Microbial Contamination in Surgery at Al-Zahraa General Teaching Hospital
In the precise world of surgery, an unseen battle unfolds between medical science and microscopic invaders.
Walk into any modern operating theater, and you'll be struck by its gleaming surfaces and atmosphere of controlled sterility. Yet, despite this apparent cleanliness, an invisible world of microorganisms coexists with the life-saving procedures performed there. These microscopic inhabitants—bacteria, fungi, and viruses—pose a significant threat to surgical outcomes, turning the operating room into a front line in the fight against hospital-acquired infections.
At Al-Zahraa General Teaching Hospital, as in surgical centers worldwide, understanding and controlling this microbial landscape is a matter of life and death. Surgical site infections (SSIs) remain one of the most common complications following surgical procedures, affecting millions of patients globally each year and presenting substantial challenges to healthcare systems 6 9 . This article pulls back the curtain on the hidden microbial world in operating theaters and explores the scientific efforts to create safer surgical environments.
Surgical site infections account for approximately 14-17% of all hospital-acquired infections and 38% of nosocomial infections in surgical patients 9 .
In the highly controlled environment of an operating theater, numerous microorganisms manage to survive despite rigorous cleaning protocols. These pathogens can originate from various sources, including airborne particles, medical staff, surgical equipment, and even the patients themselves 4 6 .
The most common culprits found in operating theatre studies include:
The distribution of these microorganisms isn't random; specific pathogens tend to colonize different areas of the operating theater. A 2021 study found that operating tables and walls were frequently contaminated with pathogenic organisms, while air sampling revealed varying bacterial loads depending on the type of surgical procedures performed .
Based on data from the Baghdad Hospital Study 1
| Microorganism | Primary Source | Infection Risk |
|---|---|---|
| Staphylococcus aureus | Patient and staff skin, nasal passages | Wound infections, bacteremia |
| Staphylococcus epidermidis | Human skin flora | Infections involving medical devices |
| Pseudomonas aeruginosa | Moist environments, water sources | Respiratory infections, surgical site infections |
| Escherichia coli | Human gastrointestinal tract | Urinary tract infections, intra-abdominal infections |
| Bacillus species | Environment, soil, dust | Contamination indicator, occasional infections |
Table 1: Common Pathogens Found in Operating Theatres and Their Sources
To understand how researchers investigate microbial contamination in operating theaters, let's examine a revealing study conducted at Al Imam Ali Hospital in Baghdad—a setting similar to Al-Zahraa General Teaching Hospital 1 . This research provides a template for how we might investigate and understand the microbial challenges at Al-Zahraa.
From February 2001 to December 2002, researchers undertook a comprehensive surveillance of microbial contamination across 12 operating theaters specializing in various surgical disciplines, including general surgery, orthopedics, delivery, ophthalmology, and ENT procedures 1 .
Over two years, they collected 1,216 swabs from surfaces, equipment, and antiseptic solutions in the operating theaters. Samples were taken 2-3 times monthly, both before and after surgical procedures 1 .
The swabs were directly cultured on two types of growth media—MacConkey agar and blood agar—using the streaking method to isolate individual bacterial colonies. The inoculated plates were incubated aerobically at 37°C for 24 hours 1 .
Researchers then performed a series of biochemical tests to identify the bacterial species, including oxidase, catalase, coagulase, indole, methyl red, Voges-Proskauer, and citrate utilization tests 1 .
This methodical approach allowed the scientists to not only detect microbial contamination but also track how contamination patterns changed over time and differed between various types of operating theaters.
The study revealed several important patterns in operating theater contamination:
The overall rate of positive bacterial cultures was 3.7% in 2001 and 4.0% in 2002, indicating a persistent, though relatively low, level of contamination 1 . While these percentages might seem small, considering the critical nature of surgical environments, even minor contamination can have serious consequences for vulnerable patients.
Perhaps more interestingly, the predominant contaminating organisms shifted significantly between the two years. In 2001, Staphylococcus epidermidis was the most common isolate (39.1%), followed by Pseudomonas aeruginosa (30.4%). However, in 2002, coliform bacteria became the dominant contaminants (62.5%), with P. aeruginosa remaining second (25.0%) 1 .
