BACKGROUND: Gram-negative bacilli can be stored in cystine tryptic agar (CTA) at room temperature for over 1 year, but we experienced a loss of imipenem resistance among VIM-2-producing isolates. The aims of this study were to determine the frequency of loss of IMP-1 and VIM-2 genes during storage in CTA at room temperature and to document any change in the MIC of antimicrobial agents and the location of the gene. METHODS: Bacteria were isolated from clinical specimens at Severance Hospital collected from 1995-2000. Modified Hodge and double disk synergy tests were performed for screening of MBL-production isolates, and blaIMP-1 and blaVIM-2 were detected by PCR. Loss of resistance was tested in CTA at room temperature. PFGE and hybridization using a blaVIM-2 probe were carried out to determine the location of the VIM-2 gene. RESULTS: When VIM-2- and IMP-1-producing strains of eight P. aeruginosa and two Acinetobacter spp. were stored in CTA at room temperature, some isolates lost imipenem resistance after 3 days and 90% lost resistance after 15 weeks. Loss of resistance genes resulted in a decrease of the MIC of imipenem from 32-128 mug/mL to 0.5-8 mug/mL for P. aeruginosa, and from 32 mug/mL to 0.25-4 mug/mL for Acinetobacter spp. Hybridization of I-CeuI and S1-digested and PFGE suggested that VIM-2 genes are located on approximately 50-100 kb or 400 kb plasmids. CONCLUSION: Isolates may lose resistance genes when stored in CTA at room temperature. Therefore, it is necessary for MBL-production tests including the Modified Hodge test and double disk synergy test and detection of MBL genes.
Acinetobacter ; Agar ; Anti-Infective Agents ; Bacteria ; Carbapenems ; Chimera ; Cystine ; Imipenem ; Mass Screening ; Polymerase Chain Reaction ; Sprains and Strains

Testicular or scrotal involvement has been reported in children with Henoch-Schonlein purpura (HSP), but there are very few reports on penile involvement. We report the initial and follow-up ultrasonographic findings of scrotal and penile involvement of HSP in a 5-year-old boy. On ultrasonography, scrotal soft tissue thickening and epididymal swelling with increased vascularity were noted, and on the penis, a focal mass-like lesion appeared on the dorsal surface of the distal penis, having a hypoechoic mass-like appearance without visible vascular flow on a Doppler study. After 2 days of treatment, follow-up ultrasonography showed normal scrotum and penis with a resolved soft tissue mass-like lesion. Therefore, we think that HSP ultrasonographic findings involving the scrotum and penis might help to diagnose scrotal and penile involvement in a case of HSP and to avoid unnecessary medication and/or surgical procedures.
Child ; Child, Preschool ; Follow-Up Studies ; Humans ; Male ; Penis ; Purpura, Schoenlein-Henoch* ; Scrotum ; Ultrasonography*