Postoperative changes of the microbiome: are surgical complications related to the gut flora? A systematic review

Emerging Insights into Postoperative Neurocognitive Disorders: The Role of Signaling Across the Gut-Brain Axis

The pathophysiological regulatory mechanisms in postoperative neurocognitive disorders (PNCDs) are intricately complex. Currently, the pathogenesis of PNCDs has not been fully elucidated. The mechanism involved may include a variety of factors, such as neuroinflammation, oxidative stress, and neuroendocrine dysregulation. Research into the gut microbiota-induced regulations on brain functions is increasingly becoming a focal point of exploration. Emerging evidence has shown that intestinal bacteria may play an essential role in maintaining the homeostasis of various physiological systems and regulating disease occurrence. Recent studies have confirmed the association of the gut-brain axis with central nervous system diseases. However, the regulatory effects of this axis in the pathogenesis of PNCDs remain unclear. Therefore, this paper intends to review the bidirectional signaling and mechanism of the gut-brain axis in PNCDs, summarize the latest research progress, and discuss the possible mechanism of intestinal bacteria affecting nervous system diseases. This review is aimed at providing a scientific reference for predicting the clinical risk of PNCD patients and identifying early diagnostic markers and prevention targets.

Influence of pancreaticoduodenectomy for periampullary carcinoma on intestinal microbiome and metabolites

Recent growing evidence suggests a role for intestinal microbiome and metabolites in patients' postoperative recovery. Therefore, there is a need to gain insight into the impact of pancreaticoduodenectomy for periampullary carcinoma on microbiome and metabolites and the potential impact of their changes on patients' condition. Based on 16S rDNA gene sequencing and untargeted metabolomic analysis, we found that the diversity and abundance of intestinal microbiome were significantly higher in patients preoperatively than postoperatively, and the level of intestinal probiotics was significantly lower after surgery compared with preoperatively. In addition, the choline metabolism level was increased and the amino acid metabolism level was decreased after surgery. A total of 53 differential microbiome and 52 differential metabolites were detected, and the differential metabolites were mapped to approximately 60 different KEGG metabolic pathways, of which 13 KEGG metabolic pathways had a differential metabolite number greater than 5. A total of 88 colony-metabolite pairs with significant positive correlation and 69 colony-metabolite pairs with significant negative correlation were identified. Our results reveal alterations in intestinal microbiome after pancreaticoduodenectomy, suggesting its association with postoperative complications. Moreover, the elevated choline metabolism level in postoperative patients may predict their poorer prognosis. At the same time, the decreased abundance of such probiotic bacteria as Prevotella spp. in the postoperative intestine of patients will affect the amino acid metabolism of the organism to some extent.

Successful Clinical Avoidance of Colorectal Anastomotic Leakage through Local Decontamination

AIM

An anastomotic leak is an unpredictable postoperative complication during recovery from colorectal surgery that may require a re-operation. Potentially pathogenic bacteria like Pseudomonas (and Enterococcus) contribute to the pathogenesis of an anastomotic leak through their capacity to degrade collagen and to activate tissue matrix metalloprotease-9 in host intestinal tissues. The microbiome, therefore, is the key to preventing an anastomotic leak after colorectal surgery. The aim of this trial was to investigate whether perioperative selective decontamination with a new mixture of locally acting antibiotics specially designed against Pseudomonas aeruginosa and Enterococcus faecalis can reduce or even stop early symptomatic leakage.

METHOD

All hospitalized patients in our University Clinic undergoing colorectal surgery with a left-sided anastomosis were included as two groups; patients in the intervention group received polymyxin B, gentamicin and vancomycin every six hours for five postoperative days and those in the control group did not receive such an intervention. An anastomotic leak was defined as a clinically obvious defect of the intestinal wall integrity at the colorectal anastomosis site (including suture) that leads to a communication between the intra- and extraluminal compartments, requiring a re-do surgery within seven postoperative days.

RESULTS

Between February 2017 and May 2023, a total of 301 patients (median age of 63 years) were analyzed. An anastomotic leak was observed in 11 patients in the control group (n = 152), but in no patients in the intervention group (n = 149); this difference was highly significant.

CONCLUSION

The antibiotic mixture (with polymyxin B, gentamicin and vancomycin) used for local decontamination in our study stopped the occurrence of anastomotic leaks completely. According to the definition of anastomotic leak, no further surgery was required after local perioperative decontamination.

Changes of Intestinal Flora and the Effect on Intestinal Function in Infants With Ventricular Septal Defect After Cardiopulmonary Bypass Surgery

This study aimed to investigate the changes in intestinal flora in infants with ventricular septal defect (VSD) after cardiopulmonary bypass (CPB) surgery and their potential relationship with postoperative gastrointestinal function recovery. Fecal samples of 20 infants with VSD were collected before and after CPB surgery at our hospital from September 2021 to March 2022. 16S rRNA was used to detect and analyze the fecal samples. The most abundant intestinal microbes in the preoperative intestinal flora were Enterococcus (37.14%), Bifidobacterium (20.71%), Shigella (8.15%), Streptococcus (5.19%), Lactobacillus (3.7%), Rothia (2.22%). However, the most abundant intestinal microbes in the postoperative intestinal flora were Enterococcus (49.63%), Bifidobacterium (12.59%), Shigella (10.37%), Streptococcus (8.14%), Rothia (4.43%). The diversity and species richness of intestinal flora after CPB surgery were significantly lower than those preoperatively. The intestinal Enterococcus content in patients with postoperative gastrointestinal dysfunction was significantly higher than that in patients without gastrointestinal dysfunction (P < 0.05). Intestinal Bifidobacterium content in patients with postoperative gastrointestinal dysfunction was significantly lower than that in patients without gastrointestinal dysfunction (P < 0.05). After surgery, the content of intestinal Enterococcus was negatively correlated with the full feeding time, and the content of intestinal Bifidobacterium was positively correlated with full feeding time. After CPB surgery, the diversity and richness of intestinal flora decreased, intestinal pathogenic bacteria increased, and beneficial intestinal bacteria decreased. An increase in Enterococcus and decrease in Bifidobacterium can increase the incidence of gastrointestinal dysfunction and prolong the recovery time of gastrointestinal function.

Effect of Surgery on Postoperative Levels of the Gut Homeostasis-Regulating Enzyme Intestinal Alkaline Phosphatase

BACKGROUND

Intestinal homeostasis is a crucial factor for complication-free short- and long-term postoperative recovery. The brush border enzyme intestinal alkaline phosphatase (IAP) is an important regulator of gut barrier function and intestinal homeostasis and prevents endotoxemia by detoxifying lipopolysaccharides (LPSs). As IAP is predominantly secreted by enterocytes in the duodenum, we hypothesized that pancreaticoduodenectomy (PD) leads to a significantly stronger decrease in IAP than other major abdominal surgery.

STUDY DESIGN

Pre- and postoperative blood, stool, and intestinal samples were collected from patients undergoing PD, as well as other major surgical procedures without duodenectomy. The samples were analyzed using enzyme histochemistry, the para -nitrophenyl phosphate method for IAP, and the limulus amebocyte lysate assay for LPS.

RESULTS

Overall, 88 patients were prospectively enrolled in the study. Fecal IAP activity negatively correlated with serum LPS (r = -0.3603, p = 0.0006). PD led to a significant decline in IAP compared to preoperative baseline levels (p < 0.0001). The decline in IAP correlated with the length of proximal small intestinal resection (r = 0.4271, p = 0.0034). Compared to controls, PD was associated with a much more pronounced reduction in IAP-also after adjusting for surgical trauma (operative time, blood loss; r = 0.4598, p = 0.0086). Simultaneously, PD triggered a clearly more prominent increase in serum LPS compared to controls (p = 0.0001). Increased postoperative LPS was associated with an elongated hospitalization (r = 0.7534, p = 0.0062) and more prominent in pancreatic cancer (p = 0.0009).

CONCLUSIONS

Based upon the functional roles for IAP, supplementation with exogenous IAP might be a new treatment option to improve short- and long-term outcome after PD.