Contamination rates over the two-year study period 1
| Year | Total Samples | Positive Cultures | Positive Culture Rate | Most Common Pathogen | Second Most Common |
|---|---|---|---|---|---|
| 2001 | 622 | 23 | 3.7% | Staphylococcus epidermidis (39.1%) | Pseudomonas aeruginosa (30.4%) |
| 2002 | 594 | 24 | 4.0% | Coliform bacteria (62.5%) | Pseudomonas aeruginosa (25.0%) |
Table 2: Microbial Contamination Rates in the Baghdad Hospital Study
| Operating Theatre Type | Primary Isolates in 2001 | Primary Isolates in 2002 |
|---|---|---|
| General Surgery | Staphylococcus epidermidis | Coliform bacteria |
| Fracture | Staphylococcus epidermidis (highest concentration) | Coliform bacteria |
| Delivery | Pseudomonas aeruginosa (highest concentration) | Coliform bacteria, Pseudomonas aeruginosa |
| Ophthalmic | Staphylococcus epidermidis | Coliform bacteria |
| ENT | Staphylococcus epidermidis | Coliform bacteria |
Table 3: Distribution of Bacterial Isolates by Operating Theatre Type
Understanding the invisible microbial world of operating theaters requires specialized tools and techniques. Researchers use a combination of traditional and advanced methods to detect and identify microorganisms.
The passive air sampling method involves leaving Petri dishes with nutrient media exposed to the air for a specified period, allowing airborne microorganisms to settle onto the surface 2 . After incubation, the developed colonies are counted and identified.
Surface sampling uses swabs or contact plates pressed against various surfaces in the operating theater—floors, walls, equipment, and surgical tables 3 . These samples are then transferred to growth media in the laboratory for analysis.
Active air sampling employs mechanical devices that draw a known volume of air onto collection media, providing a more quantitative assessment of airborne microbial contamination 4 .
Real-time PCR (polymerase chain reaction) enables rapid detection of specific microorganisms without waiting for them to grow in culture 5 . This method is particularly valuable for identifying slow-growing or fastidious pathogens.
Whole-genome sequencing offers the highest level of identification, allowing researchers to track the spread of specific bacterial strains and determine whether infections originate from a common source 6 .
| Research Tool | Primary Function | Application in Operating Theatre Studies |
|---|---|---|
| MacConkey Agar | Selective growth medium | Isolation and differentiation of gram-negative bacteria, particularly coliforms |
| Blood Agar | Nutrient-rich medium | Detection of hemolytic activity and cultivation of fastidious pathogens |
| Contact Plates | Surface sampling | Direct imprinting of surfaces to detect microbial contamination |
| Biochemical Test Reagents | Bacterial identification | Differentiation of bacterial species based on metabolic characteristics |
| PCR Master Mixes | DNA amplification | Rapid detection of specific pathogens without culture |
| Air Samplers | Active air monitoring | Quantitative assessment of airborne microbial load |
Table 4: Essential Research Reagents and Their Functions in Microbial Surveillance
The battle against microbial contamination in operating theaters requires a multidisciplinary approach and the commitment of all healthcare professionals 9 . Based on research findings, several strategies have proven effective:
Implementing and maintaining proper ventilation systems with HEPA filtration and achieving more than 20 air changes per hour have shown better results in improving operating room air quality 6 .
Recent research emphasizes the importance of coordinated efforts among surgeons, anesthetists, technicians, and nurses to implement effective infection prevention strategies 8 .
Continuous surveillance of microbial contamination coupled with ongoing training programs ensures staff understand and implement the latest evidence-based practices 9 .
The invisible world of microbes in operating theaters presents an ongoing challenge to modern healthcare. Studies like the one conducted in Baghdad provide valuable insights into the patterns of contamination and their implications for patient safety. As research continues to evolve, the focus remains on creating increasingly safer surgical environments through evidence-based practices, technological innovation, and interdisciplinary collaboration.
At Al-Zahraa General Teaching Hospital and similar institutions worldwide, the battle against microbial contamination represents a fundamental commitment to patient safety—a reminder that in the high-stakes world of surgery, what we cannot see can be just as important as what we can.
"The art of medicine consists of amusing the patient while nature cures the disease."