Risk factors and outcomes for the acquisition of carbapenem-resistant Gram-negative bacillus bacteremia: A retrospective propensity-matched case control study

Epidemiology, Clinical, and Microbiological Characteristics of Multidrug-Resistant Gram-Negative Bacteremia in Qatar

Antimicrobial resistance is a global healthcare threat with significant clinical and economic consequences peaking at secondary and tertiary care hospitals where multidrug-resistant Gram-negative bacteria (MDR GNB) lead to poor outcomes. A prospective study was conducted between January and December 2019 for all invasive bloodstream infections (BSIs) secondary to MDR GNB in Qatar identified during routine microbiological service to examine their clinical, microbiological, and genomic characteristics. Out of 3238 episodes of GNB BSIs, the prevalence of MDR GNB was 13% (429/3238). The predominant MDR pathogens were Escherichia coli (62.7%), Klebsiella pneumoniae (20.4%), Salmonella species (6.6%), and Pseudomonas aeruginosa (5.3%), while out of 245 clinically evaluated patients, the majority were adult males, with the elderly constituting almost one-third of the cohort and with highest observed risk for prolonged hospital stays. The risk factors identified included multiple comorbidities, recent healthcare contact, previous antimicrobial therapy, and admission to critical care. The in-hospital mortality rate was recorded at 25.7%, associated with multiple comorbidities, admission to critical care, and the acquisition of MDR Pseudomonas aeruginosa. Resistant pathogens demonstrated high levels of antimicrobial resistance but noticeable susceptibility to amikacin and carbapenems. Genomic analysis revealed that Escherichia coli ST131 and Salmonella enterica ST1 were the predominant clones not observed with other pathogens.

Increasing trend of healthcare-associated infections due to vancomycin-resistant Enterococcus faecium (VRE-fm) paralleling escalating community-acquired VRE-fm infections in a medical center implementing strict contact precautions: An epidemiologic and pathogenic genotype analysis and its implications

OBJECTIVE

To clarify whether there were clandestine intra-hospital spreads of vancomycin-resistant Enterococcus faecium (VRE-fm) isolates that led to specific strain of VRE lingering in the hospital and/or developing outbreaks that rendered a progressively increasing trend of healthcare-associated infections due to VRE-fm (VRE-fm-HAIs).

SETTING

Despite implementing strict contact precautions for hospitalized patients with VRE-fm-infection/colonization, number of VRE-fm-HAIs in a medical centre in southern Taiwan were escalating in 2009-2019, paralleling an increasing trend of community-acquired VRE-fm- infections.

METHODS

We analyzed epidemiologic data and genotypes of non-duplicate VRE-fm isolates each grown from a normally sterile site of 89 patients between December 2016 and October 2018; multilocus sequence typing (MLST) and pulse-field gel electrophoresis (PFGE) typing were performed.

RESULTS

Totally 13 sequence types (STs) were found, and the 3 leading STs were ST17 (44％), ST78 (37％), and ST18 (6％); 66 pulsotypes were generated by PFGE. Four VRE-fm isolates grouped as ST17/pulsotype S, 2 as ST17/pulsotype AS, 2 as ST17/pulsotype AU, and 3 as ST78/pulsotype V grew from clinical specimens sampled less than one week apart from patients staying at different wards/departments and/or on different floors of the hospital.

CONCLUSIONS

Despite possible small transitory clusters of intra-hospital VRE-fm spreads, there was no specific VRE-fm strain lingering in the hospital leading to increasing trend of VRE-fm-HAIs during the study period. Strict contact precautions were able to curb intra-hospital VRE-fm spreads, but unable to curb the increasing trend of VRE-fm-HAIs with the backdrop of progressively increasing VRE-fm-infections/colorizations in the community.

Multidrug-resistant gram-negative bacteria in patients with COVID-19: An epidemiological and clinical study

Epidemiological data regarding the incidence of secondary multidrug-resistant (MDR) Gram-negative infection in patients with coronavirus disease (COVID-19) in Brazil are still ambiguous. Thus, a case-control study was designed to determine factors associated with the acquisition of MDR Gram-negative bacteria (GNB) in patients with and without COVID-19 and describe the mortality rates and clinical features associated with unfavorable outcomes. In total, we assessed 280 patients admitted to Brazilian intensive care units from March/2020 to December/2021. During the study, 926 GNB were isolated. Out of those, 504 were MDR-GNB, representing 54.4% of the resistance rate. In addition, out of 871 patients positive for COVID-19, 73 had secondary MDR-GNB infection, which represented 8.38% of documented community-acquired GNB-MDR infections. The factors associated with patients COVID-19-MDR-GNB infections were obesity, heart failure, use of mechanical ventilation, urinary catheter, and previous use of β-lactams. Several factors associated with mortality were identified among patients with COVID-19 infected with MDR-GNB, including the use of a urinary catheter; renal failure; and the origin of bacterial cultures such as tracheal secretion, exposure to carbapenem antibiotics, and polymyxin. Mortality was significantly higher in patients with COVID-19-MDR-GNB (68.6%) compared to control groups, where COVID-19 was 35.7%, MDR-GNB was 50%, and GNB was 21.4%. Our findings demonstrate that MDR-GNB infection associated with COVID-19 has an expressive impact on increasing the case fatality rate, reinforcing the importance of minimizing the use of invasive devices and prior exposure to antimicrobials to control the bacterial spread in healthcare environments to improve the prognosis among critical patients.

Synthesis of Graphene Quantum Dot Magnesium Hydroxide Nanocomposites and Investigation of Their Antioxidant and Antimicrobial Activities

In this paper, we synthesized graphene quantum dots magnesium hydroxide nanocomposites (GQDs/Mg(OH)₂). The synthesized nanocomposites were characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Malvern Zetasizer. The antimicrobial and antioxidant properties of the obtained GQDs/Mg(OH)₂ nanocomposites were investigated. GQDs/Mg(OH)₂ nanocomposites have MIC values of 15.625 μg/mL against fungi (C. metapsilosis and C. parapsilosis) and 62.5 μg/mL against Gram (+) (S. pneumonia and E. faecalis) and Gram (-) (E. coli). The synthesized GQDs/Mg(OH)₂ nanocomposites showed moderate antioxidant activity. The results showed that at 100-µg/mL GQDs/Mg(OH)₂ nanocomposite concentration, the H₂O₂ scavenging activity was 62.18%.