Adverse Effect of the Duration of Antibiotic Use Prior to Immune Checkpoint Inhibitors on the Overall Survival of Patients with Recurrent Gynecologic Malignancies

PURPOSE

Antibiotic use preceding immune checkpoint inhibitor (ICI) treatment has been associated with a decreased efficacy of ICI in solid tumors. In this study, we evaluated the effect of antibiotic use before ICI therapy on oncological outcomes.

METHODS

We examined patients with recurrent gynecologic malignancies at two academic institutions. The clinical data, including antibiotic use within 60 days of ICI initiation, type of antibiotics, reasons for antibiotic use, body mass index, tumor site, chemotherapy-free interval, prior history of radiotherapy, disease control rate (DCR), and overall survival (OS), were assessed.

RESULTS

Of 215 patients, 22.9% (n = 47) received antibiotics before ICI treatment. The most common cancer was ovarian (52.1%, n = 112), followed by cervical (24.7%, n = 53) and endometrial (16.7%, n = 36). When we divided the cohort based on antibiotic use before ICIs, there were no significant differences in the DCR and baseline characteristics between the two groups. On multivariate analyses, the variables associated with poor OS were previous use of antibiotics for a cumulative duration of >14 days (HR 2.286, 95% CI 1.210-4.318; p = 0.011); Eastern Cooperative Oncology Group 2 or 3 (HR 4.677, 95% CI 2.497-8.762; p < 0.001); and chemotherapy-free interval of <6 months (HR 2.007, 95% CI 1.055-3.819; p = 0.034).

CONCLUSION

Prior use of antibiotics for a cumulative duration of >14 days was associated with reduced survival in recurrent gynecologic malignancies.

Collagenase-producing bacteria are common in anastomotic leakage after colorectal surgery: a systematic review

PURPOSE

Some gut bacteria can produce enzymes (collagenases) that can break down collagen in the intestinal wall. This could be a part of the pathophysiology of anastomotic leakage (AL). This systematic review aimed to investigate if such bacteria were present more frequently in AL patients versus non-AL patients following colorectal surgery.

METHODS

This systematic review was reported according to the PRISMA and AMSTAR guidelines. Before the literature search, a study protocol was registered at PROSPERO (CRD42022363454). We searched PubMed, EMBASE, Google Scholar, and Cochrane CENTRAL on April 9th, 2023, for randomized and observational human studies of AL following colorectal surgery with information on gastrointestinal bacteria. The primary outcome was bacteria with the potential to produce collagenase. The risk of bias was assessed with the Newcastle-Ottawa Scale, as all studies were observational.

RESULTS

We included 15 studies, with a total of 52,945 patients, of which 1,747 had AL, and bacteriological information from feces, mucosa, the resected specimen, or drain fluid was presented. In 10 of the 15 studies, one or more collagenase-producing bacteria were identified in the patients with AL. Neither the bacteria nor the collagenase production were quantified in any of the studies. The studies varied greatly in terms of sample material, analytical method, and time of collection. Studies using DNA sequencing methods did not report findings of collagenase-producing bacteria.

CONCLUSION

Collagenase-producing bacteria are more common in patients with AL following colorectal surgery than in patients without AL, but the significance is unclear. From the current studies, it is not possible to determine the pathogenicity of the individual gut bacteria.

Probiotics in Postoperative Pain Management

Postoperative pain is the unpleasant sensory and emotional experience after surgery, its origin being both the inflammatory reaction induced by the surgical trauma on the abdominal wall and the splanchnic pain induced by the activation of nociceptors of the viscera, which are highly sensitive to distension, ischemia, and inflammation. Nowadays, it is well recognized that there is a close relationship between the gut microbiome and pain perception, and that microbiome is highly affected by both anesthesia and surgical manipulation. Thus, efforts to restore the disturbed microbiome via supplementation with beneficial bacteria, namely probiotics, seem to be effective. In this article, the knowledge gained mainly from experimental research on this topic is analyzed, the concluding message being that each probiotic strain works in its own way towards pain relief.

Alterations of gut microbiome following gastrointestinal surgical procedures and their potential complications

Intestinal microorganisms play a crucial role in shaping the host immunity and maintaining homeostasis. Nevertheless, alterations in gut bacterial composition may occur and these alterations have been linked with the pathogenesis of several diseases. In surgical practice, studies revealed that the microbiome of patients undergoing surgery changes and several post-operative complications seem to be associated with the gut microbiota composition. In this review, we aim to provide an overview of gut microbiota (GM) in surgical disease. We refer to several studies which describe alterations of GM in patients undergoing different types of surgery, we focus on the impacts of peri-operative interventions on GM and the role of GM in development of post-operative complications, such as anastomotic leak. The review aims to enhance comprehension regarding the correlation between GM and surgical procedures based in the current knowledge. However, preoperative and postoperative synthesis of GM needs to be further examined in future studies, so that GM-targeted measures could be assessed and the different surgery complications could be reduced.

Gut microbiota in perioperative neurocognitive disorders: current evidence and future directions

Perioperative neurocognitive disorders (PND) is a common surgical anesthesia complication characterized by impairment of memory, attention, language understanding and social ability, which can lead to a decline in the quality of life of patients, prolong the hospitalization period and increase the mortality rate. PND has a high incidence rate, which has a great impact on postoperative recovery and quality of life of patients, and has caused a heavy economic burden to society and families. In recent years, PND has become an important public health problem. The high risk population of PND is more prone to gut microbiota imbalance, and gut microbiota may also affect the inflammatory response of the central nervous system through the microbiota-gut-brain axis. Meanwhile, Neuroinflammation and immune activation are important mechanisms of PND. Regulating gut microbiota through probiotics or fecal bacteria transplantation can significantly reduce neuroinflammation, reduce the abnormal activation of immune system and prevent the occurrence of PND. This review summarizes the research progress of gut microbiota and PND, providing basis for the prevention and treatment of PND.

Efficacy and safety of Chinese herbal medicine Wuwei Xiaodu Drink for wound infection: A protocol for systematic review and meta-analysis

BACKGROUND

Wound infection (WI) is a disease in which pathogenic bacteria invade and multiply in a wound after trauma or surgery, causing a systemic inflammatory response. WI triggers an immune response in the body, resulting in inflammation and tissue damage, as well as slowing down the healing process. The traditional Chinese medicine prescription of Wuwei Xiaodu Drink (WWXDD) has been widely used in clinical practice with good results. However, there is no high-level evidence to support this result. The purpose of this study was to evaluate the efficacy and safety of WWXDD in the treatment of WI.

METHODS

We will search articles in 7 electronic databases including Chinese National Knowledge Infrastructure (CNKI), Wanfang Data (WF), Chinese Scientific Journals Database (VIP), Chinese databases SinoMed (CBM), PubMed, Embase, and Cochrane Library databases. All the publications, with no time restrictions, will be searched without any restriction on language and status, the time from the establishment of the database to October 2022. Two reviewers will independently assess the quality of the selected studies, NoteExpress and Excel software will be used to extract data, and the content will be stored in an electronic chart. Different researchers will separately screen the titles and abstracts of records acquired potential eligibility which comes from the electronic databases. Full-text screening and data extraction will be conducted afterward independently. Statistical analysis will be conducted using RevMan 5.4 software (Cochrane Collaboration).

RESULTS

What this study will do is evaluate the efficacy and safety of WWXDD in the treatment of WI in order to provide high quality, evidence-based clinical recommendations.

CONCLUSION

This research provides a trusted clinical foundation for the treatment of WI with WWXDD.

Postoperative Delirium in Neurosurgical Patients: Recent Insights into the Pathogenesis

Postoperative delirium (POD) is a complication characterized by disturbances in attention, awareness, and cognitive function that occur shortly after surgery or emergence from anesthesia. Since it occurs prevalently in neurosurgical patients and poses great threats to the well-being of patients, much emphasis is placed on POD in neurosurgical units. However, there are intricate theories about its pathogenesis and limited pharmacological interventions for POD. In this study, we review the recent insights into its pathogenesis, mainly based on studies within five years, and the five dominant pathological theories that account for the development of POD, with the intention of furthering our understanding and boosting its clinical management.

