Number Of Gram-negative Rods Research Articles

A Case of Cutaneous Odontogenic Sinus

Despite the fact that cutaneous sinus tracts of odontogenic origin are well documented, the condition is still commonly misdiagnosed, because chronic periapical periodontitis may be asymptomatic and is rarely open to the skin. A 75-year-old Japanese woman presented to our clinic with the chief complaint of a left cheek skin lesion with mild pain. Physical examination revealed a subcutaneous nodule covered with erythematous skin on her left buccal region. Cultures from the subcutaneous nodule grew Bacteroides species and Peptostreptococcus micros but did not yield acid-fast bacilli, fungi, or Actinomyces. Stains of smeared pus showed a considerable number of Gram-negative rods. The histopathological examination revealed a focal abscess formation in the lower dermis and subcutaneous tissue. Dental evaluation, including an orthopantogram, showed a radiolucent alveolar area at the left lower first molar apex, suggesting a periapical abscess. Antibiotic therapy for three weeks associated with surgical root canal therapy eliminated the subcutaneous nodule. A high degree of suspicion is required to correctly diagnose a lower facial lesion as being of odontogenic origin, and prompt dental evaluation should be considered.

Salivary secretion rate, yeast cells, and oral candidiasis in patients with acute leukemia

Stimulated salivary secretion rate was repeatedly determined in 29 patients with acute leukemia during two periods of cytotoxic treatment in myelosuppressive doses. For comparison, the salivary secretion rate was studied in 83 healthy persons and in three other groups of hospitalized patients without malignant disorders. At the start of cytotoxic treatment the secretion rate in the patients with leukemia was lower than in healthy persons. The rate fell significantly after 1 to 3 days and later rose to the level seen in the healthy persons. Several interacting factors may have contributed to the decrease in salivary secretion rate, but the most important factor was probably the use of antiemetic drugs during the first 3 days of the study periods. No relationship was found between salivary secretion rate and the number of gram-negative rods found in the mouth. Patients with low salivary secretion rates had high numbers of yeast cells and more often oral candidiasis.

Zur bakteriologischen Charakterisierung der Gingivitis induzierenden Plaque bei unterschiedlichem Zuckergehalt der Nahrung

Abstract In a time period of 21 days an experimental gingivitis was induced in 8 volunteers. Four volunteers received a carbohydrate-reduced, the other 4 persons a carbohydrate-enriched diet. Clinical investigations on the development of plaque and gingivitis and bacteriological examinations of the supragingival microflora were performed simultaneously. The change in the composition of the supragingival plaque-microflora were nearly independent of the amount of food-carbohydrate. In the beginning of the experiment all volunteers had an almost pure streptococcal microflora but during the course of the experiment, the supragingival flora developed to a complex microflora with 50% anaerobes. The reduction of the number of streptococci was accompanied by an increase in the number of Gram-negative rods and actinomycetes. The development of gingivitis in persons with carbohydrate-enriched food was more rapid than in persons with carbohydrate-reduced food. It was striking that the occurence of clinical symptoms correlated with the increase of the number of Actinomyces viscosus in the plaque material.

Microbiological Studies Conducted in a Vertical Laminar Airflow Surgery

Quantitative and qualitative microbiological studies were conducted in a vertical laminar airflow surgery and in a conventional surgical theater. Samples were collected at floor levels within each surgery and also at the wound. Microorganisms recovered from the floor site were gram-positive cocci and gram-positive nonsporeforming rods, with considerably fewer numbers of gram-negative rods, Bacillus species, and molds. The predominant species recovered at the wound site were gram-postive cocci and gram-positive nonsporeforming rods. The level of airborne viable particles was higher in the conventional surgery than in the laminar airflow surgery, both within the room and at the incision. The same types and percentages of microorganisms found in samples collected at the floor level were found at the wound site in the conventional surgery.

Growth interactions of Arthrobacter globiformis and Pseudomonas sp. in relation to the rhizosphere effect.

Studies on the influence of plant roots on the soil microflora have shown that the number of Gram-negative rods in the rhizosphere is relatively higher than the number of Gram-positive rods, coccoid rods, and sporeforming types. This ecological phenomenon was duplicated and studied in a model system using a Pseudomonas sp. as representative of the rhizosphere and Arthrobacter globiformis as representative of the soil flora. Growth of A. globiformis was strongly suppressed in the presence of the pseudomonad in root extracts of mature plants and in a medium containing casamino acids, yeast extract, glucose, and mineral salts (CAYG medium); suppression was less marked in soil extract. The pseudomonad was unaffected in the association. A. globiformis was inhibited in the first 48-hour incubation in CAYG medium by acid elaborated by the pseudomonad; the pH dropped to 5.3 in 16 hours but rose steadily to alkaline conditions after 48 hours, resulting in a delayed increase in the number of A. globiformis to approximately that of a pure culture, in 5 days. Under cultural conditions favoring pigment production by the pseudomonad, growth of A. globiformis was completely inhibited throughout this period. Another toxic principle was also produced by the pseudomonad. This substance was biologically active in mixed culture against the Arthrobacter but was present in low concentration.