Selective medium for the isolation of Haemophilus aphrophilus from the human periodontium and other oral sites and the low proportion of the organism in the oral flora

We developed a medium for the selective recovery of Haemophilus aphrophilus. The medium, designated TSBVF, was composed of 4% tryptic soy agar, 10% heat-inactivated horse serum, 75 micrograms of bacitracin per ml, 5 micrograms of vancomycin per ml, and 50 micrograms of sodium fluoride per ml. TSBVF yielded a threefold higher recovery of oral H. aphrophilus than did chocolate agar with 75 micrograms of bacitracin per ml, which is a medium routinely used to diagnose human Haemophilus infections. H. aphrophilus and the few contaminating organisms on TSBVF were readily distinguished on the basis of colony morphology. The H. aphrophilus isolates exhibited variable fermentation of raffinose and dextrin but otherwise were biochemically similar. In a clinical study, H. aphrophilus was frequently recovered from supragingival plaque and saliva and occasionally from buccal mucosa and the tonsils. It was also isolated from 29 of 56 subgingival sites in 11 of 14 subjects. Its proportion of the subgingival microflora averaged 0.13% for healthy periodontal sites, 0.05% for adult periodontitis lesions, and 0.03% for localized juvenile periodontitis lesions. We concluded that H. aphrophilus is an indigenous bacterium of the human oral cavity. It occurs in low proportions in subgingival plaque and plays no apparent role in advanced periodontal disease in humans.

Evaluation of a non-radioactive DNA probe for detecting Porphyromonas gingivalis in subgingival specimens

This study compared the ability of a nonradioactive digoxigenin-labeled DNA probe and anaerobic culture to identify subgingival Porphyromonas gingivalis. Total cellular DNA from P. gingivalis ATCC 33277T was labeled using the Genius kit from Boehringer Mannheim Biochemicals. Anaerobic culture was performed using VMGA III transport medium and enriched brucella blood agar. The DNA probe could detect as little as 1000 P. gingivalis cells added to supragingival plaque. Also, the probe could detect P. gingivalis when it was present in proportions too low to be visualized on overgrown bacterial plates. The probe showed no visible reaction with strains of various oral species or with thousands of non-P. gingivalis colonies from plaque samples. VMGA III could maintain the viability of P. gingivalis for up to 6 days, as evidenced by DNA probing of colony blot of subgingival cultures. A total cellular DNA probe for detecting P. gingivalis seems to offer a simple and reliable method of detecting the organism in subgingival specimens.

Immunosuppressive effects of Prevotella intermedia on in vitro human lymphocyte activation

In this study, we have assessed four strains of Prevotella intermedia, isolated from periodontally involved lesions, for their ability to inhibit lymphocyte functions. All four strains were found to cause a dose-dependent inhibition of B- and T-cell proliferation in response to mitogens and antigens. This was reflected in altered DNA, RNA, and protein syntheses. Furthermore, P. intermedia appeared to affect the early stages of cell activation. This was ascertained by kinetic analysis in which it was determined that the extract had to be present during the first 24 h of incubation to cause suppression. Moreover, direct assessment of the early stages of cell activation indicated that release of cytokines and expression of the interleukin 2 receptor and CD69 on T cells were inhibited by P. intermedia sonic extracts. Finally, preliminary characterization of the immunosuppressive agent indicates that it has a molecular mass of approximately 50 kDa and is heat labile. It has been proposed that impaired host defense may play a pivotal role in the pathogenesis of many infections. The data presented in this paper suggest that microbially mediated immunosuppression may contribute to the pathogenesis of periodontal disease by altering the nature and consequences of host-parasite interactions.

Cytomegalovirus infection in symptomatic periapical pathosis

AIM

To compare the presence of human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) infections in samples from 25 symptomatic and 19 asymptomatic periapical lesions.

METHODOLOGY

Periapical samples were collected by sterile curettes in conjunction with apicectomy. cDNA-based HCMV and EBV identification was performed on total mRNAs extracted from peripapical tissues, using primers for genes transcribed during the productive phase of the herpesvirus infection. Statistical analysis was performed using chi-squared test.

RESULTS

HCMV was detected in 100% of the symptomatic and in 37% of the asymptomatic study lesions. EBV was identified only in HCMV-infected periapical lesions. The difference in occurrence of HCMV and EBV between symptomatic and asymptomatic periapical lesions was statistically significant (P < 0.0001).

