Do specific antimicrobial stewardship interventions have an impact on carbapenem resistance in Gram-negative bacilli? A multicentre quasi-experimental ecological study: time-trend analysis and characterization of carbapenemases

Impact of an antimicrobial stewardship programme on antibiotic utilization and resistance burden in patients with acute leukaemia: an 11-year longitudinal cohort study using interrupted time-series analysis

BACKGROUND

Antimicrobial resistance (AMR), driven by inappropriate and overuse of antibiotics, poses a significant threat, especially to patients with acute leukaemia.

OBJECTIVES

To evaluate the impact of antimicrobial stewardship programmes (ASPs) on antibiotic use and analyse temporal changes in bloodstream infections (BSI) caused by AMR organisms.

METHODS

We performed a retrospective, interventional, longitudinal cohort study spanning an 11-year period. ASPs included optimizing antibiotic use, enhancing tracking and reporting systems and delineating leadership and accountability. A segmented regression model of interrupted time series was used to evaluate the trend of antibiotic consumption and BSI with AMR organisms after the interventions.

RESULTS

A total of 3296 BSI episodes with 454 419 days of therapy (DOT) from 7754 patients were obtained. ASPs were significantly associated with an immediate reduction [-70.03 DOT/1000 patient-days (PD), P = 0.036] and a decreasing trend (-11.65 DOT/1000 PD per quarter, P < 0.001) in overall antibiotic use. The increasing incidence of BSI with AMR before ASP intervention was notably curbed and revealed a decreasing trend (slope change: -0.06 BSI/1000 PD per quarter, P = 0.002). The decreasing trend was more significant for Enterobacterales: ciprofloxacin-resistant and ESBL-producing isolates showed a slope change of -0.06 BSI/1000 PD and -0.08 BSI/1000 PD per quarter, respectively (all P < 0.05). However, Pseudomonas aeruginosa BSI increased.

CONCLUSIONS

Multidimensional ASPs effectively reduced both the immediate and trends in overall antibiotic usage even in patients with acute leukaemia. Additionally, there was a notable decrease in the incidence of BSI caused by AMR organisms, particularly among Enterobacterales.

Evaluation of three commercial methods of susceptibility testing for ceftolozane/tazobactam against carbapenem-resistant Pseudomonas aeruginosa

INTRODUCTION

Ceftolozane/tazobactam has shown excellent activity against Pseudomonas aeruginosa, but this drug is not always included in commercial panels. The aim of the study was to evaluate the performance of 2 gradient strips (BioMérieux and Liofilchem) and a commercial microdilution panel (Sensititre, EURGNCOL panel) using this combination against carbapenem-resistant P. aeruginosa isolates.

METHODS

Three commercial methods were tested with 41 metallo-beta-lactamase-producing and 59 non-carbapenemase-producing P. aeruginosa isolates. Broth microdilution was used as reference.

RESULTS

All carbapenemase-producing isolates and only one non-producing isolate were resistant to this antibiotic. Both essential agreement and bias were outside the acceptance intervals since MIC values were higher than reference values for all three methods. The Kappa index indicated poor or weak agreement. Changes in clinical categories were observed in 3 isolates.

CONCLUSIONS

The three methods yielded poor agreement with the reference. Despite the differences in MIC values, fewer than 3% involved category changes.

Modelling antimicrobial resistance transmission to guide personalized antimicrobial stewardship interventions and infection control policies in healthcare setting: a pilot study

Infection control programs and antimicrobial stewardship have been proven effective in reducing the burden of diseases due to multidrug-resistant organisms, but quantifying the effect of each intervention is an open issue. For this aim, we propose a model to characterize the effect of interventions at single ward level. We adapted the Ross-Macdonald model to describe hospital cross-transmission dynamics of carbapenem resistant Klebsiella pneumoniae (CRKP), considering healthcare workers as the vectors transmitting susceptible and resistant pathogens among admitted patients. The model parameters were estimated from a literature review, further adjusted to reproduce observed clinical outcomes, and validated using real life data from a 2-year study in a university hospital. The model has been further explored through extensive sensitivity analysis, in order to assess the relevance of single interventions as well as their synergistic effects. Our model has been shown to be an effective tool to describe and predict the impact of interventions in reducing the prevalence of CRKP colonisation and infection, and can be extended to other specific hospital and pathological scenarios to produce tailored estimates of the most effective strategies.

