A Comprehensive review of abdominal infections

A fungal metabolic regulator underlies infectious synergism during Candida albicans-Staphylococcus aureus intra-abdominal co-infection

Candida albicans and Staphylococcus aureus are two commonly associated pathogens that cause nosocomial infections with high morbidity and mortality. Our prior and current work using a murine model of polymicrobial intra-abdominal infection (IAI) demonstrates that synergistic lethality is driven by Candida-induced upregulation of functional S. aureus α-toxin leading to polymicrobial sepsis and organ damage. In order to determine the candidal effector(s) mediating enhanced virulence, an unbiased screen of C. albicans transcription factor mutants was undertaken revealing that zcf13Δ/Δ fails to drive augmented α-toxin or lethal synergism during co-infection. A combination of transcriptional and phenotypic profiling approaches shows that ZCF13 regulates genes involved in pentose metabolism, including RBK1 and HGT7 that contribute to fungal ribose catabolism and uptake, respectively. Subsequent experiments reveal that ribose inhibits the staphylococcal agr quorum sensing system and concomitantly represses toxicity. Unlike wild-type C. albicans, zcf13Δ/Δ did not effectively utilize ribose during co-culture or co-infection leading to exogenous ribose accumulation and agr repression. Forced expression of RBK1 and HGT7 in the zcf13Δ/Δ mutant fully restores pathogenicity during co-infection. Collectively, our results detail the interwoven complexities of cross-kingdom interactions and highlight how intermicrobial metabolism impacts polymicrobial disease pathogenesis with devastating consequences for the host.

Urea to Albumin Ratio Is an Excellent Predictor of Death in Patients With Complicated Intra-Abdominal Infections

Background: The urea to albumin ratio (UAR) has shown a prognostic value in various clinical settings, however, no study has yet investigated its ability to predict outcome in complicated intra-abdominal infections (cIAIs). Therefore, our aim was to evaluate the association between UAR and mortality in such patients. Patients and Methods: A single-center prospective study including 62 patients with cIAIs was performed at a University Hospital Stara Zagora for the period November 2018 to August 2021. Various routine laboratory and clinical parameters were recorded before surgery and on post-operative day 3. We used serum levels of urea and albumin to calculate the UAR. Results: The observed in-hospital mortality was 14.5%. Non-survivors had higher pre- and post-operative median of UAR than survivors (88.39 vs. 30.99, p < 0.0001 and 106.18 vs. 26.58, p < 0.0001, respectively). Lethal outcome was predicted successfully both by UAR before surgery (area under receiver operating characteristics [AUROC] curves = 0.889; p < 0.0001) at a threshold of 61.42 and on third post-operative day (AUROC = 0.943; p < 0.0001) at a threshold = 55.89. Conclusions: Peri-operative UAR showed an excellent ability for prognostication of fatal outcome in patients with cIAIs.

A fungal metabolic regulator underlies infectious synergism during Candida albicans - Staphylococcus aureus intra-abdominal co-infection

Candida albicans and Staphylococcus aureus are two commonly associated pathogens that cause nosocomial infections with high morbidity and mortality. Our prior and current work using a murine model of polymicrobial intra-abdominal infection (IAI) uncovered synergistic lethality that was driven by Candida -induced upregulation of functional S. aureus ⍺-toxin leading to polymicrobial sepsis and organ damage. In order to determine the candidal effector(s) mediating enhanced virulence, an unbiased screen of C. albicans transcription factor mutants was undertaken and revealed that zcf13 Δ/Δ failed to drive augmented ⍺-toxin or lethal synergism during co-infection. Using a combination of transcriptional and phenotypic profiling approaches, ZCF13 was shown to regulate genes involved in pentose metabolism, including RBK1 and HGT7 that contribute to fungal ribose catabolism and uptake, respectively. Subsequent experiments revealed that ribose inhibited the staphylococcal agr quorum sensing system and concomitantly repressed toxicity. Unlike wild-type C. albicans , zcf13 Δ/Δ was unable to effectively utilize ribose during co-culture or co-infection leading to exogenous ribose accumulation and agr repression. Forced expression of RBK1 and HGT7 in the zcf13 Δ/Δ mutant fully restored pathogenicity during co-infection. Collectively, our results detail the interwoven complexities of cross-kingdom interactions and highlight how intermicrobial metabolism impacts polymicrobial disease pathogenesis with devastating consequences for the host.

Effects of Early Initiation of Polymyxin B Hemoperfusion Therapy in Patients with Cancer with Refractory Septic Shock

Background: We aimed to analyze the correlation between in-hospital mortality and hemodynamic changes, using polymyxin B-immobilized fiber column direct hemoperfusion (PMX-DHP) initiation time in patients with cancer with refractory septic shock. Methods: Forty-six patients with cancer who received PMX-DHP for refractory septic shock were retrospectively analyzed and classified into early (≤3 h between refractory septic shock and PMX-DHP; n = 17) and late (>3 h; n = 29) initiation groups. The vasopressor inotropic score (VIS), sequential organ failure assessment (SOFA) score, and lactate clearance before and 24 h post-PMX-DHP were compared. Results: Overall, 52.17% died from multiple organ dysfunction, with a lower mortality rate in the early initiation group. The VIS and SOFA score decreased in both groups, but the magnitude of decrease was not significant. Lactate clearance improved in both groups, with greater improvement in the early initiation group. Univariable analysis identified associations of in-hospital mortality with early initiation, ΔC-reactive protein, lactate clearance, ΔSOFA score, and ΔVIS. Multivariable analysis demonstrated associations of in-hospital mortality risk with ΔSOFA score and early PMX-DHP initiation. Overall survival was higher in the early initiation group. Early initiation of PMX-DHP in patients with cancer with refractory septic shock reduced in-hospital mortality and improved lactate clearance.

Identification of Risk Factors for Intra-Abdominal Candidiasis

Background: Intra-abdominal candidiasis (IAC) is associated with substantial morbidity and mortality in hospitalized patients. Identifying high-risk populations may facilitate early and selective directed therapy in appropriate patients and avoid unwarranted treatment and any associated adverse effects in those who are low risk. Patients and Methods: This retrospective, case-control study included patients >18 years of age admitted from July 1, 2010 to July 1, 2021 who had a microbiologically confirmed intra-abdominal infection (gastrointestinal culture positive for either a Candida spp. [cases] or bacterial isolate [controls] collected intra-operatively or from a drain placed within 24 hours). Patients receiving peritoneal dialysis treatment or with a peritoneal dialysis catheter in place or treated at an outside hospital were excluded. Multivariable regression was utilized to identify independent risk factors for the development of IAC. Results: Five hundred twenty-three patients were screened, and 250 met inclusion criteria (125 per cohort). Multivariable analysis identified exposure to corticosteroids (odds ratio [OR], 5.79; 95% confidence interval [CI], 2.52-13.32; p < 0.0001), upper gastrointestinal tract surgery (OR, 3.51; 95% CI, 1.25-9.87; p = 0.017), and mechanical ventilation (OR, 3.09; 95% CI 1.5-6.37; p = 0.002) were independently associated with IAC. The area under the receiver operating characteristic (AUROC) and goodness of fit were 0.7813 and p = 0.5024, respectively. Conclusions: Exposure to corticosteroids, upper gastrointestinal tract surgery, and mechanical ventilation are independent risk factors for the development of microbiologically confirmed IAC suggesting these factors may help identify high-risk individuals requiring antifungal therapy.

Effects of prior antiplatelet and/or nonsteroidal anti-inflammatory drug use on mortality in patients undergoing abdominal surgery for abdominal sepsis

BACKGROUND

The effects of prior antiplatelet and/or nonsteroidal anti-inflammatory drug (NSAID) use on mortality in critically ill patients remain unclear. We investigated the relationship between antiplatelet and/or NSAID use and mortality in patients who had undergone surgery for sepsis caused by intra-abdominal infection.

METHODS

We obtained data from adult patients (aged >18 years) admitted to the intensive care unit after abdominal surgery due to intra-abdominal infection. The patients were categorized into those with and without prior antiplatelet and/or NSAID use.

RESULTS

Overall, 241 patients were enrolled, with 76 in the antiplatelet and/or NSAID use group and 165 in the non-use group. The 60-day survival probabilities for the antiplatelet and/or NSAID use and non-use groups were 85.5% and 73.3%, respectively, and this difference was significant (P = .040). In the multivariate analysis of 28-day mortality, higher Acute Physiology and Chronic Health Evaluation II score (P < .001), Simplified Acute Physiology Score III (P < .001), and blood transfusion within 5 days postoperatively (P = .034) were significant mortality risk factors. In the multivariate analysis of 60-day mortality, higher Acute Physiology and Chronic Health Evaluation II score (P = .002), Simplified Acute Physiology Score III (P < .001), and blood transfusion within 5 days postoperatively (P = .006) were also significant mortality risk factors. However, prior drug use (P = .036) was a factor in reducing mortality.

