[Evaluation of a newly developed broth microdilution test method to determine minimum inhibitory concentrations (MICs) of antimicrobial agents for mycobacteria]

We developed a new broth microdilution antimycobacterial susceptibility test for determination of minimum inhibitory concentration (MICs) using an air-dried microplate containing serially diluted antimicrobial agents and the modified Middlebrook 7H9 broth. The eight agents included were streptomycin (SM), isoniazid (INH), rifampicin (RFP), ethambutol (EB), kanamycin (KM), levofloxacin (LVFX), sparfloxacin (SPFX) and clarithromycin (CAM). Serial dilutions of the agents (128 micrograms/ml to 0.125 micrograms/ml) were prepared in microplates, and were reconstituted by inoculation of 0.2ml of cell suspensions (approximately 3 x 10(5) cells/ml). The test plates were incubated at 36 degrees C in 5% CO2, and the growth endpoints were read visually after 5-day, 7-day and 10-day incubations. Four ATCC reference strains, Mycobacterium tuberculosis, M. avium, M. kansasii and M. intracellulare, were repeatedly tested at three sites. Of 480 determination against eight agents, 455 (94.8%), 470 (97.9%) and 455 (94.8%) of the MICs read after 5-day, 7-day and 10-day incubations fell within 3log2 dilutions, respectively. The MICs gradually elevated during the incubation, however those of 7-day incubation were highly precise and easily determined. A total of 160 clinical isolates of M. tuberculosis and 114 of nontuberculous mycobacteria were tested against eight agents. As for the primary drugs (SM, INH, RFP and EB), most isolates of M. tuberculosis were highly susceptible with MIC90, < or = micrograms/ml. Both LVFX and SPFX were also active. The MICs against nontuberculous mycobacteria distributed in a wide range, and the activities of RFP, LVFX, SPFX and CAM were more potent. These results demonstrate this newly developed test method to be a practical, rapid, quantitative and nonradiometric alternative for the determination of MICs in clinical mycobacteriology laboratories.

[Determination of pyrazinamide susceptibility for Mycobacterium tuberculosis by use of Middlebrook culture media and comparison with results of pyrazinamidase test]

We developed a new test method to determine pyrazinamide (PZA) susceptibility for Mycobacterium tuberculosis in an acidified Middlebrook 7H9 broth (pH6.0), and evaluated in comparison with the agar proportion method of the National Committee for Clinical Laboratory Standards (NCCLS) M24-T and with pyrazinamidase assay. The test method is based on a culture in 4 ml of the modified Middlebrook 7H9 broth containing 100, 200 and 400 micrograms PZA/ml, respectively. First, the cell suspension was adjusted to a McFarland #1 turbidity, and then diluted 1:10. After mixing, 0.1 ml of the diluted cell suspension was inoculated and incubated at 36 +/- 1 degrees C in an ambient air. After 7 day-incubation, the test broth was read in comparison with the growth control. When a significant growth at 100 micrograms PZA/ml or an attenuated growth at 100 micrograms PZA/ml but a significant growth at 400 micrograms PZA/ml were observed, the test isolate was interpreted as being PZA-resistant. When PZA-susceptible and PZA-resistant ATCC reference strains were repeatedly tested, the results obtained were highly precise and accurate. A total of 65 clinical isolates were tested, the results indicating 95.4% of agreements with the agar proportion method and 90.8% with pyrazinamidase assay. There found six discrepant results of 13 resistant isolates; three were susceptible by the agar proportion and all the six were positive by pyrazinamidase assay. Accordingly, we can conclude that, in place of radiometric Bactec System, our newly developed test method is an accurate, practical, rapid and nonradiometric alternative to determine PZA susceptibility for M. tuberculosis in clinical mycobacteriology laboratories.

[Enhanced induction of apoptosis of human colorectal cancer cells after preoperative treatment with 5-fluorouracil its relationship to DNA ploidy pattern]

