Are enterococci playing a role in postoperative peritonitis in critically ill patients? Eur J Clin Microbiol Infect Dis. 2012;31:1479-1485. [PMID: 22076551 DOI: 10.1007/s10096-011-1467-8]

Epidemiology of vancomycin-resistant enterococci in the United Arab Emirates: a retrospective analysis of 12 years of national AMR surveillance data

INTRODUCTION

Enterococci are usually low pathogenic, but can cause invasive disease under certain circumstances, including urinary tract infections, bacteremia, endocarditis, and meningitis, and are associated with peritonitis and intra-abdominal abscesses. Increasing resistance of enterococci to glycopeptides and fluoroquinolones, and high-level resistance to aminoglycosides is a concern. National antimicrobial resistance (AMR) surveillance data for enterococci from the Middle East and North Africa (MENA) and the Gulf region is scarce.

METHODS

A retrospective 12-year analysis of N = 37,909 non-duplicate diagnostic Enterococcus spp. isolates from the United Arab Emirates (UAE) was conducted. Data was generated by routine patient care during 2010-2021, collected by trained personnel and reported by participating surveillance sites to the UAE National AMR Surveillance program. Data analysis was conducted with WHONET.

RESULTS

Enterococcus faecalis was the most commonly reported species (81.5%), followed by Enterococcus faecium (8.5%), and other enterococci species (4.8%). Phenotypically vancomycin-resistant enterococci (VRE) were found in 1.8% of Enterococcus spp. isolates. Prevalence of VRE (%VRE) was highest for E. faecium (8.1%), followed by E. faecalis (0.9%). A significant level of resistance to glycopeptides (%VRE) for these two species has been observed in the majority of observed years [E. faecalis (0-2.2%), 2010: 0%, 2021: 0.6%] and E. faecium (0-14.2%, 2010: 0%, 2021: 5.8%). Resistance to fluoroquinolones was between 17 and 29% (E. faecalis) and was higher for E. faecium (between 42 and 83%). VRE were associated with higher patient mortality (RR: 2.97), admission to intensive care units (RR: 2.25), and increased length of stay (six excess inpatient days per VRE case), as compared to vancomycin-susceptible Enterococcus spp.

DISCUSSION

Published data on Enterococcus infections, in particular VRE-infections, in the UAE and MENA region is scarce. Our data demonstrates that VRE-enterococci are relatively rare in the UAE, however showing an increasing resistance trend for several clinically important antibiotic classes, causing a concern for the treatment of serious infections caused by enterococci. This study also demonstrates that VRE were associated with higher mortality, increased intensive care unit admission rates, and longer hospitalization, thus poorer clinical outcome and higher associated costs in the UAE. We recommend the expansion of current surveillance techniques (e.g., local VRE screening), stricter infection prevention and control strategies, and better stewardship interventions. Further studies on the molecular epidemiology of enterococci are needed.

Antimicrobial Lessons From a Large Observational Cohort on Intra-abdominal Infections in Intensive Care Units

Severe intra-abdominal infection commonly requires intensive care. Mortality is high and is mainly determined by disease-specific characteristics, i.e. setting of infection onset, anatomical barrier disruption, and severity of disease expression. Recent observations revealed that antimicrobial resistance appears equally common in community-acquired and late-onset hospital-acquired infection. This challenges basic principles in anti-infective therapy guidelines, including the paradigm that pathogens involved in community-acquired infection are covered by standard empiric antimicrobial regimens, and second, the concept of nosocomial acquisition as the main driver for resistance involvement. In this study, we report on resistance profiles of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus faecalis and Enterococcus faecium in distinct European geographic regions based on an observational cohort study on intra-abdominal infections in intensive care unit (ICU) patients. Resistance against aminopenicillins, fluoroquinolones, and third-generation cephalosporins in E. coli, K. pneumoniae and P. aeruginosa is problematic, as is carbapenem-resistance in the latter pathogen. For E. coli and K. pneumoniae, resistance is mainly an issue in Central Europe, Eastern and South-East Europe, and Southern Europe, while resistance in P. aeruginosa is additionally problematic in Western Europe. Vancomycin-resistance in E. faecalis is of lesser concern but requires vigilance in E. faecium in Central and Eastern and South-East Europe. In the subcohort of patients with secondary peritonitis presenting with either sepsis or septic shock, the appropriateness of empiric antimicrobial therapy was not associated with mortality. In contrast, failure of source control was strongly associated with mortality. The relevance of these new insights for future recommendations regarding empiric antimicrobial therapy in intra-abdominal infections is discussed.

