Acinetobacter Baumannii Bloodstream Infections Research Articles

Prognostic Factors That Affect Mortality Patients with Acinetobacter baumannii Bloodstream Infection.

To evaluate the clinical features of patients with Acinetobacter baumannii bloodstream infection (BSI). Totally 200 inpatients with Acinetobacter baumannii BSI were included, clinical features of Acinetobacter baumannii BSI inpatients between 90-day survival and 90-day mortality groups, between 30-day survival and 30-day mortality groups, between patients infected with multidrug-resistant (MDR group) and sensitive Acinetobacter baumannii (sensitive group) were analyzed. The prognostic factors of 90-day mortality were analyzed by univariate logistic regression and multivariate logistic regression. The survival curve in bloodstream infectious patients with multidrug-resistant (MDR group) and sensitive Acinetobacter baumannii (sensitive group) was analyzed by Kaplan-Meier analysis. The 90-day mortality patients had significantly higher carbapenem-resistant bacterial infection and critical care unit (ICU) admission. The 90-day and 30-day mortality groups showed higher C-reactive protein (CRP) and serum creatinine (Scr) levels and lower red blood cells (RBC) and albumin (ALB) levels than their survival counterparts, respectively. Critical surgery, ICU admission and delayed antibiotic treatment were independently prognostic risk predictors for 90-day mortality in Acinetobacter baumannii BSI patients, while critical surgery and diabetes were independently prognostic risk predictors for 90-day mortality in carbapenem-resistant Acinetobacter baumannii BSI patients. Compared with sensitive group, MDR group showed significantly longer ICU and whole hospital stay, lower levels of lymphocytes, RBC, hemoglobin, lactate dehydrogenase and ALB, higher frequency of infection originating from the skin and skin structure. Moreover, patients in the MDR group had a significantly worse overall survival than the sensitive group. We identified the prognostic factors of Acinetobacter baumannii BSI and carbapenem-resistant Acinetobacter baumannii BSI patients. Critical surgery, ICU admission, delayed antibiotic treatment or diabetes were significantly associated with the mortality of those patients. Moreover, aggressive measures to control MDR Acinetobacter baumannii could lead to improved outcomes.

Clinical and microbiological features of a cohort of patients with Acinetobacter baumannii bloodstream infections

PurposeAcinetobacter baumannii is emerging as a pathogen that is a focus of global concern due to the frequent occurrence of the strains those are extensively resistant to antibiotics. This study was aimed to analyze the clinical and microbiological characteristics of a cohort of patients with A. baumannii bloodstream infections (BSIs) in western China.MethodsA retrospective study of the patients at West China Hospital of Sichuan University with A. baumannii BSIs between Jan, 2018 and May, 2023 was conducted. Antimicrobial susceptibility of A. baumannii isolates was tested by microdilution broth method. Whole-genome sequencing and genetic analysis were also performed for these isolates.ResultsAmong the 117 patients included, longer intensive care unit stay, higher mortality, and more frequent invasive procedures and use of more than 3 classes of antibiotics were observed among the carbapenem-resistant A. baumannii (CRAB)-infected group (n = 76), compared to the carbapenem-susceptible A. baumannii (CSAB)-infected group (n = 41, all P ≤ 0.001). Twenty-four sequence types (STs) were determined for the 117 isolates, and 98.7% (75/76) of CRAB were identified as ST2. Compared to non-ST2 isolates, ST2 isolates exhibited higher antibiotic resistance, and carried more resistance and virulence genes (P < 0.05). In addition, 80 (68.4%) isolates were CRISPR-positive, showed higher antibiotic susceptibility, and harbored less resistance and virulence genes, in comparison to CRISPR-negative ones (P < 0.05). Phylogenetic clustering based on coregenome SNPs indicated a sporadic occurrence of clonal transmission.ConclusionOur findings demonstrate a high frequency of ST2 among A. baumannii causing BSIs, and high antibiotic susceptibility of non-ST2 and CRISPR-positive isolates. It is necessary to strengthen the surveillance of this pathogen.

Clinical effectiveness of cefiderocol for the treatment of bloodstream infections due to carbapenem-resistant Acinetobacter baumannii during the COVID-19 era: a single center, observational study.

