Multicenter Study of the Risk Factors and Outcomes of Bloodstream Infections Caused by Carbapenem-Non-Susceptible Acinetobacter baumannii in Indonesia

Mortality and genetic diversity of antibiotic-resistant bacteria associated with bloodstream infections: a systemic review and genomic analysis

BACKGROUND

Bloodstream infections (BSIs) caused by antibiotic-resistant bacteria (ARB) represent a significant disease burden worldwide. However, a comprehensive analysis of the mortality rates and global epidemiology across different ARB species associated with BSIs is currently lacking.

METHODS

We conducted a systematic review by searching multiple databases (PubMed, Web of Science, and Embase) for studies reporting ARB-related BSIs data up to June 19, 2023. Additionally, we performed genomic analyses of all the publicly available bacterial genomes associated with BSIs to elucidate their molecular characteristics.

RESULTS

A total of 322 articles (N = 90,672 patients) were included in this study. For 28 or 30-day mortality, the overall mortality rate for all ARB species was 32.0%. Among them, antibiotic-resistant A. baumannii exhibited the highest rate (54.2%). And the top three ARB types with the highest mortality rates at 28 or 30-day were CefeR-PA (cefepime-resistant P. aeruginosa), CREC (carbapenem-resistant E. coli), and CRAB (carbapenem-resistant A. baumannii), all exceeding 50%, whereas the mortality rates of CRKP (carbapenem-resistant K. pneumoniae), CRPA (carbapenem-resistant P. aeruginosa), and VREfm (vancomycin-resistant E. faecium) were at least 40%. A total of 9,289 ARB genomes related to BSIs were acquired from the NPDIB database and are predominantly distributed in North America, Asia, and Europe. Antibiotic resistance gene (ARG) analysis identified a total of 613 ARG subtypes from the top six ARB species, with numbers ranging from 48 for E. faecium to 253 for K. pneumoniae. Furthermore, specific clones of ARB species were strongly associated with BSIs, such as ST131 in E. coli, ST8, and ST5 in S. aureus, ST2 in A. baumannii, and ST11 and ST258 in K. pneumoniae.

CONCLUSION

ARB contributed to the burden of BSIs, with a 30-day all-cause mortality rate as high as 32.0%. ARB strains causing BSIs display high genetic diversity, highlighting the importance of continuing to monitor high-risk clones to control the development of antibiotic resistance. Differences in ARGs patterns require tailored antibiotic management strategies for each ARB species.

Risk factors for infection after carbapenem-resistant Acinetobacter baumannii colonization

PURPOSE

Predicting infection risk in carbapenem-resistant Acinetobacter baumannii (CRAB) colonized patients may help in improving timely appropriate antibiotic therapy. This study aims to explore risk factors for developing infections in hospitalized patients with previous CRAB colonization.

METHODS

We performed an observational retrospective cohort study at ASST Sette Laghi-Varese Hospital between January 2020 and December 2022. All consecutive adult (> 18 years old) hospitalized patients with documented colonization by CRAB at any anatomical site or with CRAB infections preceded by CRAB colonization were included. Univariate and multivariate analyses were performed to investigate infection risk factors.

RESULTS

Overall, 144 patients were included in the study: 104 colonized only and 40 infected patients. Colonization and infection rates significantly changed over the years (2020-2022, p < 0.001). The incidence of infections in CRAB carriers was 27.8% (40/144). Median time from colonization to infection was 4 days (IQR 1-8.5). Overall, inhospital mortality was 32.7% and 55.0% in colonized only and infected patients, respectively. At the multivariable logistic regression cardiovascular disease (OR 5.83, 95% CI 1.12-30.43, p = 0.037), COVID-19 (OR 3.72, 95% CI 1.16-11.91, p = 0.027) and intensive care unit (ICU) admission (OR 8.83, 95% CI 2.94-26.51, p < 0.001) were risk factors independently associated with cardiovascular disease CRAB infection after colonization.

CONCLUSIONS

We observed an increased infection risk in patients colonized with CRAB with cardiovascular disease, COVID-19 and admitted in ICU setting. Additional evidence is needed to identify predictors of infection in colonized patients.

Analysis of risk factors and different treatments for infections caused by carbapenem-resistant Acinetobacter baumannii in Shaanxi, China

BACKGROUND

The global threat of Carbapenem-resistant Acinetobacter baumannii (CRAB) has intensified as resistance to carbapenems continues to rise in recent decades. We aimed to explore risk factors, molecular epidemiology, and antimicrobial therapy of CRAB infection.

METHODS

The clinical data of 110 patients infected with A. baumannii from December 2021 to December 2022 were retrospectively analyzed. Patients were divided into a carbapenem-resistance group (55 patients) and carbapenem-sensitive group (CSAB; 55 patients) based on resistance to carbapenem, and the risk factors of patients infected with CRAB were analyzed. Fifty-five patients with CRAB infection who received antimicrobial therapy were divided into a combination therapy group (45 patients) and a monotherapy group (10 patients), and differences between the two groups were compared. Whole-genome sequencing analysis was performed to assess resistance genes. Phylogenetic analysis was performed to explore the characteristics of CRAB isolates.

