Recent Anti-Microbial Exposure Is Associated with More Complications after Elective Surgery

Tailored Pre-Operative Antibiotic Prophylaxis to Prevent Post-Operative Surgical Site Infections in General Surgery

The average American today undergoes three inpatient and two outpatient surgical procedures during one's life, each of which carries with it a risk of post-operative infection. It has long been known that post-operative infections cause significant morbidity in the immediate peri-operative period, but recent evidence suggests that they can have long-term consequences as well, increasing a patient's risk of infectious complications in unrelated surgeries performed months or even years later. While there are several theories on the origin of this association, including bacterial colonization of a post-operative infectious wound site, antimicrobial resistance from curative courses of antibiotics, subclinical immunosuppression, or the creation of an inflammatory "pathobiome" following an infectious insult, it is ultimately still unclear why patients who experience a single post-operative infection seem to be at a significantly higher risk of experiencing subsequent ones. Regardless, this association has significant implications for the routine use of pre-operative antibiotic prophylaxis. Indeed, while the prescription of antibiotics pre-operatively has dramatically reduced the rate of post-operative infections, the chosen prophylaxis regimens are typically standardized according to national guidelines, are facing increasing antimicrobial resistance patterns, and have been unable to reduce the risk of post-operative infection to acceptably low levels for certain surgeries. As a result, some clinicians have speculated that tailoring pre-operative antibiotic prophylaxis according to a patient's prior infectious and operative history could improve efficacy and further reduce the rate of post-operative infections. The purpose of this review is to describe the evidence for the link between multiple post-operative infections and explore the efficacy of individualized pre-operative prophylaxis.

Gut Microbiome-Based Therapeutics in Critically Ill Adult Patients-A Narrative Review

The gut microbiota plays a crucial role in the human microenvironment. Dysbiosis of the gut microbiota is a common pathophysiological phenomenon in critically ill patients. Therefore, utilizing intestinal microbiota to prevent complications and improve the prognosis of critically ill patients is a possible therapeutic direction. The gut microbiome-based therapeutics approach focuses on improving intestinal microbiota homeostasis by modulating its diversity, or treating critical illness by altering the metabolites of intestinal microbiota. There is growing evidence that fecal microbiota transplantation (FMT), selective digestive decontamination (SDD), and microbiota-derived therapies are all effective treatments for critical illness. However, different treatments are appropriate for different conditions, and more evidence is needed to support the selection of optimal gut microbiota-related treatments for different diseases. This narrative review summarizes the curative effects and limitations of microbiome-based therapeutics in different critically ill adult patients, aiming to provide possible directions for gut microbiome-based therapeutics for critically ill patients such as ventilator-associated pneumonia, sepsis, acute respiratory distress syndrome, and COVID-19, etc.

Rationale for Colonic Pre-Habilitation Prior to Restoration of Gastrointestinal Continuity

The emergence of the gut microbiome as a complex ecosystem that plays a key role in human heath and disease has touched virtually every aspect of medical and surgical care. With the advent of next-generation technology to interrogate the microbiome at the level of its membership, community structure and production of metabolites, applying measures by which the gut microbiome can be manipulated to the advantage of both the patient and provider is now possible. Among the many proposed methods, the most practical and promising is dietary pre-habilitation of the gut microbiome prior to high-risk anastomotic surgery. In this review, we will outline the scientific rationale and molecular underpinning that support dietary pre-habilitation as a practical and deliverable method to prevent complications after high-risk anastomotic surgery.

Is Previous Postoperative Infection an Independent Risk Factor for Postoperative Infection after Second Unrelated Abdominal Operation?

BACKGROUND

Infections after abdominal surgery remain a significant problem. Although preoperative antibiotic prophylaxis is a primary strategy used to reduce postoperative infections, it is typically prescribed based on standardized protocols, without attention to previous infection or antibiotic history. Patients with a previous infection after surgery may be at higher risk for infectious complications after subsequent operations owing to antibiotic resistance. We hypothesized that a previous postoperative infection is a significant risk factor for the development of infection after a second unrelated surgery.

STUDY DESIGN

We performed a retrospective study of patients who had undergone 2 unrelated abdominal operations at a tertiary care center from 2012 to 2018. Clinical variables and microbiological culture results were abstracted. Univariate and multivariable regression models were constructed.

RESULTS

Of 758 patients, 15.0% (n = 114) developed an infection after the first operation. After the second operation, 22.8% (n = 26) of those with a previous infection developed another infection, whereas the incidence of an infection after the second operation was only 9.5% (n = 61) in patients who did not develop an infection after the first operation. Multivariable analysis demonstrated that previous infection (odds ratio 2.49, 95% CI 1.46 to 4.25) was associated with future infection risk. Microbiological analysis found that infections after the second surgery were significantly more likely to be antibiotic resistant than infections after the first surgery (82.3% vs 64.1%; p = 0.036). Strikingly, 49% of infections after the second surgery were resistant to the antibiotic prophylaxis given at the time of incision.

