Predictors of mortality of Acinetobacter baumannii infections: A 2-year prospective study in a Greek surgical intensive care unit

BACKGROUND

Nosocomial infections are a frequent and continuously increasing problem worldwide, have a rapidly increasing multidrug resistance to antibiotics, and are associated with significant morbidity and mortality.

OBJECTIVE

Our objectives were to evaluate Acinetobacter baumannii infection incidence in our surgical intensive care unit (SICU), the clinical features and outcome of these patients, and, particularly, to investigate predictors of A baumannii infection-related mortality.

METHODS

Ours was a prospective study of all patients with ICU-acquired A baumannii infection from January 1, 2006, to December 31, 2007.

RESULTS

Among 680 patients, 60 (8.8%) sustained A baumannii infection. Mean age was 68.4 ± 6.2 years, Acute Physiology and Chronic Health Evaluation (APACHE) II score on SICU admission 20.6 ± 8.1 and Sequential Organ Failure Assessment (SOFA) score on infection day 9.5 ± 4.2 (women: 50%). Multidrug resistance, morbidity, and mortality were 45%, 65%, and 46.6% (n = 28), respectively. In multivariate analysis, age (P = .03; odds ratio [OR], 1.13; 95% confidence interval [CI]: 1.018-1.259), acute renal failure (P = .001; OR, 17.9; 95% CI: 6.628-75.565), and thrombocytopenia (P = .03; OR, 26.4; 95% CI: 1.234-56.926) complicating the infection and subsequent Enterococcus faecium bacteremia (P = .01; OR, 3.5; 95% CI: 1.84-6.95) were mortality predictors.

CONCLUSION

A baumannii infections are frequent and associated with high drug multiresistance, morbidity, and mortality. Age, renal failure, thrombocytopenia, and subsequent E faecium bacteremia were predictors of A baumannii infection-associated mortality.

Mortality rate in patients with nosocomial Acinetobacter meningitis from a Brazilian hospital

BACKGROUND

The mortality rate due to Acinetobacter baumannii nosocomial meningitis (ANM) is high.

OBJECTIVE

The aim of this study was to evaluate the factors that have influence over the outcomes in ANM patients.

METHODS

A retrospective analysis of 22 cases of ANM was conducted in a hospital with high incidence of multidrug resistance.

RESULTS

The mean age of patients was 43 years (21 to 91) and 54.5% were male. All ANM cases occurred within 60 days of admission and the mean duration of illness was of 18.2 days. All cases were associated with previous neurosurgical procedures: elective surgery (27.2%), external shunt (54.4%) and emergency surgery due to trauma (18.1%). Imipenem resistance was observed in 40.9% of cases, but ampicillin/sulbactam resistance was lower (27.2%). The mortality rate of ANM patients was of 72.7%. The only risk factor associated with mortality was inappropriate therapy within five days after CSF collection. All patients who survived the meningitis episode had received appropriate therapy, in contrast to only 69.2% of those who did not survive (OR = 5.15; IC = 0.45-54.01).

CONCLUSIONS

The high mortality rate observed in our study suggests the need for aggressive empirical treatment with addition of drugs, including intrathecal therapy, where multi-resistant A. baumannii is endemic.

[Multidrug resistant Acinetobacter baumanii:clinical update and new highlights]

The role of multidrug resistant Acinetobacter baumanii and its clinical relevance have been recently appreciated as a ubiquitous opportunistic nosocomial pathogen. Risk factors associated with A. baumanii infection include severe underlying diseases, previous surgery, invasive procedures, treatment with broad-spectrum antibiotics, length of hospital stay, admission to intensive care units (ICU). Carbapenem-multidrug resistant A. baumanii infections are probably associated to greater severity and more complications; in our cohort mortality was 49.3% and related mortality (within 72 hours) was 10.39%. However, severe underlying diseases probably play an important role in the clinical outcome of patients with MDR-C A. baumanii infection and controversy exists regarding the real mortality attributable to antimicrobial resistance because a high proportion of deaths took place > 7 days after diagnosis. Nevertheless, in our experience, carbapenem resistance, inappropriate therapy and monotherapy are associated to a higher mortality. Special attention should be paid to design well-controlled prospective clinical trials to determine the optimal antimicrobial therapy in critically ill patients suspected of having MDR Acinetobacter infection.