Comparison of Cefepime with Piperacillin/Tazobactam Treatment in Patients with Hospital-Acquired Pneumonia

Although cefepime and piperacillin/tazobactam are commonly prescribed for the treatment of hospital-acquired pneumonia (HAP), which one is the superior therapy remains unclear. Using Korean National Health Insurance Service data from January 2018 to December 2018, we compared the clinical outcomes of patients with HAP who were treated with cefepime and those treated with piperacillin/tazobactam. Data from 9955 adult patients with HAP, of whom 1502 (15%) received cefepime and 8453 (85%) received piperacillin/tazobactam, were retrieved for primary analysis. Tube feeding, suctioning, positioning care, and intensive care unit admission were more common among patients who received piperacillin/tazobactam. Treatment outcomes, including rates of in-hospital mortality, pneumonia-related readmission, and all-cause mortality within 6 months after discharge, were comparable between the two groups. In a subgroup analysis of data from patients who required tube feeding, the risk for in-hospital mortality was significantly higher among those who received cefepime (fully adjusted odds ratio, 1.43; 95% confidence interval, 1.04-1.97; p = 0.042). Treatment outcomes did not differ between patients who received cefepime and those who received piperacillin/tazobactam treatment, but among patients who were at risk for aspiration, such as those receiving tube feeding, those who received piperacillin/tazobactam had lower rates of in-hospital mortality.

Updates on the Status of Carbapenem-Resistant Enterobacterales in Lebanon

Carbapenem-resistant Enterobacterales (CRE) pathogens have been increasingly isolated and reported in Lebanon. Several studies have been published over the last two decades about the CRE situation in the country. However, compared to the worldwide data, those studies are scarce and mostly restricted to single center studies. In this review, we aim to present a comprehensive and reliable report illustrating the current situation regarding CRE in Lebanon. Variable studies have shown an increasing pattern of carbapenem resistance in Enterobacterales since the first reports of CRE isolates in 2007 and 2008. Escherichia coli and Klebsiella pneumoniae were the most detected ones. The OXA-48 class D carbapenemases were the most prevalent carbapenemases among CRE isolates. Moreover, the emergence of other carbapenemases like the NDM class B carbapenemase has been noticed. Strict infection control measures in hospitals, including the identification of CRE carriers, are needed in Lebanese hospitals since carriage is a potential risk for the spread of CRE in healthcare settings. The dissemination of CRE in the community is noticed and attributed to multiple causes, such as the refugee crisis, water contamination, and antimicrobial misuse. In conclusion, strict infection control measures in healthcare settings, in addition to accurate antimicrobial stewardship program implementation, are urgently needed.

Antimicrobial stewardship programs in the Intensive Care Unit in patients with infections caused by multidrug-resistant Gram-negative bacilli

Antimicrobial stewardship programs (ASPs) have been shown to be effective and safe, contributing to reducing and adjusting antimicrobial use in clinical practice. Such programs not only reduce antibiotic selection pressure and therefore the selection of multidrug-resistant strains, but also reduce the potential deleterious effects for individual patients and even improve the prognosis by adjusting the choice of drug and dosage, and lessening the risk of adverse effects and interactions. Gram-negative bacilli (GNB), particularly multidrug-resistant strains (MDR-GNB), represent the main infectious problem in the Intensive Care Unit (ICU), and are therefore a target for ASPs. The present review provides an update on the relationship between ASPs and MDR-GNB.

