Healthcare-associated Gram-negative bloodstream infections: antibiotic resistance and predictors of mortality

Global burden associated with 85 pathogens in 2019: a systematic analysis for the Global Burden of Disease Study 2019

BACKGROUND

Despite a global epidemiological transition towards increased burden of non-communicable diseases, communicable diseases continue to cause substantial morbidity and mortality worldwide. Understanding the burden of a wide range of infectious diseases, and its variation by geography and age, is pivotal to research priority setting and resource mobilisation globally.

METHODS

We estimated disability-adjusted life-years (DALYs) associated with 85 pathogens in 2019, globally, regionally, and for 204 countries and territories. The term pathogen included causative agents, pathogen groups, infectious conditions, and aggregate categories. We applied a novel methodological approach to account for underlying, immediate, and intermediate causes of death, which counted every death for which a pathogen had a role in the pathway to death. We refer to this measure as the burden associated with infection, which was estimated by combining different sources of information. To compare the burden among all pathogens, we used pathogen-specific ratios to incorporate the burden of immediate and intermediate causes of death for pathogens modelled previously by the GBD. We created the ratios by using multiple cause of death data, hospital discharge data, linkage data, and minimally invasive tissue sampling data to estimate the fraction of deaths coming from the pathway to death chain. We multiplied the pathogen-specific ratios by age-specific years of life lost (YLLs), calculated with GBD 2019 methods, and then added the adjusted YLLs to age-specific years lived with disability (YLDs) from GBD 2019 to produce adjusted DALYs to account for deaths in the chain. We used standard GBD methods to calculate 95% uncertainty intervals (UIs) for final estimates of DALYs by taking the 2·5th and 97·5th percentiles across 1000 posterior draws for each quantity of interest. We provided burden estimates pertaining to all ages and specifically to the under 5 years age group.

FINDINGS

Globally in 2019, an estimated 704 million (95% UI 610-820) DALYs were associated with 85 different pathogens, including 309 million (250-377; 43·9% of the burden) in children younger than 5 years. This burden accounted for 27·7% (and 65·5% in those younger than 5 years) of the previously reported total DALYs from all causes in 2019. Comparing super-regions, considerable differences were observed in the estimated pathogen-associated burdens in relation to DALYs from all causes, with the highest burden observed in sub-Saharan Africa (314 million [270-368] DALYs; 61·5% of total regional burden) and the lowest in the high-income super-region (31·8 million [25·4-40·1] DALYs; 9·8%). Three leading pathogens were responsible for more than 50 million DALYs each in 2019: tuberculosis (65·1 million [59·0-71·2]), malaria (53·6 million [27·0-91·3]), and HIV or AIDS (52·1 million [46·6-60·9]). Malaria was the leading pathogen for DALYs in children younger than 5 years (37·2 million [17·8-64·2]). We also observed substantial burden associated with previously less recognised pathogens, including Staphylococcus aureus and specific Gram-negative bacterial species (ie, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, and Helicobacter pylori). Conversely, some pathogens had a burden that was smaller than anticipated.

INTERPRETATION

Our detailed breakdown of DALYs associated with a comprehensive list of pathogens on a global, regional, and country level has revealed the magnitude of the problem and helps to indicate where research funding mismatch might exist. Given the disproportionate impact of infection on low-income and middle-income countries, an essential next step is for countries and relevant stakeholders to address these gaps by making targeted investments.

FUNDING

Bill & Melinda Gates Foundation, Wellcome Trust, and Department of Health and Social Care using UK aid funding managed by the Fleming Fund.

Predictive modeling of mortality in carbapenem-resistant Acinetobacter baumannii bloodstream infections using machine learning

Acinetobacter baumannii, a notable drug-resistant bacterium, often induces severe infections in healthcare settings, prompting a deeper exploration of treatment alternatives due to escalating carbapenem resistance. This study meticulously examined clinical, microbiological, and molecular aspects related to in-hospital mortality in patients with carbapenem-resistant A. baumannii (CRAB) bloodstream infections (BSIs). From 292 isolates, 153 cases were scrutinized, reidentified through matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and evaluated for antimicrobial susceptibility and carbapenemase genes via multiplex polymerase chain reaction (PCR). Utilizing supervised machine learning, the study constructed models to predict 14- and 30-day mortality rates, revealing the Naïve Bayes model's superior specificity (0.75) and area under the curve (0.822) for 14-day mortality, and the Random Forest model's impressive recall (0.85) for 30-day mortality. These models delineated eight and nine significant features for 14- and 30-day mortality predictions, respectively, with "septic shock" as a pivotal variable. Additional variables such as neutropenia with neutropenic days prior to sepsis, mechanical ventilator support, chronic kidney disease, and heart failure were also identified as ranking features. However, empirical antibiotic therapy appropriateness and specific microbiological data had minimal predictive efficacy. This research offers foundational data for assessing mortality risks associated with CRAB BSI and underscores the importance of stringent infection control practices in the wake of the scarcity of new effective antibiotics against resistant strains. The advanced models and insights generated in this study serve as significant resources for managing the repercussions of A. baumannii infections, contributing substantially to the clinical understanding and management of such infections in healthcare environments.

Bloodstream Infections Caused by Multidrug Resistant Bacteria: Clinical and Microbiological Features and Mortality

Objectives

Bloodstream infections (BSI) are associated with high morbidity and mortality. The aim of our study is to determine whether there is a relationship between certain risk factors such as the underlying disease, patient's medical history, or interventional procedures and multidrug resistant (MDR) bacterial infection and to determine the risk factors for mortality.

Methods

Two hundred and twenty-two outpatients and inpatients who were diagnosed with bacteremia over a 6-month period were included in the study. 232 agents from 222 patients were isolated and tested for antimicrobial susceptibility. The relationship between patients demographic and clinical data and MDR was analyzed.