We examined the relationship between apoptosis induced by 5-fluorouracil (5-FU) that was given preoperatively to colorectal cancer patients and DNA ploidy pattern, and investigated the cell cycle changes, and the expression of Ki-67. Twenty-nine patients with advanced colorectal cancer were divided into four groups, 3 days, 5 days, 7 days, and 10 days. Groups received continuous intravenous 5-FU at 500 mg/body/day preoperatively. Then, patients were divided into two groups by DNA ploidy pattern, diploid(D) and aneuploid(A). Apoptotic cells were stained by the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) method. The expression of Ki-67 was examined by immunohistochemical staining. We used flow cytometry (FCM) for analysis of cell cycle distribution. Apoptosis of cancer cells was mostly increased in 7 days 5-FU administration in both D and A groups. The expression of Ki-67 was reduced according to the prolongation of the term of 5-FU administration in both D and A groups. We assessed S-phase fraction (SPF) to evaluate the cell cycle changes by 5-FU. Tumor samples of all patients after injection of 5-FU showed S-phase accumulation. The ratio of SPF (after 5-FU/before 5-FU) was the highest in the 5-day 5-FU administration group in both D and A groups. We concluded that apoptosis and S-phase accumulation were increased, and proliferative activity was decreased by preoperative 5-FU administration in colorectal cancer patients. However, there was no clear correlation between DNA ploidy pattern and these changes.

Systemic lupus erythematosus (SLE) lymphadenopathy presenting with histopathologic features of Castleman' disease: a clinicopathologic study of five cases

Lymph node enlargement is common in active systemic lupus erythematosus (SLE), a disease characterized by well defined clinical criteria. Although numerous reports have described the characteristic histology of SLE lymphadenopathy to include necrotizing lesions and hematoxylin bodies, no detailed description has examined the histopathologic features that are similar to Castleman's disease (CD) in SLE patients. In this report, we describe the clinicopathologic findings of CD-like peripheral lymphadenopathy, which was identified in five (26%) of 19 SLE patients. These five patients were all female with an age range of 24 to 44 years, and four of them presented with multicentric lymphadenopathy. They also had systemic symptoms and abnormal laboratory findings, indicating active disease, although two patients had not fulfilled the diagnostic criteria of SLE at the initial disease. The size of the enlarged lymph nodes seldom exceeded 2.0 cm in diameter, and biopsies revealed histopathologic features similar to CD, of intermediate type in three patients and hyaline vascular type in two according to the classification of Flendrig [7]. Immunohistochemical studies demonstrated polyclonal plasma cell populations in all five cases. Epstein-Barr virus genomes were detected in the small lymphocytes of two of the three cases examined by in situ hybridization studies. Recently, the histopathologic findings of CD have been associated with a disrupted immune response, and the present data suggest that SLE should be listed as one of the diseases showing the histopathologic features similar to CD.

[Inactivated influenza virus vaccine: the status quo and several new approaches for future application]

Inactivated influenza vaccines were first developed in the 1930s and then, more efficient methods of virus purification and disruption have led to less toxic vaccine, e.g. HA-split vaccine. A program of annual immunization to schoolchildren had been recommended in Japan since 1960. This assumed that the high incidence of influenza morbidity among schoolchildren might play a role in extending influenza in general population. However, due to the lack of detailed data, the public had bee reluctant to accept, especially for healthy children. Accordingly, the Japanese government changed its policy to vaccinate on demand, which resulted in a marked decrease of vaccinees. Several alternative approaches are in progress to produce more efficient vaccines. DNA vaccine, plasmid DNA encoding influenza peptides, seems promising for future application. However, as it will take more years for clinical evaluation, it is urgent to design a protocol to estimate cost-effectiveness of the presently available inactivated vaccine.

[Determination of in vitro synergy when amphotericin B is combined with various antimicrobial agents against yeasts by using a colorimetric microdilution checkerboard]

We determined in vitro interactions when amphoteric B (AMPH) is combined with various antimicrobial agents against yeast by using a colorimetric microdilution transfer plate technique, principally based on the current National Committee for Clinical Laboratory Standards (NCCLS) M27-T. An oxidation-reduction dye, sodium resazurin, was used as a color indicator to detect the growth of yeasts, and a standard two-dimensional, two-agent microdilution checkerboard in RPMI 1640 was employed to determine in vitro interactions; synergistic, indifferent or antagonistic. The study included 125 clinical isolates of Candida species and nine reference strains of American Type Culture Collection described in M27-T. Among the 34 antimicrobial agents first tested, polymyxin B (PL), rifampicin (RFP), tetracycline (TC) and erythromycin (EM) showed significant synergism. The fractional inhibitory concentration (FIC) indices of the respective agents were; PL 0.16 to 0.51 (mean, 0.315), RFP 0.13 to 0.56 (0.255), TC 0.06 to 0.75 (0.353) and EM 0.27 to 1.0 (0.550). RFP was the most potent agent, 118 of 125 clinical isolates (94.4%) showing synergism (FIC, < or = 0.5). With these results, we can conclude that several antibacterial agents are potentially effective when combined with AMPH against yeasts, probably due to alteration in the permeability barrier of the surface membrane by AMPH. Antifungal synergism may be promising for more effective, and less toxic therapy, and thus in vivo study will be necessary to determine their clinical significance.

