Risk factors and impact of nosocomial Acinetobacter baumannii bloodstream infections in the adult intensive care unit: a case-control study

Strong Homology Between Colonizing and Bloodstream Carbapenem-Resistant Acinetobacter Spp.: Implications for Empiric Antibiotic Therapy in Hematological Patients

Objective

This study aimed to assess the impact of colonization status on the outcomes of Acinetobacter spp. bloodstream infection (BSI) and investigate the homology and within-host evolution between colonizing and bloodstream carbapenem-resistant Acinetobacter spp. (CRA) to inform antibiotic therapeutic decisions.

Methods

We analyzed clinical outcomes of 46 hematological patients with Acinetobacter spp. BSI and performed whole-genome sequencing on the remaining CRA isolates.

Results

Among the patients, 39.1% (n=18) had prior Acinetobacter spp. colonization. Colonized patients had higher rates of polymicrobial BSI (50.0% vs 21.4%, P=0.044) and CRA BSI (72.2% vs 17.9%, P<0.001), resulting in elevated inflammatory markers and increased 30-day mortality. Each of the eight pairs of the remaining respiratory colonizing and bloodstream CRA strains belonged to the same genomospecies. Each pair exhibited definitive agreement in at least 21 of the 22 most representative antibiotic susceptibility tests. The minimum spanning tree based on multilocus sequence typing (MLST) and phylogenetic trees based on MLST and single nucleotide polymorphism (SNP) all indicated that each pair shared the same minimum branch. Very few non-synonymous SNPs in genic regions were identified during the transition from respiratory colonization to bloodstream infection, with minimal changes in virulence genes. Homology analysis suggested that CRA BSI originated from colonizing isolates in the respiratory tract.

Conclusion

Strict infection control measures are needed to manage Acinetobacter spp. colonisation in hematological patients. Appropriate empirical therapy can be administered for suspected CRA BSI based on the antimicrobial minimum inhibitory concentration of CRA colonising the respiratory tract.

Risk factors for bacteremia and mortality due to multidrug-resistant Acinetobacter baumannii: a retrospective study

This research aimed to determine the relationships between the risk factors for nosocomial multidrug-resistant Acinetobacter baumannii (MDRAB) bacteremia and associated mortality. We analyzed 144 patients treated for A. baumannii bacteremia, including 120 patients with MDRAB bacteremia, from March 2015 to March 2020, in this retrospective study. The overall bacteremia-related mortality rate was 48.6%. The mortality rates were 25.0% and 53.3% for non-MDRAB and MDRAB bacteremia, respectively. Risk factors for the development of MDRAB bacteremia were prior use of cephalosporins [odds ratio (OR): 8.62; P < .001], carbapenems (OR: 15.04; P < .001), or quinolones (OR: 5.02; P = .040); indwelling urinary catheters (OR: 21.38; P < .001); and respiratory tract as the source of bacteremia (OR: 75.33; P < .001). Patients with elective surgeries were inclined to develop non-MDRAB bacteremia (OR: 0.45; P = .029). High scores in the Acute Physiology and Chronic Health Evaluation II (OR: 1.321; P < .001) and Sequential Organ Failure Assessment (OR: 1.326; P < .001) were risk factors for mortality from MDRAB infection. In summary, higher mortality rates occur in patients with MDRAB bacteremia, and risk factors include prior use of cephalosporins, carbapenems, or quinolones. Urinary catheters and the respiratory tract as sources of the infection increase the risk of MDRAB bacteremia.

Shift in risk factors for mortality by period of the bloodstream infection timeline

BACKGROUND

This study was designed to determine changes in risk factors on the prognosis of patients during each period of the bloodstream infection (BSI) timeline.

METHODS

Through an integrated study of multivariable regressions with machine learning techniques, the risk factors for mortality during each period of BSI were analyzed.

RESULTS

A total of 302,303 inpatients who underwent blood cultures during 2011-2021 were enrolled. More than 8 % of BSI cases progressed to subsequent BSI, and risk factors were identified as gut colonization with vancomycin-resistant enterococci (aOR 1.82; 95 % CI 1.47-2.24), intensive care unit admission (aOR 3.37; 95 % CI 3.35-4.28), and current cancer chemotherapy (aOR 1.54; 95 % CI 1.36-1.74). The mean SOFA score of the deceased patients during the first 7 days was 10.6 (SD 4.3), which was significantly higher than those on days 8-30 (7.0 ± 4.2) and after Day 30 (4.0 ± 3.5). BSIs caused by Acinetobacter baumannii and Candida albicans were more likely to result in deaths of patients for all time periods (all, P < 0.001). BSIs caused by Enterococcus faecalis and Enterococcus faecium were associated with a poor outcome in the period after Day 30 (both, P < 0.001). Nonsusceptible phenotypes to β-lactam/β-lactamase inhibitors of Escherichia coli and Klebsiella pneumoniae influenced the prognoses of patients with BSI in terms of high mortality rates during both days 8-30 and after Day 30.

CONCLUSION

Influence of microbiological factors on mortality, including BSI-causative microorganisms and their major antimicrobial resistance, was emphasized in both periods of days 8-30 and after Day 30.

Dynamic monitoring of neutrophil/lymphocyte ratio, APACHE II score, and SOFA score predict prognosis and drug resistance in patients with Acinetobacter baumannii-calcoaceticus complex bloodstream infection: a single-center retrospective study

Objective

This study aimed to evaluate the clinical value of dynamic monitoring of neutrophil/lymphocyte ratio (NLR), APACHE II (Acute Physiology and Chronic Health Evaluation II) score, and Sequential Organ Failure Assessment (SOFA) score in predicting 28-day prognosis and drug resistance in patients with bloodstream infection with Acinetobacter baumannii-calcoaceticus complex (Abc complex).

Patients and methods

In this research, individuals admitted to Tianjin Medical University General Hospital from January 2017 to March 2023 with bloodstream infections and a minimum of one Abc complex positive blood culture were chosen. The risk factors for the 28-day prognosis and drug resistance were analyzed using logistic regression. The NLR, APACHE II score, and SOFA score were evaluated for predicting 28-day prognosis and drug resistance using an ROC curve analysis. The data were analyzed using R Studio to find correlations and conduct survival analysis with the Kaplan-Meier method.

Results

The final statistical analysis included a total of 129 patients with bloodstream infections caused by Abc complex. Independent risk factors predicting mortality within 28 days were identified as follows: the SOFA score and APACHE II scores at 24 h, and APACHE II scores at 72 h after the onset of blood infection (p < 0.05). NLR, SOFA score, and APACHE II score did not predict drug resistance. Patients with Carbapenem-resistant Acinetobacter baumannii-calcoaceticus complex (CRAB) had shorter survival times than those with carbapenem-sensitive strains (40.77 days vs. 47.65 days, respectively, p = 0.0032).

Conclusion

The prognosis of Abc complex bloodstream infection is affected by both SOFA and APACHE II scores. Both scoring systems have similar prognostic values at different time points after infection, but for computational convenience, it is recommended to use the SOFA score. NLR exhibits limited effectiveness in predicting mortality within 28 days. Carbapenem-resistant individuals with Abc complex experience significantly reduced survival time. None of the three factors-SOFA score, APACHE II score, and NLR-can early predict the occurrence of CRAB infections effectively.

Risk Factors for Post-Operative Multi-Drug-Resistant Organism Bacterial Infection in Patients With Stanford Acute Type A Aortic Dissection

Background: To explore the risk factors for multi-drug-resistant organism (MDRO) infection in patients with Stanford acute type A aortic dissection (ATAAD). We conducted a retrospective cohort study using the data of post-operative patients with ATAAD in our hospital. Patients and Methods: This study included 82 post-operative patients with ATAAD in the past decade. They were divided into a MDRO group (n = 31) and a non-MDRO group (n = 51) according to whether they had acquired multi-drug-resistant (MDR) bacterial infection. Multivariable logistic regression was used to analyze the risk factors for MDR infections in patients with ATAAD. Results: The incidence of multi-drug-resistant bacterial infection was 37.80%. Seventeen factors, including hospital stay (p = 0.007), utilization of third-generation cephalosporins (p = 0.0068), antibiotic species of exposure (p = 0.0002), leukocyte-depleted red blood cell suspension dosage (p < 0.0001), fresh frozen plasma dosage (p < 0.0001), application of blood purification (p = 0.0493), and the total antibiotic days of exposure (p = 0.0001) diverged between the two groups (all p < 0.05). The logistic regression analysis revealed that the utilization of third-generation cephalosporins (odds ratio [OR], 2.32; 95% confidence interval [CI], 1.01-5.33; p = 0.0478), antibiotic species of exposure (OR, 5.76; 95% CI, 1.45-22.83; p = 0.0128), leukocyte-depleted red blood cell suspension dosage (OR, 12.43; 95% CI, 2.71-57.07; p = 0.0012), and fresh frozen plasma dosage (OR, 5.05; 95% CI, 1.18-21.56; p = 0.0286) were independent variables for MDRO infections. Among the 23 drug-resistant bacteria detected, Acinetobacter baumannii was the main pathogen. Conclusions: Our study shows that the utilization of third-generation cephalosporins, antibiotic species of exposure, leukocyte-depleted red blood cell suspension dosage, and fresh frozen plasma dosage were independent risk factors for post-operative multi-drug-resistant infection in patients with ATAAD. Acinetobacter baumannii occupied the largest share of resistant bacteria that induce infection in post-operative patients with ATAAD.