Results

The most common microorganisms were Gram-negative bacteria (59.4%), Gram-positive bacteria (36.9%), Candida species (2.2%), and anaerobic bacteria (1.35%). The most common isolates were Escherichia coli 53 (22.8%), Staphylococcus aureus 35 (%15.1), Klebsiella pneumoniae 26 (11.2%), Pseudomonas spp. (n=17, 7.3%), Acinetobacter spp 17 (7.3%), and Enterococcus spp 14 (6%). Microorganisms with the highest antimicrobial resistance observed were 82.3% in Acinetobacter baumannii, 64.5% in coagulase-negative staphylococci, 60.3% in E. coli, 50% in K. pneumoniae, and 27.2% in Enterobacterales spp. Most patients with BSI caused by MDR bacteria were in the intensive care unit (64%). Sepsis diagnosis, urinary catheter use, history of surgery, and use of broad-spectrum antibiotics as well as risk factors for antibiotic-resistant bacteremia, coronary artery disease, inappropriate empirical therapy, healthcare-associated infections, urinary catheterization, and stay in the ICU were determined as risk factors for mortality.

Conclusion

Our study identified the risk factors of BSI caused by MDR bacteria and helped to reveal the relationship between these factors and mortality.

Does Emerging Carbapenem Resistance in Acinetobacter baumannii Increase the Case Fatality Rate? Systematic Review and Meta-Analysis

BACKGROUND

In the era of rising carbapenem resistance, we aimed to investigate the change in mortality rate and positivity of carbapenemase genes in Acinetobacter baumannii.

METHODS

Preferred Reporting Items for Systematic Review (PRISMA) guidelines were adopted in this systematic review. Our literature search included the Cochrane Library, Pubmed, Scopus, Web of Science, Medline, Tubitak TR Dizin, and Harman databases for studies dating back from 2003 to 2023 reporting bloodstream A. baumannii infections in Türkiye. A simple linear regression model was used to determine the association between resistance, mortality, and time.

RESULTS

A total of 1717 studies were identified through a literature search, and 21 articles were selected based on the availability of the data regarding mortality and resistance rate (four articles) or the molecular epidemiology of carbapenem-resistant A. baumannii (17 articles) in Türkiye. From 2007 to 2018, the carbapenem resistance rate increased (p = 0.025). The OXA-23 and OXA-58 positivities were inversely correlated (p = 0.025).

CONCLUSIONS

Despite the emergence of carbapenem resistance, mortality did not increase in parallel, which may be due to improved medical advancements or the fitness cost of bacteria upon prolonged antimicrobial exposure. Therefore, we suggest further global research with the foresight to assess clonal relatedness that might affect the carbapenem resistance rate.

Decreasing the incidence of central line-associated bloodstream infection in a medical intensive care unit: a best practice implementation project

INTRODUCTION AND OBJECTIVES

Bloodstream infections are common in critically ill patients using central venous access devices (CVAD) in intensive care units (ICU). This project aimed to decrease the incidence of central line-associated bloodstream infections (CLABSI) by using evidence-based strategies.

METHODS

The project applied the JBI audit and feedback methods. Thirty-two nurses and five resident physicians from the medical ICU of a medical center participated in the project. Preintervention compliance was measured for the 11 key evidence-based criteria (six audit criteria of central venous catheter insertion and five audit criteria of dressing and catheter securement). Strategies were implemented to overcome the barriers identified in the baseline assessment. Impact evaluation and sustainability were conducted to change the CLABSI rate and the competence of healthcare professionals in providing CVAD care. The JBI Practical Application of Clinical Evidence System and Getting Research into Practice audit tools were used for the data collection, analysis, and implementation planning.

RESULTS

Barriers included insufficient knowledge among nurses and physicians, poor compliance with the standard CVAD insertion procedure by physicians, inadequate cooperation among the CVAD care team members, and lack of CVAD-related equipment. The strategies included education and training in CVAD care, the establishment of a team resource management program, and the provision of appropriate equipment. Following project implementation, the CLABSI rate decreased from 8.38 to 3.9 BSIs/1000 CVAD-days.

CONCLUSIONS

The project successfully decreased the CLABSI rate and increased the competence of healthcare professionals. Implementation of best practices in clinical care should focus on leadership, team resource management, education, monitoring, and innovation.

An Overview on Phenotypic and Genotypic Characterisation of Carbapenem-Resistant Enterobacterales

Improper use of antimicrobials has resulted in the emergence of antimicrobial resistance (AMR), including multi-drug resistance (MDR) among bacteria. Recently, a sudden increase in Carbapenem-resistant Enterobacterales (CRE) has been observed. This presents a substantial challenge in the treatment of CRE-infected individuals. Bacterial plasmids include the genes for carbapenem resistance, which can also spread to other bacteria to make them resistant. The incidence of CRE is rising significantly despite the efforts of health authorities, clinicians, and scientists. Many genotypic and phenotypic techniques are available to identify CRE. However, effective identification requires the integration of two or more methods. Whole genome sequencing (WGS), an advanced molecular approach, helps identify new strains of CRE and screening of the patient population; however, WGS is challenging to apply in clinical settings due to the complexity and high expense involved with this technique. The current review highlights the molecular mechanism of development of Carbapenem resistance, the epidemiology of CRE infections, spread of CRE, treatment options, and the phenotypic/genotypic characterisation of CRE. The potential of microorganisms to acquire resistance against Carbapenems remains high, which can lead to even more susceptible drugs such as colistin and polymyxins. Hence, the current study recommends running the antibiotic stewardship programs at an institutional level to control the use of antibiotics and to reduce the spread of CRE worldwide.

Therapeutic Effects of Boric Acid in a Septic Arthritis Model Induced by Escherichia coli in Rats

The study aimed to evaluate the therapeutic effect of boric acid (BA) in experimentally induced septic arthritis. A total of 30 rats, 6 rats in each group (5 groups), were used in the study. No treatment was applied to the rats in the control group. Only BA was administered intraperitoneally (IP) to the rats in the bor group. Escherichia coli was administered at a single dose of 25 μL, 1 × 10¹⁰ cfu/rat from the right foot pad of the rats, via intra-articular route, to the mice in the arthritis, arthritis-bor, and arthritis-antb groups. Then, BA at a dose of 50 mg/kg and cefazolin at a dose of 25 mg/kg were administered to the rats in the arthritis-bor and arthritis-antb groups, respectively, for 7 days via the IP route. At the end of the study, all animals were euthanized following the ethical rules. Blood and tissue samples were taken from the rats for biochemical and histopathological analyses. The levels of GSH, MDA, Endoglin, Endocan, and TNF-β markers were measured in the blood samples taken. A significant decrease was observed in MDA and Endoglin levels in the boric acid-administered group compared with the arthritis group, while a significant increase was observed at the GSH level. Histopathologically, it was determined that the reactive surrounding tissue response in the bor group was significantly reduced. As a result, a significant decrease in inflammation was found biochemically and histopathologically in the groups treated with BA.

