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

Epidemiology and risk factors for mortality in critically ill patients with pancreatic infection

Background

The AbSeS-classification defines specific phenotypes of patients with intra-abdominal infection based on the (1) setting of infection onset (community-acquired, early onset, or late-onset hospital-acquired), (2) presence or absence of either localized or diffuse peritonitis, and (3) severity of disease expression (infection, sepsis, or septic shock). This classification system demonstrated reliable risk stratification in intensive care unit (ICU) patients with intra-abdominal infection. This study aimed to describe the epidemiology of ICU patients with pancreatic infection and assess the relationship between the components of the AbSeS-classification and mortality.

Methods

This was a secondary analysis of an international observational study ("AbSeS") investigating ICU patients with intra-abdominal infection. Only patients with pancreatic infection were included in this analysis (n=165). Mortality was defined as ICU mortality within 28 days of observation for patients discharged earlier from the ICU. Relationships with mortality were assessed using logistic regression analysis and reported as odds ratio (OR) and 95% confidence interval (CI).

Results

The overall mortality was 35.2% (n=58). The independent risk factors for mortality included older age (OR=1.03, 95% CI: 1.0 to 1.1 P=0.023), localized peritonitis (OR=4.4, 95% CI: 1.4 to 13.9 P=0.011), and persistent signs of inflammation at day 7 (OR=9.5, 95% CI: 3.8 to 23.9, P<0.001) or after the implementation of additional source control interventions within the first week (OR=4.0, 95% CI: 1.3 to 12.2, P=0.013). Gram-negative bacteria were most frequently isolated (n=58, 49.2%) without clinically relevant differences in microbial etiology between survivors and non-survivors.

Conclusions

In pancreatic infection, a challenging source/damage control and ongoing pancreatic inflammation appear to be the strongest contributors to an unfavorable short-term outcome. In this limited series, essentials of the AbSeS-classification, such as the setting of infection onset, diffuse peritonitis, and severity of disease expression, were not associated with an increased mortality risk.ClinicalTrials.gov number: NCT03270345.

The roles of tissue-resident macrophages in sepsis-associated organ dysfunction

Sepsis, a syndrome caused by a dysregulated host response to infection and characterized by life-threatening organ dysfunction, particularly septic shock and sepsis-associated organ dysfunction (SAOD), is a medical emergency associated with high morbidity, high mortality, and long-term sequelae. Tissue-resident macrophages (TRMs) are a subpopulation of macrophages derived primarily from yolk sac progenitors and fetal liver during embryogenesis, located primarily in non-lymphoid tissues in adulthood, capable of local self-renewal independent of hematopoiesis, and developmentally and functionally restricted to the non-lymphoid organs in which they reside. TRMs are the first line of defense against life-threatening conditions such as sepsis, tumor growth, traumatic-associated organ injury, and surgical-associated injury. In the context of sepsis, TRMs can be considered as angels or demons involved in organ injury. Our proposal is that sepsis, septic shock, and SAOD can be attenuated by modulating TRMs in different organs. This review summarizes the pathophysiological mechanisms of TRMs in different organs or tissues involved in the development and progression of sepsis.

Critical appraisal beyond clinical guidelines for intraabdominal candidiasis

BACKGROUND

Regardless of the available antifungals, intraabdominal candidiasis (IAC) mortality continues to be high and represents a challenge for clinicians.

MAIN BODY

This opinion paper discusses alternative antifungal options for treating IAC. This clinical entity should be addressed separately from candidemia due to the peculiarity of the required penetration of antifungals into the peritoneal cavity. Intraabdominal concentrations may be further restricted in critically ill patients where pathophysiological facts alter normal drug distribution. Echinocandins are recommended as first-line treatment in guidelines for invasive candidiasis. However, considering published data, our pharmacodynamic analysis suggests the required increase of doses, postulated by some authors, to attain adequate pharmacokinetic (PK) levels in peritoneal fluid. Given the limited evidence in the literature on PK/PD-based treatments of IAC, an algorithm is proposed to guide antifungal treatment. Liposomal amphotericin B is advocated as first-line therapy in patients with sepsis/septic shock presenting candidemia or endophthalmitis, or with prior exposure to echinocandins and/or fluconazole, or with infections by Candida glabrata. Other situations and alternatives, such as new compounds or combination therapy, are also analysed.