We assessed the clinical effectiveness of cefiderocol (CFDC) in comparison with colistin (COL) for the treatment of carbapenem-resistant Acinetobacter baumannii (CRAB) bloodstream infections (BSI). Retrospective cohort study including adults with CRAB-BSI. Outcomes were mortality, clinical cure and adverse events during therapy. The average treatment effect of CFDC compared to COL was weighted with the inverse-probability treatment weight (IPTW). Overall, 104 patients were included (50 CFDC, 54 COL), median age 66.5 years, median Charlson Comorbidity Index 5, septic shock in 33.6% of patients. Primary BSI accounted for 43.3% of cases, followed by ventilator-associated pneumonia (VAP) (26%), catheter-related BSI (20.2%) and hospital-acquired pneumonia (HAP) (9.6%). Although not significantly, mortality at all time points was lower for CFDC than COL, while clinical cure was higher in CFDC than COL (66% vs. 44.4%, p = 0.027). Adverse events were more frequent in COL than CFDC-group (38.8% vs. 10%, p < 0.0001), primarily attributed to acute kidney injury (AKI) in the COL group. Patients with bacteremic HAP/VAP treated with CFDC had a significant lower 30-d mortality and higher clinical cure than COL (p = 0.008 and p = 0.0008, respectively). Increment of CCI (p = 0.005), ICU (p = 0.025), SARS-CoV2 (p = 0.006) and ECMO (p < 0.0001) were independently associated with 30-d mortality, while receiving CFDC was not associated with survival. CFDC could represent an effective and safe treatment option for CRAB BSI, especially in patients with bacteremic HAP/VAP and frail patients where the risk of acute renal failure during therapy should be avoided.

Nomogram Based on Clinical Characteristics to Predict 28-Day Mortality Among Patients with CRAB-BSI.

The drug resistance of carbapenem-resistant Acinetobacter baumannii bloodstream infections (CRAB-BSI), especially hospital-acquired infections, has promoted their rapid and vast spread. It is necessary to use reliable methods to establish better prediction models. According to Cox proportional hazards regression, a nomogram was established. A retrospective cohort study among patients who were diagnosed with CRAB-BSI was performed from January 2020 to December 2022. Univariate and multivariate Cox proportional hazards regression analyses were used to determine independent prognostic factors regarding CRAB-BSI. Then, nomograms were used to calculate the area under the curve (AUC), C-index, and calibration curve to determine the predictive accuracy and dis-criminability. Decision curve analysis (DCA) was employed to further confirm the clinical effectiveness of the nomogram. A total of 98 cases were included in the comparison between the 28-day mortality group consisting of 32 patients and the 28-day survival group with 66 patients. The use of cefoperazone-sulbactam was significantly higher among patients who survived than among those who died. Univariable analysis revealed that factors such as primary diagnosis, time to inadequate antimicrobial therapy, and high serum creatinine and procalcitonin (PCT) levels were more prevalent in the mortality group. However, only primary diagnosis, time to inadequate antimicrobial therapy, and high PCT levels emerged as statistically significant risk factors for death in multivariate analysis and were used to construct the nomogram. The nomogram validation exhibited excellent performance. The nomogram was sufficiently accurate to predict the risk and prognostic factors of CRAB-BSI, allowing for individualized clinical decisions for future clinical work. The cefoperazone-sulbactam did have an effect, but more studies are needed to interpret it.

Acinetobacter baumannii Bloodstream Infections: A Nationwide Study in Israel.

Acinetobacter baumannii (Ab) bloodstream infections (BSIs) are a major public health concern and associated with high mortality. We describe the nationwide incidence, antimicrobial resistance, and mortality of Ab-BSI in Israel using laboratory-based BSI surveillance data from January 2018 to December 2019. During the study period, there were 971 Ab-BSI events (508 in 2018 and 463 in 2019), with an average annual incidence of 8.08/100,000 population. The median age of patients was 72 (IQR 62-83), and 56.4% were males. Two-thirds of Ab-BSI events were hospital-onset (HO), with median day of onset 16 (IQR 9-30). HO-BSI incidence was 0.62/10,000 patient-days (rate per 10,000 patient-days: 2.78, 1.17, and 0.2 for intensive care, medical, and surgical wards, respectively). Carbapenem susceptibility was 23.4%; 41.4% and 14.9% in community and HO events, respectively. The 14-day, 30-day, and 1-year mortality were 51.2%, 59.3%, and 81.4%, respectively. Carbapenem-resistant Ab-BSI were associated with a significantly higher 14-day, 30-day, and 1-year mortality (p < 0.001 for all). In the multivariable model, age (aHR 1.02) and carbapenem resistance (aHR 3.21) were independent predictors of 30-day mortality. In conclusion, Ab-BSIs pose a significant burden with high mortality, especially associated with antimicrobial resistance. Attention should be focused on prevention and improving treatment.