Antimicrobial susceptibility to polymyxin B and other comparators against Gram-negative bacteria isolated from bloodstream infections in China: Results from CARVIS-NET program

Objective

To investigate the bacterial distribution and antimicrobial resistance profile of clinical isolates from Gram-negative bacteria bloodstream infections (GNBSI) in China.

Methods

The clinical bacterial strains isolated from blood culture were collected during April 2019 to December 2021 in 21 member hospitals of China Bloodstream Gram-negative Pathogens Antimicrobial Resistance and Virulence Surveillance Network (CARVIS-NET). Antibiotic susceptibility test was conducted by broth microdilution method recommended by Clinical and Laboratory Standards Institute (CLSI, United States). WHONET 2021 and SPSS 22.0 were used to analyze data.

Results

During the study period, 1939 Gram-negative bacteria were collected from 21 hospitals, among which 1,724 (88.9%) were Enterobacteriaceae, 207 (10.7%) were non-fermenting Gram-negative bacteria and 8 (0.4%) were others. The top five bacterial species were Escherichia coli (46.2%), Klebsiella pneumoniae (31.6%), Pseudomonas aeruginosa (4.9%), Acinetobacter baumannii (4.2%) and Enterobacter cloacae (3.0%). For K. pneumoniae, antibiotic resistance was mainly prevalent in hospital-associated bloodstream infections, while for A. baumannii, antibiotic resistance was mainly prevalent in community-associated bloodstream infections. It is worth mentioning that 94.1% of the 1939 Gram-negative isolates were susceptible to polymyxin B. The sensitivity of the strains involved in our investigation to polymyxin B is highly correlated with their sensitivity to colistin.

Conclusion

The surveillance results in CARVIS-NET-2021 showed that the main pathogens of GNBSI in China were Enterobacteriaceae, while E. coli was the most common pathogen. The resistance rates of K. pneumonia, P. aeruginosa, A. baumannii, and E. cloacae to multiple antibiotics kept on a high level. In many cases, polymyxin B and colistin has become the last-resort agents to combat bloodstream infections caused by multidrug-resistant (MDR) Gram-negative bacteria.

Efficacy of Amikacin and Meropenem on Colistin-Induced Klebsiella pneumoniae Persisters

Colistin-based antibiotic therapies have been recommended for the treatment of multidrug-resistant Klebsiella pneumoniae infections. During colistin treatment, persister cells that tolerate antibiotics may arise. Here we designed an in vitro study to assess the killing activity of colistin, meropenem, and amikacin on colistin-induced K. pneumoniae persisters in comparison with starvation-induced persisters. Colistin-induced persisters were generated under exposure to 10 × minimum inhibitory concentration dose of colistin, whereas starvation-induced persisters were produced by limitation of nutrients. In colistin-induced persisters, amikacin totally inhibited cell growth in 6 hours, whereas 98% of the cell population was inhibited by meropenem, and total eradication with meropenem was observed after 24 hours. Both antibiotics also inhibited metabolic activity >88%. The lack of killing effect under colistin exposure suggested to us that these cells could protect themselves from further colistin stress. There was no significant permeabilization change in the cellular membrane with all antibiotics. There was no killing effect on starvation-induced persister cells with the exposure to all antibiotics. In 6 hours, the metabolic activity of the persisters with meropenem and colistin increased 99% and 40%, respectively, whereas there was no increase with amikacin. The sustained inhibition with amikacin was an important finding for antipersister effect of amikacin. Amikacin had rapid and sustained antipersister activity on colistin-induced persister cells. During the colistin treatment of K. pneumoniae infection, the addition of amikacin to the regimen seems to be an effective approach to prevent a recurrence.

A meta-analysis for the role of aminoglycosides and tigecyclines in combined regimens against colistin- and carbapenem-resistant Klebsiella pneumoniae bloodstream infections

We aimed to describe the effect of aminoglycosides and tigecycline to reduce the mortality in colistin- and carbapenem-resistant Klebsiella pneumoniae (ColR-CR-Kp) infections. We included the studies with defined outcomes after active or non-active antibiotic treatment of ColR-CR-Kp infections. The active treatment was defined as adequate antibiotic use for at least 3 days (72 h) after the diagnosis of ColR-CR-Kp infection by culture. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement and the checklist of PRISMA 2020 was applied. Crude and adjusted odds ratios (OR) with 95% confidence interval (CI) were calculated and pooled in the random effects model. Adding aminoglycosides to the existing treatment regimen reduced overall mortality significantly (OR 0.34, 95% CI 0.20-0.58). Overall mortality was 34% in patients treated with aminoglycoside-combined regimens and was 60% in patients treated with non-aminoglycoside regimens. Treatment with tigecycline is not found to reduce mortality (OR: 0.76, 95% CI: 0.47-1.23). Our results suggest that aminoglycoside addition to the existing regimen of colistin- and carbapenem-resistant Klebsiella pneumoniae infections reduces mortality significantly.

