Carbapenem-resistant Acinetobacter baumannii (CRAB), an important nosocomial pathogen, occurs particularly in the intensive care unit (ICU). Thus, the aim of this study was to compare the efficacy and safety of documented treatment with colistin monotherapy versus colistin plus meropenem in critically ill patients with CRAB infections at Chiang Mai University Hospital (CMUH). We conducted a retrospective cohort study of critically ill patients with CRAB infections in an ICU from 2015 to 2017, who received colistin monotherapy versus colistin plus meropenem. After propensity score matching, an adjusted odds ratio (aOR) of a 30-day mortality rate in patients who received colistin plus meropenem was 0.43 compared to those who received colistin monotherapy (95% CI, 0.23–0.82, p = 0.01). aORs of clinical response and microbiological response were also higher in patients who received colistin plus meropenem (1.81, 95% CI 1.01–3.26, p = 0.048 and 2.08, 95% CI 1.11–3.91, p = 0.023, respectively). There was no significant difference in nephrotoxicity (aOR, 0.76, 95% CI, 0.43–1.36, p = 0.363) between colistin monotherapy and colistin plus meropenem. In conclusion, the addition of meropenem to colistin caused a reduction in 30-day mortality, higher clinical and microbiological responses, and did not increase nephrotoxicity compared to colistin monotherapy. Furthermore, 30-day mortality was significantly related with age, receiving vasopressor, having malignancy, and the APACHE II score.

Carbapenem-resistant Acinetobacter baumannii (CRAB) is one of the most commonly found nosocomial infections in critically ill patients. However, the appropriate treatment period for a specific group of critically ill patients with CRAB infection is currently being debated. Therefore, our study aimed to evaluate the optimal courses of therapy for critically ill patients with CRAB infection by comparing the outcomes of colistin therapy of short duration (<14 days) versus long duration (≥ 14 days). A retrospective cohort study was conducted at Nakornping Hospital on critically ill patients with CRAB infection who received either a short or long course of colistin treatment between 2015 and 2022. The primary outcome was the 30-day mortality rate while secondary outcomes were clinical response, microbiological response, and nephrotoxicity. Propensity score matching with a 1: 1 ratio was performed to reduce potential biases. Furthermore, a logistic regression model was used to estimate the odds ratio (OR). A total of 374 patients met the inclusion criteria. Two hundred and forty-eight patients were recruited after utilizing propensity scores to match patients at a 1: 1 ratio. The results from the propensity score matching analysis demonstrated that the long-course therapy group had a lower 30-day mortality rate compared to the short-course therapy group (adjusted OR (aOR) = 0.46, 95% CI: 0.26-0.83, p = 0.009). The clinical response and microbiological response rates were higher in patients who received the long course of colistin therapy compared to those receiving the short course (aOR = 3.24, 95% CI: 1.78-5.92, p = 0.001; aOR = 3.01, 95% CI: 1.63-5.57, p = 0.001). There was no significant different in the occurrence of nephrotoxicity (aOR = 1.28, 95% CI: 0.74-2.22, p = 0.368) between the two treatment groups. A long course of colistin therapy resulted in a lower 30-day mortality rate in critically ill patients, and better clinical and microbiological outcomes, but similar nephrotoxicity as compared to a short course of colistin therapy. Therefore, a specific subset of critically ill patients who had CRAB infection needed to be considered for a long course of therapy.

Carbapenem-resistant Acinetobacter baumannii (CRAB) is one of the most common causes of nosocomial infections in critically ill patients. Colistin methanesulfonate (CMS), an inactive prodrug, has been considered as a last-resort treatment for CRAB infection in critically ill patients. The objective of this study was to assess 30-day survival and nephrotoxicity in critically ill patients who received non-loading dose (LD) versus LD of CMS for CRAB infection treatment. Between 2012 and 2017, this retrospective cohort analysis was performed at Chiang Mai University Hospital (CMUH), focusing on critically ill patients with CRAB infection who received either non-LD or LD of CMS. A total of 383 patients met the criteria for inclusion. At the 30th day of treatment, the survival rate of patients in the LD CMS group was 1.70 times (adjusted HR) of those in the non-LD group (95% CI = 1.17–2.50, p = 0.006). Clinical response was significantly higher in the LD CMS group than non-LD CMS group (aHR, 1.35, 95% CI, 1.01–1.82, p = 0.046). In addition, a microbiological response—eradication of pre-treatment isolated pathogens in post-treatment cultures—in patients with LD CMS was 1.57 times that of patients with non-LD CMS (95% CI, 1.15–2.15, p = 0.004). Additionally, there was a significant difference in nephrotoxicity between LD CMS and non-LD CMS (aHR, 1.57, 95% CI, 1.14–2.17, p = 0.006). Based on these results, LD CMS should be used to increase the opportunity of patients to achieve favourable outcomes. However, LD CMS was found associated with an increase in nephrotoxicity, so renal function should be closely monitored when LD colistin was administered.

