMENTAL COMPARISON OF THE AEROSOL METHOD OF DISINFECTION OF AIR AND SURFACES CONTAMINATED BY M. TUBERCULOSIS

The objective of the study: to analyze efficiency of an aerosol method of M. tuberculosis deactivation in the air and on surfaces versus the conventional methods of the disinfectants' application.

Subjects and Methods. The article describes the evaluation of efficiency of the aerosol method of M. tuberculosis, H37Rv strain, deactivation on surfaces (tested objects made of linoleum) and in the air using the disinfectant of Green Dez based on chlorine dioxide versus deactivation through wiping and irrigation.

The efficiency of disinfectant was tested by the device of 099С А4224 manufactured by Glas-Col, USA, using the air sampler of PU-1B, Russia.

The Mobile Hygienic Center (MNC), Russia, was used for application of the disinfectant, wiping and irrigation was done using the disperser of Avtomaks AO-2, Russia.

The bacterial aerosol was generated in the Glass-Col chamber with the concentration 5 ± 2.5 × 102 CFU/cm3, by spraying the suspension of M. tuberculosis, H37Rv strain. After that, the disinfectant spray was supplied to the chamber, where linoleum objects were placed horizontally on a variety of surfaces. In order to evaluate efficiency of surface treatment by wiping, the test objects were wiped with a tissue, soaked with the solution of Green Dez, based on consumption of 100-150 ml/m2. In 15, 30 and 60 minutes, the samples of inactivated M. tuberculosis aerosol were collected using an aspirator, chambers with test objects were closed and placed in the vent hood. To monitor efficiency of disinfection of the test object surfaces, the rinse blanks were done by wiping the surface with a sterile gauze wad, soaked with 0.5% of sodium thiosulfate solution.

The samples of deactivated aerosol and rinse blanks from the surfaces of test objects were put into Petri dishes with Middlebrook 7H11 medium. The cultures were incubated in the thermostat at the temperature of 37 ± 1° C for 10-21 days, and the number of colonies was counted.

Sterile water was used instead of disinfectant for control tests treating the tests objects contaminated in the same manner.

Results. The good disinfection properties of Green Dez aerosol were proved during the simulation of M. tuberculosis, H37Rv strain, disinfection on the surfaces and in the air.

The efficiency analysis of the aerosol method of disinfection proved the reduction of disinfectant consumption by 4-5 times versus wiping and irrigation, due to this the aerosol treatment can be regarded as a safer and more environmentally friendly method.

The finely dispersed disinfectant aerosol, produced by MNC, effectively decontaminated the whole space, including the remote and hard-to-reach places. Full automation of disinfection implies no human presence providing high safety of disinfection. 

1. Vasilyeva I.A. Strategy for TB control services development in the Russian Federation. X S"ezd Rossiyskogo obschestva ftiziatrov Аktualnye voprosy protivotuberkuleznoy pomoschi v Rossiyskoy Federatsii. [The Xth Meeting of the Russian Society of Phthisiologists on Actual Issues of TB Care in the Russian Federation]. may 26-28, 2015, Voronezh, pp. 34. Available at: http://roftb. ru/netcat_files/doks2015/2003.pdf.

2. Dezinfektologiya. Metody laboratornykh issledovaniy i ispytaniy dezinfektsionnykh sredstv dlya otsenki ikh effektivnosti i bezopasnosti. Rukovodstvo R 4.2.2643-10. 3.5. [Disinfectology. Methods for laboratory testing of disinfectants in order to evaluate efficiency and safety. Guidelines Р 4.2.2643-10. 3.5.] Approved by Rospotrebnadzor as of 01.06.2010.

3. Kuzmina S.G., Pakhtina N.V. New technologies for overall cleaning of surgery units and wards with high epidemiological risks. Glavnaya Meditsinskaya Sestra, 2005, no. 4, pp. 96-99. (In Russ.).

4. Metodicheskie rekomendatsii Poryadok raboty s aerozolyami mikroorganizmov s tselyu proverki bakteritsidnoy effektivnosti dezinfitsiruyuschikh sredstv (s ispolzovaniem ustanovki Glas-Kol modeli 099S F4224). [Guidelines on procedure for handling aerosols of microorganisms in order to assure bactericidal action of disinfectants (using Glas-Kol Model of 099C F4224). Approved by Scientific Council FBUN GNC PMB as of 21.05.2014).

5. MR 3.5.1.0103.15 Metodicheskie rekomendatsii po primeneniyu metoda aehrozo lnoy dezinfektsii v meditsinskikh organizatsiyakh. [MR 3.5.1.0103.15 Guidelines on using aerosol disinfection in medical units]. Approved by Rospotrebnadzor as of 28.09.2015.

6. Parker C. Reist. Aerosoli, vvedeniyey v teoriyu. (Russ. Ed.: Parker C. Reist. Aerosol Science and Technology). B.F. Sadovskiy, eds. Moscow, Mir Publ., 1987, pp. 21.

7. Pokrovskiy V.I., Аkimkin V.G., Briko N.I., Brusina E.B., Zueva L.P., Kovalishena O.V., Stasenko V.L., Tutelyan А.V., Feldblyum I.V., Shkarin V.V. Natsionalnaya kontseptsiya profilaktiki infektsiy, svyazannykh s okazaniem meditsinskoy pomoschi, i informatsionny material po ee polozheniyam. [National concept of prevention of infections related to medical care and information materials on its provisions]. N. Novgorod, Remedium Privolzhye Publ., 2012.

8. Rezolyutsiya Kongressa s mezhdunarodnym uchastiem Kontrol' i profilaktika infektsiy, svyazannykh s okazaniem meditsinskoy pomoschi (ISMP-2016). [Resolution of Congress with international participation on monitoring and prevention related to medical care provision (ISMP-2016)]. Moscow, November 10-11, 2016, Available at: http://niid.ru/press/release/145645/

9. Rukovodstvo Sistema infektsionnogo kontrolya v protivotuberkuleznykh uchrezhdeniyakh. [Guidelines on infection control system in TB units]. L.S. Fedorova, eds. Moscow, Tver, 2013, pp. 5.

10. SanPiN2.1.3.2630-10 «Sanitarno-epidemiologicheskie trebovaniya k organizatsiyam, osuschestvlyayuschim meditsinskuyu deyatel'nost'» s izmeneniyami na 10 iyunya 2016 g. [SanPiN2.1.3.2630-10 on sanitary and epidemiological requirements to medical organizations, with changes as of June 10, 2016].

11. Tekhova I.G. Аerozolnaya dezinfektsiya v sisteme profilaktiki infektsiy, svyazannykh s okazaniem meditsinskoy pomoschi. [Aerosol disinfection in the system of prevention of infections related to medical care provision]. St. Petersburg, 2017, Available at: http://spbmiac.ru/wp-content/uploads/2017/06/Aerozolnaya-dezinfektsiya-vsisteme-profilaktiki-infektsij_Tehova-I.G.pdf

12. WHO Executive Committee, One-hundred-and-thirty-fourth session EB134/12, Report of the Secretariat: «Global strategy and goals for the prevention, treatment and control of tuberculosis beyond 2015». Available at: http://apps. who.int/gb/ebwha/pdf_files/EB134/B134_12-ru.pdf).

13. WHO Implementation of WHO's «Stop TB» Strategy Handbook for National TB Control.Available at: http://apps.who.int/iris/bitstr eam/10665/85531/1/9789241546676_rus.pdf).