Risk Factors for Infection With Multidrug-Resistant Gram-Negative Bacteria in a Tertiary Care Hospital in Saudi Arabia: A Case-Control Study

Background The increase in the incidence of multidrug-resistant (MDR) organisms especially Gram-negative bacteria (GNB) in healthcare facilities is a serious cause of concern. This study identified risk factors for the infection with these MDR GNB, such as Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli to inform healthcare workers about strategies for their containment. Methods A case-control study was carried out at a tertiary care hospital where 100 patients with healthcare-associated infections (infections arising 48 hours after admission) caused by MDR GNB were compared with two control groups, i.e., 100 patients with healthcare-associated infections caused by non-MDR GNB (not meeting the criteria of MDR) and 100 patients without infection caused by GNB. MDR bacteria were defined as the ones that were non-susceptible to at least one antibiotic in three or more classes of antibiotics. The data were analyzed using descriptive statistics (frequency and percentage of categorical variables). Multivariate regression analysis was undertaken to identify significant predictors of MDR GNB. Odds ratios with 95% confidence intervals were calculated, and the level of significance was determined at p-value < 0.05. Results A total of 388 organisms were isolated during four months (January-April 2015) from 332 patients. Fifty-six (17%) of the patients were infected with more than one organism. Among the MDR bacteria, the most dominant MDR organism was A. baumannii (38%), followed by K. pneumoniae (31%), P. aeruginosa (20%), and E. coli (11%). Among the non-MDR organisms, the most dominant was P. aeruginosa (47%), followed by E. coli (32%), K. pneumoniae (18%), and A. baumannii (3%). Patients with MDR organisms compared with the first control group (patients with non-MDR organisms) showed that prior antibiotic use (p-value: 0.001), intensive care unit (ICU) admission (p-value: 0.001), and indwelling medical devices (p-value: 0.005) were significant risk factors for MDR infections. It was also found that the risk factors for MDR GNB infection were the same in the second control group (patients without infection): prior antibiotic use (p-value: 0.002), ICU admission (p-value: 0.001), and indwelling medical devices (p-value: 0.03). Based on the comparison of the two control groups, prolonged hospital stays of more than five days (p-value: 0.001), immunosuppressive therapy (p-value: 0.02), and over 60 years of age (p-value: 0.02) were significant risk factors for non-MDR infection. Conclusion  The risk factors identified in our study provide guidance to healthcare workers for the prevention and containment of MDR GNB.

Carbapenem Resistance in Gram-Negative Bacteria: A Hospital-Based Study in Egypt

Background and Objectives: The global spread of carbapenem resistance and the resulting increase in mortality forced the World Health Organization (WHO) to claim carbapenem-resistant enterobacteriaceae (CRE) as global priority pathogens. Our study aimed to determine the prevalence of carbapenemase-encoding genes and major plasmid incompatibility groups among Gram-negative hospital-based isolates in Egypt. Material and Methods: This cross-sectional study was carried out at Mansoura University Hospitals over 12 months, from January to December 2019. All the isolates were tested for carbapenem resistance. The selected isolates were screened by conventional polymerase chain reaction (PCR) for the presence of carbapenemase genes, namely bla_KPC, bla_IMP, bla_VIM, and bla_NDM-1. PCR-based plasmid replicon typing was performed using the commercial PBRT kit. Results: Out of 150 isolates, only 30 (20.0%) demonstrated carbapenem resistance. Klebsiella pneumoniae was the most resistant of all isolated bacteria, and bla_NDM was the predominant carbapenemases gene, while the most prevalent plasmid replicons were the F replicon combination (FIA, FIB, and FII) and A/C. Plasmids were detected only in Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae, and Pseudomonas aeruginosa. Remarkably, we found a statistically significant association between carbapenemase genes and plasmid replicons, including bla_NDM, IncA/C, and IncX. Conclusions: Our study demonstrated an alarming rise of plasmid-mediated carbapenem-resistant bacteria in our locality. The coexistence of resistance genes and plasmids highlights the importance of a targeted antibiotic surveillance program and the development of alternative therapeutic options at the local and international levels. Based on our results, we suggest a large-scale study with more Enterobacteriaceae isolates, testing other carbapenemase-encoding genes, and comparing the replicon typing method with other plasmid detection methods. We also recommend a national action plan to control the irrational use of antibiotics in Egypt.

Development and validation of nomograms for predicting the risk probability of carbapenem resistance and 28-day all-cause mortality in gram-negative bacteremia among patients with hematological diseases

Objectives

Gram-negative bacteria (GNB) bloodstream infections (BSIs) are the most widespread and serious complications in hospitalized patients with hematological diseases. The emergence and prevalence of carbapenem-resistant (CR) pathogens has developed into a considerable challenge in clinical practice. Currently, nomograms have been extensively applied in the field of medicine to facilitate clinical diagnosis and treatment. The purpose of this study was to explore risk indicators predicting mortality and carbapenem resistance in hematological (HM) patients with GNB BSI and to construct two nomograms to achieve personalized prediction.

Methods

A single-center retrospective case-control study enrolled 244 hospitalized HM patients with GNB-BSI from January 2015 to December 2019. The least absolute shrinkage and selection operator (LASSO) regression analysis and multivariate logistic regression analysis were conducted to select potential characteristic predictors of plotting nomograms. Subsequently, to evaluate the prediction performance of the models, the prediction models were internally validated using the bootstrap approach (resampling = 1000) and 10-fold cross validation.

Results

Of all 244 eligible patients with BSI attributed to GNB in this study, 77 (31.6%) were resistant to carbapenems. The rate of carbapenem resistance exhibited a growing tendency year by year, from 20.4% in 2015 to 42.6% in 2019 (p = 0.004). The carbapenem resistance nomogram constructed with the parameters of hypoproteinemia, duration of neutropenia ≥ 6 days, previous exposure to carbapenems, and previous exposure to cephalosporin/β-lactamase inhibitors indicated a favorable discrimination ability with a modified concordance index (C-index) of 0.788 and 0.781 in both the bootstrapping and 10-fold cross validation procedures. The 28-day all-cause mortality was 28.3% (68/240). The prognosis nomogram plotted with the variables of hypoproteinemia, septic shock, isolation of CR-GNB, and the incomplete remission status of underlying diseases showed a superior discriminative ability of poorer clinical prognosis. The modified C-index of the prognosis nomogram was 0.873 with bootstrapping and 0.887 with 10-fold cross validation. The decision curve analysis (DCA) for two nomogram models both demonstrated better clinical practicality.

Conclusions

For clinicians, nomogram models were effective individualized risk prediction tools to facilitate the early identification of HM patients with GNB BSI at high risk of mortality and carbapenem resistance.

Treatments and Predictors of Mortality for Carbapenem-Resistant Gram-Negative Bacilli Infections in Malaysia: A Retrospective Cohort Study

This study evaluated the treatments, mortality rate and patient-related factors associated with mortality. This is a retrospective study involving hospitalised patients with infections caused by carbapenem-resistant Gram-negative bacilli (CR-GNB) in a tertiary hospital in Malaysia from January 2018 to June 2020. A clinical pharmacist reviewed patients' electronic records and collected the data according to a pre-designed form. Data were analysed using both descriptive and inferential tests. The study included 145 patients with CR-GNB infections including 77, 40 and 28 Acinetobacter baumannii, enterobacteriaceae and Pseudomonas aeruginosa, respectively. The mean age was 57.9 ± 15.8 years. Pneumonia (40.7%) and bacteremia (25.5%) were the most common infections. Meropenem (24.7%) and piperacillin-tazobactam (20.4%) were the most commonly used empiric antibiotics while colistin (63.3%) and amikacin (8.3%) were the most common definitive antibiotics. The mean duration before active antibiotics was 4.6 ± 3.3 days. Overall, the in-hospital mortality rate was 41.4%. Multivariate logistic regression analysis showed that intensive care unit (ICU) admission (adjusted odds ratio (AOR): 5.201; 95% confidence interval (CI): 1.603-16.872; p = 0.006), sepsis/septic shock (AOR: 3.430; 95% CI: 1.021-11.522; p = 0.049) and elevated serum creatinine (AOR: 2.752; 95% CI: 1.005-7.536; p = 0.049) were independently associated with mortality. The mortality rate among patients with CR-GNB infection is high. A high rate of inappropriate antibiotic use was observed, including combination antibiotic therapy and delays in starting active antibiotics. Mortality was significantly associated with ICU admission, sepsis/septic shock and elevated serum creatinine.