A Four-Probiotic Regime to Reduce Surgical Site Infections in Multi-Trauma Patients

Investigations that focused on the protective role of probiotics against Surgical Site Infections (SSI) in multiple-trauma (MT) patients are generally few, probably due to the complexity of the concept of trauma. We aimed to assess the efficacy of a four-probiotic regime to reduce the incidence of SSI in MT patients, with a brain injury included. MT patients, being intubated and expected to require mechanical ventilation for >10 days, were randomly allocated into placebo (n = 50) or probiotic treatment (n = 53) comprising Lactobacillus acidophilus LA-5 (1.75 × 109 cfu), Lactiplantibacillus plantarum UBLP-40 (0.5 × 109 cfu), Bifidobacterium animalis subsp. lactis BB-12 (1.75 × 109 cfu), and Saccharomycesboulardii Unique-28 (1.5 × 109 cfu) in sachets. All patients received two sachets of placebo or probiotics twice/day for 15 days and were followed-up for 30 days. The operations were classified as neurosurgical, thoracostomies, laparotomies, orthopedics, and others; then, the SSI and the isolated pathogen were registered. A total of 23 (46.0%) and 13 (24.5%) infectious insults in 89 (50 placebo patients) and 88 (53 probiotics-treated) operations (p = 0.022) were recorded, the majority of them relating to osteosynthesis—17 and 8, respectively. The most commonly identified pathogens were Staphylococcus aureus and Acinetobacter baumannii. Our results support published evidence that the prophylactic administration of probiotics in MT patients exerts a positive effect on the incidence of SSI.

The Role of Gut Microbiota—Gut—Brain Axis in Perioperative Neurocognitive Dysfunction

With the aging of the world population and advances in medical and health technology, more and more elderly patients are undergoing anesthesia and surgery, and perioperative neurocognitive dysfunction (PND) is receiving increasing attention. The latest definition of PND, published simultaneously in November 2018 in 6 leading journals in the field of anesthesiology, clarifies that PND includes preoperatively cognitive impairment, postoperative delirium, delayed neurocognitive recovery, and postoperative cognitive dysfunction and meets the diagnostic criteria for neurocognitive impairment in the Diagnostic and Statistical Manual of Mental Disorders -fifth edition (DSM-5). The time frame for PND includes preoperatively and within 12 months postoperatively. Recent studies have shown that gut microbiota regulates central nervous function and behavior through the gut microbiota - gut - brain axis, but the role of the axis in the pathogenesis of PND remains unclear. Therefore, this article reviews the mechanism of the role of gut microbiota-gut-brain axis in PND, so as to help explore reasonable early treatment strategies.

Colorectal microbiota after removal of colorectal cancer

The colonic microbiome has been implicated in the pathogenesis of colorectal cancer (CRC) and intestinal microbiome alterations are not confined to the tumour. Since data on whether the microbiome normalises or remains altered after resection of CRC are conflicting, we studied the colonic microbiota of patients after resection of CRC. We profiled the microbiota using 16S rRNA gene amplicon sequencing in colonic biopsies from patients after resection of CRC (n = 63) in comparison with controls (n = 52), subjects with newly diagnosed CRC (n = 93) and polyps (i = 28). The colonic microbiota after surgical resection remained significantly different from that of controls in 65% of patients. Genus-level profiling and beta-diversity confirmed two distinct groups of patients after resection of CRC: one with an abnormal microbiota similar to that of patients with newly diagnosed CRC and another similar to non-CRC controls. Consumption levels of several dietary ingredients and cardiovascular drugs co-varied with differences in microbiota composition suggesting lifestyle factors may modulate differential microbiome trajectories after surgical resection. This study supports investigation of the colonic microbiota as a marker of risk for development of CRC.

Lactiplantibacillus plantarum AR113 Exhibit Accelerated Liver Regeneration by Regulating Gut Microbiota and Plasma Glycerophospholipid

Emerging evidence indicates that probiotics have been proved to influence liver injury and regeneration. In the present study, the effects of Lactiplantibacillus plantarum AR113 on the liver regeneration were investigated in 70% partial hepatectomy (PHx) rats. Sprague-Dawley (SD) rats were gavaged with L. plantarum AR113 suspensions (1 × 10¹⁰ CFU/mL) both before and after partial hepatectomy. The results showed that L. plantarum AR113 administration 2 weeks before partial hepatectomy can accelerate liver regeneration by increased hepatocyte proliferation and tumor necrosis factor-α (TNF-α), hepatocyte growth factor (HGF), and transforming growth factor-β (TGF-β) expression. Probiotic administration enriched Lactobacillus and Bacteroides and depleted Flavonifractor and Acetatifactor in the gut microbiome. Meanwhile, L. plantarum AR113 showed decline of phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidyl serine (PS), and lysophosphatidyl choline (LysoPC) levels in the serum of the rats after the L. plantarum AR113 administration. Moreover, L. plantarum AR113 treated rats exhibited higher concentrations of L-leucine, L-isoleucine, mevalonic acid, and lower 7-oxo-8-amino-nonanoic acid in plasma than that in PHx. Spearman correlation analysis revealed a significant correlation between changes in gut microbiota composition and glycerophospholipid. These results indicate that L. plantarum AR113 is promising for accelerating liver regeneration and provide new insights regarding the correlations among the microbiome, the metabolome, and liver regeneration.

Gut-Brain Axis: Possible Role of Gut Microbiota in Perioperative Neurocognitive Disorders

Aging is becoming a severe social phenomenon globally, and the improvements in health care and increased health awareness among the elderly have led to a dramatic increase in the number of surgical procedures. Because of the degenerative changes in the brain structure and function in the elderly, the incidence of perioperative neurocognitive disorders (PND) is much higher in elderly patients than in young people following anesthesia/surgery. PND is attracting more and more attention, though the exact mechanisms remain unknown. A growing body of evidence has shown that the gut microbiota is likely involved. Recent studies have indicated that the gut microbiota may affect postoperative cognitive function via the gut-brain axis. Nonetheless, understanding of the mechanistic associations between the gut microbiota and the brain during PND progression remains very limited. In this review, we begin by providing an overview of the latest progress concerning the gut-brain axis and PND, and then we summarize the influence of perioperative factors on the gut microbiota. Next, we review the literature on the relationship between gut microbiota and PND and discuss how gut microbiota affects cognitive function during the perioperative period. Finally, we explore effective early interventions for PND to provide new ideas for related clinical research.

Changes in the gut bacterial communities in colon cancer surgery patients: an observational study

Background

Colon surgery has been shown to modulate the intestinal microbiota. Our objective was to characterize these changes using state-of-the-art next generation sequencing techniques.

Methods

We performed a single-centre prospective observational cohort study to evaluate the changes in the gut microbiota, i.e., taxon distribution, before and after elective oncologic colon surgery in adult patients with different antimicrobial prophylaxis regimens (standard prophylaxis with cefuroxime/metronidazole versus carbapenems for extended-spectrum beta-lactamase-producing Enterobacterales [ESBL-E] carriers). We obtained rectal samples on the day of surgery, intraoperative luminal samples, and rectal or stoma samples 3 days after surgery. We performed metataxonomic analysis based on sequencing of the bacterial 16S rRNA gene marker. Similarities and differences between bacterial communities were assessed using Bray–Curtis similarity, visualised using principal coordinates analysis and statistically tested by PERMANOVA. Comparison of taxa relative abundance was performed using ANCOM.

Results

We included 27 patients between March 27, 2019 and September 17, 2019. The median age was 63.6 years (IQR 56.4–76.3) and 44% were females. Most (81%) patients received standard perioperative prophylaxis as they were not ESBL carriers. There was no significant association between ESBL carriage and differences in gut microbiome. We observed large and significant increases in the genus Enterococcus between the preoperative/intraoperative samples and the postoperative sample, mainly driven by Enterococcus faecalis. There were significant differences in the postoperative microbiome between patients who received standard prophylaxis and carbapenems, specifically in the family Erysipelotrichaceae.

Conclusion

This hypothesis-generating study showed rapid changes in the rectal microbiota following colon cancer surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13099-021-00477-7.

