Search

Although pandemic community-associated (CA-) methicillin-resistant Staphylococcus aureus (MRSA) ST30 clone has successfully spread into many Asian countries, there has been no case in Korea. We report the first imported case of infection caused by this clone in a Korean traveler returning from the Philippines. A previously healthy 30-yr-old Korean woman developed a buttock carbuncle while traveling in the Philippines. After coming back to Korea, oral cephalosporin was given by a primary physician without any improvement. Abscess was drained and MRSA strain isolated from her carbuncle was molecularly characterized and it was confirmed as ST30-MRSA-IV. She was successfully treated with vancomycin and surgery. Frequent international travel and migration have increased the risk of international spread of CA-MRSA clones. The efforts to understand the changing epidemiology of CA-MRSA should be continued, and we should raise suspicion of CA-MRSA infection in travelers with skin infections returning from CA-MRSA-endemic countries.

Since microbial gene sequencing was utilized for etiologic diagnosis of culture-negative endocarditis, cases of Bartonella endocarditis have been reported in various countries. Herein we report the first case of Bartonella quintana endocarditis, which was confirmed for the first time in Korea by 16S rRNA gene sequencing from the excised valve. A 75-yr-old woman was hospitalized due to dyspnea. Echocardiography demonstrated large oscillating vegetation at the aortic valve. Blood culture was negative. She underwent valve replacement and sequencing of the 16S rRNA gene from excised valve identified Bartonella quintana. She was successfully treated with combined use of ceftriaxone and gentamicin.

While ica gene of Staphylococcus epidermidis is known to undergo phase variation by insertion of IS256, the phenomenon in Staphylococcus aureus has not been evaluated. Six biofilm-positive strains were tested for the presence of biofilm-negative phase-variant strains by Congo red agar test. For potential phase-variant strains, pulsed-field gel electrophoresis was done to exclude the possibility of contamination. To investigate the mechanism of the biofilm-negative phase variation, PCR for each ica genes were done. Changes of ica genes detected by PCR were confirmed by southern hybridization, and their nucleotides were analyzed by DNA sequencing. Influence of ica genes and biofilm formation on capacity for adherence to biomedical material was evaluated by comparing the ability of adhering to polyurethane surface among a biofilm-negative phase-variant strain and its parent strain. A biofilm-negative phase-variant S. aureus strain was detected from 6 strains tested. icaC gene of the phase-variant strain was found to be inactivated by insertion of additional gene segment, IS256. The biofilm-negative phase-variant strain showed lower adhering capacity to polyurethane than its parent strain. This study shows that phase variation of ica gene occurs in S. aureus by insertion of IS256 also, and this biofilm-negative phase variation reduces adhering capacity of the bacteria.

The aim of this study was to investigate the adjuvant effects of interferon-gamma (IFN-gamma) inhalation therapy for six months in the treatment of refractory multidrug-resistant pulmonary tuberculosis (MDR-TB). Aerosolized IFN-gamma was given to six MDRTB patients with persistent positive smears and cultures despite long-term medical treatment. The patients received aerosolized two million international units of IFN-gamma three times a week for 6 months while they continued on identical antituberculous chemotherapy. Before IFN-gamma inhalation therapy, the patients received a median of 6.5 (range, 4 to 7) antituberculous drugs for median duration of 29 months (range,7 to 76). After IFN-gamma inhalation therapy, sputum smears remained persistently positive in all patients throughout the study period. Sputum cultures were transiently negative at the 4th month in two patients, but became positive again at the end of 6 months of IFN-gamma therapy. Five patients had radiological improvement including three patients who showed a decrease in the size of the cavitary lesions. Resectional surgery could be performed in one patient in whom substantial clinical and radiological improvement was noted after IFN-gamma inhalation therapy. These results suggest that IFN-gamma inhalation therapy may be effective for some cases of refractory MDR-TB who are otherwise not responding to conventional therapy.