Carbapenem-resistant Acinetobacter baumannii (CRAB) is a critical health concern for the treatment of infectious diseases. The aim of this study was to investigate the molecular epidemiology of CRAB emphasizing the presence of oxacillinase (OXA)-type β-lactamase-encoding genes, one of the most important carbapenem resistance mechanisms. In this study, a total of 183 non-repetitive CRAB isolates collected from 11 tertiary care hospitals across Thailand were investigated. As a result, the blaoxa-51-like gene, an intrinsic enzyme marker, was detected in all clinical isolates. The blaoxa-23-like gene was presented in the majority of isolates (68.31%). In contrast, the prevalence rates of blaoxa-40/24-like and blaoxa-58-like gene occurrences in CRAB isolates were only 4.92% and 1.09%, respectively. All isolates were resistant to carbapenems, with 100% resistance to imipenem, followed by meropenem (98.91%) and doripenem (94.54%). Most isolates showed high resistance rates to ciprofloxacin (97.81%), ceftazidime (96.72%), gentamicin (91.26%), and amikacin (80.87%). Interestingly, colistin was found to be a potential drug of choice due to the high susceptibility of the tested isolates to this antimicrobial (87.98%). Most CRAB isolates in Thailand were of ST2 lineage, but some belonged to ST25, ST98, ST129, ST164, ST215, ST338, and ST745. Further studies to monitor the spread of carbapenem-resistant OXA-type β-lactamase genes from A. baumannii in hospital settings are warranted.

Background: Infectious Diseases Society of America (IDSA) guidelines suggest 7–14 days’ duration of antibiotic treatment for uncomplicated Gram-negative bacteria (GNB) catheter-related bloodstream infection (CRBSI). The objectives of this study were to review microbial epidemiology, to determine rate and risk factors for relapse, and to compare clinical outcomes in patients receiving long- versus short-duration antibiotic therapy. Methods: A retrospective phase 1 study was conducted between January 2010 and October 2016 to review microbial epidemiology and to determine the incidence of and risk factors for relapse in patients with GNB CRBSI, according to the IDSA guidelines diagnostic criteria. In phase 2 of the study, patients without risk factors for relapse between November 2016 and October 2017 were prospectively recruited to receive antibiotic therapy for 7 days after catheter removal. Matched patients from the retrospective phase 1 study who had received antibiotic therapy for ≥14 days were selected as a phase 2 control group to compare outcomes. Results: In phase 1, three most common pathogens identified among 174 cases were Pseudomonas aeruginosa (22.0%), Klebsiella pneumoniae (16.7%), and Stenotrophomonas maltophilia (13.4%). Eighty-nine episodes of infection occurred while patients were receiving antibiotic therapy. Of 140 cases, the relapse rate was 6.4%. Catheter retention was the only risk factor strongly associated with relapse (odds ratio = 145.32; 95% confidence interval 12.66–1667.37, P < 0.001). In phase 2, 11 patients with catheter removal were prospectively recruited to receive short-duration therapy. The number of patients with relapse receiving long- or short-duration therapy was 1 (3%) and 0 (0%), respectively (P = 1.000). Conclusions: For the management of patients with uncomplicated GNB CRBSI, empiric broad-spectrum antibiotic therapy with adequate coverage of P. aeruginosa should be chosen. Catheter removal should be performed to prevent relapse and shortening the duration of treatment could be considered. Trial registration: Thai Clinical Trial Registry: TCTR20190914001. Retrospectively registered on 13 September 2019.

Background: Appropriate antimicrobial dosing is challenging because of changes in pharmacokinetics (PK) parameters and an increase in multidrug-resistant (MDR) organisms in critically ill patients. This study aimed to evaluate the effects of an empirical therapy of high-dose versus standard-dose meropenem in sepsis and septic shock patients. Methods: We performed a prospective randomized open-label study to compare the changes of modified sequential organ failure assessment (mSOFA) score and other clinical outcomes of the high-dose meropenem (2-g infusion over 3 h every 8 h) versus the standard-dose meropenem (1-g infusion over 3 h every 8 h) in sepsis and septic shock patients. Patients’ characteristics, clinical and microbiological outcomes, 14 and 28-day mortality, vasopressor- and ventilator-free days, intensive care unit (ICU) and hospital-free days, percent of the time of antibiotic concentrations above the minimum inhibitory concentration (%T>MIC), and safety were assessed. Results: Seventy-eight patients were enrolled. Median delta mSOFA was comparable between two groups (– 1 in the high-dose group vs. – 1 in the standard-dose group; P value = 0.75). There was no difference between the two groups regarding clinical and microbiological cure, 14- and 28-day mortality, vasopressor- and ventilator-free days, and ICU- and hospital-free days. In patients admitted from the emergency department (ED) with a mSOFA score ≥ 7, the high-dose group demonstrated significantly better microbiological cure compared with the standard-dose group (75% (9/12 patients) vs. 20% (2/10 patients); P value = 0.03). Likewise, the high-dose group presented higher microbiological cure rate in patients admitted from ED who had either APACHE II score > 20 (83.3% (10/12) vs. 28.6% (2/7); P value = 0.045) or on mechanical ventilator (87.5% (7/8) vs. 23.1% (3/13); P value = 0.008) than the standard-dose group. Adverse events were comparable between the two groups. Conclusions: Empirical therapy with the high-dose meropenem presented comparable clinical outcomes to the standard-dose meropenem in sepsis and septic shock patients. Besides, subgroup analysis manifested superior microbiological cure rate in sepsis or septic shock patients admitted from ED. Trial registration: ClinicalTrials.gov, NCT03344627, registered on November 17, 2017