Preoperative Status of Gut Microbiota Predicts Postoperative Delirium in Patients With Gastric Cancer

INTRODUCTION

Post-operative delirium (POD) is a serious complication which occurs after surgery, especially in the elderly undergoing abdominal surgery. Increasing evidence has revealed an association between the gut microbiota and psychological disorders involving the "brain-gut" axis. However, the association between the pathogenesis of POD after abdominal surgery in aging and composition of the gut microbiota remains unclear.

METHODS

Forty patients (≥65 years old) who underwent abdominal surgery were included in the study. Twenty patients had POD, whereas 20 patients did not. POD was diagnosed and assessed using the confusion assessment method (CAM) during the postoperative period. Total DNA fractions were extracted from all fecal samples of patients. 16S rRNA sequencing was performed to determine the composition of the gut microbiota. The quality of the samples was determined by calculating the α- and β-diversities.

RESULTS

The α- and β-diversities indicated that the samples were eligible for detection and comparison. We observed multiple differentially abundant bacteria in patients with and without POD. Generally, Proteobacteria, Enterbacteriaceae, Escherichia shigella, Klebsiella, Ruminococcus, Roseburia, Blautia, Holdemanella, Anaerostipes, Burkholderiaceae, Peptococcus, Lactobacillus, and Dorea were abundant in the POD cohort, whereas Streptococcus equinus and Blautia hominis were abundant in the control cohort. The results of receiver operating characteristic (ROC) curve analysis showed that the area under the curve (AUC) of Escherichia shigella was 0.75. Phenotype prediction showed that the gut microbiota may influence POD by altering the tolerance to oxidative stress.

CONCLUSION

There were significant associations between the pathogenesis of POD and composition of the gut microbiota. Escherichia shigella are promising diagnostic bacterial species for predicting POD onset after abdominal surgery in elderly people.

CLINICAL TRIAL REGISTRATION

http://www.chictr.org.cn/index.aspx, Chinese Clinical Trial Registry ChiCTR200030131.

Probiotics Evaluation in Oncological Surgery: A Systematic Review of 36 Randomized Controlled Trials Assessing 21 Diverse Formulations

BACKGROUND

Objectives were to evaluate probiotics safety and efficacy in oncological surgery.

METHODS

Systematic review methodology guided by Cochrane, PRISMA, SWiM, and CIOMS. Protocol registered on PROSPERO (CRD42018086168).

RESULTS

36 RCTs (on 3305 participants) and 6 nonrandomized/observational studies were included, mainly on digestive system cancers. There was evidence of a beneficial effect on preventing infections, with 70% of RCTs' (21/30) direction of effect favoring probiotics. However, five RCTs (17%) favored controls for infections, including one trial with RR 1.57 (95% CI: 0.79, 3.12). One RCT that changed (balanced) its antibiotics protocol after enrolling some participants had mortality risk RR 3.55 (95% CI: 0.77, 16.47; 7/64 vs. 2/65 deaths). The RCT identified with the most promising results overall administered an oral formulation of Lactobacillus acidophilus LA-5 + Lactobacillus plantarum + Bifidobacterium lactis BB-12 + Saccharomyces boulardii. Methodological quality appraisals revealed an overall substantial risk-of-bias, with only five RCTs judged as low risk-of-bias.

CONCLUSIONS

This large evidence synthesis found encouraging results from most formulations, though this was contrasted by potential harms from a few others, thus validating the literature that "probiotics" are not homogeneous microorganisms. Given microbiome developments and infections morbidity, further high-quality research is warranted using those promising probiotics identified herein.

Postoperative delirium and neurocognitive disorders

PURPOSE OF REVIEW

Postoperative neurocognitive disorders (NCD) are significant causes of morbidity and mortality. In this paper, we will review our understanding and potential management of postoperative NCD.

RECENT FINDINGS

Postoperative delirium, delayed neurocognitive recovery and postoperative cognitive dysfunction (POCD) are recognized as a part of the continuous spectrum of postoperative NCD. Although the pathophysiology is still poorly understood, there is renewed focus on improving neurocognitive outcomes of aging surgical population. Novel methods of neurocognitive screening are developed and research in the prevention and management of NCD has gained traction.

SUMMARY

A spectrum of NCD exists in surgical patients ranging from postoperative delirium, delayed neurocognitive recovery, and POCD. Identification of patients at-risk for developing NCD can help target appropriate perioperative intervention. Also, specialized care teams and the implementation of standardized protocols are crucial for the successful management perioperative NCD. Finally, large, randomized, multicenter studies are needed to confirm benefits of preventive and treatment strategies.

Current Insights: The Impact of Gut Microbiota on Postoperative Complications in Visceral Surgery-A Narrative Review

Postoperative complications are a major problem occurring in up to 50% of patients undergoing major abdominal surgery. Occurrence of postoperative complications is associated with a significantly higher morbidity and mortality in affected patients. The most common postoperative complications are caused by an infectious genesis and include anastomotic leakage in case of gastrointestinal anastomosis and surgical site infections. Recent research highlighted the importance of gut microbiota in health and disease. It is plausible that the gut microbiota also plays a pivotal role in the development of postoperative complications. This narrative review critically summarizes results of recent research in this particular field. The review evaluates the role of gut microbiota alteration in postoperative complications, including postoperative ileus, anastomotic leakage, and surgical site infections in visceral surgery. We tried to put a special focus on a potential diagnostic value of pre- and post-operative gut microbiota sampling showing that recent data are inhomogeneous to identify a high-risk microbial profile for development of postoperative complications.

Pain in the Cancer Survivor

Recent decades have demonstrated significant strides in cancer screening, diagnostics and therapeutics. As such there have been dramatic changes in survival following a diagnosis of cancer.

The Role of Gut Microbiota in Overcoming Resistance to Checkpoint Inhibitors in Cancer Patients: Mechanisms and Challenges

The introduction of immune checkpoint inhibitors has constituted a major revolution in the treatment of patients with cancer. In contrast with the traditional cytotoxic therapies that directly kill tumor cells, this treatment modality enhances the ability of the host’s immune system to recognize and target cancerous cells. While immune checkpoint inhibitors have been effective across multiple cancer types, overcoming resistance remains a key area of ongoing research. The gut microbiota and its role in cancer immunosurveillance have recently become a major field of study. Gut microbiota has been shown to have direct and systemic effects on cancer pathogenesis and hosts anti-tumor immune response. Many studies have also shown that the host microbiota profile plays an essential role in the response to immunotherapy, especially immune checkpoint inhibitors. As such, modulating this microbial environment has offered a potential path to overcome the resistance to immune checkpoint inhibitors. In this review, we will talk about the role of microbiota in cancer pathogenesis and immune-system activity. We will also discuss preclinical and clinical studies that have increased our understanding about the roles and the mechanisms through which microbiota influences the response to treatment with immune checkpoint inhibitors.

Association of Habitual Preoperative Dietary Fiber Intake With Complications After Colorectal Cancer Surgery

IMPORTANCE

Postoperative complications are associated with increased morbidity and mortality among patients with colorectal cancer. As a modifiable factor associated with gut health, dietary fiber intake is of interest with regard to the risk of complications after surgery for colorectal cancer.

OBJECTIVE

To examine the association between preoperative dietary fiber intake and risk of complications after surgery for colorectal cancer.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from the Colorectal Longitudinal, Observational Study on Nutritional and Lifestyle Factors (COLON) study, which recruited adult patients with colorectal cancer at any stage at diagnosis from 11 hospitals in the Netherlands between August 2010 and December 2017. The present study included patients with stage I to IV colorectal cancer who underwent elective abdominal surgery. Data were analyzed between December 2019 and September 2020.

EXPOSURES

Habitual dietary fiber intake was assessed at diagnosis using a 204-item food frequency questionnaire.

MAIN OUTCOMES AND MEASURES

Any complications, surgical complications, and anastomotic leakage occurring during the 30 days after surgery for colorectal cancer. The association between fiber intake and risk of postoperative complications was assessed using logistic regression analyses. Additional analyses stratified by sex, tumor location, and fiber source were performed.