Acinetobacter spp. bloodstream infection in hematological patients: a 10-year single-center study

PURPOSE

This study investigated the clinical and antimicrobial characteristics of Acinetobacter spp. bloodstream infection (BSI) in hematological patients. Risk factors for 30-day mortality and carbapenem-resistant Acinetobacter spp. (CRA) BSI acquisition were also identified.

METHODS

We reviewed forty hematological patients with Acinetobacter spp. BSI in a large Chinese blood disease hospital between 2013 and 2022. The remaining CRA isolates were subjected to whole-genome sequencing.

RESULTS

The 30-day mortality rate was high at 35%. Hematological patients with Acinetobacter spp. BSI often presented with severe conditions and co-infections at multiple sites. All strains were colistin-susceptible and 40.0% were CR. Multivariate analysis identified several risk factors associated with CRA BSI acquisition, including previous exposure to carbapenems within 30 days and CRA colonization. Very severe aplastic anaemia, tetracycline-resistant Acinetobacter spp. BSI, and unresolved neutropenia after infection were closely associated with 30-day mortality. Non-survivors often presented with higher median PCT and CRP levels and severe complications, such as intracranial infection, cardiac dysfunction, respiratory failure, and severe sepsis or septic shock. Our study also identified inappropriate empirical antibiotic therapy as an independent predictor of 30-day mortality (OR: 11.234, 95% CI: 1.261-20.086, P = 0.030). This study was the first to report A. oleivorans as a human pathogen, and to identify its unique oxacillinase, OXA-325.

CONCLUSION

An environment-originated non-pathogenic species can become pathogenic when the body's immunity is compromised. Our results also highlighted the importance of improving neutropenia after infection, treating severe organ dysfunction, and administering appropriate empirical antibiotic therapy to reduce mortality in this patient population.

Risk factors for progression to bacteremia among patients with nosocomial carbapenem-resistant Acinetobacter baumannii pneumonia in the Intensive Care Unit

Antibiotic-resistant Acinetobacter baumannii (A. baumannii) is a common cause of hospital-acquired infections. This study aimed to identify independent factors associated with progression from nosocomial pneumonia to bacteremia in patients infected with carbapenem-resistant A. baumannii (CR-AB). From 2019 to 2021, we conducted a retrospective anaylsis of the medical records of 159 nosocomial CR-AB pneumonia patients in our Intensive Care Unit (ICU). We employed both univariate and multivariable logistic regression models to identify factors associated with the progression of nosocomial CR-AB pneumonia to bacteremia. Among the 159 patients with nosocomial CR-AB pneumonia, 40 experienced progression to bacteremia and 38 died within 28 days following diagnosis. Patients who developed bacteremia had a significantly higher 28-day mortality rate compared to those without bloodstream infection (47.50% vs. 15.97%). Multivariable logistic regression revealed that higher levels of C-Reactive protein (CRP) (OR = 1.01) and the use of continuous veno-venous hemofiltration (CVVH) treatment (OR = 2.93) were independently associated with an elevated risk of developing bacteremia. Among patients who developed bloodstream infection, those who died within 28 days exhibited significantly higher level of interleukin-6 (IL-6), a greater frequency of antifungal drugs usage, and a longer duration of machanical ventilation compared to survivors. Furthermore, the use of antifungal drugs was the only factor that associated with 28-day mortality (OR = 4.70). In ICU patients with central venous catheters who have CR-AB pneumonia and are on mechanical ventilation, higher CRP levels and CVVH treatment are risk factors for developing bacteremia. Among patients with bacteremia, the use of antifungal drugs is associated with 28-day mortality.

Healthcare Equipment and Personnel Reservoirs of Carbapenem-Resistant Acinetobacter baumannii Epidemic Clones in Intensive Care Units in a Tunisian Hospital

Carbapenem-resistant Acinetobacter baumannii (CRAB) strains can cause severe and difficult-to-treat infections in patients with compromised general health. CRAB strains disseminate rapidly in nosocomial settings by patient-to-patient contact, through medical devices and inanimate reservoirs. The occurrence of CRAB in patients residing in the intensive care units (ICUs) of the Sahloul University hospital in Sousse, Tunisia is high. The objective of the current study was to determine whether the surfaces of items present in five ICU wards and the medical personnel there operating could serve as reservoirs for CRAB strains. Furthermore, CRAB isolates from patients residing in the ICUs during the sampling campaign were analyzed for genome comparison with isolates from the ICUs environment. Overall, 206 items were screened for CRAB presence and 27 (14%) were contaminated with a CRAB isolate. The items were located in several areas of three ICUs. Eight of the 54 (15%) screened people working in the wards were colonized by CRAB on the hands. Patients residing in the ICUs were infected with CRAB strains sharing extensive genomic similarity with strains recovered in the nosocomial environment. The strains belonged to three sub-clades of the internationally disseminated clone (ST2). A clone emerging in the Mediterranean basin (ST85) was detected as well. The strains were OXA-23 or NDM-1 producers and were also pan-aminoglycoside resistant due to the presence of the armA gene. Hygiene measures are urgent to be implemented in the Sahloul hospital to avoid further spread of difficult-to-treat CRAB strains and preserve health of patients and personnel operating in the ICU wards.

Excess mortality and long-term disability from healthcare-associated carbapenem-resistant Acinetobacter baumannii infections: A nationwide population-based matched cohort study

BACKGROUND

Carbapenem resistance is perceived as a clinical challenge in the management of debilitated and immunocompromised patients who eventually will die from underlying diseases. We aimed to examine whether carbapenem resistance per se, rather than the underlying diseases, negatively affect outcomes, by comparing the excess mortality and morbidity from healthcare-associated infections (HAIs) caused by carbapenem-resistant Acinetobacter baumannii (CRAB) and carbapenem-susceptible A. baumannii (CSAB).

METHODS

This was a nationwide retrospective matched cohort study of hospitalized patients in 96 hospitals which participated in Taiwan Nosocomial Infection Surveillance (TNIS). A total of 2,213 patients with A. baumannii HAIs were individually matched to 4,426 patients without HAIs. Main outcomes were excess risks for one-year all-cause mortality and one-year new-onset chronic ventilator dependence or dialysis-dependent end-stage renal disease.

RESULTS

Excess one-year mortality was 27.2% in CRAB patients, compared with their matched uninfected inpatients, as well as 15.4% in CSAB patients (also compared with their matched uninfected inpatients), resulting in an attributable mortality of 11.8% (P <0.001) associated with carbapenem resistance. The excess risk associated with carbapenem resistance for new-onset chronic ventilator dependence was 5.2% (P <0.001). Carbapenem resistance was also associated with an extra cost of $2,511 per case of A. baumannii HAIs (P <0.001).

CONCLUSION

Carbapenem resistance is associated with a significant disease burden in terms of excess mortality, long-term ventilator dependence, and medical cost. Further studies on effects of antimicrobial stewardship programs in decreasing this burden are warranted.

Global Risk Maps of Climate Change Impacts on the Distribution of Acinetobacter baumannii Using GIS

Impacts of climate change rank among the century's most significant ecological and medical concerns. As a result of climatic changes, the distribution of some bacterial species will alter across time and space. Numerous bacterial infections will reorganize as a result worldwide. Acinetobacter baumannii Bouvet and Grimont is one of the most significant and frequently occurring bacteria identified in soil and air. The COVID-19 pandemic has changed how bacteriologists perceive this species as a new threat to human health. In order to estimate the existing and future worldwide distribution of A. baumannii under various climate change scenarios, about 1000 A. baumannii occurrence records were employed. Given its superior accuracy and dependability versus alternative modeling techniques, maximum entropy implemented in MaxEnt was selected as the modeling tool. The bioclimatic variable that contributes the most to the distribution of A. baumannii is the mean temperature of the coldest quarter (bio_11). The created current distribution model agreed with the species' actual globally dispersed distribution. It is projected that A. baumannii will experience a severe range expansion due to the increase in temperature brought on by global warming in different regions of its range. According to the risk maps created for 2050 and 2070 using two alternative RCPs, there are various regions that will be under risk of this bacterium as a result of rising temperature. Future data science and GIS evaluation of the current results are necessary, especially on a local level.

