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Year : 2017  |  Volume : 7  |  Issue : 3  |  Page : 165-168  

Microbiological surveillance of operation theatres: Five year retrospective analysis from a Tertiary Care Hospital in North India

1 Department of Microbiology, Acharya Shri Chander College of Medical Sciences and Hospital, Jammu, Jammu and Kashmir, India
2 Department of Pathology, Acharya Shri Chander College of Medical Sciences and Hospital, Jammu, Jammu and Kashmir, India

Date of Submission06-Jul-2016
Date of Acceptance10-Dec-2016
Date of Web Publication14-Aug-2017

Correspondence Address:
Dipender Kaur Najotra
207-D, Uttam Nagar, Kunjwani Bye Pass, Jammu 180 010, Jammu and Kashmir
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijabmr.IJABMR_281_16

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Introduction: Microbiological contamination of air and environment in the operation theaters (OTs) are major risk factor for surgical site and other hospital-associated infections. Objectives: The aim was to identify bacterial colonization of surfaces and equipment and to determine the microbial contamination of air in the OTs of a tertiary care hospital. Materials and Methods: Five years (January 2010–December 2014) retrospective analysis of the data obtained from routine microbiological surveillance of the five OTs of the hospital was done. Surface samples were taken with wet swabs from different sites and equipment. Bacterial species were isolated and identified by conventional methods. Air quality surveillance of OTs was done by settle plate method. Results: A total of 4387 samples were collected from surfaces and articles of various OTs. Out of these only 195 (4.4%), samples showed bacterial growth and yielded 210 isolates. The predominant species isolated was Bacillus with 184 (87.6%) isolates followed by coagulase-negative Staphylococcus 17 (8.1%), Staphylococcus aureus 6 (2.9%), and Enteroccoccus spp. 3 (1.4%). Analysis of the OT air samples showed least colony forming unit (cfu) rate of air (27 cfu/m3) in ophthalmology OT and highest rate of 133 cfu/m3 in general surgery OT. Conclusion: The study shows that OTs of our hospital showed a very low bacterial contamination rate on surface swabbing and a cfu count per m3 of air well within permissible limits.

Keywords: Microbiological, operation theater, surgical site infection, surveillance

How to cite this article:
Najotra DK, Malhotra AS, Slathia P, Raina S, Dhar A. Microbiological surveillance of operation theatres: Five year retrospective analysis from a Tertiary Care Hospital in North India. Int J App Basic Med Res 2017;7:165-8

How to cite this URL:
Najotra DK, Malhotra AS, Slathia P, Raina S, Dhar A. Microbiological surveillance of operation theatres: Five year retrospective analysis from a Tertiary Care Hospital in North India. Int J App Basic Med Res [serial online] 2017 [cited 2021 Oct 26];7:165-8. Available from: https://www.ijabmr.org/text.asp?2017/7/3/165/212961

   Introduction Top

Hospital-associated infections are an important source of morbidity and mortality with postoperative, surgical site infections (SSI) being the second most common cause after urinary tract infections.[1],[2],[3],[4] Sources of infection can either be endogenous or exogenous from the theater environment like air, surfaces, articles in operation theater (OT). The Factors on which the rate of postoperative infections depend are effective sterilization and disinfection procedures, surgical technique, theater design, bacterial contamination of theater air, OT discipline, and appropriate use of prophylactic antibiotics.[4],[5],[6],[7]

Microbiological surveillance is an important part of infection control program, providing data regarding types, and counts of microbial flora.[8],[9] The present study was conducted to identify bacterial colonization of surfaces and equipment in the OTs and to determine the microbial contamination of air in the OTs of a tertiary care hospital.

   Materials and Methods Top

This retrospective study, analyzing the microbiological surveillance data from OTs over a period of 5 years from January 2010 to December 2014 was conducted at a tertiary care hospital. The study was approved by Institutional Ethical Committee. Two sampling procedures used in the study were surface swabbing and settle plate method. Sterile gloves, masks, and sterile gown were worn for collection to prevent the contamination of media and OT surface being swabbed.