Bacteriological aspects of bacteremia in the intensive care unit of the Mohammed V Military Hospital: 10 months prospective study

Introduction

Bacteremia is responsible for high rates of morbidity and mortality. The increasing prevalence of multidrug-resistant (MDR) bacteria in intensive care units (ICU) is a growing concern. Hence, prior knowledge of bacterial epidemiology and resistance phenotypes is required to optimize these infections' management. The objective of this study was to determine the epidemiological profile of bacteremia in ICU settings, as well as the place occupied by MDR bacteria in these infections.

Methods

It is a prospective study carried out over 10 months on episodes of bacteremia in the ICU of Mohammed V Military Teaching Hospital (Rabat, Morocco). Microorganism growth was detected using fluorescent technology, species identification was based on morphological and biochemical characteristics. Antimicrobial susceptibility testing was performed following the recommendations of the Antibiogram Committee of the French Society of Microbiology (CA-SFM) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST).

Results

Among 504 hospitalized patients, sixty-one (12.1%) presented at least one episode of bacteremia. Forty patients (65.6% of bacteremic patients) presented at least one episode of bacteremia due to MDR bacteria. Male gender, cardiovascular diseases, diabetes and previous hospitalization were significant risk factors for the acquisition of MDR bacteremia. Isolated bacteria were mainly Gram-negative bacilli (GNB) (n = 62; 68.9%) dominated by Acinetobacter baumannii (n = 19; 21.1%) and Klebsiella pneumoniae (n = 16; 17.8%). MDR bacteria were represented by multi-resistant Acinetobacter baumannii (n = 19; 44.2%), extended-spectrum beta-lactamases-producing Enterobacterales (n = 9; 20.9%) and carbapenem-resistant Enterobacterales (n = 7; 16.3%). Carbapenems (n = 40; 65.6%), Aminoglycosides (n = 32; 52.5%) and Polypeptides (n = 24; 39.3%) were the most used antimicrobials. Mortality rates were 66.6% (n = 40) and 85% (n = 43) in patients with non MDR bacteremia and MDR bacteremia respectively.

Conclusion

Limiting the spread of MDR bacteria and improving the management of bacteremic patients require continuous monitoring of bacteremia as well as adapting the therapeutic and preventive strategy.

Epidemiological characteristics of carbapenem-resistant Enterobacteriaceae and carbapenem-resistant Acinetobacter baumannii in a tertiary referral hospital in Korea

Objectives

This study aimed to identify the epidemiological characteristics of patients with carbapenem-resistant Enterobacteriaceae and Acinetobacter baumannii (CRE/CRAB) isolates in a tertiary referral hospital in Korea.

Methods

We collected and analyzed data from 528 adults admitted to a tertiary referral hospital from August 1, 2018 to February 29, 2020. The CRE/CRAB isolates were confirmed as being present at the time of patients’ admission or acquired during hospitalization based on their medical records. The t-test, chi-square test, or Fisher exact test and stepwise multiple logistic regression were performed.

Results

While the proportion of community-acquired CRE/CRAB was low (6%), 20% of CRE/CRAB isolates were identified in patients at the time of hospitalization. The risk of CRAB isolation was positively associated with mechanical ventilator use (odds ratio [OR], 3.52; 95% confidence interval [CI], 1.96−6.33) and total parenteral nutrition use (OR, 3.64; 95% CI, 1.87−7.08).

Conclusion

Over 20% of CRE/CRAB isolates in a tertiary referral hospital in Korea were found at the time of patients’ admission. Furthermore, patients with mechanical ventilation and/or total parenteral nutrition tended to acquire CRAB more frequently. Thus, active surveillance for CRE/CRAB at the time of hospitalization is strongly required, particularly for patients who are expected to require mechanical ventilation or total parenteral nutrition.

Different Effects of Antibiotics on Klebsiella pneumoniae and Escherichia coli Resistance Induced by Antibiotics: A Retrospective Study from China

Objective: The main objective was to assess the correlation between antibiotic use and carbapenem-resistant Klebsiella pneumoniae (CRKP) and carbapenem-resistant Escherichia coli (CREC) induction by antibiotics. Materials and Methods: A retrospective cohort study was conducted from January 2017 to December 2020. This study included patients with K. pneumoniae and E. coli. Kaplan-Meier analysis and Cox proportional hazard model were used to estimate the hazard of carbapenem-resistant Enterobacterales (CRE), whereas restricted cubic spline regression was used to visualize the hazard of CRE by antibiotics at different doses. Results: Two thousand fifty-six K. pneumoniae patients and 3,243 E. coli patients were included. After Cox proportional hazard model analysis, carbapenems or 1st-cephalospoins or penicillin monotherapy, male and ICU admission were associated with CRKP. CREC was associated with quinolone monotherapy. Time-to-event analysis indicated that carbapenem, β-lactamase inhibitor mixtures, and quinolones were associated with higher 30-day CRKP hazards than other antibiotics (χ² = 33.670, p < 0.001). Further restricted cubic spline regression analysis found that the hazard of CRKP induction decreased with the increased dose of β-lactamase inhibitor mixtures, but there was no significant change in the hazard ratio of CRKP induction with the increased dose of quinolones. Moreover, there was an obvious characteristic of "parabolic curve" for the hazard of CREC induction due to β-lactamase inhibitor mixtures, and the hazard value gradually increased with the dose, reached the maximum at 24 g, and finally gradually decreased from 26 g. Conclusions: Rational use of antibiotics should be implemented and antimicrobial stewardship policies should be adjusted according to the characteristics of each hospital.

OUP accepted manuscript

Background

The treatment options for infections caused by MDR Gram-negative bacteria have been limited, especially for infections caused by bacteria that produce carbapenemases and/or ESBLs. Ceftolozane/tazobactam is a cephalosporin/β-lactamase inhibitor developed to treat Gram-negative bacteria.

Methods

Ceftolozane/tazobactam and 14 comparators (amikacin, aztreonam, cefepime, cefotaxime, cefoxitin, ceftazidime, ceftriaxone, ciprofloxacin, colistin, ertapenem, imipenem, levofloxacin, meropenem and piperacillin/tazobactam) were evaluated against Pseudomonas aeruginosa and Enterobacterales isolates collected from Kuwait and Oman (n = 606) during 2016–17. In addition, further analysis of resistance mechanisms to ceftolozane/tazobactam was done utilizing WGS. Non-susceptible isolates from ceftolozane/tazobactam surveillance were selected for analysis. Overall, 35 strains underwent WGS.

