Oral colonization of aerobic and facultatively anaerobic gram‐negative rods and cocci in irradiated, dentate, xerostomic individuals

Abstract

This study aimed at investigating the oral colonization of aerobic and facultatively anaerobic gram-negative rods and cocci in head- and neck-irradiated, dentate, xerostomic individuals. Subjects were recruited from a nasopharyngeal carcinoma clinic and were segregated into group A: <60 years (n=25, 48+/-6 years, 5+/-5 years post-irradiation) and group B: >or=60 years (n=8, 67+/-4 years, 2+/-2 years post-irradiation) and were compared with age- and sex-matched normal individuals, group C: <60 years (n=20, 44+/-12 years) and group D: >or=60 years (n=10, 70+/-3 years). Selective culture of the oral rinse samples was carried out to isolate, quantify and speciate (using API 20E kit) aerobic and facultatively anaerobic gram-negative rods and cocci recovery. All test subjects were put under comprehensive oral and preventive care for 3 months, and 12 group A and 5 group B subjects were recalled for reassessment of aerobic and facultatively anaerobic gram-negative rods and cocci colonization. All identical isolates, pre- and post-hygienic care, were phenotypically (Vitek, Hazelwood, MA and antibiogram profile) and genotypically (pulsed-field gel electrophoresis) evaluated. The aerobic and facultatively anaerobic gram-negative rods and cocci isolated from the first round oral rinse samples included: Acinetobacter, Neisseria, Chryseomonas, Flavimonas, Pseudomonas, Citrobacter, Enterobacter, Escherichia, Klebsiella, Flavobacterium and Weeksella species. The aerobic and facultatively anaerobic gram-negative rods and cocci isolation rate was high for irradiated individuals, and they were 64/25% and 100/80% for groups A/C and B/D, respectively. Recovery of aerobic and facultatively anaerobic gram-negative rods and cocci and Klebsiella pneumoniae subsp. pneumoniae in oral rinse samples were found to be significantly more prevalent in the irradiated subjects (groups A and B). Enterobacteriaceae were more frequently isolated from oral rinse samples of aged irradiated subjects (group B vs D, P<0.05), where the quantity of Citrobacter freundii (colony-forming units/ml oral rinse) was also significantly elevated. The isolation rate of aerobic and facultatively anaerobic gram-negative rods and cocci after hygienic care remained unchanged; 3 of 12 and 3 of 5 of the recalled subjects from groups A and B, respectively, harbored same aerobic and facultatively anaerobic gram-negative rods and cocci species. However, only two pairs of K. pneumoniae subsp. pneumoniae, sequentially isolated from same patients in group B, were found to be identical by pulsed-field gel electrophoresis. This may be due to reinfection of the microbes from the same source or permanent colonization. In conclusion, irradiation-induced xerostomia seems to favor frequent, repeated, transient intraoral colonization of aerobic and facultatively anaerobic gram-negative rods and cocci.

Isolation of a Fastidious Bergeyella Species Associated with Cellulitis after a Cat Bite and a Phylogenetic Comparison with Bergeyella zoohelcum Strains

“…It has also been linked to a leg abscess in a 10-year-old boy after a dog bite (20). Besides these reports, unidentified Weeksella species have been isolated from oral rinses of patients who were treated with radiation following nasopharyngeal carcinoma (15). A variety of food sources have been linked to Weeksella-and Bergeyellalike bacteria as well (1).…”

Microrganismos oportunistas e exógenos na microbiota bucal de pacientes oncológicos submetidos à radioterapia de cabeça e pescoço

“…Em pacientes submetidos a RT, a disfunção da glândula salivar leva à diminuição da produção de saliva, uma depuração reduzida de carboidratos e ácidos orgânicos, diminuição da capacidade tampão e remineralização dos dentes [4,5], além de alterar a microbiota oral [6]. Por conseguinte, a colonização e infecção oral por Candida spp.…”

“…Por conseguinte, a colonização e infecção oral por Candida spp. [1], microrganismos entéricos e outras bactérias patogênicas pode ser comum [6]. No entanto, a composição da microbiota oral em pacientes submetidos à radioterapia com CCP permanece obscura.…”

“…Susceptibilidade a mucosite está relacionado com alterações quantitativas e qualitativas na saliva, microbiota oral e estado imunológico [4,6].…”

“…Embora a colonização da cavidade oral por estes microrganismos oportunistas podem ser transitórios [6] …”