Ninety intestinal organisms (71 isolates from fecal samples of neutropenic patients with cancer or from various sites in patients with intraabdominal infections and 19 control strains) were examined by reverse-phase thin-layer chromatography for their ability to produce menaquinones in vitro. Menaquinones were found in all of 24 organisms of the Bacteroides fragilis group. Two other Bacteroides species, Bacteroides disiens and Bacteroides bivius, also produced menaquinones. A single isolate of Bacteroides species lacked menaquinones. These constituents were found in all of five strains of Escherichia coli, all of four strains of Klebsiella pneumoniae, five of eight strains of Propionibacterium species, two of five strains of Eubacterium species, and the one strain each of Arachnia propionica and Veillonella parvula tested. No menaquinones were detected in organisms of the genera Fusobacterium, Clostridium, Bifidobacterium, Lactobacillus, Actinomyces, Peptococcus, or Peptostreptococcus. These findings suggest that E. coli, Bacteroides species, and some gram-positive, anaerobic, non-spore-forming bacilli produce menaquinones that may be a source of vitamin K in patients who are deprived of exogenous vitamin K1.

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The minimum inhibitory concentrations (MICs) of azithromycin, erythromycin, ciprofloxacin and norfloxacin for 300 strains of Neisseria gonorrhoeae, 100 strains of Haemophilus ducreyi and six strains of Chlamydia trachomatis were determined. The two quinolones were more active against gonococcal strains than were the two macrolides. Azithromycin was approximately eight-fold more active against N. gonorrhoeae than was erythromycin (MIC90: 0.25 mg/l azithromycin, 2.0 mg/l erythromycin). The Mtr phenotype of gonococci increased azithromycin MICs approximately four fold. Azithromycin was less active than erythromycin against C. trachomatis. Azithromycin had considerable activity against H. ducreyi and was ten-fold more active than was erythromycin (MIC90: 0.004 mg/l azithromycin, 0.03 mg/l erythromycin). Clinical trials of azithromycin in the treatment of chlamydial infection and genital ulcer disease are indicated.

Serial, twice-weekly prothrombin times were determined in 108 febrile, granulocytopenic patients with cancer who were prospectively randomized to receive empiric antimicrobial therapy with moxalactam plus ticarcillin (M/T) or tobramycin plus ticarcillin (T/T). Thirty of 54 patients given M/T and 13 of 54 patients given T/T developed prothrombin times that were greater than or equal to 2 sec beyond control values (P less than .001) after a mean of 6.5 days of antimicrobial therapy. Serious bleeding episodes were more frequent in the group given M/T than in that given T/T (10 and two patients, respectively; P less than or equal to .05). Serial quantitative stool cultures revealed that both Escherichia coli and Bacteroides species were suppressed by greater than or equal to 5 log10 in eight of nine patients given M/T and in three of nine given T/T (P less than .05, Fisher's exact test). A significant reduction of the population of E. coli and Bacteroides fragilis, organisms that are major producers of bacterially synthesized menaquinones, was associated with a high incidence of hypoprothrombinemia. These observations support the hypothesis that menaquinones may play an important physiological role in the maintenance of blood coagulation during episodic dietary deficiency of phylloquinone.