This prospective cohort study is first from Haryana, India and is based on evaluation of the rate, risk factors and outcomes of treatment procedures between oral cancer patients. The present report describes colonization of bacterial and fungal infectious pathogens in oral cancer patients.
The colonization of microorganisms in cancer patients was found to occur in oropharynx as well as gastrointestinal system, urinary system and airways. Colonization starts within 48 hours of hospitalization . Number of studies proved that Neutropenia increases the microbial colonization [39–41]. Our observation also illustrates that the colonization of microorganisms was higher in blood and oral cavity of neutropenic cases after chemotherapy, radio chemotherapy.
Nowadays, in most of hospitals, there is a shift of the microbial spectrum of cancer patients from gram-negative to gram positive, compared with the predominance of gram-negative species in the 1960s and 1970s [42–46]. Nevertheless in developing countries there is a different situation where the predominant pathogens are gram-negative, the reason maybe the people cannot afford to give routinely prophylactic oral antibiotics, such as quinolones, and use less central lines. The predominance of gram negative bacteria in developing countries can also be explained with the help of various studies. A study was conducted on febrile neutropenic patients in a hospital from Lebanon and observed that the gram-negative bacteria were responsible for 78.8% (26/33) of bloodstream infections compared to 33.3% (11/33) gram-positive organisms. In the present study dominant gram negative bacteria were of E. coli and P. aeruginosa. A possible explanation of the observed high incidence of gram-negative infections in Lebanon was the relatively low proportion of indwelling catheters . Another study was carried in Malaysia observed that out of 120 episodes, 60.02% were gram-negative organisms of Enterobacteriaceae . A similar pattern of predominant gram-negative bacteria (61%) was seen in a study of hematologic malignancy patients from Brazil . Similar to above study we have also observed that main pathogen isolated from blood of group I and oral cavity of group II were of gram negative bacteria. This may be due to absence of use of catheter as a routine practice during the period of our analysis.
In our study P. aeruginosa was the main gram negative bacteria in blood stream and K. pneumonia was in oral cavity. Similar to our study the presence of P. aeruginosa as an infectious pathogen was also observed by Raje et al., . They reported P. aeruginosa (28%) as a major pathogen in febrile neutropenic patients of acute lymphobalastic leukemia cases. Karim et al.,  and Saghie et al.,  were also observed presence of P. aeruginosa in 31% and 38% respectively from febrile neutropenic cases. However our study showed the proportion of P. aeruginosa was higher in non- neutropenic cases.
The present report also revealed the predominance of gram positive bacteria (S. aureus and S. epidermidis) in blood of group II, III and oral cavity of I, III group. The predominance of gram positive bacteria as infectious pathogen was also proved by other studies did in India. Jagarmuldi et al.,  conducted a study on acute leukemia cases and observed 38.5% of S. aureus infection in 240 febrile episodes and in other study S. aureus (39%) infection was observed in blood after chemotherapy . The prevalence of gram positive bacteria may be due to that oral cancer patient were undergone treatment of high intensive chemotherapy, radio chemotherapy which may be led to damage of the mucosal barriers and increases the risk of infection with gram-positive oral (and GI) flora . In favor of that reason, we observed the significant predisposing factor for blood stream infection was the use of central venous line (P < .05) in group III, which may be facilitated the entry of organisms colonizing the skin into the bloodstream, and thus increase the rate of Staphylococcal infections in blood and oral cavity [2, 43]. Our study also observed another significant predisposing factor of bloodstream infection in group III was nosocomial acquired (P < .01). The role of nosocomial acquisition of S. aureus infection was also demonstrated in various studies did at five centers in Egypt and a provincial hospital in north east Thailand [55, 56]. Nosocomial infection of S. aureus in developing countries is probably common, the reasons for which may include lack of hand washbasins or hand washing, overcrowding in hospital wards and clinics, lack of infection control training or policies, the inability to isolate specific patients, and lack of diagnostic microbiology facilities .
Another salient featured of our study was the colonization of C. albicans as most significant oral cavity pathogens in group I and III patients. C. albicans was isolated in group I neutropenic, non neutropenic cases in proportion of 45.90%, 48.78% respectively and in group III its proportion in neutropenic, non neutropenic cases was 28.2%, 27.72% respectively. The proportion of C. albicans in group I i.e. radiotherapy treated, cases was similar to various studies conducted on oral candidiasis after radiotherapy and showed a wide variation ranging from 17 to 52.5% [4, 17, 19, 57–60]. The colonization of C. albicans in oral cavity of radiotherapy treated, cases may be due to the reason that our patients were often unable to maintain satisfactory oral health and nutritional status during RT, mainly because of low income and educational level. This reasons of colonization of C. albicans in oral cavity was also observed in study did in Brazilian patients undergoing head and neck radiotherapy . The pathogenesis of candidal infections is complex encompassing both fungi and host factors. Candidal colonisaion appears to be influenced by adherence mechanisms among fungi and oral epithelial cells. Radiotherapy-induced hyposalvation also encourages oral candidal colonization that often leads to oral candidiasis .
We have also observed other reason of colonization of C. albicans may be oral mucositis, which played a significant role in oral cavity infection of all three groups. Generally it is also accepted that oral mucositis, is of multifactorial origin, and it is ranged among 20% and 100% in patients receiving different types of cancer treatments [61–65]. Other reason for the prevalence of mucositis in our study may be due to fluorinated 5-fluorouracil (5-FU) which was the most effective and frequently used antineoplastic agent for the treatment of oral cancer. There are others reports which also showed mucositis (4 to 74% for head and neck cancers) induced by 5-FU [66, 67].
Some limitations were present in our study, first was that we did not take the clinical features of Oral candidosis in our patients i.e. we were not able to evaluate that whether the Oral candiasis remain confined to the oral cavity, or spread to oesophageal or more widely to cause systemic candidosis. This study also is limited to infections caused by aspergillosis and candidiasis. Although these two pathogens represent most of fungal infections, infections due to other fungal species may result an additional burden to the oral cancer cases.