RESULTS

Among the 1399 patients included in the analysis, the median age at inclusion was 66 years (interquartile range, 61-72 years) and 896 (64%) were men. Any complications occurred in 397 patients (28%), and surgical complications occurred in 235 patients (17%). Of 1237 patients with an anastomosis, 67 (5%) experienced anastomotic leakage. Higher dietary fiber intake (per 10 g per day) was associated with a lower risk of any complications (odds ratio [OR], 0.75; 95% CI, 0.62-0.92) and surgical complications (OR, 0.76; 95% CI, 0.60-0.97), whereas no association with anastomotic leakage was found (OR, 0.97; 95% CI, 0.66-1.43). Among women, higher dietary intake was associated with any complications (OR, 0.64; 95% CI, 0.44-0.94), whereas there was no association among men (OR, 0.79; 95% CI, 0.63-1.01). Fiber intake from vegetables (per 1 g per day) was inversely associated with any (OR, 0.90; 95% CI, 0.83-0.99) and surgical (OR, 0.87; 95% CI, 0.78-0.97) complications.

CONCLUSIONS AND RELEVANCE

In this cohort study, higher habitual dietary fiber intake before surgery was associated with a lower risk of postoperative complications among patients with colorectal cancer. The findings suggest that improving preoperative dietary fiber intake may be considered in future prehabilitation programs for patients undergoing surgery for colorectal cancer.

Harnessing the Microbiome to Optimize Surgical Outcomes in the COVID-19 Era

In this era of testing uncertainties, changing guidelines, and incomplete knowledge, "clearing" patients for surgery in the time of SARS-COVID-19 has been met with various challenges. Efforts to increase patient fitness have long been at the forefront of surgical practicing guidelines, but the current climate requires a renewed sense of focus on these measures. It is essential to understand how dietary history, previous antibiotic exposure, and baseline microbiota can inform and optimize preoperative and postoperative management of the surgical patient in the time of COVID-19. This piece focuses on the clinical, molecular, and physiologic dynamics that occur in preparing patients for surgery during COVID-19, considering the physiologic stress inherent in the procedure itself and the importance of specialized perioperative management approaches. COVID-19 has created a renewed sense of urgency to maintain our discipline in implementing those practices that have long been confirmed to be beneficial to patient outcome. This practice, along with a renewed interest in understanding how the gut microbiome is affected by the confinement, social distancing, etc., due to the COVID pandemic, is ever more important. Therefore, here we discuss the microbiome's role as a defense against viral infection and its potential for reactivation during the process of surgery as the next frontier for surgical advancement.

Effects of Sevoflurane Inhalation Anesthesia on the Intestinal Microbiome in Mice

In recent years, more and more attention has been paid to intestinal microbiome. Almost all operations will go through the anesthesia process, but it is not clear whether the intervention of anesthesia alone will affect the change in the intestinal microbiome. The purpose of this study was to verify the effect of sevoflurane inhalation anesthesia on the intestinal microbiome. The animal in the experimental group was used to provide sevoflurane inhalation anesthesia for 4 hours. The control group was not intervened. The feces of the experimental group and the control group were collected on the 1st, 3rd, 7th and 14th days after anesthesia. Sevoflurane inhalation anesthesia will cause changes in the intestinal microbiome of mice. It appears on the 1st day after anesthesia and is most obvious on the 7th day. The specific manifestation is that the abundance of microbiome and the diversity of the microbiome is reduced. At the same time, Untargeted metabonomics showed that compared with the control group, the experimental group had more increased metabolites related to the different microbiome, among which 5-methylthioadenosine was related to the central nervous system. Subsequently, the intestinal microbiome diversity of mice showed a trend of recovery on the 14th day. At the genus level, the fecal samples obtained on the 14th day after anesthesia exhibited significantly increased abundances of Bacteroides, Alloprevotella, and Akkermansia and significantly decreased abundances of Lactobacillus compared with the samples obtained on the 1st day after anesthesia. However, the abundance of differential bacteria did not recover with the changing trend of diversity. Therefore, we believe that sevoflurane inhalation anesthesia is associated with changes in the internal microbiome and metabolites, and this change may be completed through the brain-gut axis, while sevoflurane inhalation anesthesia may change the intestinal microbiome for as long as 14 days or longer.

An altered composition of fecal microbiota, organic acids, and the effect of probiotics in the guinea pig model of postoperative ileus

BACKGROUND

The aim of this study is to investigate the altered composition of fecal microbiota, organic acids, and the effect of probiotics in the guinea pig model of the postoperative ileus (POI).

METHODS

A laparotomy with cecal manipulation was performed to induce POI in guinea pigs. Fecal pellets were collected before the operation (the baseline) and 1, 3, and 5 days after the operation. The extracted fecal DNA was amplified and sequenced using the Illumina MiSeq sequencing system. The same POI procedures were performed after oral pretreatment of the probiotics for 7 days before operation. The effect of the probiotics on the selected taxa and fecal acetate were evaluated, as were the butyrate levels. The colonic transit was assessed by measurement of the fecal pellet output.

KEY RESULTS

The communities of the baseline and POI groups indicated significantly distinct composition. The genera Bifidobacterium and Lactobacillus were more abundant in the baseline group compared with the POI groups, and Bacteroides and Blautia were more abundant in the POI groups. Decreased abundances of the species Bifidobacterium bifidum and Bifidobacterium longum after the POI procedure were significantly increased in the probiotics group. The decreased fecal butyrate level after the POI procedure was significantly increased, and colonic transit was significantly improved in the probiotics group.

CONCLUSIONS AND INFERENCES

POI induces gut bacterial dysbiosis. Moreover, pretreatment of probiotics before operation restores the beneficial bacterial species, butyrate production, and bowel movement. The modulation of gut microbiota may help the treatment and prevention of POI.

Association between postoperative changes in the gut microbiota and pseudopsia after cardiac surgery: prospective observational study

Background

Delirium after cardiac surgery affects mortality, but the mechanism remains unclear. Previous studies have reported gut microbiota are associated with brain activity. Systemic inflammation and antibiotics can damage the gut microbiota after cardiac surgery. We aimed to investigate changes in the gut microbiota and the association between the gut microbiota and delirium after cardiac surgery.

Methods

Twenty-one patients who underwent cardiac surgery were enrolled. Microbiota counts and fecal organic acid concentrations were measured in fecal samples harvested before surgery, just after surgery, and before discharge. To quantify the microbiota, we extracted total RNA fractions and examined gut microbiota composition using 16S and 23S rRNA-targeted quantitative-reverse Transcription-PCR. Postoperative delirium, insomnia, and pseudopsia were assessed for 1 week. Postoperative total bacterial counts changed significantly from 10.2 ± 0.2 log₁₀ cells/g of feces to 9.8 ± 0.5 in the first postoperative samples (p = 0.003) and 10.0 ± 0.4 in the samples before discharge (p = 0.039). Fecal pH was 6.9 ± 0.6 before surgery and 7.4 ± 0.7 in the first postoperative samples (p = 0.001). Postoperative Staphylococcus and Pseudomonas counts were significantly higher in patients with postoperative pseudopsia than in patients without pseudopsia (3.2 ± 1.3 vs. 5.4 ± 0.9; p = 0.012 and 1.7 ± 0.8 vs. 4.6 ± 2.7; p = 0.001).

Conclusions

Total bacterial counts were significantly lower after surgery and until discharge. Fecal pH was significantly higher than preoperative levels. Staphylococcus and Pseudomonas counts were significantly higher in patients with postoperative pseudopsia.

Increase in surgical site infections caused by gram-negative bacteria in warmer temperatures: Results from a retrospective observational study

OBJECTIVE

Surgical site infections (SSIs) occur more frequently during periods of warmer temperatures. We aimed to investigate for which pathogens this association is particularly strong.

DESIGN

A retrospective observational study was conducted.

METHODS

Data from the SSI-module of the German nosocomial infection surveillance system between 2000 and 2016 were linked with data from the German Meteorological Service. Patient- and procedure-related data were associated with monthly aggregated meteorological data. Due to high correlation with other meteorological parameters, we focused on the outside temperature. Adjusted odds ratios were calculated for SSI rates relating to temperature. SSIs were stratified by pathogen. A P value of <.05 was considered significant.

