Glenn E. Minah

Microbiological studies of carious dentine from human teeth with irreversible pulpitis

Aerobic and anaerobic cultures were made from 29 extracted teeth with irreversible pulpitis to identify the predominant flora in different parts of deep carious lesions. Most isolates were Gram-positive rods, in which lactobacilli were the most frequent organisms, then other Gram-positive, non-branching rods. Gram-positive cocci were the next most common; only a low number of Streptococcus mutans was recovered. Two types of carious lesions were found, one with high numbers of lactobacilli, the other with low. In the 15 lesions with high numbers, lactobacilli constituted 91.9% of the total flora at the pulpal site and gradually decreased in number as the sampling moved away from the pulp. Strep. mutans and alpha-haemolytic streptococci were not recovered from pulpal or deep carious sites in this group. In the 14 lesions with low numbers of lactobacilli, the flora was diverse. Gram-positive cocci, anaerobic Gram-positive non-branching rods, branching rods and/or Bacteroides were the main isolates in a few of this group.

Microbiology of acute periodontal infection in myelosuppressed cancer patients.

This study characterized the subgingival microbial flora associated with 27 acute exacerbations of preexistent periodontal disease in 24 patients with chemotherapy-induced myelosuppression. All but two acute periodontal infections developed at low granulocyte levels (less than 1,000/microL). Suspected pathogens were detected in high concentrations in subgingival plaque specimens in 17 episodes of acute periodontal infection; a single pathogen was recovered in ten acute infections, and more than one pathogen was recovered in seven acute infections. Staphylococcus epidermidis, Candida albicans, S aureus, and Pseudomonas aeruginosa predominated, with combinations of these detected in some patients. Concomitant bacteremias developed in two of these patients. The subgingival microflora associated with ten acute periodontal infections was characterized by predominantly indigenous microorganisms, which in nine episodes were in abnormal proportions compared with microbial profiles in noncancer patients with similar degrees of periodontal disease. These data demonstrate that pathogens normally associated with infections in myelosuppressed cancer patients, as well as indigenous oral flora, are associated with acute periodontal infections during granulocytopenia. This finding is important, since this body site has not commonly been recognized as a source for acute infection in these patients.

Effect of granulocytopenia on oral microbial relationships in patients with acute leukemia

Risk for acute infection increases as granulocyte levels decrease secondary to myelosuppressive chemotherapy in patients with acute nonlymphocytic leukemia (ANLL). Acute exacerbations of concomitant inflammatory periodontal diseases can result in systemic infections in these patients. However, host-oral bacterial relationships in the periodontium in patients with ANLL are not well understood. Twenty-one adult patients with ANLL with periodontal disease ranging from gingivitis to severe periodontitis were studied. Supragingival and subgingival plaque specimens were collected before chemotherapy (prechemotherapy), and at a defined midpoint of myelosuppression (midchemotherapy; day 14). All specimens were extensively cultured both aerobically and anaerobically. Data were submitted to a partial correlational analysis, controlling for covariation relation to oral hygiene intervention and antibiotic administration. Levels of total yeast exhibited a significant association with Staphylococcus sp. at supragingival sites midchemotherapy (r = 0.68, p less than or equal to 0.05). Levels of total yeast also correlated positively with Pseudomonas aeruginosa at subgingival sites both prechemotherapy (r = 0.70, p less than or equal to 0.01) and midchemotherapy (r = 0.61, p less than or equal to 0.05). Significant correlations of levels of Veillonella sp. with Neisseria sp. and gram-negative enteric bacilli were observed in both supragingival (r = 0.95, 0.77, p values less than or equal to 0.01) and subgingival (r = 0.69, 0.61, p values less than or equal to 0.05) plaque specimens midchemotherapy but not prechemotherapy. These data suggest that potentially pathogenic bacteria occur in plaque simultaneous with granulocytopenia in these patients. Multiple mechanisms, including intergeneric coaggregation and other symbiotic relationships, may influence infectivity of the mixed plaque flora and thus contribute to the oral ecology observed in these patients.

The effect of a denture adhesive on the colonization of candida species in vivo

PURPOSE The purpose of this study was to evaluate the effect of a single denture adhesive on oral quantities of Candida species in vivo by determination of absolute and proportional counts of Candida species on dentures and in saliva of individuals who used this denture adhesive for a period of 14 days. MATERIALS AND METHODS Samples were collected from saliva and maxillary dentures of 12 patients who wore existing dentures without adhesives for 2 weeks, then wore dentures with adhesive (Poly Grip Free; Glaxo Smith Kline, U.K.) for 2 weeks. Periodically, maxillary dentures were sampled by adding saline to the intaglio surface, dispersing by sonication and removing aliquots for culturing. These aliquots and saliva were diluted and plated in duplicate on bismuth sulfite, glycerine, and glucose yeast agar (Biggy) for recovery of Candida and on trypticase soy agar for total viable counts (TVC) of the microbiota. After 72 hours of incubation at 37 degrees C in air with 10% CO(2), colony-forming units were enumerated. In each individual, absolute counts of Candida and TVC, and proportional counts of Candida relative to TVC were compared and statistically evaluated during the periods of no adhesive use (control) and adhesive use (test). RESULTS There were no statistically significant differences between the test and control periods for recovery of total Candida or TVC in saliva or on dentures, or the percent of Candida relative to TVC in saliva or on dentures. CONCLUSION Within the limitations of this study, the data suggested that the denture adhesive tested did not significantly alter the denture microbiota during the 14-day trial period.

