Surgical Sites Infection After Gastrointestinal Surgeries in a Public Teaching Hospital in Sudan

Background: Surgical site infections (SSIs) are common healthcare-associated infections and associated with prolonged hospital stays, additional nancial burden, and signicantly hamper the potential benets of surgical interventions. Causes of SSIs are multi-factorials and patients undergoing gastrointestinal tract (GIT) procedures carry a high risk of bacterial contamination. This study aimed to determine the prevalence, associated factors, and causing microorganisms of SSIs among patients undergoing GIT surgeries. Methods: A hospital based, cross-sectional study conducted at Soba University Hospital (SUH) in Khartoum, Sudan. We included all patients from all age groups attending the GIT surgical unit at SUH between September-December 2017. We collected data about the socio-demographic characteristics, risk factors of SSI, and isolated microorganisms from patients with SSIs. Data analysis was done using the SPSS software version 20 (SPSS Inc., Chicago, IL, USA). A Chi-square test was conducted to determine the relationship between the independent categorical variables and the occurrence of SSI. The signicance level for all analyses was set at p < .05. Results: A total of 80 participants were included in the study. The mean age was 51 +/- 16 years and most of the patients (67.5%) did not have any chronic illness prior to the surgical operation. Most of them (46.3%) of them underwent large bowel surgery. Twenty-two patients (27.5%) developed SSI post operatively and supercial SSI was the most common type of SSIs (81.8%). Occurrence of SSI was found to be associated with long operation time (p > .001), malignant nature of the disease (p > .001), intra-operative blood loss (p > .001), and intra-operative hypotension (p =.013). The most prevalent microorganism isolated from SSI patients was E coli (47.8%), followed by Enterococcus fecalis (13.0%) and combined Pseudomonas aeruginosa + E coli infection (13.0%). Conclusion: The results showed a high prevalence of SSIs among patients attending the GIT unit in SUH and the most prevalent microorganism


Introduction
Surgical site infection (SSI) is the most frequent type of healthcare-associated infections, accounting for 14% -25% of the total hospital-acquired infections (1)(2). SSI is associated with a prolonged hospital stay, long-term disability, and additional nancial burden, and signi cantly hampers the potential bene ts of surgical interventions (3). Notably, SSI is theoretically preventable but requires a particular investigation of early diagnosis and intervention (3).
The incidence of SSIs can vary across surgical procedures, specialties, and conditions, with a range of 0.1% to 50.4% as reported in a 2017systematic review (4). A prevalence survey in the UK National Health Service (NHS) indicated that approximately 8% of all patients (5743 out of 75,694 patients over a four-month period) admitted to hospital suffered healthcare-associated infections, with 15% of these infections being SSIs, and similar estimates have been found in France (3). In Africa, the impact of SSIs ranged from 6.8% to 26% with predominance in the general surgeries (4).
Although there are global variations around the de nition of an SSI, the European Com mission classi ed SSIs into super cial incisional surgical site infection, deep incisional sur gical site infection, or surgical site infection -organ/space, and the di agnostic criteria include the presence of one of the signs of infec tion (tenderness, swelling, reddening, and elevated skin tempera ture), purulent discharge from the incision site, and positive result of microbiological examination of material collected or after the surgical opening of the incision site (5) (6).
While the causes of SSIs are multi-factorial, recognized risk factors include the length of hospital stay, obesity, patient co-morbidities, duration and complexity of the surgery, and higher wound contamination classi cation (7). The Centers for Disease Control and Prevention (CDC), classi ed wounds by their level of contamination as Clean (Class 1): which are non infective operative wounds in which no in ammation is encountered, with no involvement of respiratory, gastrointestinal, genitourinary tract, and oropharyngeal cavity; Clean-contaminated (Class 2): operative wounds in which either the respiratory, gastrointestinal or the genitourinary tract is entered under controlled conditions and with the only minor contamination, as resulted from operations involving the biliary tract, appendix, and oropharynx, provided no evidence of infection or a major break in sterile technique is encountered; Contaminated (Class 3): fresh, accidental wounds, resulting from operations with major breaks in sterile technique or gross spillage from the gastrointestinal tract, and incisions in which acute, non purulent (free from pus) in ammation is encountered; and Dirty (Class 4): old traumatic wounds with retained devitalized tissue and those that involve existing clinical infection or perforated viscera (8).
The risk of developing an SSI is related to the level of contamination of the wound as demonstrated in recent surveillance of surgical infections in NHS hospitals in England, which showed that the SSI risk following gastrointestinal tract (GIT) procedures (especially large bowel surgery) reached 9.0% in 2018/19 (9). SSIs are a major health hazard that can be prevented by identifying the predisposing factors. This study aimed to determine the prevalence, associated factors, and most prevalent microorganisms of SSIs among patients undergoing GIT surgeries.