Results

Among isolates from Kuwait, susceptibility of P. aeruginosa, Escherichia coli and Klebsiella pneumoniae to ceftolozane/tazobactam was 79.8%, 95.7% and 87.5%, respectively, and from Oman was 92.3%, 93.1% and 88.5%, respectively. No P. aeruginosa with a ceftolozane/tazobactam MIC <32 mg/L encoded β-lactamases besides normal chromosomal enzymes (PDC variants or OXA-50-like) whereas all but one P. aeruginosa isolate with MIC >32 mg/L encoded either MBLs (60%), VEB-1 (19%) or additional OXAs (3.7%).

Conclusions

Colistin followed by ceftolozane/tazobactam showed the greatest activity against P. aeruginosa. Enterobacterales showed more susceptibility to ceftolozane/tazobactam than to piperacillin/tazobactam, but meropenem and colistin showed better activity.

Comparison of Risk Factors and Outcomes in Carbapenem-Resistant and Carbapenem-Susceptible Gram-Negative Bacteremia

Background:

Carbapenem-resistant Gram-negative bacteremia (CR-GNB) is seen with increasing frequency and result in high mortality. The aim of this study was to compare the risk factors and results of carbapenem-resistant and carbapenem-susceptible Gram-negative bacteremia and to determine the factors related to mortality.

Methods:

The study was conducted as a retrospective observational comparative case series between June 2016 and November 2017 in Şişli Hamidiye Etfal Training and Research Hospital. The patients were divided into two groups as carbapenem-susceptible and carbapenem-resistant according to antibiotic susceptibility data of blood cultures. The risk factors for the development of carbapenem resistance, length of hospital stay, mortality rates, and mortality related factors were investigated between these two groups.

Results:

Two hundred and eleven cases were included in the study. Of these cases, 54 were resistant to carbapenem and 157 were susceptible to carbapenem. Mortality occurred in 60 (28.4%) patients. The 14 and 28 day mortality rates of patients with carbapenem resistance were significantly higher than those without carbapenem resistance. There was no statistically significant difference between two groups in length of stay in the hospital after bacteremia. Pittsburgh bacteremia score, cardiovascular disease, urinary catheterization, and inappropriate empirical antibiotic therapy were the most significant risk factors for mortality.

Conclusions:

Carbapenem resistance is associated with increased mortality and inappropriate empirical antibiotic treatment increases mortality. Therefore, patients should be evaluated for risk factors in predicting CR-GNB and treatment for resistant pathogens should be applied in appropriate patients.

Risk factors and mortality associated with multidrug-resistant gram-negative bacterial infection in adult patients with abdominal surgery

BACKGROUND

Multidrug-resistant (MDR) gram-negative bacterial (GNB) infections remain a significant cause of morbidity and mortality among surgical patients. The objective of our study was to recognize the risk factors for MDR GNB infection in patients with abdominal surgery and determine the predictors independently associated with death.

METHODS

From 2010 to 2017, a retrospective cohort study was conducted among patients with abdominal surgery admitted in surgical intensive care unit (ICU). Patients with GNB infections were included for analyses.

RESULTS

A total of 364 patients with abdominal surgery experienced GNB infections, among them, 117 (32.1%) were MDR GNB infection. Of 133 MDR GNB isolates, the most frequent isolate was Escherichia coli (45.1%). Patients with MDR GNB infection had significantly longer ventilator days and hospital stay, as well as higher 30-day and in-hospital mortality compared to non-MDR GNB patients. Multivariable analysis showed longer length of pre-ICU stay, surgical re-exploration, receipt of group 2 carbapenems (e.g. imipenem, meropenem and doripenem) and fluoroquinolones, and higher total bilirubin were independent risk factors for the acquisition of MDR GNB infection. Predictors for 30-day mortality among patients with MDR GNB infection were chronic kidney disease, receipt of group 2 carbapenems and inappropriate empirical antimicrobial therapy.

CONCLUSIONS

This study provides important information about the risk factors for subsequent MDR GNB infection and 30-day mortality among the patients with abdominal surgery.

Duration of antimicrobial therapy for Gram-negative infections

PURPOSE OF REVIEW

The potential benefits on antimicrobial resistance emergence, incidence of antibiotic-related adverse effects, and health costs have pushed to shorten therapeutic courses for Gram-negative bacilli (GNB) infections. However, the safety of this approach is still under investigation. This review gathers recent contributions to the evaluation of the impact on antimicrobial resistance and clinical outcome of shorter therapeutic courses against GNB infections, and highlights data on the modern approach of adjustable antibiotic duration.

RECENT FINDINGS

Recent advances include data on the safety of 7-day treatment of uncomplicated Enterobacteriaceae bloodstream infections with favorable early 48-h evolution. A promising innovative approach with individualized treatment duration arises, supported by recently published results on GNB bacteremia evaluating fixed antibiotic durations and an adaptive antibiotic duration driven by blood levels of C-reactive protein.

SUMMARY

Recent literature illustrates a strong trend towards shortened antibiotic durations in GNB infections, illustrated by lately published data in GNB bacteremia and ongoing studies in GNB ventilator-associated pneumonia. However, short antibiotic course for specific situations, such as immunodeficiency, drug-resistance, and inadequate source control should be handled with caution because of lack of supportive data.

Rapid Determination of Antibiotic Resistance in Klebsiella pneumoniae by a Novel Antibiotic Susceptibility Testing Method Using SYBR Green I and Propidium Iodide Double Staining

Due to the broad-spectrum antibiotic usage and empirical treatments, the pathogenic bacterium, Klebsiella pneumoniae, has shown extremely high detection rates at hospitals with an increasing antibiotic resistance. Therefore, rapid detection of the antibiotic resistance is urgently required and essential for effective treatments. In this study, we evaluated the performance of a newly developed method for ultra-rapid detection of antibiotic resistance in 30–60 min in K. pneumoniae by using the SYBR Green I and propidium iodide (PI) staining. A total of 100 clinical isolates were tested for antibiotic resistance using four different antibiotics (ceftriaxone, cefepime, meropenem, and ciprofloxacin). The results showed that the SYBR Green I/PI rapid antibiotic susceptibility test (AST) could reliably detect antibiotic resistance to the four drugs in 60 min, and the results were highly concordant with the conventional AST (i.e., Kirby-Bauer method and broth microdilution method) for detection of ceftriaxone, cefepime, meropenem, and ciprofloxacin resistance with a high accuracy of 99, 96, 96, and 93%, respectively. Therefore, the rapid AST established in our study helps to enable targeted therapy to save lives and reduce the empirical use of antibiotics and ultimately the health and economic burdens of antibiotic resistance.

