Incidence and predictors of 14-day mortality in multidrug-resistant Acinetobacter baumannii in ventilator-associated pneumonia

Epidemiology and mortality predictors for severe childhood community-acquired pneumonia in ICUs: A retrospective observational study

Background

To identify the epidemiology and mortality predictors of severe childhood community-acquired pneumonia (CAP) and evaluate the influence of medications on clinical outcomes in the real world.

Methods

We conducted a multicenter retrospective observational study among children aged ≤5 years with severe CAP, separately comparing the detailed information between those who experienced in-hospital death and those who survived in three different age groups. A multivariate logistic regression model was used to determine mortality predictors.

Results

A total of 945 children were recruited: 341 young children aged 2-59 months, 47 infants aged 29 days to 2 months, and 557 neonates aged less than 28 days. A total of 88 deaths occurred (9.3%). There was low adherence to antimicrobial guidelines in the group aged 2-59 months, and carbapenems widely served as initial empirical regimens. However, analysis of all three age groups showed that the efficacy of antibacterial drugs with initial empirical selection grades higher than those recommended by the guidelines was not better than that of antibacterial drugs with grades recommended by the guidelines. In multivariate analyses, very severe pneumonia (odds ratio (OR): 3.48; 95% confidence interval (CI): 1.36-8.93), lower birth weight (OR: 4.64; 95% CI: 1.78-12.20), severe underweight (OR: 6.06; 95% CI: 2.34-15.63), mechanical ventilation (OR: 2.58; 95% CI: 1.00-6.62; OR: 15.63; 95% CI 3.25-76.92), a higher number of comorbidities (OR: 8.40; 95% CI: 1.89-37.04), comorbidities including anemia (OR: 5.24; 95% CI: 2.33-11.76) and gastrointestinal hemorrhage (OR: 3.79; 95% CI: 1.36-10.53), and the use of sedative-hypnotics (OR: 2.60; 95% CI: 1.14-5.95) were independent risk factors for death; infants treated with probiotics had a lower mortality rate (OR: 0.14; 95% CI: 0.06-0.33).

Conclusions

Severe CAP remains a primary cause of death in children under 5 years of age. Clinical characteristics, comorbidities and medications are evidently associated with death. Importantly, we should pay particular attention to the identification of mortality predictors and establish prophylactic measures to reduce mortality.

Nosocomial Extracardiac Infections After Cardiac Surgery

Purpose of Review

Nosocomial extracardiac infections after cardiac surgery are a major public health issue affecting 3–8.2% of patients within 30–60 days following the intervention.

Recent Findings

Here, we have considered the most important postoperative infective complications that, in order of frequency, are pneumonia, surgical site infection, urinary tract infection, and bloodstream infection. The overall picture that emerges shows that they cause a greater perioperative morbidity and mortality with a longer hospitalization time and excess costs. Preventive interventions and corrective measures, diminishing the burden of nosocomial extracardiac infections, may reduce the global costs. A multidisciplinary team may assure a more appropriate management of nosocomial extracardiac infections leading to a reduction of hospitalization time and mortality rate.

Summary

The main and most current data on epidemiology, prevention, microbiology, diagnosis, and management for each one of the most important postoperative infective complications are reported. The establishment of an antimicrobial stewardship in each hospital seems to be, at the moment, the more valid strategy to counteract the challenging problems.

Clinical Features and Outcomes of Monobacterial and Polybacterial Episodes of Ventilator-Associated Pneumonia Due to Multidrug-Resistant Acinetobacter baumannii