First Detection of Acinetobacter baumannii in Pediculus humanus capitis from Latin America

Several studies have documented the presence of Acinetobacter baumannii, a known multi-drug-resistant pathogen, in the human head louse, Pediculus humanus capitis. Since no reports from countries in Latin America have been published, the aim of the present study was to determine whether A. baumannii was present in head lice specimens collected in this geographic region. Head lice specimens from Argentina, Colombia, and Honduras were analyzed. PCR assays were performed to confirm the specimens' species and to investigate whether the DNA of A. baumannii was present. The products of the latter were sequenced to confirm bacterial identity. Altogether, 122 pools of head lice were analyzed, of which two (1.64%) were positive for A. baumannii's DNA. The positive head lice had been collected at the poorest study site in Honduras. The remaining specimens were negative. This study is the first to report the presence of A. baumannii in human head lice from Latin America. Further investigations are required to elucidate whether these ectoparasites can serve as natural reservoirs or even effectively transmit A. baumannii to humans.

Changing epidemiology and prognosis of nosocomial bloodstream infection: A single-center retrospective study in Taiwan

BACKGROUND

Nosocomial bloodstream infection (BSI) remains a significant cause of mortality and morbidity. We evaluate the trend of the pathogens of nosocomial BSI and investigate the distribution of the pathogens to demonstrate the risk factors of mortality.

METHODS

In this retrospective study, we collected data from a 2076-bed tertiary referral center that offers a full range of clinical services in central Taiwan during January, 2016 to December, 2017.

RESULTS

Five hundred and eighty-four patients were identified with nosocomial BSI. Among the comorbidities of nosocomial BSI patients with, the most frequent were hypertension, in 294 patients (50.3%), malignancy, in 279 patients (47.8%); diabetes, in 278 patients (47.6%); chronic kidney disease, in 171 patients (29.3%); and liver cirrhosis, in 132 patients (22.6%). Gram-positive organisms caused 22.9% of these nosocomial BSIs, gram-negative organisms caused 69.2%, and fungi caused 6.8%. The most common organism causing nosocomial BSIs were Klebsiella spp. (14%), E coli. (14%), and Enterococcus spp. (11%). Multivariate analysis of risk factors for mortality displayed that comorbidity with low body weight, liver cirrhosis, and malignancy, high CRP level, high Charlson Comorbidity Index and internal medicine and hematology/oncology distribution were strikingly associated with mortality (P = 0.0222, 0.0352, 0.0008, 0.0122, <0.001, and 0.041; [OR] = 1.8097, 1.9268, 2.7156, 2.7585, 3.5431, and 2.2449, respectively).

CONCLUSION

K. spp. and E coli. became the most common pathogens of nosocomial BSI in recent years. Comorbidities could be important roles to predictive the outcome of nosocomial BSI. The modifiable risk factors of nosocomial BSI may be investigated further to improve the outcome.

Acinetobacter baumannii among Patients Receiving Glucocorticoid Aerosol Therapy during Invasive Mechanical Ventilation, China

Acinetobacter baumannii is a nosocomial pathogen associated with severe illness and death. Glucocorticoid aerosol is a common inhalation therapy in patients receiving invasive mechanical ventilation. We conducted a prospective cohort study to analyze the association between glucocorticoid aerosol therapy and A. baumannii isolation from ventilator patients in China. Of 497 enrolled patients, 262 (52.7%) received glucocorticoid aerosol, and A. baumannii was isolated from 159 (32.0%). Glucocorticoid aerosol therapy was an independent risk factor for A. baumannii isolation (hazard ratio 1.5, 95% CI 1.02-2.28; p = 0.038). Patients receiving glucocorticoid aerosol had a higher cumulative hazard for A. baumannii isolation and analysis showed that glucocorticoid aerosol therapy increased A. baumannii isolation in most subpopulations. Glucocorticoid aerosol was not a direct risk factor for 30-day mortality, but A. baumannii isolation was independently associated with 30-day mortality in ventilator patients. Physicians should consider potential A. baumannii infection when prescribing glucocorticoid aerosol therapy.

Acinetobacter baumannii Infection-Related Mortality in Hospitalized Patients: Risk Factors and Potential Targets for Clinical and Antimicrobial Stewardship Interventions

Due to resistance and scarcity of treatment options, nosocomial Acinetobacter baumannii infections are associated with significant fatality rates. We investigated the factors contributing to infection-related deaths to develop tailored stewardship interventions that could reduce these high mortality rates. We reviewed the medical records of adult inpatients with A. baumannii infections over two years. Patient demographics and clinical data were collected and statistically analyzed. The study included 321 patients with positive A. baumannii microbiological cultures, with respiratory infections accounting for 58.6%, soft tissues 29.3%, bacteremia 8.6%, urine 2.1%, and others 1.4%. The study population’s median (IQR) age was 62.6 (38.9−94.9) years, and hospital stay was 20 (9.5−40) days. Statistical analysis revealed that various risk factors contribute significantly to high in-hospital all-cause mortality (44%), as well as 14-day and 28-day mortality rates. Deaths increased by a factor of 1.04 with every additional year of age (p = 0.000), admission to the critical care unit (p = 0.000, OR: 2.86), and patients admitted with an infectious diagnosis had nearly three times the mortality rate as those admitted with other diagnoses (p = 0.000, OR: 3.12). Male gender (p < 0.001, OR: 2.14), any comorbid conditions (p = 0.000, OR: 5.29), prolonged hospitalization (>7 days) (p = 0.023, OR: 1.98), and hospital acquisition of infection (p = 0.027, OR: 1.68) were among the most significant predictors of mortality. All variables were investigated for their impact on all-cause, 14-day, and 28-day mortality rates. Improving multidisciplinary infection control practices, regular disinfection of patient care equipment, and optimal intubation practice that avoids unnecessary intubation are necessary interventions to reduce infection-related mortality rates. Better antibiotic selection and de-escalation, shorter hospital stays whenever possible, prompt medical stabilization of comorbid conditions, and fewer unnecessary admissions to critical care units will all lead to improved outcomes.

Predictors of survival from Acinetobacter in Saudi Arabian intensive care units: A prospective, one-year, six-city, ten-center cohort study

BACKGROUND

Antibiotic-resistant Acinetobacter baumannii is a continuously-emerging worldwide health crisis, with mortality rates approaching 50% in intensive care unit (ICU) patients. The objective of this study was to evaluate regional, patient-related, and organism-related predictors of survival among critically-ill patients with confirmed Acinetobacter infection.

METHODS

This prospective cohort study was conducted within ten ICUs across six geographically- and climatologically-distinct cities across Saudi Arabia over 13 months.

RESULTS

Of 169 patients with confirmed Acinetobacter infection enrolled in the study, 80 (47.6%) died. Survivors were statistically younger, predominantly male, more likely to be admitted for trauma, less likely to have hypertension, diabetes, or have undergone hemodialysis, and more likely to have been treated with antibiotics prior to having a positive culture for Acinetobacter, but less likely to have received an aminoglycoside. Survivors also had lower baseline APACHE II and SOFA scores and were infected with stains of Acinetobacter that had less meropenem- or colistin-resistance. Multivariate analysis identified the following independent predictors of survival: younger age, lower ICU-day#1 APACHE-II and ICU-day#3 SOFA scores, being admitted for trauma, and having no history of hemodialysis.

CONCLUSIONS

Patient-related factors outweigh regional and hospital-related factors as predictors of survival among critically-ill patients with Acinetobacter infection.

Evidence of Antimicrobial Resistance from Maternity Units and Labor Rooms: A Water, Sanitation, and Hygiene (WASH) Study from Gujarat, India

The main objective of this study was to determine the microbial contamination and antimicrobial resistance pattern among isolated bacteria from the environment surfaces of maternity units and labor rooms of healthcare facilities in the Gujarat state of India. The cross-sectional study was conducted in ten healthcare facilities, where the microbiological swab samples were collected from various pre-decided environmental surfaces of the maternity and labor rooms as part of the Water, Sanitation and Hygiene (WASH) assessment. The swabs were analyzed by conventional microbiological culture methods to identify microorganisms, including antimicrobial susceptibility testing. The study provides an insight into the microbial contamination of the visibly clean areas, i.e., the maternity ward, labor room, and general wards of the healthcare facilities. The labor rooms were found to be highly contaminated in comparison to other selected sites. The microbiological findings revealed a predominance of Gram-negative bacteria, specifically Pseudomonas species. The antibiotic susceptibility testing indicates resistance against many commonly used antibiotics. This study produces an identified necessity for enhancing microbiological surveillance in labor rooms and maternity units. This study also highlights the importance of microbiological status along with the WASH status of healthcare facilities.

Incidence, outcomes, and predictors of Acinetobacter infection in Saudi Arabian critical care units

BACKGROUND

Acinetobacter is an increasingly-problematic organism, especially in intensive care units (ICUs). In this study, we compared its incidence, outcomes, and predictors spanning eight ICUs in five geographically and climatologically-diverse cities in Saudi Arabia.