Formulation and evaluation of injectable dextran sulfate sodium nanoparticles as a potent antibacterial agent

The purpose of this study was to develop a novel nano antibacterial formulation of dextran sulfate sodium polymer. The dextran sulfate sodium (DSS) nanoparticles were formulated with gelation technique. The nanoparticles exhibited significant physicochemical and effective antibacterial properties, with zeta potential of − 35.2 mV, particle size of 69.3 z d nm, polydispersity index of 0.6, and percentage polydispersity of 77.8. The DSS nanoparticles were stable up to 102 °C. Differential scanning calorimetry revealed an endothermic peak at 165.77 °C in 12.46 min, while XRD analysis at 2θ depicted various peaks at 21.56°, 33.37°, 38.73°, 47.17°, 52.96°, and 58.42°, indicating discrete nanoparticle formation. Antibacterial studies showed that the DSS nanoparticles were effective against Gram-positive and Gram-negative bacteria. The minimum inhibitory concentrations of DSS nanoparticles for Bacillus subtilis (B. subtilis), Staphylococcus aureus (S. aureus), Streptococcus pyogenes (S. pyogenes), Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Klebsiella pneumoniae (K. pneumoniae) and Proteus vulgaris (P. vulgaris) were 150, 200, 250, 150, 200, 250, 250 µg/mL, respectively. The antibacterial effects of DSS nanoparticles were in the order E. coli (26 ± 1.2 mm) at 150 µg/mL > S. pyogenes (24.6 ± 0.8 mm) at 250 µg/mL > B. subtilis (23.5 ± 2 mm) at 150 µg/mL > K. pneumoniae (22 ± 2 mm) at 250 µg/mL > P. aeruginosa (21.8 ± 1 mm) at 200 µg/mL > S. aureus (20.8 ± 1 mm) at 200 µg/mL > P. vulgaris (20.5 ± 0.9 mm) at 250 µg/mL. These results demonstrate the antibacterial potency of DSS injectable nanoparticles.

Early Screening of Risk for Multidrug-Resistant Organisms in the Emergency Department in Patients With Pneumonia and Early Septic Shock: Single-Center, Retrospective Cohort Study

OBJECTIVES

Pneumonia is the fourth leading cause of death globally, with rapid progression during sepsis. Multidrug-resistant organisms (MDROs) are becoming more common with some healthcare-associated pneumonia events. Early detection of MDRO risk improves the outcomes; however, MDROs risk in pneumonia with sepsis is unknown. This study investigated the disease outcomes of pneumonia with septic shock in patients admitted in the emergency department (ED) intensive care unit (ICU), a population with a high prevalence of MDROs, after early screening of MDROs risk.

METHODS

In this retrospective cohort study, patients with pneumonia and early septic shock (n = 533) admitted to the ED at the Taipei Tzu Chi Hospital from 2013 to 2019 were selected. The study population was divided into four subgroups after the MDROs risk and screening procedure were completed within 1 or 6 h of admission. ICU mortality and multidrug antibiotic therapy were compared.

RESULTS

The high-risk MDROs groups had higher percentage of P aeruginosa than the low-risk group. Furthermore, the appropriate ED first antibiotics were higher in the 1-h subgroup than in the 6-h subgroup of the high-risk MDROs group. In multivariate analysis, the 6-h high-risk MDROs group had an adjusted odds ratio of 7.191 (95% CI: 2.911-17.767, P < 0.001) and 2.917 (95% CI: 1.456-5.847, P = 0.003) for ICU mortality and multidrug therapy in the ICU, respectively, after adjusting for other confounding factors.

CONCLUSIONS

MDRO screening within 1 h is recommended following admission of patients with pneumonia and early septic shock in the ED, especially in areas with a high prevalence of MDROs.

Fosfomycin Dosing Regimens based on Monte Carlo Simulation for Treated Carbapenem-Resistant Enterobacteriaceae Infection

BACKGROUND

Infections by Carbapenem-Resistant Enterobacteriaceae (CRE) remain a leading cause of death in critically ill patients. Fosfomycin has been regarded as an alternative therapy for treatment of infections caused by CRE organisms. The purpose of this study is to evaluate clinical outcomes amongst patients with CRE infection who are receiving a fosfomycin dosing regimen using a Monte Carlo simulation and fosfomycin minimum inhibitory concentration (MIC).

MATERIALS AND METHODS

Fosfomycin MIC was defined by the E-test method. We used Fosfomycin pharmacokinetic parameters from a previously published study. The percent of the time period in which the drug concentration exceeded the MIC, or %T>MIC, used in this study were determined to be 70% of T>MIC and 100% of T>MIC, respectively. All dosing regimens were estimated for the probability of target attainment using a Monte Carlo simulation.

RESULTS

In this study, we found the MIC's of fosfomycin against CRE isolates ranged from 8 mg/L to 96 mg/L. The total daily dose of fosfomycin ranged from 16 - 24 g and was administered utilizing various fosfomycin dosing regimens to achieve the pharmacokinetic/pharmacodynamic (PK/PD) target in pathogens with a MIC of 32 mg/L for 70%T>MIC and a MIC of 12 mg/L for 100%T>MIC, respectively. For the twelve patients who received the recommended fosfomycin dosing regimen, eleven achieved bacterial eradication for a microbiological cure rate of 91%; and of those patients achieving eradication, two died despite having negative cultures for CRE; the one remaining patient had bacterial persistence. The most commonly observed adverse drug reactions were hypernatremia (3 cases) and hypokalemia (3 cases) and acute kidney injury (3 cases).

CONCLUSION

Our findings suggest fosfomycin has tended to good efficacy when using dosing regimens that achieve the PK/PD target. Nonetheless, further validation of these regimens in larger populations is needed.

Predictive factors for sepsis by carbapenem resistant Gram-negative bacilli in adult critical patients in Rio de Janeiro: a case-case-control design in a prospective cohort study

Background

Studies have investigated risk factors for infections by specific species of carbapenem-resistant Gram-negative bacilli (CR-GNB), but few considered the group of GNB species and most of them were performed in the setting of bacteremia or hospital infection. This study was implemented to identify risk factors for sepsis by CR- and carbapenem-susceptible (CS) GNB in intensive care unit (ICU) patients to improve management strategies for CR-GNB sepsis.

Methods

We developed a case-case-control study from a prospective cohort of patients with systemic inflammatory response syndrome (SIRS), sepsis-2 or sepsis-3 criteria in which blood and other sample cultures were collected and antimicrobial therapy was instituted, in an adult clinical-surgical ICU, at tertiary public hospital in Rio de Janeiro, from August 2015 through March 2017.

Results

Among the total of 629 ICU admissions followed by 7797 patient-days, after applying inclusion and exclusion criteria we identified 184 patients who developed recurrent or single hospital-acquired sepsis. More than 90% of all evaluable cases of sepsis and 87% of control group fulfilled the modified sepsis-3 definition. Non-fermenting bacilli and ventilator-associated pneumonia predominated as etiology and source of CR-GNB sepsis. While Enterobacteriaceae and intra-abdominal surgical site plus urinary-tract infections prevailed in CS-GNB than CR-GNB sepsis. Carbapenemase production was estimated in 76% of CR-GNB isolates. Multivariate logistic regression analysis revealed previous infection (mostly hospital-acquired bacterial infection or sepsis) (OR = 4.28; 95% CI 1.77–10.35), mechanical ventilation (OR = 4.21; 95% CI 1.17–15.18), carbapenem use (OR = 3.42; 95% CI 1.37–8.52) and length of hospital stay (OR = 1.03; 95% CI 1.01–1.05) as independent risk factors for sepsis by CR-GNB. While ICU readmission (OR = 6.92; 95% CI 1.72–27.78) and nosocomial diarrhea (OR = 5.32; 95% CI 1.07–26.45) were factors associated with CS-GNB sepsis.