The Effect of Antimicrobial Policy Implementation on Carbapenem Resistance: A University Hospital Experience

Objective: The resistance of Gram-negative bacteria to antibiotics is a global issue that leads to increased mortality and treatment costs. The aim of this study is to see how a newly formed carbapenem control team affected the prevalence of carbapenem-resistant Gram-negative rods and antibiotic consumption expenses in 2017 compared to the year before. Methods: The rate of carbapenem antibiotic usage in Intensive Care Units and Bone Marrow Transplantation services, as well as the findings of culture materials obtained from various body parts of the same patients, between January 1, 2016, and December 31, 2017 were assessed. Results: While there was an ordinary restriction on carbapenem consumption in 2016, carbapenem consumption has been more restricted in 2017. The carbapenem-resistant Gram-negative bacteria patterns of culture materials are examined and compared with Defined Daily Dose data of carbapenems. After the restriction, a significant decrease in the consumption of carbapenems was detected. The decline in carbapenem-resistant Gram-negative bacteria and decreasing antibiotic consumption were found to have a moderately positive correlation (r=0.641, p=0.02). A 60.9% decrease was observed in carbapenem costs after carbapenem restriction, on the other hand, an increase in other unrestricted antibiotics was apparent. Conclusion: Antimicrobial restriction policies can help minimize the rate of carbapenem-resistant Gram-negative rods, which is a serious problem in healthcare. We demonstrated that a decrease in carbapenem-resistant Gram-negative rods isolation rates can lead to a decrease in healthcare-associated infections. Although there is no decrease in the direct antibiotics cost, a drop in carbapenem-resistant may lower the expenses of drastic consequences of infections with carbapenem-resistant and its cost. we can conclude that the Antibiotic Control Policy should be modified based on this new information.

The Effectiveness of Bundle Applications in the Prevention of Central Line-associated Bloodstream Infections: Nine Years of Observation

Objective

This study aimed to assess the effectiveness of chlorhexidine-impregnated dressing in a bundle of interventions to reduce the rate of central line-associated bloodstream infections (CLABSIs).

Materials and Methods

We performed a bundle of interventions to reduce the CLABSIs from 2012. As one bundle component, we started using the chlorhexidine impregnated catheter dressing. We used a document describing applying central venous catheters for the practicing physicians and nurses, and we organized several educational meetings. An interrupted time-series analysis was performed.

Results

Seventy-six CLABSI events were detected in total between January 1, 2011, and December 31, 2019. Twenty-six cases were detected in the pre-intervention period (January 1, 2011, to December 31, 2011), and 50 patients were seen in the post-intervention term (January 1, 2012, to December 31, 2019). The annual CLABSI rate was 2.60/1000 catheter days in the pre-intervention period and 0.46/1000 catheter days (p=0.0328) in the post-intervention period. The CLABSI rate among hematology-oncology inpatients decreased from 3.39 to 0.71 (p=0.0101) in the same term.

Conclusion

By using bundle form including chlorhexidine impregnated dressing, the rate of CLABSIs decreased significantly. This effect has been observed consistently for nine years, and the clinical pathway use has become the standard care protocol.

Factors associated with mortality in younger and older (≥75 years) hospitalized patients with community-acquired pneumonia

BACKGROUND

Pneumonia is among the most serious infections in the elderly. The evaluation of prognosis and predicting the outcome is essential in managing the treatment of patients with pneumonia.

OBJECTIVE

Evaluate factors that might affect the mortality of elderly patients hospitalized for community-acquired pneumonia (CAP) in two age groups.

DESIGN

Medical record review.

SETTINGS

Tertiary care hospital.

PATIENTS AND METHODS

The study included CAP patients who were hospitalized during the period from January 2017 and December 2019. The CURB-65 scale was chosen to assess the severity of pneumonia on admission. Multivariate analyses were conducted separately for patients younger than 75 years and 75 years or older.

MAIN OUTCOME MEASURES

30-day mortality, factors associated with mortality.

SAMPLE SIZE AND CHARACTERISTICS

1603 patients with a median age of 74, including 918 women (57%).

RESULTS

The 30-day mortality rate was 6.5%. Patients with carbapenem-resistant gram-negative bacteria had lower survival rates (P<.0001). In the multivariate analysis, age, lung cancer, CURB-65, carbapenem resistance, and duration of hospital stay were associated with mortality in patients aged 75 years or older. Lung cancer, malignant disease, carbapenem resistance, duration of hospital stay and procalcitonin level were associated with mortality under the age of 75. Of 640 sputum cultures tested, P aeruginosa (42%) was the most common pathogen.

CONCLUSION

The risk factors that affected mortality differed among patients aged 75 years or older versus younger patients. Our findings are important in determining factors associated with mortality in managing the treatment and follow up of hospitalized CAP patients younger or 75 years of age or older.

LIMITATIONS

Single-center, retrospective.

CONFLICT OF INTEREST

None.

Elimination of healthcare-associated Acinetobacter baumannii infection in a highly endemic region

This paper describes the elimination of healthcare-associated Acinetobacter baumannii infections in a highly endemic region. A prospective, observational study was performed between October 2012 and October 2017. Acinetobacter baumannii were isolated from 59 patients, and >95% similarity was demonstrated among isolates of seven patients (DiversiLab™, BioMérieux). Carbapenemase activity was detected in 15 of 17 (88%) isolates, and all were OXA-23 type. The control of Acinetobacter baumannii outbreaks can be achieved by close follow-up supported by molecular techniques, strict application of infection control measures, and isolation of transferred patients.

Evaluation of Benzguinols as Next-Generation Antibiotics for the Treatment of Multidrug-Resistant Bacterial Infections

Our recent focus on the “lost antibiotic” unguinol and related nidulin-family fungal natural products identified two semisynthetic derivatives, benzguinols A and B, with unexpected in vitro activity against Staphylococcus aureus isolates either susceptible or resistant to methicillin. Here, we show further activity of the benzguinols against methicillin-resistant isolates of the animal pathogen Staphylococcus pseudintermedius, with minimum inhibitory concentration (MIC) ranging 0.5–1 μg/mL. When combined with sub-inhibitory concentrations of colistin, the benzguinols demonstrated synergy against Gram-negative reference strains of Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa (MICs of 1–2 μg/mL in the presence of colistin), whereas the benzguinols alone had no activity. Administration of three intraperitoneal (IP) doses of 20 mg/kg benzguinol A or B to mice did not result in any obvious adverse clinical or pathological evidence of acute toxicity. Importantly, mice that received three 20 mg/kg IP doses of benzguinol A or B at 4 h intervals exhibited significantly reduced bacterial loads and longer survival times than vehicle-only treated mice in a bioluminescent S. aureus murine sepsis challenge model. We conclude that the benzguinols are potential candidates for further development for specific treatment of serious bacterial infections as both stand-alone antibiotics and in combination with existing antibiotic classes.

