Assessment of probiotic effects on colorectal surgery complications: A double blinded, randomized clinical trial

Background: Probiotics are living bacteria, which can be used as a food supplement to produce inhibitory agents and compete with pathogens in the guts. Nowadays, because of the easy accessibility and misuse of antibiotics, probiotic usage is increasing. The goal of our study is to assess the effects of probiotics on colorectal surgery complications. Methods: The enrolled cases were selected from colorectal surgery candidate patients, who referred to Sina and Imam Reza Hospitals of Tabriz University from April of 2016 to April of 2017. They were divided into two groups of study and control. For the study group, 7 days before surgery, one capsule of probiotics (Familact) was administrated every night, while the control groupwas given capsules of placebo. Results: Although the infective complications, mortality ratio and duration of hospitalization in the study group were lower than the control group, these differences were not statistically significant. Discussion: Our study confirmed that preoperative probiotic consumption in colorectal surgery had not affected complications or mortality of surgery and this finding is in disagreement with some previous studies. Perhaps, other strains of bacteria or different dosage, duration and rout of administration can have positive effects on these complications. Conclusion: This study showed that there was no correlation between probiotic consumption preoperatively and decreased complications or mortality after colorectal surgery.


INTRODUCTION
Probiotics are living bacteria that can be used as food supplementary to produce inhibitory agents to compete with pathogens in the guts. They can stimulate and regulate the immune system and improve the balance of intestinal microbes [1][2][3] . Recent studies showed that probiotics can reduce the absorption of cholesterol and decrease the risk of colorectal cancer 4 . Probiotics can also help improving diseases such as diarrhea, constipation, allergies, inflammatory bowel disease, irritative bowel syndrome, peptic ulcer and lactose intolerance, and can prevent autoimmune diseases and hypertension [5][6][7] . The combination of probiotics and prebiotics (food ingredients that induce the growth or activity of beneficial microorganisms) is known as "synbiotics" 8 . Synbiotics help to improve the resistance of the gastrointestinal tracts to infected diseases by improving the immune system and antimicrobial activities 9 . Probiotics colonize in the gastrointestinal tract and oropharynx. They prevent the changes of normal flora into pathogens and have preventive effects on hospital pneumonia 8,10,11 . Nowadays because of the easy accessibility and misuse of antibiotics, their usage is increasing, which leads to growing resistance of the microorganisms 12 . Recent studies showed that preoperative administration of probiotics in patients with colorectal cancer can reduce infective complications after surgery [13][14][15] . The goal of our study is to assess the effects of probiotics on the colorectal surgery complications.

METHODS
This is a randomized clinical trial and a prospective study. The enrolled cases were selected from colorectal surgery candidate patients, who referred to Sina and Imam Reza Hospitals of Tabriz University of Medical Sciences, Tabriz, Iran, from April 2016 to April 2017. All 18-to 80-year-old patients with good nutritional status were divided into two parallel groups of study and control. Exclusion criteria were set for patients with no agreement for participation in study, having intestinal or colon obstruction, consuming anticoagulant agents or any other drugs that prolong duration of hospitalization, having progressive cardiopulmonary diseases or Class IV of ASA (American Society of Anesthesiologists) or chronic renal failure, having a history of chemotherapy, or patients with organ transplantation, cirrhosis, antibiotics usage one week be-

Randomization and blinding
We used statistical software in www.randomizer.org for double blinded randomization. Two equal groups received either probiotics or placebos. Each group consisted of 50 patients and the sample size was determined according to previous studies 15 . Two boxes labelled A (probiotics) and B (placebo) were prepared

Procedure
For the study group, 7 days before surgery, one capsule of probiotics (Familact) was administered every night. Each capsule contains Lactobacillus casei & Lactobacillus acidophilus (1.75 x 10 9 CFU), Lactobacillus plantarum (0.5 x10 9 CFU), Bifidobacterium breve (1.75 x 10 9 CFU), Bifidobacterium longum (1.5 x 10 9 CFU), and Streptococcus thermophilus, and the control group was given placebo capsules. For bowel preparation, one day before surgery, four packets of oral polyethilenglycol with two litres of water was administrated. All patients took oral erythromycin 800 mg and metronidazole 500 mg at 13, After the operation, each patient was given one oral capsule daily when awake. Each patient was given 30 capsules in total. The control group received similar treatments except that placebo was used instead of probiotics.