[Risk of hospital death in nosocomial infection with multi-drug resistant A. baumanii or P. aeruginosa]

OBJECTIVE

assessment of the in hospital death among the patients with healthcare associated infection (HA1) provoked by multi drug resistant strains (MDR) ofP. aeruginosa or A. baumanii.

METHODS

enrolled in the study were patients with bloodstream, surgical site and urinary tract HAI infection, reported during 2006-2009 in the ICU for adults and general surgery wards of two large teaching clinics for emergencies in Bucharest municipality. Associations between fatal outcome and relevant demographic and clinical characteristics were analyzed both through cohort and also by case-control studies.

RESULTS

in the cohort analysis both the severity of the underlying disease and also the presence of HAl with MDR strains of P. aeruginosa or A. baumanii were statistical significant (p < 0.05) and independently associated with fatal outcome; the presence of HAI with MDR strains of P. aeruginosa or A. baumanii remained significant associated with fatal outcome even after controlling of the underlying disease's severity by case-control design (Match OR: 5.89; 95% IC: 1.39-40.77; p = 0.011).

CONCLUSIONS

the study's results demonstrate that the precautions to prevent the in hospital transmission of the MDR germs are pertinent because the HAI induced by these bugs is obviously associated with unfavorable clinical outcome of the patient.

Factors influencing survival in patients with multi-drug-resistant Acinetobacter bacteraemia

OBJECTIVES

The incidence of multi-drug-resistant (MDR) Acinetobacter strains is increasing and therapeutic options are limited. However, controversy exists regarding the mortality attributable to antimicrobial resistance. The aim of this study was to analyse the clinical features and outcomes of patients with MDR Acinetobacter calcoaceticus-Acinetobacter baumannii complex (Acb complex) bacteraemia and determine the factors influencing survival by using 14-day mortality as the main outcome measure.

METHODS

An observational study was conducted at a tertiary care hospital in Turkey from February 2007 to March 2008. Only one bacteraemic episode from one patient was included in the study.

RESULTS

A total of 100 clinically significant Acb complex bacteraemic episodes were detected. The overall mortality was 63% in 14 days. According to univariate analysis, diabetes mellitus, haematological malignancy, unknown source of bacteraemia, septic shock, resistance to carbapenems, and inappropriate empirical therapy were associated with mortality amongst patients with Acb complex bacteraemia. Multivariate analysis showed that diabetes mellitus (RR, 1.68; 95% CI, 1.22-1.76), carbapenem resistance (RR, 1.63; 95% CI, 1.19-1.89), and septic shock (RR, 1.65; 95% CI, 1.23-1.85) were independent risk factors for 14-day mortality.

CONCLUSION

Although severe underlying diseases play an important role in the clinical outcome of patients with Acb complex bacteraemia, carbapenem resistance and inappropriate therapy are of great concern. Special attention should be paid to infection control practices in the hospitals where MDR Acinetobacter infections are endemic, and well-controlled prospective clinical trials are needed to determine the optimal antimicrobial therapy in critically ill patients suspected of having MDR Acinetobacter bacteraemia.

Role of tigecycline in the control of a carbapenem-resistant Acinetobacter baumannii outbreak in an intensive care unit

