METHODS: CLSI broth microdilution methodology was used to determine antimicrobial activity and EUCAST breakpoints version 9.0 were used to determine rates of susceptibility and resistance. Isolates were also screened for the genes encoding extended-spectrum β-lactamases (ESBLs) or carbapenemases (including metallo-β-lactamases [MBLs]).

RESULTS: Between 2015 and 2017, this study collected a total of 7051 Enterobacterales isolates and 2032 Pseudomonas aeruginosa isolates from hospitalized patients in Australia, Japan, South Korea, Malaysia, the Philippines, Taiwan, and Thailand. In the Asia-Pacific region, Enterobacterales isolates that were ESBL-positive, carbapenemase-negative (17.9%) were more frequently identified than isolates that were carbapenemase-positive, MBL-negative (0.7%) or carbapenemase-positive, MBL-positive (1.7%). Multidrug-resistant (MDR) isolates of P. aeruginosa were more commonly identified (23.4%) than isolates that were ESBL-positive, carbapenemase-negative (0.4%), or carbapenemase-positive, MBL-negative (0.3%), or carbapenemase-positive, MBL-positive (3.7%). More than 90% of all Enterobacterales isolates, including the ESBL-positive, carbapenemase-negative subset and the carbapenemase-positive, MBL-negative subset, were susceptible to amikacin and ceftazidime-avibactam. Among the carbapenemase-positive, MBL-positive subset of Enterobacterales, susceptibility to the majority of agents was reduced, with the exception of colistin (93.4%). Tigecycline was active against all resistant subsets of the Enterobacterales (MIC90, 1-4 mg/L) and among Escherichia coli isolates, > 90% from each resistant subset were susceptible to tigecycline. More than 99% of all P. aeruginosa isolates, including MDR isolates and the carbapenemase-positive, MBL-positive subset, were susceptible to colistin.

METHODS: A total of 15 PD bags (3 bags for each type of PD solution) containing meropenem and heparin and 24 PD bags (3 bags for each type of PD solution) containing PIP/TZB and heparin were prepared and stored at 4°C for 168 hours. The same bags were stored at 25°C for 3 hours followed by 10 hours at 37°C. An aliquot withdrawn before storage and at defined time points was analyzed for the concentration of meropenem, PIP, TZB, and heparin using high-performance liquid chromatography. Samples were also analysed for particle content, pH and color change, and the anticoagulant activity of heparin.

RESULTS: Meropenem and heparin retained more than 90% of their initial concentration in 4 out of 5 types of PD solutions when stored at 4°C for 168 hours, followed by storage at 25°C for 3 hours and then at 37°C for 10 hours. Piperacillin/tazobactam and heparin were found to be stable in all 8 types of PD solutions when stored under the same conditions. Heparin retained more than 98% of its initial anticoagulant activity throughout the study period. No evidence of particle formation, color change, or pH change was observed at any time under the storage conditions employed in the study.

MATERIALS AND METHODS: Febrile neutropenic patients treated between January 1996 and December 1997 at the pediatric oncology unit of University Hospital, Kuala Lumpur, were prospectively studied. Empirical antibiotic therapy consisted of ceftazidime and amikacin. Those who developed K. pneumoniae bacteremia were identified, and clinical features analyzed. Ceftazidime-resistance was documented via disk-diffusion testing. Production of extended-spectrum beta-lactamase (ESBL) was inferred on the basis of synergy between ceftazidime and amoxicillin-clavulanic acid. The different features between the two groups and variables associated with the development of CRKP bacteremia were analyzed using chi-square and t-tests and calculation of odds ratios. A multivariate analysis was used to identify independent factors for CRKP development.

RESULTS: Ceftazidime-resistance was seen in 51.6% of all K. pneumoniae isolates, and all these isolates were inferred to be ESBL producers. All isolates were sensitive to imipenem. Susceptibility to gentamicin was 90.5%. The mean continuous hospital stay prior to the detection of bacteremia was 13.7 days overall, but significantly longer in the CRKP group (21.9 d) compared to the CSKP group (4.3 d) (P = 0.003). Children with CRKP were more likely to have received antibiotics in the 2 weeks prior to detection of bacteremia (87.5% of cases) than the CSKP group (20.0% of cases) (P = 0.0008). Sepsis-related mortality was higher in those with CRKP (50.0%) than in the CSKP group (13.3%) (P = 0.02). Patients who did not receive CRKP-directed antibiotics within 48 hours of admission were more likely to have a fatal outcome than those who did (P = 0.009). Logistic regression analysis identified use of third-generation cephalosporins 2 weeks prior to presentation and a hospital stay of 2 weeks or more as independent risk factors for development of CRKP.