| Congresso Brasileiro de Microbiologia 2023 | Resumo: 167-2 | ||||
Resumo:Stenotrophomonas maltophilia (S. maltophilia) is an environmental Gram-negative bacillus, intrinsically resistant to most antimicrobials. It is also associated to opportunistic infections in immunocompromised patients, such as those living with the human immunodeficiency virus (HIV), and the persistence in medical devices through the formation of biofilms. However, few is known about the presence and specific traits of this pathogen in the human oral cavity. The aims of the present study were to verify the presence and to characterize, by phenotypic and genotypic methods, S. maltophilia in saliva and gingival crevicular fluid (GCF) of HIV-positive individuals with periodontitis. A collection of saliva and GCF samples from 25 HIV-positive patients with periodontitis was tested by culture methods for the presence of S. maltophilia. Samples were collected in 2017 at the School of Dentistry of Ribeirão Preto (FORP/USP) from patients living in Ribeirão Preto and bordering cities. The project was approved by FORP/USP’s Ethical Committee and written informed consent was obtained from all patients (CAAE#: 50004415.1.0000.5419). Isolates were phenotypically characterized by the capacity to form biofilms in 96-well plates through a crystal violet staining assay. Phenotypic antimicrobial resistance was determined against ceftazidime and chloramphenicol using broth microdilution and minocycline, trimethoprim-sulfamethoxazole and levofloxacin using disk-diffusion. The genotypic relatedness of the isolates was determined by Enterobacterial Repetitive Intergenic Consensus - Polymerase Chain Reaction (ERIC-PCR) and Multi-Locus Sequence Typing (MLST). A total of five S. maltophilia strains were obtained, being three from GCF samples of three distinct patients, and two strains were isolated from saliva and CGF of a same patient. The five strains tested showed strong biofilm formation profiles. Resistance was noticed only against ceftazidime, a drug-of-choice for S. maltophilia infections, in all five strains tested. ERIC-PCR revealed an indistinguishable genetic profile, demonstrating a clonal relatedness among the five strains analyzed by this method. Moreover, all strains were assigned to ST88 by MLST. In conclusion, the presence of drug-resistant S. maltophilia in oral fluids of HIV-positive patients with periodontitis alert for its potential hazard for the development of opportunistic infections. In addition, the strong capacity to form biofilms and the clonality among strains from distinct individuals may reinforce the necessity of strict control of the presence of S. maltophilia in health environments and equipments with the aims to avoid the contamination of patients. Palavras-chave: Stenotrophomonas maltophilia, Periodontitis, Opportunistic infections, Biofilm, Antimicrobial resistance. Agência de fomento:CAPES, CNPq and FAPESP | |||||