The incidence of Acinetobacter baumannii infection has greatly increased over recent decades with infections occurring more in critically ill hospitalised patients. Hospital outbreaks of multiple antibiotic-resistant strains are posing an increasing threat to public health. Three different outbreaks of multidrug-resistant A. baumannii (MRAB) infections involving 24 patients, aged 16-75 years occurred in the intensive care unit in the course of one year. The isolates were cultured from clinical samples and identified using automated Vitek II ID system and the API 20NE system. Susceptibility testing was done by the E-test method. Molecular typing of the isolates was determined by pulsed-field electrophoresis. Screening of both patients and the environment was carried out. The acquisition time, i.e. the time of admission to time of acquiring infection, ranged from 3 to 31 days. All isolates were multiply resistant (MRAB), including resistance to carbapenems (MRAB-C) in the majority of cases but susceptible to tigecycline, with a minimum inhibitory concentration (MIC(90)) of 2 microg/mL. The overall mortality rate was 16.7%. Time-to-clearance of the MRAB-C was 8.3 days in the first outbreak, when tigecycline was not used, and 2.8 and 3.1 days during the second and third outbreaks, respectively, when tigecycline was used, and all but one patient survived. Environmental screening revealed gross contamination of many surfaces and equipment within the unit. The outbreak strains belonged to two distinct clones (D and E) whereas the 14 environmental strains belonged to three distinct groups (A-C). The outbreak of infections treated with tigecycline was successfully eliminated in conjunction with an aggressive infection control strategy.

Attributable mortality of imipenem-resistant nosocomial Acinetobacter baumannii bloodstream infection

BACKGROUND

Uncertainty remains concerning the mortality attributable to infections caused by imipenem-resistant acinetobacter baumannii (IRAB). The authors have sought to examine the impact of this resistance on patient mortality.

OBJECTIVE

To evaluate the effects of imipenem resistance on the mortality of patients with Acinetobacter baumannii bloodstream infection.

MATERIAL AND METHOD

A cohort study was conducted to compare the survival rates between patients with IRAB and imipenem-susceptible A. baumannii (ISAB) bacteremia.

RESULTS

The present study shows 35 patients (52.2%) in an IRAB group died in hospital compared to 26 patients (19.9%) in an ISAB group (p < 0.001). Multivariate analysis using Cox's proportional hazard model for controlling the confounding effects due to the severity of underlying diseases, inappropriate antibiotic treatment, and primary source of bacteremia show no statistically significant difference in mortality rates between the two groups.

CONCLUSION

The observed higher mortality rate among patients with an IRAB bloodstream infection may not be attributable to imipenem resistance but may in some part be due to a more severe illness, inappropriate antimicrobial therapy, and primary source of infection.

Outcomes and appropriateness of management of nosocomial Acinetobacter bloodstream infections at a teaching hospital in northeastern Malaysia

Acinetobacter spp is a known nosocomial pathogen causing a wide range of clinical diseases such as pneumonia, wound infection and bloodstream infections (BSI). The clinical outcomes of acinetobacter BSI were determined by a 1:1 case control study involving 58 confirmed cases of acinetobacter BSI who were compared to other gram-negative infections. The crude mortality of acinetobacter BSI was 47.2%, which was significantly greater than other gram-negative BSI (OR 1.89, 95% CI 1.10-3.24) but there were no significant differences in attributed mortality between the two groups. We found that patients treated in intensive care units (ICU), who had longer ICU stays, who presented with shock or coagulopathy, had prior exposure to carbapenems, had mechanical ventilation, were on a ventilator for longer periods, had a nasogastric tube, had an arterial catheter or had parenteral nutrition at a significantly greater risk of mortality due to acinetobacter BSI. Patients presenting with septic shock (OR 17.95, 95% CI 3.36-95.84) or having a central venous catheter (OR 12.48, 95% CI 1.09-142.68) were independently at higher risk for mortality. Appropriateness of therapy reduced the mortality attributes of acinetobacter BSI (OR 0.197, 95% CI 0.040-0.967) but did not significantly reduce crude mortality in acinetobacter BSI patients. This study shows the importance of preventing acinetobacter BSI and the appropriate use of antimicrobial agents to reduce mortality.