Acinetobacter baumannii Bloodstream Infections in the COVID-19 Era: A Comparative Analysis between COVID-19 and Non-COVID-19 Critically Ill Patients.

The coronavirus disease (COVID-19) pandemic increased the incidence of severe infections caused by multidrug-resistant (MDR) pathogens among critically ill patients, such as Acinetobacter baumannii (AB), whose bloodstream infections (BSIs) have been associated with significant mortality. Whether there is any difference in outcome between COVID-19 and non-COVID-19 patients with AB BSI still remains unknown. We conducted a retrospective study comparing clinical characteristics and outcomes of COVID-19 versus non-COVID-19 critically ill patients with AB BSI. Overall, 133 patients with AB BSI (102 COVID-19, 31 non-COVID-19) were studied. The 28-day mortality rate was high and did not differ significantly (69.6% COVID-19 vs. 61.3% non-COVID-19, p = 0.275). Patients with septic shock had a higher mortality rate irrespective of their status with the majority of deaths occurring during the first 7 days. COVID-19 patients were more likely to have ventilator-associated pneumonia (VAP) as the source of BSI (55.8% vs. 22.3%, respectively, p = 0.0001) and were more likely to develop acute respiratory distress syndrome (ARDS) (78.4% vs. 48.4%, respectively, p = 0.001), sepsis (86.3% vs. 67.7%, respectively, p = 0.03), and septic shock (88.3% vs. 58.1%, respectively, p = 0.007) compared to the non-COVID-19 patient group. In conclusion, COVID-19 patients with A. baumannii BSI have a high rate of mortality and more often develop septic shock, while VAP is the main origin of their BSI.

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

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. 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. 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. 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. 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.

Assessment of Effective Antimicrobial Regimens and Mortality-Related Risk Factors for Bloodstream Infections Caused by Carbapenem-Resistant Acinetobacter baumannii.

This study aimed to determine the clinical features, risk factors, and effective antimicrobial therapy for Carbapenem-resistant Acinetobacter baumannii (CRAB) bloodstream infection (BSI). This was a retrospective analysis of data from patients with CRAB bacteremia in a Chinese tertiary hospital between January 2012 and October 2021. Risk factors, predictors of 30-day mortality, and effective antimicrobial therapy for CRAB BSI were identified using logistic and cox regression analyses. Data from 276 patients with Acinetobacter baumannii (AB) BSI were included, of whom 157 (56.9%) had CRAB BSI. The risk factors that were significantly associated with CRAB BSI included previous intensive care unit (ICU) stay (P < 0.001), immunocompromised status (P < 0.001), cephalosporin use (P = 0.014), and fluoroquinolone use (P = 0.007). The 30-day mortality of the CRAB BSI group was 49.7% (78/157). ICU stay after BSI (P = 0.047), sequential organ failure assessment (SOFA) score ≥10 (P < 0.001), and multiple organ failure (MOF) (P = 0.037) were independent predictors of 30-day mortality. Among antibiotic strategies for the treatment of patients with CRAB BSI, we found that definitive regimens containing cefoperazone/sulbactam were superior to those without cefoperazone/sulbactam in reducing the 30-day mortality rate (25.4% vs 53.4%, P = 0.005). After propensity score matching, we observed a significant increase in the 30-day mortality (77.8%vs 33.3%, P = 0.036) in patients receiving tigecycline monotherapy compared to those receiving cefoperazone/sulbactam monotherapy. The mortality rate of patients receiving tigecycline with cefoperazone/sulbactam was also higher than that of patients receiving cefoperazone-sulbactam monotherapy; however, the difference was not significant (28.6%vs 19.0%, P = 0.375). The severity of patient conditions was significantly associated with mortality in patients with CRAB BSI. Those Patients treated with cefoperazone/sulbactam had better clinical prognoses, and tigecycline should be used with caution.

Clinical impact of COVID-19 in patients with carbapenem-resistant Acinetobacter baumannii bacteremia.