CONCLUSION

Patients with a prior history of antiplatelet and/or NSAID use had a higher 60-day survival than those who did not use these drugs. Prior antiplatelet and/or NSAID use was significantly associated with a reduction in 60-day mortality.

Antimicrobial Susceptibility of E. coli Isolates from Intra-Abdominal Infections in the Asia-Pacific Region: Trends in Ciprofloxacin, Ceftriaxone, Cefepime, and Piperacillin/Tazobactam Susceptibility

Purpose

To investigate the antibiotic susceptibility of Escherichia coli isolates in patients diagnosed with intra-abdominal infections (IAIs) in the Asia-Pacific region.

Patients and Methods

This study was conducted at 50 medical hospitals across 9 countries/regions as part of the Study for Monitoring Antimicrobial Resistance Trends (SMART) surveillance program from 2014 to 2018. Nonduplicate isolates of aerobic and facultative gram-negative bacilli were collected and processed for further antimicrobial susceptibility testing.

Results

A total of 10,709 isolates were collected, with E. coli (n=4737, 44.2%) being the leading pathogen causing IAIs, followed by Klebsiella pneumoniae (n=2429, 22.7%) and Pseudomonas aeruginosa (n=931, 8.7%). Community-associated (CA) E. coli isolates generally exhibited higher susceptibility rates for most antibiotics than hospital-associated (HA) isolates. In countries/regions other than Hong Kong, South Korea, and Singapore, HA isolates displayed lower susceptibility rates for multiple classes (≥4) of antibiotics. Among the commonly used antibiotics in IAIs, the overall susceptibility rate for ciprofloxacin was low, with an average of 41.3%. Ceftriaxone susceptibility rates in all selected countries were below 80% starting in 2018, ranging from 23.3% to 75.8%. The cefepime susceptibility rates varied across regions, with consistently reduced susceptibility ranging from 45.5% to 57.8% in India, Thailand, and Vietnam. Piperacillin/tazobactam demonstrated effectiveness against E. coli isolates in almost all countries except India, with a downward trend observed in the Philippines and Taiwan. Carbapenems remained effective against more than 90% of E. coli isolates, except in India.

Conclusion

Prudent use of fluoroquinolones and ceftriaxone is advised when treating both CA and HA IAIs in the Asia-Pacific region. The low susceptibility rate of cefepime in India, Thailand, and Vietnam needs careful consideration in its administration. Moreover, the increase in nonsusceptibility to piperacillin/tazobactam in the Philippines and Taiwan poses a potential risk that should be closely monitored.

Analysis of Bacterial Pathogens Causing Complicating HAP in Patients with Secondary Peritonitis

Background: Diffuse peritonitis is an acute abdominal condition characterized by high mortality. The main treatment modality is surgery, requiring a subsequent prolonged hospital stay. These patients are, among other things, at risk of developing hospital-acquired pneumonia (HAP), which considerably worsens their treatment outcomes. This study aimed to extend the existing knowledge by providing more detailed microbiological characteristics of complicating HAP in patients with secondary peritonitis, including the identification of isolated bacterial pathogens and their potential sources. Methods: The 2015–2019 retrospective study comprised all patients with an intraoperatively confirmed diagnosis of secondary diffuse peritonitis who were classified in accordance with the quick Sepsis Related Organ Failure Assessment scoring system. Results: HAP developed in 15% of patients. The 90-day mortality rates were 53% and 24% in patients with and without HAP; respectively. The most frequent pathogens responsible for HAP were Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae complex and Enterococcus faecalis. Multidrug resistance to antibiotics was found in 38% of bacterial pathogens. Clonal spread of these bacterial pathogens among patients was not detected. Rather, the endogenous characteristic of HAP was confirmed. Conclusions: The initial antibiotic therapy of complicating HAP in patients with secondary peritonitis must be effective mainly against enterobacteria, including strains with the production of ESBL and AmpC beta-lactamases, Pseudomonas aeruginosa and Enterococcus faecalis. The study further highlighted the importance of monitoring the respiratory tract bacterial microflora in patients with secondary peritonitis. The results should be used for initial antibiotic treatment of complicating HAP instances.

Association of the origin of contamination and species of microorganisms with short-term survival in dogs with septic peritonitis

OBJECTIVE

To assess the association between anatomical location of contamination and mortality in dogs with gastrointestinal and biliary origin of septic peritonitis.

METHODS

Medical records at two private referral hospitals between 2003 and 2020 were retrospectively reviewed. Cases were included if the origin of contamination was confirmed intraoperatively within the gastrointestinal or biliary tract. Cases were excluded if the dog died or was euthanized intraoperatively or where the data regarding the origin of contamination were not available. The association of anatomical origin with survival was assessed specifying the locations as stomach, small intestine, large intestine and biliary tract. The gastrointestinal tract origin was further subdivided into pylorus, nonpylorus, duodenum, jejunum, ileum, caecum and colon.

RESULTS

The overall survival rate was 75.9% (n = 44/58). There were no significant differences in survival among different anatomical origins of contaminations before or after subdivision (P = 0.349 and 0.832, respectively). Also, there was no association between isolated microorganism species in microbiological culture and the anatomical origin (P = 0.951) and the microorganism species was not associated with survival (P = 0.674).

CONCLUSIONS

There was no association between anatomical location of leakage, microorganism species and survival although further studies are warranted to analyse the relationships between anatomical leakage site and microorganism species as well as microorganism species and mortality.

Transferrin decorated PLGA encumbered moxifloxacin nanoparticles and in vitro cellular studies

PURPOSE

Complicated intra-abdominal infection (cIAI) management involves administering antibiotics that destroy the cell wall and the genesis of bacterial lipopolysaccharide (LPS). During the infectious state, the expression of transferrin receptors upregulates on the intestinal epithelial cells, which are considered the site of infection. In the present research, transferrin decorated poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) encapsulated moxifloxacin (MOX) were developed for possible targeting of the receptors in the colon.

SIGNIFICANCE

This study will explore more about the incorporation of transferrin as effective coating material in targeted drug delivery.

METHODS

Nanoparticles were prepared using nano-emulsification and surface modification with transferrin was done by layer-by-layer methodology and evaluated by powder X-ray diffraction (PXRD), differential scanning calorimeter (DSC), FTIR, SEM, antibacterial activity, and cellular uptake studies.

RESULTS

The formulated NPs exhibit a size of ≈170 nm, PDI ≈ 0.25, zeta potential ≈-4.0 mV, drug loading ≈ 6.8%, and entrapment efficiency of 82%. Transferrin-decorated NPs exhibit tailored release for almost 12 h and in vitro antibacterial activity for 14 h. The cellular uptake studies were done on a RAW264.7 cell line for better determination of transferrin uptake of fabricated NPs.

CONCLUSION

The above study circumvents around the preparation of transferrin decorated PLGA encumbered MOX NPs intended for cIAI-induced sepsis. PLGA NPs provide tailored release of MOX with primary burst and followed by sustained release. These observations confines with antibacterial activity studies. The prepared transferrin-coated NPs were stable and effectively uptaken by RAW264.7 cells. However, future studies include the preclinical investigation of these NPs in sepsis-induced murine models.

Clinical outcomes and prognostic factors of patients with sepsis caused by intra-abdominal infection in the intensive care unit: a post-hoc analysis of a prospective cohort study in Korea

BACKGROUND

Sepsis is the most common cause of death in hospitals, and intra-abdominal infection (IAI) accounts for a large portion of the causes of sepsis. We investigated the clinical outcomes and factors influencing mortality of patients with sepsis due to IAI.

METHODS

This post-hoc analysis of a prospective cohort study included 2126 patients with sepsis who visited 16 tertiary care hospitals in Korea (September 2019-February 2020). The analysis included 219 patients aged > 19 years who were admitted to intensive care units owing to sepsis caused by IAI.

RESULTS

The incidence of septic shock was 47% and was significantly higher in the non-survivor group (58.7% vs 42.3%, p = 0.028). The overall 28-day mortality was 28.8%. In multivariable logistic regression, after adjusting for age, sex, Charlson Comorbidity Index, and lactic acid, only coagulation dysfunction (odds ratio: 2.78 [1.47-5.23], p = 0.001) was independently associated, and after adjusting for each risk factor, only simplified acute physiology score III (SAPS 3) (p < 0.001) and continuous renal replacement therapy (CRRT) (p < 0.001) were independently associated with higher 28-day mortality.

CONCLUSIONS

The SAPS 3 score and acute kidney injury with CRRT were independently associated with increased 28-day mortality. Additional support may be needed in patients with coagulopathy than in those with other organ dysfunctions due to IAI because patients with coagulopathy had worse prognosis.