Conclusions

The investigation of recurrent and not only bacteremic episodes of sepsis was the differential of this study. The results are in agreement with the basic information in the literature. This may help improve management strategies and future studies on sepsis by CR-GNB.

Risk factors for and clinical outcomes of carbapenem non-susceptible gram negative bacilli bacteremia in patients with acute myelogenous leukemia

Background

Carbapenem is frequently used when gram negative bacilli (GNB) bacteremia is detected especially in neutropenic patients. Consequently, appropriate treatment could be delayed in GNB bacteremia cases involving organisms which are not susceptible to carbapenem (carba-NS), resulting in a poor clinical outcomes. Here, we explored risk factors for carba-NS GNB bacteremia and its clinical outcomes in patients with acute myelogenous leukemia (AML) that underwent chemotherapy.

Methods

We reviewed all GNB bacteremia cases that occurred during induction or consolidation chemotherapy, over a 15-year period, in a tertiary-care hospital.

Results

Among 489 GNB bacteremia cases from 324 patients, 45 (9.2%) were carba-NS and 444 (90.8%) were carbapenem susceptible GNB. Independent risk factors for carba-NS GNB bacteremia were: carbapenem use at bacteremia onset (adjusted odds ratio [aOR]: 91.2; 95% confidence interval [95%CI]: 29.3–284.1; P < 0.001); isolation of carbapenem-resistant Acinetobacter baumannii (aOR: 19.4, 95%CI: 3.4–112.5; P = 0.001) in the prior year; and days from chemotherapy to GNB bacteremia (aOR: 1.1 per day, 95%CI: 1.1–1.2; P < 0.001). Carba-NS bacteremia was independently associated with in-hospital mortality (aOR: 6.6, 95%CI: 3.0–14.8; P < 0.001).

Conslusion

Carba-NS organisms should be considered for antibiotic selection in AML patients having these risk factors.

Increased financial burdens and lengths of stay in patients with healthcare-associated infections due to multidrug-resistant bacteria in intensive care units: A propensity-matched case-control study

Background and objectives

Incidence rates of healthcare-associated infections (HAIs) depend upon infection control policy and practices, and the effectiveness of the implementation of antibiotic stewardship. Amongst intensive care unit (ICU) patients with HAIs, a substantial number of pathogens were reported to be multidrug-resistant bacteria (MDRB). However, impacts of ICU HAIs due to MDRB (MDRB-HAIs) remain understudied. Our study aimed to evaluate the negative impacts of MRDB-HAIs versus HAIs due to non-MDRB (non-MRDB-HAIs).

Methods

Among 60,317 adult patients admitted at ICUs of a 2680-bed medical centre in Taiwan between January 2010 and December 2017, 279 pairs of propensity-score matched MRDB-HAI and non-MRDB-HAI were analyzed.

Principal findings

Between the MDRB-HAI group and the non-MDRB-HAI group, significant differences were found in overall hospital costs, costs of medical and nursing services, medication, and rooms/beds, and in ICU length-of-stay (LOS). As compared with the non-MDRB-HAI group, the mean of the overall hospital costs of patients in the MDRB-HAI group was increased by 26%; for categorized expenditures, the mean of costs of medical and nursing services of patients in the MDRB-HAI group was increased by 8%, of medication by 26.9%, of rooms/beds by 10.3%. The mean ICU LOS in the MDRB-HAI group was increased by 13%. Mortality rates in both groups did not significantly differ.

Conclusions

These data clearly demonstrate more negative impacts of MDRB-HAIs in ICUs. The quantified financial burdens will be helpful for hospital/government policymakers in allocating resources to mitigate MDRB-HAIs in ICUs; in case of need for clarification/verification of the medico-economic burdens of MDRB-HAIs in different healthcare systems, this study provides a model to facilitate the evaluations.

Tigecycline Therapy for Infections Caused by Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae in Critically Ill Patients

: We aimed to evaluate tigecycline on the clinical effectiveness in treating complicated skin and soft tissue infections (cSSTI), complicated intra-abdominal infections (cIAI), and pneumonia, caused by extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, as data are limited. From three medical centers in Taiwan, we retrospectively studied the cSSTI, cIAI, and/or pneumonia caused by ESBL-producing Enterobacteriaceae. Among the 71 patients, including 39 patients infected with Klebsiella pneumoniae, 30 infected with Escherichia coli and others, the clinical success rate of tigecycline-based therapy was 80%-90% for pneumonia and cSSTI caused by E. coli and 50%-60% for cIAI caused by K. pneumoniae and E. coli. Microbiological and clinical outcome of pneumonia caused by carbapenem-resistant K. pneumoniae was poor. Univariate Cox analysis showed that dyspnea, SOFA score, septic shock, thrombocytopenia, prolonged prothrombin time, and lesser microbiological eradication were significant factors associated with 30-day mortality after the end of therapy. Cox regression proportional hazards model revealed dyspnea and a SOFA score > 8 to be independently associated with time to death. For ESBL producers, tigecycline showed good effects for cSSTI and pneumonia by E. coli, ordinary for cIAI, but ineffective for pneumonia by K. pneumoniae. Dyspnea and a high SOFA score predict a poor outcome.

Rapid identification of bloodstream bacterial and fungal pathogens and their antibiotic resistance determinants from positively flagged blood cultures using the BioFire FilmArray blood culture identification panel

BACKGROUND/PURPOSE

Rapid and accurate identification of pathogens and their antibiotic resistance directly from flagged blood cultures can aid clinicians in optimizing early antibiotic treatment and improve the clinical outcomes, especially in settings associated with high rates of bloodstream infection caused by vancomycin-resistant Enterococci (VRE) and carbapenem-resistant Enterobacteriaceae (CRE). We compared the results of the BioFire FilmArray Blood Culture Identification (BCID) panel with those of conventional methods for identifying the pathogens and their antibiotic susceptibility status.

METHODS

In total, 100 randomly selected positive blood cultures (BACTEC Plus Aerobic/F bottles or BACTEC Anaerobic Lytic/10 bottles) were analyzed. The pathogen detection efficiency of FilmArray BCID panel was compared with that of conventional method using MALDI-TOF MS system (Bruker MALDI Biotyper) and susceptibility testing by the Vitek 2 system. The sequencing analysis of antibiotic resistance genes was performed for discrepant results obtained from MALDI Biotyper and Vitek 2.

RESULTS

Among the 100 positively flagged blood cultures, 94% of FilmArray BCID panel results were consistent with the MALDI Biotyper results. All five VRE isolates positive for vanA/vanB genes, 10 of 12 Staphylococcus species positive for mecA gene, and only one Klebsiella pneumoniae isolate positive for K. pneumoniae carbapenemase gene (bla_KPC) detected in the FilmArray BCID panel were also concordant with results by the results by conventional susceptibility testing/molecular confirmation.