Multidrug-resistant A. baumannii (MDRAB) VAP has high morbidity and mortality, and the rates are constantly increasing globally. Mono- and polybacterial MDRAB VAP might differ, including outcomes. We conducted a single-center, retrospective (January 2014−December 2016) study in the four ICUs (12−18−24 beds each) of a reference Lithuanian university hospital, aiming to compare the clinical features and the 30-day mortality of monobacterial and polybacterial MDRAB VAP episodes. A total of 156 MDRAB VAP episodes were analyzed: 105 (67.5%) were monomicrobial. The 30-day mortality was higher (p < 0.05) in monobacterial episodes: overall (57.1 vs. 37.3%), subgroup with appropriate antibiotic therapy (50.7 vs. 23.5%), and subgroup of XDR A. baumannii (57.3 vs. 36.4%). Monobacterial MDRAB VAP was associated (p < 0.05) with Charlson comorbidity index ≥3 (67.6 vs. 47.1%), respiratory comorbidities (19.0 vs. 5.9%), obesity (27.6 vs. 9.8%), prior hospitalization (58.1 vs. 31.4%), prior antibiotic therapy (99.0 vs. 92.2%), sepsis (88.6 vs. 76.5%), septic shock (51.9 vs. 34.6%), severe hypoxemia (23.8 vs. 7.8%), higher leukocyte count on VAP onset (median [IQR] 11.6 [8.4−16.6] vs. 10.9 [7.3−13.4]), and RRT need during ICU stay (37.1 vs. 17.6%). Patients with polybacterial VAP had a higher frequency of decreased level of consciousness (p < 0.05) on ICU admission (29.4 vs. 14.3%) and on VAP onset (29.4 vs. 11.4%). We concluded that monobacterial MDRAB VAP had different demographic/clinical characteristics compared to polybacterial and carried worse outcomes. These important findings need to be validated in a larger, prospective study, and the management implications to be further investigated.

Multidrug-Resistant Acinetobacter baumannii in Jordan

Background: Acinetobacter baumannii is a common cause of multi-drug (MDR)-resistant infections worldwide. The epidemiological and molecular characteristics of MDR-A. baumannii in Jordan is not known. Methods: A. baumannii isolates were collected from 2010 to 2020 from three tertiary hospitals in Jordan. Demographic and clinical data, isolates information, antibiotic susceptibility patterns, phenotypic, and molecular characterization of carbapenem resistance genes were performed. Results: A total of 622 A. baumannii isolates were collected during the study period. Most isolates were from males, aged 18−60 years, Jordanian, from infected wounds, and were patients in surgery or critical care units. Among patients from whom A. baumannii was isolated, associated risk factors for MDR were adults over 60, males, critically ill patients and infected wounds (OR 4.14, 2.45, 10, 7, respectively, p < 0.0001). Incidence rates from 2010 to 2015 showed a slight increase in MDR (3.75/1000 to 4.46/1000). Resistance patterns indicated high resistance for most cephalosporins, carbapenems, and fluoroquinolones, moderate resistance for trimethoprim/sulfamethoxazole and ampicillin/sulbactam, low resistance for aminoglycosides and tetracyclines, while colistin and tigecycline, have the lowest resistance rates. 76.8% of A. baumannii isolates were MDR and 99.2% were carbapenem-resistant. All isolates were positive for the OXA-51 gene (100%), 98.5% were positive for the OXA-23 gene, 26.6% for the VIM gene, while KPC and IMP genes were almost not detected (0% and 0.8% respectively). Conclusions: This is the first large, multicentric, prolonged study that provides insights into A. baumannii infections in Jordan. Attention to patients at higher risk is important for early identification. Colistin and tigecycline were the most effective antimicrobials.

Emerging Status of Multidrug-Resistant Bacteria and Fungi in the Arabian Peninsula

Simple Summary

The incidence and developing status of multidrug-resistant bacteria and fungi, as well as their related mortality, is reviewed by a systematic published literature search from nine countries in the Arabian Peninsula. In order to analyse the emerging status and mortality, a total of 382 research articles were selected from a comprehensive screening of 1705 papers. More than 850 deaths reported since 2010 in the Arabian Peninsula due to the infection of multidrug-resistant bacteria and fungi. Multidrug-resistant bacteria Acinetobacter baumannii, Mycobacterium tuberculosis, Staphylococcus aureus, and fungi Candida auris are the most prevalent and causing high deaths. To control these infections and associated deaths in the Arabian Peninsula, continuous preventive measures, accurate methods for early diagnosis of infection, active surveillance, constant monitoring, developing vaccines, eradicating multidrug resistance modulators, and data sharing among countries are required.