Korean Guidelines for Use of Antibiotics for Intra-abdominal Infections in Adults

The guidelines are intended to provide practical information for the correct use of antibiotics for intra-abdominal infections in Korea. With the aim of realizing evidence-based treatment, these guidelines for the use of antibiotics were written to help clinicians find answers to key clinical questions that arise in the course of patient care, using the latest research results based on systematic literature review. The guidelines were prepared in consideration of the data on the causative pathogens of intra-abdominal infections in Korea, the antibiotic susceptibility of the causative pathogens, and the antibiotics available in Korea.

Genomics and pathotypes of the many faces of Escherichia coli

Escherichia coli is the most researched microbial organism in the world. Its varied impact on human health, consisting of commensalism, gastrointestinal disease, or extraintestinal pathologies, has generated a separation of the species into at least eleven pathotypes (also known as pathovars). These are broadly split into two groups, intestinal pathogenic E. coli (InPEC) and extraintestinal pathogenic E. coli (ExPEC). However, components of E. coli's infinite open accessory genome are horizontally transferred with substantial frequency, creating pathogenic hybrid strains that defy a clear pathotype designation. Here, we take a birds-eye view of the E. coli species, characterizing it from historical, clinical, and genetic perspectives. We examine the wide spectrum of human disease caused by E. coli, the genome content of the bacterium, and its propensity to acquire, exchange, and maintain antibiotic resistance genes and virulence traits. Our portrayal of the species also discusses elements that have shaped its overall population structure and summarizes the current state of vaccine development targeted at the most frequent E. coli pathovars. In our conclusions, we advocate streamlining efforts for clinical reporting of ExPEC, and emphasize the pathogenic potential that exists throughout the entire species.

Is ß-d-glucan Relevant for the Diagnosis and Follow-Up of Intensive Care Patients with Yeast-Complicated Intra-Abdominal Infection?

The usefulness of (1,3)-ß-d-glucan (BDG) detection for the diagnosis of intra-abdominal candidiasis and treatment monitoring is unknown. A prospective, single-center study of consecutive patients admitted to an ICU with complicated intra-abdominal infection (IAI) over a 2-year period was conducted. BDG was measured in the peritoneal fluid and serum between day 1 (D1) and D10. Patients with a positive peritoneal fluid yeast culture (YP) were compared to those with a negative yeast culture (YN). The evolution of serum BDG was compared in the two groups. Seventy patients were included (sixty-five analyzed): YP group (n = 19) and YN group (n = 46). Median peritoneal BDG concentration during surgery was 2890 pg.mL⁻¹ [IQR: 942–12,326] in the YP group vs. 1202 pg.mL⁻¹ [IQR: 317–4223] in the YN group (p = 0.13). Initial serum BDG concentration was 130 pg.mL⁻¹ [IQR: 55–259] in the YP group vs. 88 pg.mL⁻¹ [IQR: 44–296] in the YN group (p = 0.78). No difference in evolution of serum BDG concentrations was observed between the groups (p = 0.18). In conclusion, neither peritoneal BDG nor serum BDG appear to be good discriminating markers for the diagnosis of yeast IAI. In addition, monitoring the evolution of serum BDG in yeast IAI did not appear to be of any diagnostic value.

Increased mortality and altered local immune response in secondary peritonitis after previous visceral operations in mice

Postoperative peritonitis is characterized by a more severe clinical course than other forms of secondary peritonitis. The pathophysiological mechanisms behind this phenomenon are incompletely understood. This study used an innovative model to investigate these mechanisms, combining the models of murine Colon Ascendens Stent Peritonitis (CASP) and Surgically induced Immune Dysfunction (SID). Moreover, the influence of the previously described anti-inflammatory reflex transmitted by the vagal nerve was characterized. SID alone, or 3 days before CASP were performed in female C57BL/6 N mice. Subdiaphragmatic vagotomy was performed six days before SID with following CASP. The immune status was assessed by FACS analysis and measurement of cytokines. Local intestinal inflammatory changes were characterized by immunohistochemistry. Mortality was increased in CASP animals previously subjected to SID. Subclinical bacteremia occurred after SID, and an immunosuppressive milieu occurred secondary to SID just before the induction of CASP. Previous SID modified the pattern of intestinal inflammation induced by CASP. Subdiaphragmatic vagotomy had no influence on sepsis mortality in our model of postoperative peritonitis. Our results indicate a surgery-induced inflammation of the small intestine and the peritoneal cavity with bacterial translocation, which led to immune dysfunction and consequently to a more severe peritonitis.

The effect of glutathione as adjuvant therapy on levels of TNF-α and IL-10 in wistar rat peritonitis model

Background

Peritonitis is the second most common cause of severe sepsis that associated with a significant mortality rate. Due to a large gap of newer antibiotics innovation and antibiotic resistance emergence, the use of antioxidant has a possible alternative as adjuvant therapy in peritonitis management. It has been studied that glutathione as an alternative in the development of new anti-inflammatory effect. Thus, the aim of this study was to evaluate the levels of TNF-α and IL-10 after glutathione administration as adjuvant therapy in rat peritonitis model.

Materials and methods

Male wistar rats were divided into four groups (n = 6 per group), Group 1: control group (C), Group 2: peritonitis group (P), Group 3: peritonitis + Ceftriaxone group (P + Cef), Group 4: peritonitis + Ceftriaxone + Glutathione group (P + Cef + Glu). Twenty-four hours after peritonitis induction, the blood samples were taken to evaluate TNF-α and IL-10 levels.

Results

There was a significantly increase of mean TNF-α level in group 2 (P) 473,86 ± 388,99 pg/ml (p value 0,00) and significantly decrease of mean TNF-α level after glutathione injection in group 4 (P + Cef + Glu) (p value 0,02). No significant changes in IL-10 levels in rats peritonitis model.

Conclusions

Glutathione supplementation is significantly decrease the mean level of TNF-α in rats induced peritonitis, however there is no difference compare to antibiotic only. Moreover, there no significant changes level of IL-10 in rats induced peritonitis after glutathione injection.

Early Procalcitonin Assessment in the Emergency Department in Patients with Intra-Abdominal Infection: An Excess or a Need?

Background: Intra-abdominal infection (IAI) is a wide range of intra-abdominal disease. Management involves empirical therapy and source control. Procalcitonin (PCT) has been suggested to assist in defining individual infection status and delivering individualized therapy. The aim of this study was to investigate the effects on patient outcomes of an early procalcitonin (PCT) assessment (in the emergency department [ED]) in patients with IAI. Methods: This was a retrospective, mono-centric study evaluating consecutive patients admitted to the ED from 2015 to 2019 with diagnosis of IAI. According to whether there had been PCT determination in the ED, patients were divided into no ePCT determination (no-ePCT) and early PCT determination in the ED (ePCT). The primary endpoint was the intra-hospital mortality rate. Secondary endpoints were occurrence of major complications and length of hospital stay (LOS). The propensity score match (PSM) was generated using a logistic regression model on the baseline covariates considered to be potentially influencing the decision to determine PCT in the ED and confounding factors identified as significant at a preliminary statistical analysis with respect to in-hospital death. Results: A series of 3,429 patients were included. The ePCT group consisted to 768 (22.4%), whereas the no-ePCT group contained 2,661 patients (77.6%). When the PSM was matched to the two groups, no significant difference was observed. Considering patients with uncomplicated infections, the PCT determination was associated with a higher mortality rate. We found no significant differences regarding outcomes with the exception of LOS, which was slightly longer in the ePCT group. However, we observed a tendency toward a minor difference in the number of complications in the ePCT group, in particular a reduced rate of progression to sepsis. Conclusion: Early PCT determination could be irrelevant in IAIs. The PCT value may be cost-effective and possibly improve the prognosis in cIAIs. Further research is needed to understand the optimal use of PCT, including in combination with other emerging diagnostic tests.

[99m Tc-HYNIC/EDDA]-MccJ25 antimicrobial peptide analog as a potential radiotracer for detection of infection

Bacterial infections are a serious risk to human health, and therefore techniques for early detection of infectious foci need to be further developed to begin treatment quickly and achieve better results. Antimicrobial peptides labeled with gamma-emission radio nuclides are important diagnostic radiotracers in nuclear medicine. This study was conducted to evaluate the potential of a ^99m Tc-labeled MicrocinJ25 (MccJ25) antimicrobial peptide analog for early detection of infection. For this purpose, a HYNIC conjugated cyclic peptide derivative based on the primary structure of MccJ25 peptide was prepared and labeled by ^99m Tc with tricine and EDDA as coligands. The [^99m Tc-HYNIC/EDDA]-MccJ25 peptide analog showed high radiochemical purity (˃90% (n = 5)) which was stable up to 24 hr after labeling. The radiotracer showed specific uptake to the Escherichia coli (E. coli) bacterial (40.45 ± 5.21%) at 1 hr incubation. High kidneys uptake of radioactivity (4.71 ± 0.84% and 3.76 ± 0.45% ID/g at 1 and 4 hr after injection respectively) demonstrates that most of the whole body clearance was proceeded via the urinary system. Significant radioactivity uptake (1.71 ± 0.34%ID/g) was observed in thigh muscle of mouse with E. coli induced infection at 1 hr after injection. In the blocking test, due to the significant decrease of radioactivity uptake in the infection site (0.62 ± 0.21%ID/g after 1 hr), the specificity of infection uptake was reviled. Despite the high activity of the bladder due to urinary excretion, the infected area was somewhat visible. Hence, the results indicate the potential of this new radiotracer to be used as a diagnostic agent in E. coli infections.