[Effects of globulin preparations on phagocytic killing of oral streptococci]

The phagocytic bacterial activity on Streptococcus intermedius and Streptococcus oralis, clinical isolates from patients suffering from severe oral surgical infections, was evaluated by using sera and neutrophils of patients who had been treated with polyethylene glycal treated human normal immunoglobulin (Venoglobulin-IH). The phagocytic function of the neutrophils against the two strains, approximately 10 cells/neutrophil, was unrelated to the administration of Venoglobulin-IH. The bactericidal function of the serum and neutrophils on the third day following Venoglobulin-IH administration, on the other hand, rose to 10 times that of the sera and neutrophils of patients with mild infections. The agglutinin titer of Venoglobulin-IH against S. intermedius and S. oralis were 32 and 16 times, respectively, indicating an evident rise in these titers against the clinical isolates in comparison with the reference strains of the same organisms. These findings indicated that the oral streptococci that are isolated from patients with grave infections are associated with an antigenicity that is different from the normal bacterial flora; and these organisms are more labile to phagocytosis by neutrophils that were obtained from patients who have been treated with Venoglobulin-IH.

[Laboratory-evaluation of antimicrobial susceptibility testings to detect vancomycin-resistant enterococci]

The emergence and dissemination of vancomycin-resistant enterococci (VRE) emphasizes the need for laboratories to be able to correctly detect them. The study described was conducted to evaluate the test methods presently available in Japan to discriminate between the isolates of VRE and those susceptible (VSE). Among the phenotypic test methods evaluated, an agar screening method which utilized 8 micrograms per ml of vancomycin in Mueller-Hinton agar plate appeared to have a sufficient accuracy. When 23 isolates of vanA positive, 31 of vanB positive, 4 of both positive and 60 of both negative were tested, the sensitivity and specificity to detect VRE were estimated to be 98.3% and 100%, respectively. Also, all the VRE isolates were interpreted as being resistant or intermediate by the E test recently approved in Japan, when the results were read after 48 hr-incubation. Whereas, two disk diffusion tests, Showa disk and NCCLS-based Sensi-disc, were evaluated, but both methods failed to discriminate between VRE and VSE, in particular, between the isolates with vanB positive and negative. The automated system, Vitek GPS-TA produced high frequencies of very major errors; 8.7% for vanA positives and 58% for vanB positives. A total of 1,214 enterococcal isolates from multisite laboratories in Japan, comprising 7 different species, were first tested onto agar screening test plates, but none of isolates represented phenotypic vancomycin resistance. With these results, it can be recommended to detect VRE in clinical microbiology laboratories as follows: First, all the enterococcal isolates will be tested onto the agar screening plates or by the E test. Then, if the isolate is interpreted as being resistant or intermediate, the laboratory should confirm whether it is positive for vanA or vanB by polymerase chain reaction (PCR) specified.

[Multisite evaluation of a colorimetric broth microdilution antifungal susceptibility testing]

A new colorimetric microdilution antifungal susceptibility testing using an air-dried microplate containing serially diluted antifungal agents and an oxidation-reduction dye, sodium resazurin, as a color indicator to detect the growth of yeasts was evaluated at multiple sites. Six ATCC reference strains described in the National Committee for Clinical Laboratory Standards (NCCLS) M27-T, two quality control and four reference strains, were repeatedly tested against five antifungal agents, amphotericin B(AMPH), flucytosine (5-FC), fluconazole (FCZ), miconazole (MCZ) and itraconazole (ITZ) at 17 different laboratories. Of 1,521 MIC determinations, 1,393 (91.6%) were within the acceptable limits described in the M27-T, ranging from 23.8% to 100%. However, significant discrepancies from the M27-T limits were noted in some combinations, such as FCZ against C. albicans ATCC 90028. In addition, the MIC limits for MCZ and ITZ against the six reference strains were determined. A total of 1,645 clinical isolates of yeasts were tested against five antifungal agents. Most isolates of C. albicans were highly susceptible to the five agents with MIC90 ranging from 0.03 microgram/ml (MCZ) to 1.0 microgram/ml (AMPH). The MICs against AMPH and 5-FC were tightly clustered, except with C. krusei and Trichosporon spp. Whereas, the distribution of MICs for FCZ, MCZ and ITZ had a wide range from < or = 0.03 microgram/ml to > 64 micrograms/ml. From these results, it can be concluded that our colorimetric broth microdilution antifungal susceptibility test is reliable, easy-to-perform and a suitable alternative for the determination of the MICs in clinical microbiology laboratories.