CONCLUSIONS

The noteworthy finding of this study was the ubiquitous occurrence of HCMV active infection in symptomatic periapical pathosis. EBV may contribute to periapical pathogenesis in a subset of symptomatic lesions. HCMV and EBV infections may cause periapical pathosis by inducing cytokine and chemokine release from inflammatory or connective tissue cells, or by impairing local host defences resulting in heightened virulence of resident bacterial pathogens. Knowledge about the role of herpesviruses in periapical pathosis seems important to fully delineate the pathogenesis of endodontic infectious diseases. HCMV and probably EBV should be added to the list of putative pathogenic agents in symptomatic periapical disease.

Proficiencies of three anaerobic culture systems for recovering periodontal pathogenic bacteria

Anaerobic culture is employed routinely in the primary isolation of periodontal pathogenic bacteria. However, little or no data exist on the relative abilities of the Coy anaerobic chamber (Coy Laboratory Products, Grass Lake, Mich.), the GasPak (Becton Dickinson Microbiology Systems, Cockeysville, Md.), and the AnaeroPack (Mitsubishi Gas Chemical America, Inc., New York, N.Y.) systems to grow important periodontal species, including Porphyromonas gingivalis, Prevotella intermedia/nigrescens, Bacteroides forsythus, Eubacterium species, Campylobacter species, Fusobacterium species, and Peptostreptococcus micros. A total of 78 specimens from advanced periodontitis lesions were collected anaerobically, plated on enriched blood agar medium, and incubated at 35 degrees C for 5 to 7 days in each anaerobic culture system. The three culture systems were equally efficient in isolating Porphyromonas gingivalis and Prevotella intermedia/nigrescens. The Coy anaerobic chamber yielded the highest proportional recoveries of Campylobacter (P = 0.0001; nonparametric analysis of variance) and Eubacterium (P = 0.009). The Coy anaerobic chamber and the GasPak system demonstrated higher proportional recoveries of Bacteroides forsythus (P = 0.0006) and Peptostreptococcus micros (P = 0.0001) than the AnaeroPack system. The AnaeroPack system was most efficient in growing Fusobacterium species (P = 0.0001). Overall, the Coy anaerobic chamber and the GasPak system showed the highest proportional recoveries of putative periodontal pathogens, but the recoveries by the various anaerobic test systems varied considerably from sample to sample.

Periodontal microbiota of mobile and non-mobile teeth

The mechanism of accelerated periodontal destruction around teeth with occlusal trauma and increased mobility remains unclear. One possibility is that tooth mobility creates a subgingival environment conducive to overgrowth by periodontal pathogens. This study compared the subgingival microflora in mobile and non-mobile teeth of 35 adults on supportive maintenance therapy and 15 with untreated adult periodontitis. In each subject, subgingival paper-point samples were obtained from a mobile tooth with a probing depth of 4 mm or greater and from a non-mobile tooth with similar probing depth and gingival index. Samples were transported in VMGA III medium. Pockets around mobile teeth harbored significantly higher proportions of Campylobacter rectus (P = 0.001) and Peptostreptococcus micros (P = 0.05) than pockets with non-mobile teeth. Mobile teeth also tended to show elevated levels of Porphyromonas gingivalis, but this did not reach statistical significance. This study suggests that tooth mobility may constitute a risk for periodontal breakdown due to an increased subgingival occurrence of specific periodontopathogens. This hypothesis needs to be verified in longitudinal clinical and microbiological studies.

Primer for antimicrobial periodontal therapy

Successful prevention and treatment of periodontitis is contingent upon effective control of the periodontopathic microbiota. Periodontal pathogens reside in subgingival sites but also colonize supragingival plaque, tongue dorsum and other oral sites. Controlling destructive periodontal disease warrants a comprehensive antimicrobial approach that targets periodontal pathogens in various ecological niches of the oral cavity. Also, to effectively combat periodontal pathogens, the various elements of antimicrobial periodontal therapy should be engaged within a short period of time. Scaling and root planing, with or without periodontal surgery, along with proper oral hygiene, constitute the primary approach to controlling periodontopathogens. Antimicrobial agents administered systemically or locally can help suppress periodontal pathogens in periodontal sites and in the entire mouth. Microbiological testing aids the clinician in selecting the most effective antimicrobial agent or combination of agents, and in monitoring the effectiveness of periodontal treatment. The present paper considers theoretical and practical aspects of effective antimicrobial treatment of destructive periodontal disease.