Trends in Antibiotic Duration for Complicated Intra-Abdominal Infections : Adaptation to Current Guidelines

INTRODUCTION

The 2017 surgical infection society (SIS) guidelines recommend 4 days of antibiotic therapy after source control for complicated intra-abdominal infections (cIAIs). Inappropriate exposure to antibiotics has a negative impact on outcomes in individual patients and populations. The goal of this study was to evaluate our institution's practice patterns and adherence to current antibiotic guidelines.

METHODS

Medical records from 2010 to 2018 for cIAIs were examined. Complicated appendicitis and complicated diverticulitis cases were included. Exclusion criteria included other etiologies of IAIs, pediatric cases, and cancer operations.

RESULTS

Fifty-nine complicated appendicitis cases and 96 complicated diverticulitis cases were identified. For all cases, antibiotic duration prior to publication of the SIS guidelines was significantly longer than post-SIS duration (appendicitis: 12.6 ± 1.1 days pre-SIS [n = 37] vs 9.0 ± 1.1 days post-SIS [n = 22], P = .01; diverticulitis: 15.1 ± 0.8 days pre-SIS [n = 49] vs 11.2 ± 0.5 post-SIS [n = 47], P = .04). Surgical management (SM) was associated with shorter duration of postsource control antibiotic exposure compared with percutaneous drainage (PD) for both appendicitis (SM 10.0 ± 1.2 days vs PD 13.4 ± 1.0 days, P = .02) and diverticulitis (SM 12.8 ± 1.5 days vs PD 16.0 ± 1.5, P = .07). Patients with complicated appendicitis received shorter duration of antibiotics when managed by acute care surgeons compared to general surgeons (8.4 ± 1.1 vs 11.9 ± 0.8, P = .02).

CONCLUSION

Despite improvements after the SIS guidelines' publication, the antibiotic duration is still longer than recommended. Surgical intervention and management by acute care specialists were associated with a shorter duration of antibiotic exposure.

Antimicrobial Susceptibility of Microorganisms Isolated from Patients with Intraabdominal Infection in Korea: a Multicenter Study

BACKGROUND

This study evaluated the antimicrobial susceptibility of pathogens isolated from Korean patients with intraabdominal infections (IAIs).

METHODS

This multicenter study was conducted at 6 university-affiliated hospitals in Korea between 2016 and 2018. All patients with microbiologically proven IAIs were retrospectively included, while patients with spontaneous bacterial peritonitis or continuous ambulatory peritoneal dialysis peritonitis were excluded. Identification and antimicrobial susceptibility testing were performed using automated microbiology systems.

RESULTS

A total of 2,114 non-duplicated clinical isolates were collected from 1,571 patients. Among these pathogens, 510 (24.1%) were isolated from nosocomial infections, and 848 isolates (40.1%) were associated with complicated IAIs. The distribution of the microorganisms included aerobic gram-negative (62.6% of isolates), aerobic gram-positive (33.7%), anaerobic (0.9%), and fungal (2.8%) pathogens. The most common pathogens were Escherichia coli (23.8%), followed by Enterococcus spp. (23.1%) and Klebsiella spp. (19.8%). The susceptibility rates of E. coli and Klebsiella spp. to major antibiotics were as follows: amoxicillin/clavulanate (62.5%, 83.0%), cefotaxime (61.4%, 80.7%), ceftazidime (63.7%, 83.1%), cefepime (65.3%, 84.3%), ciprofloxacin (56.4%, 86.3%), piperacillin/tazobactam (99.0%, 84.8%), amikacin (97.4%, 98.3%), and imipenem (99.8%, 98.8%). The susceptibility rates of Enterococcus spp. to ampicillin were 61.0%, amoxicillin/clavulanate, 63.6%; ciprofloxacin, 49.7%; imipenem, 65.2%; and vancomycin, 78.2%. The susceptibility rates of Pseudomonas aeruginosa and Acinetobacter spp. to imipenem were 77.4% and 36.7%, respectively.

CONCLUSION

Enterococcus spp. with susceptibility to limited antibiotics was one of the main pathogens in Korean IAIs, along with E. coli and Klebsiella spp., which were highly susceptible to imipenem, amikacin, and piperacillin/tazobactam. Meanwhile, the low susceptibilities of E. coli or Klebsiella spp. to amoxicillin/clavulanate, advanced-generation cephalosporins, and ciprofloxacin should be considered when determining empirical antibiotic therapy in clinical practice.

Intra-abdominal infections: the role of different classifications on the selection of the best antibiotic treatment

Background

Intra-abdominal infections (IAIs) represent a most frequent gastrointestinal emergency and serious cause of morbimortality. A full classification, including all facets of IAIs, does not exist. Two classifications are used to subdivide IAIs: uncomplicated or complicated, considering infection extent; and community-acquired, healthcare-associated or hospital-acquired, regarding the place of acquisition. Adequacy of initial empirical antibiotic therapy prescribed is an essential need. Inadequate antibiotic therapy is associated with treatment failure and increased mortality. This study was designed to determine accuracy of different classifications of IAIs to identify infections by pathogens sensitive to current treatment guidelines helping the selection of the best antibiotic therapy.

Methods

A retrospective cohort study including all adult patients discharged from hospital with a diagnosis of IAI between 1st of January and 31st of October, 2016. All variables potentially associated with pre-defined outcomes: infection by a pathogen sensitive to non-pseudomonal cephalosporin or ciprofloxacin plus metronidazole (ATB 1, primary outcome), sensitive to piperacillin-tazobactam (ATB 2) and hospital mortality (secondary outcomes) were studied through logistic regression. Accuracy of the models was assessed by area under receiver operating characteristics (AUROC) curve and calibration was tested using the Hosmer-Lemeshow goodness-of-fit test.

Results

Of 1804 patients screened 154 met inclusion criteria. Sensitivity to ATB 1 was independently associated with male gender (adjusted OR = 2.612) and previous invasive procedures in the last year (adjusted OR = 0.424) (AUROC curve = 0,65). Sensitivity to ATB 2 was independently associated with liver disease (adjusted OR = 3.580) and post-operative infections (adjusted OR = 2.944) (AUROC curve = 0.604). Hospital mortality was independently associated with age ≥ 70 (adjusted OR = 4.677), solid tumour (adjusted OR = 3.127) and sensitivity to non-pseudomonal cephalosporin or ciprofloxacin plus metronidazole (adjusted OR = 0.368).

The accuracy of pre-existing classifications to identify infection by a pathogen sensitive to ATB 1 was 0.59 considering place of acquisition, 0.61 infection extent and 0.57 local of infection, for ATB 2 it was 0.66, 0.50 and 0.57, respectively.

Conclusion

None of existing classifications had a good discriminating power to identify IAIs caused by pathogens sensitive to current antibiotic treatment recommendations. A new classification, including patients’ individual characteristics like those included in the current model, might have a higher potential to distinguish IAIs by resistant pathogens allowing a better choice of empiric antibiotic therapy.