METHODS

Geographic, climatologic, hospital-related, and patient-related factors were collected prospectively on 3179 patients admitted to eight Saudi ICUs from June 2018 through June 2019. These data then underwent both bivariable and multivariable analysis, the latter vis hierarchical logistic regression to identify predictors of clinically-manifest Acinetobacter infection.

RESULTS

Overall incidence of Acinetobacter infection was 3.9% (n = 124). Of these 124 infections, 122 (98.4%) were cultured as A. baumannii. Incidence ranged from 1.0 to 7.9% across the eight ICUs. On bivariable analysis, incident Acinetobacter infection was more common in university and military hospitals, in hospitals with more total beds and ICU isolation rooms, and in 2018 versus 2019, incidence steadily declining over the 13 study months. Mechanically-ventilated patients had ten-fold increased odds of infection. Adjusted (multivariable) analysis revealed the risk of clinically-manifest Acinetobacter infection to increase the longer patients were on mechanical ventilation. Increased risk also existed at certain hospitals over others, especially in university-affiliated and military hospitals, larger hospitals with more isolation rooms, and hospitals with fewer ICU beds.

CONCLUSION

In our study of eight ICUs across Saudi Arabia, inter-hospital differences did appear to account for inter-hospital differences in Acinetobacter incidence rates. Patients requiring mechanical ventilation for longer periods of time were particularly at risk.

Acinetobacter baumannii Infections in Times of COVID-19 Pandemic

The COVID-19 pandemic has generated an overuse of antimicrobials in critically ill patients. Acinetobacter baumannii frequently causes nosocomial infections, particularly in intensive care units (ICUs), where the incidence has increased over time. Since the WHO declared the COVID-19 pandemic on 12 March 2020, the disease has spread rapidly, and many of the patients infected with SARS-CoV-2 needed to be admitted to the ICU. Bacterial co-pathogens are commonly identified in viral respiratory infections and are important causes of morbidity and mortality. However, we cannot neglect the increased incidence of antimicrobial resistance, which may be attributed to the excess use of antimicrobial agents during the COVID-19 pandemic. Patients with COVID-19 could be vulnerable to other infections owing to multiple comorbidities with severe COVID-19, prolonged hospitalization, and SARS-CoV-2-associated immune dysfunction. These patients have acquired secondary bacterial infections or superinfections, mainly bacteremia and urinary tract infections. This review will summarize the prevalence of A. baumannii coinfection and secondary infection in patients with COVID-19.

Risk Factors of Multidrug Resistant Pathogens Induced Infection in Severe Acute Pancreatitis

Purpose:

A retrospective study was first performed to assess the multidrug resistant (MDR) pathogen in severe acute pancreatitis (SAP) patients who were treated using the step-up approach. We aim to assess the risk factors between MDR pathogen and potential covariates in SAP patients.

Methods:

The clinical data of 51 SAP patients who were treated from June, 2013 to December, 2016 were retrospectively collected. A total of 23 patients in the MDR group and 28 patients in the non-MDR group were reviewed. The risk factors for MDR pathogen-induced infections in SAP patients were analyzed.

Results:

Hyperlipidemia was the leading cause of SAP in our study. The mean duration of hospital stay was significantly longer in the patients with MDR pathogen infections (P=0.0135). The hospitalization expenses of MDR group were much higher than those in non-MDR group. The mortality of MDR group (56.5%) was higher than that in non-MDR group (28.6%) (P=0.0436). Gram-negative isolates (63.8%) were commonly detected in SAP patients. Acinetobacter baumannii was the most common MDR pathogens. Systemic disease (P = 0.0136), initial use of carbapenem (P = 0.0438), and open necrosectomy (P = 0.0002) were the potential risk factors for MDR pathogen-induced infections in SAP. Furthermore, the logistic regression analysis revealed that open necrosectomy was the independent variable for MDR infections (OR: 15.6, 95% CI: 2.951–82.469, P = 0.0012).

Conclusions:

MDR pathogen-induced infections were common in SAP patients and Acinetobacter baumannii was the main pathogen. Meanwhile, open necrosectomy was the independent risk factor for the infection of MDR pathogen.

Multidrug-resistant Acinetobacter baumannii outbreaks: a global problem in healthcare settings

INTRODUCTION

The increase in the prevalence of multidrug-resistant Acinetobacter baumannii infections in hospital settings has rapidly emerged worldwide as a serious health problem.

METHODS

This review synthetizes the epidemiology of multidrug-resistant A. baumannii, highlighting resistance mechanisms.

CONCLUSIONS

Understanding the genetic mechanisms of resistance as well as the associated risk factors is critical to develop and implement adequate measures to control and prevent acquisition of nosocomial infections, especially in an intensive care unit setting.

Development and Validation of a Model for Predicting the Risk of Death in Patients with Acinetobacter baumannii Infection: A Retrospective Study

Purpose

This study aimed to develop and validate a personalized prediction model of death risk in patients with Acinetobacter baumannii (A. baumannii) infection and thus guide clinical research and support clinical decision-making.

Patients and Methods

The development group is comprised of 350 patients with A. baumannii infection admitted between January 2013 and December 2015 in The First Affiliated Hospital of Anhui Medical University. Further, 272 patients in the validation group were admitted between January 2016 and December 2018. The univariate and multivariate logistic regression analyses were used to determine the independent risk factors for death with A. baumannii infection. The nomogram prediction model was established based on the regression coefficients. The discrimination of the proposed prediction model was evaluated using the area under the curve (AUC) of the receiver operating characteristic (ROC) curves and decision curve analysis (DCA). The calibration diagram was used to evaluate the calibration degree of this model.

Results

The infectious source, carbapenem-resistant A. baumannii (CRAB), hypoalbuminemia, Charlson comorbidity index (CCI), and mechanical ventilation (MV) were independent risk factors for death. The AUC of the ROC curve of the two groups was 0.768 and 0.792, respectively. The net income was higher when the probability was between 30% and 80%, showing a strong discrimination capacity of the proposed model. The calibration curve swung around the 45° oblique line, indicating a high degree of calibration.

Conclusion

The proposed model helped predict the risk of death from A. baumannii infection, improve the early identification of patients with a higher risk of death, and guide clinical treatment.

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Risk factors associated with bloodstream infection among patients colonized by multidrug-resistant Acinetobacter baumannii: A 7-year observational study in a general hospital

We studied bloodstream infection by multidrug-resistant Acinetobacter baumannii among patients in a medical intensive care unit. Over a 7-year period, 47 of 441 colonized patients developed a bloodstream infection.. Endotracheal intubation (odds ratio [OR], 5.88), ventilator support (OR, 3.70), and central venous catheterization (OR, 3.48) were identified as risk factors.

Prevalence and Outcomes of Infection Among Patients in Intensive Care Units in 2017

IMPORTANCE

Infection is frequent among patients in the intensive care unit (ICU). Contemporary information about the types of infections, causative pathogens, and outcomes can aid the development of policies for prevention, diagnosis, treatment, and resource allocation and may assist in the design of interventional studies.

OBJECTIVE

To provide information about the prevalence and outcomes of infection and the available resources in ICUs worldwide.

DESIGN, SETTING, AND PARTICIPANTS

Observational 24-hour point prevalence study with longitudinal follow-up at 1150 centers in 88 countries. All adult patients (aged ≥18 years) treated at a participating ICU during a 24-hour period commencing at 08:00 on September 13, 2017, were included. The final follow-up date was November 13, 2017.

EXPOSURES

Infection diagnosis and receipt of antibiotics.

MAIN OUTCOMES AND MEASURES

Prevalence of infection and antibiotic exposure (cross-sectional design) and all-cause in-hospital mortality (longitudinal design).

RESULTS

Among 15 202 included patients (mean age, 61.1 years [SD, 17.3 years]; 9181 were men [60.4%]), infection data were available for 15 165 (99.8%); 8135 (54%) had suspected or proven infection, including 1760 (22%) with ICU-acquired infection. A total of 10 640 patients (70%) received at least 1 antibiotic. The proportion of patients with suspected or proven infection ranged from 43% (141/328) in Australasia to 60% (1892/3150) in Asia and the Middle East. Among the 8135 patients with suspected or proven infection, 5259 (65%) had at least 1 positive microbiological culture; gram-negative microorganisms were identified in 67% of these patients (n = 3540), gram-positive microorganisms in 37% (n = 1946), and fungal microorganisms in 16% (n = 864). The in-hospital mortality rate was 30% (2404/7936) in patients with suspected or proven infection. In a multilevel analysis, ICU-acquired infection was independently associated with higher risk of mortality compared with community-acquired infection (odds ratio [OR], 1.32 [95% CI, 1.10-1.60]; P = .003). Among antibiotic-resistant microorganisms, infection with vancomycin-resistant Enterococcus (OR, 2.41 [95% CI, 1.43-4.06]; P = .001), Klebsiella resistant to β-lactam antibiotics, including third-generation cephalosporins and carbapenems (OR, 1.29 [95% CI, 1.02-1.63]; P = .03), or carbapenem-resistant Acinetobacter species (OR, 1.40 [95% CI, 1.08-1.81]; P = .01) was independently associated with a higher risk of death vs infection with another microorganism.

