PYOGENIC LIVER ABSCESS – ETIOLOGICAL SPECTRUM AND SENSITIVITY TO ANTIBIOTICS

Abstract

Introduction: Pyogenic liver abscess (PLA) is a serious challenge in modern medical practice. The aim of this study was to investigate the etiology and antimicrobial susceptibility of PLA-associated microbial pathogens, diagnosed in hospitalized patients at St. Marina University Hospital of Varna during the period between 2001 and 2016. Materials and Methods: A total of 84 clinical samples (pus aspirates, n=72, bile samples, n=7, and blood cultures, n=5), collected from PLA patients, hospitalized in the Second Surgery Clinic were analyzed. Species identification was performed by conventional methods. Antimicrobial susceptibility was studied by disk diffusion method and Phoenix 100 (BD). The results were interpreted according to CLSI and EUCAST standards. Results: Causative bacterial agents belonging to 15 different species were isolated in 59 cases (in 70%). E. coli (23.7%) , K. pneumoniae (20%) , E. cloacae (13.5%) , E. faecalis (8.5%) , P. mirabilis (5%) and P. aeruginosa (5%) dominated in the etiological spectrum. E. coli demonstrated the following levels of antimicrobial susceptibility: imipenem, amikacin, piperacillin/tazobactam, 100%; ceftazidime, cefepime, 90.9%; cefuroxime, 83.3%; amoxicillin/clavulanic acid, 77.8%; gentamicin, 75%; levofloxacin, cefalothin, 66.6%; ciprofloxacin, 63.6%; piperacillin, 58.3%; ampicillin, 45.5%. The following antimicrobial susceptibility rates were determined for K. pneumoniae : imipenem, 100%; amikacin, 92.3%; ceftazidime, cefepime, 80%; cefalothin, cefuroxime, 75%; levofloxacin, gentamicin, 66.6%; ciprofloxacin, 62.5%; piperacillin/tazobactam, 57.1%; piperacillin, 25% and amoxicillin/clavulanic acid, 22.2%. Conclusions: E. coli and K. pneumonia are the predominant pathogens in PLA patients. Carbapenems are the most active antimicrobial agents followed by ceftazidime and cefepime. In the aminoglycoside group, amikacin demonstrates the best in vitro activity.