Changes in oral aerobic microflora in patients under radiotherapy

ABSTRACT

Eleven normal controls and thirty patients with head and neck cancer, who received a full tumoricidal dose [6000 CGY] of cobalt 60, were chosen to study the effect of this ionizing irradiation upon the bacterial flora of those patients. For all studied subjects [diseased and normal] mid-morning samples of saliva were collected and cultured under aerobic conditions on blood agar and MacConkey's media. Samples were taken pre, mid and at the completion of irradiation from head and neck cancer patients. In this study, with radiotherapy for head and neck cancer patients, the main change in aerobic microbial organisms was noted in staphylococci, where there was a marked increase in percentage of cases with positive culture for staphylococcus aureus, marked decrease in percentage of cases with positive culture for staph. albus and complete absence of staph. citneus. The Gram-negative bacilli were absent and they appeared at the end of irradiation. From this study, it was found that the postoperative sepsis in previously irradiated patients is not only due to immunological depression which renders the patient more liable to infections, or only due to tissue devitalization but also due to well evident changes in the regional bacterial flora, which were related to the site of tumour and to the degree of oral exposure to irradiation