A meta-analysis of antibiotic resistance rates in Pseudomonas aeruginosa isolated in blood cultures in Turkey between 2007 and 2017

OBJECTIVE:

The prevalence of Pseudomonas aeruginosa has remained stable in recent years, and resistant strains has increased dramatically. In this meta-analysis, we aimed to analyze the P. aeruginosa strains isolated from blood cultures in Turkey during the last 11 years and to reveal their antimicrobial susceptibility.

METHODS:

Data collected between 2007 and 2017 were divided into two groups as Group-1; 2007–2011 and Group-2; 2012–2017. The differences in antibiotic resistance rates between Group-1 and Group-2 were analyzed. The study data were included according to PRISMA criteria, then meta-analysis was performed.

RESULTS:

A total of 30 study data from 25 studies were included in the study. The prevalence rate of meropenem (MEM) resistance in P. aeruginosa in Turkey was 25.1% (95% Cl: 20.65–29.83) according to a meta-analysis of 637 isolates. MEM resistance rates in Group-1 and Group-2 were 23.4% (95% Cl: 18.34–28.99) and 29.3% (95% Cl: 21.23–38.23), respectively. The prevalence rate of imipenem (IMP) resistance in P. aeruginosa in Turkey was 26.8% (%95 Cl: 23.40–30.35) according to a meta-analysis of 1421 isolates. IMP resistance rates in Group-1 and Group-2 were 26.2% (95% Cl: 22.41–30.27) and 28.4% (95% Cl: 21.57–35.88), respectively. Ciprofloxacin (CIP) resistance rate was 27.04% (95% Cl: 21.88–32.52) in 1388 isolates. CIP resistance rates in Group-1 and Group-2 were 30.8% (95% Cl: 24.35–37.56) and 18.6% (95% Cl: 10.72–28.11), respectively. The prevalence rate of piperacillin-tazobactam (TZP) resistance in P. aeruginosa in Turkey was 29.2% (95% Cl: 21.058–38.088) according to a meta-analysis of 1030 isolates. TZP resistance rates in Group-1 and Group-2 were 26.1% (95% Cl: 17.76–35.31) and 38.2% (95% Cl: 18.48–60.27), respectively.

CONCLUSION:

There is a remarkable increase in resistance rates in P. aeruginosa to MEM and TZP in Turkey due to frequent use. Other antibiotics with antipseudomonal effect should be prioritized in the treatment of these infections.

Antisense peptide nucleic acid inhibits the growth of KPC-producing Klebsiella pneumoniae strain

Klebsiella pneumoniae causes common and severe hospital- and community-acquired infections with a high incidence of multidrug resistance (MDR) and mortality. In this study, we investigated the ability of the antisense peptide nucleic acids (PNA) conjugated to the (KFF)3K cell-penetrating peptide (CPP) to target the gyrA KPC-producing K. pneumoniae and inhibit bacterial growth in vitro. The inhibitory effect on gyrA gene was evaluated by measuring 16s gene amplification in KPC-producing K. pneumoniae treated with the antisense PNA conjugate. The hemolytic property of the antisense PNA conjugate was accessed toward mice red blood cells. Finally, molecular modeling and dynamics simulations analyses in aqueous solutions were performed to predict the PNA conformation alone in contact with DNA (gyrA gene sequence). PNA was capable of inhibiting bacterial growth at 50 μM, also reducing 16S gene amplification in 96.7%. Besides, PNA presented low hemolytic activity (21.1% hemolysis) at this same concentration. Bioinformatics analysis demonstrated that the structure of the PNA is stable in water without major changes in its secondary structure. The ability of PNA and its conjugated CPP ((KFF)3K) to inhibit bacterial growth demonstrates the potential of this new class of antibacterial agents, encouraging further in vivo studies to confirm its therapeutic efficacy.

Changes in antimicrobial resistance and outcomes of health care-associated infections

To describe the change in the epidemiology of health care-associated infections (HAI), resistance and predictors of fatality we conducted a nationwide study in 24 hospitals between 2015 and 2018. The 30-day fatality rate was 22% in 2015 and increased to 25% in 2018. In BSI, a significant increasing trend was observed for Candida and Enterococcus. The highest rate of 30-day fatality was detected among the patients with pneumonia (32%). In pneumonia, Pseudomonas infections increased in 2018. Colistin resistance increased and significantly associated with 30-day fatality in Pseudomonas infections. Among S. aureus methicillin, resistance increased from 31 to 41%.

Antimicrobial activity of plant extracts against carbapenem-producing Klebsiella pneumoniae and in vivo toxicological assessment

The global spread of multidrug-resistant strains has prompted the scientific community to explore novel sources of chemicals with antimicrobial activity. The aim of the study was to examine the antimicrobial activity in vitro of 28 extracts against carbapenem-producing Klebsiella pneumoniae, individually and in combination with antibiotics and in vivo toxicological assessment of the most active product. The multi-resistant K. pneumoniae strain was submitted for phenotypic and molecular characterization. The antibacterial activity of 28 plant extracts was evaluated alone and in combination with antibiotics against this strain through the agar disk diffusion. Of these, 16 extracts showed synergism against carbapenem-producing K. pneumoniae, being that B. crassifolia extract exhibited synergism with three antibiotics. Based on this assessment, B. crassifolia-extract-induced toxicity on Swiss male mice was evaluated by administering this extract and subsequently determining apoptosis and splenic phagocytosis using the comet and micronucleus assays. The results of this study showed that B. crassifolia extract had synergistic activity promising and groups treated with B. crassifolia exhibited no genotoxic or mutagenic activity, indicating that B. crassifolia extract exerted beneficial effects and appeared safe to use at the studied concentrations.