Geographic patterns of Acinetobacter baumannii and carbapenem resistance in the Asia-Pacific Region: results from the Antimicrobial Testing Leadership and Surveillance (ATLAS) program, 2012-2019

OBJECTIVES

This study aimed to investigate the geographic distribution of carbapenem-resistant Acinetobacter baumannii (CR-AB) isolates in the Asia-Pacific region.

METHODS

We collected A. baumannii isolates using the Antimicrobial Testing Leadership and Surveillance program from 2012 to 2019. The minimum inhibitory concentrations (MICs) of the isolates were determined using the broth microdilution method. The major carbapenemase genes were identified using multiplex polymerase chain reaction assays for the isolates collected between 2012 and 2014. CR-AB was defined as isolates with meropenem MICs ≥8 mg/l.

RESULTS

In total, 2674 A. baumannii isolates were collected from 13 countries, of which 1918 (71.7%) were CR-AB. The carbapenem resistance rates among A. baumannii isolates were as low as 2.8% and 6.5% in Japan and Australia, respectively, but as high as 88% and 87.2% in South Korea and India, respectively. Of the 232 CR-AB isolates that underwent carbapenemase gene screening, 224 (96.6%) harbored at least one carbapenemase gene. A total of 226 carbapenemase genes were detected, with bla_OXA-23 (94.7%, 214/226) being the most dominant, followed by bla_OXA-72 (2.7%, 6/226), bla_OXA-58 (2.2%, 5/226), and bla_NDM-1 (0.4%, 1/226). CR-AB isolates had >80% resistance to amikacin, ampicillin/sulbactam, cefepime, ceftazidime, ciprofloxacin, levofloxacin, and piperacillin/tazobactam. The rates of CR-AB resistance to minocycline and colistin were 7.2% (31/429) and 1.7% (23/1368). For cefoperazone/sulbactam and tigecycline, 50.2% (527/1049) and 93.3% (1789/1918) of CR-AB isolates had an MIC ≤16 mg/l and ≤2 mg/l, respectively.

CONCLUSION

The prevalence of carbapenem resistance in A. baumannii showed significant differences among countries in the Asia-Pacific region, and the treatment options were limited.

The Effect of Decreased Antipseudomonal Drug Consumption on Pseudomonas aeruginosa Incidence and Antimicrobial Susceptibility Profiles over 9 Years in a Lebanese Tertiary Care Center

Pseudomonas aeruginosa (PAE) is intrinsically resistant to numerous classes of antimicrobials such as tetracycline and β-lactam antibiotics. More epidemiological surveillance studies on the antimicrobial susceptibility profiles of PAE are needed to generate clinically significant data and better guided therapeutic options. We describe and analyze in a retrospective study the epidemiologic trends of 1827 Pseudomonas spp. isolates (83.5% PAE, 16.4% Pseudomonas sp., and 0.2% Pseudomonas putida) from various clinical specimens with their resistance patterns to antimicrobial consumption at a tertiary medical center in Lebanon between January 2010 and December 2018. We report a significant drop in the incidence of PAE from sputum (p-value = 0.05), whereas bloodstream infection isolation density showed no trend over the study period. We also registered a minimal but statistically significant drop in resistance of Pseudomonas to certain antibiotics and a decrease in the consumption of antipseudomonal antibiotics (p-value < 0.001). Only 61 PAE isolates from a total of 1827 Pseudomonas cultures (3.33%) were difficult to treat, of which only one was a bacteremia. Interestingly, we found that the carbapenem susceptibility of Pseudomonas was unaffected by the decrease in their consumption. These results augur that antimicrobial pressure may not be the sole contributor to resistance emergence. Finally, antimicrobial stewardship seems to have a positive impact on nosocomial epidemiology.