[Determination of antimycobacterial activities of fluoroquinolones against clinical isolates of Mycobacterium tuberculosis: comparative determination with egg-based Ogawa and agar-based Middlebrook 7H10 media]

The minimum inhibitory concentrations (MICs) to the fluoroquinolones, ofloxacin (OFLX), ciprofloxacin (CPFX), sparfloxacin (SPFX), norfloxacin (NFLX), balofloxacin (BLFX) and CS-940, were determined in 100 clinical isolates of Mycobacterium tuberculosis. The MICs were determined with 1% egg-based Ogawa or agar-based Middlebrook 7H10 and each of them supplemented with oxidation-reduction color dye, 2,3-diphenyl-5-thienyl-(2)-tetrazolium chloride (STC) by using the microculture technique. The MICs determined with Ogawa medium were approximately two- to four-fold higher when compared to those determined with Middlebrook agar medium. The supplement with STC slightly increased the MICs, probably as a result of easily recognizing small initial colonies. Among the six fluoroquinolones, CS-940 and SPFX showed the greatest antimycobacterial activities with inhibition of 50% of all the isolates at the concentrations between 0.25 to 0.5 microgram/ml. OFLX, CPFX and BLFX followed in potency at 0.5 to 2.0 micrograms /ml. NFLX was less potent requiring 8 to 16 micrograms/ml to inhibit 50% of the isolates.

Imprint cytology of cat scratch disease. A report of eight cases

The cytologic features of cat scratch disease (CSD) from eight cases in imprint smears are presented. All patients were clinicopathologically diagnosed with CSD as follows: 1) a history of animal exposure was recorded 2 to 4 weeks before lymphadenopathy; 2) the disease occurred in the autumn and winter months; 3) a characteristic histopathology in the biopsied lymph node specimens was observed; and 4) Warthin-Starry silver stain-positive bacteria were detected in four of the seven cases examined. The characteristic cytologic finding was the presence of confluent epithelioid cells with nearby and central scattering of neutrophils against a background of polymorphic inflammatory cells. Furthermore, a varying number of medium-sized to large lymphoid cells with an appearance suggestive of monocytoid B lymphocytes (MBLs) were noted to be associated with the epithelioid cells. These cytologic findings closely paralleled the histologic patterns of epithelioid cell granulomas, with and without MBLs, which we have previously reported are probably associated with the disease.

Multicenter evaluation of a colorimetric microplate antimycobacterial susceptibility test: comparative study with the NCCLS M24-P

A colorimetric test method using the microplate culture technique for the determination of susceptibility of Mycobacterium tuberculosis against antimycobacterial agents was developed and evaluated by the multicenter study. The test method utilizes an oxidation-reduction dye, 2,3-diphenyl-5-thienyl-(2)-tetrazolium chloride (STC), as an indicator of mycobacterial growth. When compared to the presently available test method, some modifications were also included; lower inoculum density (10-fold dilution), inclusion of an inoculum diluted 1:100 as a growth control, and the preparation of inoculum preincubated in Middlebrook 7H9 broth and spectrophotometrically adjusted to McFarland #1 turbidity. The test method evaluated was highly precise and reliable to detect antimycobacterial resistances when the ATCC reference strains were tested. Also, the interpretations of the test result were highly comparable to those determined by the method of NCCLS M24-P, the % agreements ranging from 76.1% (ethambutol) to 91.3% (streptomycin). The test results were also comparable to those determined by Ogawa media; > 90% agreed with susceptible, intermediate, or resistant. The appearance of mycobacterial colonies on the test media was easily read, and the test results were more comparable to those of NCCLS M24-P. With these results, it can be concluded that the colorimetric microplate susceptibility test method described will be more suitable for clinical mycobacteriology laboratories.