The aim of this study was to evaluate the impact of coronavirus disease 2019 (COVID-19) on treatment outcomes in critically ill patients with carbapenem-resistant Acinetobacter baumannii (CRAB) bloodstream infection (BSI). This single-centre, retrospective cohort study was conducted in a 1,048-bed university-affiliated tertiary hospital in the Republic of Korea from January 2021 to March 2022. The study participants included consecutive hospitalised adult patients (aged ≥18years) in the intensive care unit with CRAB monomicrobial BSI. During the study period, a total of 70 patients were included in our study, and 24 (34.3%) were diagnosed with COVID-19. The 28-day mortality rate was 64.3%. In the multivariate Cox proportional hazard regression analysis, diagnosis of COVID-19 (hazard ratio (HR), 2.91; 95% confidence interval (CI): 1.45-5.87), neutropenia (HR, 2.76; 95% CI: 1.04-7.29), Pitt bacteraemia score (per point; HR, 1.30; 95% CI: 1.19-1.41), and appropriate definite antibiotic therapy (HR, 0.31; 95% CI: 0.15-0.62) were independent predictors of 28-day mortality in patients with CRAB BSI. In conclusion, our findings suggested that COVID-19 has a negative prognostic impact on patients with CRAB BSI. Further study is needed to investigate the specific mechanisms of how COVID-19 worsens the prognosis of CRAB infection.

Clinical Characteristics and Prognosis Analysis of Acinetobacter baumannii Bloodstream Infection Based on Propensity Matching.

In view of the fact that Acinetobacter baumannii bloodstream infection(BSI) is a great threat to human survival, early identification of the risk factors affecting prognosis will be of great benefit to the clinic. A propensity score matching method was used to collect patients identified with Acinetobacter baumannii BSI from 2016 to 2020 from a reputable hospital in China. A total of 398 patients were considered. According to the 28-day prognosis, they were divided into the survival group 150 (37.7%) and the death group 248 (62.3%), and the prognosis was analyzed. Subsequently, Propensity score matching was adjusted for variables with p-values <O.2 in the baseline data, equalized differences in baseline, multivariate paired logistics regression analysis was performed on 63 matched patients and showed that patients with Acinetobacter baumannii BSI who had higher SOFA scores at the time of infection, with septic shock, or mechanical ventilation were more likely to be fatally hit within 28 days and had a poor prognosis. The existence of drug resistance with Acinetobacter baumannii only leads to Inappropriate empirical antibiotic therapy, ultimately, Inappropriate empirical antibiotic therapy was the direct predictor of mortality.

Multidrug-Resistant Acinetobacter baumannii May Cause Patients to Develop Polymicrobial Bloodstream Infection.

Background The incidence of polymicrobial bloodstream infections is increasing, the clinical characteristics of polymicrobial Acinetobacter baumannii bloodstream infections (AB-BSI) are unclear, and there are no reports of polymicrobial AB-BSI in mainland China. Therefore, our objective was to identify the clinical characteristics, risk factors, and outcomes of polymicrobial AB-BSI versus monomicrobial AB-BSI. Methods A retrospective survey of all patients with AB-BSI from January 1, 2015, to December 31, 2019, and their clinical data were collected and analyzed by reviewing electronic medical records. All data were compared and analyzed between groups of monomicrobial and polymicrobial AB-BSI. Risk factors for polymicrobial AB-BSI were assessed using multivariable logistic regression analysis. Results A total of 204 patients were included, of which 39 (19.1%) were patients with polymicrobial AB-BSI. The main sources of the pathogenicity of polymicrobial Acinetobacter baumannii bloodstream infections were skin and soft tissue (38.5% vs. 16.4%, p=0.002). Resistance to piperacillin/tazobactam as an independent factor for polymicrobial AB-BSI was found in multivariate analysis. Patients with polymicrobial AB-BSI had longer hospital stays compared to those with monomicrobial AB-BSI. However, there was no significant difference in mortality between the two groups. Conclusions Polymicrobial AB-BSI accounted for a significant proportion among all AB-BSI, and it did not influence mortality but was related to slightly longer total hospital stays. Multidrug resistance was associated with the development of polymicrobial AB-BSI but does not directly lead to polymicrobial AB-BSI, whereas resistance to piperacillin/tazobactam was highly correlated with polymicrobial AB-BSI. Therefore, while treating A. baumannii bloodstream infections, clinicians cannot ignore the multidrug-resistant A. baumannii, especially piperacillin/tazobactam-resistant A. baumannii, which may predispose to the development of polymicrobial AB-BSI.