Candida albicans Impacts Staphylococcus aureus Alpha-Toxin Production via Extracellular Alkalinization

Candida albicans and Staphylococcus aureus are common causes of nosocomial infections with severe morbidity and mortality. Murine polymicrobial intra-abdominal infection (IAI) with C. albicans and S. aureus results in acute mortality dependent on the secreted cytolytic effector alpha-toxin. Here, we confirmed that alpha-toxin is elevated during polymicrobial growth compared to monomicrobial growth in vitro Therefore, this study sought to unravel the mechanism by which C. albicans drives enhanced staphylococcal alpha-toxin production. Using a combination of functional and genetic approaches, we determined that an intact agr quorum sensing regulon is necessary for enhanced alpha-toxin production during coculture and that a secreted candidal factor likely is not implicated in elevating agr activation. As the agr system is pH sensitive, we observed that C. albicans raises the pH during polymicrobial growth and that this correlates with increased agr activity and alpha-toxin production. Modulation of the pH could predictably attenuate or activate agr activity during coculture. By using a C. albicans mutant deficient in alkalinization (stp2Δ/Δ), we confirmed that modulation of the extracellular pH by C. albicans can drive agr expression and toxin production. Additionally, the use of various Candida species (C. glabrata, C. dubliniensis, C. tropicalis, C. parapsilosis, and C. krusei) demonstrated that those capable of raising the extracellular pH correlated with elevated agr activity and alpha-toxin production during coculture. Overall, we demonstrate that alkalinization of the extracellular pH by the Candida species leads to sustained activation of the staphylococcal agr system.IMPORTANCE Candida albicans and Staphylococcus aureus are commonly coisolated from central venous catheters and deep-seated infections, including intra-abdominal sepsis. Thus, they represent a significant cause of nosocomial morbidity and mortality. Yet how these organisms behave in the context of polymicrobial growth remains poorly understood. In this work, we set out to determine the mechanism by which activation of the staphylococcal agr quorum sensing system and production of its major virulence effector alpha-toxin is enhanced during coculture with C. albicans Surprisingly, we likely ruled out that a secreted candidal factor drives this process. Instead, we demonstrated that alkalinization of the extracellular milieu by C. albicans and other Candida species correlated with elevated agr activity. Thus, we propose a mechanism where modulation of the extracellular pH by fungal opportunists can indirectly alter virulence of a bacterial pathogen. Uncovering molecular events that drive interkingdom pathogenicity mechanisms may enhance surveillance and treatment for devastating polymicrobial infections.

Candida albicans and Staphylococcus aureus Pathogenicity and Polymicrobial Interactions: Lessons beyond Koch's Postulates

While Koch's Postulates have established rules for microbial pathogenesis that have been extremely beneficial for monomicrobial infections, new studies regarding polymicrobial pathogenesis defy these standards. The explosion of phylogenetic sequence data has revolutionized concepts of microbial interactions on and within the host. However, there remains a paucity of functional follow-up studies to delineate mechanisms driven by such interactions and how they shape health or disease. That said, one particular microbial pairing, the fungal opportunist Candida albicans and the bacterial pathogen Staphylococcus aureus, has received much attention over the last decade. Therefore, the objective of this review is to discuss the multi-faceted mechanisms employed by these two ubiquitous human pathogens during polymicrobial growth, including how they: establish and persist in inter-Kingdom biofilms, tolerate antimicrobial therapy, co-invade host tissue, exacerbate quorum sensing and staphylococcal toxin production, and elicit infectious synergism. Commentary regarding new challenges and remaining questions related to future discovery of this fascinating fungal-bacterial interaction is also provided.

Poor Outcome Could Be Predicted by Lower Monocyte Human Leukocyte Antigen-DR Expression in Patients with Complicated Intra-Abdominal Infections: A Review

Complicated intra-abdominal infections (cIAIs) are still associated with high morbidity and mortality levels. Early prognostic evaluation is a great challenge, and a serious amount of resources have been used to find the perfect mortality predictor. Monocyte human leukocyte antigen-DR (mHLA-DR) expression has been studied as a biomarker in patients with sepsis and other infections. Our aim was to evaluate the potential prognostic performance of mHLA-DR in patients with cIAIs. Methods: We performed an electronic search of Google Scholar and PubMed databases for articles published before January 2019. The search terms were "HLA-DR," "monocyte HLA-DR," "intra-abdominal infections," "sepsis," "outcome," and "mortality." Results: A total of 12 studies with 761 patients met our inclusion criteria. In 10 studies, poor outcome was predicted by lower mHLA-DR expression, and two studies showed no prognostic value. Conclusion: This review found association between lower mHLA-DR expression and mortality. We concluded that mHLA-DR could be a reliable and meaningful predictor of poor outcome in patients with cIAIs. Nevertheless, more large prospective studies with surgical patients exclusively are needed before using this biomarker in a clinical setting.

Antimicrobial susceptibility patterns of organisms causing secondary abdominal infections in patients with perforated abdominal viscus

Background:

Secondary peritonitis, following intestinal perforation, constitutes a significant proportion of cases admitted as a surgical emergency and has a mortality rate of 6–21% worldwide. As a part of an antimicrobial stewardship program, we noted considerable variation among the choice of empirical regimens among such cases. Hence, we conducted a prospective study to generate the evidence for a rational empiric regimen for patients with secondary peritonitis following intestinal perforation.

Methods:

The study included a complete follow up of 77 cases of secondary peritonitis admitted during a 12 month period. The intraoperative fluid (peritoneal) sample of the patient was sent for culture and sensitivity pattern analysis.

Results:

The sites of perforation as seen in decreasing order were lower gastrointestinal (GI) (50.6%), upper GI (36.4%), and unclassified (13%). The most common organism found in the intraoperative fluid was Escherichia coli (47.9%) followed by Klebsiella pneumoniae (12.5%). amikacin, cefoperazone-sulbactam, piperacillin-tazobactam and imipenem were sensitive in 22 (out of 23 tested), 5 (out of 9), 13 (out of 13) and 22 (out of 22) isolates of E. coli and 3 (out of 6), 1 (out of 3), 4 (out of 6), 4 (out of 6) isolates of K. pneumoniae, respectively. The most common empirical antibiotic was cefoperazone-sulbactam (38.7%) followed by piperacillin-tazobactam (29.3%).

Conclusion:

Based on our prospective study, piperacillin-tazobactam or imipenem should be used empirically in patients presenting with complicated intra-abdominal infections secondary to perforated viscus, especially if they have sepsis or septic shock.

An Evaluation of Guideline Concordance in the Management of Intra-Abdominal Infections

Background: Optimal treatment of intra-abdominal infections (IAIs) is multifaceted, typically requiring surgical intervention and antimicrobial therapy. Treatment of IAIs aligned with the 2017 revised Surgical Infection Society (SIS) guidelines may improve patient outcomes. Here we compare clinical outcomes of patients who received guideline concordant and discordant therapy for treatment of IAIs. Patients and Methods: This was a retrospective observational study of patients admitted from January 2013 to June 2016 with IAIs. Guideline concordant treatment was based on three criteria: source control, antibiotic choice, and antibiotic duration. The primary outcome was a composite of in-hospital mortality and 30-day re-admission. Multivariable logistic regression was used to determine independent factors associated with the composite end point. Results: A total of 221 patients were included, with guideline concordant treatment occurring in 117 (53%) patients. In-hospital mortality or 30-day re-admission occurred in 15 (12.8%) patients in the guideline concordant group compared with 24 (23.1%) in the guideline discordant group (p = 0.046). Empiric antibiotic choice was the most common component of discordance to guidelines (61% of patients). In multivariable analysis, guideline concordant treatment was associated with a decrease in the composite outcome (adjusted odds ratio [aOR] = 0.461, p = 0.045). In contrast, the presence of empiric methicillin-resistant Staphylococcus aureus (MRSA)/vancomycin-resistant Enterococcus (VRE) coverage (aOR: 2.645, p = 0.030), and moderate-to-severe liver disease (aOR: 8.081, p = 0.027) were associated with an increased risk for the composite outcome. Conclusions: Concordance to recommendations from the 2017 revised SIS guidelines is of critical importance in the optimal management of IAIs and further investigation of interventions to improve concordance are warranted.

The 2018 Lebanese Society of Infectious Diseases and Clinical Microbiology Guidelines for the use of antimicrobial therapy in complicated intra-abdominal infections in the era of antimicrobial resistance

BACKGROUND

The Lebanese Society of Infectious Diseases and Clinical Microbiology (LSIDCM) is involved in antimicrobial stewardship. In an attempt at guiding clinicians across Lebanon in regards to the proper use of antimicrobial agents, members of this society are in the process of preparing national guidelines for common infectious diseases, among which are the guidelines for empiric and targeted antimicrobial therapy of complicated intra-abdominal infections (cIAI). The aims of these guidelines are optimizing patient care based on evidence-based literature and local antimicrobial susceptibility data, together with limiting the inappropriate use of antimicrobials thus decreasing the emergence of antimicrobial resistance (AMR) and curtailing on other adverse outcomes.

METHODS

Recommendations in these guidelines are adapted from other international guidelines but modeled based on locally derived susceptibility data and on the availability of pharmaceutical and other resources.

RESULTS

These guidelines propose antimicrobial therapy of cIAI in adults based on risk factors, site of acquisition of infection, and clinical severity of illness. We recommend using antibiotic therapy targeting third-generation cephalosporin (3GC)-resistant gram negative organisms, with carbapenem sparing as much as possible, for community-acquired infections when the following risk factors exist: prior (within 90 days) exposure to antibiotics, immunocompromised state, recent history of hospitalization or of surgery and invasive procedure all within the preceding 90 days. We also recommend antimicrobial de-escalation strategy after culture results. Prompt and adequate antimicrobial therapy for cIAI reduces morbidity and mortality; however, the duration of therapy should be limited to no more than 4 days when adequate source control is achieved and the patient is clinically stable. The management of acute pancreatitis is conservative, with a role for antibiotic therapy only in specific situations and after microbiological diagnosis. The use of broad-spectrum antimicrobial agents including systemic antifungals and newly approved antibiotics is preferably restricted to infectious diseases specialists.