RESULTS

Altogether, 2,004,793 procedures resulting in 32,118 SSIs were included. Generally, warmer temperatures were associated with a higher SSI risk, especially for SSIs with gram-negative pathogens. This association was particularly prominent for Acinetobacter spp, Pseudomonas aeruginosa, and certain Enterobacteriaceae. Per additional 1°C, we observed a 6% increase in the SSI risk for Acinetobacter spp and a 4% increase for Enterobacter spp. Superficial SSIs with Acinetobacter spp were 10 times more likely to occur when comparing surgeries in months with mean temperatures of ≥20°C to mean temperatures of <5°C.

CONCLUSIONS

Higher temperatures were associated with increased SSI rates caused by gram-negative bacteria. Future SSI prevention measures should consider this aspect. Underlying shifts in microbiome composition due to climate factors should be included in further analyses. Given the expected rise of global temperatures until the end of the century, this topic has relevance from multiple perspectives.

Molecularly imprinted sol-gel/Au@Ag core-shell nano-urchin localized surface plasmon resonance sensor designed in reflection mode for detection of organic acid vapors

A molecularly imprinted sol-gel (MISG)/Au@Ag core-shell NU sensor is proposed for organic vapor detection in an optical fiber-based reflection mode. The compact structure design of the system in the reflection model is promising for practical use as a portable and rapid responsivity sensing probe. Volatile organic acids (OAs) are analogs to biogenetic volatile organic vapors related to specific human diseases. Here, Au@Ag core-shell nano-urchins exhibiting branched tips were synthesized and deposited on indium tin oxide (ITO) glass in small dimer and trimmer clusters to generate an enhanced electric field. A MISG solution was then spin-coated on the substrate to fabricate MISG-LSPR sensors, and three types of MISGs were developed for the detection of hexanoic acid, heptanoic acid and octanoic acid. The normalized spectral response indicated selectivity of the MISG-LSPR sensors for the corresponding template OAs. With Native Bayes and linear discriminant analysis of the sensor responses, where the latter were detected by the proposed system, single- and mixed-OA vapors could be classified into separate clusters. This signified that the proposed MISG-LSPR sensor can be applied toward pattern recognition of single vapors or multiple vapor mixtures.

Pathomechanisms of Non-Traumatic Acute Brain Injury in Critically Ill Patients

Delirium, an acute alteration in mental status characterized by confusion, inattention and a fluctuating level of arousal, is a common problem in critically ill patients. Delirium prolongs hospital stay and is associated with higher mortality. The pathophysiology of delirium has not been fully elucidated. Neuroinflammation and neurotransmitter imbalance seem to be the most important factors for delirium development. In this review, we present the most important pathomechanisms of delirium in critically ill patients, such as neuroinflammation, neurotransmitter imbalance, hypoxia and hyperoxia, tryptophan pathway disorders, and gut microbiota imbalance. A thorough understanding of delirium pathomechanisms is essential for effective prevention and treatment of this underestimated pathology in critically ill patients.

Gut Microbiota Dysbiosis as a Target for Improved Post-Surgical Outcomes and Improved Patient Care: A Review of Current Literature

ABSTRACT

Critical illness results in significant changes in the human gut microbiota, leading to the breakdown of the intestinal barrier function, which plays a role in the pathogenesis of multiple organ dysfunction. Patients with sepsis/acute respiratory distress syndrome (ARDS) have a profoundly distorted intestinal microbiota rhythm, which plays a considerable role in the development of gut-derived infections and intestinal dysbiosis. Despite recent medical developments, postsurgical complications are associated with a high morbidity and mortality rate. Bacterial translocation, which is the movement of bacteria and bacterial products across the intestinal barrier, was shown to be a mechanism behind sepsis. Current research is focusing on a solution by addressing significant factors that contribute to intestinal dysbiosis, which subsequently leads to multiple organ failure and, thus, mortality. It may, however, be challenging to manipulate the microbiota in critically ill patients for enhanced therapeutic gain. Probiotic manipulation is advantageous for maintaining the gut-barrier defense and for modulating the immune response. Based on available published research, this review aims to address the application of potential strategies in the intensive care unit, supplemented with current therapeutics by the administration of probiotics, prebiotics, and fecal microbiota transplant, to reduce post-surgical complications of sepsis/ARDS in critically ill patients.

Influence of gastrectomy for gastric cancer treatment on faecal microbiome and metabolome profiles

OBJECTIVE

Recent evidence points to the gut microbiome's involvement in postoperative outcomes, including after gastrectomy. Here, we investigated the influence of gastrectomy for gastric cancer on the gut microbiome and metabolome, and how it related to postgastrectomy conditions.

DESIGN

We performed shotgun metagenomics sequencing and capillary electrophoresis time-of-flight mass spectrometry-based metabolomics analyses on faecal samples collected from participants with a history of gastrectomy for gastric cancer (n=50) and compared them with control participants (n=56).

RESULTS

The gut microbiota in the gastrectomy group showed higher species diversity and richness (p<0.05), together with greater abundance of aerobes, facultative anaerobes and oral microbes. Moreover, bile acids such as genotoxic deoxycholic acid and branched-chain amino acids were differentially abundant between the two groups (linear discriminant analysis (LDA) effect size (LEfSe): p<0.05, q<0.1, LDA>2.0), as were also Kyoto Encyclopedia of Genes and Genomes modules involved in nutrient transport and organic compounds biosynthesis (LEfSe: p<0.05, q<0.1, LDA>2.0).

CONCLUSION

Our results reveal alterations of gut microbiota after gastrectomy, suggesting its association with postoperative comorbidities. The multi-omic approach applied in this study could complement the follow-up of patients after gastrectomy.

Trauma of major surgery: A global problem that is not going away

Globally, a staggering 310 million major surgeries are performed each year; around 40 to 50 million in USA and 20 million in Europe. It is estimated that 1–4% of these patients will die, up to 15% will have serious postoperative morbidity, and 5–15% will be readmitted within 30 days. An annual global mortality of around 8 million patients places major surgery comparable with the leading causes of death from cardiovascular disease and stroke, cancer and injury. If surgical complications were classified as a pandemic, like HIV/AIDS or coronavirus (COVID-19), developed countries would work together and devise an immediate action plan and allocate resources to address it. Seeking to reduce preventable deaths and post-surgical complications would save billions of dollars in healthcare costs. Part of the global problem resides in differences in institutional practice patterns in high- and low-income countries, and part from a lack of effective perioperative drug therapies to protect the patient from surgical stress. We briefly review the history of surgical stress and provide a path forward from a systems-based approach. Key to progress is recognizing that the anesthetized brain is still physiologically ‘awake’ and responsive to the sterile stressors of surgery. New intravenous drug therapies are urgently required after anesthesia and before the first incision to prevent the brain from switching to sympathetic overdrive and activating secondary injury progression such as hyperinflammation, coagulopathy, immune activation and metabolic dysfunction. A systems-based approach targeting central nervous system-mitochondrial coupling may help drive research to improve outcomes following major surgery in civilian and military medicine.

Effects of PrObiotics on the Symptoms and Surgical ouTComes after Anterior REsection of Colon Cancer (POSTCARE): A Randomized, Double-Blind, Placebo-Controlled Trial

We investigated microbiota changes following surgical colon cancer resection and evaluate effects of probiotics on microbiota and surgical recovery. This randomized double-blind trial was performed at four medical centers in South Korea. Of 68 patients expected to undergo anterior sigmoid colon cancer resection, 60 were eligible, of whom 29 and 31 received probiotics and placebo, respectively, for four weeks, starting at one week preoperatively. Third- and/or fourth-week information on anterior resection syndrome (ARS), inflammatory markers, and quality of life was obtained. Stool sample analysis was conducted after randomization and bowel preparation and at three and four postoperative weeks. Bacteria were categorized into Set I (with probiotic effects) and II (colon cancer-associated). The probiotic group’s ARS score showed an improving trend (p = 0.063), particularly for flatus control (p = 0.030). Serum zonulin levels significantly decreased with probiotics. Probiotic ingestion resulted in compositional changes in gut microbiota; greater increases and decreases in Set I and II bacteria, respectively, occurred with probiotics. Compositional increase in Set I bacteria was associated with reduced white blood cells, neutrophils, neutrophil-lymphocyte ratio, and zonulin. Bifidobacterium composition was negatively correlated with zonulin levels in the probiotic group. Probiotics improved postoperative flatus control and modified postoperative changes in microbiota and inflammatory markers.

