Tehran University Medical Journal

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We report our experience with 124 patients were referred 70 our urology clinic in Sina hospital for urinary retention. Serum PSA analyzed by using a monoclonal assay. All patients underwent digital rectal examination. The patients devided in 3 groups: Group 1 (87 men) with a serum PSA level less than 4 ng/ml, group 2 (26 men) with a serum PSA level 4-10 ng/ml and group 3 (11 men) with a serum PSA level greater than 10 ng/ml. After prostate biopsy and trans urethral resection or open prostatectomy, of the 87 men in group 1, one man had cancer of the prostate, of the 26 men in group 2, 2 men had cancer of the prostate and of the 11 men in group 3, 9 men had prostate cancer.

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Background: The resistance of Pseudomonas aeruginosa strains to broad spectrum cephalosporins may be mediated by extended spectrum b-lactamases (ESBLs). These enzymes are encoded by different genes located either on chromosome or plasmids. In this study, we determined the antimicrobial resistance patterns of P. aeruginosa isolates and screened for ESBL production.

Methods: After isolation from burn patients in Tehran Hospital, identification of P. aeruginosa isolates were assessed using biochemical tests. We then performed disk agar diffusion (DAD) according to CLSI guidelines to determine the pattern of antimicrobial resistance. The frequency of ESBLs and prevalence of the OXA-10 and PER-1 genes were determined with combined disk and polymerase chain reaction (PCR) methods, respectively.

Results: One hundred strains of P. aeruginosa were isolated. The resistance of these strains to cephpodoxime, aztreonam, ciprofloxacin, ofloxacin, ceftazidime, cefepime, imipenem, meropenem, cefotaxime, levofloxacin, piperacilin- tazobactam and ceftriaxon was 100%, 90%, 83%, 92%, 85%, 88%, 63%, 66%, 98%, 89%, 70% and 91%, respectively. Of these, 40 strains (40%) were ESBL positive, 29 strains (29%) were OXA-10 positive and 18 strains (18%) were PER-1 positive.

Conclusion: Our results confirm the need for proper antimicrobial therapy in burn hospitals, considering the resistance pattern and frequency of strains producing ESBLs and the presence of the OXA-10 and PER-1 genes. Since an increase in the prevalence of ESBL in P. aeruginosa strains might lead to the transfer of these ESBL genes to other gram-negative bacteria, we recommend the use of appropriate drugs, especially cephalosporins, in burn hospitals.

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Background: Pseudomonas aeruginosa is an important opportunistic pathogen causes clinical infections among burn patients. Metallo-β-lactamases (MBLs) are important mechanisms of Carbapenem (drug of choice) resistance among Pseudomonas aeruginosa isolates. The aims of this study were to determine the antibiotic susceptibility pattern and to detect the prevalence of MBLs among Pseudomonas aeruginosa
Methods: Initially, the antibiotic resistance patterns of 170 clinical strains isolated from burn patients in Motahari Hospital in Tehran, Iran were determined by Kirby-Bauer disc diffusion method. All of the clinical isolates using two phenotypic and genotypic methods.  Pseudomonas aeruginosa isolates resistant to Imipenem were screened for production of MBL by E test with Imipenem / Imipenem plus EDTA (E test MBL). PCR assay was performed for detection of blaVIM genes.
Results: Based on the study results, the percentage of resistance was as below: Imipenem (10 μg) 52.9%, Amikacin (30 μg) 81.7%, Carbenicilin (100 μg) 74.7%, Polymixine B (300 unit) 10%, Ticarcilin (75 μg) 84.7%, Tobramycin (10 μg) 88.2%, Colisitin (10 μg) 34.1, Colisitin (25 μg) 28.3%. Of 90 Carbapenem resistant isolates, 10(11/1%) isolates were positive by E test, all were sensitive to Colisitin and Polymixine B. All of the Imipenem resistant Pseudomonas aeruginosa isolates were examined by PCR for the presence of the blaVIM genes. All MBL-producing isolates carried blaVIM-1 genes.
Conclusion: Considering the high prevalence and clinical importance of MBL-producing isolates, rapid identification of them and use of the appropriate infection control measures are necessary to prevent further spread of infections by these organisms.