Study of Bacterial Contamination in Operating Theatres at Al-Hussein Teaching Hospital in Al-Samawah, Iraq

Document Type : Original Articles


1 University of Al-Muthanna, College of Nursing, Samawah, Iraq

2 Al-Safwa University College, Nursing Department, Karbala, Iraq

3 Al-Muthanna Governorate Health Department, Samawah, Iraq


The continuing bacterial contamination in hospitals operating units and theaters has an important role in the spread of hospital infections. The current study evaluated the level of bacterial contamination in the operating theatres at Al-Hussein Teaching Hospital in Al-Samawah, Iraq. For the purpose of sample collection from surgical equipment surfaces, the swab plate method conducted by nurses and laboratory workers was used to collect the samples in the operating theater. The samples were then transferred to the laboratory unit for diagnosis by standard methods. The present study found different rates among operating theatres. According to bacterial contamination rate, especially for the operating theatre in emergency wings with 334 contaminated isolates, the highest rates of contaminated bacterial isolates were Staphylococcus epidermidis (n=171; 26.1%), Bacillus species (spp.) (n=118; 18%), S. aureus (n=111; 16.9%), Klebsiella spp. (n=92; 14%), Enterobacter spp. (n=82; 12.5%), P.aurogenosa (n=24; 3.7%), and Escherichia coli (n=23; 3.7%). Despite the use of all methods of sterilization among the hospital wards, especially the surgical halls in the hospital wards, bacterial contamination is still widespread among these units. It was noted that the bacteria isolated in this study posed a risk as pathogenic bacteria.


Main Subjects

1. Introduction

Bacterial contamination from operating theatres has a clear and tangible effect on the spread of infection in hospitals, especially hospital-acquired infections ( 1 , 2 ). Bacterial contamination in operating theatres would be considered one of the most life-threatening sources of nosocomial infection for patients. Nosocomial infection occurred especially in heart and transplant surgeries, cystoscopy, transurethral resection of prostate, as well as bladder tumors. Several responsible reservoirs for hospital contamination have been reported, particularly for the operating theatre bacterial contaminations that include unfiltered air, ventilation systems, antiseptic solutions, and cold surgical device. Operating theaters are an integral part of healthcare around the world; however, surgeries are also associated with a high risk of complications and death from contamination ( 3 , 4 ). In previously published studies, it was shown that most hospital-acquired infections were pathogenic bacteria resistant to many drugs, such as Pseudomonas species (spp.) and Staphylococcus aureus ( 5 , 6 ). Many studies indicate that the bacteria involved in contaminating operating theaters are Enterobacter spp. (about 8.5%) ( 7 , 8 ), Escherichia coli (about 4.0%), and S. epidermidis (about 8.3%) ( 9 ). Therefore, the current study aimed to investigate the percentages and types of bacterial contaminations involved in the operating theatres of Al-Hussein Teaching Hospital, Iraq; moreover, it was attempted to provide a contamination model in the operating theatres of the government hospitals across Iraq.

2. Materials and Methods

2.1. Study Design

A laboratory investigation-based cross-sectional study was carried out at the operating theatres of Al-Hussein Hospital in Al-Samawah, Iraq, during 2020. Al-Hussein Hospital is situated in the center of Al-Samawah and provides in/outpatient care. There are five operating theatres in the hospital for surgical services (general, private wings, as well as gastroenterology, ophthalmology, and emergency wards).

2.2. Sample Collection

The sample swabs were obtained from the surgical instrument surfaces, such as gauze, probes, scissors, forcipes, blades, needles, and scrub practitioners. Moreover, other samples were collected from floors, walls, sinks, door handles, water taps, trolleys, and arms using swabs with and without charcoal media for the transport of facultative anaerobic and aerobic microorganisms. Individually packaged swabs (BD Culture Swab MaxV+) were used to collect samples by the laboratory staff and transported to the microbiology laboratory within 3 h of collection ( 10 ). The swabs were inoculated to sterile peptone water and then subjected to subculture to MacConkey agar, blood agar, nutrient agar, and thioglycolate broth. After an incubation period of 18-24 h at 37°C in aerobic and anaerobic conditions, the plates were investigated for visible growth. Subculture was conducted for Cloudy thioglycolate broth to MacConkey and blood agar and then incubated as described. The isolated bacteria were diagnosed by reference methodology ( 11 - 13 ) and an identification system using mass spectrometry for bacterial diagnosis technology (Vitek MS, BioMérieux). Surface samples were collected in the morning time after disinfection and before the beginning of operations.