The surface samples were taken after proper sterilization and disinfection of the OTs, before the entry of surgery and support team. Sterile swabs soaked in nutrient broth were used for sample collection from different sites and equipment (instrument trolley, table top, lights, monitor, wall, floor, etc.) of five OTs of the hospital. They were labeled properly and transported immediately to the microbiology laboratory for processing. Inoculation was done on Blood Agar and MacConkey Agar and incubated at 37°C for 24 h under aerobic condition. Bacterial species were isolated and identified by conventional methods.[10]

Air sampling was done by settle plate method. Open Blood Agar plates labeled with sample number, theater site, time and date of sample collection were kept at about 1 m above the ground, 1 m from the wall and exposed for 1 h when the OTs were operational following the schedule 1/1/1.[11] These plates after incubation at 37°C for 24 h in microbiology laboratory were observed for growth and number of colonies per plate were counted. Further, this colony forming unit (cfu) count/plate was expressed as cfu/m 3 by Omeliansky formula;[12] N = 5a × 104 (bt)−1 where N = colony forming unit per cubic meter of air (cfu/m 3), a = number of colonies per petridish, b = surface area of petridish in cm 2, and t = time exposure (minutes).

   Results Top

A total of 4387 surface swab samples were taken from the five OTs of the hospital during the study. Out of these, 900 samples per OT were collected from General Surgery, Urology, Orthopedics and ENT OTs whereas 787 samples were from Ophthalmology OT. The culture positivity rate of these surface swabs was 4.4% (195/4387) and 4192 (95.6%) samples were culture negative. These 195 culture positive swabs yielded 210 isolates. Therefore, single isolate was obtained from 180 swabs and 15 swabs gave two isolates. Bacillus spp. with 184 (87.6%) isolates was the most common bacterial isolate followed by coagulase-negative Staphylococcus (CoNS) with 17 (8.1%) isolates [Figure 1]. The highest number of culture positive swabs (n = 92) and isolates (n = 98) were obtained from General Surgery OT where 6 samples yielded two isolates. Least number of culture positive samples (n = 7) were obtained from Ophthalmology OT where each sample gave one isolate [Table 1].
Figure 1:

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Table 1: Operation theater wise distribution of n=210 bacterial isolates from surface swabs

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The bacterial cfu/m 3 counts of air were in range of 27–133 with Ophthalmology OT having the least count and General Surgery OT the highest count [Figure 2].
Figure 2:

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   Discussion Top

Microbial contamination in OT leading to postoperative infections can have serious implications for patients and their families. Any case of suspected hospital-acquired infection (HAI) is investigated by including cultures from other body sites of the patient, other patients, staff, and environment.[13] Careful selection of specimens to be cultured is essential to obtain meaningful data. Infections prolong hospital stays, create long-term disability, increase resistance to antimicrobials, represent a massive additional financial burden for health systems and cause unnecessary deaths. Thus, the solution is a well-implemented infection control program which can improve staff education and accountability, also by conducting research to adapt and validate surveillance protocols based on the reality of developing countries to achieve acceptable performance. This can reduce the incidence of HAIs by around one-third.[14] Of all the procedures and protocols, the environmental disinfection and instrument sterilization definitely requires the most critical monitoring.

In the present study, 4387 surface swabs were collected from five OTs of the hospital with a bacterial contamination rate of 4.4% (n = 195) which is quite low compared to other studies where positivity rate ranged from 14.7% to 100%. The probable reason for this variability is first these studies were all for a short duration of few months whereas the observation period in the present study was extended for 5 years. Second, the swabs were collected before the commencement of surgeries after proper sterilization and disinfection whereas in some studies either the swabs were taken randomly or the time of collection has not been mentioned. In this study, Bacillus spp. which is considered to be an environmental contaminant was the predominant isolate followed byCoNSwhich is a commensal organism. This is in concordance with other studies from India and abroad.[3],[7],[9],[15] Six isolates of Staphylococcus aureus were obtained during 5 years of surveillance which although is very low at 2.9% is a potential pathogen and an important cause of skin and soft tissue infections. Similarly, CoNS and Enterococcus spp. are also an important cause of SSI's.[16],[17]

The microbiological quality of air is the reflection of the hygienic conditions of the OT. Settle plates are supposed to be more sensitive in detecting the increase of microbial air contamination related to conditions that could compromise the quality of the air in operating theaters.[18] The OTs are considered suitable for carrying out most forms of surgical procedures only when the bacterial load is <180/m 3 of air.[19] In the present study, the count ranged between 27 and 133 cfu/m 3 of air which is well within permissible limits and correlates well with studies from Gujarat and Udaipur.[3],[9] Whereas there are other studies which have reported a very high counts from air sampling.[20],[21] The highly variable results in different studies can be ascribed to various factors like method of surveillance (active air sampling or passive air sampling), time of sampling, i.e. at rest or operational, ventilation of OTs and last but not the least the disinfectants being used and the methods of sterilization employed. Highest cfu count per cubic meter of air in our study was obtained from General Surgery OT and least from Ophthalmology OT which is in line with the study by Anjali et al. and is most probably due to highest patient load in the General Surgery OT.[9]

