Ocena czynników ryzyka i schemat epidemiologiczny zakażeń szpitalnych po operacjach ginekologicznych w Szpitalu im. Imama Chomejniego w Ahwazie w latach 2011–2016

Introduction

Nosocomial infection is not present at the beginning of a patient’s hospitalisation or during hospitalisation or post-discharge [1]. Millions of dollars are used worldwide to diagnose, treat, and compensate for complications of nosocomial infection, which is one of the main causes of mortality in patients across the world [1–3]. The prevalence of nosocomial infections in the world is between 5% and 25% [2], i.e. this level cannot be expected to be zero even in the best equipped centres, so each centre should have the latest information in this regard and try to reduce it. In Iran, the Centre for Disease Management in the Ministry of Health and Medical Education has reported numbers in the same range for nosocomial infection in different centres [4, 5]. Healthcare-associated infections (HAI) are one of the most common and severe complications of hospitalisation and are a serious threat to the health of the hospitalised patients [6]. These conditions increase the risk of diseases and death, and increase hospital costs due to the increasing number of hospital days, long-term diagnostic and therapeutic care, and long-term absence from work and family [3]. Nosocomial infections may affect any part of the body, but the most common types of nosocomial infections are: urinary tract infection, respiratory infections, surgical site infections, septicaemia, and other types of infections (AIDS and hepatitis) [1–3]. Among the HAI cases, surgical site infection (SSI) occurs after surgery. A surgical site infection is defined as the occurrence of any infection in the opened tissue or organ and the manipulated cavity during surgery [7]. The term SSI replaced the term surgical wound infection in 1992 [8]. Postoperative infections are among the most common complications after many surgical procedures, sometimes even leading to the failure of surgical goals and causing irreparable injury to the patient [9, 10]. Surgical site infection occurs in 5–10% of the patients [1–5]. Common causes include Gram-positive cocci and Gram-negative bacilli [1–3]. The most common of the Gram-positive cocci is Staphylococcus aureus, which is found abundantly in the patient’s skin and transferred to the patient, especially to the surgical site from the hands of the hospital staff. Gram-negative bacilli include Escherichia coli, Klebsiella, and pseudomonas. Several factors make the wound susceptible to the next infection, which are classified into three categories: A) patient factors, including: old age, immune deficiency, obesity, diabetes mellitus, malnutrition, peripheral vascular disease, anaemia, and recent surgery; B) local factors, including: pre-surgery skin contamination, equipment contamination, inadequate pre-operative antibiotic prophylaxis, prolonged operation time, topical necrosis, hypoxia, and low body temperature (hypothermia); and C) microbial agents, including long-term admission, toxin secretion, and antibiotic resistance [11]. Surgical wounds are divided into four categories: clean, contaminated clean, contaminated, and dirty. Several methods have been used to reduce the risk of post-operative infections, such as heat therapy, oxygen therapy, antibiotics, surgical site preparation, sterilization of surgical instruments, and, most importantly, preoperative skin preparation [11]. Considering the number of hospitalised patients in the Department of Obstetrics and Gynaecology, preventing the spread of hospital infection in these patients is of particular importance because, in addition to physical and psychological damage to the patient, surgical infection increases the cost of treatment, bed occupancy rate, duration of stay in the hospital, and the incidence of postoperative complications in women.

Aim of the research

Because few studies have been conducted and implemented in this field in Khuzestan Province, this study was designed and conducted to investigate the predisposing factors and determine the epidemiological pattern of postoperative infection in patients admitted to the Department of Obstetrics and Gynaecology of Imam Khomeini Hospital in Ahwaz.

Material and methods

After obtaining permission from the Ethics Committee of Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran, the records of all patients who had reported to Imam Khomeini Hospital Infection Control Unit from the beginning of April 2011 to the end of March 2016 were included in a descriptive study to evaluate the parameters affecting surgical sites in patients admitted to the Department of Obstetrics and Gynaecology of Imam Khomeini Hospital in. Ahvaz, were reported as surgical infection sites of gynaecological surgery. According to the instructions for the control of nosocomial infections of the Ministry of Health and Medical Education Department, postoperative infection is defined as an infection that occurs within one month of surgery and has infectious secretions (colour, odour, and abnormal volume) as an infectious surgical wound, and the scar specimen is also positive. All cases were carefully reviewed. Individual information such as patient’s age, history of specific diseases, history of surgery, etc. were extracted from the patient’s records, and other information, such as the type of surgery, emergency or elective surgery, and any signs of infection including fever, secretions from the surgical site, the type of antibiotic received before surgery, and the type of microorganism grown from the wound secretions, were extracted from the patient’s records and recorded in pre-determined checklists.

