Avaliação do uso de anti-sépticos bucais para redução da taxa de contaminação de culturas de micobactérias em amostras de escarro de pacientes com suspeita de tuberculose

Abstract

Identifying individuals with respiratory symptoms is considered an important strategy in detecting new cases of tuberculosis (TB). Although clinical and radiographic findings play an important role in the diagnosis of TB, a positive culture of Mycobacterium tuberculosis is a definitive diagnostic evidence of this disease. However, cultures can be contaminated with organisms from the oral microbiota that avoid the multiplication of the tubercle bacili and interfere in the diagnosis, especially in paucibacillary patients. Oral antiseptics have been used as a complement to oral hygienization in order to minimize proliferation of contaminant organisms. In the present study, we assessed the efficacy of intraoral anti-sepsis methods in the reduction of culture contamination. A hundred-twenty patients with respiratory symptoms were analyzed. On the first visiting day, a sputum sample was collected after the patient was oriented to do the oral hygienization using water (control group). On the next day, the same patient was selected at random to join one of two different groups before collecting the second sputum sample: 59 patients did oral hygienization using chlorhexidine gluconate (CHX) and 61 patients did oral hygienization using cetylpyridinium chloride (CPC). The use of different concentrations of PANTA antibiotic (1X e 2X) on MGIT medium was evaluated. The contamination rate found for the group of patients that used the antiseptic CHX was significatively lower than the one observed for the group of patients that used just water for oral hygienization, especially on MGIT cultures (p= 0,0391). The contamination rate was also significatively lower when samples were inoculated on MGIT medium supplemented with PANTA 2X (p=0, 0059). These results suggest that the use of CHX in oral hygienization is effective in reducing the contamination of mycobacteria culture with other organisms. In addition, the use of MGIT medium supplemented with PANTA 2X was also helpful in reducing the culture contamination rate.