This article was presented in 10th Infection Control Congress.
Introduction
Healthcare-associated infections (HAIs) are a common issue worldwide and pose a persistent threat to the effective and proper functioning of healthcare facilities. These infections can unintentionally lead to a reduction in the quality of healthcare services . In medical literature, these infections are sometimes referred to as Hospital-Acquired Infections (HAIs), but the more common term is “nosocomial infections.” The term “nosocomial” originates from the Greek words Nosos (disease) and Komeion (care). The World Health Organization (WHO) provides a broader definition, referring to these as Health care-associated infections .
With the increasing global population, the rise in the number of healthcare facilities, the growing diversity of healthcare services, and the increased life expectancy, HAIs have become a critical health priority. According to WHO reports, one out of every 11 patients receiving healthcare is affected by an infection. In developed countries, 7% of patients, and in developing countries, 10% of patients, acquire at least one type of HAI. Of those infected, nearly 10% die from the infection . Overall, 8.7% of hospitalized patients contract HAIs , with rates in Iran reported to range from 9.1% to 25% .
HAIs not only prolong hospital stays but also increase microbial resistance, mortality, and complications, imposing a significant economic burden on both patients and healthcare providers. A notable percentage of surgical site infections may be caused by antibiotic-resistant microbes . Epidemiological studies have identified factors increasing the risk of HAIs, including patient age (more common in the elderly and newborns), underlying diseases, the length of hospital stay, a weakened immune system, and invasive diagnostic or therapeutic procedures such as urinary catheters or ventilator-associated pneumonia.
While effective infection control programs can reduce the spread of HAIs, mortality, antibiotic resistance, and associated costs , it’s crucial to note that the main pathogens causing HAIs are microorganisms from patients’ own bodies, which are transmitted between patients or by healthcare staff . These pathogens are primarily spread through the air, by other patients, nurses, medical staff, visitors, or through invasive devices like surgical instruments and catheters. It is estimated that 25% to 50% of HAIs result from the influence of natural microflora and invasive devices.
Based on these definitions, HAIs are infections that occur 48 to 72 hours after a patient is admitted to the hospital , provided the patient did not have the infection or its incubation period upon admission . There are 13 main types of infections, with four major HAIs accounting for 81% of all cases: urinary tract infections, lower respiratory tract infections (pneumonia), surgical site infections, and bloodstream infections. Among these, urinary tract infections are the most common, and pneumonia is the deadliest .
Considering the importance of HAIs and the need to find solutions for their control, addressing this issue can reduce the mortality and complications of these infections, improve public health, and enhance satisfaction with healthcare systems. Given the clinical significance of this issue and the lack of precise statistics on HAIs, particularly in orthopedic hospitals, this study was conducted. The results of this study, in comparison with international data, could help identify shortcomings in the healthcare system and provide a logical approach to mitigating this problem.
The history of infection control in hospitals is ancient, dating back to the establishment of hospitals for patient care and treatment in the fourth century AD. Since the expansion of hospitals, HAIs have always been a major health concern. They prolong hospital stays, increase mortality, and significantly raise healthcare costs. The increasing number of hospitals, the emergence of re-emerging and new diseases, the growing resistance to antibiotics, and the demand for diverse medical services have made healthcare-associated infections inevitable .
According to WHO, 1.7 million HAIs occur annually, leading to 99,000 deaths and imposing a cost of $26 to $32 billion on society. A WHO study conducted on 55 hospitals in 12 countries revealed that 8.7% of hospitalized patients contract HAIs. Over the past two decades, the incidence of these infections has increased by 36% .
In Iran, various scattered studies have been conducted in university hospitals on HAIs. For example, a descriptive-analytical study in the second half of 2002 over six months, using the standard NNIS method, estimated the overall HAI rate in children under 12 years old at 8.5%, with the highest rates in the PICU .
In a study by Amini and colleagues in the ICU of Shahid Mostafa Khomeini Hospital, the overall HAI rate was 10.85%, with the most common infections being pneumonia (77.3%), urinary tract infections (18.7%), surgical site infections (2.7%), and bloodstream infections (1.3%) .
In a study in Kerman, 14.8% of patients had positive cultures for HAIs, with 44% of these cases in children. The most common pathogens were Staphylococcus, Escherichia coli, and Pseudomonas .
A systematic review and meta-analysis conducted in 2020 reported HAI rates ranging from 0.32% to 9.1% .
A study by Darvishpour and colleagues in 2013 found that HAI rates in Iran ranged from 1.9% to 25%. In this study, the most common infection site was the lungs, and the most common microbial cause was Acinetobacter .
In this study, the HAI rate from the beginning of 2021 to the end of December 2022 at this center was 0.51%.
According to a report by the Centers for Disease Control and Prevention (CDC), hospital-acquired infections (HAIs) result in the deaths of 2 million people annually in U.S. hospitals. Another study estimated the death toll from HAIs in the U.S. at 80,000 per year, with 247 people dying daily due to these infections. Additionally, for every 136 hospitalized patients, one becomes seriously ill due to an HAI. In developing countries, between 2 to 4 million HAIs occur annually, making them the 11th leading cause of death and the 5th leading cause of death in hospitals. These figures are from institutions with active surveillance and control systems, suggesting that infection rates in hospitals in our country may be even higher.