Periodontal disease and dental caries in relation to primary IgG subclass and other humoral immunodeficiencies

22 females and 3 males with primary hypogammaglobulinaemia (n = 6) or IgG subclass deficiencies with (n = 3) or without (n = 16) concomitant IgA deficiency were examined for periodontal disease and dental caries. Only 1 patient showed more tooth loss than that found in the normal Swedish population. 1 patient demonstrated advanced periodontal disease. No patient exhibited more severe dental caries than that of comparable normal Swedes. Microbiological samples from periodontal pockets and saliva showed recovery of potential periodontopathic and cariogenic bacteria within normal ranges. This study could not support the notion that immunodeficient subjects exhibit an increased risk of developing periodontal disease or dental caries.

Clinical and microbiological characteristics of treated periodontitis patients on maintenance care

A population of 98 adults previously treated for moderate to advanced adult periodontitis and currently maintained in a recall program for at least one year were recruited for this study. The ultimate purpose of the study is to determine whether the presence of Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, and Bacteroides intermedius in selected periodontal sites can predict the future clinical course of these patients, particularly with respect to disease recurrence. This report presents the clinical design of the study which allows comparisons between sites positive and negative for these species in infected patients, and between sites in infected patients and comparable sites in non-infected patients. In addition, some base line clinical and microbiological data for these patients are presented. The distribution of PII and GI scores tended to be highest for molars, with the remaining teeth having similar scores. Probing depth measurements were greater for mesio-distal than oro-vestibular recordings. A bilaterally symmetrical pattern of increasing probing depth was noted from the midline distally on mesio-distal as well as oro-vestibular surfaces. Sites positive for the target organisms listed above tended to have greater probing depths (mean: 4.14 +/- 0.1 mm) than non-infected sites in the same patients (mean: 3.76 +/- 0.1 mm) or comparable sites in non-infected patients (mean: 3.54 +/- 0.1 mm).

Immunomodulatory effects of Bacteroides products on in vitro human lymphocyte functions

Bacteroides spp. have been implicated in the pathogenesis of several diseases, including periodontal diseases. In this study sonic extracts of 6 Bacteroides spp. were examined for their abilities to alter human lymphocyte function. We found that soluble extracts from Bacteroides intermedius, Bacteroides endodontalis, Bacteroides asaccharolyticus, Bacteroides melaninogenicus, and to a lesser degree Bacteroides loescheii, caused dose-dependent inhibition of human lymphocyte responsiveness to both mitogens and antigens. Suppression involved altered DNA, RNA and protein synthesis as well as immunoglobulin production. In contrast, Bacteroides gingivalis did not suppress these responses; instead, it stimulated lymphocyte proliferation and enhanced immunoglobulin production. It has been proposed that impaired host defense may play a pivotal role in the pathogenesis of many infections. The data presented in this paper suggest that microbial mediated immunosuppression may conceivably alter the nature and consequences of host-parasite interactions in periodontal disease.

Probe-specific DNA fingerprinting applied to the epidemiology of localized juvenile periodontitis

Although Actinobacillus actinomycetemcomitans has been recognized as a primary etiological agent in localized juvenile periodontitis, questions remain concerning the source of infection, mode of transmission, and relative virulence of strains. DNA fingerprinting analysis, using a randomly cloned chromosomal DNA fragment as a probe, revealed that previously characterized strains of A. actinomycetemcomitans displayed significant restriction site heterogeneity which could be applied to the typing of clinical isolates of this bacterium such that individual strains or variants could be traced within subjects from localized juvenile periodontitis families. Hybridization data derived from an analysis of bacterial isolates obtained from families participating in an ongoing longitudinal study of the disease showed that a single individual could be infected with more than one strain or variant of A. actinomycetemcomitans and that various members of the same family could harbor different strains or variants of the bacterium. In several cases the clinical isolates were matched to characterized laboratory strains by comparing hybridization patterns generated by digestion of the DNA with several restriction enzymes in independent reactions. Thus, probe-specific DNA fingerprinting of A. actinomycetemcomitans will permit us to determine if particular strains or variants are frequently associated with sites of periodontal destruction. Attention could then be focused on determining the virulence properties of those strains or variants that have in vivo significance.

