Carbapenemase-producing organisms (CPO) have been largely responsible for the extensive spread of carbapenem resistance, and their prevalence is increasing in many parts of the world. To evaluate clinical and molecular epidemiology and mortality associated with CPO among patients. All CPO from clinical and long-term healthcare surveillance cultures across Scotland in 2003-2017 were reviewed retrospectively. Polymerase chain reaction was used to detect genes coding for carbapenemases. A generalized linear mixed model was used to identify risk factors for mortality. In total, 290 individuals with CPO were identified. The overall incidence increased over time (P60 years [adjusted odds ratio (aOR) 3.36, 95% confidence interval (CI) 1.06-10.63; P=0.033], presence of non-fermenters (aOR 4.88, 95% CI 1.64-14.47; P=0.005), and systemic infection or organ failure (aOR 4.21, 95% CI 1.38-12.81; P=0.032) were independently associated with 30-day mortality. The incidence of CPO in Scotland is low but increasing. Awareness is required that inpatients aged >60 years, patients with systemic infection or organ failure, and patients presenting with non-fermenters are at higher risk of death from CPO.

Background: Pseudomonas aeruginosa (P. aeruginosa) accounts for high antimicrobial resistance and mortality rates of bloodstream infections (BSIs). We aim to investigate incidence, antimicrobial resistance and risk factors for mortality of P. aeruginosa BSIs among inpatients.Methods: A retrospective cohort study were conducted at two tertiary hospitals in 2017–2021. Medical and laboratory records of all inpatients diagnosed with P. aeruginosa BSIs were reviewed. A generalized linear mixed model was used to identify risk factors for mortality.Results: A total of 285 patients with P. aeruginosa BSIs were identified. Incidence of P. aeruginosa BSIs fluctuated between 2.37 and 3.51 per 100,000 patient-days over the study period. Out of 285 P. aeruginosa isolates, 97 (34.04%) were carbapenem-resistant (CR) and 75 (26.32%) were multidrug-resistant (MDR). These isolates showed low resistance to aminoglycosides (9.51–11.62%), broad-spectrum cephalosporins (17.19–17.61%), fluoroquinolones (17.25–19.43%), and polymyxin B (1.69%). The crude 30-day mortality rate was 17.89% (51/285). Healthcare costs of patients with MDR/CR isolates were significantly higher than those of patients with non-MDR/CR isolates (P < 0.001/=0.002). Inappropriate definitive therapy [adjusted odds ratio (aOR) 4.47, 95% confidence interval (95% CI) 1.35–14.77; P = 0.014], ICU stay (aOR 2.89, 95% CI: 1.26–6.63; P = 0.012) and corticosteroids use (aOR 2.89, 95% CI: 1.31–6.41; P = 0.009) were independently associated with 30-day mortality.Conclusion: Incidence of P. aeruginosa BSIs showed an upward trend during 2017–2020 but dropped in 2021. MDR/CR P. aeruginosa BSIs are associated with higher healthcare costs. Awareness is required that patients with inappropriate definitive antimicrobial therapy, ICU stay and corticosteroids use are at higher risk of death from P. aeruginosa BSIs.

Background: Klebsiella pneumoniae (KP) accounts for high antimicrobial resistance and mortality rates of bloodstream infections (BSIs). Objectives: To investigate incidence, antimicrobial resistance and risk factors for mortality of KP BSIs in East China. Methods: A retrospective study of patients with KP BSIs was conducted in a tertiary care hospital from 2018 to 2022. Medical records of all hospitalised patients with KP BSIs were reviewed and analysed. The incidence, antimicrobial resistance and mortality of KP BSIs were evaluated. The Kaplan-Meier method was used to plot survival curves and logistic regression was used to analyse risk factors for crude 30-day mortality. Results: A total of 379 inpatients with KP BSIs were enrolled. The incidence of patients with KP BSIs was fluctuating between 4.77 and 9.40 per 100,000 patient-days. The crude 30-day mortality rate of these patients was 26.39%. Of the 379 KPisolates, 197 (51.98%) were carbapenem-resistant (CR) and 252 (66.49%) were multidrug-resistant (MDR). All isolates showed the lowest resistance to tigecycline (13.77%) and polymyxin B (14.61%). Cases with MDR/CR isolates had significantly longer length of hospital stay, higher crude 30-day mortality and medical costs than non-MDR/non-CR isolates. Age, CR phenotype, paracentesis, indwelling central venous catheter (CVC), use of carbapenems, tetracyclines, polymyxins B, and irrational empiric treatment were independently associated with crude 30-day mortality. Conclusion: MDR/CR KP BSIs are associated with increased mortality, healthcare costs and prolonged hospitalisation. Patients with advanced age, CR phenotype, paracentesis, CVC, exposure to some antibiotics, and irrational empirical antibiotic treatment are at higher mortality risk.

Bloodstream infections (BSIs) caused by multidrug resistant Pseudomonas aeruginosa (MDRPA) and carbapenem resistant Pseudomonas aeruginosa (CRPA) accounted for high morbidity and mortality. This retrospective cohort study aimed to determine risk factors for MDRPA and CRPA BSIs by examining both clinical and laboratory data of inpatients with MDRPA and CRPA BSIs at two tertiary care hospitals in 2017–2021. Generalized linear mixed models were used to identify risk factors for MDRPA and CRPA BSIs. Factors significantly associated with both MDRPA BSIs and CRPA BSIs included central venous catheter, invasive ventilation including duration of use, urinary catheterization, gastric tube insertion, vancomycin use including quantity of usage, imipenem use including quantity of usage, and tigecycline use. Respiratory infection [adjusted odds ratio (aOR) 2.10, 95% confidence interval (95% CI) 1.00–4.42; P = 0.049] was identified as an independent risk factor for MDRPA BSIs. For CRPA BSIs, independent risk factors included the use of invasive ventilation [aOR 2.82, 95% CI 1.36–5.84; P = 0.005] and a history of tigecycline use [aOR 3.34, 95% CI 1.16–9.58; P = 0.025]. Conversely, circulatory system diseases [aOR 0.41, 95% CI 0.22–0.77; P = 0.006] and quantity of piperacillin-tazobactam use [aOR 0.83, 95% CI 0.72–0.96; P = 0.013] were identified as independent protective factors for CRPA BSIs. Inpatients with respiratory infection, invasive ventilation and a history of tigecycline use are at higher risk of MDRPA and CRPA BSIs. More prudent clinical interventions and antimicrobial therapy should be implemented to inpatients with these factors to prevent and control MDRPA and CRPA BSIs.