Risk Factors for Enterococcal Intra-Abdominal Infections and Outcomes in Intensive Care Unit Patients

Background: To investigate the risk factors for enterococcal intra-abdominal infections (EIAIs) and the association between EIAIs and outcomes in intensive care unit (ICU) patients. Methods: We reviewed retrospectively the records of patients with intra-abdominal infections admitted to the Department of Critical Care Medicine at Nanfang Hospital, Southern Medical University, China, from January 2011 to December 2018. Patients with intra-abdominal infections were divided into enterococcal and non-enterococcal groups based on whether enterococci were isolated from intra-abdominal specimens. Results: A total of 431 patients with intra-abdominal infections were included, of whom 119 were infected with enterococci and 312 were infected with non-enterococci. Enterococci were isolated in 27.6% of patients, accounting for 24.5% (129/527) of all clinical bacterial isolates. Post-operative abdominal infection (adjusted odds ratio [OR], 2.361; p = 0.004), intestinal infection (adjusted OR, 2.703; p < 0.001), Mannheim Peritonitis Index score (MPI; adjusted OR, 1.052; p = 0.015), and use of antibiotic agents within the previous 90 days (adjusted OR, 1.880; p = 0.025) were associated with an increased risk of EIAIs. Compared with patients without enterococcal infection, ICU patients with enterococcal infection had a higher risk of failure of initial clinical therapy (49.6% vs. 24.2%; p < 0.001) and longer hospital stays (33 days [19, 48] vs. 18 days [12, 29]; p < 0.001). Enterococcal infection was associated with increased 28-day mortality, in-hospital mortality, and ICU mortality. However, no difference was found in length of ICU stay between the two groups. Additionally, there was no difference in ICU mortality, hospital mortality, or 28-day mortality in patients infected with enterococcus who did or did not receive empirical anti-enterococcal therapy. Conclusion: Post-operative abdominal infection, intestinal infection, MPI score, and use of antibiotic agents within the previous 90 days were independent risk factors for enterococcal infection. Enterococcal infection was associated with reduced short-term survival in ICU patients.

Diagnosis and Management of Intraabdominal Infection: Guidelines by the Chinese Society of Surgical Infection and Intensive Care and the Chinese College of Gastrointestinal Fistula Surgeons

The Chinese guidelines for IAI presented here were developed by a panel that included experts from the fields of surgery, critical care, microbiology, infection control, pharmacology, and evidence-based medicine. All questions were structured in population, intervention, comparison, and outcomes format, and evidence profiles were generated. Recommendations were generated following the principles of the Grading of Recommendations Assessment, Development, and Evaluation system or Best Practice Statement (BPS), when applicable. The final guidelines include 45 graded recommendations and 17 BPSs, including the classification of disease severity, diagnosis, source control, antimicrobial therapy, microbiologic evaluation, nutritional therapy, other supportive therapies, diagnosis and management of specific IAIs, and recognition and management of source control failure. Recommendations on fluid resuscitation and organ support therapy could not be formulated and thus were not included. Accordingly, additional high-quality clinical studies should be performed in the future to address the clinicians' concerns.