Risk Factors for and Clinical Outcomes of Polymicrobial Acinetobacter baumannii Bloodstream Infections.

Background Although the clinical features of Acinetobacter baumannii bloodstream infection are well described, the specific clinical characteristics of polymicrobial Acinetobacter baumannii bloodstream infection have been rarely reported. The objective of this study was to examine the risk factors for and clinical outcomes of polymicrobial Acinetobacter baumannii bloodstream infection. Methods A retrospective observational study was performed from January 2013 to December 2018 in a tertiary hospital. All patients with Acinetobacter baumannii bloodstream infection were enrolled, and the data were collected from the electronic medical records. Results A total of 594 patients were included, 21% (126/594) of whom had polymicrobial infection. The most common copathogen was Klebsiella pneumoniae (20.81%), followed by Pseudomonas aeruginosa (16.78%) and Enterococcus faecium (12.08%). Compared with monomicrobial Acinetobacter baumannii bloodstream infection, polymicrobial Acinetobacter baumannii bloodstream infection mostly originated from the skin and soft tissue (28.6% vs. 10.5%, p < 0.001). Multivariate analysis revealed that burn injury was independently associated with polymicrobial Acinetobacter baumannii bloodstream infection (adjusted odds ratio, 3.569; 95% confidence interval, 1.954-6.516). Patients with polymicrobial Acinetobacter baumannii bloodstream infection were more likely to have a longer hospital length of stay [40 (21, 68) vs. 27 (16, 45), p < 0.001] and more hospitalization days after bloodstream infection than those with monomicrobial Acinetobacter baumannii bloodstream infection [22 (8, 50) vs. 13 (4, 28), p < 0.001]. However, no significant difference in mortality was observed between the two groups. Conclusions Approximately one-fifth of Acinetobacter baumannii bloodstream infections were polymicrobial in this cohort. The main sources were skin and soft tissue infections, and burn injury was the only independent risk factor. Although mortality did not differ between the groups, considering the limitations of the study, further studies are required to assess the impact of polymicrobial (vs. monomicrobial) Acinetobacter baumannii bloodstream infection on outcomes.

A descriptive case series of pharmacokinetic/pharmacodynamic target attainment and microbiological outcome in critically ill patients with documented severe extensively drug-resistant Acinetobacter baumannii bloodstream infection and/or ventilator-associated pneumonia treated with cefiderocol

The aim of this study was to explore the relationship between cefiderocol pharmacokinetic/pharmacodynamic (PK/PD) target attainment and microbiological outcome in critically ill patients affected by extensively drug-resistant Acinetobacter baumannii (XDR-AB) bloodstream infection (BSI) and/or ventilator-associated pneumonia (VAP). Patients who received compassionate use of cefiderocol to treat documented XDR-AB infections at the intensive care unit of the IRCCS Azienda Ospedaliero-Universitaria of Bologna and who underwent therapeutic drug monitoring (TDM) from 15 March 2021 to 30 April 2021 were retrospectively assessed. Cefiderocol trough concentration (Cmin) was determined at steady-state, and the free fraction (fCmin) was calculated according to a plasma protein binding of 58%. The fCmin/MIC ratio was selected as a pharmacodynamic parameter of cefiderocol efficacy and was defined as optimal if ≥4, quasi-optimal if between 1 and 4, and suboptimal if <1. The association between fCmin/MIC and microbiological outcome was assessed. A total of 13 patients treated with cefiderocol for the management of XDR-AB infections (6 BSI plus VAP, 5 VAP and 2 BSI) were retrieved. fCmin/MIC ratios were suboptimal in 3 cases (23%) and quasi-optimal or optimal in 5 cases each (38%). Microbiological failure occurred in seven cases (54%; six with VAP and one with VAP plus BSI). Microbiological failure occurred in 80% of patients with suboptimal fCmin/MIC compared with 29% of those achieving optimal or quasi-optimal fCmin/MIC ratio. Suboptimal attainment of PK/PD targets of cefiderocol may lead to microbiological failure of treatment with cefiderocol of critically ill patients affected by XDR-AB VAP.