Our study highlights the fact beyond any doubt that periodic and regular microbiological surveillance of OTs is essential to detect and control contamination. If appropriate measures are taken based on feedback will definitely decrease the SSI rate. Other side of the coin is that there are no standard guidelines in India pertaining to the method of sample collection or its frequency for microbiological surveillance of OTs. Therefore, more extensive studies are required in this field so that national guidelines can be formulated for monitoring and surveillance to enable the comparison of compliance between various health-care facilities.

   Conclusion Top

The study shows that the microbiological quality of air and surfaces in OTs of our hospital is satisfactory with very low bacterial contamination rate on surface swabbing and a cfu count per m 3 of air well within permissible limits. Settle plate method for air and swabbing technique for surfaces are very useful, convenient and cost effective methods for surveillance of OTs even in resource limited settings.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Zerr DM, Garrison MM, Allpress AL, Heath J, Christakis DA. Infection control policies and hospital-associated infections among surgical patients: Variability and associations in a multicenter pediatric setting. Pediatrics 2005;115:e387-92.  Back to cited text no. 1
Ram J, Kaushik S, Brar GS, Taneja N, Gupta A. Prevention of postoperative infections in ophthalmic surgery. Indian J Ophthalmol 2001;49:59-69.  Back to cited text no. 2
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Fleischer M, Bober-Gheek B, Bortkiewicz O, Rusiecka-Ziólkowskaa J. Microbiological control of airborne contamination in hospitals. Indoor Build Environ 2006;15:53-6.  Back to cited text no. 5
Kelkar U, Kelkar S, Bal AM, Kulkarni S, Kulkarni S. Microbiological evaluation of various parameters in ophthalmic operating rooms. The need to establish guidelines. Indian J Ophthalmol 2003;51:171-6.  Back to cited text no. 6
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Anjali K, Anamika V, Mrithunjay K, Dalal AS, Kumar A. Environmental microbiological surveillance of operation theatres in a tertiary care hospital. Int J Curr Res 2015;7:13977-80.  Back to cited text no. 9
Collee JG, Miles RS, Watt B. Tests for the identification of bacteria. In: Collee JG, Fraser AG, Marmion BP, Simmons A, editors. Mackie and McCartney Practical Medical Microbiology. 14th ed. Edinburg: Churchill Livingstone; 1996. p. 131-50.  Back to cited text no. 10
Pasquarella C, Pitzurra O, Savino A. The index of microbial air contamination. J Hosp Infect 2000;46:241-56.  Back to cited text no. 11
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World Health Organization, Regional Office for South-East Asia. New Delhi. Guidelines on Prevention and Control of Hospital Associated Infections; 2002. P. 42.  Back to cited text no. 13
Kallel H, Bahoul M, Ksibi H, Dammak H, Chelly H, Hamida CB, et al. Prevalence of hospital-acquired infection in a Tunisian hospital. J Hosp Infect 2005;59:343-7.  Back to cited text no. 14
Singh K, Dar FA, Kishor K. Bacterial contamination in operating theatres of district hospital Budgam in Kashmir division. Innov J Med Health Sci 2013;3:62-3.  Back to cited text no. 15
Owens CD, Stoessel K. Surgical site infections: Epidemiology, microbiology and prevention. J Hosp Infect 2008;70 Suppl 2:3-10.  Back to cited text no. 16
Najotra DK, Kakru DK. Bacteriology and antibiogram of skin and soft tissue infections from a tertiary care hospital. Indian J Med Spec 2012;3:26-30.  Back to cited text no. 17
Pasquarella C, Masia MD, Nnanga N, Sansebastiano GE, Savino A, Signorelli C, et al. Microbial air monitoring in operating theatre: Active and passive samplings. Ann Ig 2004;16:375-86.  Back to cited text no. 18
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Napoli C, Marcotrigiano V, Montagna MT. Air sampling procedures to evaluate microbial contamination: A comparison between active and passive methods in operating theatres. BMC Public Health 2012;12:594.  Back to cited text no. 21


  [Figure 1], [Figure 2]

  [Table 1]

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