CONCLUSION

There is a critical need for more robust clinical trials, studies examining patient heterogeneity and surveillance of antifungal resistance to enhance patient care and optimise treatment outcomes. Such evidence will help refine the existing guidelines and contribute to a more personalised and effective approach to treating this serious medical condition. Meanwhile, it is suggested to broaden the consideration of other options, such as liposomal amphotericin B, as first-line treatment until the results of the fungogram are available and antifungal stewardship could be implemented to prevent the development of resistance.

Impact of secondary sepsis on mortality in adult intensive care unit patients

RATIONALE

Septic patients admitted to the intensive care unit (ICU) suffer from immune dysregulation, potentially leading to a secondary sepsis episode. This study aims to (i) assess the secondary sepsis rate, (ii) compare the second with the first episodes in terms of demographics, clinical and laboratory characteristics, and outcomes, and iii) evaluate the outcome of secondary sepsis.

METHODS

A single-center, retrospective study (2014-2017) was conducted in a Greek ICU, including consecutive cases of adult patients admitted to the ICU for at least 48 h with a principal admission diagnosis of sepsis and stayed for at least 48 h. We searched for a secondary episode of sepsis following the primary-one. We performed survival analyses with Cox proportional hazard, Fine-Gray, and multistate models.

RESULTS

In this study, 121 patients that fulfilled the eligibility criteria were included. The secondary sepsis group included 28 (23.1 %) patients, with episode onset, median (interquartile range), 9.5 (7.7-16.2) days after ICU admission, who had less frequently had a medical admission diagnosis, a microbiologically confirmed first episode, and the C-reactive protein was lower. The overall ICU mortality of the cohort was 44.6 %. The group that developed secondary sepsis had higher mortality, but significance was lost in Cox regression [Hazard ratio (95 % CI) 0.59(0.31-1.16)]. However, after multistate modeling adjustment, the attributable mortality was estimated at 43.9 % (95 %CI ± 14.8 %).

CONCLUSION

Secondary sepsis was evident in a quarter of the study participants and may be associated with an increased risk of death.

Outcomes of Beta-Lactam Allergic and Non-Beta-Lactam Allergic Patients with Intra-Abdominal Infection: A Case-Control Study

Background: In the case of intra-abdominal infections (IAI) in beta-lactam (BL) allergic patients, empiric antimicrobial therapy without BL is recommended; however, data regarding the outcome with alternative regimens are scarce. This study aimed to compare the outcomes of BL allergic (BLA) patients with IAI to those who were non-BLA (NBLA). Method: We conducted a case−control study in a French teaching hospital, between 1 January 2016 and 31 August 2021. BLA patients with IAI treated with fluoroquinolone or aztreonam and metronidazole were matched with controls treated with BL, on age, sex, disease severity, IAI localization, and healthcare-associated infection (HAI) status. We compared rates of therapeutic failures, adverse events, and HAI, and then assessed factors associated with therapeutic failure using a logistic regression model. Results: The therapeutic failure rate was 14% (p > 0.99) in both groups of 43 patients, and there was no significant difference in the adverse events rate (p > 0.99) and HAI rate (p = 0.154). Factors independently associated with therapeutic failure were higher BMI (OR 1.16; 95%CI [1.00−1.36]; p = 0.041), longer hospital length of stay (OR 1,20; 95%CI [1.08−1.41]; p = 0.006), and inadequate empiric antimicrobial therapy (OR 11.71; 95%CI [1.43−132.46]; p = 0.025). Conclusion: The outcomes of BLA patients with IAI treated without BL were the same as those for NBLA patients treated with BL.