Meta-analysis of Risk Factors for Mortality in Patients with Acinetobacter Baumannii Bloodstream Infection

Background: Patients with Acinetobacter baumannii bloodstream infection (ABBI) have a poor prognosis and high mortality. Early identification of risk factors for death in patients with ABBI, and appropriate prevention and control measures are extremely important to reduce the mortality. Objective: To systematically evaluate the risk factors of ABBI, which provide evidence for reducing the incidence and mortality of patients. Methods: The published articles and reference works on prognosis risk factors in patients with ABBI were retrieved from inception to January 2021 in the following databases: PubMed, Web of Science, Embase, CNKI, Wanfang and VIP. Those studies that met the inclusion criteria were perform quality evaluation and data analysis. Meta-analysis was performed by the statistical software Stata13.0. Results: A total of 24 articles were included, including 1 203 patients in the death group and 1 319 patients in the survival group. Among the 24 included study factors, 15 showed statistically significant differences(P<0.01), including: age (MD=0.19, 95%CI: 0.08~0.30, P<0.01), APACHE II (MD=0.48, 95%CI: 0.06~0.91, P=0.03), ICU admission (OR=1.91, 95%CI: 1.12~3.26, P=0.02), shock (OR=4.28, 95% CI: 1.05~17.49, P=0.04), septic shock (OR=8.36, 95%CI: 3.71~18.82, P<0.01), renal damage (OR=1.57, 95%CI: 1.19~2.07, P<0.01), diabetes (OR=1.31,95%CI: 1.03~1.68, P=0.03), malignant tumor (OR=1.56, 95%CI: 1.02~2.37, P=0.04 ), liver disease (OR=1.93, 95%CI: 1.25~3.00, P<0.01), hormonal used (OR=5.46, 95%CI: 3.12~9.56, P<0.01), immunosuppression (OR=2.73, 95%CI: 1.82~4.1, P<0.01 ), mechanical ventilation (OR=3.17, 95%CI: 2.34~4.29, P<0.01), deep vein catheterization (OR=2.02, 95%CI: 1.56~2.61, P<0.01), indwelling urinary catheter (OR =2.53, 95%CI: 1.66~3.84, P<0.01), indwelling gastric tube (OR=1.79, 95%CI: 1.21~2.65, P<0.01). Conclusion: The severity of the patient's underlying disease, using of hormones and immunosuppressants, and various invasive operations were the main risk factors for high mortality in ABBI patients. It was necessary to focus on older patients, dynamically monitor the APACHE II score, carefully evaluate the effect of hormone and immunosuppressant application, and strictly control the indications of invasive operation or treatment.

Counter Clinical Prognoses of Patients With Bloodstream Infections Between Causative Acinetobacter baumannii Clones ST191 and ST451 Belonging to the International Clonal Lineage II

This study was conducted to evaluate the possible clinical and bacteriologic features associated with 30-day mortality from Acinetobacter baumannii (A. baumannii) bloodstream infections (BSIs). We conducted a prospective, multicenter, observational study of 181 entire episodes of A. baumannii BSI from six general hospitals between May 2016 and April 2017 in South Korea. Cox proportional-hazards regression model was used to estimate risks of the primary endpoint, i.e., all-cause mortality within 30 days from the initial blood culture. Most (84.5%) of the A. baumannii blood isolates belonged to the international clonal lineage II (ICLII) and 89.5% of the isolates were either multidrug- or extensively-drug resistant. We identified three risk factors including the old age of patient {hazard ratio, 1.033; [95% Confidential Interval (CI), 1.010–1.056]}, the sequential organ failure assessment score [1.133 (1.041–1.233)], and causative A. baumannii sequence type (ST) 191 belonging to ICLII [1.918 (1.073–3.430)], and three protective factors including causative A. baumannii ST451 belonging to ICLII [0.228 (0.078–0.672)], platelet count [0.996 (0.993–0.999)], and definitive therapy within 72 h [0.255 (0.125–0.519)]. Differing 30-day mortality rate in the dominant ICLII was observed by ST, which was much high in ST191 and low in ST451 and it was likely associated with the molecular traits, rather than the drug resistance.

