Antimicrobial susceptibility among important pathogens collected as part of the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) in Spain, 2004-2014

Geographical mapping and temporal trends of Acinetobacter baumannii carbapenem resistance: A comprehensive meta-analysis

BACKGROUND

Carbapenem-resistant Acinetobacter baumannii (CRAB) is of critical concern in healthcare settings, leading to limited treatment options. In this study, we conducted a comprehensive meta-analysis to assess the prevalence of CRAB by examining temporal, geographic, and bias-related variations.

METHODS

We systematically searched prominent databases, including Scopus, PubMed, Web of Science, and EMBASE. Quality assessment was performed using the JBI checklist. Subgroup analyses were performed based on the COVID-19 timeframes, years, countries, continents, and bias levels, antimicrobial susceptivity test method and guidelines.

RESULTS

Our comprehensive meta-analysis, which included 795 studies across 80 countries from 1995 to 2023, revealed a surge in carbapenem resistance among A. baumannii, imipenem (76.1%), meropenem (73.5%), doripenem (73.0%), ertapenem (83.7%), and carbapenems (74.3%). Temporally, 2020-2023 witnessed significant peaks, particularly in carbapenems (81.0%) and meropenem (80.7%), as confirmed by meta-regression, indicating a steady upward trend.

CONCLUSION

This meta-analysis revealed an alarmingly high resistance rate to CRAB as a global challenge, emphasizing the urgent need for tailored interventions. Transparency, standardized methodologies, and collaboration are crucial for the accurate assessment and maintenance of carbapenem efficacy.

Overall status of carbapenem resistance among clinical isolates of Acinetobacter baumannii: a systematic review and meta-analysis

BACKGROUND

Resistance to carbapenems, the first-line treatment for infections caused by Acinetobacter baumannii, is increasing throughout the world. The aim of the present study was to determine the global status of resistance to carbapenems in clinical isolates of this pathogen, worldwide.

METHODS

Electronic databases were searched using the appropriate keywords, including: 'Acinetobacter' 'baumannii', 'Acinetobacter baumannii' and 'A. baumannii', 'resistance', 'antibiotic resistance', 'antibiotic susceptibility', 'antimicrobial resistance', 'antimicrobial susceptibility', 'carbapenem', 'carbapenems', 'imipenem', 'meropenem' and 'doripenem'. Finally, following some exclusions, 177 studies from various countries were included in this study. The data were then subjected to a meta-analysis.

RESULTS

The average resistance rate of A. baumannii to imipenem, meropenem and doripenem was 44.7%, 59.4% and 72.7%, respectively. A high level of heterogeneity (I2 > 50%, P value < 0.05) was detected in the studies representing resistance to imipenem, meropenem and doripenem in A. baumannii isolates. Begg's and Egger's tests did not indicate publication bias (P value > 0.05).

CONCLUSIONS

The findings of the current study indicate that the overall resistance to carbapenems in clinical isolates of A. baumannii is relatively high and prevalent throughout the world. Moreover, time trend analysis showed that the resistance has increased from the year 2000 to 2023. This emphasizes the importance of conducting routine antimicrobial susceptibility testing before selecting a course of treatment, as well as monitoring and controlling antibiotic resistance patterns in A. baumannii strains, and seeking novel treatment options to lessen the emergence and spread of resistant strains and to reduce the treatment failure.

Tigecycline-Associated Coagulopathy: A Single-Center Retrospective Analysis

INTRODUCTION

The purpose of this study was to assess clinical characteristics and risk factors for tigecycline-associated prothrombin time (PT) and activated partial thromboplastin time (aPTT) prolongation.

METHODS

We performed a retrospective analysis on coagulation parameters before and during tigecycline treatment in 55 patients in our hospital with severe infections, mainly pneumonia caused by Acinetobacter baumannii. Patients were divided into different groups according to prolongation of PT and aPTT, and clinical features involved were explored. Univariate and multivariable binary logistic regression analyses were used to identify risk factors for tigecycline-associated PT and aPTT increase.

