Banca de DEFESA: JOANNY RAYANE DA SILVA COUTINHO

Minimum inhibitory and bactericidal concentration of antimicrobials ciprofloxacin and ceftriaxone against bacterial isolates obtained from feces of cancer patients

intestinal microbiota; cancer; resistance; chemotherapy treatment; opportunistic bacteria.

The intestinal microbiota may undergo changes due to the damage caused by chemotherapy treatment, facilitating the dissemination of opportunistic multiresistant microorganisms resistant to antimicrobials during the treatment of cancer patients. In this context, the aim of this study was to evaluate the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the antimicrobials ciprofloxacin and ceftriaxone in bacterial isolates obtained from the stools of 30 cancer patients treated at a Reference Center in the state of Rio Grande do Norte and 10 healthy individuals called the control group. For this, all research participants answered a questionnaire about socioeconomic conditions, eating and hygiene habits and use of antibiotics and the samples obtained were sown on Nutrient Agar (AN), Macconkey Agar (MC) and Salmonella-Shigella Agar media. (SS) and performed the MIC and MBC of the antimicrobials ciprofloxacin and ceftriaxone considering the concentrations of 0.5μg/mL to 32μg/mL. The collected data were analyzed using chi-square test, ANOVA and Newman-Keusl test. Most patients declared themselves white (60%) female (93%), urban area residents (93%), had completed high school (30%) and most (50%) used the antibiotic amoxicillin before beginning of the study. The most frequent age group observed was between 46 and 65 years (53.3%) and 83.3% of the patients had breast cancer. Regarding the stage of cancer, 30% had cancer in stage III of the disease and 33.3% were unable to inform, with a higher symptomatological incidence of vomiting (88.7%), followed by diarrhea (66.7%) and nausea ( 50%). Considering MIC, ciprofloxacin drug resistance of 60% in AN medium and 56.7% in MC medium, with 73.3% drug susceptibility in SS medium. Regarding ceftriaxone, bacterial samples showed sensitive MIC (100%) in all media. With regard to CBM, 80% of the isolated samples were bactericidal, killing 99.9% of the bacteria exposed to the drugs ciprofloxacin and ceftriaxone, at concentrations of 8μg/mL and 4μg/mL, respectively. In the control group, the MIC was sensitive (100%) , confirming the change in the MIC of fecal bacterial samples from cancer patients. It is concluded that cancer patients undergoing chemotherapy are more likely to trigger an imbalance in the intestinal microbiota and increase the resistance of invasive microorganisms.