Antimicrobial Susceptibility Trends and Risk Factors for Antimicrobial Resistance inPseudomonas aeruginosaBacteremia: 12-Year Experience in a Tertiary Hospital in Korea

Abstract

Background Infections caused by multidrug-resistant Pseudomonas aeruginosa (MDRPA) have been on the rise worldwide, and delayed active antimicrobial therapy is associated with high mortality. However, few studies have evaluated increases in P. aeruginosa infections with antimicrobial resistance and risk factors for such antimicrobial resistance in Korea. Here, we analyzed changes in antimicrobial susceptibility associated with P. aeruginosa bacteremia and identified risk factors of antimicrobial resistance. Methods The medical records of patients with P. aeruginosa bacteremia who were admitted to a tertiary hospital between January 2009 and October 2020 were retrospectively reviewed. Antibiotic resistance rates were compared among the time periods of 2009–2012, 2013–2016, and 2017–2020 and between the intensive care unit (ICU) and non-ICU setting. Empirical antimicrobial therapy was considered concordant, if the organism was susceptible to antibiotics in vitro, and discordant, if resistant. Results During the study period, 295 patients with P. aeruginosa bacteremia were identified. The hepatobiliary tract (26.8%) was the most common primary site of infection. The rates of carbapenem-resistant P. aeruginosa (CRPA), MDRPA, and extensively drug-resistant P. aeruginosa (XDRPA) were 24.7%, 35.9%, and 15.9%, respectively. XDRPA showed an increasing trend, and CRPA, MDRPA, and XDRPA were also gradually increasing in non-ICU setting. Previous exposure to fluoroquinolones and glycopeptides and urinary tract infection were independent risk factors associated with CRPA, MDRPA, and XDRPA. Previous exposure to carbapenems was an independent risk factor of CRPA. CRPA, MDRPA, and XDRPA were associated with discordant empirical antimicrobial therapy. Conclusion The identification of risk factors for antimicrobial resistance and analysis of antimicrobial susceptibility might be important for concordant empirical antimicrobial therapy in patients with P. aeruginosa bacteremia.

Carbapenem Resistant Pseudomonas aeruginosa Infections in Elderly Patients: Antimicrobial Resistance Profiles, Risk Factors and Impact on Clinical Outcomes

“…Another one attributed to CRPA infection was indwelling devices in the patient’s body, similar to previous studies by Leihof RF 30 and Kang JS, 13 patients undergone foley catheter had approximately twice as high rate of CRPA infection occurrence as those without foley catheter. Indwelling catheter is easy to destroy patients with urethral or bladder mucosa, the mucosal barrier, during invasive operation and weaken its defensive effect, increasing the chance of bacterial invasion and resulting in increased chance of infection with P. aeruginosa .…”

“…An important predisposing factor for CRPA infection having the history of using carbapenems and third- or fourth-generation cephalosporins within 30 days increased the risk about seven and thirteen times higher, which concurs with other previous studies. 13 , 20 – 21 Resistance acquisition driven by antipseudomonal agents exposure can be reached by either selecting mutants in patients previously colonized or infected by susceptible phenotypes or promoting selection of an already resistant strain. 22 – 23 Long-term and high frequency usage of such antibiotics causes P. aeruginosa to undergo gene mutation or produce new drug resistance genes for survival under the pressure of antibiotics, resulting in changes in the drug resistance characteristics of bacteria.…”

“…Furthermore, cerebrovascular disease was significantly linked to CRPA infection. 13 The elderly with cerebrovascular disease are often subjected to repeated silent aspiration pneumonia, bacteria colonized in the oral cavity and oropharynx easily enter the lung during sleep causing an infection. A previous study revealed high prevalence (38.5%) and high average bacterial number (2.00×10 8 CFU/mL) of P. aeruginosa were found in oropharyngeal microflora with cerebrovascular disease and dysphagia.…”

“…Indwelling catheter is easy to destroy patients with urethral or bladder mucosa, the mucosal barrier, during invasive operation and weaken its defensive effect, increasing the chance of bacterial invasion and resulting in increased chance of infection with P. aeruginosa . 13 , 31 Therefore, it is vital to emphasize the importance of avoiding or limiting the use of this type of invasive device and improving the aseptic conditions during these procedures, especially in elderly patients.…”

“… 10 However, previous studies mainly focused on particular populations, such as patients with hematologic malignancies, 11 kidney transplant recipients, 12 bacteremia. 13 So far, the prevalence, risk factors and clinical impact on mortality of CRPA infection are unclear in elderly patients. Here, we aimed to clarify the prevalence, the clinical manifestations, antimicrobial resistance, risk factors and outcomes of elderly inpatients with CRPA infection.…”