We evaluated a monoclonal fluorescent-antibody (FA) reagent (Neisseria gonorrhoeae Culture Confirmation Test; Syva Co., Palo Alto, Calif.) for confirmation of N. gonorrhoeae isolates obtained from clinics for sexually transmitted diseases in four cities. The FA test was performed in parallel with established confirmation procedures on all organisms growing on 773 primary culture plates of modified Thayer-Martin agar. All N. gonorrhoeae isolates reacted with the FA reagent and produced a bright, easily interpretable fluorescence. The FA test correctly identified 533 N. gonorrhoeae isolates from 474 patients and did not react with 90 N. meningitidis or with 213 non-Neisseria isolates. In one city (Baltimore), Gonochek II (Du Pont Co., Wilmington, Del.) failed to identify four N. gonorrhoeae isolates reactive with the FA reagent and confirmed as N. gonorrhoeae by Phadebact (Pharmacia Inc., Piscataway, N.J.) and acid production from sugars. The FA test was rapid and specific and could be performed directly from primary isolation plates. The test requires 1 h to perform and is applicable to mixed-flora cultures.

The growth-inhibitory effect of cefmenoxime against Proteus vulgaris was studied by using the broth dilution and paper disk diffusion methods. Cefmenoxime showed growth-inhibitory activity against Proteus vulgaris at low concentrations but not at high concentrations up to a certain limit. This paradoxical antibacterial activity was not observed with cefoperazone and cefbuperazone. The induction of I8-lactamase by cefmenoxime and the rate of hydrolysis of cefmenoxime in the culture broth were proportional to the initial concentration of this antibiotic. At high initial concentrations, cefmenoxime was rapidly inactivated. On the other hand, neither cefoperazone nor cefbuperazone was inactivated irrespective of concentration. We conclude that cefmenoxime induces I8-lactamase in P. vulgaris, perhaps accounting for its paradoxical antibacterial effect.Cefmenoxime (CMX) is one of the new type of cephalosporins which have excellent antibacterial activity against gram-positive and gram-negative bacteria including Proteus vulgaris (10). However, like cefotaxime and cefotiam, CMX is comparatively unstable to 13-lactamase produced by P. vulgaris (10).In 1948, Eagle and Musselman (2) reported that the antibacterial activity of penicillin G against gram-positive cocci was paradoxically reduced as its concentration was increased. Similar phenomena against gram-positive cocci have been reported by others (9, 16). This effect is generally known as the "Eagle effect." Regarding gram-negative bacteria, a paradoxical effect of mecillinam against Providencia stuartii was reported in 1976 (4). However, the mechanism of this paradoxical effect has not been explained sufficiently.In studying the antibacterial activity of P-lactam antibiotics, we observed an interesting phenomenon in P. vulgaris: whereas growth was found in the presence of CMX at high concentrations, no growth occurred at low concentrations. This paper deals with the paradoxical effect of CMX on P.vulgaris.MATERIALS AND METHODS Antibiotics. CMX, prepared by Takeda Pharmaceutical Co., Ltd., Osaka, Japan, and cefoperazone (CPZ) and cefbuperazone (CBPZ), both prepared by Toyama Chemical Co., Ltd., Tokyo, Japan, were used as test antibiotics.Bacterial strains. The strains of P. vulgaris used in this study were all derived from clinical materials obtained in Japan.Paradoxical effect of drugs. (i) Broth dilution method. A series of tubes containing doubling dilutions of antibiotics in sensitivity broth (Eiken Chemical Co., Ltd., Tokyo, Japan) were inoculated with P. vulgaris at an inoculum size of 106 cells per ml. The tubes were incubated at 37°C for 18 h, and visible growth was observed.(ii) Paper disk method. Sensitivity disk agar (Eiken Chemical Co., Ltd.) molten at 45°C was inoculated with organisms * Corresponding author. Preparation of I8-lactamase. An overnight culture in brain heart infusion broth (Difco Laboratories, Detroit, Mich.) was diluted 10-fold with the same medium and incubated with shaking at 37°C for 2 h. Then 10 ,ug of cefmetazol per ml was added as ...

To assess the practical significance of reported increases in the prevalence of vancomycin-susceptible strains of Neisseria gonorrhoeae on isolation of this organism, antibiotic-free chocolate agar (CA), modified Thayer-Martin medium (MTM), and a vancomycin-free selective medium (VFSM) were compared in a sexually transmitted disease clinic. Among 326 cervical gonococcal infections detected in a comparison of CA with MTM, 92.0% were detected on CA, compared with 98.2% on MTM (P < 0.001). Similarly, among 306 cervical infections detected in a comparison of MTM and VFSM, 95.8% of infections were detected with VFSM, compared with 98.4% for MTM (P = 0.10). For 1,632 urethral infections in men, all three media were equivalent, with none detecting fewer than 98% of the infections. Compared with a single inoculation, dual inoculation of MTM increased the diagnostic yield by 1.5% for 206 urethral infections and 2.4% for 83 cervical infections. In our clinic population, MTM is superior to CA or VFSM for the diagnosis of genital gonococcal infections, especially in women. The increased yield that accrued from inoculation of both MTM and either of the other media was not sufficiently high to warrant routine use of this practice in our clinic.

The therapeutic efficacy of six 13-lactam and aminoglycoside antibiotics were compared in diabetic mice with experimentally induced Klebsiella pneumoniae pneumonia. Lactams