Efficacy of monotherapy and combined antibiotic therapy for carbapenem-resistant Acinetobacter baumannii pneumonia in an immunosuppressed mouse model

Acinetobacter baumannii is an important cause of nosocomial infection with increasing carbapenem resistance. The aim of this study was to compare the efficacy of colistin+rifampicin and imipenem+rifampicin combinations with that of several other antibiotic regimens against carbapenem-resistant A. baumannii pneumonia using an immunosuppressed mouse model. Three different A. baumannii strains with diverse resistance mechanisms (OXA-51-, IMP-1- and VIM-2-type beta-lactamases) were used. Among the monotherapy regimens, only rifampicin significantly reduced the bacterial load in lungs 24 h after infection with the OXA-51-producing strain. Addition of rifampicin to either imipenem or colistin yielded synergistic results after 48 h. Rifampicin was bactericidal against the IMP-1-producing strain, and only the imipenem+rifampicin combination yielded synergistic effects. In contrast, rifampicin alone was not effective against the VIM-2-producing strain, but the imipenem+rifampicin combination was bacteriostatic even at 24 h post-infection. Tigecycline and amikacin were not effective against any of the three strains. Rifampicin-based combinations were effective against A. baumannii bacteraemia and improved survival regardless of the strain type. Contrary to the similar minimum inhibitory concentration results, the antibacterial effects of rifampicin were quite different according to the strains; a tailored antibiotic strategy must be considered in treatment. Addition of rifampicin to either imipenem or colistin would be effective.

Risk factors for mortality in patients with Acinetobacter baumannii bloodstream infection with genotypic species identification

BACKGROUND AND PURPOSE

Acinetobacter baumannii is an increasingly common nosocomial infection with a high mortality rate. Identification of predictor factors of mortality from A. baumannii infection is important for the implementation of therapeutic management for patients with higher risk. However, many studies have reported data for Acinetobacter calcoaceticus-A. baumannii complex, which might lead to an uncertainty of results. In this study, we aimed to identify the predictive factors for mortality of patients infected with true A. baumannii that had been precisely identified by genotypic methodology.

METHODS

Sixty seven patients with documented A. baumannii bacteremia were identified from a medical center in northern Taiwan during the period between February 1998 and February 2001. The patients' medical records were retrospectively reviewed.

RESULTS

The risk factors associated with mortality in patients with A. baumannii bacteremia were underlying disease with malignancy, end-stage renal disease, and inappropriate antibiotic therapy. Laboratory variables, such as creatinine level, were also associated with poor prognosis by multivariate analysis.

CONCLUSIONS

Increased serum creatinine level, malignancy and inappropriate therapy within 3 days were related to increased mortality in patients with A. baumannii bloodstream infection. Physicians should be aware of patients with poor prognostic factors and initiate prompt strategies, including appropriate antimicrobial therapy, in order to reduce mortality.

Attributable mortality of Acinetobacter baumannii: no longer a controversial issue

There has been controversy regarding the mortality directly attributed to Acinetobacter baumannii infections. Data from six case–control studies have been recently added to the literature regarding the attributable mortality of A. baumannii infections during the past months. The information from these studies, added to the previous knowledge on this issue, provides evidence that A. baumannii infections are indeed associated with increased mortality. In addition, there is relevant evidence from studies examining the effect of inappropriate treatment on mortality; specifically, inappropriate treatment of A. baumannii infections has been associated with excess mortality. We believe that the accumulated data suggest that attributable mortality due to A. baumannii infections should no longer be a controversial issue. The efforts of the scientific community interested in this pathogen should therefore be directed to the development and introduction of new antibiotics effective against multidrug-resistant and pandrug-resistant A. baumannii as well as the implementation of infection control measures that may help us in the control of the increasing problem of A. baumannii infections.

Multidrug-resistant Acinetobacter baumannii in ventilator-associated pneumonia at a medical center in southern Taiwan

BACKGROUND AND PURPOSE

To evaluate the significance of multidrug-resistant Acinetobacter baumannii (MDRAB)-related ventilator-associated pneumonia at a medical center in southern Taiwan.

METHODS

We retrospectively reviewed the medical records of patients with MDRAB isolated from sputum and described the characteristics of these patients. Patients were divided into 2 groups according to their clinical pulmonary infection scores (CPIS), and their host factors and outcomes compared.

RESULTS

In the patient group with significant MDRAB-related lung infection, Acute Physiology and Chronic Health Evaluation II scores were significantly higher than in those patients with lower CPIS scores (<6). However, the clinical outcomes, including the duration of hospitalization after isolation of MDRAB and mortality rate, were not different.