Statistical analysis

The mean and standard deviation were used on quantitative variables, and frequency and percentage were used in qualitative variables to describe the data. All analyses were performed using SPSS version 22.

Results

The average age of the patients was 30.59 ±9.52 years, range: 15–82 years. Of these, 25.8% of patients were within the age range of less than 25 years old, 50% in the age range of 25–35 years, and 24.2% were more than 35 years old. Most of the patients were between the ages of 25 and 35 years. In addition, 11.6% of patients had diabetes, 7.1% had hypertension, and 81.3% had no underlying disease. The prevalence of diabetes in patients was higher than elevated blood pressure. The type of surgery performed in 78.8% of patients was caesarean section, 11.1% hysterectomy, 2% laparotomy, 4% episiotomy, and 4% other surgical procedures. The most common operation was caesarean section. Moreover, 22.2% of the patients underwent the surgery in the elective state and 77.8% in the emergency condition. Therefore, the majority of patients underwent surgery in the emergency condition. The type of microorganism cultured in 2% of the patients were Staphylococcus coagulase negative + Escherichia coli, 1.5% Staphylococcus coagulase positive + Escherichia coli, 3.5% Escherichia coli + other microorganisms, 28.8% Escherichia coli, 7.1% Staphylococcal coagulase positive, 3% Staphylococcal coagulase negative + other microorganisms, 20.2% Staphylococcus coagulase negative, 9.6% Acinetobacter, 5.1% Klebsiella, 4% Pseudomonas aeruginosa, 7.6% Staphylococcus aureus, 4% Enterobacter, and 3.5% Streptococcus. Therefore, this study showed that Escherichia coli was the most frequently cultivated microorganism (Table 1).
The surgery was performed in 17.2% of patients in spring, 23.2% in summer, 27.3% in fall, and 32.3% in winter. Most patients had surgery in the winter. Invasive intervention for patients also showed that venous catheter was used for 97% of patients, intravenous catheter with urinary catheter was used for 3% of patients, and only intravenous catheter was used for the majority of patients. Regarding the importance of the type of microorganisms in nosocomial infections, this chapter examines the frequency of microorganisms in humans based on the study variables. It should be noted that the age range of the three categories of below 25 years old, 25 to 35 years old, and over 30 years old, diabetes and hypertension for type of disease, caesarean section and hysterectomy surgery for type of surgery, emergency and elective conditions for surgical condition, and finally the seasons of spring, summer, autumn, and winter during which the surgery took place were evaluated as variables in this chapter. Escherichia coli was more frequent than other microorganisms in all cases except in the case of hysterectomy and in autumn, for which positive staphylococcus coagulase was more frequent.