Abstract

We aimed to identify the prevalence and emerging status of multidrug-resistant bacteria and fungi and their associated mortality in nine countries in the Arabian Peninsula. Original research articles and case studies regarding multidrug-resistant bacteria and fungi in the Arabian Peninsula, published during the last 10 years, were retrieved from PubMed and Scopus. A total of 382 studies were included as per the inclusion and exclusion criteria, as well as the PRISMA guidelines, from a thorough screening of 1705 articles, in order to analyse the emerging status and mortality. The emerging nature of >120 multidrug-resistant (MDR) bacteria and fungi in the Arabian Peninsula is a serious concern that requires continuous monitoring and immediate preventive measures. More than 50% (n = 453) of multidrug-resistant, microbe-associated mortality (n = 871) in the Arabian Peninsula was due to MDR Acinetobacter baumannii, Mycobacterium tuberculosis and Staphylococcus aureus infection. Overall, a 16.51% mortality was reported among MDR-infected patients in the Arabian Peninsula from the 382 articles of this registered systematic review. MDR A. baumannii (5600 isolates) prevailed in all the nine countries of the Arabian Peninsula and was one of the fastest emerging MDR bacteria with the highest mortality (n = 210). A total of 13,087 Mycobacterium tuberculosis isolates were reported in the region. Candida auris (580 strains) is the most prevalent among the MDR fungal pathogen in the Arabian Peninsula, having caused 54 mortalities. Active surveillance, constant monitoring, the development of a candidate vaccine, an early diagnosis of MDR infection, the elimination of multidrug resistance modulators and uninterrupted preventive measures with enhanced data sharing are mandatory to control MDR infection and associated diseases of the Arabian Peninsula. Accurate and rapid detection methods are needed to differentiate MDR strain from other strains of the species. This review summarises the logical relation, prevalence, emerging status and associated mortality of MDR microbes in the Arabian Peninsula.

Phenotypic and genotypic characterisation of cephalosporin-, carbapenem- and colistin-resistant Gram-negative bacterial pathogens in Lebanon, Jordan and Iraq

Antimicrobial resistance (AMR) is a worldwide health concern that continues to escalate. A PubMed literature search identified articles from January 2015-August 2020 reviewing cephalosporin-, carbapenem- and colistin-resistant Gram-negative bacteria (GNB) in Lebanon, Jordan and Iraq, specifically focused on three main pathogens, namely Acinetobacter spp., Enterobacteriaceae (i.e. Escherichia coli and Klebsiella spp.) and Pseudomonas aeruginosa. Sixty-seven relevant articles published within the past 5 years highlighting trends in AMR in Lebanon, Jordan and Iraq were included. Increased resistance to carbapenems in Acinetobacter spp. isolates was observed in Lebanon, Jordan and Iraq; colistin resistance remained relatively low. Studies on Enterobacteriaceae isolates were more varied, with high rates of carbapenem and cephalosporin resistance and lower levels of colistin resistance in Lebanon. Studies from Iraq found high cephalosporin and colistin resistance along with increased susceptibility to carbapenems. In Jordan, most studies recorded high resistance to cephalosporins along with high susceptibility to carbapenems and colistin. Studies on P. aeruginosa isolates were limited: most isolates in Lebanon were carbapenem-resistant and colistin-susceptible; studies in Iraq showed varying levels of resistance to carbapenems and cephalosporins with high susceptibility to colistin; and studies in Jordan found varying levels of susceptibility to carbapenems, cephalosporins and colistin. The most commonly observed resistance mechanisms in GNB were genetic modifications causing increased expression of antimicrobial-inactivating enzymes and decreased permeability. Overall, this review highlights the concerning rise in AMR and the need for improved understanding of the resistance mechanisms to better inform healthcare providers when recommending treatment for patients in this region.

Retrospective Assessment of Ventilator-Associated Pneumonias due to Acinetobacter baumannii in an Oncology Hospital

Objectives:

Ventilator-associated pneumonia (VAP) is associated with significant morbidity and mortality in critically ill patients and leads to increases in health-care costs. However, it is preventable, and hospitals can decrease VAP rates. This study aims to retrospectively assess VAP rates in the intensive care unit of Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital of the University of Health Sciences, with reference to Acinetobacter baumannii, one of the causative organisms.

Methods:

This study enrolled a total of 2277 patients hospitalized between the years of 2011 and 2015. The required data were collected by reviewing medical files of the patients through computerized hospital databases. VAP rate and ventilator utilization (VU) ratio were calculated using the United States Center for Disease Control National Healthcare Safety Network methodology.

Results:

Of the study patients, 302 (13.26%) were seen to have developed VAP. Among these patients, 191 (63.25%) were microbiologically diagnosed VAP caused by A. baumannii. Pooled means of VU ratio and VAP rate were 0.70 and 22.91, respectively.

Conclusion:

The results of this study will motivate the infection control committee of the study hospital to assess current infection control program and strategies so that high VAP rate in the study intensive care unit can be reduced to the minimum possible level.

The global prevalence of multidrug-resistance among Acinetobacter baumannii causing hospital-acquired and ventilator-associated pneumonia and its associated mortality: A systematic review and meta-analysis

OBJECTIVE

The objective of this works was to assess the global prevalence of multidrug-resistance among A. baumannii causing hospital-acquired (HAP) and ventilator-associated pneumonia (VAP), and describe its associated mortality.