CONCLUSIONS

The FilmArray BCID panel results not only demonstrated good correlation with conventional blood culture identification and susceptibility results but also provided results rapidly, especially for the early detection of MRSA, VRE and bla_KPC-mediated CRE.

Ignorance of pre-ED healthcare setting is a factor leading to inappropriate initial antibiotic treatment of sepsis in ED and poor outcomes in ICU

OBJECTIVES

Appropriate initial antibiotic therapy is critical for successfully treating sepsis. In the emergency department (ED), clinicians often rely on septic symptoms to guide empirical therapy. The aim of this study was to investigate whether history of contacting pre-ED healthcare setting is easy to be neglected and whether the patients received more inappropriate initial antibiotic therapy and developed poorer outcomes.

METHODS

Septic patients (n = 453) admitted from ED to the intensive care unit (ICU) between 2014 and 2017 were retrospectively selected. Appropriate antibiotic treatment or not was determined by checking whether the selected antibiotics can effectively eradicate the bacteria identified. Various indexes were compared between patients with appropriate and inappropriate initial antibiotic treatments, including septic symptoms (qSOFA scores) in ED, septic-severity change in ICU (SOFA-score ratios), and septic outcomes (APACHE II scores, stay length, 30-day survival probability). These indexes were also compared between pre-ED healthcare and pre-ED community patients.

RESULTS

In comparison with pre-ED community patients, pre-ED healthcare patients received more inappropriate initial antibiotic treatment in ED, showing poorer outcomes in ICU, including septic severity, stay-lengths in ICU and 30-day survival probabilities. Pre-ED settings is more significant than qSOFA scores to predict the inappropriate initial antibiotic treatment.

CONCLUSIONS

Pre-ED healthcare settings, which are indexes for infection with antibiotic resistant pathogens, are easy to be neglected in the first hour in ED. We suggested that standard operating procedure for getting enough information of pre-ED settings should be incorporated to the 1 h bundle of sepsis guideline.

Antimicrobial susceptibilities of the ertapenem-non-susceptible non-carbapenemase-producing Enterobacterales isolates causing intra-abdominal infections in the Asia-Pacific region during 2008-2014: Results from the Study for Monitoring the Antimicrobial Resistance Trends (SMART)

OBJECTIVES

To investigate the susceptibility profiles amongst ertapenem-non-susceptible non-carbapenemase-producing Enterobacterales (ETP-NS-non-CPE) isolates.

METHODS

Minimum inhibitory concentrations (MICs) of 404 ETP-NS-non-CPE isolates collected from different intra-abdominal infection (IAI) sites amongst patients in the Asia-Pacific region during 2008-2014 were determined using the broth microdilution method. The susceptibility results were interpreted according to the MIC breakpoints recommended by the Clinical and Laboratory Standards Institute (CLSI) in 2018. The MICs data of several agents were evaluated based on their published pharmacokinetic/pharmacodynamic (PK/PD) profiles.

RESULTS

The majority (>84%) of IAI-ETP-NS-non-CPE isolates - including Escherichia coli (n=83), Klebsiella pneumoniae (n=91) and Enterobacter species (n=210) - were susceptible to imipenem and amikacin. The 193 hepatobiliary ETP-NS-non-CPE isolates exhibited a trend of lower cefepime MIC (≤4mg/L) distribution than those (n=145) cultured from the peritoneal space (P=0.058). Amongst the ETP-NS-non-CP Enterobacter isolates, 65.7% displayed a cefepime MIC≤4mg/L. In addition, compared with Escherichia coli and Klebsiella pneumoniae isolates, 82.9% and 72.9% of the ETP-NS-non-CP Enterobacter isolates were susceptible to levofloxacin and ciprofloxacin, respectively. Of note, 74.5% and 70.3% of the ETP-NS-non-CP Enterobacter isolates cultured from the hepatobiliary tract and peritoneal space exhibited a ciprofloxacin MIC≤2mg/L and ≤0.25mg/L, respectively. Imipenem and amikacin showed good in vitro susceptibility rates against the IAI-ETP-NS-non-CPE isolates. The hepatobiliary ETP-NS-non-CPE displayed lower cefepime MICs than those cultured from the peritoneal space. Additionally, a significant fraction of IAI-ETP-NS-non-CP Enterobacter isolates exhibited ciprofloxacin MIC ≤ 2mg/L.

CONCLUSION

Based upon the PK/PD analyses, ciprofloxacin, imipenem and cefepime are probably effective against IAI-ETP-NS-non-CPE isolates.

Nanoparticles in the Treatment of Infections Caused by Multidrug-Resistant Organisms

Nanotechnology using nanoscale materials is increasingly being utilized for clinical applications, especially as a new paradigm for infectious diseases. Infections caused by multidrug-resistant organisms (MDROs) are emerging as causes of morbidity and mortality worldwide. Antibiotic options for infections caused by MDROs are often limited. These clinical challenges highlight the critical demand for alternative and effective antimicrobial strategies. Nanoparticles (NPs) can penetrate the cell membrane of pathogenic microorganisms and interfere with important molecular pathways, formulating unique antimicrobial mechanisms. In combination with optimal antibiotics, NPs have demonstrated synergy and may aid in limiting the global crisis of emerging bacterial resistance. In this review, we summarized current research on the broad classification of the NPs that have shown in vitro antimicrobial activity against MDROs, including the ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species). The pharmacokinetics and pharmacodynamic characteristics of NPs and bacteria-resistant mechanisms to NPs were also discussed.

Hypervirulence and carbapenem resistance: two distinct evolutionary directions that led high-risk Klebsiella pneumoniae clones to epidemic success

Introduction: Over the past few decades, Klebsiella pneumoniae has become a significant threat to public health and is now listed as an ESKAPE pathogen. Evolving with versatile capabilities, K. pneumoniae is a population composed of genetically and phenotypically diverse bacteria. However, epidemic K. pneumoniae are restricted to specific clonal lineages. The clonal group CG23 comprises hypervirulent K. pneumoniae displaying limited resistance to antimicrobials and is frequently associated with the community-acquired invasive syndrome. On the other hand, CG258 is another clonal group of K. pneumoniae that has evolved resistance to carbapenems, primarily by acquiring the carbapenemase-encoding genes through nosocomial carriage. Areas covered: With a focus on the high-risk K. pneumoniae clonal lineages CG23 and CG258, we review recent advances including the newly discovered lineage-specific genomic features, and the molecular basis of K. pneumoniae-associated epidemiology, antimicrobial resistance, and hypervirulence. Expert opinion: Both CG23 and CG258 can establish reservoirs in susceptible individuals. Empirical antimicrobial regimens that are prescribed for immediate treatments frequently create selective pressures that favor the high-risk lineages to develop into prominent colonizers. This dilemma reinforces the need for effective therapies that require rapid and accurate diagnosis of epidemic K. pneumoniae.