RESULTS

We found that PT values increased from 12.73 ± 1.87 to 13.86 ± 2.06 during the treatment compared with premedication (p < 0.001), and the aPTT level prolonged significantly from 33.63 ± 11.24 to 38.15 ± 11.81 (p < 0.001). The multivariate analyses identified 2 variables that were associated with tigecycline-induced PT prolongation: albumin level (p = 0.018) and weight-adjusted tigecycline dosage (p = 0.005). In addition, treatment duration was the only risk factor for tigecycline-induced aPTT prolongation (p = 0.043).

CONCLUSION

Albumin level, weight-adjusted tigecycline dosage, treatment duration may serve as risk indicators for tigecycline-associated coagulation dysfunction. Physicians should be careful with coagulation disorder when prescribing tigecycline in clinical practice, especially in patients with risk factors.

Cefepime Dosing Requirements in Elderly Patients Attended in the Emergency Rooms

Objective

This study aimed to assess the probability of reaching an adequate pharmacokinetic/pharmacodynamic (pK/pD) index for different cefepime dosages in frail patients with bacteremia treated in the emergency room.

Methods

Simulation study based on Gram-negative bacterial strains that cause bacteremia. The probability of reaching a time above the minimum inhibitory concentration (MIC) at 50% and 100% dosing intervals (fT > 50 and fT > 80% MIC) was assessed for two different renal clearance intervals.

Results

One hundred twenty nine strains were collected, the predominant species being Escherichia coli (n = 83 [64.3%]). In patients with a ClCr of 30 mL/min, an fT > 50% MIC was reached in more than 90% of the simulations. However, a dose of at least 1 g every 12 h must be administered to reach an fT > 80% MIC. In patients with a ClCr of 30–60 mL/min, the probability of reaching an fT > 50% MIC was higher than 90% with doses of 1 g every 8 h or more, but this value was not reached in > 90% simulations for any of the doses tested in this study.

Conclusions

Standard cefepime dosing can reach an adequate PK/PD index in frail patients. Nevertheless, a high dose or extended infusion is necessary to reach an fT > 80% MIC in patients with a ClCr > 60 mL/min.

Epidemiology and risk factors of methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci infections in Zhejiang China from 2015 to 2017

Background

Gram-positive bacteria are dangerous and challenging agents of infection due to their increasing resistance to antibiotics. We aim to analyse the epidemiology and risk factors of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) in Zhejiang China.

Methods

Gram-positive bacteria (including S. aureus, Enterococcus faecalis and Enterococcus faecium) were collected from eighty-six hospitals of eleven cities in Zhejiang China from 2015 to 2017. The detection rates of MRSA and VRE infection were calculated for the non-duplicated isolate according to year, region, hospital level, patient age, specimen type and patient category. Meanwhile, the detected resistances of MRSA, E. faecalis and E. faecium to different antibiotics from 2015 to 2017 were compared. The risk factors and the differences in MRSA and VRE detection rates were compared using odds ratio (OR) with 95% confidence interval (95% CI) and Chi-square test respectively.

Results

From 2015 to 2017, the detection rates of MRSA and VRE decreased gradually. The cities with the highest MRSA and VRE detection rates tended to be adjacent; for example, the neighbouring cities Hangzhou and Quzhou had simultaneously high rates of MRSA and VRE infection. Patients from IIIA hospital who were older than 75 years and in the intensive care unit (ICU) were most at risk. No vancomycin-resistant isolate was found in MRSA. Resistance of E. faecalis and E. faecium to vancomycin and linezolid decreased slightly and then maintained a low level.

Conclusions

The detection rates of MRSA and VRE stayed at moderate and low levels during the three year period of this study, while local dissemination was found in MRSA and VRE isolates. Sustained surveillance is necessary to prevent the spread or clonal dissemination of drug-resistant strains in Zhejiang China.

High incidence of pandrug-resistant Acinetobacter baumannii isolates collected from patients with ventilator-associated pneumonia in Greece, Italy and Spain as part of the MagicBullet clinical trial

OBJECTIVES

To investigate the molecular epidemiology, antimicrobial susceptibility and carbapenem resistance determinants of Acinetobacter baumannii isolates from respiratory tract samples of patients diagnosed with ventilator-associated pneumonia (VAP) who were enrolled in the MagicBullet clinical trial.

METHODS

A. baumannii isolates were prospectively cultured from respiratory tract samples from 65 patients from 15 hospitals in Greece, Italy and Spain. Susceptibility testing was performed by broth microdilution. Carbapenem resistance determinants were identified by PCR and sequencing. Molecular epidemiology was investigated using rep-PCR (DiversiLab) and international clones (IC) were identified using our in-house database.