Treatment with Ceftriaxone in Complicated Diverticulitis Increases the Incidence of Intra-Abdominal Enterococcus faecium Detection

Background: Complicated diverticulitis of the sigmoid colon typically is treated by resection after initial antibiotic treatment. Third-generation cephalosporins are the drugs of choice but are not effective against enterococci and can induce colonic colonization by Enterococcus faecium within hours. Infections caused by enterococci, especially E. faecium, are difficult to treat but should be considered in the strategic treatment planning of hospital-acquired peritonitis (e.g., anastomotic leakage), especially in immunocompromised patients. Methods: To determine whether the duration of pre-operative ceftriaxone treatment in complicated diverticulitis increases the incidence of intra-abdominal E. faecium detection, we analyzed all patients operated on for diverticulitis of the sigmoid colon in our department between 2008 and 2016. Results: Analyzing 516 resections performed for complicated diverticulitis, we found that E. faecium generally was detected intra-abdominally more often in the group that underwent longer pre-operative ceftriaxone treatment (≥ 4 days). During primary resection, E. faecium was detected in 2.7%, 11.1%, and 37.0% cases in the group undergoing immediate operation, 1-3 days of antibiotic treatment, and ≥4 days of antibiotic treatment, respectively. Enterococcus faecium was detected in 0, 25.0%, and 70.6% of surgical revisions and 28.6%, 14.3%, and 56.0%, respectively, of incisional surgical site infections with identified pathogens. A multivariable analysis discovered anastomotic leakage and antibiotic treatment lasting ≥4 days to be independent risk factors for intra-abdominal isolation of E. faecium. Conclusion: A ceftriaxone treatment ≥4 days led to a higher incidence of intra-abdominal E. faecium. Our data further suggested that empiric coverage of E. faecium in the treatment of hospital-acquired peritonitis could be beneficial after a long duration of ceftriaxone treatment.

Systematic Review and Meta-Analysis of the Efficacy of Appropriate Empiric Anti-Enterococcal Therapy for Intra-Abdominal Infection

Background: Delayed treatment of seriously infected patients results in increased mortality. However, antimicrobial therapy for the initial 24 to 48 hours is mostly empirically provided, without evidence regarding the causative pathogen. Whether empiric anti-enterococcal therapy should be administered to treat intra-abdominal infection (IAI) before obtaining culture results remains unknown. We performed a meta-analysis to explore the effects of empiric enterococci covered antibiotic therapy in IAI and the risk factors for enterococcal infection in IAI. Methods: We searched multiple databases systematically and included 23 randomized controlled trials (RCTs) and 13 observational studies. The quality of included studies was assessed, and the reporting bias was evaluated. Meta-analysis was performed using random effects or fixed effects models according to the heterogeneity. The risk ratio (RR), odds ratio (OR), and 95% confidence interval (CI) were calculated. Results: Enterococci-covered antibiotic regimens provided no improvement in treatment success compared with control regimens (RR, 0.99; 95% CI, 0.97-1.00; p = 0.15), with similar mortality and adverse effects in both arms. Basic characteristic analysis revealed that most of the enrolled patients with IAI in RCTs were young, lower risk community-acquired intra-abdominal infection (CA-IAI) patients with a relatively low APACHE II score. Interestingly, risk factor screening revealed that malignancy, corticosteroid use, operation, any antibiotic treatment, admission to intensive care unit (ICU), and indwelling urinary catheter could predispose the patients with IAI to a substantially higher risk of enterococcal infection. "Hospital acquired" itself was a risk factor (OR, 2.81; 95% CI, 2.34-3.39; p < 0.001). Conclusion: It is unnecessary to use additional agents empirically to specifically provide anti-enterococcal coverage for the management of CA-IAI in lower risk patients without evidence of causative pathogen, and risk factors can increase the risk of enterococcal infection. Thus, there is a rationale for providing empiric anti-enterococcal coverage for severely ill patients with CA-IAI with high risk factors and patients with hospital-acquired intra-abdominal infection (HA-IAI).

Perioperative prophylaxis with single-dose cefazolin for liver transplantation: a retrospective study

BACKGROUND

Early infections are common during the first month after liver transplantation (LT), whereas no consensus exists on the optimal prophylactic antimicrobial therapy. We aimed to evaluate the effectiveness of cefazolin perioperative prophylaxis in LT.

