In-vitro activity of spiramycin and metronidazole alone or in combination against clinical isolates from odontogenic abscesses.

One hundred and forty-eight isolates of bacteria from 20 intraoral odontogenic abscesses were tested for their susceptibility to spiramycin and metronidazole alone or in combination. All isolates, except Rothia spp. (one), Enterococcus avium (three), Haemophilus parainfluenzae (one) and Staphylococcus aureus (one) were sensitive to spiramycin and/or metronidazole. Among the anaerobes, spiramycin as well as metronidazole showed good antimicrobial activity against species of Prevotella, Eubacterium, Peptostreptococcus, Bacteroides and Porphyromonas. All the aerobes were resistant to metronidazole. A potential synergic effect was found in 17% of the clinical isolates tested, as the MICs of spiramycin and metronidazole for 25 isolates (21 isolates of Eubacterium, two of lactobacilli, one strain of Peptostreptococcus sp. and one Clostridium clostridiiforme) were significantly reduced by the addition of the other antibiotic.

Nonfluorescent erythrasma of the vulva.

BACKGROUND: Erythrasma is an uncommon vulvar infection, best diagnosed by its fluorescence under the Wood lamp. This report shows that despite a negative Wood lamp examination, the diagnosis can be made histologically. CASE: A 42-year-old woman was referred to our clinic with a persistent candidal infection. Evaluation included a Wood lamp examination, wet mount, and potassium hydroxide test of the affected skin, all of which were negative. A biopsy of the area demonstrated rods and filamentous organisms in the keratotic layer consistent with a Corynebacterium minutissimum infection. The patient was diagnosed as having erythrasma, and she responded to oral erythromycin. CONCLUSION: Persistent vulvar diseases may be caused by erythrasma despite a negative Wood lamp examination. The diagnosis can be made by biopsy of the lesion.

pH changes caused by bacterial growth in contaminated platelet concentrates.

While platelet concentrates are stored at room temperature, lactic and other acids are produced and the pH decreases as the buffering capacity of the plasma is exhausted. Platelet viability will be compromised if the pH decreases to pH 6.0 and below. Similarly, a pH decrease can be produced also by bacterial contamination if the organisms produce acid as an end product. Thus the determination of pH could serve as a sensitive indicator of bacterial contamination. This hypothesis was tested by us by inoculating known organisms into platelet concentrations. It was found that the pH may decrease, may remain unchanged, or, in a few cases, even increase. Visual signs of contamination could be observed but not consistently enough to be entirely dependable. Therefore, this method does not appear to detect bacterial contamination reliably in platelet concentrates.

Postoperative neurosurgical infections due to bacillus species.

The cases of 2 patients with postoperative ventriculitis due to Bacillus species bacteria are presented. Bacillus licheniformis was isolated from one patient following removal of an intraventricular meningioma, and Bacillus cereus from another patient following placement of a ventriculoperitoneal shunt. Both isolates were resistant to a variety of antibiotics, but both were sensitive to gentamicin and chloramphenicol. These cases emphasize several points; (a) Bacillus species, usually thought to be nonpathogenic, may produce intracranial infections; (2) species identification is important for epidemiological purposes and for the selection of appropriate chemotherapeutic agents; and (3) in cases of suspected ventriculitis, chloramphenicol or gentamicin should be considered for Gram's staining revealing gram-positive bacilli. In addition, we recommend that when planning antibiotic prophylactic regimens, consideration should be given to including one of these agents to assure coverage of Bacillus species.

Wound botulism in pediatrics.

A 6-year-old boy with congenital deafness sustained compound fractures to his left ulna and radius. Six days after the injury, he appeared lethargic, and his illness progressed to respiratory failure within three days. Although the wound at the fracture site appeared benign, cultures obtained when the wound was opened grew Clostridium botulinum, type B. Both the patient's deafness and the appearance of his wound contributed to the delay in diagnosis of wound botulism. Differential diagnosis and treatment of this rare entity are discussed.

Phaeohyphomycosis of brain: granulomatous encephalitis caused by Drechslera spicifera.

