engleski

Klebsiella pneumoniae OXA 48 in an urology patients: Case report

Carbapenems are the drugs of choice for the treatment of infections caused by multiresistant Gram-negative bacilli1. Carbapenemases involved in acquired resistance belong to Ambler class A serin β-lactamases (KPC, SME, GES, IMI, NMC), class B metallo-β-lactamases (MBL) of IMP, VIM or NDM family or OXA-48-like β-lactamases belonging to the class D β-lactamases. The patient was a 68-year-old man, without serious illnesses in his case history, as well as without prior hospitalization in other hospitals. He was hospitalized for the first time in the Department for Urology, University Hospital Center Sisters of Mercy, due to an elevated PSA level. During his first hospitalization, transrectal ultrasound prostate biopsy was performed. After the biopsy the patient experienced no discomfort or dysuria. Histopathological finding revealed prostatic cancer and the patient was admitted for the second time. Radical prostatectomy was performed. The procedure was routine with no complications. One month after surgical treatment the patient was admitted at the Department as an emergent case. His diagnosis upon admission was as follows: urinary retention caused by urinary tract infection. As soon as he was admitted to the same Department, his urine was sampled for microbiological analysis. Urine culture revealed Klebsiella pneumoniae in the quantity of 105. According to the zone diameter breakpoint in disk difusion method, the Klebsiella pneumoniae isolate was resistant to the following antibiotics: ampicillin, amoxicillin-clavulanic acid, piperacillin-tazobactam, cefazolin, cefuroxime iv, ceftibuten, cefixime, ceftriaxone, ceftazidime, cefepime, ertapenem, norfloxacin, levofloxacin, ciprofloxacin, and gentamicin. It was susceptible to amikacin, trimethoprim- sulfamethoxazole and colistin (susceptibility to colistin was determined by using E-test). The strain was intermediate susceptible to imipenem and meropenem. The isolate was positive for ESBLs in inhibitor based test with clavulanic acid (an increase of inhibition zone around cephalosporin disks in the presence of clavulanate for 10 to 15 mm, but negative for AmpC in inhibitor based test with phenylboronic acid. PCR and sequencing revealed blaOXA-48, blaCTX-M-15 and blaSHV-11 with the last one being chromosomally encoded in K. pneumoniae. Laboratory detection of OXA-48 β-lactamase pose a serious problem because of low level carbapenem resistance and sometimes lack of additional ESBL. In our report, the strain did not have elevated carbapenem MICs which complicates laboratory detection. The simoultaneous production of CTX-M- 15 β-lactamase which is responsible for resistance to expanded-spectrum cephalosporins. Microbiological laboratories should be able to detect and characterize carbapenemase producing Enterobacteriaceae in order to prevent the spread of these important „superbags“.

OXA-48, Klebsiella pneumoniae, imipenem, resistance

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