The Impact of Antimicrobial Stewardship and Infection Control Interventions on Acinetobacter baumannii Resistance Rates in the ICU of a Tertiary Care Center in Lebanon

Antimicrobial resistance is a serious threat to global health, causing increased mortality and morbidity especially among critically ill patients. This toll is expected to rise following the COVID-19 pandemic. Carbapenem-resistant Acinetobacter baumannii (CRAb) is among the Gram-negative pathogens leading antimicrobial resistance globally; it is listed as a critical priority pathogen by the WHO and is implicated in hospital-acquired infections and outbreaks, particularly in critically ill patients. Recent reports from Lebanon describe increasing rates of infection with CRAb, hence the need to develop concerted interventions to control its spread. We set to describe the impact of combining antimicrobial stewardship and infection control measures on resistance rates and colonization pressure of CRAb in the intensive care units of a tertiary care center in Lebanon before the COVID-19 pandemic. The antimicrobial stewardship program introduced a carbapenem-sparing initiative in April 2019. During the same period, infection control interventions involved focused screening, monitoring, and tracking of CRAb, as well as compliance with specific measures. From January 2018 to January 2020, we report a statistically significant decrease in carbapenem consumption and a decrease in resistance rates of isolated A. baumannii. The colonization pressure of CRAb also decreased significantly, reaching record low levels at the end of the intervention period. The results indicate that a multidisciplinary approach and combined interventions between the stewardship and infection control teams can lead to a sustained reduction in resistance rates and CRAb spread in ICUs.

Acquisition of carbapenem-resistant gram-negative bacilli among intensive care unit (ICU) patients with no previous use of carbapenems: Indirect population impact of antimicrobial use

Objective:

To measure the impact of exposure to patients using carbapenem on the acquisition of carbapenem-resistant gram-negative bacilli (CR-GNB) among patients not using carbapenems.

Design:

An ecological study and a cohort study.

Setting:

Two medical surgical intensive care units (ICUs) in inner Brazil.

Participants:

Patients admitted to 2 ICUs from 2013 through 2018 to whom carbapenem was not prescribed.

Methods:

In the ecologic study, the monthly use of carbapenems (days of therapy [DOT] per 1,000 patient days) was tested for linear correlation with the 2-month moving average of incidence CR-GNB among patients to whom carbapenem was not prescribed. In the cohort study, those patients were addressed individually for risk factors (demographics, invasive interventions, use of antimicrobials) for acquisition of CR-GNB, including time at risk and the “carbapenem pressure,” described as the aggregate DOT among other ICU patients during time at risk. The analysis was performed in univariate and multivariable Poisson regression models.

Results:

The linear regression model revealed an association of total carbapenem use and incidence of CR-GNB (coefficient, 0.04; 95% confidence interval [CI], 0.02–0.06; P = .001). In the cohort model, the adjusted rate ratio (RR) for carbapenem DOT was 1.009 (95% CI, 1.001–1.018; P = .03). Other significant risk factors were mechanical ventilation and the previous use of ceftazidime (with or without avibactam).

Conclusions:

Every additional DOT of total carbapenem use increased the risk of CR-GNB acquisition by patients not using carbapenems by nearly 1%. We found evidence for a population (“herd effect”-like) impact of antimicrobial use in the ICUs.

Epidemiology and infection control of carbapenem resistant Acinetobacter baumannii and Klebsiella pneumoniae at a German university hospital: a retrospective study of 5 years (2015-2019)

Background

Carbapenem resistant (CR) Klebsiella pneumoniae (Kp) and Acinetobacter baumannii (Ab) are emerging multidrug resistant bacteria with very limited treatment options in case of infection. Both are well-known causes of nosocomial infections and outbreaks in healthcare facilities.

Methods

A retrospective study was conducted to investigate the epidemiology of inpatients with CR Kp and CR Ab in a 1500-bed German university hospital from 2015 to 2019. We present our infection control concept including a weekly microbiologic screening for patients who shared the ward with a CR Kp or CR Ab index patient.

