The chemosensitivity test was developed to assess differences in chemosensitivity among tumors originating in the same tissue and of similar histological type. At the 30 th Annual Meeting of the Japanese Society for Appropriate Cancer Therapy, the overall accuracy of the chemosensitivity test was 74% for 1, 101 casee between 1994 and 1996 in Japan. However, only a partial response was recorded in the majority of cases, which does not result in any survival benefit. We believe that the chemosensitivity test is useful for evaluating appropriate adjuvant cancer chemotherapy regimens after surgery, enabling the tumor-burden to be reduced as much as possible. Further study has confirmed that molecular biological assays in which the mRNA of dihydropyrimidine dehdrogenase (a rate-limiting catabolic enzyme) and a membranous equilibrative nucleoside transporter are assessed, are useful for predicting the effect of 5-fluorouracil. The conventionally available chemosensitivity test is a whole cell assay, in which the whole cancer cells are directly incubated with antitumor agents. This assay allows ineffective antitumor agents to be eliminated from treatment regimens, and is applicable to newly developed antitumor agents, in which the mechanisms of resistance and the pharmacokinetics pharmacodynamics are unclear. The accuracy of the chemosensitivity test is almost equivalent to that of hormone receptor assays and bacillus sensitivity tests. When customized therapies become available, the chemosensititvity test will be widely used in clinics, when its used will be supported by national health insurance.

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We studied drug of genus Staphylococcus found in clinical materials in fiscal years 1998, 1999, and 2000 for vancomycin, teicoplanin, and arbekacin. For vancomycin, 1 isolate of Staphylococcus epidermidis derived from an inpatient in 1998 and 1999 was found to be resistant up to 8μg/mL. Two isolates of vancomycin-resistant Staphylococcus aureus (MRSA) to 4μg/mL were first found in 2000. For teicoplanin, 12 isolates and 18 isolates that showed resistance at≥16μg/mL wereobtained from Coagulase-negative Staphylococcus sp. in 1998 and 1999, and most were S. epidermidis. For arbekacin, 3 isolates in 1998, 7 isolates in 1999 and 13 isolates in 2000 were resistant at≥16μg/mL and many belonged to MRSA. The detection of genus Staphylococcus was about 25% in each of these 3 years. In genus Staphylococcus, MRSA accounted for the largest portion of about 40%, MSSA accounted for about 30%, and S. epidermidis accounted for about 20%.

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We studied the complication rate in 103 patients receiving rectal ultrasonography-guided systematic needle biopsy of the prostate when given a single (single-dose group) or 2 intravenous administrations (1-day group) of a prophylactic antimicrobial agent. Of these, 52 received a single administration and 51, 2 administrations, determined by the preference of the urologist in change. The single-dose group had a complication rate of 5.8%(3 patients) and the 1-day group, 5.9%(3 patients). Febrile complication of urinary tract infection developed in 1 patient (1.9%) in the single-dose group and in 1 (2.0%) in the 1-day group, not significantly different. Our results suggest that a single intravenous administration of an antimicrobial can be used as prophylaxis for febrile complication after biopsy.

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We examined 1, 843 patients, 1, 115 men and 728 women, undergoing gastrointestinal surgery during the last 10 years at our department to ascertain the gender difference in the incidence of postoperative infection and the isolation of MRSA. We found 608 (33.0%) postoperative infections, with MRSA isolated from 127 (6.9%). The incidence of postoperative infection in those contaminated during operations was 50.4%, that in the aged 42.3%, in malignant disease 37.7%, and in men 35.7%, all significantly higher than that in clean operations at 31.7%, in younger people at 29.6%, in benign disease at 27.3%, and in women at 28.8%. MRSA isolation in those contaminated during operations was 14.0%, that in the aged 10.5%, in malignant disease 8.6%, and in men 9.5%, all significantly higher than that in clean operations at 6.4%, in younger people at 5.6%, in benign disease at 4.8% and women at 2.9%. No significant difference was seen in the incidence of postoperative infection or MRSA isolation between groups with and without complication. The incidence of postoperative infection in men was significantly higher than in women in clean operations, the aged, and benign disease. Complication of postoperative infection was significantly higher in men than in women in both subgroups. MRSA isolation was significantly higher in men than in women in clean operations and without complications. In age and disease, MRSA isolation was significantly higher in men than in women in all subgroups, so we concluded that gender may be a risk factor in the outbreak of postoperative infection and MRSA isolation.

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Profiles of the expression of antimicrobial activities of rifalazil (previously known as KRM-1648), clarithromycin (CAM), and levofloxacin (LVFX) against Mycobacterium tuberculosis Kurono and Mycobacterium avium N-444 strains were studied. The number of residual bacterial CFU was estimated after cultivation of test organisms in 7HSF medium containing these drugs at C_max, at 37°C for up to 10 days. Rifalazil and LVFX both displayed potent microbicidal effect against the M. tuberculosis, and the number of residual bacterial CFU declined to below detectable within 3 to 5 days after the start of cultivation. CAM exerted moderate bactericidal activity against the M. tuberculosis during the first 5 days but bacterial regrowth was observed thereafter. Rifalazil rapidly killed the M. avium within 3 days, but subsequent progressive regrowth of organisms was observed. Both CAM and LVFX exhibited no more than a growth-inhibitory action against M. avium. These findings emphasize that M. avium is evidently less susceptible to these antimycobacterial drugs, particularly LVFX, than M. tuberculosis.

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Using the broth micro-dilution method, the susceptibility of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and enterobacteriaceae to meropenem (MEPM) and control agents was examined. All strains were isolated from blood samples obtained from patients admitted to Keio University Hospital between January 1999 and June 1999. An inoculum size of 10⁴cfu/mL was used.
1. MEPM showed excellent antibacterial activities against most blood culture isolates at our hospital, with the exception of a drug-resistant strain of staphylococci (MRSA, part of S. epidermidis). A comparison of the antibacterial activity of MEPM with that found in our previous studies showed no significant difference in the susceptibility of clinical isolates. Thus, MEPM retained its position as the drug of first choice for serious infections.
2. MEPM differed microbiologically from imipenem and panipenem by having a greater potency in vitro against many gram-negative pathogens, including P. aeruginosa, and an almost similar potency against many gram-positive pathogens. Thus, MEPM was considered to be the most potent agent among the 3 carbapenems studied.

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