Isolation of pathogenic microorganisms from dentures and denture-soaking containers of myelosuppressed cancer patients.

I nfection is the leading cause of morbidity and mortality in patients undergoing myelosuppressive cancer chemotherapy. ‘9 2 Bone marrow supp ression and mucosal damage sustained during chemotherapy predispose these patients to infection.‘s4 Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, other gram-negative bacilli, Staphylococcus aureus, and yeasts are responsible for the majority of infections in this population. 5-* Many of these pathogens are thought to be acquired or to ascend to predominance after admission to the hospital. 6,7 At the Baltimore Cancer Research Center (BCRC) during 1971-1976, surveillance cultures of 135 patients with acute nonlymphocytic leukemia (ANLL) demonstrated that new organisms were acquired at a rate of 0.5 organism per patient per week. Many of these organisms were gram-negative bacilli and species of yeast.’ Severely myelosuppressed patients appear to be especially susceptible to infections from these organisms.2~3~5~7 Infection in these patients can be exogenously or endogenously derived.’ Defined exogenous sources include food, water, bathtubs, shower stalls, ice machines, respirators, humidifiers, intravenous catheters, urinary catheters, and members of the hospital staff.8~‘o The primary endogeneous source is the patient’s alimentary canal.8 Dental prostheses and denture-soaking containers might represent a significant microbial reservoir for infection and cross-contamination but have not been evaluated. Investigations have shown that complete dentures from immunocompetent patients are capable of supporting the growth of microorganisms and can, therefore, serve as inadvertent transport mediums for potentially infectious organ

Correlation between thermal sensitivity and microorganisms isolated from deep carious dentin

The correlation between thermal sensitivity and the microorganisms present in 29 deep carious lesions was studied. The numbers of lactobacilli and total Gram-positive rods in the carious lesions were found to be negatively related to the length of pain triggered by cold and heat stimulants. The presence of Gram-positive cocci and non-black-pigmented Bacteroides were positively associated with both cold and heat sensitivities. Black-pigmented Bacteroides, Streptococcus mutans, and total anaerobic colony counts were positively related to the heat sensitivity. Recovery of Fusobacterium nucleatum, Actinomyces viscosus, and enterics on the selective plates was associated with cold sensitivity. Total counts of Gram-positive cocci and Gram-negative rods on the anaerobic nonselective medium were positively related to the cold sensitivity. It appeared that teeth with low numbers of lactobacilli in the carious lesions usually responded to thermal tests with longer duration of pain. Conversely, teeth with high numbers of lactobacilli in the carious lesions usually responded with shorter duration of pain.

Growth of potential pathogens in denture-soaking solution of myelosuppressed cancer patients

M yelosupprcssion that results in markedly decreased numbers of circulating granulocytes and mucosal damage sustained during antineoplastic chemotherapy may predispose cancer patients to infection.‘.’ The more profound the myelosuppression, the higher the risk of infection, with a significantly higher probability of infection when granulocyte levels fall to less than 1 OO/&‘~ * Most of the infections are caused by opportunistic gram-negative bacilli, especially Pseudomonas aeruginosa, and several species of fungi.“-” Many of the organisms, which are thought to be acquired nosocomially or succeed to predominance after admission to the hospital, effect a change in the patient’s normal flora.‘~‘~ I2 As the organisms are generally not present in the pharynx of a normal population, such factors as hospital treatment modalities, serious systemic disease, and debilitation are thought to select for these pathogens.‘3-‘S Most infections in this population result from microorganisms that have colonized the patient’s alimentary canal, including the oral cavity.‘0,‘P.20 Exogenous sources of infection include food, water, shower stalls, humidifiers, ice machines, respirators, intravenous catheters, and members of the hospital staff.” In one investigation, dentures and denture-soaking containers used by myelosuppressed hospital patients were found to be contaminated heavily with pathogens, especially gram-negative bacilli. 2’ Under these conditions dentures could serve as reservoirs for pathogens in the hospital environment and as a source of infection and cross-contamination. The objective of this investigation was to determine if denture-borne pathogens would

Comparative Microbiological and Immunological Studies of Subgingival Dental Plaque from Man and Baboons

Baboons may be useful as animal models for the study of human oral diseases and infections. They are closely related to man anatomically, physiologically, and phylogenetically. Plaque and gingival indices were relatively low in 18 baboons (Papio anubis). The mean scores ranged between 0.62 ± 0.29 and 0.37 ± 0.20, respectively. Gram-positive and Gram-negative cocci comprised 27.0 ± 32.4 and 3.1 ± 7.5% of the total viable counts in the dental plaque samples. Black-pigmented Bacteroides formed about 1.9 ± 5.9% of the bacterial population in the samples. Anaerobic Gram-negative bacilli were found in 73.2% of the samples and averaged 19.2 t 26.3% of the total recovered flora. Species of the oral Actinomyces and other Gram-positive rods found in humans were not isolated. The composition of the oral flora in baboons appeared to be significantly different from that of man. Isolates of F. nucleatum, L. buccalis, and B. intermedius from the two mammals were biochemically similar, but were distinguishable by analysis with antibody, both by precipitin lines and/or differences between homologous and heterologous titers.