Development of Pseudomonas aeruginosa Drug Resistant Due to Prolonged Use of Broad-Spectrum Antibiotics in Severe Viral Infection/Candidemia Cases.

Pre-multidrug-resistant Pseudomonas aeruginosa (Pre-MDRP) defined as resistance to any two of the three antibiotics, such as usually carbapenems, fluoroquinolones and aminoglycosides, is usually induced by inappropriate use of these broad spectrum antibiotics. We experienced two such cases: Case 1 is a 13-years old female patient with recurrent respiratory syncytial virus (RSV) infection. The laboratory data and chest X-ray findings mimicked the bacterial pneumonia, and tazobactam/piperacillin (TAZ/PIPC), levofloxacin (LVFX), and meropenem (MEPM). However, her condition did not improve, and pre-MDRP was isolated and treated by ciprofloxacin (CPFX). Case 2 is 66 years old male with the history with P. aeruginosa was previously isolated and LVFX was used because bacterial pneumonia was suspected. However, Candida albicans from blood followed by pre-MDRP was isolated from sputum, and he was treated by micafungin and CPFX. The cases suggested that prolonged and/or repeated exposure to anti-pseudomonas agents without appropriate microbial diagnosis and de-escalation of antibiotics might be induce the resistant pathogens and the relevance of pre-MDRP might be an early warning stage in antimicrobial resistance.