Measures
Variables of the study including gender, age, past medical history, measurement of haemoglobin, incidence of anastomosis leakage, cutaneous or subcutaneous infection on incision line, facia dehiscence, other infections (pneumonia, urinary tract infection, central venous catheter infection and sepsis), duration of hospitalization and mortality ratio were defined.

Statistical Analysis
All data were analysed by SPSS version of 15. We used chi-square test for qualitative variables analysis and ttest for quantitative variables. P-Values of ≤ 0.05 were considered reliable.

Ethics
The study design was approved by Human Research Review and Ethics Committee of Tabriz University of Medical Sciences. All patients were informed about the study, and they had to sign the consent letter for voluntary cooperation. Also, they could leave the study at any time. All personal information were confidential. The only intervention in the treatment was the prescription of Familact capsules. A company of Zist Takhmir produced these capsules as OTC (Over-The-Counter) drugs that had no complications in studies until now. Costs of study were funded by the Vice Chancellor for Research (VCR) of Tabriz University of Medical Sciences.

RESULTS
There were no significant differences in gender, age, past medical history and haemoglobin levels between two groups (P-value> 0.05) ( Table 1). There were no reports of anastomosis leakage or facia dehiscence from two groups. Three patients (6%) in the study group and 5 patients (10%) from control group developed cutaneous and subcutaneous tissues infection on incision line after surgery. However, this difference was not statistically significant (P-value = 0.46). There was one case of central venous catheter infection in the study group. There was one case of pneumonia that led to respiratory failure and death, and one case of central venous infection in control group, however, there were no significant differences (P-value=0.60 and 0.31) in other infective complications and mortality ratio between two groups. Mean of hospitalization duration of the study group was 5.96 ± 2.53 days (Max = 12days, Min = 3 days) and of the control group was 6.10 ± 2.44 days (Max = 15 days, Min = 3 days), which showed no significant differences (P-value = 0.30) Table 2.

DISCUSSION
In this study, the effects of probiotic consumption on complications of elective colorectal surgery and its mortality ratio was assessed. The results showed that probiotics had no positive effect on patients after surgery. McNaught et al. (2002) showed that preoperatively (1 week) oral probiotic (lactobacillus+ plantarum 299v) administration in 129 patients with elective abdominal surgery had no positive effects on the growth of beneficial bacteria in guts, nor did it help to improve the resistance of intestinal cells or decrease the postoperative complications and mortality 16 . These results were in agreement with our study. In the study of Anderson and McNaught et al. (2004), candidate patients for elective abdominal surgery took synbiotics (probiotics such as Lactobacillus acidophilus La5 with prebiotics like oligofructose) for 2 weeks. There was no significant difference between control and study groups, which confirmed our study results 17 . Most studies in these field showed different results. In the study of Sagawara et al. (2006), patients, who were candidates for hepatectomy with bile duct carcinoma and liver hilum involvement, were divided into two groups of receiving synbiotics or placebo (for two weeks before surgery). The results showed that the administration of synbiotics preoperatively increased lymphocytes and natural killer activities, and decreased the production of IL-6. Also, in the group receiving synbiotics only after surgery, white blood cells count was significantly lower compared to control group, thus, synbiotic administration before surgery could improve the immune system 18 . Rayes et al. (2007) showed that synbiotics had positive effects on patients. They administrated synbiotics through intestine and found that infection ratio and antibiotic requirements in group treated with lactobacillus probiotics were significantly lower compared to controls 19 . Liu et al. (2011) in a randomized clinical trial had prescribed oral probiotics to colorectal cancer patients 6 days before and 10 days after colorectal surgery, and   Consoli et al. (2016) studied about probiotic (Saccharomyces boulardii) consumption in patients with colon surgery and the levels of inflammatory cytokines. They found that in the study group, the levels of mucosal IL-1 beta, IL-10 and IL-23 were lower and probiotic administration before surgery had no effect on infective complications, duration of hospitalization and mortality 25 .
A numerous causes could affect the results of our study, including the strains of probiotics that were used. Perhaps, other strains of probiotics could be considered in future research. Moreover, dosage, duration and different routes of probiotic administration, such as direct administration into the jejunum, could be considered for further research. On the other hand, prophylactic antibiotics can also reduce the effect of probiotics and need to be taken into account in the future.

CONCLUSIONS
This study showed that there is no correlation between probiotic consumption preoperatively and the decrease in complications and mortality after surgery. Study with larger groups, longer administration of probiotics or synbiotics, longer follow-up duration and other administration routes are recommended.