CONCLUSIONS AND RELEVANCE

In a worldwide sample of patients admitted to ICUs in September 2017, the prevalence of suspected or proven infection was high, with a substantial risk of in-hospital mortality.

Assessment of Molecular Mechanism of Gallate-Polyvinylpyrrolidone-Capped Hybrid Silver Nanoparticles against Carbapenem-Resistant Acinetobacter baumannii

Acinetobacter baumannii is an opportunistic nosocomial pathogen and causes bacteremia, urinary tract infections, meningitis, and pneumonia. The emergence of drug-resistant strain makes most of the current antibiotics ineffective. It is high time to screen some therapeutics against drug-resistant strains. Plant-based medicines have recently emerged as one of the important therapeutic choices. Therefore, in the present study, we have screened the metabolites of Phyllanthus emblica, Ocimum tenuiflorum, and Murraya koenigii for their antibacterial effect against carabapenem-resistant strain (RS-307) of A. baumannii. The result showed that the methanolic extract of P. emblica inhibits the growth of RS-307. The composition of this extract was determined using phytochemical screening and nuclear magnetic resonance (1D and 2D-NMR). The mechanism of action of the plant extract was validated by estimating reactive oxygen species (ROS), lipid peroxidation, protein carbonylation, and membrane damage. The result showed that treatment with this extract showed a significant elevation in the production of ROS generations, lipid peroxidation, and protein carbonylation. This confirms that plant extract treatment confirmed ROS-dependent membrane damage mechanism. The NMR result showed the presence of ethyl gallate, ellagic acid, chebulagic acid, quercetin, flavonoid, and alkaloid. To validate the antimicrobial activity of the secondary metabolite (i.e., gallic acid), we synthesized gallate-polyvinylpyrrolidone-capped hybrid silver nanoparticles (G-PVP-AgNPs) and characterized using Fourier transform infrared spectroscopy (FTIR). G-PVP-AgNPs showed good antimicrobial activity against RS-307, and its mechanism of action was investigated using fluorescence and transmission electron microscopy and FTIR that confirmed ROS-dependent killing mechanism. Therefore, the present study highlighted and recommended the use of G-PVP-AgNPs as suitable therapeutics against carbapenem-resistant A. baumannii.

Risk factors for acquisition and mortality of multidrug-resistant Acinetobacter baumannii bacteremia: A retrospective study from a Chinese hospital

Bloodstream infection caused by Acinetobacter baumannii has become a major clinical concern, especially multidrug-resistant A baumannii (MDRAB). The aim of this study was to identify the risk factors of nosocomial acquired MDRAB bacteremia and to determine the risk factors related to the mortality of patients with MDRAB bacteremia. Patients with nosocomial acquired A baumannii bacteremia were enrolled between January, 2013 and December, 2017 at the First Affiliated Hospital, School of Medicine, Zhejiang University. Medical records were reviewed, and the clinical and microbial characteristics were collected. Among the 338 patients suffering from A baumannii bacteremia, 274 patients were infected with MDRAB bacteremia. Bacteremia-related mortality was 46.4% for the overall sample; 56.2% for MDRAB bacteremia patients, 4.7% for non-MDRAB bacteremia patients. The identified risk factors for developing MDRAB bacteremia were previous exposure to carbapenems [odds ratio (OR) 5.78, P = .005] and penicillins+β-lactamase inhibitors (OR 4.29, P = .009). Primary bacteremia tended to develop non-MDR bacteremia (OR 0.10, P = .002). The risk factors for MDRAB bacteremia-related mortality were old age (OR 1.02, P = .036), a high Pitt bacteremia score (OR 1.32, P < .001), bacteremia occurring after severe pneumonia (OR 8.66, P < .001), while catheter-related infection (OR 0.47, P = .049) and operations for treating infection (OR 0.51, P = .043) may have a better outcome. Patients with MDRAB had a higher mortality rate. Patients with previous carbapenems and penicillins+β-lactamase inhibitor exposure are at an increased risk of MDRAB bacteremia, whereas patients with primary bacteremia tended to develop non-MDR bacteremia. The risk factors for MDRAB bacteremia-related mortality were old age, a high Pitt bacteremia score, and bacteremia occurring after severe pneumonia, whereas catheter-related infection and operations for the treatment of infection may have a better outcome.

A Case-Control Study: Clinical Characteristics of Nosocomial Bloodstream Infections Versus Non-bloodstream Infections of Acinetobacter spp

Background

Acinetobacter spp. are among the most common causes of bacterial nosocomial infections, including pneumonia and bloodstream infections. Previous studies on the risk factors of bloodstream Acinetobacter spp. infections (BSAcIs) primarily compared uninfected patients to those with BSAcIs. However, the identified risk factors contribute to either BSIs or Acinetobacter spp. infections. To the best of our knowledge, this is the first study to analyze the risk factors of BSAcIs in comparison to non-bloodstream Acinetobacter infections (non-BSAcIs).

Methods

We retrospectively reviewed 10 years of medical records of BSAcIs from a teaching hospital in Shanghai. Clinical characteristics and treatment outcomes were compared between BSAcIs and non-BSAcIs. Treatment outcomes of carbapenem- and sulbactam-based regimens were also evaluated.

Results

Respiratory tract infections (43.1%, 44/102) were the most common source of BSAcIs. The in-hospital mortality rate of BSAcIs (22.5%, 23/102) was significantly higher than that of non-BSAcIs (10.8%, 24/204). Compared with non-BSAcIs, the previous use of corticoids, proton pump inhibitor (PPI) usage, and the implementation of intracranial drainage were independent risk factors for BSAcIs. The clinical efficacy rate of antimicrobial treatment of carbapenem-susceptible BSAcIs was significantly higher than that of carbapenem-non-susceptible (CNS) BSAcIs (74.0% vs 44.3%). Sulbactam-based regimens had similar clinical efficacy rates as carbapenem-based regimens for treating CNS-BSAcIs (50.0% vs 45.8%).

Conclusions

The in-hospital mortality rate of BSAcIs was significantly higher than that of non-BSAcIs. Glucocorticoids, PPI usage, and intracranial drainage were independent risk factors for BSAcIs. Sulbactam-based regimens had similar clinical efficacy rates as carbapenem-based regimens for treating CNS-BSAcIs.

Rationale and design of an inhibitor of RecA protein as an inhibitor of Acinetobacter baumannii

Acinetobacter baumannii is one of the ESKAPE pathogen, which causes pneumonia, urinary tract infections, and is linked to high degree of morbidity and mortality. One-way antibiotic and disinfectant resistance is acquired by the activation of RecA-mediated DNA repair (SOS-response) that maintain ROS-dependent DNA damage caused by these anti-bacterial molecules. To increase the efficacy of different anti-microbial, there is a need to design an inhibitor against RecA of A. baumannii. We have performed homology modeling to generate the structure of RecA, followed by model refinement and validation. High-throughput virtual screening of 1,80,313 primary and secondary metabolites against RecA was performed in HTVS, SP, and XP docking modes. The selected 195 compounds were further analyzed for binding free energy by molecular mechanics approach. The selected top two molecules from molecular mechanics approach were further validated by molecular dynamics simulation (MDS). In-silico high-throughput virtual screening and MDS validation identified ZINC01530654 or  (+-)-2-((4-((7-Chloro-4-quinolyl)amino)pentyl)ethylamino)ethanol sulfate (or hydroxychloroquine sulfate) as a possible lead molecule binding to RecA protein. We have experimentally determined the mechanism of ZINC01530654 to RecA protein. These findings suggest a strategy to chemically inhibit the vital process controlled by RecA that could be helpful for the development of new antibacterial agents.

Bacteremic and non-bacteremic pneumonia caused by Acinetobacter baumannii in ICUs of South China: A Clinical and Microbiological Study

Acinetobacter baumannii has been a dreadful problem for ICU physicians for a long time. Bacteremic pneumonia (BP) caused by this organism has a higher mortality compared to other organisms. Between 2012 and 2015, 86 BP and 89 non-bacteremic pneumonia (NBP) patients from five ICUs were enrolled into the study. The 7-day and 14-day mortality rates were higher in BP patients than in NBP patients (P < 0.001). Procalcitonin elevation, high APACHEII score and recent surgery, were independently associated with BP episodes. Acute respiratory distress syndrome, coma, high APACHEII score and procalcitonin elevation, were independently associated with mortality in the BP group. Extensively drug-resistant isolates were detected in 34.9% of BP and 25.8% of NBP isolates. PFGE identified 12 and 9 genotypes in the BP and NBP isolates, respectively, with 6 genotypes shared by both groups. ST195 was the most prevalent type (40%), followed by ST457 (18.9%). The pandemic clonal complex 92 was predominant, accounting for 94.3% of the strains. For all studied periods, mortality remained higher in the BP than the NBP group. Disease severity was the main risk factor for high mortality in the BP group, and other factors related to mortality were infection, and not treatment or microbiology-related.