2.3. Statically Analysis

Statistical analysis was carried out in IBM SPSS software (version 20.0), and categorical variables were expressed as frequency and percentage (%).

3. Results and Discussion

A total of 656 isolates of contaminated bacteria (both Gram-positive and negative) were recovered from different surfaces of surgical stuff and equipment in five surgical operating theatres of Al-Hussein Teaching Hospital during one year (2020). Table 1 tabulates that Pseudomonas aeruginosa isolates were roughly equal in terms of isolation percentages in most of the five operating theatres, while it was noticed that Gram-positive isolates (S. aureus) had a high different percentages among operating theatres, especially operating theatre 1 (general operating theatre with 75 contaminated isolates).

Operating theatres Oper 1 Oper 2 Oper 3 Oper 4 Oper 5
No. examinations 420 420 420 420 420
No. % No. % No. % No. % No. % Total
Negative isolates 290 69 346 82.4 365 86.9 357 85 86 20.5 1444
P. aeruginosa 6 1.4 4 0.95 3 0.7 5 1.2 6 1.4 24 (3.7%)
S. aureus 75 18 13 3.1 5 1.2 12 2.9 6 1.4 111(16.9%)
E. coli 2 0.5 8 1.9 3 0.7 4 0.95 6 1.4 23 (3.5%)
Enterobacter spp. 4 0.95 5 1.2 2 0.5 2 0.5 69 16.4 82 (12.5%)
Bacillus spp. 8 1.9 10 2.4 12 2.85 9 2.1 79 18.8 118 (18%)
Klebsiella spp. 7 1.7 3 0.7 3 0.7 1 0.2 78 18.6 92(14%)
S. epidermidis 28 6.7 21 5.0 19 4.5 26 6.2 86 20.5 180(27.4%)
S. pneumonia 0 0 2 0.5 0 0 0 0 1 0.2 3 (0.2%)
Enterococcus faecalis 0 0 1 0.2 0 0 0 0 2 0.5 3 (0.2%)
S. thoraltensis 0 0 1 0.2 0 0 2 0.5 0 0 3 (0.2%)
Acinetobacter spp. 0 0 2 0.5 3 0.7 0 0 0 0 5(0.76%)
Citrobacter spp. 0 0 1 0.2 0 0 2 0.5 0 0 3 (0.2%)
Streptococcus spp. 0 0 3 0.7 5 1.2 0 0 1 0.2 9 (1.4%)
Total positive isolates 130 31.1 74 17.6 55 13.1 63 15.1 334 79.4 656/2100
Table 1.Distribution of positive bacteria isolates in each operating theatre of Al-Hussein Teaching Hospital, Al-Samawah, Iraq

The surgical operating theatre of emergency wards (Oper 5) achieved a high contamination rate with Enterobacter spp., Bacillus spp., Klebsiella spp., and S. epidermidis, compared to the rest of operating theatres for contaminated bacterial isolates. According to this table, isolation percentages are very low with regard to S. pneumoniae, S. epidermidis, Enterococcus faecalis, S. thoraltensis, Acinetobacter spp., Citrobacter spp., and general Streptococcus spp. isolates (Figure 1).

Figure 1. Percentages of positive bacteria isolates in operating theatres

In Iraq, various studies have found different percentages of contaminated bacteria (Gram-positive and negative). According to a study conducted in Al-Yarmouk Teaching Hospital in Baghdad, Iraq, the contaminated bacterial isolates within three years included P. aurogenosa (n=195; 35.8%), (n=137; 43.4%), and (n=48; 53.3%), followed by E. coli (n=141; 25.9%), (n=115; 30.0%), and (n=28; 39.8%), respectively ( 14 ).

Another study was conducted in two operating theaters at the main units of Abubakar Tafawa Balewa University Teaching Hospital, Bauchi Nigeria, in 2015. The results explained that the isolation rates of Staphylococci (n=33; 38.8%) and S. aureus (n=24; 28.2%) predominated in both units, followed by Bacillus spp. (n=8; 9.4%), Klebsiella pneumonia (n=4; 4.7%), Acinetobacter spp. (n=1; 1.2%), Enterobacter spp. (n=1; 1.2%), and Enterococcus spp. (n=4; 4.7%) ( 15 ).