CONCLUSIONS

Previous postoperative infection is an independent risk factor for a subsequent postoperative infection and is associated with resistance to standard prophylaxis. Individualization of antibiotic prophylaxis in patients with a previous postoperative infection is warranted.

Prior Antibiotic Exposure Is Associated With Reoperation After Elective Non-colorectal Surgery

BACKGROUND

Recent antibiotic exposure has previously been associated with poor outcomes following elective surgery. The purpose of this study is to evaluate the impact of prior recent antibiotic exposure in a multicenter cohort of Veterans Affairs patients undergoing elective non-colorectal surgery.

METHODS

This is a retrospective cohort study of the Veterans Affairs Surgical Quality Improvement Program, including elective, non-cardiovascular, non-colorectal surgery from 2013 to 2017. Outpatient antibiotic exposure within 90 days prior to surgery was identified from the Veterans Affairs outpatient pharmacy database and matched with each case. Primary outcomes included serious complication, any complication, any infection, or surgical site infection. Secondary outcomes included 30-day mortality, length of stay, and Clostridioides difficile infection.

RESULTS

Of 21,112 eligible patients, 2885 (13.7%) were exposed to antibiotics within 90 days prior to surgery with a duration of 7 (IQR: 5-10) days and prescribed 42 (IQR: 21-64) days prior to surgical intervention. Compared to non-exposed patients, exposed patients had higher unadjusted complication rates, increased length of stay, and rates of return to the operating. Exposure was independently associated with return to the operating room (OR: 1.39; 99% CI: 1.05-1.84).

CONCLUSIONS

Among Veterans, recent antibiotic exposure within 90 days of elective surgery was associated with a 39% increase in the odds of return to the operating room. Further work is needed to evaluate the effects of antibiotic exposure and dysbiosis on surgical outcomes.

Incidence of Preoperative Antibiotic Use and Its Association with Postoperative Infectious Complications after Radical Cystectomy

OBJECTIVE

To determine exposure rates to antibiotics prior to radical cystectomy and determine if there is correlation with post-operative infections.

METHODS AND MATERIALS

2248 patients were identified in the 2016 SEER-Medicare linkage who underwent radical cystectomy between 2008 and 2014 with complete prescription information. An outpatient prescription for an antibiotic within 30 days prior to cystectomy was considered exposure. Antibiotic class and combinations were recorded. Postoperative infectious diagnoses and readmissions were tabulated within 30 days of cystectomy.

RESULTS

Fifty one percent of patients (n = 1149) were prescribed an outpatient antibiotic prior to cystectomy. Patients receiving antibiotics were more likely to be female (31% vs 25%, P < .01) and had been diagnosed with an infection (17% vs 11%, P < .01). Antibiotic bowel prophylaxis was prescribed to 42% of patients receiving antibiotics. Postoperatively, the exposure group had higher rates of any infection, (56% vs 51% P < .01) and UTI (36% vs 31% P < .01). All-cause readmission within 30 days was higher in the exposure cohort (26% vs 22%, P = .02) Multivariable logistic regression showed outpatient preoperative antibiotics were an independent risk factor for any infection (HR 1.19, P < .05) and readmission (hazards ratio 1.24, P = .03) in the 30 days after radical cystectomy.

CONCLUSION

Outpatient antibiotic use prior to radical cystectomy is common and may be associated with increased risk of postoperative infection and readmission. Antibiotic use prior to radical cystectomy should be examined as a modifiable factor to decrease post-operative morbidity.

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.

The use of fecal microbiota transplant in sepsis

Sepsis is defined as a dysregulated inflammatory response, which ultimately results from a perturbed interaction of both an altered immune system and the biomass and virulence of involved pathogens.  This response has been tied to the intestinal microbiota, as the microbiota and its associated metabolites play an essential role in regulating the host immune response to infection.  In turn, critical illness as well as necessary health care treatments result in a collapse of the intestinal microbiota diversity and a subsequent loss of health-promoting short chain fatty acids, such as butyrate, leading to the development of a maladaptive pathobiome.  These perturbations of the microbiota contribute to the dysregulated immune response and organ failure associated with sepsis.  Several case series have reported the ability of fecal microbiota transplant (FMT) to restore the host immune response and aid in recovery of septic patients.  Additionally, animal studies have revealed the mechanism of FMT rescue in sepsis is likely related to the ability of FMT to restore butyrate producing bacteria and alter the innate immune response aiding in pathogen clearance.  However, several studies have reported lethal complications associated with FMT, including bacteremia.  Therefore, FMT in the treatment of sepsis is and should remain investigational until a more detailed mechanism of how FMT restores the host immune response in sepsis is determined, allowing for the development of more fine-tuned microbiota therapies.