Molecular and epidemiological surveillance of polymyxin-resistant Klebsiella pneumoniae strains isolated from Brazil with multiple mgrB gene mutations

The prevalence of polymyxin-resistant Enterobacteriaceae is increasing worldwide. Their emergence is worrisome and limits therapeutic options for severely ill patients. We aimed to investigate the molecular and epidemiological characteristics of polymyxin-resistant Klebsiella pneumoniae circulating in Brazilian hospitals. Polymyxin-resistant K. pneumoniae isolates from two Brazilian healthcare facilities were characterized phenotypically and subjected to whole genome sequencing (WGS). Using the WGS data we determined their sequence type, resistance gene content (resistome), their composition of virulence genes and plasmids. ST11 was the most common (80 %) sequence type among the isolates followed by ST345, ST15 and ST258. A resistome analysis revealed the common presence of bla_KPC-2 and less frequently bla_SHV-11, bla_TEM-1, bla_CTX-M-15, and bla_OXA-9. Genes conferring resistance to aminoglycosides, fluoroquinolones, phenicols, sulphonamides, tetracyclines, trimethoprim and macrolide-lincosamide-streptogramin were also detected. We observed a clonal spread of polymyxin-resistant K. pneumoniae isolates, with polymyxin-resistance associated with various alterations in the mgrB gene including inactivation by an insertion sequence and nonsense point mutations. We additionally identified a novel 78-bp repeat sequence, encoding a MgrB protein with 26 amino acids duplicated in six isolates. This is the first observation of this type of alteration being associated with polymyxin resistance. Our findings demonstrate that mgrB alterations were the most common source of polymyxin-resistance in Brazilian clinical settings. Interestingly, distinct genetic events were identified among clonally related isolates, including a new amino acid alteration. The clinical implications and investigation of the resistance mechanisms is of great importance to patient safety and control of these infections, particularly in long-term care facilities.

Emergence of colistin and carbapenem-resistant Acinetobacter calcoaceticus-Acinetobacter baumannii (CCR-Acb) complex in a neurological intensive care unit followed by successful control of the outbreak

BACKGROUND

Colistin and carbapenem-resistant Acinetobacter calcoaceticus- Acinetobacter baumannii complex (CCR-Acb complex) was isolated from two consecutive patients in the neurological intensive care unit (NICU). An urgent reaction to this desperate situation was required.

PATIENTS AND METHODS

Screening cultures were taken from the other patients sharing the NICU with index patients and repeated periodically. NICU was closed for new admissions. Infection control precautions (ICP) such as hand hygiene, cohorting patients colonized with CCR-Acb complex, cohorting the staff caring for these patients, daily bathing with chlorhexidine gluconate impregnated clothes, using gowns when contacting with patients and patient care area, and sodium hypochlorite tablets for environmental cleaning were enforced.

RESULTS

Screening cultures revealed carbapenem-resistant Acb complex in 12 out of 32 patients and 8 of them were colonized with CCR-Acb complex. NICU was opened for new admissions one month later. No further new cases with CCR-Acb complex were detected by screening cultures after 6 weeks with enforcement of ICP. Moreover, the rate of nosocomial infections caused by other multi-drug resistant Gram-negative bacilli (MDR-GNB) decreased significantly when rates before and after closing the NICU were compared.

CONCLUSION

ICP were effective not only to limit the spread of CCR-Acb complex but also decreased the incidence of other MDR-GNB infections when applied adequately.

The effect of colistin resistance and other predictors on fatality among patients with bloodstream infections due to Klebsiella pneumoniae in an OXA-48 dominant region

BACKGROUND

The aim of this study was to determine the effect of colistin resistance and other predictors on fatality among patients with Klebsiella pneumoniae bloodstream infections (Kp-BSI) and to describe the effect of amikacin and tigecycline on the outcome in an OXA-48 dominant country.

METHOD

This was a retrospective study performed among patients >16 years of age in a tertiary hospital with 465 beds. All cases had ≥1 positive blood culture for K. pneumoniae 48 h after admission.

RESULTS

Among 210 patients with Kp-BSI, the 30-day mortality rate after isolation of the microorganism was 58%. The rate of carbapenem resistance was higher (64% vs. 38%, p < 0.001) and the colistin minimum inhibitory concentration (MIC) was elevated (7 vs. 4, p < 0.029) among the patients who died. Among the colistin-resistant K. pneumoniae, the rates of OXA-48, ST101, and NDM-1 were 78%, 67%, and 35%, respectively. Amikacin was added to the treatment of 13 patients with carbapenem and colistin-resistant Kp-BSI and 77% survived (p < 0.001). Tigecycline was added to the treatment of 24 patients with carbapenem and colistin-resistant Kp-BSI, and the 30-day mortality rate was 71% (p = 0.576). In the multivariate analysis, carbapenem resistance (odds ratio (OR) 5.2, 95% confidence interval (CI) 2.47-10.9, p < 0.001) and increasing APACHE II score (OR 1.19, 95% CI 1.12-1.26, p < 0.001) were significantly associated with 30-day mortality. The addition of amikacin to the treatment regimen (OR 0.05, 95% CI 0.01-0.23, p < 0.001) was significantly beneficial.

CONCLUSIONS

Carbapenem resistance, increasing MIC of colistin, and the lungs as the source of the infection were significantly associated with 30-day mortality. The empirical use of combined active aminoglycosides was found to be beneficial in the treatment of colistin-resistant K. pneumoniae infections.

Impact of the ST101 clone on fatality among patients with colistin-resistant Klebsiella pneumoniae infection

Objectives

We describe the molecular characteristics of colistin resistance and its impact on patient mortality.

Methods

A prospective cohort study was performed in seven different Turkish hospitals. The genotype of each isolate was determined by MLST and repetitive extragenic palindromic PCR (rep-PCR). Alterations in mgrB were detected by sequencing. Upregulation of pmrCAB, phoQ and pmrK was quantified by RT-PCR. mcr-1 and the genes encoding OXA-48, NDM-1 and KPC were amplified by PCR.

Results

A total of 115 patients diagnosed with colistin-resistant K. pneumoniae (ColR-Kp) infection were included. Patients were predominantly males (55%) with a median age of 63 (IQR 46-74) and the 30 day mortality rate was 61%. ST101 was the most common ST and accounted for 68 (59%) of the ColR-Kp. The 30 day mortality rate in patients with these isolates was 72%. In ST101, 94% (64/68) of the isolates had an altered mgrB gene, whereas the alteration occurred in 40% (19/47) of non-ST101 isolates. The OXA-48 and NDM-1 carbapenemases were found in 93 (81%) and 22 (19%) of the total 115 isolates, respectively. In multivariate analysis for the prediction of 30 day mortality, ST101 (OR 3.4, CI 1.46-8.15, P = 0.005) and ICU stay (OR 7.4, CI 2.23-29.61, P = 0.002) were found to be significantly associated covariates.

