Molecular Characterization of ß-Lactam Resistance and Antimicrobial Susceptibility to Possible Therapeutic Options of AmpC-Producing Multidrug-Resistant Proteus mirabilis in a University Hospital of Split, Croatia.

This study was performed to elucidate genetic relatedness and molecular resistance mechanisms of AmpC-producing multidrug-resistant Proteus mirabilis isolates in University Hospital of Split (UHS), and define efficient antibiotics in vitro. A total of 100 nonrepeated, consecutive, amoxicillin/clavulanate- and cefoxitin-resistant P. mirabilis isolates were collected, mostly from urine (44%) and skin and soft-tissue samples (30%). They were all positive in cefoxitin Hodge test and negative for extended spectrum beta-lactamase production. Pulsed field gel electrophoresis identified four clusters and two singletons, with 79% of isolates in dominant cluster. Molecular characterization and I-CeuI analysis of representatives revealed blaCMY-16 gene located on chromosome, and insertion element ISEcp1 positioned 110 pb upstream of blaCMY-16 starting codon. They also harbored blaTEM-1, except one with blaTEM-2. They were all resistant to trimethoprim-sulfamethoxazole, all but one to quinolones, and 81% to all aminoglycosides, while 77% were susceptible (S) and 22% intermediate (I) to piperacillin/tazobactam, and 4% were S and 68% I to cefepime. Only 15% were S to ceftolozane/tazobactam. Meropenem, ertapenem, ceftazidime/avibactam, temocillin, and fosfomycin were 100% efficient in vitro. This is the first report of blaCMY-16 gene in P. mirabilis from hospital samples in Croatia. The findings are in accordance with Italian and Greek reports. The clonal nature of outbreak suggests the high potential of clonal spread. Alternative agents should be considered to spare carbapenem usage.

Rational Therapy of Urinary Tract Infections in Children in Croatia

Resistance to chemotherapeutics used in the treatment of urinary tract infection is increasing throughout the world. Taking into account clinical experiences, as well as current bacterial resistance in Croatia and neighboring countries, the selection of antibiotic should be the optimal one. Treatment of urinary tract infection in children is particularly demanding due to their age and inclination to severe systemic reaction and renal scarring. If parenteral antibiotics are administered initially, it should be switched to oral medication as soon as possible. Financial aspects of antimicrobial therapy are also very important with the main goal to seek the optimal cost/benefit ratio. Financial orientation must appreciate the basic primum non nocere as a conditio sine qua non postulate as well.