Randomized Noninferiority Trial of Cefoperazone-Sulbactam versus Cefepime in the Treatment of Hospital-Acquired and Healthcare-Associated Pneumonia

Cefoperazone, a third-generation cephamycin with broad-spectrum antibacterial activity and the ability to permeate bacterial cell membranes, is active against commonly encountered multidrug-resistant pathogens for hospital-acquired pneumonia (HAP) and health care-associated pneumonia (HCAP). To clarify the clinical effects of cefoperazone-sulbactam in the treatment of HAP and HCAP, we conducted an open-label, randomized, noninferiority trial that recruited patients aged ≥18 years suffering HAP/HCAP. Participants were randomly assigned to the cefoperazone-sulbactam (2 g of each per 12 h) or cefepime (2 g per 12 h) arm. Clinical and microbiological responses were evaluated at early posttherapy and test-of-cure visits. Recruited patients were allocated to subpopulations for intent-to-treat (n = 154), per-protocol (n = 147), and safety (n = 166) analyses. Intent-to-treat analysis demonstrated that (i) at the early posttherapy visit, 87.3% of patients receiving cefoperazone-sulbactam and 84.3% of patients receiving cefepime achieved clinical improvement or cure (risk difference of 3.0%; 95% confidence interval [CI], -9.0% to 15.0%), and (ii) at the test-of-cure visit, 73.1% of patients receiving cefoperazone-sulbactam and 56.8% of patients receiving cefepime were assessed as cured (risk difference of 16.3%; 95% CI, 0.0% to 33.0%). These results indicated the noninferiority of cefoperazone-sulbactam to cefepime, which was confirmed by per-protocol analysis. The chest radiographic consolidation/infiltration resolution rate, microbiological eradiation rate, and percentage of adverse events were comparable in both groups. Serious adverse events were rare, and none was judged to be related to the study drugs. Cefoperazone-sulbactam at 2 g every 12 h was noninferior to cefepime at 2 g every 2 h for patients with HCAP.

Impact of an Acinetobacter baumannii outbreak on kidney events in a burn unit: A targeted machine learning analysis

BACKGROUND

Multidrug-resistant (MDR) bacteria outbreaks represent a major threat in intensive care units. Patients may then be exposed to drug-related direct toxicity during such outbreaks. The objective of this study was to explore the impact of an outbreak of imipenem-resistant Acinetobacter baumannii (IR-AB) on renal outcomes.

METHODS

We performed a before-and-after observational study in a French burn intensive care unit during an IR-AB outbreak: a 13-month period before (period A, October 2013-October 2014) and a 13-month period after outbreak control (period B, December 2014-December 2015). A total of 409 patients were included, 195 during period A and 214 during period B. The main endpoint was major adverse kidney events at day 90 (MAKE 90). Secondary endpoints were acute kidney injury (AKI) and persistent renal dysfunction.

RESULTS

Incidence of MAKE 90 was 15.9% during period A versus 11.2% during period B (P = .166) and AKI 28.2% versus 18.7% (P = .023). The use of colistin was associated with renal outcomes in univariate analysis. After adjustment of potential confounding factors using a targeted Machine Learning Analysis (ie, IR-AB-related infection, septic shock, severity scores, other nephrotoxics, chronic kidney disease, serum creatinine at admission, Staphylococcus aureus), colistin remained associated with the risk of MAKE and AKI (relative risk = 2.909, 95% confidence interval [CI] [1.364, 6.204], P = .006 for MAKE 90, and relative risk = 2.14, 95% CI [1.52, 3.02], P<.0001 for AKI).

CONCLUSIONS

The episode of IR-AB outbreak was associated with an increased risk of kidney events, which appears to be driven by the use of colistin.

Antimicrobial activities of ceftazidime-avibactam, ceftolozane-tazobactam, and other agents against Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa isolated from intensive care units in Taiwan: results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan in 2016

Objective

The aim of this study was to investigate the in vitro antimicrobial susceptibilities of clinically important Gram-negative bacteria from seven intensive care units in Taiwan in 2016.

Materials and methods

In total, 300 non-duplicate isolates of Escherichia coli (n=100), Klebsiella pneumoniae (n=100), and Pseudomonas aeruginosa (n=100) collected from 300 patients were studied. The minimum inhibitory concentrations (MICs) of these isolates to antimicrobial agents were determined using the broth microdilution method. Carbapenemase-encoding genes (bla _KPC, bla _NDM, bla _IMP, bla _VIM, and bla _OXA-48-like) were studied for the isolates that were not susceptible to any carbapenems. Sequencing analysis of the mcr genes (mcr-1-5) was conducted for all isolates with colistin MICs ≥4 mg/L.

Results

Ertapenem non-susceptibility was detected in 3% (n=3) E. coli and 12% (n=12) K. pneumoniae isolates. The susceptibility rates of imipenem, ceftazidime-avibactam (CAZ-AVB), and ceftolozane-tazobactam (CLZ-TAZ) were 99%, 99%, and 88%, respectively, for E. coli, 91%, 100%, and 80%, respectively, for K. pneumoniae, and 66%, 91%, and 93%, respectively, for P. aeruginosa. Carbapenemase-encoding genes were not detected in E. coli, were detected in four (33.3%) K. pneumoniae isolates that were not susceptible to ertapenem (three harboring bla _KPC and one harboring bla _OXA-48-like), and were not detected in P. aeruginosa isolates that were not susceptible to imipenem. One K. pneumoniae isolate was resistant to colistin (MIC 4 mg/L) and negative for mcr genes.

Conclusion

CAZ-AVB exhibited excellent activity against carbapenem-resistant Enterobacteriaceae, and CLZ-TAZ exhibited good activity against imipenem-resistant P. aeruginosa.

Infections Caused by Carbapenem-Resistant Enterobacteriaceae: An Update on Therapeutic Options

Carbapenems are considered as last-resort antibiotics for the treatment of infections caused by multidrug-resistant Gram-negative bacteria. With the increasing use of carbapenems in clinical practice, the emergence of carbapenem-resistant pathogens now poses a great threat to human health. Currently, antibiotic options for the treatment of carbapenem-resistant Enterobacteriaceae (CRE) are very limited, with polymyxins, tigecycline, fosfomycin, and aminoglycosides as the mainstays of therapy. The need for new and effective anti-CRE therapies is urgent. Here, we describe the current understanding of issues related to CRE and review combination therapeutic strategies for CRE infections, including high-dose tigecycline, high-dose prolonged-infusion of carbapenem, and double carbapenem therapy. We also review the newly available antibiotics which have potential in the future treatment of CRE infections: ceftazidime/avibactam, which is active against KPC and OXA-48 producers; meropenem/vaborbactam, which is active against KPC producers; plazomicin, which is a next-generation aminoglycoside with in vitro activity against CRE; and eravacycline, which is a tetracycline class antibacterial with in vitro activity against CRE. Although direct evidence for CRE treatment is still lacking and the development of resistance is a concern, these new antibiotics provide additional therapeutic options for CRE infections. Finally, we review other potential anti-CRE antibiotics in development: imipenem/relebactam and cefiderocol. Currently, high-dose and combination strategies that may include the new β-lactam/β-lactamase inhibitors should be considered in severe CRE infections to maximize treatment success. In the future, when more treatment options are available, therapy for CRE infections should be individualized and based on molecular phenotypes of resistance, susceptibility profiles, disease severity, and patient characteristics. More high-quality studies are needed to guide effective treatment for infections caused by CRE.