Incidence, risk factors, and outcome of multidrug-resistant Acinetobacter baumannii acquisition during an outbreak in a burns unit

BACKGROUND

Multidrug-resistant Acinetobacter baumannii (MR-AB) can cause outbreaks in a burns unit.

AIM

To study the incidence, risk factors and outcome of MR-AB colonization during an outbreak.

METHODS

A prospective study was conducted from April to November 2014 in a burns unit in Paris. Weekly surveillance cultures of patients and their environment were performed. MR-AB acquisition, discharge, or death without MR-AB colonization were considered as competing events. To identify risk factors for colonization, baseline characteristics and time-dependent variables were investigated in univariate and multivariate analyses using Cox models. MR-AB strains were genotypically compared using multi-locus sequence typing.

FINDINGS

Eighty-six patients were admitted in the burns unit during the study period. Among 77 patients without MR-AB colonization at admission, 25 (32%) acquired MR-AB with a cumulative incidence of 30% at 28 days (95% CI: 20-40). Median time to MR-AB acquisition was 13 days (range: 5-34). In multivariate analysis, risk factors for MR-AB acquisition were ≥2 skin graft procedures performed [hazard ratio (HR): 2.97; 95% confidence interval (CI): 1.10-8.00; P = 0.032] and antibiotic therapy during hospitalization (HR: 4.42; 95% CI: 1.19-16.4; P = 0.026). A major sequence type of MR-AB (ST2) was found in 94% and 92% of patients and environmental strains, respectively, with all strains harbouring the blaOXA-23 gene. MR-AB colonization increased length of hospitalization (HR: 0.32; 95% CI: 0.17-0.58; P = 0.0002) by a median of 12 days.

CONCLUSION

A high incidence of MR-AB acquisition was seen during this outbreak with most strains from patients and their environment belonging to single sequence type. MR-AB colonization was associated with more skin graft procedures, antibiotic use, and prolonged hospitalization.

Risk factors associated with multi-drug-resistant Acinetobacter baumannii nosocomial infections at a tertiary care hospital in Makkah, Saudi Arabia - a matched case-control study

Objective To determine risk factors for multi-drug-resistant Acinetobacter baumannii (MDR-AB) nosocomial infections in intensive care units in a tertiary care hospital, Makkah, Saudi Arabia. Methods We performed a hospital-based, matched case-control study in patients who were admitted to Al Noor Specialist Hospital between 1 January 2012 and 31 August 2012. The study included cases of A. baumannii nosocomial infection and controls without infection. Controls were matched to cases by age and ward of admission. Results The most frequent site of infection was the respiratory tract (77.3%). Susceptibility to antimicrobial MDR-AB was 92.0% for ceftazidime and ciprofloxacin, while it was 83.3% for imipenem, 83.0% for trimethoprim, 79.0% for amikacin, and 72.7% for gentamicin. Multiple logistic regression of risk factors showed that immunosuppression (OR = 2.9; 95% CI 1.5-5.6; p = 0.002), clinical outcome (OR = 0.4; 95% CI 0.3-0.9; p = 0.01), invasive procedures (OR = 7.9; 95% CI 1.8-34.2; p = 0.002), a central venous catheter (OR = 2.9; 95% CI 1.5-5.6; p = 0.000), and an endotracheal tube (OR = 3.4; 95% CI 1.6-7.3; p = 0.001) were associated with MDR-AB. Conclusions Acinetobacter nosocomial infections are associated with admission to the ICU (Intensive care unit) and exposure to invasive procedures.

Risk Factors, Clinical Presentation, and Outcome of Acinetobacter baumannii Bacteremia

Infections caused by Acinetobacter baumannii (AB), an increasingly prevalent nosocomial pathogen, have been associated with high morbidity and mortality. We conducted this study to analyze the clinical features, outcomes, and factors influencing the survival of patients with AB bacteremia. We retrospectively examined the medical records of all patients developing AB bacteremia during their hospital stay at a tertiary care hospital in Beirut between 2010 and 2015. Ninety episodes of AB bacteremia were documented in eighty-five patients. Univariate analysis showed that prior exposure to high dose steroids, diabetes mellitus, mechanical ventilation, prior use of colistin and tigecycline, presence of septic shock, and critical care unit stay were associated with a poor outcome. High dose steroids and presence of septic shock were significant on multivariate analysis. Crude mortality rate was 63.5%. 70.3% of the deaths were attributed to the bacteremia. On acquisition, 39 patients had septicemia. Despite high index of suspicion and initiation of colistin and/or tigecycline in 18/39 patients, a grim outcome could not be averted and 37 patients died within 2.16 days. Seven patients had transient benign bacteremia; three of which were treated with removal of the line. The remaining four did not receive any antibiotics due to withdrawal of care and died within 26.25 days of acquiring the bacteremia, with no signs of persistent infection on follow up. A prolonged hospital stay is frequently associated with loss of functionality, and steroid and antibiotic exposure. These factors seem to impact the mortality of AB bacteremia, a disease with high mortality rate and limited therapeutic options.

Biofilm Formation and Motility Depend on the Nature of the Acinetobacter baumannii Clinical Isolates

Acinetobacter baumannii is a nosocomial pathogen involved in various infections ranging from minor soft-tissue infections to more severe infections such as ventilator-associated pneumonia and bacteremia. The severity and the type of infections depend on the genetic and phenotypic variations of the strains. In this study, we compared the extent of biofilm formation and motility displayed by 60 multidrug-resistant A. baumannii clinical strains isolated from blood and sputum samples from patients from Southern India. Our results showed that isolates from the sputum samples formed significantly more robust biofilm compared to the blood isolates. On the other hand, we observed that the blood isolates were more motile than the sputum isolates. To the best of our knowledge, this is the first study that systematically evaluated the correlation between these two phenotypic traits and the nature of the isolates.

Clinical epidemiology and resistance mechanisms of carbapenem-resistant Acinetobacter baumannii, French Guiana, 2008-2014

This study investigated the clinical epidemiology and resistance mechanisms of Acinetobacter baumannii and characterised the clonal diversity of carbapenem-resistant A. baumannii (CRAB) during an ICU-associated outbreak at Cayenne Hospital, French Guiana. All non-duplicate A. baumannii isolates from 2008 to 2014 were tested for antibiotic susceptibility by disk diffusion. Multilocus sequence typing, pulsed-field gel electrophoresis (PFGE) and characterisation of carbapenemase-encoding genes were performed on CRAB. Of the 441 A. baumannii isolates, most were from males (54.0%) and were detected mainly from the ICU (30.8%) and medicine wards (21.8%). In the ICU, strains were mainly isolated from the respiratory tract (44.1%) and bloodstream (14.0%), whereas in medicine wards they mainly were from wound/drainage (36.5%) and bloodstream (25.0%). A. baumannii showed the greatest susceptibility to piperacillin/tazobactam (92.7%), imipenem (92.5%), colistin (95.6%) and amikacin (97.2%), being lower in the ICU and medicine wards compared with other wards. An outbreak of OXA-23-producing CRAB occurred in the 13-bed ICU in 2010. CRAB strains were more co-resistant to other antimicrobials compared with non-CRAB. Molecular genetics analysis revealed five sequence types [ST78, ST107 and ST642 and two new STs (ST830 and ST831)]. Analysis of PFGE profiles indicated cross-transmissions of CRAB within the ICU, between the ICU and one medicine ward during transfer of patients, and within that medicine ward. This study provides the first clinical and molecular data of A. baumannii from French Guiana and the Amazon basin. The ICU was the highest risk unit of this nosocomial outbreak of OXA-23-producing CRAB, which could subsequently disseminate within the hospital.

Clinical and economic outcomes of Acinetobacter vis a vis non-Acinetobacter infections in an Indian teaching hospital

Context:

Acinetobacter infections are a major nosocomial infection causing epidemics of infection in the Intensive Care Units (ICU).

Aims:

This study estimates the clinical and economic outcomes of Acinetobacter infections and compares them with those of non-Acinetobacter bacterial infections.

Settings and Design:

Prospective cross-sectional observational study carried out for 6 months in the medicine ICU of a tertiary care hospital.

Materials and Methods:

Patients were divided in two groups, one group with Acinetobacter infections and the other with non-Acinetobacter infections. The data was collected for infection, length of stay (LOS), mortality and cost along with patient demographics from the hospital records for analysis.

Statistical Analysis Used:

The data was analyzed using Statistical Package for the Social Sciences Version 15.0. The LOS and cost of treatment (COT) for the two groups were compared using the nonparametric Mann–Whitney U-test.

Results:

A total of 220 patients were studied out of which 91 had Acinetobacter infections. The median LOS was 20 days in Group-A and 12 days in Group-B (P < 0.0001). The median COT was INR 125,862 in Group-A and INR 68,228 in the Group-B (P < 0.0001). Mortality in Group-A and Group-B was 32.97 and 32.56 (P = 0.949) respectively.