CONCLUSION

Our investigation showed that significant lung infections with MDRAB isolation did not result in prolonged hospitalization or increased mortality. The initial clinical severity of the group with significant MDRAB-related lung infection was significantly greater than in the other. We propose that MDRAB-related pneumonia should be regarded as a signal of the clinical severity of the patient rather than as a prognostic factor.

Multidrug-resistant Acinetobacter baumannii isolates in pediatric patients of a university hospital in Taiwan

BACKGROUND AND PURPOSE

Acinetobacter baumannii is one of the common nosocomial pathogens, and the emergence of multidrug-resistant A. baumannii (MDRAB) is a therapeutic problem. We describe the clinical characteristics and outcomes of MDRAB colonization/infection in pediatric patients at the National Taiwan University Hospital.

METHODS

Fifty two pediatric patients with 205 MDRAB isolates collected between April 2000 and December 2005 were included for investigation of their clinical characters, presentations, and outcome.

RESULTS

Among these 205 isolates, 20 (9.8%) were from sterile body sites (11 from blood, 8 from catheter tips, and 1 from ascites), 154 (75.1%) from respiratory sites, 18 (8.8%) from skin or wound pus, 5 (2.4%) from urine, and 8 (3.9%) from other sites. The mean age was 6 years. The common underlying diseases were haematological or oncological diseases (n = 15, 28.8%), neonatal disorders (6, 11.5%), cyanotic congenital heart diseases (10, 19.2%), neurology disorders (12, 23.1%), and gastrointestinal tract disorders (3, 5.8%). Seventeen patients (32.7%) had received major surgery, and 48 (92.3%) had used ventilators. Fourteen patients (26.9%) had neutropenia and 46 (88.5%) had used broad-spectrum antibiotics. There were 31 patients (59.6%) with suspected or proven MDRAB infections, including sepsis (9 patients), pneumonia (19), wound infections (3), urinary tract infections (2), peritonitis (1), and perineal infection (1). Seven (77.8%) of the 9 sepsis patients died. The overall mortality rate was 42.3% (22 cases).

CONCLUSIONS

The threat of MDRAB has been recognized in our hospital for several years. Host defense deficiencies, prolonged intensive care unit hospitalizations, and prior broad-spectrum antibiotic use play a major role in MDRAB infection and colonization.

Prognosis of adult patients with bacteremia caused by extensively resistant Acinetobacter baumannii

Nosocomial bacteremia caused by extensively resistant Acinetobacter baumannii (ERAB) is an emerging problem in Taiwanese hospitals. Accordingly, we retrospectively investigated the epidemiology and outcomes of adult patients with ERAB bacteremia (ERABB) after different treatments from January 2001 to September 2004 at the National Taiwan University Hospital, Taipei, Taiwan. A total of 56 adult patients with ERABB and without other simultaneous infections were enrolled. Demographic, clinical, and laboratory data were obtained from medical records. Clinical data included underlying diseases and conditions with onset within 7 days after ERABB, severity of ERABB, antibiotic regimens for ERABB, and clinical outcomes. Laboratory data included hemograms, liver function tests, renal function tests, and albumin levels. Coagulation profiles were obtained at ERABB onset and 7 days before and after onset. All 56 episodes of ERABB were hospital-acquired. Most patients had Acute Physiology Scores and Chronic Health Evaluation II scores >/=17 (66.1%) and Pitt bacteremia score >/=4 (66.1%). Many had comorbid diseases at ERABB onset. Crude mortality rates on days 2, 7, 15, 30, and at discharge were 23.2%, 30.4%, 37.5%, 48.2%, and 60.7%, respectively. High severity of ERABB (Pitt bacteremia score >/=4) and presence of immunosuppression were the only 2 predictors for day 30 mortality (odds ratios of 18.53 and 8.06, respectively). Antibiotic regimens for ERABB did not have a significant influence on ERABB outcomes.