Comparison of Tigecycline or Cefoperazone/Sulbactam therapy for bloodstream infection due to Carbapenem-resistant Acinetobacter baumannii

BackgroundWe retrospectively analyzed the effect of tigecycline and cefoperazone/sulbactam therapies on the prognosis of patients with carbapenem-resistant Acinetobacter baumannii bloodstream infection (CRAB-BSI).MethodsCRAB-BSI patients receiving tigecycline therapy or cefoperazone/sulbactam therapy between January 2012 and December 2017 was enrolled, and strict exclusion criteria were followed. The 28-day mortality of patients was analyzed. The impact of cefoperazone/sulbactam therapy on prognosis was evaluated using Cox multivariate regression analysis. The 28-day mortality of patients receiving cefoperazone/sulbactam monotherapy and cefoperazone/sulbactam-based combination therapy was also compared.ResultsThree hundred forty eight patients with CRAB-BSI were enrolled in the study. Two hundred ten patients were included after applying the exclusion criteria. Of these, 135 patients received tigecycline therapy and 75 patients received cefoperazone/sulbactam therapy. The 28-day mortality of patients in the latter group was, significantly lower than that of the tigecycline group [29.3% vs. 51.9%; P = 0.001]. Cox multivariate regression analysis revealed that cefoperazone/sulbactam therapy exerted a protective effect on the prognosis of patients [hazard ratio 0.566, 95% confidence interval (0.342–0.940); P = 0.028]. Kaplan-Meier survival curve analysis indicated that the 28-day mortality of patients receiving cefoperazone/sulbactam therapy was lower than that of patients receiving cefoperazone/sulbactam monotherapy, but the difference was not significant (22.2% vs. 40%; P = 0.074). However, the mortality of patients receiving cefoperazone/sulbactam with imipenem/cilastatin was significantly lower than that of patients receiving cefoperazone/sulbactam monotherapy (P = 0.048).ConclusionsPatients treated with cefoperazone/sulbactam therapy had a better clinical outcome. The mortality of patients receiving cefoperazone/sulbactam with imipenem/cilastatin seems to be the lowest.

Exploring a phage-based real-time PCR assay for diagnosing Acinetobacter baumannii bloodstream infections with high sensitivity

In the present study, we developed a phage-based real-time quantitative PCR (qPCR) methodology for sensitive diagnosis of bloodstream infection (BSI) caused by Acinetobacter baumannii (A. baumannii). An isolated A. baumannii phage p53 was used for Taqman qPCR through detecting phage replication in live A. baumannii cells in serum samples. At the phage concentration of 103 PFU/mL, the sensitive detection of A. baumannii (down to 10 CFU in 100 μL serum) has been obtained within 4 h in spiked serum samples without bacteria isolation and DNA extraction. Subsequent testing of 22 simulated serum samples spiked by different strains has shown that the results from the phage-based Taqman qPCR method have 100% agreement with the spiked concentrations of the bacteria. The assay built in this study, gathering all the advantages for detections of high rapidity, high sensitivity, good specificity, being able to detect only live bacteria not dead bacteria and no DNA extraction or purifications, can be developed to detecting other bacterial pathogens in serum or other complicated samples through switching to other types of phages and realize the rapid and sensitive detection of bacteria in BSI, which would potentially be applied for fast diagnosis in sepsis clinically.

Analysis of clinical manifestations and risk factors of mortality in Acinetobacter baumannii bloodstream infection

To explore the clinical manifestations, antimicrobial therapy, and risk factors of mortality in patients with Acinetobacter baumannii bloodstream infection. Clinical data of 153 patients with Acinetobacter baumannii bloodstream infection hospitalized in First Affiliated Hospital of Zhejiang University from January 2013 to September 2014 were analyzed retrospectively.According to the 28-day survival after diagnosis, the patients were divided into death group (n=76) and survival group (n=77). Data related to demographic and clinical characteristics, underlying diseases, treatment, invasive procedures, bacterial resistance to antibiotics, acute physiology and chronic health evaluation Ⅱ(APACHEⅡ )scores at onset, and antimicrobial therapy were collected.The index as an independent risk factor of mortality was demonstrated by multivariate logistic regression analysis. This study included 153 patients with Acinetobacter baumannii bloodstream infection. The 28-day mortality was 49.7%. The independent risk factors of mortality were APACHE Ⅱ score ≥ 22 at onset (OR=15.7, 95%CI 5.1-48.1, P<0.001), septic shock(OR=6.3, 95%CI 1.9-21.3, P=0.003), and administration of steroids(OR=3.6, 95%CI 1.0-12.3, P=0.043). Compared with subjects treated with non-cefoperazone-sulbactam-based regimen , those treated with cefoperazone-sulbactam for multidrug-resistant Acinetobacter baumannii(MDR-AB) had significantly lower mortality on day7, day14 and day28(8.9% vs 59.2%, 31.1% vs 65.8%, 44.4% vs 72.4% respectively). The patients with Acinetobacter baumannii bloodstream infection have high mortality within one month. Administration of steroids and septic shock are associated with poor prognosis. APACHEⅡ score ≥ 22 at onset predicts adverse outcome. Cefoperazone-sulbactam-based antimicrobial therapy improves patients' survival.