CONCLUSION

These guidelines represent a major step towards initiating a Lebanese national antimicrobial stewardship program. The LSIDCM emphasizes on development of a national AMR surveillance network, in addition to a national antibiogram for cIAI stratified based on the setting (community, hospital, unit-based) that should be frequently updated.

The impact of initial antibiotic treatment failure: real-world insights in patients with complicated, health care-associated intra-abdominal infection

Purpose

The RECOMMEND study (NCT02364284; D4280R00005) assessed the clinical management patterns and treatment outcomes associated with initial antibiotic therapy (IAT; antibiotics administered ≤48 hours post-initiation of antibiotic therapy) for health care-associated infections across five countries.

Patients and methods

Data were collected from a retrospective chart review of patients aged ≥18 years with health care-associated complicated intra-abdominal infection (cIAI). Potential risk factors for IAT failure were identified using logistic regression analyses.

Results

Of 385 patients with complete IAT data, bacterial pathogens were identified in 270 (70.1%), including Gram-negative isolates in 221 (81.9%) and Gram-positive isolates in 92 (34.1%). Multidrug-resistant (MDR) pathogens were identified in 112 patients (41.5% of patients with a pathogen identified). IAT failure rate was 68.3% and in-hospital mortality rate was 40.8%. Multivariate regression analysis demonstrated three factors to be significantly associated with IAT failure: patients admitted/transferred to the intensive care unit during index hospitalization, isolation of an MDR pathogen and previous treatment with β-lactam antibiotics.

Conclusion

We reveal the real-world insights into the high rates of IAT failure and mortality observed among patients with cIAI. These data highlight the challenges associated with choosing IAT, the impact of MDR pathogens on IAT outcomes and the importance of tailoring IAT selection to account for local epidemiology and patient history.

Fluoroquinolone-based versus β-lactam-based regimens for complicated intra-abdominal infections: a meta-analysis of randomised controlled trials

Complicated intra-abdominal infections (cIAIs) are common and confer significant morbidity, mortality and costs. In this era of evolving antimicrobial resistance, selection of appropriate empirical antimicrobials is paramount. This systematic review and meta-analysis of randomised controlled trials compared the effectiveness and safety of fluoroquinolone (FQ)-based versus β-lactam (BL)-based regimens for the treatment of patients with cIAIs. Primary outcomes were treatment success in the clinically evaluable (CE) population and all-cause mortality in the intention-to-treat (ITT) population. Subgroup analyses were performed based on specific antimicrobials, infection source and isolated pathogens. Seven trials (4125 patients) were included. FQ-based regimens included moxifloxacin (four studies) or ciprofloxacin/metronidazole (three studies); BL-based regimens were ceftriaxone/metronidazole (three studies), carbapenems (two studies) or piperacillin/tazobactam (two studies). There was no difference in effectiveness in the CE (2883 patients; RR = 1.00, 95% CI 0.95-1.04) or ITT populations (3055 patients; RR = 0.97, 95% CI 0.94-1.01). Mortality (3614 patients; RR = 1.04, 95% CI 0.75-1.43) and treatment-related adverse events (2801 patients; RR = 0.97, 95% CI 0.70-1.33) were also similar. On subset analysis, moxifloxacin was slightly less effective than BLs in the CE (1934 patients; RR = 0.96, 95% CI 0.93-0.99) and ITT populations (1743 patients; RR = 0.94, 95% CI 0.91-0.98). Although FQ- and BL-based regimens appear equally effective and safe for the treatment of cIAIs, limited data suggest slightly inferior results with moxifloxacin. Selection of empirical coverage should be based on local bacterial epidemiology and patterns of resistance as well as antimicrobial stewardship protocols.

Early Versus Delayed Source Control in Open Abdomen Management for Severe Intra-abdominal Infections: A Retrospective Analysis on 111 Cases

BACKGROUND

Time to source control plays a determinant prognostic role in patients having severe intra-abdominal infections (IAIs). Open abdomen (OA) management became an effective treatment option for peritonitis. Aim of this study was to analyze the correlation between time to source control and outcome in patients presenting with abdominal sepsis and treated by OA.

METHODS

We retrospectively analyzed 111 patients affected by abdominal sepsis and treated with OA from May 2007 to May 2015. Patients were classified according to time interval from first patient evaluation to source control. The end points were intra-hospital mortality and primary fascial closure rate.

RESULTS

The in-hospital mortality rate was 21.6% (24/111), and the primary fascial closure rate was 90.9% (101/111). A time to source control ≥6 h resulted significantly associated with a poor prognosis and a lower fascial closure rate (mortality 27.0 vs 9.0%, p = 0.04; primary fascial closure 86 vs 100%, p = 0.02). We observed a direct increase in mortality (and a reduction in closure rate) for each 6-h delay in surgery to source control.

CONCLUSION

Early source control using OA management significantly improves outcome of patients with severe IAIs. This damage control approach well fits to the treatment of time-related conditions, particularly in case of critically ill patients.

The appropriateness of ceftriaxone and metronidazole as empirical therapy in managing complicated intra-abdominal infection-experience from Western Health, Australia

Purpose

This study aims to assess the microbiological profile, antimicrobial susceptibility and adequacy of intravenous ceftriaxone and metronidazole as empirical therapy for surgical patients presenting with complicated intra-abdominal infection.

Methods

This retrospective audit reviews the microbiological profile and sensitivity of intra-abdominal cultures from adult patients with complicated intra-abdominal infection who presented to the emergency department at Western Health (Melbourne, Australia) between November 2013 and June 2017. Using the hospital’s database, an audit was completed using diagnosis related group (DRG) coded data. Ethics approval has been granted by the Western Health Human Research Ethics Committee. Results are stratified according to surgical conditions (appendicitis, cholecystitis, sigmoid diverticulitis and bowel perforation). The antimicrobial coverage of ceftriaxone and metronidazole is evaluated against these microbial profiles.

Results

A total of 1,412 patients were identified using DRG codes for intra-abdominal infection. All patients with microscopy and sensitivity results were included in the study. Patients without these results were excluded. 162 patients were evaluable. 180 microbiological cultures were performed through surgical intervention or radiologically guided aspiration of the intra-abdominal infection. Single or multiple pathogens were identified in 137 cultures. The most commonly identified pathogens were mixed anaerobes (12.6%), Escherichia coli (E. coli) (12.1%), mixed coliforms (11.6%) and Pseudomonas aeruginosa (7%). Other common pathogens (6% each) included Enterococcus faecalis, Streptococcus anginosus, Vancomycin-resistant Enterococci (VRE) and Extended Spectrum Beta-Lactamases (ESBL) producing E. coli. Organisms isolated in our study are consistent with existing literature. However, a significant proportion of antibiotic resistant organisms was identified in cases of perforated bowel and sigmoid diverticulitis. Broader spectrum antimicrobial therapy should therefore be considered in lieu of ceftriaxone and metronidazole in these cases. Ceftriaxone and metronidazole remain as appropriate empirical therapy for patients who presented with perforated appendicitis and cholecystitis.

Discussion

The empirical regime of ceftriaxone and metronidazole remains appropriate for intra-abdominal infection secondary to appendicitis and cholecystitis. In cases involving perforated small and large bowel, including complicated sigmoid diverticulitis, the judicious use of ceftriaxone and metronidazole is recommended.

Identification of Specific Components of the Eicosanoid Biosynthetic and Signaling Pathway Involved in Pathological Inflammation during Intra-abdominal Infection with Candida albicans and Staphylococcus aureus

Polymicrobial intra-abdominal infections (IAIs) are a significant cause of morbidity and mortality, particularly when fungal pathogens are involved. Our experimental murine model of IAI involving intraperitoneal inoculation of Candida albicans and Staphylococcus aureus results in synergistic lethality (∼80%) due to exacerbated inflammation. Monomicrobial infection results in no mortality, despite a microbial burden and dissemination similar to those in a coinfection. In the coinfection model, the immunomodulatory eicosanoid prostaglandin E₂ (PGE₂) was determined to be necessary and sufficient to induce mortality, implicating PGE₂ as the central mediator of the amplified inflammatory response. The aim of this study was to identify key components of the PGE₂ biosynthetic and signaling pathway involved in the inflammatory response and explore whether these can be targeted to prevent or reduce mortality. Using selective pharmacological inhibitors of cyclooxygenases (COX) or PGE₂ receptor antagonists in the C. albicans-S. aureus IAI mouse model, we found that inhibition of COX and/or blocking of PGE₂ receptor 1 (EP1) or PGE₂ receptor 3 (EP3) signaling reduced proinflammatory cytokine production, promoted interleukin-10 production, reduced cellular damage in the peritoneal cavity, and, most importantly, significantly improved survival. The greatest effect on survival was obtained by the simultaneous inhibition of COX-1 activity and EP1 and EP3 receptor signaling. Importantly, early inhibition of PGE₂ pathways dramatically improved the survival of fluconazole-treated mice compared with that achieved with fluconazole treatment alone. These findings indicate that COX-1 and the EP1 and EP3 receptors mediate the downstream pathological effects of PGE₂ during polymicrobial IAI and may serve as effective therapeutic targets.