Conclusion:

The burden of Acinetobacter infections in ICUs is increasing with the increase in LOS and COT for the patients. The infection control team has to play a major role in reducing the rate of nosocomial infections.

Risk Factors and Clinical Outcomes for Patients With Acinetobacter baumannii Bacteremia

Acinetobacter (A.) baumannii, an opportunistic nosocomial pathogen that can cause significant morbidity and mortality, has emerged as a worldwide problem. This study aimed to analyze the clinical features and outcomes of patients with A. baumannii bacteremia and determine the factors influencing survival by using 14-day mortality as the primary endpoint. A 6-year retrospective study of 122 cases with monomicrobial A. baumannii bacteremia was conducted in Chinese People's Liberation Army (PLA) General Hospital from January 2008 to April 2014. Predictors of 14-day mortality were identified by logistic regression analysis. The overall 14-day mortality rate was 40.2% (49 of 122 patients). Multivariable analysis revealed that independent predictors of 14-day mortality included severity of illness defined by Pitt Bacteremia Score (PBS) (odds ratio [OR], 0.46; 95% confidence interval [CI], 0.340-0.619; P < 0.001), neutropenia (OR, 18.02; 95% CI, 1.667-194.67; P = 0.017), and malignancy (OR, 4.63; 95% CI, 1.292-16.588; P = 0.019). The effect of malignancy was influenced by neutropenia (OR for interaction term, 1.60; 95% CI, 1.15-2.22; P = 0.005). A subgroup analysis revealed that 14-day mortality rate for patients with underlying hematological malignancies and solid tumors was 75% (12/16) and 40% (12/30), respectively. Survival analysis revealed that mortality in patients with hematological malignancies was higher than that in patients with solid tumors (P = 0.032). The outcomes of patients with A. baumannii bacteremia were related to PBS, neutropenia, and malignancy. Compared with solid tumors, patients with hematological malignancies had a higher mortality in the setting of A. baumannii bacteremia.

Screening of Herbal-Based Bioactive Extract Against Carbapenem-Resistant Strain of Acinetobacter baumannii

Acinetobacter baumannii is grouped in the ESKAPE pathogens by Infectious Disease Society of America, which is linked to high degree of morbidity, mortality, and increased costs. The high level of acquired and intrinsic resistance mechanisms of these bacteria makes it an urgent requirement to find a suitable alternative to carbapenem, a commonly prescribed drug for Acinetobacter infection. In this study, methanolic extracts of six medicinal plants were subjected to phytochemical screening and their antimicrobial activity was tested against two strains of A. baumannii (ATCC 19606, carbapenem-sensitive strain, and RS 307, carbapenem-resistant strain). Synergistic effect of the plant extracts and antibiotics was also tested. Bael or Aegle marmelos contains tannin, phenol, terpenoids, glycoside, alkaloids, coumarine, steroid, and quinones. Flowers of madar or Calotropis procera possess tannin, phenol, terpenoids, glycoside, quinone, anthraquinone, anthocyanin, coumarin, and steroid. An inhibitory growth curve was seen for both the bacterial strains when treated with A. marmelos, Curcuma longa, and leaves and flowers of C. procera. Antibiotics alone showed a small zone of inhibition, but when used with herbal extracts they exhibited larger zone of inhibition. Synergistic effect of A. marmelos and imipenem was the best against both the strains of A. baumannii. From this study, it can be concluded that extracts from A. marmelos and leaves and flowers of C. procera exhibited the most effective antibacterial activity. These herbal extracts may be used to screen the bioactive compound against the carbapenem-resistant strain of A. baumannii.

Impact of rapid identification of Acinetobacter Baumannii via matrix-assisted laser desorption ionization time-of-flight mass spectrometry combined with antimicrobial stewardship in patients with pneumonia and/or bacteremia

We evaluated the clinical and economic outcomes of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) with stewardship intervention in patients with Acinetobacter baumannii (AB) pneumonia and/or bacteremia. 66 patients were included in the pre-intervention group and 53 in the intervention group. The combination of AB identification via MALDI-TOF MS and ID PharmD intervention significantly reduced the median time to effective therapy compared to conventional identification without intervention [77.7 (95% CI: 73.1-84.8) to 36.6 (95% CI: 25.9-50.9) hours (P < 0.0001)]. Rapid organism identification along with ID PharmD intervention was also associated with a 19% increase in clinical cure (15% versus 34%, P = 0.016) and a decreased length of stay during antibiotic therapy (13 [8-18] versus 11 [7-15] days, P = 0.021). No difference in 14-day mortality was observed (20% versus 25%, P = 0.526). Median costs during infection were approximately $6500 less in the intervention group ($49,402 [35,307-86,566] versus $42,872 [26,966-74,506]; P = 0.243). AB identification via MALDI-TOF MS combined with stewardship intervention allows for timely, effective antimicrobial therapy and is associated with increased clinical cure.

Bloodstream infections in intensive care unit patients: distribution and antibiotic resistance of bacteria

Bloodstream infections (BSIs) are among the leading infections in critically ill patients. The case-fatality rate associated with BSIs in patients admitted to intensive care units (ICUs) reaches 35%–50%. The emergence and diffusion of bacteria with resistance to antibiotics is a global health problem. Multidrug-resistant bacteria were detected in 50.7% of patients with BSIs in a recently published international observational study, with methicillin resistance detected in 48% of Staphylococcus aureus strains, carbapenem resistance detected in 69% of Acinetobacter spp., in 38% of Klebsiella pneumoniae, and in 37% of Pseudomonas spp. Prior hospitalization and antibiotic exposure have been identified as risk factors for infections caused by resistant bacteria in different studies. Patients with BSIs caused by resistant strains showed an increased risk of mortality, which may be explained by a higher incidence of inappropriate empirical therapy in different studies. The molecular genetic characterization of resistant bacteria allows the understanding of the most common mechanisms underlying their resistance and the adoption of surveillance measures. Knowledge of epidemiology, risk factors, mechanisms of resistance, and outcomes of BSIs caused by resistant bacteria may have a major influence on global management of ICU patients. The aim of this review is to provide the clinician an update on BSIs caused by resistant bacteria in ICU patients.

Modeling the impact of interventions against Acinetobacter baumannii transmission in intensive care units

The efficacy of infection control interventions against Acinetobacter baumannii remains unclear, despite such information being critical for effective prevention of the transmission of this pathogen. Mathematical modeling offers an alternative to clinical trials, which may be prohibitively expensive, unfeasible or unethical, in predicting the impact of interventions. Furthermore, it allows the ability to ask key “what if” questions to evaluate which interventions have the most impact. We constructed a transmission dynamic model to quantify the effects of interventions on reducing A. baumannii prevalence and the basic reproduction ratio (R₀) in intensive care units (ICUs). We distinguished between colonization and infection, and incorporated antibiotic exposure and transmission from free-living bacteria in the environment. Under the assumptions and parameterization in our model, 25% and 18% of patients are colonized and infected with A. baumannii, respectively; and R₀ is 1.4. Improved compliance with hand hygiene (≥87%), enhanced environmental cleaning, reduced length of ICU stay of colonized patients (≤ 10 days), shorter durations of antibiotic treatment of A. baumannii (≤6 days), and isolation of infected patients combined with cleaning of isolation rooms are effective, reducing R₀ to below unity. In contrast, expediting the recovery of the intestinal microbiota (e.g. use of probiotics) is not effective. This study represents a biologically realistic model of the transmission dynamics of A. baumannii, and the most comprehensive analysis of the effectiveness of interventions against this pathogen. Our study provides important data for designing effective infection control interventions.

Long-term effectiveness of infection and antibiotic control programs on the transmission of carbapenem-resistant Acinetobacter calcoaceticus-Acinetobacter baumannii complex in central Taiwan

Objectives

A carbapenem-resistant Acinetobacter calcoaceticus-Acinetobacter baumannii complex (CRA complex) infection is one of most the difficult infections to control worldwide. We evaluated the long-term effects of infection control interventions on the incidence densities of healthcare-associated infection (HAI) and CRA complex infection, and the rates of Acinetobacter calcoaceticus-Acinetobacter baumannii complex bacteremia (AB).

Patients and methods

We performed a cross-sectional analysis at the Changhua Christian Hospital from January 2002 to December 2013. Interventions for infection control were implemented from 2002 to 2009 (period 1). From 2010 to 2013 (period 2), infection control programs were improved by in-service education and a hand hygiene campaign to prepare for international and national hospital accreditation. The effectiveness of infection and antibiotic control programs was assessed according to the incidence densities of HAI and CRA complex, rates of CRA complex and of AB, chlorhexidine consumption density, and defined daily dose of antibiotics.