In the United Kingdom, 5,000 deaths annually are attributed to hospital-acquired infections. According to various studies, developed countries have an HAI-related mortality rate of 2-11%.
In this center, the reported mortality rate among 286 patients with hospital-acquired infections during the specified period was 3.49%.
One of the factors associated with an increased risk of hospital-acquired infections (HAIs) is the patient’s age. A study by Ghanbari et al. in 2014 at different departments of Shariati Hospital in Isfahan reported the highest infection rate (6.46%) in the age group of 60-80 years. Elderly individuals, due to their weakened immune systems, are more vulnerable to infections, and the likelihood of contracting hospital-acquired infections from opportunistic microorganisms increases in this population. Likewise, young children are also prone to HAIs due to their immature and underdeveloped immune systems.
The results of this study indicated that out of 102,692 hospitalizations in various departments of this center, from April 2021 to the end of December 2022, there were 286 cases of infection. The highest percentage of HAIs occurred in the young adult age group (25-44 years), accounting for 36.01% of the cases.
In the study conducted by Majzubi and colleagues in 2018, no statistically significant difference was observed between the incidence of hospital-acquired and community-acquired infections based on gender. In a similar study by Zamanzad, the target population was exclusively women. However, in the studies by Sadeghzadeh, Sohrabi, and Barak, the proportion of women with hospital-acquired infections was higher than that of men.
Regarding the distribution of infections by gender, out of the 286 cases of hospital-acquired infections, 72 cases were women (17.25%), and 214 cases were men (74.82%).
Urinary, respiratory, surgical site, and bloodstream infections are the major types of hospital-acquired infections. Urinary tract infections (UTIs) are the most common, with 80% linked to catheterization in patients. Respiratory infections occur in various patient groups, particularly those using mechanical ventilation in intensive care units (ICUs), where the daily infection rate is reported at 3%. Bloodstream infections account for a small portion of hospital-acquired infections—around 5%—but have a high mortality rate, with some microorganisms causing over 50% of deaths. Surgical site infections are also frequent, with an incidence ranging from 5% to 15%, depending on the type of surgery and the patient’s underlying condition. These infections can limit the potential benefits of surgical interventions and impact hospital costs and post-surgical stays by extending the duration of hospitalization by 3 to 20 extra days.
As mentioned earlier, hospital-acquired infections vary based on the affected site. The most common include urinary tract infections, respiratory infections, bacteremia, and skin infections such as surgical wounds and burn wounds.
In the 2019 study by Kouhestani and colleagues, the most frequent hospital-acquired infections were reported as urinary tract infections (39.76%), ventilator-associated infections (20.92%), bloodstream infections (20.71%), and skin and soft tissue infections (0.7%).
In Rezaei’s 2017 study, the most commonly affected organ systems in hospital-acquired infections were the urinary system, followed by the respiratory, circulatory, and integumentary systems, as well as other organs.
Another study found urinary tract infections to be the most common hospital-acquired infection (42%), followed by surgical site infections (24%), pneumonia (15% to 21%), and bloodstream infections (bacteremia) (2% to 11%).
In this study, 11 cases (84.3%) involved ventilator-associated pneumonia, 4 cases (39.1%) involved urinary tract infections, 9 cases (14.3%) involved bloodstream infections, and 144 cases (50.34%) involved surgical site infections.
As hospital expansion continues, hospital-acquired infections remain a major healthcare issue. These infections increase with prolonged hospital stays, leading to higher mortality rates and significantly raising hospital costs. The incidence of hospital-acquired infections varies across hospital departments. While ICUs improve recovery rates and reduce mortality, prolonged hospital stays and the use of various life-support devices contribute to an increased rate of hospital-acquired infections in these units, further complicating metabolic and immune responses and leading to organ failure.
Beyond the physical harm caused by medical or nursing care, hospital-acquired infections are a major cause of severe complications, higher mortality, extended hospital stays, prolonged disabilities, increased costs, and the rise of antibiotic resistance. According to the U.S. Department of Health, these infections cost the healthcare system $5 to $10 billion annually and result in 99,000 deaths each year.
In this study, the average hospital stay for patients with hospital-acquired infections was 24.3 days. The longest stays were observed in patients with bloodstream infections, particularly those in the ICU, who were typically treated for multiple conditions. Hospital-acquired infections further prolonged their hospital stays.
In the 2018 study by Mazdoubi and colleagues, 50% of hospital-acquired infections occurred within the first 11 days of hospitalization, and 75% occurred within 20 days of admission.
In the present study, the average time from admission to the onset of infection was 4.9 days.