[Colorimetric broth microdilution for antifungal susceptibility testing]

A colorimetric broth microdilution modification of the National Committee for Clinical Laboratory Standards (NCCLS) for antifungal susceptibility testing was developed and evaluated. The test method modification includes; air-dried microdilution trays, in which serial two-fold dilutions of three antifungal agents, amphotericin B (AMPH), flucytosine (5-FC) and fluconazole (FCZ) were first prepared and evaporated, then reconstituted by adding 100 microliters of yeast inocula, and an oxidation-reduction color indicator (sodium resazurin, Sigma) added to RPMI 1640 medium buffered to pH7.0 with 0.165M morpholinepropanesulfonic acid. The trays were incubated in air at 35 degrees C and were inspected after 24 and 48hr of incubation. The MICs were defined as the lowest concentration of the respective agents; no color change (blue) for AMPH, and slight color change (blue to purple) for 5-FC and FCZ. The MICs of AMPH, 5-FC and FCZ were determined for four reference strains and 100 clinical isolates, in comparison with the NCCLS macrodilution method. The four reference strains were tested seven times each by macrodilution method (MACRO) and 14 times each against all three antifungal agents by microdilution method (MICRO). Overall, 100% of MICs determined by MACRO, 96% of those determined at 24hr incubation by MICRO, and 93% of those determined at 48hr incubation by MICRO fell within the 3-log2 dilutions, although 20 to 33% were out of the acceptable MIC ranges of the NCCLS M27-P proposal. Excellent reproducibility in determining growth endpoint by color change was also demonstrated, giving 99 to 100% agreements in duplicated dilutions. When the MICs determined for 100 clinical isolates against three antifungal agents were compared, those determined at 24hr incubation by MICRO gave 61.7% of agreement within the 3-log2 dilutions of the NCCLS MACRO, and those determined at 48hr incubation by MICRO were 86.2%. The MICRO read at 24hr trended to the lower MICs, except for 5-FC. While the MICs of MICRO read at 48hr were mostly comparable (78 to 97% agreement) to those of MACRO, especially against 5-FC (97%) and AMPH (85%), but the discrepant MICs of Candida tropicalis against FCZ were noted. With these results, it can be concluded that the resazurin colorimetric broth microdilution method is easy to perform and highly precise, and may provide MICs comparable to those determined by the reference NCCLS macrodilution method.

[Comparative clinical study of azithromycin with tosufloxacin tosilate in the treatment of acute odontogenic infection]

To objectively assess azithromycin (AZM) for its clinical efficacy, safety and usefulness in the treatment of acute odontogenic infections (periodontitis, pericoronitis and osteitis of the jaw), a double-blind, randomized, multi-center trial was conducted in which tosufloxacin tosilate (TFLX) was used as the control drug. AZM was administered to 90 patients at a once-daily 500 mg dose for 3 days, while TFLX was given to 90 patients at a 150 mg t.i.d. dose for 7 days. 1. The clinical efficacy rates calculated according to evaluation at an endpoint set on the 3rd day of treatment by a committee of experts were 85.9% (73/85) in the AZM group and 78.9% (71/90) in the TFLX group. No statistically significant difference between the treatment groups was detected, and clinical equivalence was verified (p = 0.002). 2. The clinical efficacy rates according to evaluations made by investigators at the end-of-tail point was 87.1% (74/85) in the AZM group and 73.3% (66/90) in the TFLX group. The efficacy rate in the AZM group was higher than that in the TFLX group, and the difference was statistically significant (p = 0.006). 3. The bacteriological elimination rate in the AZM group was 97.5% (39/40) and that in the TFLX group was 85.7% (30/35), but the difference was deemed statistically not significant. 4. Adverse reactions were observed in 11 of 88 cases (12.5%) in the AZM group and 5 of 90 cases (5.6%) in the TFLX group. Six of 85 cases (7.1%) in the AZM group and 5 of 85 cases (5.9%) in the TFLX group showed laboratory abnormalities. However, neither adverse reactions nor laboratory abnormalities showed any differences in statistical significance between the treatment groups. 5. The safety rates, expressed as percentages of cases with no adverse events and no laboratory abnormalities, was 84.1% (74/88) in the AZM group and 90.0% (81/90) in the TFLX group. The difference between the two groups was found to be statistically insignificant. 6. The usefulness rates, the ratio of cases rated as either "Very useful" or "Useful", was 83.9% (73/87) in the AZM group, and it was statistically higher (p = 0.025) than 72.2% (65/90) obtained for TFLX group. Judging from the above results, it has been concluded that AZM is as useful as TFLX in the treatment of acute dental infections.