What is Known and Objective Carbapenem‐resistant Enterobacteriaceae (CRE) are virulent gram‐negative bacilli and cause urgent healthcare problems worldwide. One of the main factors leading to the emergence of CRE is antimicrobial consumption. The objective of this study was to assess how closely the rate of antimicrobial consumption and the prevalences of carbapenem‐resistant Escherichia coli (CR‐EC) and carbapenem‐resistant Klebsiella pneumoniae (CR‐KP) are correlated. Methods A retrospective study was performed at a university hospital in Thailand from January 2013 to September 2016. The prevalence of E coli and K pneumoniae was represented as percentages per species per quarter. The antimicrobial consumption rate per quarter was expressed as the defined daily dose (DDD)/1000 patient‐days. Evaluation of the relationships between the rate of antimicrobial consumption and the prevalences of CR‐EC and CR‐KP was conducted via Pearson's or Spearman's correlation analyses. Results and Discussion During the study period, the prevalence of CR‐EC and CR‐KP was less than 6%; however, significantly increasing prevalences were reported for both CR‐EC (r = 0.55, P = 0.03) and CR‐KP (r = 0.87, P < 0.01). There was a significant increasing trend in the consumption of meropenem (r = 0.65, P = 0.01), levofloxacin (r = 0.63, P = 0.01), ceftriaxone (r = 0.55, P = 0.03), ertapenem (r = 0.52, P = 0.05) and the carbapenem group (r = 0.64, P = 0.01). A significant correlation was observed between CR‐KP prevalence and total carbapenem consumption (r = 0.55, P = 0.04). Moreover, levofloxacin consumption had a significant positive relationship with the prevalence of CR‐KP (r = 0.65, P = 0.01). No positive correlation was found with the prevalence of CR‐EC. What is New and Conclusion The rate of consumption of levofloxacin and carbapenems was the important key factor correlated with the rate of emergence of CR‐KP. This is the first report demonstrating the correlation between levofloxacin consumption and CR‐KP prevalence.

This study aimed to identify factors that significantly influence the pharmacokinetics of voriconazole in Thai adults with hematologic diseases, and to determine optimal voriconazole dosing regimens. Blood samples were collected at steady state in 65 patients (237 concentrations) who were taking voriconazole to prevent or treat invasive aspergillosis. The data were analyzed using a nonlinear mixed-effects modeling approach. Monte Carlo simulation was applied to optimize dosage regimens. Data were fitted with the one-compartment model with first-order absorption and elimination. The apparent oral clearance (CL/F) was 3.43 L/h, the apparent volume of distribution (V/F) was 47.6 L, and the absorption rate constant (Ka) was fixed at 1.1 h⁻¹. Albumin and omeprazole ≥ 40 mg/day were found to significantly influence CL/F. The simulation produced the following recommended maintenance doses of voriconazole: 50, 100, and 200 mg every 12 h for albumin levels of 1.5–3, 3.01–4, and 4.01–4.5 g/dL, respectively, in patients who receive omeprazole ≤ 20 mg/day. Patients who receive omeprazole ≥ 40 mg/day and who have serum albumin level 1.5–3 and 3.01–4.5 g/dL should receive voriconazole 50 and 100 mg, every 12 h, respectively. Albumin level and omeprazole dosage should be carefully considered when determining the appropriate dosage of voriconazole in Thai patients.

There are limited intravenous fosfomycin disodium (IVFOS) dosing regimens to treat carbapenem-resistant Enterobacterales (CRE) infections. This study aimed to use Monte Carlo simulation (MCS) for evaluation of IVFOS dosing regimens in critically ill patients with CRE infections. The dosing regimens in critically ill patients with various creatinine clearance were evaluated with MCS using minimum inhibitory concentration (MIC) distributions of fosfomycin against CRE clinical isolates in Thailand and the 24 h area under the plasma drug concentration–time curve over the minimum inhibitory concentration (AUC_0-24/MIC) of ≥21.5 to be a target for IVFOS. The achieved goal of the probability of target attainment (PTA) and a cumulative fraction of response (CFR) were ≥90%. A total of 129 non-duplicated CRE clinical isolates had MIC distributions from 0.38 to >1024 mg/L. IVFOS 8 g every 8 h, 1 h, or 4 h infusion, could achieve approximately 90% PTA of AUC_0-24/MIC target to treat CRE infections with MICs ≤ 128 mg/L. According to PTA target, an IVFOS daily dose to treat carbapenem-resistant Escherichia coli based on Clinical Laboratory Standards Institute (CLSI) breakpoints for urinary tract infections and one to treatment for CRE infections based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints were 16 g/day and 8 g/day, respectively. All dosing regimens of IVFOS against CRE achieved CFR ≤ 70%. This study proposes the IVFOS dosing regimens based on CLSI and EUCAST breakpoints for the treatment of CRE infections. However, further clinical studies are needed to confirm the results of these findings.