PATIENTS AND METHODS

We documented our experience with single-dose cefazolin as prophylaxis for LT. Infections occurring within 30 days following LT during 2006-2015 were documented retrospectively. Univariate and multivariate analyses of risk factors for infection were carried out.

RESULTS

Among 113 LT recipients receiving cefazolin as prophylaxis, infections occurred in 50 (44%) patients, including surgical site infections (n=24, 21%) and bacteremia (n=14, 12%). Bacteria resistant to cefazolin were documented in 59/72 (82%) isolates. Enterococcal infections were documented in 6% (7/113). Almost half of the infections (44%) occurred in the first week following LT and the vast majority within 2 weeks. The 30-day mortality rate (7%, 8/113) was significantly higher among infected patients (7/50, 14% vs. 1/63, 1.6%, P=0.011). Model for End-stage Liver Disease score, age, and requirement for at least 5 U of packed red cells during transplantation were predictive for postoperative infections.

CONCLUSION

In our center, cefazolin was insufficient as perioperative prophylaxis in LT. We suggest that all LT recipients should receive antibiotic prophylaxis targeting microorganisms on the basis of local bacterial ecology and patterns of resistance irrespective of preoperative or intraoperative risk assessment.

[Enterococci and surgical site infections : Causal agent or harmless commensals?]

BACKGROUND

The role of enterococci in the context of peritonitis and surgical site infections (SSI) has not yet been definitively clarified but enterococci are being detected more frequently. Numerous resistances reduce the available antibiotic options.

OBJECTIVE

This article gives an overview of the pathogenic importance of enterococci and of current recommendations for therapy and prophylaxis. On the basis of our own data we discuss the relevance of enterococci for SSI.

MATERIAL AND METHODS

All colorectal resections carried out between January 2008 and September 2016 were retrospectively documented. Revision surgery, SSI and intra-abdominally or subcutaneously detected pathogens were recorded.

RESULTS

A total of 2713 interventions were evaluated with 28.3% having primary peritonitis. In 587 patients (21.6%) SSI followed, and pathogen determination was possible in 431 cases (73.4%). Enterococci were frequently found in re-operations (58.4%) and SSI (46.1%), with E. faecalis and E. faecium in approximately equal proportions. If intra-abdominal enterococci were detectable in patients with primary peritonitis, it was more common to develop SSI and enterococci were more frequently detected subcutaneously. Enterococci in SSI were found to be significantly more frequent in left hemicolectomies as well as in pre-existing renal insufficiency.

CONCLUSION

It can be inferred that enterococci are not adequately covered by commonly used perioperative antibiotic therapy or preoperative prophylaxis, which increases the risk for SSI by enterococci. This could be favored by selection of these pathogens due to the use of antibiotics without enterococcal efficacy (e. g. cephalosporins). The consideration in the choice of perioperative antibiotic prophylaxis by the additional administration of ampicillin or vancomycin could be advantageous.

The Surgical Infection Society Revised Guidelines on the Management of Intra-Abdominal Infection

BACKGROUND

Previous evidence-based guidelines on the management of intra-abdominal infection (IAI) were published by the Surgical Infection Society (SIS) in 1992, 2002, and 2010. At the time the most recent guideline was released, the plan was to update the guideline every five years to ensure the timeliness and appropriateness of the recommendations.

METHODS

Based on the previous guidelines, the task force outlined a number of topics related to the treatment of patients with IAI and then developed key questions on these various topics. All questions were approached using general and specific literature searches, focusing on articles and other information published since 2008. These publications and additional materials published before 2008 were reviewed by the task force as a whole or by individual subgroups as to relevance to individual questions. Recommendations were developed by a process of iterative consensus, with all task force members voting to accept or reject each recommendation. Grading was based on the GRADE (Grades of Recommendation Assessment, Development, and Evaluation) system; the quality of the evidence was graded as high, moderate, or weak, and the strength of the recommendation was graded as strong or weak. Review of the document was performed by members of the SIS who were not on the task force. After responses were made to all critiques, the document was approved as an official guideline of the SIS by the Executive Council.