[Multi-center evaluation to discriminate between the strains of methicillin-resistant Staphylococcus aureus (MRSA) and those susceptible (MSSA) by Showa oxacillin and methicillin disk susceptibility tests]

The Showa disk susceptibility test using two penicillinase-resistant penicillins, oxacillin and methicillin, was evaluated to discriminate between the strains of Staphylococcus aureus resistant to methicillin (MRSA) and those susceptible (MSSA) in the multi-center trials. The study included 651 clinical isolates of S. aureus, comprising of 329 MRSA and 322 MSSA isolates. The inhibitory zone diameters by Showa disks to oxacillin and methicillin highly correlated with minimum inhibitory concentrations (MICs) determined by standard agar dilutions with 0.961 and 0.930 correlation coefficients, respectively. Of 651 duplicate MIC determinations, 79.9% (oxacillin) and 80.3% (methicillin) were within +/- 1 log2 dilutions with each other. When Showa oxacillin and methicillin disks were incubated at 35 degrees C, sensitivity and specificity of oxacillin to detect MRSA were 95.4% and 98.1%, and those of methicillin were 94.8% and 95.2%. When tested on agar plates supplemented with 5% NaCl, sensitivity and specificity markedly improved to > 97%. Also, when incubated at 30 degrees C, sensitivity and specificity became to nearly 100%. Of 329 MRSA isolates, the interpretive criteria combined with incubation at 30 degrees C and testing onto 5% NaCl supplemented agar plates could correctly identify 324 (98.5%) and 329 (100%) isolates, respectively. In conclusion, when the Showa oxacillin and methicillin disk susceptibility tests were employed exactly according to the manufacturer's instruction, the test performances to detect MRSA were enough reliable to screen MRSA isolates in clinical microbiology laboratories.

Levofloxacin in vitro activity: results from an international comparative study with ofloxacin and ciprofloxacin

Levofloxacin, the S-(-)-isomer of ofloxacin, was compared to ofloxacin and ciprofloxacin against > 6000 recent clinical isolates of Gram-positive and Gram-negative bacteria from six different countries. This international multicenter study demonstrated a high level of antibacterial activity of levofloxacin against all the members of Enterobacteriaceae [minimum inhibitory concentration (MIC)50s, < or = 0.03 to 0.12 mg/L] except Providencia rettgeri (MIC50, 2 mg/L), and Providencia stuartii (MIC50, 1 mg/L). Oxacillin-susceptible staphylococci (MIC50s, 0.12 to 0.25 mg/L), enterococci (MIC50s, 0.5 to 2 mg/L), and streptococci (MIC50s, 0.5 mg/L) were also susceptible to levofloxacin, but most isolates of oxacillin-resistant staphylococci had MICs of > or = 4 mg/L. Levofloxacin was also active against non-enteric Gram-negative bacilli, including Acinetobacter species (MIC50s, < or = 0.03 to 1 mg/L), Pseudomonas species (MIC50s, 0.5 to 1 mg/L) and Xanthomonas maltophilia (MIC50, 0.5 mg/L). Overall, levofloxacin inhibited 50% and 90% of all the tested strains at the concentrations of 0.12 and 4 mg/L, respectively. The activity of levofloxacin was generally two-fold greater than ofloxacin and equal to or slightly less potent than ciprofloxacin.

[Multi-center evaluation of Showa ceftizoxime disk susceptibility test to discriminate between the strains of methicillin-resistant Staphylococcus aureus (MRSA) and those susceptible (MSSA)]

An increasing prevalence of methicillin-resistant Staphylococcus (S.) aureus (MRSA) has a serious therapeutic problem, and accurate methods to detect such strains are needed. We studied the antimicrobial susceptibility of S. aureus to ceftizoxime, in comparison with those to four other cephems (cefazolin, cefoxitin, latamoxef and cefmenoxime), by broth microdilutions and disk susceptibility tests, and also evaluated whether the reagents, in replace of penicillinase-resistant penicillins (PRPs), could discriminate between the strains of MRSA and those susceptible to PRPs (MSSA). A total of 651 clinical isolates of S. aureus were collected from six geographically different hospitals. All the strains collected were first classified into either MRSA (n = 329) or MSSA (n = 322) according to the interpretations of MRSA screening agar, minimum inhibitory concentrations (MICs) to oxacillin and methicillin (NCCLS M7-A2), and the presence or absence of mecA gene by polymerase chain reaction. In broth microdilution tests, the MICs of MRSA to ceftizoxime ranged > or = 64 micrograms/ml, whereas all the MSSA were at the concentration of < or = 16 micrograms/ml. The results of Showa disk diffusion tests highly correlated with those of MIC determinations. The distribution of inhibitory zone diameters to ceftizoxime were clearly divided into two groups; 99.2% (sensitivity) of MRSA had inhibitory zones of < or = 20 mm and 98.9% (specificity) of MSSA produced > or = 21 mm. It was concluded that the Showa ceftizoxime disk susceptibility test was useful and enough reliable to screen MRSA isolates in clinical laboratories.