Modulating the microbiome to improve therapeutic response in cancer

Although novel therapies, including immunotherapy, have dramatically improved outcomes for many patients with cancer, overall outcomes are heterogeneous and existing biomarkers do not reliably predict response. To date, predictors of response to cancer therapy have largely focused on tumour-intrinsic features; however, there is growing evidence that other host factors (eg, host genomics and the microbiome) can substantially affect therapeutic response. The microbiome, which refers to microbiota within a host and their collective genomes, is becoming increasingly recognised for its influence on host immunity, as well as therapeutic responses to cancer treatment. Importantly, microbiota can be modified via several different strategies, affording new angles in cancer treatment to improve outcomes. In this Review, we examine the evidence on the role of the microbiome in cancer and therapeutic response, factors that influence and shape host microbiota, strategies to modulate the microbiome, and present key unanswered questions to be addressed in ongoing and future research.

Gut microbiota in surgical and critically ill patients

Microbiota-defined as a collection of microbial organisms colonising different parts of the human body-is now recognised as a pivotal element of human health, and explains a large part of the variance in the phenotypic expression of many diseases. A reduction in microbiota diversity, and replacement of normal microbes with non-commensal, pathogenic or more virulent microbes in the gastrointestinal tract-also known as gut dysbiosis-is now considered to play a causal role in the pathogenesis of many acute and chronic diseases. Results from animal and human studies suggest that dysbiosis is linked to cardiovascular and metabolic disease through changes to microbiota-derived metabolites, including trimethylamine-N-oxide and short-chain fatty acids. Dysbiosis can occur within hours of surgery or the onset of critical illness, even without the administration of antibiotics. These pathological changes in microbiota may contribute to important clinical outcomes, including surgical infection, bowel anastomotic leaks, acute kidney injury, respiratory failure and brain injury. As a strategy to reduce dysbiosis, the use of probiotics (live bacterial cultures that confer health benefits) or synbiotics (probiotic in combination with food that encourages the growth of gut commensal bacteria) in surgical and critically ill patients has been increasingly reported to confer important clinical benefits, including a reduction in ventilator-associated pneumonia, bacteraemia and length of hospital stay, in small randomised controlled trials. However, the best strategy to modulate dysbiosis or counteract its potential harms remains uncertain and requires investigation by a well-designed, adequately powered, randomised controlled trial.

Role of preoperative gut microbiota on colorectal anastomotic leakage: preliminary results

BACKGROUND

The dysbiosis is defined as a disturbed symbiotic relationship between microbiota and the host and can cause a pro-inflammatory imbalance impairing the healing process at anastomotic level. The aim of this study is to detect, in fecal samples collected in the preoperative time, a peculiar microbiota composition that could predict the onset of colorectal anastomotic leakage.

MATERIALS AND METHODS

We compared gut microbiota of healthy patients (Group A) and patients with colorectal cancer eligible for surgery (Group B). Group B was divided into patients who developed anastomotic leak (Group BL) and patients who had uneventful recovery (Group BNL). Stool samples were collected before surgery and after neoadjuvant treatment.

RESULTS

We analyzed stool samples from 48 patients, 27 belonging to Group A and 21 to Group B. In Group B, five patients developed anastomotic leakage (Group BL). Compared to healthy subjects, Group B showed a moderate increase of Bacteroidetes and Proteobacteria, a moderate reduction of Firmicutes and Actinobacteria, and a statistically significant reduction of Faecalibacterium prausnitzii. Group BL patients showed an array of bacterial species which promoted dysbiosis, such as Acinetobacter lwoffii and Hafnia alvei. Group BNL patients showed that bacterial species like Faecalibacterium prausnitzii and Barnesiella intestinihominis have a protective function.

CONCLUSIONS

The bacterial flora in subjects with colorectal cancer is statistically different compared to healthy patients. The presence of preoperative aggressive bacteria and the lack of protective strains has strengthened the hypothesis that a peculiar microbiota composition could represent a risk factor for the occurrence of anastomotic leakage.

Appendectomy, cholecystectomy and diagnostic laparoscopy conducted before pregnancy and risk of adverse birth outcomes: a nationwide registry-based prevalence study 1996-2015

Background

Non-obstetric surgery conducted during pregnancy may increase the risk of adverse birth outcomes like small for gestational age, preterm birth, and miscarriage. Mechanisms are unclear but possibly longer lasting. We examined whether appendectomy, cholecystectomy and diagnostic laparoscopy conducted before pregnancy affect these outcomes.

Methods

This nationwide Danish prevalence study included all pregnancies during 1996–2015 that had an appendectomy, cholecystectomy or diagnostic laparoscopy registered before last menstrual period in the years 1992–2015. We excluded pregnancies with surgery and categorized pre-pregnancy surgery according to timing (0–11, 12–23, and 24+ months before last menstrual period). Outcomes were small for gestational age, late preterm birth (32–37 weeks), early preterm birth (22–31 weeks) and miscarriage (7–21 weeks). We computed absolute risks and used logistic regression comparing pregnancies with surgery 0–11 or 12–23 to 24+ months before last menstrual period, computing odds ratios for each outcome, adjusting for maternal age and smoking.

Results

We identified 15,939 pregnancies with appendectomy, 12,869 pregnancies with cholecystectomy and 19,330 pregnancies with diagnostic laparoscopy. The absolute risk of small for gestational age was 2.2% for patients with appendectomy 0–11 months before last menstrual period, 3.2% 12–23 months before compared with 2.2% when appendectomy was conducted more than 24 months before (adjusted OR 0.95 (95% CI; 0.65 to 1.31) and 1.37(95% CI;1.00 to 1.86). For early preterm birth, the absolute risks were 0.7, 0.5 and 0.8%, for late preterm birth 4.8, 4.4 and 4.7% and for miscarriage 5.7, 6.2 and 5.4%.We observed similar results for cholecystectomy. For diagnostic laparoscopy 0–11 months before pregnancy we found increased risks of small for gestational age (4.0, 2.8 and 2.6%) and late preterm birth (5.9, 5.0 and 4.8%).

Conclusions

We found no increased risk of adverse birth outcomes among pregnancies with appendectomy or cholecystectomy conducted within 2 years before pregnancy compared to more than 2 years before pregnancy. The increased risks 0–11 months after diagnostic laparoscopy are likely explained by confounding by underlying indication. It appears safe to become pregnant any time following appendectomy and cholecystectomy, but, probably depending on indication, attention should be payed 0–11 months after diagnostic laparoscopy.

Non-obstetric abdominal surgery during pregnancy and birth outcomes: A Danish registry-based cohort study

INTRODUCTION

Surgery during pregnancy may increase the risk of adverse birth outcomes. In this nationwide registry-based cohort study including women aged 15-54 years with singleton birth or miscarriage, we examined the association between non-obstetric abdominal surgery during pregnancy and the birth outcomes small-for-gestational-age (SGA), preterm birth, and miscarriage.

MATERIAL AND METHODS

The study used data on births or miscarriages from the large national Danish registries in 1997-2015. We calculated absolute risks and risk differences for the main outcomes and used Cox regression analysis with non-obstetric abdominal surgery as a time-varying exposure, adjusting for maternal age, year of last menstrual period, major abdominal surgery before pregnancy, maternal smoking status, rheumatoid arthritis, diabetes and inflammatory bowel disease. Our main outcome measures were risks and hazard ratios (HRs) for SGA, very preterm or preterm birth, and miscarriage after gestational week 7 overall, stratified by calendar year, and, for SGA, trimester of pregnancy. Finally, absolute risk of miscarriage stratified by time since surgery.