Circulating stem cells, HIF-1, and SDF-1 in septic abdominal surgical patients: randomized controlled study protocol

Background

Sepsis caused by complicated intra-abdominal infection is associated with high mortality. Loss of endothelial barrier integrity, inflammation, and impaired cellular oxygen have been shown to be primary contributors to sepsis. To date, little is known regarding the pathway for the mobilization of endothelial progenitor cells (EPCs) from the bone marrow in sepsis whereas stromal-cell-derived factor 1a (SDF-1a) and hypoxia inducible factor 1 (HIF-1) seem to have a role in the EPC response to hypoxic microenvironments.

The aims of the study are: (a) to determine the time course of the levels of circulating EPCs (CD133/CD34), SDF-1a, and HIF-1 in septic patients undergoing major abdominal surgery (group S), (b) to investigate the relationship between CD133/CD34, HIF-1, and SDF-1a, and (c) to investigate the relationship of these factors with the outcome of group S patients treated with standard conventional therapy alone (CT) or with the addition of extracorporeal hemoperfusion therapy (HCT).

Methods/design

Patients undergoing major abdominal surgery will be allocated into groups: postoperative non-septic patients in an emergency surgical ward (group C) and postoperative septic patients in an intensive care unit (group S). The latter will be randomized to receive CT alone (S1) or with HCT (S2). Healthy volunteers (group H) will be recruited at University Hospital Foggia.

Peripheral blood (PB) samples will be collected preoperatively (T0), at 24 h (T1), 72 h (T2), 7 (T3), and 10 (T4) postoperative days in groups S and C, and at T0 in group H. The CD34/133 cells and HIF-1 counts will be determined by flow cytometer analysis. The concentration of SDF-1a in plasma will be calculated by enzyme-linked immunosorbent assay analysis (ELISA).

Discussion

This prospective randomized clinical trial is designed to investigate circulating stem cells, levels of HIF-1 and SDF-1a, and their interrelationship in septic postoperative abdominal surgical patients treated with CT alone or with HCT. The rationale is that an integrated understanding of the role of hypoxia-related factors and EPCs in PB of septic patients could indicate which molecular processes need to be regulated to recover the innate immunity homeostasis. Understanding the function of EPCs in sepsis may provide innovative diagnostic and therapeutic approaches to improve the prognosis of this syndrome.

Trial registration

ClinicalTrials.gov: NCT02589535. Registered on 28 October 2015.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2556-0) contains supplementary material, which is available to authorized users.

Update of incidence and antimicrobial susceptibility trends of Escherichia coli and Klebsiella pneumoniae isolates from Chinese intra-abdominal infection patients

Background

To evaluate in vitro susceptibilities of aerobic and facultative Gram-negative bacterial (GNB) isolates from intra-abdominal infections (IAIs) to 12 selected antimicrobials in Chinese hospitals from 2012 to 2014.

Methods

Hospital acquired (HA) and community acquired (CA) IAIs were collected from 21 centers in 16 Chinese cities. Extended spectrum beta-lactamase (ESBL) status and antimicrobial susceptibilities were determined at a central laboratory using CLSI broth microdilution and interpretive standards.

Results

From all isolated strains the Enterobacteriaceae (81.1%) Escherichia coli accounted for 45.4% and Klebsiella pneumoniae for 20.1%, followed by Enterobacter cloacae (5.2%), Proteus mirabilis (2.1%), Citrobacter freundii (1.8%), Enterobacter aerogenes (1.8%), Klebsiella oxytoca (1.4%), Morganella morganii (1.2%), Serratia marcescens (0.7%), Citrobacter koseri (0.3%), Proteus vulgaris (0.3%) and others (1.0%). Non- Enterobacteriaceae (18.9%) included Pseudomonas aeruginosa (9.8%), Acinetobacter baumannii (6.7%), Stenotrophomonas maltophilia (0.9%), Aeromonas hydrophila (0.4%) and others (1.1%). ESBL-screen positive Escherichia coli isolates (ESBL+) showed a decreasing trend from 67.5% in 2012 to 58.9% in 2014 of all Escherichia coli isolates and the percentage of ESBL+ Klebsiella pneumoniae isolates also decreased from 2012 through 2014 (40.4% to 26.6%), which was due to reduced percentages of ESBL+ isolates in HA IAIs for both bacteria. The overall susceptibilities of all 5160 IAI isolates were 87.53% to amikacin (AMK), 78.12% to piperacillin-tazobactam (TZP) 81.41% to imipenem (IMP) and 73.12% to ertapenem (ETP). The susceptibility of ESBL-screen positive Escherichia coli strains was 96.77%–98.8% to IPM, 91.26%–93.16% to ETP, 89.48%–92.75% to AMK and 84.86%–89.34% to TZP, while ESBL-screen positive Klebsiella pneumoniae strains were 70.56%–80.15% susceptible to ETP, 80.0%–87.5% to IPM, 83.82%–87.06% to AMK and 63.53%–68.38% to TZP within the three year study. Susceptibilities to all cephalosporins and fluoroquinolones were less than 50% beside 66.5% and 56.07% to cefoxitin (FOX) for ESBL+ Escherichia coli and Klebsiella pneumoniae strains respectively.

Conclusions

The total ESBL+ rates decreased in Escherichia coli and Klebsiella pneumoniae IAI isolates due to fewer prevalence in HA infections. IPM, ETP and AMK were the most effective antimicrobials against ESBL+ Escherichia coli and Klebsiella pneumoniae IAI isolates in 2012–2014 and a change of fluoroquinolone regimens for Chinese IAIs is recommended.

Electronic supplementary material

The online version of this article (10.1186/s12879-017-2873-z) contains supplementary material, which is available to authorized users.

Evaluation of a Short Course of Antimicrobial Therapy for Complicated Intra-Abdominal Infections in Critically Ill Surgical Patients

BACKGROUND

The optimal duration of antimicrobial therapy for treatment of complicated intra-abdominal infections (cIAI) in critically ill surgical patients is unknown. Recent evidence suggests that a short (four-day) course of therapy may be effective, however data in severely critically ill patients are limited.

PATIENTS AND METHODS

A single-center, retrospective, cohort study was conducted at a tertiary academic medical center. Adult patients admitted to the surgical intensive care unit (SICU) with cIAI between December 2011 and July 2015 were enrolled. Patients undergoing transplantation and those with less than 24 h in the SICU were excluded. Patients were divided into two groups, short (≤ 7 d) and long (> 7 d) antimicrobial therapy. The primary outcome was treatment failure, which was defined as a composite of recurrent cIAI, secondary extra-abdominal infection, and/or in-hospital mortality from any cause. Categorical and continuous data were analyzed with χ² and Mann-Whitney U tests, respectively. Binary logistic regression was performed to determine factors associated with treatment failure and mortality.

RESULTS

Of 1,679 patients screened, 240 were included, 103 in the short and 137 in the long group. Patients in the short and long groups received a median of 5 and 14 d of therapy, respectively (p < 0.001). Treatment failure occurred less frequently with a short duration of therapy (39% versus 63%, p < 0.001) and it occurred two days sooner after source control in patients receiving the shorter courses of antimicrobial therapy (short, median 6 d, interquartile range [IQR] 3-9; long, 8 d, IQR 6-14; p < 0.001). Logistic regression demonstrated that a long duration of therapy was associated with treatment failure (odds ratio [OR] 2.186, 95% confidence interval [CI] 1.251-3.820, p = 0.006), but not with mortality (OR 0.738, 95% CI 0.329-1.655, p = 0.461).

CONCLUSIONS

In critically ill surgical patients with cIAI, a short duration of antimicrobial therapy after source control resulted in similar outcomes to previously published studies, providing support for the safety of this approach in critically ill patients.

Role of the Open Abdomen in Critically Ill Patients

An open abdomen is common used in critically ill patients to temporize permanent abdominal closure. The most common reason for leaving the abdomen open by reopening a laparotomy, not closing, or creating a fresh laparotomy is the abdominal compartment syndrome. The open abdomen technique is also used in damage control operations and intra-abdominal sepsis. Negative pressure wound therapy may be associated with better outcomes than other temporary abdominal closure techniques. The open abdomen is associated with many early and late complications, including infections, gastrointestinal fistulas, and ventral hernias. Clinicians should be vigilant regarding the development of these complications.