Cellular fatty acid and soluble protein composition of Actinobacillus actinomycetemcomitans and related organisms

The cellular fatty acid and protein content of twenty-five representative strains of Actinobacillus actinomycetecomitans isolated from juvenile and adult periodontitis patients was compared to that of 15 reference strains of oral and nonoral Actinobacillus species and Haemophilus aphrophilus. Trimethylsilyl derivatives of the fatty acid methyl esters were analyzed by gas-liquid chromatography. The predominant fatty acids of all 40 strains examined were 14:0, 3-OH 14:0, 16 delta, and 16:0. Actinobacillus seminis (ATCC 15768) was unlike the other strains examined because of a greater amount of 14:0 detected. The soluble protein analysis using polyacrylamide gel electrophoresis revealed that A. actinomycetemcomitans, H. aphrophilus, and nonoral Actinobacillus species possessed distinct protein profiles attesting to the validity of separating these organisms into different species. Established biotypes of A. actinomycetemcomitans could not be differentiated on the basis of fatty acid or protein profiles.

Relationships among the oral fusobacteria assessed by DNA-DNA hybridization

DNA was purified from 16 strains of Fusobacterium nucleatum and from five strains representing other Fusobacterium species. The relationships among fusobacteria were examined by DNA-DNA hybridization and by determining the guanine plus cytosine content of the DNA. F. nucleatum was found to comprise a heterogenous group of organisms related to Fusobacterium periodonticum and Fusobacterium simiae, but unrelated to any of the other species of Fusobacterium tested.

Aggressive periodontitis associated with Fanconi's anemia. A case report

BACKGROUND

Fanconi's anemia is an autosomal recessive disease associated with chromosomal breakage as well as pancytopenia, skin pigmentation, renal hypoplasia, cardiac defects, microcephaly, congenital malformations of the skeleton, hypogonadism, and increased risk of leukemia. The present report describes the periodontal clinical and microbiological status of an 11-year old male having Fanconi's anemia.

METHODS

Polymerase chain reaction analysis to detect human cytomegalovirus (HCMV), Epstein-Barr type 1 virus, and herpes simplex virus (HSV) was performed on paper-point samples pooled from either 3 periodontal sites with advanced attachment loss or 3 gingivitis sites with no clinical attachment loss. Anaerobic bacterial culture examination was performed on the pooled periodontitis sample.

RESULTS

The patient suffered from pancytopenia, allergy, asthma, hearing impairment, and mental retardation. Dentition consisted of 7 primary teeth, 11 erupted permanent teeth, and 14 unerupted permanent teeth. Most erupted teeth showed severe gingival inflammation with some gingival overgrowth and various degrees of periodontal attachment loss. Genomes of HCMV and HSV were detected in the pooled periodontitis sample and HCMV in the pooled gingivitis sample. The periodontitis sample but not the gingivitis sample revealed HCMV mRNA of major capsid protein, suggestive of active viral infection. The periodontitis sample also yielded Actinobacillus actinomycetemcomitans (1.1% of total isolates), FusobActerium species (7.9%), Campylobacter species (2.2%), Peptostreptococcus micros (3.4%), and Candida albicans (0.3%).

CONCLUSIONS

Oral features of Fanconi's anemia may include increased susceptibility to periodontitis. It is likely that underlying host defense impairment coupled with periodontal infection by HCMV and A. actinomycetemcomitans contribute to the severe type of periodontitis associated with Fanconi's anemia.

Immune response to Fusobacterium nucleatum, Prevotella intermedia and other anaerobes in children with acute tonsillitis