RESULTS

This guideline summarizes the current recommendations developed by the task force on the treatment of patients who have IAI. Evidence-based recommendations have been made regarding risk assessment in individual patients; source control; the timing, selection, and duration of antimicrobial therapy; and suggested approaches to patients who fail initial therapy. Additional recommendations related to the treatment of pediatric patients with IAI have been included.

SUMMARY

The current recommendations of the SIS regarding the treatment of patients with IAI are provided in this guideline.

Risk factors for mortality in postoperative peritonitis in critically ill patients

AIM

To identify the risk factors for mortality in intensive care patients with postoperative peritonitis (POP).

METHODS

This was a retrospective analysis using a prospective database that includes all patients hospitalized in a surgical intensive care unit for POP from September 2006 to August 2011. The data collected included demographics, comorbidities, postoperative severity parameters, bacteriological findings, adequacy of antimicrobial therapy and surgical treatments. Adequate source control was defined based on a midline laparotomy, infection source control and intraoperative peritoneal lavage. The number of reoperations needed was also recorded.

RESULTS

A total of 201 patients were included. The overall mortality rate was 31%. Three independent risk factors for mortality were identified: The Simplified Acute Physiological II Score (OR = 1.03; 95%CI: 1.02-1.05, P < 0.001), postoperative medical complications (OR = 6.02; 95%CI: 1.95-18.55, P < 0.001) and the number of reoperations (OR = 2.45; 95%CI: 1.16-5.17, P = 0.015). Surgery was considered as optimal in 69% of the cases, but without any significant effect on mortality.

CONCLUSION

The results from the large cohort in this study emphasize the role of the initial postoperative severity parameters in the prognosis of POP. No predefined criteria for optimal surgery were significantly associated with increased mortality, although the number of reoperations appeared as an independent risk factor of mortality.

Guidelines for management of intra-abdominal infections

Intra-abdominal infections are one of the most common gastrointestinal emergencies and a leading cause of septic shock. A consensus conference on the management of community-acquired peritonitis was published in 2000. A new consensus as well as new guidelines for less common situations such as peritonitis in paediatrics and healthcare-associated infections had become necessary. The objectives of these Clinical Practice Guidelines (CPGs) were therefore to define the medical and surgical management of community-acquired intra-abdominal infections, define the specificities of intra-abdominal infections in children and describe the management of healthcare-associated infections. The literature review was divided into six main themes: diagnostic approach, infection source control, microbiological data, paediatric specificities, medical treatment of peritonitis, and management of complications. The GRADE(®) methodology was applied to determine the level of evidence and the strength of recommendations. After summarising the work of the experts and application of the GRADE(®) method, 62 recommendations were formally defined by the organisation committee. Recommendations were then submitted to and amended by a review committee. After 2 rounds of Delphi scoring and various amendments, a strong agreement was obtained for 44 (100%) recommendations. The CPGs for peritonitis are therefore based on a consensus between the various disciplines involved in the management of these patients concerning a number of themes such as: diagnostic strategy and the place of imaging; time to management; the place of microbiological specimens; targets of empirical anti-infective therapy; duration of anti-infective therapy. The CPGs also specified the value and the place of certain practices such as: the place of laparoscopy; the indications for image-guided percutaneous drainage; indications for the treatment of enterococci and fungi. The CPGs also confirmed the futility of certain practices such as: the use of diagnostic biomarkers; systematic relaparotomies; prolonged anti-infective therapy, especially in children.