Exposure to quinolones is associated with carbapenem resistance among colistin-susceptible Acinetobacter baumannii blood isolates

In this study, we explored risk factors associated with bacteraemia caused by colistin-susceptible/carbapenem-resistant (Co(S)/Ca(R)) Acinetobacter baumannii. A retrospective cohort study of hospitalised patients with A. baumannii bacteraemia was performed at a tertiary care hospital over a 44-month period. Thirty-nine patients with bacteraemia due to A. baumannii (35 Intensive Care Unit and 4 ward patients) were included in the analysis. Twenty-five patients (64%) had bacteraemia due to Co(S)/Ca(R)A. baumannii and 14 patients (36%) had bacteraemia due to colistin-susceptible/carbapenem-susceptible A. baumannii. Mortality was 56% (14/25) and 35.7% (5/14) for patients in the two groups, respectively (P=0.22). Bivariate analysis showed that prior exposure to fluoroquinolones (P=0.01) and antipseudomonal penicillins (P=0.004) as well as a higher number of antibiotics in use on the day of bacteraemia (P=0.02) were associated with isolation of a Co(S)/Ca(R) strain among patients with A. baumannii bacteraemia. Multivariate analysis using a backward logistic regression model showed that only exposure to fluoroquinolones was associated with development of Co(S)/Ca(R)A. baumannii bacteraemia (odds ratio=11.6; 95% confidence interval 2.4-55.9; P=0.02). The appearance of Co(S)/Ca(R)A. baumannii infections represents a major threat to critically ill hospitalised patients. Exposure to fluoroquinolones is an independent risk factor for development of Co(S)/Ca(R)A. baumannii bacteraemia.

Impact of multi-drug-resistant Acinetobacter baumannii on clinical outcomes

We conducted a retrospective matched cohort study to examine the impact of isolation of multi-drug-resistant (MDR) Acinetobacter baumannii on patient outcomes. Cases from whom MDR A. baumannii was isolated in a clinical culture (n = 118) were compared with controls from whom MDR A. baumannii was not isolated (n = 118). Cases and controls were matched according to ward, calendar month of hospitalization, and duration of hospitalization before culture. The following outcomes were compared in multivariable analysis: in-hospital mortality, length of stay, need for mechanical ventilation, and functional status at discharge. MDR A. baumannii was determined to be a pathogen in 72% of cases. In 36% of cases, the patient died, versus 21% of controls (odds ratio [OR] 2.21, 95% confidence interval [CI] 1.17-4.16, P = 0.014). Median length of stay for surviving cases was 17 days, versus 11 for surviving controls (multiplicative effect 1.55, 95% CI 0.99-2.44, P = 0.057). Fifty-two percent of cases required mechanical ventilation, versus 25% of controls (OR 3.72, 95% CI 1.91-7.25, P<0.001); 60% of surviving cases were discharged with reduced functional status, versus 38% of controls (OR 4.4, 95% CI 1.66-11.61, P = 0.003). In multivariable analysis, clinical isolation of MDR A. baumannii remained a significant predictor of mortality (OR 6.23, 95% CI 1.31-29.5, P = 0.021), need for mechanical ventilation (OR 7.34, 95% CI 2.24-24.0, P<0.001), and reduced functional status on discharge (OR 7.93, 95% CI 1.1-56.85, P = 0.039). Thus, MDR A. baumannii acquisition is associated with severe adverse outcomes, including increased mortality, need for mechanical ventilation, and reduced functional status.

Outcomes ofAcinetobacter baumanniiInfection in Critically Ill Surgical Patients

BACKGROUND

Multi-drug resistant (MDR) organisms in intensive care units (ICUs) are a growing concern. The emergence of several infections with MDR Acinetobacter baumannii prompted a review of cases and evaluation of the efficacy of intervention.

OBJECTIVE

To determine the rate of clinical cure, the incidence of drug resistance, and the mortality rate associated with A. baumannii infection.

METHOD

Retrospective review of A. baumannii infections in three surgical ICUs between January, 2004 and November, 2005. Infection was identified in 291 patients, 20 of whom were excluded because of incomplete documentation. Of the remaining 271 patients, 71% were male, and the mean age was 47 +/- 18 years (range 13-90 years).