The number of aerobic and anaerobic bacteria was determined in the saliva of 20 children with acute group A beta-haemolytic streptococcal (GABHS) pharyngo-tonsillitis, and 20 with acute non-GABHS tonsillitis. Antibody titres to four Gram-negative anaerobic bacilli that reside in the oropharynx (Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas gingivalis, and Actinobacillus actinomycetemcomitans) were determined in these and 20 control patients. An average of 8.8 aerobic and anaerobic isolates per patient saliva specimens were found during the acute tonsillitis stage in both groups, and 6.9 (in GABHS tonsillitis) and 5.6 (in non-GABHS tonsillitis) 5-6 weeks later. There were 10- to 1000-fold more bacteria in the acute stages of the inflammation in both GABHS and non-GABHS groups. These bacteria were Staphylococcus aureus, Haemophilus influenzae, Moraxella catarrhalis, Peptostreptococcus spp., F. nucleatum, Prevotella spp. and Porphyromonas spp. Significantly higher antibodies levels to F. nucleatum and P. intermedia were found in the second serum sample of patients with non-GABHS pharyngo-tonsillitis (P < 0.001) and GABHS tonsillitis (P < 0.05), as compared with their first sample or the levels of antibodies in controls. The increase in the number of several aerobic and anaerobic bacteria during acute tonsillitis and the increase in antibody levels to F. nucleatum and P. intermedia, known oral pathogens, may suggest a possible pathogenic role for these organisms in acute non-GABHS and GABHS tonsillitis.

Phenotypic and genotypic characterization of oral yeasts from Finland and the United States

A total of 4-22 isolates of oral yeasts per subjects from 48 yeast-positive Finnish and American subjects (25 females and 23 males) were phenotyped and genotyped to determine the frequency of simultaneous oral carriage of multiple yeast taxa. An oral sample from either periodontal pockets, oral mucosa or saliva was obtained. All subjects yielded Candida albicans and 3 subjects an additional yeast species (Candida krusei, Candida glabrata or Saccharomyces cerevisiae). The API 20C Aux kit distinguished 9 different carbohydrate assimilation profiles among the C. albicans isolates. Thirty-eight of 46 C. albicans biotype I isolates were categorized in a single numerical profile. PCR analysis, using a random primer OPA-03 and a repetitive primer (GACA)4, detected 2 major genotypic groups among the C. albicans isolates; 44 subjects showing isolates with a "typical" PCR-profile and 4 subjects isolates with an "atypical" PCR-profile. The "atypical" PCR-profile was similar to that of Candida dubliniensis. All C. albicans isolates assimilated xylose, except 5, including the 4 with an "atypical" PCR-profile. No difference was found in distribution of oral yeast species, and of C. albicans phenotypes and genotypes between Finnish and American subjects. The present PCR method may offer a rapid and easy means of distinguishing oral Candida species.

Human cytomegalovirus, Epstein-Barr virus and bone resorption-inducing cytokines in periapical lesions of deciduous teeth

BACKGROUND

A connection of herpesvirus periapical infection with symptomatic and large-size periapical lesions has been recognized in adult patients, but no data exist about a possible involvement of herpesviruses in severe periapical pathosis in children. Herpesviruses have the potential to elicit potent bone resorption-inducing cytokines in mammalian cells.

AIM

This study aimed to determine the occurrence of human cytomegalovirus and Epstein-Barr virus DNA, and mRNA transcripts of receptor activator of nuclear kappa B ligand (RANKL), osteoprotegerin, core binding factor alpha-1, colony stimulating factor-1, transforming growth factor-beta, and monocyte chemoattractant protein-1 in periapical symptomatic pathosis of deciduous teeth.

MATERIAL AND METHODS

Twelve deciduous molar teeth from patients aged 2-8 years were extracted due to severe periapical infection, and granulomatous tissue adherent to the root tip of the extracted teeth was collected using a surgical knife. Non-diseased pulpal tissue, obtained from 12 teeth extracted for orthodontic reasons, served as negative control. Polymerase chain reaction assays were employed to identify herpesvirus DNA and cytokine gene expression, using established polymerase chain reaction primers and procedures.

RESULTS

Seven (58%) of the periapical lesions yielded human cytomegalovirus and eight (67%) Epstein-Barr virus. Only one (8%) periapical lesion showed neither human cytomegalovirus nor Epstein-Barr virus. In healthy pulpal tissue, one (8%) specimen demonstrated human cytomegalovirus and another (8%) specimen revealed Epstein-Barr virus. Of the cytokines examined, RANKL expression showed significantly higher occurrence in periapical pathosis than in healthy pulpal tissue (P < 0.040). No relationship was identified between the type of herpesvirus and cytokine expression in the periapical lesions studied.