RESULTS

Absolute risks in surgically treated vs untreated were 3.4% vs 2.7% for SGA (adjusted HR 1.3, 95% CI 1.1-1.5), 2.2% vs 0.8% for very preterm birth (adjusted HR 2.8, 95% CI 2.2-3.5), 8.3% vs 4.3% for preterm birth (adjusted HR 2.1, 95% CI 1.9-2.3), and 8.2% vs 6.1% for miscarriage (adjusted HR 3.1, 95% CI 2.7-3.5). For miscarriage, the risk was highest the first week after surgery and levelled out after 2 weeks.

CONCLUSIONS

Surgery during pregnancy is associated with an increased risk of SGA, very preterm birth, preterm birth and miscarriage, and the risk of miscarriage is highest the first week after surgery.

Naturopathic Treatment and Complementary Medicine in Surgical Practice

BACKGROUND

Many patients in Germany use naturopathic treatments and complementary medicine. Surveys have shown that many also use them as a concomitant treatment to surgery.

METHODS

Multiple databases were systematically searched for systematic reviews, controlled trials, and experimental studies concerning the use of naturopathic treatments and complementary medicine in the management of typical post-operative problems (PROSPERO CRD42018095330).

RESULTS

Of the 387 publications identified by the search, 76 fulfilled the inclusion criteria. In patients with abnormal gastrointestinal activity, acupuncture can improve motility, ease the passing of flatus, and lead to earlier defecation. Acupuncture and acupressure can reduce postoperative nausea and vomiting, as well as pain. More-over,aromatherapy and music therapy seem to reduce pain, stress and anxiety and to improve sleep. Further studies are needed to determine whether phytotherapeutic treatments are effective for the improvement of gastrointestinal function or the reduction of stress. It also remains unclear whether surgical patients can benefit from the methods of mind body medicine.

CONCLUSION

Certain naturopathic treatments and complementary medical methods may be useful in postoperative care and deserve more intensive study. In the publications consulted for this review, no serious side effects were reported.

Post-surgical intestinal dysbiosis: use of an innovative mixture (Lactobacillus plantarum LP01, Lactobacillus lactis subspecies cremoris LLC02, Lactobacillus delbrueckii LDD01)

Abdominal surgery represents a high risk for hospital-acquired infections and complication that may compromise the surgery outcome. Patients with recent abdominal surgery have an intestinal dysbiosis. There is evidence that probiotics may counterbalance the impaired microbiota. Therefore, the current survey evaluated the efficacy and safety of Abincol®, an oral nutraceutical containing a probiotic mixture with Lactobacillus plantarum LP01 (1 billion of living cells), Lactobacillus lactis subspecies cremoris LLC02 (800 millions of living cells), and Lactobacillus delbrueckii LDD01 (200 millions of living cells), in 612 outpatients (344 males and 268 females, mean age 58 years) undergoing digestive surgery. Patients took 1 stick/daily for 8 weeks. Abincol® significantly diminished the presence and the severity of intestinal symptoms and improved stool form. In conclusion, the current survey suggests that Abincol® may be considered an effective and safe therapeutic option in the management of patients undergoing digestivesurgery.

The Role of the Small Bowel in Unintentional Weight Loss after Treatment of Upper Gastrointestinal Cancers

Upper gastrointestinal (GI) cancers are responsible for significant mortality and morbidity worldwide. To date, most of the studies focused on the treatments’ efficacy and post-treatment survival rate. As treatments improve, more patients survive long term, and thus the accompanying complications including unintentional weight loss are becoming more important. Unintentional weight loss is defined as >5% of body weight loss within 6–12 months. Malignancies, particularly GI cancers, are diagnosed in approximately 25% of patients who present with unintentional weight loss. Whereas some recent studies discuss pathophysiological mechanisms and new promising therapies of cancer cachexia, there is a lack of studies regarding the underlying mechanism of unintentional weight loss in patients who are tumor free and where cancer cachexia has been excluded. The small bowel is a central hub in metabolic regulation, energy homeostasis, and body weight control throughout the microbiota-gut-brain axis. In this narrative review article, the authors discussed the impacts of upper GI cancers’ treatment modalities on the small bowel which may lead to unintentional weight loss and some new promising therapeutic agents to treat unintentional weight loss in long term survivors after upper GI operations with curative intent.

Abnormal composition of gut microbiota contributes to delirium-like behaviors after abdominal surgery in mice

Aims

Anesthesia and surgery can cause delirium‐like symptoms postoperatively. Increasing evidence suggests that gut microbiota is a physiological regulator of the brain. Herein, we investigated whether gut microbiota plays a role in postoperative delirium (POD).

Methods

Mice were separated into non‐POD and POD phenotypes after abdominal surgery by applying hierarchical clustering analysis to behavioral tests. Fecal samples were collected, and 16S ribosomal RNA gene sequencing was performed to detect differences in gut microbiota composition among sham, non‐POD, and POD mice. Fecal bacteria from non‐POD and POD mice were transplanted into antibiotics‐induced pseudo‐germ‐free mice to investigate the effects on behaviors.

Results

α‐diversity and β‐diversity indicated differences in gut microbiota composition between the non‐POD and POD mice. At the phylum level, the non‐POD mice had significantly higher levels of Tenericutes, which were not detected in the POD mice. At the class level, levels of Gammaproteobacteria were higher in the POD mice, whereas the non‐POD mice had significantly higher levels of Mollicutes, which were not detected in the POD mice. A total of 20 gut bacteria differed significantly between the POD and non‐POD mice. Interestingly, the pseudo‐germ‐free mice showed abnormal behaviors prior to transplant. The pseudo‐germ‐free mice that received fecal bacteria transplants from non‐POD mice but not from POD mice showed improvements in behaviors.

Conclusions

Abnormal gut microbiota composition after abdominal surgery may contribute to the development of POD. A therapeutic strategy that targets gut microbiota could provide a novel alterative for POD treatment.

A Systematic Review, Meta-Analysis, and Meta-Regression Evaluating the Efficacy and Mechanisms of Action of Probiotics and Synbiotics in the Prevention of Surgical Site Infections and Surgery-Related Complications

Intestinal microbiota play an important role in the pathogenesis of surgical site infections (SSIs) and other surgery-related complications (SRCs). Probiotics and synbiotics were found to lower the risk of surgical infections and other surgery-related adverse events. We systematically reviewed the approach based on the administration of probiotics and synbiotics to diminish SSIs/SRCs rates in patients undergoing various surgical treatments and to determine the mechanisms responsible for their effectiveness. A systematic literature search in PubMed/MEDLINE/Cochrane Central Register of Controlled Trials from the inception of databases to June 2018 for trials in patients undergoing surgery supplemented with pre/pro/synbiotics and randomized to the intervention versus placebo/no treatment and reporting on primarily: (i) putative mechanisms of probiotic/symbiotic action, and secondarily (ii) SSIs and SRCs outcomes. Random-effect model meta-analysis and meta-regression analysis of outcomes was done. Thirty-five trials comprising 3028 adult patients were included; interventions were probiotics (n = 16) and synbiotics (n = 19 trials). We found that C-reactive protein (CRP) and Interleukin-6 (IL-6) were significantly decreased (SMD: -0.40, 95% CI [-0.79, -0.02], p = 0.041; SMD: -0.41, 95% CI [-0.70, -0.02], p = 0.006, respectively) while concentration of acetic, butyric, and propionic acids were elevated in patients supplemented with probiotics (SMD: 1.78, 95% CI [0.80, 2.76], p = 0.0004; SMD: 0.67, 95% CI [0.37, -0.97], p = 0.00001; SMD: 0.46, 95% CI [0.18, 0.73], p = 0.001, respectively). Meta-analysis confirmed that pro- and synbiotics supplementation was associated with significant reduction in the incidence of SRCs including abdominal distention, diarrhea, pneumonia, sepsis, surgery site infection (including superficial incisional), and urinary tract infection, as well as the duration of antibiotic therapy, duration of postoperative pyrexia, time of fluid introduction, solid diet, and duration of hospital stay (p < 0.05). Probiotics and synbiotics administration counteract SSIs/SRCs via modulating gut-immune response and production of short chain fatty acids.