RESULTS

Patients had a mean length of stay in the ICU of 14 days (range 0-136 days) before infection. The initial positive cultures were from bronchoalveolar lavage fluid (BAL) in 72.3%, blood in 16.2%, a catheter tip in 6.3%, urine in 1.8%, wound in 2.2%, and abscess in 1.1%. In 46.9% of patients, the first culture was polymicrobial. The Acinetobacter isolates were resistant or intermediate-resistant to imipenem-cilastatin in 81.2% of cases; 19.9% were resistant to all drugs except colistin, and two were resistant to all tested drugs. Colistin was used in 75.6% of patients (intravenous 61.5%, nebulized 38.5%). The mean duration of treatment was 13 +/- 8.9 days (range 0-56 days), and clinical cure was achieved in 73.8% of patients. Recurrent infection after initial cure was found in 19.2% of patients. There was no significant difference in clinical cure rates between patients treated with colistin and those treated with other culture-directed drugs (75.1% vs. 69.7%), or between patients treated with intravenous vs. nebulized colistin (72.4% vs. 79.5%). The mortality rate was 26.2% for the entire group and was significantly higher in the subgroup of transplant patients (n = 31) (64.5% vs. 21.4%; p < 0.001).

CONCLUSION

The majority of A. baumannii isolates were MDR, and a significant proportion were sensitive only to colistin. Treatment of A. baumannii infection with colistin is effective by both intravenous and nebulized routes of administration. However, infection with A. baumannii in critically ill surgical patients is associated with a high mortality rate, particularly in transplant patients.

Predictive value of the serum bactericidal test for mortality in patients infected with multidrug-resistant Acinetobacter baumannii

OBJECTIVE

Strains of Acinetobacter baumannii resistant to all available antibiotics except polymyxin B have circulated in Taiwan since 1998 and have caused a variety of nosocomial infections. There are no standard tests to measure outcome in patients infected with these strains. Our aim was to determine whether a serum bactericidal test (SBT) could be used for this purpose.

METHODS

This SBT was performed in 57 infected patients.

RESULTS

Among the 35 patients who survived and 22 patients who died, peak SBT titer negatively correlated with mortality rate (correlation coefficient -0.43). The survival rate in patients with a peak SBT titer > or = 1:16, > or = 1:8, and < or = 1:4 was 100%, 87.5%, and 42.4%, respectively (p=0.001). Mortality was found to be closely related to illness severity and the presence of multiple organ failure. In subgroup analysis, the power of SBT to predict mortality was significant for patients without multiple organ failure (p=0.004), and also patients without disease defined as rapidly fatal by McCabe classification (p=0.044).

CONCLUSION

In a region with few therapeutic options for multi-drug resistant Acinetobacter baumannii (MDRAB), such as in Taiwan, SBT could be used as a prognosis indicator and indicator of the need to modify treatment in patients infected with MDRAB.

Postsurgical meningitis caused by Acinetobacter baumannii associated with high mortality

Twenty five (25) cases of nosocomial postsurgical meningitis due to Acinetobacter baumannii meningitis were compared to other 146 cases of meningitis after surgery caused by other pathogens. Prior neurosurgical ventriculo-peritoneal shunt insertion and CNS abnormality as well as very low birth weight were significant risk factors for acquisition of Acinetobacter baumannii meningitis. Mortality - 40% among children with nosocomial meningitis was unacceptably high and significantly higher than among meningitis caused by microorganisms other than Acinetobacter baumannii.

Carbapenems for the treatment of immunocompetent adult patients with nosocomial pneumonia