The present study showed that emergency operating theatres had a high number of both Gram-positive and negative contaminated isolates (n=334), followed by general operating theatre with frequent contaminated isolates (n=134), and the private operating theatre (n=74) with frequent contaminated isolates. The rest of the operating theatres (gastroenterology and ophthalmology) had 63 and 55 bacterial isolates, respectively (Figure 2).

Figure 2. Total positive bacteria isolates according to operating theatres

The bacterial contamination in the operating theatres (surgical item/equipment) is still a high impact factor and a major contributor to the increase of infections at the site of the operating unit and during the surgery process. The concomitant negative effects include prolonged hospitalization, as well as an increase in medical cost, and even difficulty of managing the patients' care that lead to the elevation of morbidity and mortality rate ( 16 - 18 ).

Bacterial contamination of equipment and inanimate items (projector, operating couch, anesthesia machine, floor, wall, suction machine, gauze, surgical instrument, and iodine), showed high contamination rates of Bacillus spp. (n=21; 28%) and S. epidermidis (n=19, 25.3%) isolates from operating floors, while in the operating couch, it was estimated at 14.7% (n=48). All operating theaters were contaminated by S. epidermidis (n=19; 39.5%) and S. aureus (n=10; 20.3%). Moreover, the contamination percentages of projectors, anesthesia machines, walls, and suction machines were 12.6% (n=41), 18.7% (n=61), 10.1% (n=33), and 14.1% (n=46), respectively (Figure 3). The most contaminated isolates were S. aureus and S. epidermidis, while few pathogens were recovered from gauze, surgical instruments, and iodine.

Figure 3. Distribution of bacterial isolates according to operating theater equipment and furniture

Similar studies have reported different contamination rates of Pseudomonas spp. (23.9%) and Bacillus spp. (17.5%) from floors ( 7 ), and 1.8% for iodine contamination ( 19 ).

The antibiotic resistance style exhibited a relatively high resistance for some antibiotics, especially P. aeruginosa that resist Nafcillin and Gentamicin (100%). Similarly, E. coli was resistant to Claforan and Ceftazidime (100%). The other isolates exhibited different resistance to other antibiotics (Table 2). Such operating theatres, in which bacteria were isolated, must apply disinfecting methods. The nurses and laboratory workers should accomplish the requirement for a high level of hygiene that leads to reducing more bacterial contaminations. Similar results were obtained from a previously conducted study ( 20 ). Despite the use of all methods of sterilization among the hospital wards, especially the surgical halls in the hospital wards, bacterial contamination is still widespread among these units. It was noted that the bacteria isolated in this study posed a risk as pathogenic bacteria that can be reduced by developing the disinfection and cleaning methods periodically.

Antibiotic/bacteria P. aeruginosa No. (27) S. aureus No.(58) E. coli No. (18) Enterobacter spp. No. (14) Bacillus spp. No. (66) Klebsiella spp. No. (10) S. epidermidis No. (114)
R% R% R% R% R% R% R%
Nafcillin 100 100 16.6 35.7 100 40 50
Nalidixic acid 37 60.3 50 42.9 33.3 50 69.3
Colistin 74 34.5 88.9 57 37.9 80 50
Claforan 85.1 60.3 100 100 27.3 70 55.3
Amoxicillin 29.2 100 50 50 22.7 40 18.4
Ceftazidime 92.5 86.2 100 50 60.6 100 18.4
Coftriaxone 22.2 32.8 33.3 35.7 18.2 20 8.7
Chloramphenicol 55.6 55.2 77.8 50 37.9 50 29
Amikacin 74 60.3 88.9 78.5 33.3 40 22.2
Gentamicin 100 89.6 50 64.2 45.5 70 22.8
Trimethoprim 59.2 68.9 55.5 50 22.7 20 20.1
Tobramycin 48.1 68.9 50 35.7 15.1 50 17.5
R=Resistance, No.=number
Table 2.Antibiotic resistance pattern of bacterial isolates of the present study

Authors' Contribution

Study concept and design: H. H. M.

Acquisition of data: S. R. O.

Analysis and interpretation of data: D. M. H.

Drafting of the manuscript: S. S. H.

Critical revision of the manuscript for important intellectual content: H. H. M.

Statistical analysis: S. R. O.

Administrative, technical, and material support: H. H. M.


The present study was approved by the Ethics Committee of the University of Al-Muthanna, College of Nursing, Samawah, Iraq.

Conflict of Interest

The authors declare that they have no conflict of interest.


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