title: Techniques for controlling variability in gram staining of obligate anaerobes.
abstract: Identification of anaerobes recovered from clinical samples is complicated by the fact that certain gram-positive anaerobes routinely stain gram negative; Peptostreptococcus asaccharolyticus, Eubacterium plautii, Clostridium ramosum, Clostridium symbiosum, and Clostridium clostridiiforme are among the nonconformists with regard to conventional Gram-staining procedures. Accurate Gram staining of American Type Culture Collection strains of these anaerobic bacteria is possible by implementing fixing and staining techniques within a gloveless anaerobic chamber. Under anaerobic conditions, gram-positive staining occurred in all test organisms with "quick" fixing techniques with both absolute methanol and formalin. The results support the hypothesis that, when anaerobic bacteria are exposed to oxygen, a breakdown of the physical integrity of the cell wall occurs, introducing Gram stain variability in gram-positive anaerobes.
authors.affiliation: Department of Biology, Sonoma State University, Rohnert Park, California 94928, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Johnson
authors.forename: E
authors.initials: E
authors.lastname: Thatcher
authors.forename: M E
authors.initials: ME
authors.lastname: Cox
mesh_terms: D001421:Bacteria, Anaerobic / Q000302:isolation & purification; D005404:Fixatives; D005557:Formaldehyde; D005840:Gentian Violet; D006094:Gram-Positive Bacteria / Q000302:isolation & purification*; D000432:Methanol; D010619:Phenazines; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013194:Staining and Labeling / Q000379:methods*
chemical_list: D005404:Fixatives; C035863:Gram's stain; D010619:Phenazines; D005557:Formaldehyde; D005840:Gentian Violet; D000432:Methanol