[Pathophysiology of peritonitis]

Despite intensive research efforts peritonitis leading to subsequent sepsis remains associated with a high mortality. The initial effector cells are the locally residing cells of the peritoneum, such as mesothelial cells, mast cells, macrophages and lymphocytes. Through the secretion of chemokines, an influx of neutrophils initially takes place followed by monocytes. The latter can differentiate into inflammatory macrophages. The non-directed activity of neutrophilic granulocytes is limited by the induction of apoptotic programs. Through the breaching of cytokines, bacteria and microbial products into the circulation, a systemic reaction in the sense of systemic inflammatory response syndrome (SIRS) or sepsis arises. This is viewed as a concomitant derailing of inflammatory as well as anti-inflammatory responses, which leads to extensive apoptosis of lymphocytes. The presentation of apoptotic cells leads to a strong immunosuppression. Due to the coexistence of hyperinflammation and immunosuppression, exact knowledge of the current immune status of the patient is a prerequisite in the development of immunotherapies for the treatment of sepsis.

Impact of ventilator-associated pneumonia on mortality and epidemiological features of patients with secondary peritonitis

Background

Despite the significant impact of nosocomial infections on the morbidity and mortality of patients staying in the intensive care unit (ICU), no study over the past 20 years has focused specifically on VAP following secondary peritonitis. The objective of the present study was to determine in-hospital mortality and epidemiological features attributed to ventilator-associated pneumonia (VAP) following secondary peritonitis.

Methods

Prospective observational study involved 418 consecutive patients admitted in the ICU. Univariate and multivariate analyses were performed to identify risk factors associated with mortality and development of VAP.

Results

The incidence of VAP following secondary peritonitis was 9.6 %. Risk factors associated with the development of VAP were hospital-acquired peritonitis, requiring >48 h of mechanical ventilation, and SOFA score. The onset of VAP was late in majority of patients. VAP was developed about 16.8 days after the initiation of the peritonitis. Etiological microorganisms responsible for the peritonitis were different than for VAP. The 90-day in-hospital mortality rate was 47.5 % of VAP patients. Independent factors associated with 30- to 90-day in-hospital mortality were VAP and SOFA.

Conclusions

In light of the impact on morbidity and mortality in the ICU, more attention should be given to the concurrent features among VAP and secondary peritonitis.

Image-guided percutaneous drainage vs. surgical repair of gastrointestinal anastomotic leaks: is there a difference in hospital course or hospitalization cost?

PURPOSE

To identify differences in hospital course and hospitalization cost when comparing image-guided percutaneous drainage with surgical repair for gastrointestinal anastomotic leaks.

MATERIALS AND METHODS

A retrospective IRB-approved search using key words "leak" and/or "anastomotic" was performed on all adult CT reports from 2002 to 2011. CT examinations were reviewed for evidence of a postoperative gastrointestinal leak and assigned a confidence score of 1-5 (1 = no leak, 5 = definite leak). Patients with an average confidence score <4 were excluded. Type of surgery, patient data, method of leak management, number of hospital admissions, length of hospital stay, discharge disposition, number of CT examinations, number of drains, and hospitalization costs were collected.

RESULTS

One hundred thirty-nine patients had radiographic evidence of a gastrointestinal anastomotic leak (esophageal, gastric, small bowel or colonic). Nine patients were excluded due to low confidence scores. Twenty-seven patients underwent surgical repair (Group A) and 103 were managed entirely with percutaneous image-guided drainage (Group B). There was no significant difference in patient demographics or number of hospital admissions. Patients in Group A had longer median hospital stays compared to Group B (48 vs. 32 days, p = 0.007). The median total hospitalization cost for Group A was more than twice that for Group B ($99,995 vs. $47,838, p = 0.001). Differences in hospital disposition, number of CT examinations, number of drains, and time between original surgery and first CT examination were statistically significant.

CONCLUSION

Gastrointestinal anastomotic leaks managed by percutaneous drainage are associated with lower hospital cost and shorter hospital stays compared with surgical management.

Antimicrobial Susceptibilities of Aerobic and Facultative Gram-Negative Bacilli from Intra-abdominal Infections in Patients from Seven Regions in China in 2012 and 2013

To evaluate the antimicrobial susceptibility of Gram-negative bacilli that caused hospital-acquired and community-acquired intra-abdominal infections (IAIs) in China between 2012 and 2013, we determined the susceptibilities to 12 antimicrobials and the extended-spectrum β-lactamase (ESBL) statuses of 3,540 IAI isolates from seven geographic areas in China in a central laboratory using CLSI broth microdilution and interpretive standards. Most infections were caused by Escherichia coli (46.3%) and Klebsiella pneumoniae (19.7%). Rates of ESBL-producing E. coli (P = 0.031), K. pneumoniae (P = 0.017), and Proteus mirabilis (P = 0.004) were higher in hospital-acquired IAIs than in community-acquired IAIs. Susceptibilities of enterobacteriaceae to ertapenem, amikacin, piperacillin-tazobactam, and imipenem were 71.3% to 100%, 81.3% to 100%, 64.7% to 100%, and 83.1% to 100%, respectively, but imipenem was ineffective against P. mirabilis (<20%). Although most ESBL-positive hospital-acquired isolates were resistant to third- and fourth-generation cephalosporins, the majority were susceptible to cefoxitin (47.9% to 83.9%). Susceptibilities of ESBL-positive isolates to ampicillin-sulbactam (<10%) were low, whereas susceptibilities to ciprofloxacin (0% to 54.6%) and levofloxacin (0% to 63.6%) varied substantially. The prevalences of cephalosporin-susceptible E. coli and K. pneumoniae were higher in the northeastern and southern regions than in the central and eastern regions, reflecting the ESBL-positive rates in these areas, and were lowest in the Jiangsu-Zhejiang (Jiang-Zhe) area where the rates of carbapenem resistance were also highest. Ertapenem, amikacin, piperacillin-tazobactam, and imipenem are the most efficacious antibiotics for treating IAIs in China, especially those caused by E. coli or K. pneumoniae. Resistance to cephalosporins and carbapenems is more common in the Jiang-Zhe area than in other regions in China.

Intra-abdominal Infections

Intra-abdominal infections are multifactorial, but all require prompt identification, diagnosis, and treatment. Resuscitation, early antibiotic administration, and source control are crucial. Antibiotic administration should initially be broad spectrum and target the most likely pathogens. When cultures are available, antibiotics should be narrowed and limited in duration. The method of source control depends on the anatomic site, site accessibility, and the patient's clinical condition. Patient-specific factors (advanced age and chronic medical conditions) as well as disease-specific factors (health care-associated infections and inability to obtain source control) combine to affect patient morbidity and mortality.

Current concept of abdominal sepsis: WSES position paper

Although sepsis is a systemic process, the pathophysiological cascade of events may vary from region to region.

Abdominal sepsis represents the host’s systemic inflammatory response to bacterial peritonitis.

It is associated with significant morbidity and mortality rates, and is the second most common cause of sepsis-related mortality in the intensive care unit.

The review focuses on sepsis in the specific setting of severe peritonitis.

Antioxidant supplementation enhances bacterial peritonitis in mice by inhibiting phagocytosis

Antioxidants are known to exhibit numerous health benefits including anti-ageing, anti-apoptotic and immuno-stimulatory effects. However, we present the data showing counterproductive effects of therapeutically relevant antioxidants on bacterial clearance by the immune system in a murine peritonitic model. The antioxidants ascorbic acid, glutathione and N-acetylcysteine augmented morbidity and mortality in mice carrying Eshcerichia coli-induced acute bacterial peritonitis. Treatment of peritonitic mice with antioxidants significantly increased their bacterial load in the range of 0.3-2 logs. Antioxidant administration to peritonitic mice resulted in decreased numbers of macrophages, B-cells and dendritic cells at the primary site of infection and increased neutrophil infiltration. Serum TNF-α levels were also decreased in antioxidant-treated peritonitic mice. In vitro experiments showed that antioxidants reduced the phagocytic efficacy of peritoneal macrophages by ~60-75% and also decreased E. coli-induced oxidative burst in macrophages cells. Taken together, our data indicate that the antioxidants increased the severity of peritonitis by decreasing the phagocytic efficiency, oxidative burst, and TNF-α production, and increasing neutrophil infiltration. Based on these results, we propose that antioxidant supplementation during the course of bacterial infection is not recommended as it could be detrimental for the host. In addition, the present study underlines the importance of timing and context of antioxidant administration rather than indiscriminate usage to gain the best possible therapeutic advantage of these redox compounds.