Conclusions

Besides ICU stay, ST101 was found to be a significant independent predictor of patient mortality among those infected with ColR-Kp. A significant association was detected between ST101 and OXA-48. ST101 may become a global threat in the dissemination of colistin resistance and the increased morbidity and mortality of K. pneumoniae infection.

The state of the immune system in abdominal sepsis

AIM

To evaluate the prognostic value of cytokine profile, phagocytosis activity indices, endotoxin concentration and activity in blood in gram-negative sepsis.

MATERIALS AND METHODS

78 patients with abdominal sepsis were included in a one-center prospective cohort study, of them 45 died. All the patients were evaluated for the concentration of circulating cytokines (TNF-α, IFN-γ, IL-6, IL-8, IL-10), cellular molecules (CD3, CD45RO, CD95 and HLA-DR), bactericidal and phagocytic activity of neutrophils and endotoxin (lipopolysaccharide) level in peripheral blood.

RESULTS

The concentrations of all cytokines were slightly lower in the survivors. Significant differences were noted for TNF-α (p=0.001), IL-6 (p=0.001), and IL-8 (p=0.007). The expression of HLA-DR molecules was slightly higher (p=0.055), and CD95 was lower (p=0.146) in survivors than in the dead. However, the differences have not reached the required level of statistical significance. The phagocytic (p&lt;0.001) and bactericidal activity (р=0.002 for stimulated activity and p=0.001 for spontaneous activity) of neutrophils is significantly different. In survived patients, we noted large values of stimulated bactericidal activity and phagocytic index than the dead. Level of spontaneous activity in survivors was lower. In subsequently deceased patients, the level of endotoxin load was higher than in the surviving patients: level of lipopolysaccharide concentration (p=0.002), endotoxin activity (p=0.032) and neutrophils activity (p=0.028).

CONCLUSION

Evaluation of cytokine levels is informative, but due to the high spread of indicators in different patients, should be carried out in the dynamics. The most informative prognostic parameters in sepsis are the concentration and activity of lipopolysaccharides (endotoxin), phagocytic and bactericidal activity of neutrophils. The EAA (endotoxin activity assay) assessment should be conducted in conjunction with the neutrophil &quot;response&quot; assessment.

Pooled prevalence and trends of antimicrobial resistance in Pseudomonas aeruginosa clinical isolates over the past 10 years in Turkey: A meta-analysis

OBJECTIVES

This meta-analysis aimed to evaluate the current prevalence and trends over the past 10 years of Pseudomonas aeruginosa (P. aeruginosa) antimicrobial resistance. Two researches independently searched two national (ULAKBİM, Türk Medline) and two international databases (PubMed, Web of Science) to identify studies on P. aeruginosa resistance to antimicrobials from 2007 to 2017.

METHODS

Homogeneity across studies was assessed using Cochrane guidelines, and total variability due to between-study variations was reflected in the I² index. A random effects model was developed to estimate the antimicrobial resistance rates and their corresponding 95% CI. Pooled antibiotic resistance rates between 2007-2011 and 2012-2016 were compared to calculate the change in antibiotic resistance over time. Electronic searches with MeSH terms and text words identified 1017 papers. After applying exclusion and inclusion criteria, 45 articles were selected.

RESULTS

Pooled resistance prevalence of P. aeruginosa to piperacillin-tazobactam, ceftazidime, cefepime, meropenem, imipenem, ciprofloxacin, gentamicin, amikacin, tobramycin and colistin were 33.9%, 38.6%, 35.6%, 30.1%, 28.0%, 30.7%, 28.2%, 17.8%, 15.7% and 2.2%, respectively. The resistance rates of piperacillin, piperacillin-tazobactam, imipenem, meropenem, amikacin and colistin significantly increased in the second 5 years (P<0.05); however, gentamicin, tobramycin and ciprofloxacin resistance rates significantly decreased (P<0.05). Comparing the resistance rates between the isolates of intensive care unit (ICU) patients and non-ICU patients, meropenem and piperacillin-tazobactam resistance in ICU isolates were significantly higher than non-ICU (P<0.05).

CONCLUSIONS

These results suggest that antibiotic resistance is high in P. aeruginosa and the trends in antimicrobial resistance continue to increase, mainly in carbapenems and penicillins, in Turkey.

Risk Factors Affecting Patterns of Antibiotic Resistance and Treatment Efficacy in Extreme Drug Resistance in Intensive Care Unit-Acquired Klebsiella Pneumoniae Infections: A 5-Year Analysis

BACKGROUND We investigated the factors affecting antibiotic resistance in the intensive care unit (ICU)-related hospital-acquired infections caused by Klebsiella pneumoniae (KP-HAI) and the effects of antibiotics used for high-level antibiotic resistance on patient survival. MATERIAL AND METHODS This retrospective study was performed at the adult ICU of Bezmialem Vakif University Hospital. Patients who were followed up between 01 January 2012 and 31 May 2017 were evaluated. Each KP strain was categorized according to resistance patterns and analyzed. The efficiency of antibiotic therapy for highly-resistant KP-HAI was determined by patients' lifespans. RESULTS We evaluated 208 patients. With the prior use of carbapenem, antibiotics against resistant Gram-positives, and tigecycline, it was observed that the resistance rate of the infectious agents had a significant increase. As the resistance category increases, a significant decrease was seen in the survival time. We observed that if the treatment combination included trimethoprim-sulfamethoxazole, the survival time became significantly longer, and tigecycline-carbapenem-colistin and tigecycline-carbapenem combination patients showed significantly shorter survival times. CONCLUSIONS When the resistance increases, delays will occur in starting suitable and effective antibiotic treatment, with increased sepsis frequency and higher mortality rates. Trimethoprim-sulfamethoxazole can be an efficient alternative to extend survival time in trimethoprim-sulfamethoxazole-susceptible KP infections that have extensive drug resistance.