Key microorganisms responsible for hospital-acquired infections include Gram-positive cocci such as Staphylococcus, Streptococcus, and Enterococcus, as well as Gram-negative bacilli like Acinetobacter, Pseudomonas, Escherichia coli, Klebsiella, Proteus, Serratia, and Enterobacter, which have become resistant to many common antibiotics.
In the 2019 study by Kohestani and colleagues, Escherichia coli was identified as the most common cause of hospital-acquired infections, followed by Klebsiella and Acinetobacter. Similarly, in studies by Rahmanian, Sohrabi, Laripour, Ghanbari, and Mancini, Escherichia coli was the leading cause of infections. Other studies have found Coagulase-negative Staphylococcus, Klebsiella, Pseudomonas aeruginosa, and Staphylococcus aureus as the most common culprits of hospital infections.
At this center, during the study period, the most common pathogens responsible for hospital-acquired infections were Staphylococcus aureus (21.79%), Escherichia coli (13.84%), Acinetobacter (4.15%), Enterobacter (7.26%), and Citrobacter (3.8%).
Since the 1980s, Gram-positive microorganisms, particularly Staphylococcus aureus, have been identified as the primary cause of hospital-acquired infections. Staphylococcus aureus is responsible for a wide range of diseases, including mild skin infections and life-threatening systemic illnesses like septicemia, endocarditis, pneumonia, and deep skin abscesses, both hospital-acquired and community-acquired. It has developed resistance to a broad spectrum of antibiotics, including beta-lactams, macrolides, and more. The primary infection sites caused by this bacterium are wounds, respiratory secretions, and the skin.
In Amiri’s 2018 study, antimicrobial susceptibility testing using the disk diffusion method on 67 Staphylococcus aureus isolates revealed the following resistance rates to six different antibiotics, according to CLSI guidelines: 100% resistance to penicillin, 44.7% to oxacillin, 38.8% to vancomycin, 32.3% to tetracycline, 25.7% to gentamicin, and 10.5% to chloramphenicol.
In a 2021 study by Masgarian and colleagues, microorganisms were examined based on their susceptibility or resistance to specific antibiotics using the disk diffusion method. It was found that out of 31 positive Pseudomonas cultures, 16 were resistant to carbapenems (53%); out of 94 positive Acinetobacter cultures, 70 were resistant to carbapenems (74%); out of 34 positive E. coli cultures, 7 were resistant to carbapenems (20%); and out of 27 positive Klebsiella cultures, 12 were resistant to carbapenems (45%). In a study by Mahler and colleagues in Germany, 5,171 multi-drug resistant Gram-negative bacilli were identified, with 16% showing resistance to carbapenems.
In the 2019 study by Yaghoubi and colleagues, Acinetobacter, Pseudomonas, Enterobacter, Klebsiella, Escherichia coli, and Staphylococcus aureus showed the highest levels of antibiotic resistance. Acinetobacter was the most prevalent among the six microorganisms studied. Based on the results, Acinetobacter showed the highest resistance to cefazolin, ampicillin, and cephalexin, and the lowest resistance to tobramycin, while it was most sensitive to ofloxacin and amikacin.
Antibiotic resistance in hospital-acquired infections is increasing, particularly due to the overuse of antibiotics in recent years, especially in intensive care units, leading to the emergence of resistant isolates. Multi-drug resistant hospital-acquired infections are associated with increased complications, mortality, and healthcare costs, resulting in approximately 35,000 deaths annually.
In Swayeh and colleagues’ study, the highest resistance among Gram-negative bacteria was observed against beta-lactams, and resistance to cotrimoxazole was also high. In Mazdoubi and colleagues’ 2018 study, resistance of Gram-negative bacteria (excluding Enterobacter) to beta-lactams was above 50%. Among cephalosporins, the highest resistance was to ceftriaxone, and the lowest was to ceftizoxime, with imipenem resistance exceeding 40%. Overall, common microorganisms in hospital-acquired infections showed the highest resistance to nalidixic acid, carbenicillin, doxycycline, and cotrimoxazole, underscoring the importance of avoiding the indiscriminate prescription of antibiotics by physicians.
In this study, microorganisms were also examined for susceptibility or resistance to specific antibiotics using the disk diffusion method. Staphylococcus aureus showed 100% resistance to oxacillin or cefoxitin and clindamycin, and 93.75% resistance to vancomycin. Escherichia coli showed 100% resistance to third- or fourth-generation cephalosporins and beta-lactamase inhibitors, and 93.3% resistance to fluoroquinolones.
Based on the results of this study, it can be stated that hospital-acquired infections are an increasing therapeutic challenge. Healthcare personnel and those involved in patient care must focus on controlling and preventing these infections by adhering to necessary infection control standards to prevent their growing prevalence. Considering the economic impact and increased morbidity associated with these infections, it is crucial to control their occurrence as much as possible. Among the preventive measures for hospital-acquired infections, hand hygiene by staff, adherence to infection control standards, and increasing staff awareness are of significant importance. Hospital-acquired infections are an undeniable component of healthcare facilities, and following care principles is a primary goal for preventing and controlling them, serving as a major reason for designing infection control programs.