Carbapenem-resistant Acinetobacter baumannii (CRAB) is becoming more widely recognized as a serious cause of nosocomial infections, and colistin has been reintroduced in recent years for the treatment of CRAB infection. Combinations of colistin and meropenem or imipenem have been found to be effective against CRAB isolates, whereas clinical investigations have not definitively demonstrated the theoretical benefits of colistin combined therapy in patients with CRAB infections. The objective of this study was to compare the primary outcome (30-day survival rate) and secondary outcomes (clinical response, microbiological response and nephrotoxicity) between patients who received loading dose (LD) colistin–meropenem and LD colistin–imipenem for the treatment of CRAB infection. A retrospective cohort analysis was performed at Chiang Mai University Hospital in patients with CRAB infection who received LD colistin–meropenem or LD colistin–imipenem between 2011 and 2017, and 379 patients fulfilled the requirements for the inclusion criteria. The results of this study showed that patients who received LD colistin–imipenem had a lower 30-day survival rate (adjusted HR = 0.57, 95% CI: 0.37–0.90; p = 0.015) and a lower clinical response (aHR = 0.56, 95% CI: 0.35–0.90; p = 0.017) compared with those who received LD colistin–meropenem. The microbiological response in patients with LD colistin–imipenem was 0.52 times (aHR) lower than that in those who received colistin–meropenem (95% CI: 0.34–0.81; p = 0.004); however, there was no significant difference in nephrotoxicity (aHR = 1.03, 95% CI: 0.67–1.57; p = 0.897) between the two combination regimens. In conclusion, when comparing the combination of LD colistin with imipenem or meropenem, the combination of LD colistin and meropenem provides a better survival rate for treating CRAB. Thus, we suggest that combinations of LD colistin and meropenem should be considered when treating CRAB infections.

Acinetobacter baumannii has emerged as a significant concern worldwide. The mortality rate of carbapenem-resistant A. baumannii (CRAB) is increasing, especially in the intensive care unit (ICU). Thus, the objective of this study is to compare the efficacy and safety of colistin plus vancomycin for the treatment of critically ill patients with CRAB in Chiang Mai University Hospital. We conducted a retrospective cohort study of critically ill patients in the ICU with CRAB infection who received colistin alone or colistin-vancomycin combination therapy at Chiang Mai University Hospital. A total of 365 critically ill patients met the inclusion criteria. The results in this study showed that after propensity score matching, colistin plus vancomycin showed no significant differences in the 30-day mortality compared to colistin alone. Likewise, for colistin plus vancomycin, compared with colistin therapy alone, there were no significant differences in the clinical response, microbiological response and nephrotoxicity. In conclusion, colistin plus vancomycin was no significant differences in 30-day mortality, clinical response, microbiological response compared to colistin alone for infections due to CRAB. The nephrotoxicity rates were similar for both groups, so colistin combination with vancomycin was not necessary for the management of infection caused by CRAB.

Vancomycin is a common drug used in children with severe infection. In adults, at least 15 mg/L of the optimal vancomycin trough concentration (Ctrough) is needed to generate the target 24-h area under the concentration-time curve (AUC24) to the minimum inhibitory concentration (MIC) of 400 for a pathogen with the MIC ≤1 mg/L. To determine vancomycin PK in children with severe infection and to explore the correlation between vancomycin Ctrough and AUC24 in children, as well as to propose the appropriate vancomycin dosages using Monte Carlo simulation. Children aged 2-18 years who were admitted to Chiang Mai University Hospital and received intravenous vancomycin for severe infection were included in the study. Serum samples for vancomycin PK were obtained before and serially after the administration of the first dose according to the protocol. Pharmacokinetic analyses were performed using Phoenix WinNonlin® 7.0 and NLME™7.0. Fourteen children with 64% males and age range from 2 to 13 years were included in this study. Non-compartmental analysis revealed the median volume of distribution, clearance, and elimination half-life of 0.58 L/kg, 2.82 mL/kg/min and 2.33 h, respectively. Vancomycin serum concentrations were best described by a two-compartmental model with first-order elimination.The observed Ctrough at 6 h correlated well with the AUC24. The median vancomycin Ctrough at steady state that correlated with the AUC24 ≥ 400 and <800 were 11.18, 9.50, 7.91 and 6.55 mg/L in simulated children receiving vancomycin 40, 60, 80 and 100 mg/kg/day, respectively. Correlation between vancomycin Ctrough and AUC24 values in children has been observed. However, the values of Ctrough that correlate with the target AUC24≥400 in children are lower than the values observed and targeted in adults.