Results

Within 5 years, 141 CR Kp and 60 CR Ab cases were hospitalized corresponding to 118 unique patients (74 patients with CR Kp, 39 patients with CR Ab and 5 patients with both CR Ab and CR Kp). The mean incidence was 0.045 (CR Kp) and 0.019 (CR Ab) per 100 inpatient cases, respectively. Nosocomial acquisition occurred in 53 cases (37.6%) of the CR Kp group and in 12 cases (20.0%) of the CR Ab group. Clinical infection occurred in 24 cases (17.0%) of the CR Kp group and in 21 cases (35.0%) of the CR Ab group. 14 cases (9.9%) of the CR Kp group and 29 cases (48.3%) of the CR Ab group had a history of a hospital stay abroad within 12 months prior to admission to our hospital. The weekly microbiologic screening revealed 4 CR Kp cases caused by nosocomial transmission that would have been missed without repetitive screening.

Conclusions

CR Kp and CR Ab cases occurred infrequently. A history of a hospital stay abroad, particularly in the CR Ab group, warrants pre-emptive infection control measures. The weekly microbiologic screening needs further evaluation in terms of its efficiency.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06900-3.

Combined Resistance to Ceftolozane-Tazobactam and Ceftazidime-Avibactam in Extensively Drug-Resistant (XDR) and Multidrug-Resistant (MDR) Pseudomonas aeruginosa: Resistance Predictors and Impact on Clinical Outcomes Besides Implications for Antimicrobial Stewardship Programs

A retrospective case-control study was conducted at Modena University Hospital from December 2017 to January 2019 to identify risk factors and predictors of MDR/XDR Pseudomonas aeruginosa (PA) isolation with resistance to ceftazidime/avibactam (CZA) and ceftolozane/tazobactam (C/T), and of mortality among patients infected/colonized. Among 111 PA isolates from clinical/surveillance samples, 60 (54.1%) were susceptible to both drugs (S-CZA-C/T), while 27 (24.3%) were resistant to both (R-CZA-C/T). Compared to patients colonized/infected with S-CZA-C/T, those with R-C/T + CZA PA had a statistically significantly higher Charlson comorbidity score, greater rate of previous PA colonization, longer time before PA isolation, more frequent presence of CVC, higher exposure to C/T and cephalosporins, longer hospital stay, and higher overall and attributable mortality. In the multivariable analysis, age, prior PA colonization, longer time from admission to PA isolation, diagnosis of urinary tract infection, and exposure to carbapenems were associated with the isolation of a R-C/T + CZA PA strain, while PA-related BSI, a comorbidity score > 7, and ICU stay were significantly associated with attributable mortality. C/T and CZA are important therapeutic resources for hard-to-treat PA-related infections, thus specific antimicrobial stewardship interventions should be prompted in order to avoid the development of this combined resistance, which would jeopardize the chance to treat these infections.

Strategies to Improve Antimicrobial Utilization with a Special Focus on Developing Countries

Antimicrobial resistance (AMR) is a high priority across countries as it increases morbidity, mortality and costs. Concerns with AMR have resulted in multiple initiatives internationally, nationally and regionally to enhance appropriate antibiotic utilization across sectors to reduce AMR, with the overuse of antibiotics exacerbated by the COVID-19 pandemic. Effectively tackling AMR is crucial for all countries. Principally a narrative review of ongoing activities across sectors was undertaken to improve antimicrobial use and address issues with vaccines including COVID-19. Point prevalence surveys have been successful in hospitals to identify areas for quality improvement programs, principally centering on antimicrobial stewardship programs. These include reducing prolonged antibiotic use to prevent surgical site infections. Multiple activities centering on education have been successful in reducing inappropriate prescribing and dispensing of antimicrobials in ambulatory care for essentially viral infections such as acute respiratory infections. It is imperative to develop new quality indicators for ambulatory care given current concerns, and instigate programs with clear public health messaging to reduce misinformation, essential for pandemics. Regular access to effective treatments is needed to reduce resistance to treatments for HIV, malaria and tuberculosis. Key stakeholder groups can instigate multiple initiatives to reduce AMR. These need to be followed up.