Study design and settings:
A hospital based, descriptive cross-sectional study conducted at Soba University Hospital (SUH) in Khartoum, Sudan during the period from September-December 2017. SUH is a liated with the University of Khartoum and provides a host of therapeutic and diagnostic services at the highest level in Sudan through specialized units served by well trained healthcare staff. The current capacity of the hospital is approximately 500 beds and there are two general surgery units at the department of surgery in STH. One of them is particularly specialized in the GIT and hepatobiliary conditions. Patients are booked for surgery from the referred clinics and then organized in the elective operations lists.

Data collection and analysis:
We included all patients from all age groups attending the GIT surgical unit at SUH between September-December 2017. Patients who died after admission to the hospital and before undergoing surgical procedures were excluded from the study. Data were collected from the medical records of patients including the operational sheets and anesthetic sheets. We collected data about the socio-demographic characteristics, risk factors of SSI, and isolated microorganisms from patients with SSIs.
After completion of data collection, data analysis was done using the SPSS software version 20 (SPSS Inc., Chicago, IL, USA). A Chi-square test was conducted to determine the relationship between the independent categorical variables and the occurrence of SSI. The signi cance level for all analyses was set at p < .05.

General characteristics of the participants:
A total of 80 participants were included in the study. Patients' ages ranged from 20 to 98 years and the mean age was 52.3 +/-16.3 years. 53.8% of them were males and 46.3% were females. Most of the patients (67.5%) did not have any chronic illness prior to the surgical operation and 46.3% of them underwent large bowel surgery. Thirty nine patients (48.8%) underwent clean-contaminated surgeries as well as another 39 patients underwent contaminated surgeries (Table. 1 Occurrence of SSI was found to be associated with long operation time of more than three hours (p > .001), malignant surgical diseases (p > .001), intra-operative blood loss (p > .001), and intra-operative hypotension (p = .013). The most prevalent microorganism isolated from SSI patients was E. coli (47.8%), followed by Enterococcus fecalis (13.0%) and combined Pseudomonas aeruginosa + E. coli infection (13.0%) ( Table. 2)

Discussion
The results of this study showed that 27.1% of the patients had SSI. Several risk factors were found to be signi cantly associated with the development of SSI including: malignant nature of the disease, intra-operative blood loss, intra-operative hypotension, and long operation time.
Majority of the patients had super cial wound infections, which were discovered mostly during post-operative hospital stay with drainage from the wound site 5-6 days post operatively. Those patients with SSIs were handled according to the standard guidelines and wound dressing twice per day was offered for patients with SSI.
The higher risk of acquiring SSI among patients with malignant diseases compared to patients with benign diseases is reasonable since malignancy is associated with weak immune system and vulnerability to various infections, and it is consistent with studies reported that SSI was observed in 30-60% of patients after colorec tal cancer surgeries (5,(14)(15). The lack of association between SSI and timing of SAP is similar to another retrograde cohort study (28). According to the standard guidelines, SAP should be given 60 minutes before the incision in most of types of antibiotics and doubling of the dose should be considered when the duration of operation exceeds 4 hours (29).
There was a signi cant association between SSI and intra-operative blood loss of more than 500 ml like another study showed the 26.1% of those who had massive intra-operative blood loss developed wound infection (16). This is relevant since blood loss is directly related to decreased tissue oxygenation and aiding in the development of SSI. Also, intra-operative hypotension is found to be strongly related to SSI as previously reported (17)(18), and this is related to the poor wound perfusion resulting from intra-operative hypotension.
The association between SSI and long duration of operation of more than 180 min match a systematic review that showed the same results in most of its studies (19). It has been demonstrated that there was an 80% increase in likelihood of SSI with surgeries longer (versus shorter) than three hours (20). Prolonged operative time allows time for over-handling the wound edges and also contact with contaminated uids coming out of the surgical eld.
The most prevalent micro-organisms isolated were E coli and Enterococcus fecalis, whilst other studies showed that Staphylococcus aureus was the most common isolated bacteria from different wound types (30)(31). Pseudomonas aeruginosa are commonly isolated in infected wounds following surgeries and burns, whereas Enterobacteriaceae are commonly isolated from wounds in immune compromised patients and abdominal surgeries (30)(31). These virulent isolated microorganisms need to be put in high consideration and further elaboration to be done regarding this issue.

Conclusion
The results showed a high prevalence of SSI among patients attending the GIT unit in SUH and it was associated with the malignant diseases, intraoperative blood loss, intra-operative hypotension, presence of surgical drains, and long operative duration. The most prevalent microorganism isolated was E coli. Measures should be taken to decrease intra-operative blood loss, reduce the waste of time due to any cause intra-operatively so as to reduce the overall duration of operation.

List Of Abbreviations
SSI: surgical sites infection; SAP: surgical antibiotics prophylaxis; SUH: Soba University Hospital Declaration Ethics approval and consent to participate: Ethical clearance was obtained from the Ministry of Health, Khartoum, Sudan. Permission for conducting this study was obtained from the head department of surgery at the hospital. Con dentiality of the study participants was maintained.

Consent for publication Not applicable
Availability of data and materials: The datasets used during the current study are available from the corresponding author on reasonable request.
Competing interests The authors declare that they have no competing interests Funding: No fund