Analysis of risk factors on prognosis of Acinetobacter baumannii bloodstream infection

Objective To explore the risk factors on prognosis of Acinetobacter baumannii bloodstream infection.Methods Clinical data from 78 patients with Acinetobacter baumannii bloodstream infection hospitalized in First Affiliated Hospital of Nanjing Medical University from January 2010 to November 2012 were analyzed retrospectively.According to the 28-day prognosis after admission,the patients were divided into non-survivors (n=40) and survivors (n=38).Data on demographic and clinical characteristics,wards,underlying diseases,treatments,invasive medical procedures,bacterial resistance to antibiotics,and acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score in the beginning were collected.The index as an independent risk factor of mortality was demonstrated by multivariate logistic regression analysis.The predictor value was concluded by comparing area under the receiver operating characteristic curve (ROC curve) of each index.Results Risk factors of mortality of Acinetobacter baumannii bloodstream infection goes as following,including intensive care unit admission [ICU,odds ratio (OR)=12.9,95％ confidence interval (95％ CI) 2.4-63.5,P=0.001],trachea intubationor tracheostomy (OR =6.2,95％ CI 1.5-30.4,P=0.023),invasive mechanical ventilation (OR =5.1,95％ CI 1.4-22.6,P=0.042),invasive medical procedure besides central venous catheter (including thoracentesis,bone marrow puncture,lumbar puncture,catheterization,bronchoalveolar lavage with bronchofibroscope,arteriovenous fistula plastic operation,OR =8.4,95％CI 1.7-37.8,P=0.011),APACHE Ⅱ score ≥ 19 in the beginning (OR=35.4,95％CI 3.8-318.6,P=0.001).With respect to APACHE Ⅱ score ≥ 19 as mortality cut-off point,an area under the receiver operating curve of 0.938 was statistically significant (P＜0.05),with sensitivity 76.2％ and specificity 94.1％.The relationship between prognosis and antibiotic resistance did not have statistically significance.Conclusion Invasive medical procedures and treatments were associated with increased mortality of patients with Acinetobacter baumannii bloodstream infection.A strong predictor of adverse outcome in such conditions was APACHE Ⅱ score ≥ 19. Key words: Acinetobacter baumannii; Bloodstream infection; Risk factor; Acute physiology and chronic health evaluation Ⅱ

Ecological competition and the incidence of Acinetobacter baumannii bloodstream infections in a teaching hospital in Southeastern Brazil.

Recently, pathogen ecology has been recognized as an important epidemiological determinant of healthcare-associated infections (HAIs). Acinetobacter baumannii is one of the most important agents known to cause HAIs. It is widespread in healthcare settings and exhibits seasonal variations in incidence. Little is known about the impact of competition with other hospital pathogens on the incidence of A. baumannii infection. We conducted an ecological study, enrolling patients who presented with healthcare-associated bloodstream infections (HA-BSIs) from 2005 to 2010 at a 450-bed teaching hospital in Brazil. HA-BSIs were said to be present when bacteria or fungi were recovered from blood cultures collected at least three days after admission. Monthly incidence rates were calculated for all HA-BSIs (overall or caused by specific pathogens or groups of pathogens). Multivariate Poisson regression models were used to identify the impacts of the incidence of several pathogens on the incidence of A. baumannii. The overall incidence rate of HA-BSI caused by A. baumannii was 2.5 per 10,000 patient-days. In the multivariate analysis, the incidence of HA-BSI caused by A. baumannii was negatively associated with the incidence rates of HA-BSI due to Staphylococcus aureus (rate ratio [RR]=0.88; 95% confidence interval [CI]=0.80-0.97), Enterobacter spp. (RR=0.84; 95%CI=0.74-0.94) and a pool of less common gram-negative pathogens. Our results suggest that competition between pathogens influences the etiology of HA-BSIs. It would be beneficial to take these findings into account in infection control policies.