Drechslera spicifera is a dematiaceous fungus which occurs widely in nature but only rarely has been implicated in animal and human infections. Previous infections have occurred in superficial and subcutaneous sites or were encountered in immunologically compromised hosts. This report documents a case of granulomatous encephalitis due to Drechslera spicifera in an immunologically competent woman with no known underlying disease, from whom the fungus was isolated. Animal pathogenicity studies in mice reproduced the histopathologic features, and the fungus was reisolated from the animals.

Cerebritis due to group B streptococcus.

A premature infant who died of early-onset group B streptococcal meningitis was found to have cerebritis with direct bacterial infection of the basal ganglia. Although the organism was sensitive to penicillin by in vitro testing, it was not eradicated from the cerebrospinal fluid after 48 h of antibiotic treatment. These findings illustrate that suppurative extension with cerebritis of the basal ganglia as a complication of group B streptococcal meningitis may be one of the factors responsible for treatment failure.

Relative importance of bacteremia and viremia in the course of acute fevers of unknown origin in outpatient children.

During a 12-month period 80 children greater than 3 months of age seen at an emergency room with acute fevers greater than or equal to 39.7 C (103.5 F) and no localizing signs of infection were studied using blood and buffy coat cultures to isolate bacteria and viruses. Bacteremia was identified in three children (3.8%): two with Streptococcus pneumoniae and one with Neisseria meningitidis. Two children with viremia were identified: both isolates were ECHO virus, types 11 and 21, respectively. Fifty-eight of the study children (72%) were seen again in 24 to 48 hours and 27/58 (46%) were afebrile and completely well. No differences in sex, age, or initial WBC count existed among these children who returned afebrile and well and those with either localized disease or those persistently febrile.

Importance of medium in demonstrating penicillin tolerance by group B streptococci.

A total of 30 clinical isolates of group B streptococci were studied for penicillin tolerance in vitro. Minimal inhibitory and bactericidal concentrations of penicillin were determined simultaneously in three test media which have been used for group B streptococci, tryptose phosphate, Mueller-Hinton, and Todd-Hewitt broths, using a logarithmic-phase inoculum of 10(5) colony-forming units per ml. Minimal inhibitory concentrations in the three media did not differ significantly. However, minimal bactericidal concentrations were significantly higher in tryptose phosphate broth (mean, 1.04 mug/ml) than in Mueller-Hinton broth (0.22 mug/ml) or Todd-Hewitt broth (0.15 mug/ml). Similarly, ratios of minimal bactericidal to minimal inhibitory concentrations were significantly greater in tryptose phosphate broth than in Mueller-Hinton or Todd-Hewitt broth. After incubation in tryptose phosphate broth for an additional 24 h, the minimal bactericidal concentration consistently fell to levels which were only twice or equal to the minimal inhibitory concentration. This study illustrates the importance of the medium in the demonstration of penicillin tolerance and of controlling laboratory variables in the susceptibility testing of group B streptococci with penicillin.

Susceptibility of Acinetobacter calcoaceticus var. anitratus (Herellea vaginicola) to minocycline.

The in vitro activity of minocycline against Acinetobacter calcoaceticus var. anitratus (Herellea vaginicola) was examined. All strains of A. anitratus were inhibited by minocycline at concentrations of 0.4 mug/ml or less. The strains studied were considerably more susceptible to minocycline than tetracycline. No difference between the susceptibility to minocycline and tetracycline was seen with Escherichia coli, Klebsiella pneumoniae, Enterobacter and Proteus sp. A regression line of the log minimal inhibitory concentration (MIC) values and the diameter of the zone of inhibition, determined by the Kirby-Bauer technique, showed good linear correlation for minocycline. Comparison of the disk diffusion results and MICs indicated that an inhibitory zone size of 19 mm produced by a 30-mug minocycline disk was equivalent to a MIC of 3.1 mug/ml, a serum concentration achieved by oral administration of the drug. When the zone of inhibition was greater than 19 mm, however, there was poor correlation with the MIC for Enterobacteriaceae.