METHODS

We performed a systematic search of four databases for relevant studies. Meta-analysis was done based on United Nations geoscheme regions, individual countries and study period. We used a random-effects model to calculate pooled prevalence and mortality estimates with 95% confidence intervals (CIs), weighted by study size.

RESULTS

Among 6445 reports screened, we identified 126 relevant studies, comprising data from 29 countries. The overall prevalence of multidrug-resistance among A. baumannii causing HAP and VAP pooled from 114 studies was 79.9% (95% CI 73.9-85.4%). Central America (100%) and Latin America and the Caribbean (100%) had the highest prevalence, whereas Eastern Asia had the lowest (64.6%; 95% CI, 50.2-77.6%). The overall mortality estimate pooled from 27 studies was 42.6% (95% CI, 37.2-48.1%).

CONCLUSIONS

We observed large amounts of variation in the prevalence of multidrug-resistance among A. baumannii causing HAP and VAP and its mortality rate among regions and lack of data from many countries. Data from this review can be used in the development of customized strategies for infection control and antimicrobial stewardship.

Meropenem/colistin versus meropenem/ampicillin-sulbactam in the treatment of carbapenem-resistant pneumonia

AIM

Efficacy of colistin and ampicillin-sulbactam have not been compared in treatment of ventilator-associated pneumonia due to A. baumannii. Efficacy of colistin and ampicillin-sulbactam in combination with meropenem were compared in treatment of ventilator-associated pneumonia due to carbapenem-resistant A. baumannii.

METHOD

47 patients with ventilator-associated pneumonia due to carbapenem-resistant A. baumannii were randomized to receive meropenem/colistin or meropenem/ampicillin-sulbactam for 14 days. Clinical and microbiological responses and 28-day mortality were considered as outcomes.

RESULTS

Clinical response (75 vs 69.6%; p = 0.75) and microbial eradication (87.50 vs 91.3%; p = 0.59) were comparable between meropenem/colistin and meropenem/ampicillin-sulbactam groups, respectively.

CONCLUSION

In this study, clinical and microbiological response were comparable between the meropenem/colistin and meropenem/ampicillin-sulbactam groups.

Early administration of appropriate antimicrobial agents to improve the outcome of carbapenem-resistant Acinetobacter baumannii complex bacteraemic pneumonia

Carbapenem-resistant Acinetobacter baumannii complex (CRABC) is an emerging pathogen that causes bloodstream infections and nosocomial pneumonia. This study aimed to describe severe infection associated with CRABC bacteraemic pneumonia and to investigate risk factors for 28-day mortality. All patients aged ≥18 years with CRABC bacteraemic pneumonia were enrolled retrospectively at five teaching hospitals in South Korea. Empirical antimicrobial therapy was defined as appropriate if administration of at least one antimicrobial agent, to which the causative pathogen was susceptible, for >48 h, within 5 days of the onset of bacteraemia. During the study period, 146 patients with CRABC bacteraemic pneumonia were enrolled. Among them, 128 (87.7%) patients were treated in the intensive care unit; of these, 110 (75.3%) had ventilator-associated pneumonia. A total of 42 patients (28.8%) received appropriate empirical therapy. There was no difference in baseline characteristics between the appropriate and inappropriate empirical treatment groups. However, 28-day mortality was higher in the inappropriate therapy group (54.8% vs. 76.9%; P = 0.008). Multivariate Cox regression analysis revealed that Acute Physiology and Chronic Health Evaluation (APACHE) II score ≥20 [hazard ratio (HR)  = 1.28, 95% confidence interval (CI) 1.04-1.58; P = 0.02], septic shock (HR = 3.49, 95% CI 2.15-5.67; P <0.001) and inappropriate empirical therapy (HR = 3.24, 95% CI 1.94-5.42; P <0.001) were independently associated with an adverse outcome. In conclusion, the mortality rate of CRABC bacteraemic pneumonia was extremely high. Appropriate empirical therapy might improve the outcome of patients with CRABC bacteraemic pneumonia.