Results

The incidence density of HAI decreased from 4.56‰ to 1.52‰ from periods 1 to 2 (P < 0.001). Likewise, the incidence of AB decreased from 177.79 to 137.76 per person-years per 100,000 admissions (P < 0.001). The incidence density of CRA complex ranged from 3.17–7.38‰. The chlorhexidine consumption density increased from 5.5 to 45.5 L per 1000 patient-days (P < 0.001). The consumption of piperacillin-tazobactam was lower in period 2 than in period 1 (P < 0.001).

Conclusion

Education for infection control programs, hand hygiene campaigns, and antibiotics control programs may decrease the incidence density of AB and HAI, and may help control CRA complex infection.

Impact of a bundle on prevention and control of healthcare associated infections in intensive care unit

Inpatients in the intensive care unit (ICU) are at high risk for healthcare-associated infections (HAIs). In the current study, a bundle of interventions and measures for preventing and controlling HAIs were developed and implemented in the ICU by trained personnel, and the impact of the bundle was evaluated. The incidence of HAIs, the adjusted daily incidence of HAIs and the incidence of three types of catheter-related infections before and after the bundle implementation were compared. The execution rate of the bundle for preventing and controlling ventilator-associated pneumonia (VAP) was increased from 82.06% in 2012 to 96.88% in 2013. The execution rate was increased from 83.03% in 2012 to 91.33% in 2013 for central line-associated bloodstream infection (CLABSI), from 87.00% to 94.40% for catheter-associated urinary tract infection (CAUTI), and from 82.05% to 98.55% for multidrug-resistant organisms (MDROs), respectively. In total, 136 cases (10.37%) in 2012 and 113 cases (7.72%) in 2013 involved HAIs, respectively. Patients suffered from infection of the lower respiratory tract, the most common site of HAIs, in 134 cases (79.29%) in 2012 and 107 cases (74.30%) in 2013 respectively. The incidence of VAP was 32.72‰ and 24.60‰, the number of strains of pathogens isolated was 198 and 173, and the number of MDROs detected in the ICU was 91 and 74 in 2012 and 2013, respectively. The percentage of MDROs among the pathogens causing HAIs was decreased in each quarter of 2013 as compared with the corresponding percentage in 2012. In 2013, the execution rate of the bundle for preventing and controlling HAIs was increased, whereas the incidence of HAIs and VAP decreased as compared with that in 2012.

Influence of ACB complex genospecies on clinical outcomes in a U.S. hospital with high rates of multidrug resistance

OBJECTIVES

Bacteria within the Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex commonly cause nosocomial infection and are often multidrug resistant. Advances in genospecies typing allow for speciation within the ACB complex; however, little is known about the effect of genospecies on patient outcomes.

METHODS

Adult patients with ACB complex bacteremia from Jan 2005-Oct 2012 were included. Bacterial isolates were speciated by rpoB gene sequence analysis, and clinical data were collected.

RESULTS

Of 147 patients with ACB complex bacteremia, 116 had A. baumannii (78.9%), 28 had Acinetobacter pittii (19.0%), and 3 had Acinetobacter nosocomialis (2.0%). A. baumannii bacteremia was associated with greater comorbidity and was more frequently multidrug resistant (79% vs. 16%, p < 0.01). Multidrug resistant A. baumannii but not susceptible A. baumannii was associated with worse outcomes compared to non-baumannii ACB complex bacteremia. Neither multidrug resistance nor genospecies was an independent predictor of mortality, but receipt of appropriate therapy was associated with decreased risk of mortality (OR, 0.13; 95% CI, 0.04-0.44; p < 0.01).

CONCLUSIONS

A. baumannii bacteremia is associated with worse clinical outcomes than non-baumannii ACB complex bacteremia. The difference, however, appears to be related to multidrug resistance and attendant receipt of appropriate therapy rather than genospecies.

Comparative analysis of surface-exposed virulence factors of Acinetobacter baumannii

Background

Acinetobacter baumannii is a significant hospital pathogen, particularly due to the dissemination of highly multidrug resistant isolates. Genome data have revealed that A. baumannii is highly genetically diverse, which correlates with major variations seen at the phenotypic level. Thus far, comparative genomic studies have been aimed at identifying resistance determinants in A. baumannii. In this study, we extend and expand on these analyses to gain greater insight into the virulence factors across eight A. baumannii strains which are clonally, temporally and geographically distinct, and includes an isolate considered non-pathogenic and a community-acquired A. baumannii.

Results

We have identified a large number of genes in the A. baumannii genomes that are known to play a role in virulence in other pathogens, such as the recently studied proline-alanine-alanine-arginine (PAAR)-repeat domains of the type VI secretion systems. Not surprising, many virulence candidates appear to be part of the A. baumannii core genome of virulent isolates but were often found to be insertionally disrupted in the avirulent A. baumannii strain SDF. Our study also reveals that many known or putative virulence determinants are restricted to specific clonal lineages, which suggests that these virulence determinants may be crucial for the success of these widespread common clones. It has previously been suggested that the high level of intrinsic and adaptive resistance has enabled the widespread presence of A. baumannii in the hospital environment. This appears to have facilitated the expansion of its repertoire of virulence traits, as in general, the nosocomial strains in this study possess more virulence genes compared to the community-acquired isolate.

Conclusions

Major genetic variation in known or putative virulence factors was seen across the eight strains included in this study, suggesting that virulence mechanisms are complex and multifaceted in A. baumannii. Overall, these analyses increase our understanding of A. baumannii pathogenicity and will assist in future studies determining the significance of virulence factors within clonal lineages and/or across the species.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-1020) contains supplementary material, which is available to authorized users.

Risk factors and outcomes of Stenotrophomonas maltophilia bacteraemia: a comparison with bacteraemia caused by Pseudomonas aeruginosa and Acinetobacter species

Stenotrophomonas maltophilia (SM) is an important nosocomial pathogen that exhibits intrinsic resistance to various antimicrobial agents. However, the risk factors for SM bacteraemia have not been sufficiently evaluated. From January 2005 to September 2012, we retrospectively compared the clinical backgrounds and outcomes of SM bacteraemic patients (SM group) with those of bacteraemic patients due to Pseudomonas aeruginosa (PA group) or Acinetobacter species (AC group). DNA genotyping of the SM isolates using the Diversilab system was performed to investigate the genetic relationships among the isolates. The SM, PA, and AC groups included 54, 167, and 69 patients, respectively. Nine of 17 patients in the SM group receiving trimethoprim-sulfamethoxazole prophylaxis developed SM bacteraemia. Independent risk factors for SM bacteraemia were the use of carbapenems and antipseudomonal cephalosporins and SM isolation within 30 days prior to the onset of bacteraemia. Earlier SM isolation was observed in 32 of 48 patients (66.7%) with SM bacteraemia who underwent clinical microbiological examinations. Of these 32 patients, 15 patients (46.9%) had the same focus of bacteraemia as was found in the previous isolation site. The 30-day all-cause mortality rate among the SM group (33.3%) was higher than that of the PA group (21.5%, p = 0.080) and the AC group (17.3%, p = 0.041). The independent factor that was associated with 30-day mortality was the SOFA score. DNA genotyping of SM isolates and epidemiological data suggested that no outbreak had occurred. SM bacteraemia was associated with high mortality and should be considered in patients with recent use of broad-spectrum antibiotics or in patients with recent isolation of the organism.

Risk factors and outcomes for patients with bloodstream infection due to Acinetobacter baumannii-calcoaceticus complex

Identifying patients at risk for bloodstream infection (BSI) due to Acinetobacter baumannii-Acinetobacter calcoaceticus complex (ABC) and providing early appropriate therapy are critical for improving patient outcomes. A retrospective matched case-control study was conducted to investigate the risk factors for BSI due to ABC in patients admitted to the Detroit Medical Center (DMC) between January 2006 and April 2009. The cases were patients with BSI due to ABC; the controls were patients not infected with ABC. Potential risk factors were collected 30 days prior to the ABC-positive culture date for the cases and 30 days prior to admission for the controls. A total of 245 case patients were matched with 245 control patients. Independent risk factors associated with BSI due to ABC included a Charlson's comorbidity score of ≥ 3 (odds ratio [OR], 2.34; P = 0.001), a direct admission from another health care facility (OR, 4.63; P < 0.0001), a prior hospitalization (OR, 3.11; P < 0.0001), the presence of an indwelling central venous line (OR, 2.75; P = 0.011), the receipt of total parenteral nutrition (OR, 21.2; P < 0.0001), the prior receipt of β-lactams (OR, 3.58; P < 0.0001), the prior receipt of carbapenems (OR, 3.18; P = 0.006), and the prior receipt of chemotherapy (OR, 15.42; P < 0.0001). The median time from the ABC-positive culture date to the initiation of the appropriate antimicrobial therapy was 2 days (interquartile range [IQR], 1 to 3 days). The in-hospital mortality rate was significantly higher among case patients than among control patients (OR, 3.40; P < 0.0001). BSIs due to ABC are more common among critically ill and debilitated institutionalized patients, who are heavily exposed to health care settings and invasive devices.