RESULTS

Of 65 isolates, all but two isolates (97%) were resistant to imipenem and these were always associated with an acquired carbapenemase, OXA-23 (80%), OXA-40 (4.6%), OXA-58 (1.5%) or OXA-23/58 (1.5%). Resistance to colistin was 47.7%. Twenty-two isolates were XDR, and 20 isolates were pandrug-resistant (PDR). The majority of isolates clustered with IC2 (n = 54) with one major subtype comprising isolates from 12 hospitals in the three countries, which included 19 XDR and 16 PDR isolates.

CONCLUSIONS

Carbapenem resistance rates were very high in A. baumannii recovered from patients with VAP. Almost half of the isolates were colistin resistant, and 42 (64.6%) isolates were XDR or PDR. Rep-PCR confirmed IC2 is the predominant clonal lineage in Europe and suggests the presence of an epidemic XDR/PDR A. baumannii clone that has spread in Greece, Italy and Spain. These data highlight the difficulty in empirical treatment of patients with A. baumannii VAP in centres with a high prevalence of carbapenem-resistant A. baumannii.

Clinical Antibiotic-resistant Acinetobacter baumannii Strains with Higher Susceptibility to Environmental Phages than Antibiotic-sensitive Strains

Antibiotic-resistant Acinetobacter baumannii is associated with nosocomial infections worldwide. Here, we used clinically isolated A. baumannii strains as models to demonstrate whether antibiotic resistance is correlated with an increased susceptibility to bacteriophages. In this study, 24 active phages capable of infecting A. baumannii were isolated from various environments, and the susceptibilities of both antibiotic-sensitive and antibiotic-resistant strains of A. baumannii to different phages were compared. In our study, a total of 403 clinically isolated A. baumannii strains were identified. On average, the phage infection percentage of the antibiotic-resistant A. baumannii strains was 84% (from 81–86%), whereas the infection percentage in the antibiotic-sensitive A. baumannii strains was only 56.5% (from 49–64%). In addition, the risk of phage infection for A. baumannii was significantly increased in the strains that were resistant to at least four antibiotics and exhibited a dose-dependent response (p-trend < 0.0001). Among all of the A. baumannii isolates, 75.6% were phage typeable. The results of phage typing might also reveal the antibiotic-resistant profiles of clinical A. baumannii strains. In conclusion, phage susceptibility represents an evolutionary trade-off in A. baumannii strains that show adaptations for antibiotic resistance, particularly in medical environments that have high antibiotic use.

Assessment of the Activity of Tigecycline against Gram-Positive and Gram-Negative Organisms Collected from Italy between 2012 and 2014, as Part of the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.)

As part of the Tigecycline Evaluation and Surveillance Trial (T.E.S.T) we report the in vitro activity of tigecycline and its comparators against Gram-negative and Gram-positive organisms collected from Italian centers between 2012 and 2014. Minimum inhibitory concentrations were determined according to the broth microdilution methodology of the Clinical and Laboratory Standards Institute, and antimicrobial resistance was determined using the European Committee on Antimicrobial Susceptibility Testing interpretive criteria. Among the Enterobacteriaceae, 31% of Escherichia coli isolates, 22% of Klebsiella pneumoniae, and 1% of Klebsiella oxytoca were extended-spectrum β-lactamase producers (ESBLs). Resistance rates among ESBL-K. pneumoniae and ESBL-E. coli to meropenem were 24% and <1%, respectively. Thirty-seven percent of K. pneumoniae were multidrug resistant (MDR) strains. Resistance rates among isolates of Acinetobacter baumannii to amikacin, levofloxacin and meropenem were between 84% and 94%. Eighty percent of A. baumannii isolates were MDR strains. Methicillin-resistant Staphylococcus aureus (MRSA) accounted for 38% of S. aureus isolates. No isolates of MRSA were resistant to linezolid, tigecycline or vancomycin. Antimicrobial resistance remains a problem in Italy with increasing numbers of MDR organisms. Despite high levels, MRSA rates appear to be stabilising. Tigecycline retains its in vitro activity against the majority of organisms, including those with multidrug resistance.