Antimicrobial activity of FK-037, a new broad-spectrum cephalosporin. International in vitro comparison with cefepime and ceftazidime

The in vitro activity of FK-037, a new parenteral 7-aminothiazolyl-methoxyimino cephalosporin, was compared with cefepime and ceftazidime against 6094 aerobic isolates collected in six medical centers worldwide. FK-037 demonstrated potent activity against the Enterobacteriaceae family except for some Enterobacter spp., Providencia spp., and Serratia liquefaciens (MIC90s, > or = 16 micrograms/ml). Against nonenteric Gram-negative bacilli, all compounds tested showed similar, but more limited activity. The FK-037 MIC50s for Pseudomonas spp. and P. aeruginosa were 2 and 4 micrograms/ml, respectively. The least susceptible organisms were Xanthomonas maltophilia, enterococci, and Bacillus spp. (MIC50s, > 16 micrograms/ml), followed by Flavobacterium spp., other nonenterics, and oxacillin-resistant Staphylococcus aureus (MIC50s, 16 micrograms/ml). Good FK-037 activity was observed against oxacillin-susceptible staphylococci as well as against beta-hemolytic and viridans-group streptococci (MIC90 range, < or = 0.12 to 2 micrograms/ml). While FK-037 was slightly more active than cefepime against Gram-positive organisms, enteric bacilli were most susceptible to cefepime. Overall, the antibacterial spectrum of both FK-037 and cefepime was superior to ceftazidime.

In vitro activity of three carbapenem antibiotics. Comparative studies with biapenem (L-627), imipenem, and meropenem against aerobic pathogens isolated worldwide

The in vitro activity of biapenem (formerly L-627 or LJC10, 627), a new carbapenem, was compared with that of imipenem and meropenem against > 6000 clinically significant pathogens isolated in six countries worldwide. Biapenem was active against members of the family Enterobacteriaceae with a 90% minimum inhibitory concentration (MIC90) ranging from < or = 0.06 to 2 micrograms/ml. Only Serratia spp. and Providencia spp. were less susceptible (MIC90, 8 micrograms/ml). Pseudomonas aeruginosa and Xanthomonas maltophilia displayed an MIC90 of > or = 8 micrograms/ml biapenem/ml whereas Acinetobacter spp. were susceptible at < or = 1 micrograms/ml. Oxacillin-resistant staphylococci were resistant to biapenem at > 8 micrograms/ml whereas oxacillin-sensitive staphylococci were susceptible at < or = 1 micrograms/ml. Biapenem, imipenem, and meropenem displayed poor activity against Ent. faecium (MIC90, > or = 8 micrograms/ml), and only imipenem displayed slightly better activity against Ent. faecalis (MIC90, 4 micrograms/ml). The rank order of activity against groups of isolates was Enterobacteriaceae (meropenem > biapenem > or = imipenem), Ps. aeruginosa (biapenem = meropenem = imipenem), oxacillin-sensitive staphylococci (imipenem > or = biapenem = meropenem), oxacillin-resistant staphylococci (biapenem = meropenem = imipenem), and Enterococcus spp. (biapenem = meropenem = imipenem). These in vitro suggest that further developmental work on biapenem is warranted.

[Studies on the reduction and correction risk factors for arteriosclerosis in junior high school pupils]

Circulatory system examinations performed on first-grade pupils of junior high schools (12 years old; N = 1,204), identified 105 high-risk pupils with arteriosclerosis-promoting factors. These pupils were consulted on life-style modification, emphasizing nutrition and exercise, and encouraged to practice personal health management and self-monitoring. Reduction and correction of high risk factors were studied in these subjects, based on review of results of health examinations performed regularly up to the time of their graduation. Results are as follows: 1. Averages for obesity grade (for both sexes) in the second and the third years were significantly lower than that in the first year. Based on a general reference value > or = 20%, improvements were observed in 22.5% of males and 50.0% of females. 2. In both sexes average total cholesterol (TC) and triglyceride (TG) were lower in the second and the third years than in the first year, and a significant increase in HDL cholesterol was seen. With regard to a general reference value > or = 3.0 for AI (Atherogenic Index) calculated using TC and HDL cholesterol, improvements (reduction) were observed in 29.4%, of males and 46.2% of females. 3. While the numbers of subjects with elevated SBP, DBP, GPT, FPG and BUN were few, there were significant decreases in averages in the second and third years compared with those in the first year. Using general reference values, improvements in these risks were seen in 100% for all values except for GPT where 75.0% showed improvement. 4. Comparison of grouped distribution of summed values of examination results between the first year and the third year, showed improvements (reduction and correction of risks) in 69 pupils (65.7%), while 30 pupils (28.6%) remained in the same group with no improvement and 6 pupils (5.7%) turned for the worse, dropping one rank.(ABSTRACT TRUNCATED AT 250 WORDS)

