Microbial Basis of Oral Malodor Development in Humans

Abstract

To better understand the microbial basis of oral malodor development in humans, we used a cross-sectional and longitudinal study design and the pyrosequencing approach to track and compare the tongue microbiota associated with oral malodor in 29 Chinese adults who underwent a consecutive three-day evaluation for the amount of H 2 S excreted orally. Three levels of the oral malodor state (healthy, oral malodor, and severe oral malodor) were defined based on the H 2 S level. Community structure of the tongue plaques was more sensitive to changes of malodor state than to interpersonal variations or differences in sampling times. Within each individual, the structure of microbiota was relatively stable, while their variations were correlated with the change in the H 2 S level. Severe oral malodor microbiota were the most conserved in community structure, whereas the healthy ones were relatively varied. Oralmalodor-associated bacteria were identified. The relative abundance of Leptotrichia and Prevotella was positively correlated with oral malodor severity, whereas Hemophilus and Gemella exhibited a negative relationship with oral malodor severity. Our study provides one of the first landscapes of oral microbiota changes associated with oral malodor development and reveals microbes potentially useful to the evaluation and control of oral malodor.

Leptotrichia species in human infections II

“…Since previous reviews [2,3], Leptotrichia species have been reported in >124 cases [4,7,16,18–69,87–93], whereby 30 cases involved L. buccalis [4,8,15,21,34,52,56,70–79,87], 24 cases L. wadei [4,20,24,34,37,42,48,56,67,80,81,90,93], 16 cases L. trevisanii [4,5,9,10,13,14,17,37,87], 14 cases L. hofstadii [34,40,49,56,81–84,93], 10 cases L. goodfellowii [4,11,12,21,56,74,85,87], eight cases L. hongkongensis [4,6,18,45,47,56], and five L. shahii [34,56,86]. L. trevisanii and L. wadei bacteremia are extremely rare; clinicians should consider these species in cases involving immunocompromised patients with oral lesions [4,5,13,17,87].…”

“…Saliva, plaque, and the oral mucosal surface of caries patients [34,37,56,67] and the oral cavity and biofilms from oral epithelial cells of a patient with new-onset rheumatoid arthritis [20,48] all contained L. wadei . Patient material from tongue plaque, saliva, and the tongue coating of malodor and halitosis patients [42,81] was isolated with L. wadei present. This bacterium was even isolated from the antral gastric biopsy of a dyspeptic patient [80], smokers’ plaque [90], and oropharyngeal samples (Table 2) [93].…”

“…Leptotrichia species were also isolated from bronchoalveolar lavage fluid, and patients with leukocytosis, hypoxemia, and dyspnea [24]. Further, Leptotrichia species were recovered from healthy patients with oral cancer, premalignant oral lesion [18,28,33,56,91], edentulous infants [29], human vaginal fluid of sexually active and inactive individuals [30,32], HIV-seropositive and -seronegative patients [46], pancreatic cancer patients [18,66], black pigmented stain caries patients [63], and patients with halitosis (Table 2) [42,65,81,82]. Besides, Leptotrichia species were isolated from the blood [4,5,22,74], the amniotic fluid of a patient with a wound and respiratory difficulties [4], breast milk of obese women with gestational diabetes and normal weight [36], oral samples of a patient with new-onset rheumatoid arthritis [20], oral lichen planus patients [88], and even from fermenting Lees liquor [39].…”

“…Also, Leptotrichia species were isolated from tumor tissues and sputum of patients with tuberculosis, acute exacerbation of chronic obstructive pulmonary disease, and feces of piglets with porcine epidemic diarrhea virus [40,41,43,50,51]. They were also detected in patient material from tongue plaque with malodor [42], biofilms of caries, oral epithelial cells [48,49], vaginal swabs with high-risk human papillomavirus, and from HIV-positive and -negative subjects [55]. The guts of herbivorous, carnivorous, and omnivorous fish [58], tumor tissues and saliva of patients with head and neck squamous-cell carcinoma human papillomavirus (HPV), oropharyngeal squamous-cell carcinoma HPV, and oral cavity squamous-cell carcinoma HPV [19] all contained Leptotrichia species.…”

“…L. trevisanii was involved in 15 incidences of bacteremia. Eight cases each also involved Leptotrichia species and L. buccalis , six L. goodfellowii , three L. wadei , two L. hongkongensis , and one with L. shahii (Table 2) [4–6,9–15,17,21,22,33,42,74,78,85–88]. In cases involving L. trevisanii , seven were also associated with neutropenic fever [5,13,14,17,87], while five were associated with PBSCT [9,10], four had acute myelogenous leukemia (AML) [5,7 9,10,15] and multiple myelomas (MM) [4,9,13], two had stomatitis [10,14], three had NHL [9,87], and one had a catheter-related bloodstream infection [17].…”