An in-depth analysis of nosocomial bloodstream infections due to Gram-negative bacilli: clinical features, microbiological characteristics and predictors of mortality in a 1 year, prospective study in a large tertiary care Italian hospital

BACKGROUND

Bloodstream infections (BSI) due to Gram negative bacilli (GNB) represent a major concern among nosocomial infections, since they are noticeably associated with a high mortality rates, increase of healthcare costs and prolongation of hospital stay.

METHODS

Over a 12-month period (2014-2015) all the adult patients admitted to a university-based Italian hospital were monitored for development of BSIs due to GNB. Multiple logistics regression models were performed to assess the impact of patients' risk factors on the in-hospital and 14-day mortality.

RESULTS

During the study period 208 patients were diagnosed with at least a BSI due to a Gram negative species for an incidence rate of 12.8 cases/1,000 admissions (95%CI: 11.2-14.7). Multivariate analyses showed that multiple organ dysfunctions along with immune deficit and inadequate therapy in the first 48hrs were associated with a higher risk of death.

CONCLUSIONS

A thorough evaluation of both immune status and organ dysfunction at the onset of septic events, along with adequate antimicrobial therapy appear to be the most reliable factors in predicting the outcome in these infections. SOFA score can be efficaciously substituted to the single organ dysfunctions analysis in predicting mortality after these events.

Implementation of an antimicrobial stewardship program for patients with febrile neutropenia

BACKGROUND

We aimed to describe the effectiveness of our standardized protocol for febrile neutropenia (FN), which was targeted to minimize unintended outcomes and reduce antimicrobial consumption.

METHODS

The study was performed in a private hospital with 300 beds. We included all adult hematologic and oncologic cancer inpatients admitted between January 1, 2015-December 31, 2015, and January 1, 2016-May 31, 2017. The outcomes of the study were fatality, infections, and adherence to the antimicrobial stewardship program (ASP).

RESULTS

We included 152 FN attacks of 95 adult inpatients from hematology and oncology wards; of these, 43% were women, and the median age was 57 years. The case fatality rate was 30% in the pre-ASP period and decreased to 11% in the post-ASP period (P = .024). The appropriate adding or changing (P = .006) and appropriate continuation or de-escalation or discontinuation of antimicrobials improved (P < .001). In the post-ASP period, Staphylococcus spp infections (from 22% to 8%, P = .02) and gram-negative infections decreased (from 43% to 20%, P = .003). In the multivariate analysis, appropriate continuation or de-escalation or discontinuation was increased in the post-ASP period (odds ratio [OR], 4.3; 95% confidence interval [CI], 1.82-10.41; P = .001), and gram-positive infections were decreased (OR, 0.32; 95% CI, 0.11-0.95, P = .041). Vancomycin and fluoroquinolone use decreased significantly.

CONCLUSIONS

After implementation of the ASP, the case fatality rate among the patients with FN decreased. Appropriate antimicrobial use increased and overall antimicrobial consumption was reduced. Bacterial infections and Candida infections decreased.

Rapid emergence of colistin resistance and its impact on fatality among healthcare-associated infections

This article describes the emergence of resistance and predictors of fatality for 1556 cases of healthcare-associated Gram-negative bloodstream infection in 2014 and 2015. The colistin resistance rate in Klebsiella pneumoniae was 16.1%, compared with 6% in 2013. In total, 660 (42.4%) cases were fatal. The highest fatality rate was among patients with Acinetobacter baumannii bacteraemia (58%), followed by Pseudomonas aeruginosa (45%), Klebsiella pneumoniae (41%), Enterobacter cloacae (32%) and Escherichia coli (28%). On multi-variate analysis, the minimum inhibitory concentrations for carbapenems [odds ratio (OR) 1.02, 95% confidence interval (CI) 1.01-1.04; P = 0.002] and colistin (OR 1.1, 95% CI 1.03-1.17; P = 0.001) were found to be significantly associated with fatality.

Repeat gram-negative hospital-acquired infections and antibiotic susceptibility: A systematic review

Repeat HAIs among frequently hospitalized patients may be contributing to the high rates of antibiotic resistance seen in gram-negative bacteria (GNB) in hospital settings. This systematic review examines the state of the literature assessing the association between repeat GNB HAIs and changes in antibiotic susceptibility patterns. A systematic search of English language published literature was conducted to identify studies in peer-reviewed journals from 2000 to 2015. Studies must have assessed drug resistance in repeat GNB infections longitudinally at the patient level. Two researchers independently reviewed search results for papers meeting inclusion criteria and extracted data. Risk of bias was assessed using a modified quality assessment tool based on the Checklist for Measuring Study Quality and the Quality Assessment Checklist for Cases Series. From 3385 articles identified in the search, seven met inclusion criteria. Five reported lower antibiotic susceptibility in repeated infections, one found a change but did not specify in which direction, and one reported no change. All studies were of low to average quality. Despite the dearth of studies examining repeat GNB infections, evidence suggests that repeat infections result in lower antibiotic susceptibility among hospitalized patients. Larger scale studies with strong methodology are warranted.

Carbapenem-resistant Enterobacteriaceae in the community: a scoping review

Carbapenem antibiotics are used as a last resort to treat serious Gram-negative bacteria (GNB) infections; however, carbapenemase-producing strains of GNB have emerged as a major source of resistance. Owing to the highly transmissible nature of plasmid-borne carbapenemases, numerous reports have warned about the likely spread into the community from healthcare settings. Since the prevalence of carbapenem-resistant Enterobacteriaceae (CRE) in the community is largely unknown, we conducted a scoping review of the literature to assess the percentage of CRE isolates that could be associated with the community. Initially, 361 studies were assessed and 15 met the inclusion criteria. Although 5 studies (33.3%) found no community-associated CRE, the remaining 10 studies identified percentages ranging from 0.04% to 29.5% of either community-associated or community-onset CRE among their samples, with US-based studies alone ranging from 5.6 to 10.8%. The presence of CRE in the community poses an urgent public health threat.