CONCLUSIONS

The present findings provide evidence of a putative role of human cytomegalovirus and Epstein-Barr virus in the pathogenesis of symptomatic periapical pathosis in deciduous teeth. Increased RANKL expression in periapical lesions may be of pathogenetic significance.

Experimental infections by Bacteroides gingivalis in non-immunized and immunized rabbits

The interactions between Bacteroides gingivalis and systemic antibodies were studied in tissue cages implanted in the backs of New Zealand white rabbits. Infectivity was evaluated according to clinical signs and to leukocyte and bacterial counts in material aspirated from the tissue cages. Pre- and post-inoculation antibody levels to sonicated whole bacterial cells were determined by enzyme-linked immunosorbent and agar immunodiffusion assays. Rabbits immunized against B. gingivalis and then challenged with pure cultures of B. gingivalis revealed complete elimination or markedly lower postinoculation bacterial counts and considerably weaker tissue reactions than non-immunized animals. B. gingivalis co-inoculated with Actinobacillus actinomycetemcomitans caused significantly more severe infections than observed in monoinfected animals. The present results suggest that the immune system acting through systemic antibodies and/or cellular mechanisms may modulate the pathogenic potential of infecting periodontal pathogens.

Immune response to Prevotella intermedia in patients with recurrent nonstreptococcal tonsillitis

The role of three oral flora organisms (Prevotella intermedia, Porphyromonas gingivalis, and Actinobacillus actinomycetemcomitans) was investigated in 31 children with recurrent nonstreptococcal tonsillitis. Antibody titers to the three organisms were measured by enzyme-linked immunosorbent assay in the 31 patients, as well as in 32 control patients who had not suffered from recurrent tonsillitis. None of the individuals in either group suffered from periodontal or dental illness. Significantly higher antibody levels to P intermedia were found in the study group as compared to controls (median 91.0 versus 72.5; p = .02). In contrast, the antibody titers to the other two organisms were generally low (less than 0.30), and no difference was found among the two study groups. The elevated antibody levels to P intermedia, a known oral pathogen that is also isolated from most recurrently inflamed tonsils, suggest a pathogenic role for this organism in recurrent tonsillitis.

Cellular fatty acid and soluble protein profiles of oral fusobacteria

We compared the cellular fatty acid and protein content of 43 strains of oral fusobacteria isolated from patients with chronic gingivitis, acute necrotizing ulcerative gingivitis, and juvenile and adult periodontitis, as well as from the stump-tailed macaque, to that of eight reference strains of oral and non-oral Fusobacterium species. A gas-liquid chromatographic examination of trimethylsilyl derivatives of the fatty acid methyl esters revealed n14:0, 3-OH-14:0, n16:0, 16:1, 3-OH-16:0, n18:0, and 18:1 in each of the 51 study strains, and a variable occurrence of 14 other fatty acids. The n16:0 to 3-OH-16:0 ratio distinguished between Fusobacterium nucleatum and the non-oral species Fusobacterium varium, Fusobacterium necrophorum, Fusobacterium russii, Fusobacterium necrogenes, Fusobacterium mortiferum, and Fusobacterium naviforme. The soluble protein content, as determined by polyacrylamide gel electrophoresis, varied considerably among the oral fusobacterial strains studied, and underscored the heterogenous nature of these organisms. "Fingerprinting" of oral fusobacteria may be readily accomplished by polypeptide analysis.

Evaluation of Fluoretec-M for detection of oral strains of Bacteroides asaccharolyticus and Bacteroides melaninogenicus

Fluoretec-M is a polyvalent conjugate used in direct fluorescent-antibody staining for identification of the Bacteroides asaccharolyticus-Bacteroides melaninogenicus group. The Fluoretec-M reagent detected all oral and nonoral test strains of B. melaninogaenicus subsp. intermedius, all test strains of B. melaninogenicus subsp. melaninogenicus, and the nonoral strains of B. asaccharolyticus. However, the Fluoretec-M polyvalent reagent and the monovalent conjugates which constitute Fluoretec-M did not detect the oral strains B. asaccharolyticus. The use of Fluoretec-M can therefore generate false-negative results in studies of specimens from oral cavity and from nonoral sites in which an infection with B. asacacharolyticus of oral origin may have taken place. It is suggested that antibodies reactive with the oral antigenic type of B. asaccharolyticus be included in the preparative procedure of the Fluoretec-M reagent.