Future Directions and Molecular Basis of Ventilator Associated Pneumonia

Mechanical ventilation is a lifesaving treatment and has complications such as ventilator associated pneumonia (VAP) that lead to high morbidity and mortality. Moreover VAP is the second most common hospital-acquired infection in pediatric intensive care units. Although it is still not well understood, understanding molecular pathogenesis is essential for preventing and treating pneumonia. A lot of microbes are detected as a causative agent of VAP. The most common isolated VAP pathogens in pediatric patients are Staphylococcus aureus, Pseudomonas aeruginosa, and other gram negative bacteria. All of the bacteria have different pathogenesis due to their different virulence factors and host reactions. This review article focused on mechanisms of VAP with molecular pathogenesis of the causative bacteria one by one from the literature. We hope that we know more about molecular pathogenesis of VAP and we can investigate and focus on the management of the disease in near future.

Trend of extensively drug-resistant Acinetobacter baumannii and the remaining therapeutic options: a multicenter study in Tehran, Iran over a 3-year period

Comprehensive data on drug-resistant patterns of Acinetobacter baumannii isolates in developing countries is limited. We conducted a multihospital study to assess the rate and trend of drug-resistant phenotypes in Ac. baumannii using standardized definitions and to determine the remaining therapeutic options against resistant phenotypes. The 401 nonduplicate isolates were collected from six hospitals which are geographically distributed across Tehran, Iran over a 3-year period. Following PCR of bla_OXA-51-like gene, susceptibility testing was performed against nine antimicrobial agent categories. Three hundred and ninety (97%) isolates were resistant to least two carbapenems; carbapenem-resistant Ac. baumannii. The majority of isolates (366, 91·3%) were extensively drug resistant (XDR) and the rest of the isolates were classified as multidrug resistant (26, 6·8%) and susceptible (9, 2·2%). The rate of XDR-AB slightly decreased from 93·8% in 2011 to 89·8% in 2013. A considerable decrease in resistance to doxycycline, minocycline and tigecycline was demonstrated. The XDR-AB isolates showed susceptibility to gentamicin (10·4%), tobramycin (23%), ampicilin-sulbactam (30·1%), minocycline (32·8%), tigecycline (10·7%), doxycycline (21·6%), colistin (100%) and polymixin B (100%). We demonstrated the rising trend of resistance to all antibiotic categories except tetracyclines and folate pathway inhibitors. We found that the treatment options against XDR-AB are extremely limited and each treatment alternative including even old, but safe, antibiotics might be considered.

SIGNIFICANCE AND IMPACT OF THE STUDY

The high frequency of drug-resistant phenotypes including carbapenem-resistant Acinetobacter baumannii, multidrug-resistant, and extensively resistant has been demonstrated in Ac. baumannii isolates tested here. As the antibiotic resistance pattern of isolates varies in different geographical regions, this study can provide comprehensive information about the antibiotic resistance profile of Ac. baumannii isolates in Tehran. In addition, the resistance profiles could be effectively considered by clinicians to manage antibiotic therapy. This work also emphasizes on the prudent use of antibiotics and the monitoring of antibiotic susceptibility trend and rate.

Expression of Toll-like receptor 4 in lungs of immune-suppressed rat with Acinetobacter baumannii infection

Toll-like receptor 4 (TLR4) is involved in the regulation of host responses to Acinetobacter baumannii (A. baumannii). The aim of the present study was to examine the function of TLR4 in lung inflammation in immune-suppressed rats with A. baumannii infection. A total of 72 Sprague-Dawley male rats were randomly divided into the control, A. baumannii infection and immune-suppressed infection groups. The immune-suppressed infection group was treated with 100 mg/kg hydrocortisone by subcutaneous injection every other day for 2 weeks prior to A. baumannii infection. Lung tissue was obtained on the 3rd and 7th day after tracheal inoculation with A. baumannii. The expression of TLR4 in bronchial and alveolar epithelial cells, and alveolar macrophage was examined using immunohistochemistry. The levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α in bronchoalveolar lavage fluid were detected using ELISA. The results showed that in the control group, the expression of TLR4 was upregulated in the bronchial and alveolar epithelial, and alveolar macrophages, and the levels of IL-6 and TNF-α were increased in the early phase of A. baumannii infection. On the 7th day, no significant difference in the levels of IL-6 and TNF-α was observed between the A. baumannii infection and control groups. Conversely, the expression of TLR4 was downregulated in the immune-suppressed group, and the levels of IL-6 and TNF-α were reduced on the 3rd day after infection. In the subsequent observation period, the expression of TLR4 was upregulated and the levels of IL-6 and TNF-α were increased. In conclusion, the results show a critical role of TLR4 in mediating effective immune response in the lung of rat with A. baumannii infection.