Poor timing and failure of source control are risk factors for mortality in critically ill patients with secondary peritonitis

PURPOSE

To describe data on epidemiology, microbiology, clinical characteristics and outcome of adult patients admitted in the intensive care unit (ICU) with secondary peritonitis, with special emphasis on antimicrobial therapy and source control.

METHODS

Post hoc analysis of a multicenter observational study (Abdominal Sepsis Study, AbSeS) including 2621 adult ICU patients with intra-abdominal infection in 306 ICUs from 42 countries. Time-till-source control intervention was calculated as from time of diagnosis and classified into 'emergency' (< 2 h), 'urgent' (2-6 h), and 'delayed' (> 6 h). Relationships were assessed by logistic regression analysis and reported as odds ratios (OR) and 95% confidence interval (CI).

RESULTS

The cohort included 1077 cases of microbiologically confirmed secondary peritonitis. Mortality was 29.7%. The rate of appropriate empiric therapy showed no difference between survivors and non-survivors (66.4% vs. 61.3%, p = 0.1). A stepwise increase in mortality was observed with increasing Sequential Organ Failure Assessment (SOFA) scores (19.6% for a value ≤ 4-55.4% for a value > 12, p < 0.001). The highest odds of death were associated with septic shock (OR 3.08 [1.42-7.00]), late-onset hospital-acquired peritonitis (OR 1.71 [1.16-2.52]) and failed source control evidenced by persistent inflammation at day 7 (OR 5.71 [3.99-8.18]). Compared with 'emergency' source control intervention (< 2 h of diagnosis), 'urgent' source control was the only modifiable covariate associated with lower odds of mortality (OR 0.50 [0.34-0.73]).

CONCLUSION

'Urgent' and successful source control was associated with improved odds of survival. Appropriateness of empirical antimicrobial treatment did not significantly affect survival suggesting that source control is more determinative for outcome.

Epidemiology and Age-Related Mortality in Critically Ill Patients With Intra-Abdominal Infection or Sepsis: An International Cohort Study

BACKGROUND

The objective of this study is to describe the epidemiology and age-related mortality in older critically ill adults with intra-abdominal infections.

METHODS

This is a secondary analysis of a prospective, multinational, observational study (AbSeS, ClinicalTrials.gov #NCT03270345) including patients with intra-abdominal infection from 309 ICUs in 42 countries (January-December, 2016). Mortality was considered as ICU mortality with a minimum of 28 days of observation when patients were discharged earlier. Relationships with mortality were assessed by logistic regression analysis.

RESULTS

The cohort included 2337 patients. Four age groups were defined: middle-aged patients as reference category (40-59 years; n=659 [28.2%]), young-old (60-69 years; n=622 [26.6%]), middle-old (70-79 years; n=667 [28.5%]) and very-old patients (≥80 years; n=389 [16.6%]). Secondary peritonitis was the predominant infection (68.7%) and equally prevalent across age groups. Mortality increased with age: 20.9% in middle-aged patients, 30.5% in young-old, 31.2% in middle-old, and 44.7% in very-old patients (p<0.001). Compared to middle-aged patients, young-old age (OR 1.62, 95% CI 1.21-2.17), middle-old age (OR 1.80, 95% CI 1.35-2.41), and very-old age (OR 3.69, 95% CI 2.66-5.12) were independently associated with mortality. Other independent risk factors for mortality included late-onset hospital-acquired intra-abdominal infection, diffuse peritonitis, sepsis/septic shock, source control failure, liver disease, congestive heart failure, diabetes, and malnutrition.

CONCLUSIONS

For ICU patients with intra-abdominal infections, age above 60 years was associated with mortality while patients above 80 years had the worst prognosis. Comorbidities and overall disease severity further compromised survival. As all these factors are non-modifiable it remains unclear how to improve outcomes.