RESULTS

Among the total 110 patients, the rate of poor prognosis in the CRAB group was 43.6% (24/55). Mechanical ventilation (odds ratio [OR] = 5.364, 95% confidence interval [CI] 1.462-19.679, P = 0.011) and puncture (OR = 19.935, 95% CI 1.261-315.031, P = 0.012) were independent risk factors for CRAB infection. Of 55 patients in the antimicrobial regimen study, 45 received combination therapy (including dual, triple, or quadruple antibiotic therapy) and 10 received monotherapy. Univariate analysis revealed significant differences between the combination group and monotherapy group for admission to the intensive care unit and wound infection (P < 0.05). The CRAB strains of 26 patients taking carbapenem-based combination therapy were mainly ST208, ST1968, and ST195, among which patients with ST1968 strains had higher 28-day mortality. Furthermore, the blaOXA-23 gene was harbored in ST1968, ST195, and ST208.

CONCLUSIONS

Mortality was significantly higher in patients infected with CRAB than with CSAB. Mechanical ventilation and puncture were independent risk factors in predicting CRAB infections. The distribution of CRAB was dominated by ST208, ST1968, and ST195, among which patients with ST1968 had higher 28-day mortality. The blaOXA-23 gene appears to be widely disseminated.

Establishment and Validation of a Risk Prediction Model for Mortality in Patients with Acinetobacter baumannii Infection: A Retrospective Study

Purpose

This study aims to establish a valuable risk prediction model for mortality in patients with Acinetobacter baumannii (A. baumannii).

Patients and Methods

The 622 patients with A. baumannii infection from the First Affiliated Hospital of Anhui Medical University were enrolled as the study cohort. Univariate and multivariate logistic regression analysis was used to preliminarily screen the independent risk factors of death caused by A. baumannii infection, followed by LASSO regression analysis to determine the risk factors. According to the calculated regression coefficient, the Nomogram death prediction model is established. The area under the curve (AUC) and decision curve analysis (DCA) of the operating characteristic (ROC) curve of the subjects are used to evaluate the discrimination of the established prediction model. The calibration degree of the prediction model is represented by a calibration chart. A validation cohort that consisted of 477 patients admitted to the 901st Hospital was also included.

Results

Our results revealed that the source of infection, carbapenem-resistant A. baumannii, mechanical ventilation, serum albumin value, and Charlson comorbidity index were independent risk factors for death caused by A. baumannii infection. The AUC value of ROC curves of study cohort and validation cohort were 0.76 and 0.69, respectively. The probability range (30-80%) indicated a high net income of the modified model and strong capacity of discrimination. The calibration curve obtained by analysis swings up and down around the 45 diagonal line, which shows that the calibration degree of the prediction model is very high.

Conclusion

In this study, we have reconstructed a risk prediction model for mortality in patients with A. baumannii infections. This model provides useful information to predict the risk of death in patients with A. baumannii infection, but the specificity is not optimistic. If this prediction model is wanted to be applied to clinical practice, more analysis and research are necessary.

Risk factors for carbapenem-resistant Acinetobacter baumannii (CRAB) bloodstream infections and related mortality in critically ill patients with CRAB colonization

Background

Among MDR bacteria, carbapenem-resistant Acinetobacter baumannii (CRAB) is a major concern due to the limited therapeutic options. During the COVID-19 pandemic, a worrying increase in the spread of CRAB infections was reported.

Objectives

The study assessed the risk factors for CRAB bloodstream infection (BSI) in patients admitted to the ICU with CRAB colonization, and the related mortality risk factors.

Methods

We conducted a single-centre, observational, prospective study; all consecutive patients with CRAB colonization admitted to the ICU of a tertiary hospital in Rome from January 2021 to September 2022 were included in the study. Univariate and multivariate analyses were performed to investigate BSI and mortality risk factors.

Results

Overall, 129 patients were included in the study; 57 (44%) out of these developed BSI. In our study population, at the multivariable analysis the Charlson comorbidity index (CCI) (P = 0.026), COVID-19 (P < 0.001), multisite colonization (P = 0.016) and the need for mechanical ventilation (P = 0.024) were risk factors independently associated with BSI development. Furthermore, age (P = 0.026), CCI (P < 0.001), septic shock (P = 0.001) and Pitt score (P < 0.001) were independently associated with mortality in the BSI patients. Instead, early appropriate therapy (P = 0.002) and clinical improvement within 72 h (P = 0.011) were shown to be protective factors.

Conclusions

In critically ill patients colonized by CRAB, higher CCI, multisite colonization and the need for mechanical ventilation were identified as risk factors for BSI onset. These predictors could be useful to identify patients at highest risk of BSI.