Discussion and conclusions

As mentioned in the results chapter, patients within the age range 25 to 35 years, those undergoing caesarean section, in winter, and having diabetes were more susceptible to postoperative infections than others, which should be considered by medical and nursing teams, medical science researchers, and health managers. Studies by other researchers were reviewed in order to compare the results of this study with other research done in this field. In the study by Yazdani et al. the use of immunosuppressive drugs (OR = 2.28), emergency operations (OR = 4.52), and diabetes mellitus (OR = 3.72) were identified as risk factors for nosocomial infection within 10 days of surgery [12]. The causes of diabetes and the emergency operation in their study were similar to the high prevalence of diabetes and emergency procedures in this study. Of course, in their study, the initial research population included all patients undergoing surgery, and the infection was studied. However, in the present study, the research population included patients who had a history of postoperative infections. However, this research population provided a better base for conducting more surgical operations with more variables that were not studied by Yazdani et al. In the study of Krieger et al. caesarean section followed by obesity (2OR), previous caesarean section (1.8OR), hypertension disorder (1.4OR), early rapture of membranes (1.3OR), pregnancy diabetes (1.2OR), and repetitive abortions (1.2OR) were the independent risk factors in patients who had undergone surgical site infection [13]. As in the present study, in the study by Krieger et al. diabetes and hypertension were among the variables associated with infection. The present study also looked at other surgical procedures in women, while Kriger et al. studied only caesarean section. Another study was conducted by Tuomi et al., which looked at women with hysterectomy for endometrial carcinoma. It was reported that a body mass index (BMI) greater than 30 kg/m², diabetes, and prolonged operation time with high risk of infection at the site of surgical incision, smoking, and lymphadenectomy are related to higher risk of infection in the organ [14]. The focus of their study was more on the location of the infection, but the common point in both studies was the high prevalence of diabetes. In addition, only hysterectomy patients were included in their study, while in the present study, other surgical operations related to women are also reviewed. A study by Mahdi et al. stated that cutaneous infection in women undergoing laparotomy was 3.5 times higher than the less invasive surgery [15]. Although the focus of Mahdi et al. was on female malignancies alone, they reached a different conclusion from the present study because caesarean section and hysterectomy were more common in the present study, while laparotomy was more commonly reported than any other infections in their study, which might be due to the difference in the study population, the different surgeons, and the difference in the time of surgery, which call for further studies. A population-based study by Schneid-Kofman et al. identified obesity (OR = 2.2), blood pressure (OR = 1.7), premature rupture of membranes (OR = 1.5), diabetes (OR = 1.4), emergency caesarean section (OR = 1.3), and giving birth to twins (OR = 1.6) as independent risk factors [16]. The present study mentioned diabetes, caesarean section, and emergency surgery among other variables as risk factors for infection. However, their study described these variables as predictors of post-operative infections. While in the present study, the frequencies of these variables are studied. In conclusion of both studies, caesarean section, diabetes, and emergency surgery were significantly associated with postoperative infections. Research results on the microorganisms derived from the cultivation of patients showed different results. Dhaliwal et al. reported that abdominal hysterectomy had a higher rate of infection compared to vaginal surgery, and the microorganisms most often responsible for infection were Enterococcus, Staphylococcus, and Klebsiella [17]. Unlike these results, caesarean section was more prevalent in the present study, and regarding the microorganisms cultured, it was found that Escherichia coli and the subsequent coagulase-negative Staphylococci were most prevalent, which could be due to differences in the research population and the different locations of studies. Chia et al. reported in their study that the highest rate of wound infection was related to hysterectomy and the lowest rate was related to laparoscopy, and most of the organisms were Staphylococcus aureus. Wound infection was higher in some crowded areas and among some surgeons [18]. Contrary to their study, Staphylococcus aureus alone was responsible for 7.6% of infections in the present study, while Escherichia coli was found in more than 28.8% of the cultures from patients. Unlike them, caesarean section was the most frequent in this study. Obviously, the studies reviewed in this section are just a few of the studies conducted on the predisposing factors of post-operative infections in women. Further studies and comparisons of findings with other studies further reinforce the findings of the present study. The results of this study and the review of other studies show that patients within the age range 25 to 35 years undergoing caesarean section in the emergency situation in winter and having diabetes are more susceptible to postoperative infections than others. Furthermore, Escherichia coli was the most common microorganism. In addition, what this study shared with other international studies was that diabetes and emergency surgery were more common than other variables in patients with postoperative infections. These cases require more attention from medical and nursing groups and healthcare managers.

Acknowledgments

The present study was retrieved from a dissertation which was approved by the Medical Ethics Committee of Ahvaz Jundishapur University of Medical Sciences, Ahvaz Iran, and all phases of the present study were supported by Ahvaz Jundishapur University of Medical Sciences, Ahvaz Iran.

Conflict of interest

The authors declare no conflict of interest.

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Address for correspondence:

Esmat Eghbal Bakhtiary
Student Research Committee
Ahvaz Jundishapur
University of Medical Sciences
Ahvaz, Iran
E-mail: jhd.researcher8@gmail.com