The comparative effectiveness and safety of carbapenems with other beta-lactams and fluoroquinolones for the empirical treatment of patients with hospital-acquired pneumonia remains controversial. In the present study, a meta-analysis of 12 relevant randomised controlled trials was performed. Overall, carbapenems were associated with lower mortality than fluoroquinolones or beta-lactams, alone or in combination with aminoglycosides (odds ratio 0.72, 95% confidence interval 0.55-0.95). There was no difference between the compared antibiotics regarding treatment success (1.08, 0.91-1.29), microbiological success (1.04, 0.72-1.50) or development of adverse effects (0.81, 0.46-1.43). In the subset of patients with Pseudomonas aeruginosa pneumonia, carbapenems were associated with lower treatment success (0.42, 0.22-0.82) and lower eradication of P. strains (0.50, 0.24-0.89). Carbapenems are equivalent to fluoroquinolones or beta-lactams, alone or in combination with aminoglycosides, for the empirical treatment of immunocompetent adult patients with hospital-acquired pneumonia. However, there is limited evidence, based predominantly on unblinded randomised controlled trials, that carbapenems are associated with lower mortality than the comparators; this association was not observed in a subset analysis of randomised controlled trials with a high methodological quality score. In patients with Pseudomonas aeruginosa pneumonia, carbapenems are associated with worse outcomes than the comparators.

Clinical and economic impact of multidrug resistance in nosocomial Acinetobacter baumannii bacteremia

OBJECTIVE

To investigate the impact of antimicrobial resistance on clinical and economic outcomes among hospitalized patients with multidrug-resistant (MDR) Acinetobacter baumannii bacteremia.

DESIGN

A retrospective, matched-cohort study.

SETTING

A tertiary care university teaching hospital.

METHODS

A matched case-control (1 : 1) study was conducted to compare the differences in clinical and economic outcomes of patients with MDR A. baumannii bacteremia and patients with non-MDR A. baumannii bacteremia. Case patients were matched to control patients on the basis of sex, age, severity of underlying and acute illness, and length of hospital stay before onset of bacteremia.

RESULTS

Forty-six (95.8%) of 48 cases with MDR A. baumannii bacteremia were eligible for the study and matched with appropriate controls. The sepsis-related mortality rate was 34.8% among cases and 13.0% among controls, for an attributable mortality rate of 21.8% (adjusted odds ratio, 4.1 [95% confidence interval, 1.1-15.7]; P=.036). After the onset of bacteremia, cases and controls had a significantly different length of hospital stay (54.2 vs 34.1 days; P=.006), hospitalization cost (US$9,349 vs US$4,865; P=.001), and antibiotic therapy cost (US$2,257 vs US$1,610; P=.014). Thus, bacteremia due to MDR A. baumannii resulted in 13.4 days of additional hospitalization and US$3,758 of additional costs, compared with bacteremia due to non-MDR A. baumannii.

CONCLUSIONS

Patients with MDR A. baumannii bacteremia had a higher mortality rate and incurred greater medical costs than patients with non-MDR A. baumannii bacteremia.

Outcomes of Acinetobacter baumannii infection in critically ill burned patients

The objective of this study was to determine the incidence of drug resistance among isolates of Acinetobacter baumannii from our Burn Intensive Care Unit (BICU), the rate of clinical cure, and the mortality rate. We undertook a retrospective review of all cases of infection from the BICU between January 2004 and November 2005. The group consisted of 24 men (80%) and 6 women with a mean age of 43 years (range, 17-76 years, +/-14.5 years). Mean TBSA burned was 43% (range, 9-75%, +/-19%). Mean BICU length of stay was 49 days (range, 5-118 days, +/-30 days). Patients developed their first infection after a mean of 16 days (5-73 days, +/-14 days). The initial site of infection was bronchoalveolar lavage in 21 (70%), blood in 6 (20%), central venous catheter tip in 2 (7%), and urine in 1 (3%). The isolates displayed resistance to imipenem in 87% of cases. No organism displayed resistance to colistin (polymixin E). Patients were treated with colistin in 20 cases (67%), with amikacin in 8 cases (27%), and with imipenem in 2 cases (7%). A total of 10 patients (33%) died, 1 from gastrointestinal bleeding and 9 from active infection, giving an infection related mortality of 30%. In 21 cases (70%), a cure was achieved with a mean duration of treatment of 16 days (range, 4-30 days, +/-7 days). The majority of A. baumannii isolates were multidrug resistant; however, no isolate displayed resistance to colistin. Cure rate was 70% and infection-related mortality reached 30%. More investigation is warranted to improve prevention and to assess new therapeutic agents.