Investigation of nosocomial infection caused by arbekacin-resistant, methicillin-resistant Staphylococcus aureus.

An outbreak of coagulase VII-producing, arbekacin (ABK)-resistant, methicillin-resistant Staphylococcus aureus (MRSA) occurred between September 1994 and December 1995, involving five different wards. Twenty-one patients developed skin, wound, drainage, or respiratory tract colonization with coagulase VII-producing, (ABK)-resistant MRSA. Phenotypic characteristics (production of enterotoxin and TSST-1, antimicrobial susceptibility) and molecular-typing procedure (plasmid DNA profile, pulsed-field gel electrophoresis [PFGE] and arbitrarily primed polymerase chain reaction [AP-PCR] of chromosomal DNA) in isolated strains were compared. Plasmid analysis identified four different profiles and 19 of 22 strains recovered had identical patterns. PFGE of chromosomal DNA identified three different subtypes and 18 (81.8%) isolates shared the same subtype. AP-PCR also demonstrated that most strains had the same phenotypic characteristics. Although traditional epidemiological methods; for example, coagulase typing, plays a central role in hospital infection control, combination of plasmid DNA profile, AP-PCR, and PFGE may prove to be a particularly informative means of tracking the nosocomial spread of MRSA.

Breast conserving treatment versus modified radical mastectomy in Japanese patients with operable breast cancer.

From January, 1988 to October, 1995, 96 patients with operable breast cancer were treated by breast conserving treatment (BCT) including wide excision and axillary dissection followed by breast radiation. During the same period, 188 patients were treated by modified radical mastectomy (MRM) with or without breast reconstruction. In order to compare the survival of BCT and MRM groups, univariate and multivariate analyses were performed in this retrospective study. Univariate analysis revealed that the 5-year survival rates in the BCT and MRM groups were 97% +/- 2% and 87% +/- 3%, respectively (p < 0.05 with the Cox-Mantel test). However, the baseline variables were different between the groups. The adjusted Cox regression analysis revealed that the results of BCT were almost equivalent with those of MRM. Moreover, no breast recurrence was found in the BCT group. Therefore, it is suggested that our technique of BCT is as effective as modified radical mastectomy in treating operable breast cancer in Japanese patients.

Pathologic Assessment of Surgical Margins on Frozen and Permanent Sections in Breast Conserving Surgery.

The diagnostic value of frozen section was evaluated in the histologic assessment of surgical margins obtained by wide excision of breast tumors. There were 87 patients with unilateral breast cancer, and 5 with bilateral breast cancers. The periphery of the excised breast tissue was peeled like an orange and histologically examined by frozen and permanent section. If either in situ or infiltrating microscopic tumor was found at the margin, it was considered positive. Using frozen sections, the margin was judged histologically positive or suspicious in 30 tumors (31%) and negative in 67(69%) tumors. Positive surgical margins were histologically confirmed by permanent section in 20(67%) of the 30 tumors diagnosed as positive or suspicious on frozen section. Another 10 tumors had negative margins. In 4 tumors, however, while the initial or re-excised margin was negative on frozen section, the margins were positive by permanent section. These surgical margins were positive due exclusively to the presence of ductal carcinoma in situ (DCIS). Evaluation of surgical margins in breast cancer by frozen section, thus exhibited a diagnostic accuracy of 86&prtcnt;, a sensitivity of 83%, and a specificity of 86%. It is concluded that frozen sections are useful in the determination of involvement of surgical margins after the wide excision of breast cancer. It must be pointed out that frozen sections will ofter overestimate involvement of the surgical margins.