Trivalent cold recombinant influenza live vaccine in institutionalized children with bronchial asthma and patients with psychomotor retardation

Twenty asthmatic children and 48 patients with severe psychomotor retardation were inoculated intranasally with trivalent cold-adapted recombinant (CR) influenza vaccine containing CR-125 (H1N1), CR-159 (H3N2) and CRB-117 (B). The vaccinees were mostly seropositive. Severe adverse reactions or asthmatic attacks were not observed, but 7 (15%) of 48 vaccinees with severe psychomotor retardation developed mild to moderate fever. Significant antibody responses in hemagglutination-inhibition tests were demonstrated in 33 (49%) vaccinees to CR-125, 20 (29%) to CR-159 and 8 (12%) to CRB-117. Two nosocomial outbreaks of influenza were observed in the subsequent winter. During an outbreak with H3N2 in one ward of severe psychomotor retardation patients, 2 (11%) of 18 vaccinees became infected compared with 10 (48%) of 21 placebo controls in the same ward (P < 0.05). In the other outbreak, with influenza B virus, 2 (14%) of 14 vaccinees and 13 (52%) of 25 controls in the ward for asthmatic children were infected (P < 0.05). The results indicate that trivalent CR vaccine is safe and effective against nosocomial outbreaks of influenza.

Prevalence of enterococcal high-level aminoglycoside resistance in Japan. Comparative detection by three methods

A total of 250 strains of enterococci isolated in Kumamoto University Hospital, Japan, during the period from January to March 1992 were tested for high-level aminoglycoside resistance. Brain-heart infusion (BHI) agar plates supplemented with 1000 micrograms/ml of gentamicin or 2000 micrograms/ml of streptomycin detected 164 (66%) isolates resistant to either gentamicin or streptomycin alone, or both, and consisted of 107 (43%) resistant to gentamicin and 96 (38%) resistant to streptomycin. The Vitek Gram-Positive Susceptibility card (GPS-TA) revealed high correlations with those by agar screens, the results indicating a sensitivity of 100% and 99% to gentamicin and streptomycin, respectively, and 100% specificity to both. Also, the microdilution tests of the National Committee for Clinical Laboratory Standards (NCCLS) showed 100% and 92% sensitivity to gentamicin and streptomycin, respectively, and no false resistance (100% specificity) when compared with the results by agar screens.

Immunization of institutionalized asthmatic children and patients with psychomotor retardation using live attenuated cold-adapted reassortment influenza A H1N1, H3N2 and B vaccines

Live attenuated cold-adapted reassortant (CR) influenza virus vaccines were evaluated in institutionalized asthmatic children and severe psychomotor-retarded (SPR) patients. Almost all the vaccinees were seropositive to the vaccine strains before immunization. Trivalent CR vaccine (containing A H1N1 (CR-125), A H3N2 (CR-149) and B (CRB-117)), bivalent CR vaccine (CR-125 and CR-149) and monovalent CRB-117 were inoculated to 19 asthmatic children and 36 and 16 SPR patients, respectively. Overall 49, 22, and 11% of vaccinees were infected by A H1N1, A H3N2 or B vaccine viruses, respectively, as indicated by significant haemagglutination-inhibition (HI) antibody titre rises 4 weeks after inoculation. No severe adverse reactions associated with CR vaccination were observed in the handicapped patients. A nosocomial outbreak of influenza A H1N1 occurred in the ward with asthmatic children, but none of the 19 CR-trivalent vaccinees became infected. However, five of 20 non-vaccinees in the same ward, and ten of 30 vaccinees in another ward that received inactivated split vaccine became infected. The CR vaccines demonstrated significant protective effects against natural exposure to the A H1N1 virus, and were well tolerated and safe when given to patients with bronchial asthma and severe psychomotor retardation.