Essentials for selecting antimicrobial therapy for intra-abdominal infections

Intra-abdominal infection (IAI) is a complex disease entity in which different aspects must be balanced in order to select the proper antimicrobial regimen and determine duration of therapy. A current classification indicates different faces of peritonitis. Primary peritonitis implies an intact gastrointestinal tract without overt barrier disruption. Secondary peritonitis refers to localized or diffuse peritoneal inflammation and abscess formation due to disruption of the anatomical barrier. Tertiary peritonitis includes cases that cannot be solved by a single or even sequential surgical intervention, often in combination with sequential courses of antimicrobial therapy. The most frequently used classification distinguishes ‘uncomplicated’ and ‘complicated’ IAI. In uncomplicated IAI, the infectious process is contained within a single organ, without anatomical disruption. In complicated IAI, disease is extended, with either localized or generalized peritonitis. However, there exists more than a single dimension of complexity in IAI, including severity of disease expression through systemic inflammation. As the currently used classifications of IAI often incite confusion by mixing elements of anatomical barrier disruption, severity of disease expression and (the likelihood of) resistance involvement, we propose an alternative for the current widely accepted classification. We suggest abandoning the terms ‘uncomplicated’ and ‘complicated’ IAI, as they merely confuse the issue. Furthermore, the term ‘tertiary peritonitis’ should likewise be discarded, as this simply refers to treatment failure of secondary peritonitis resulting in a state of persistent infection and/or inflammation. Hence, anatomical disruption and disease severity should be separated into different phenotypes for the same disease in combination with either presence or absence of risk factors for involvement of pathogens that are not routinely covered in first-line antimicrobial regimens (Pseudomonas aeruginosa, enterococci, Candida species and resistant pathogens). Generally, these risk factors can be brought back to recent exposure to antimicrobial agents and substantial length of stay in healthcare settings (5–7 days). As such, we developed a grid based on the different components of the classification: (i) anatomical disruption; (ii) severity of disease expression; and (iii) either community-acquired/early-onset healthcare-associated origin or healthcare-associated origin and/or recent antimicrobial exposure. The grid allows physicians to define the index case of IAI in a more unequivocal way and to select the most convenient empirical antimicrobial regimens. The grid advises on the necessity of covering nosocomial Gram-negative bacteria (including P. aeruginosa), enterococci and yeasts. The basis of antimicrobial therapy for IAI is that both Gram-negative and anaerobic bacteria should always be covered.

In recent years, some newer agents such as doripenem, moxifloxacin and tigecycline have been added to the antimicrobial armamentarium for IAI. For patients in whom the source can be adequately controlled, antimicrobial therapy should be restricted to a short course (e.g. 3–7 days in peritonitis).

Emergence of spontaneous bacterial peritonitis due to enterococci - risk factors and outcome in a 12-year retrospective study

BACKGROUND

Third-generation cephalosporins (TGC) constitute the empirical first-line therapy for spontaneous bacterial peritonitis (SBP). Hospitalisation, invasive procedures and use of antibiotics may challenge this concept due to an increase in enterococci and other TGC-resistant microorganisms.

AIM

To determine prevalence, risk factors and outcome of ascitic fluid infections caused by enterococci.

METHODS

All independent episodes of culture-positive ascitic fluid between 2000 and 2011 in a German tertiary centre were analysed retrospectively.

RESULTS

Out of 244 positive ascitic fluid cultures, 90 episodes of monomicrobial SBP and 25 episodes of monomicrobial bacterascites (BA) in patients with decompensated cirrhosis were identified. Enterococcus spp. were isolated in 32 (28%) episodes. We noticed a profound increase in the frequency of enterococcal infection over the study period from 11% to 35% (P = 0.007). Univariate risk factors for enterococcal SBP/BA included nosocomial infection (OR = 4.56; 95% CI 1.90-10.97), previous use of antibiotics (OR = 5.63; 95% CI 1.81-17.49) and recent gastrointestinal endoscopy (OR = 3.17; 95% CI 1.33-7.54). Nosocomial infection (OR = 3.29; P = 0.011) and recent antibiotic therapy (OR = 3.88; P = 0.025) remained independent risk factors for enterococcal infection in multivariate logistic regression and these factors contributed also to the model when only SBP cases were considered. In subjects with monomicrobial SBP who were treated with TGC or ciprofloxacin, the probability of 90-day survival was 12% in enterococcal infection compared to 50% in non-enterococcal SBP (P = 0.022 in log-rank test).

CONCLUSION

Because of the increasing prevalence of enterococcal spontaneous bacterial peritonitis and its poor prognosis when treated inappropriately, clinicians should consider empirical therapy with anti-enterococcal antibiotics for patients with risk factors.