Introduction: Oral cancer is the third most prominent type of cancer in Bangladesh. During or after oral cancer treatment, immune-compromised cancer patients may be susceptible to an infection by multi-drug-resistant opportunistic microbes. This study aims to identify the prevalent microorganisms from the infected site of oral cancer patients and observe their antibiotic susceptibility pattern. Materials and Methods: Clinical samples were collected from the infected sites of oral cancer patients and healthy people. The swabs collected were placed on nutrient agar slant, then incubated for 24 hours at 37ºC. Bacteria from the slant were inoculated in several selective media (Mannitol Salt Agar Media, KF Streptococcus Agar media, Cetrimide Agar, Eosin Methylene Blue Agar). Several biochemical tests identified opportunistic microorganisms. Finally, the antibiotic susceptibility test was performed by the Kirby Bauer disc diffusion method. Results: The study found that 65.4% of microbes isolated from the patients’ oral cavities were Gram-negative bacteria, and 34.6% were Gram-positive bacteria. Among the patient group isolates (n = 55), the most prevalent organism was Pseudomonas spp. (30; 54.54%). Others were Klebsiella spp. (27; 49.09%), Staphylococcus spp. (24; 43.63%), E. coli (14; 25.45%), Streptococcus spp. (14; 25.45%), Proteus spp. (12; 21.8%) and Enterococcus spp. (6; 10.90%). Both Gram-positive and Gram-negative microbes from the patient group have shown high resistance to the commonly used antibiotics. In the control group (n = 50), the most prevalent organism was Staphylococcus spp. (15; 30%). Other organisms were Streptococcus spp. (6; 12%), Klebsiella spp. (11; 22%), E. coli (3; 6%), Streptococcus spp. (14; 25.45%), Pseudomonas spp. (8; 16%). The microbes of the control group showed less resistance to the antibiotics and rather showed sensitivity to them. Conclusion: The study revealed a high prevalence of multi-drug-resistant opportunistic microbes on immune-compromised oral cancer patients compared to microbes isolated from healthy people’s oral cavity.
Maintaining good oral health is an integral part of human health. However, at present, oral cancer is one of the most critical health issues. This cancer is the sixth most common cancer worldwide, and every year, half a million people are diagnosed with this type of cancer. It is prevalent in areas where betel quid chewing, smoking, and alcohol drinking are observed in high frequency. Forty percent of cancer cases in Southeast Asia refer to oral cancer [
In Bangladesh, the rate of oral cancer is high. A study revealed that cancer cases are approximately 200,000 per year and among them, oral cancer represents 20%, and it is the third leading cancer occurring in this country [
Despite significant development in oral cancer treatment, cancer patients remain at risk of developing severe infections. The immune-compromised patients are susceptible to infections by drug-resistant opportunistic microbes like Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella, E. coli. This infection may occur during the cancer progressions or after surgery [
For treating infected oral cancer patients, all kinds of antibiotics can be used. Many antibiotics are resistant to both gram-positive and gram-negative bacteria. Sometimes a mixture of antibiotics is used for better treatment. The antibiotics generally used are cephalosporins, aminoglycosides, quinolones, carbapenems, penicillin, and several other antibiotic classes [
Study populations, place, and duration: The study involved the collection of both data through a questionnaire and a swab sample from the oral cavity. Data and swab samples were collected from 55 oral cancer patients taking treatment from the National Institute of Cancer Research and Hospital, Dhaka, Bangladesh, from August 2019 to February 2020. The clinical samples were checked for the presence of infection on their cancer site. Another control group of 50 people was set with healthy volunteers aged over 22 who did not exhibit any cancer signs (
According to the guidelines provided by the Clinical Laboratory Standard Institute (CLSI), the antibiotic susceptibility pattern of the isolates was examined using the disc diffusion method [
Result from the growth of selective media: Of the 55 oral cancer patients involved in the study, all of them had an infection in their cancer site. Among them, 24 patients were postoperative patients and the remaining 31 were pre-operative patients. All the specimens from both pre-operative and post-operative patients exhibited bacterial growth on at least one selective media. Among those bacterial growths, (83; 65.4%) isolates were gram-negative bacteria and (44; 34.6%) isolates were Gram-positive bacteria. Among the Gram-positive bacteria, the most predominant bacteria were Staphylococcus spp. (24; 43.63%), followed by Streptococcus spp. (14; 25.45%) and Enterococcus spp. (6; 10.90%). Staphylococcus spp. is the highest found Gram-positive bacteria and in pre-operative patients, the number of Staphyloccocus spp. was more. Moreover, the most prevalent Gram-negative bacteria were Pseudomonas spp. (30; 54.54%) followed by Klebsiella spp. (27; 49.09%), E. coli (14; 25.45%), and Proteus spp. (12; 21.81%). Most isolated Gram-negative bacteria is Pseudomonas spp. and it is more prevalent in pre-operative patients. Again, of the 50 samples collected from the healthy people, which were considered the control group, 30 showed growth on the selective media used to isolate selected opportunistic pathogens. Among the pathogens found, 21 isolates were Gram-positive bacteria and 22 isolates were Gram-negative bacteria (
Identification of isolates from biochemical tests results: The individual colonies found from the selective media were streaked on nutrient agar to observe the colony morphology. Of the 127 isolated bacterial colonies from cancer patients, 83 isolates were Gram-negative bacteria and 44 isolates were Gram-positive bacteria. Again, 43 isolates were retrieved from 30 samples of the control group; 21 isolates were Gram-positive bacteria and 22 isolates were Gram-negative bacteria. Later, microorganisms were identified by standard biochemical tests (
Antibiotic susceptibility pattern of the isolates: The antibiotics used in the hospital for controlling the infection were selected for the susceptibility testing. The study tried to unveil the efficacy of the 13 commonly available antibiotics from 11 different groups for both gram-positive and gram-negative bacteria.
All the Gram-negative isolates from cancer patients were 100% resistant to Vancomycin, Amoxicillin, Penicillin G, and Metronidazole. The isolates’ resistance was followed by Azithromycin with 92.9% resistance, Nalidixic acid with 89.3% resistance, Tetracycline 88.1% resistance, and Amoxiclav 81% resistance. Isolates showed 16.7% resistance to Imipenem, 7.1% to Amikacin, and minimum resistance of 2.4% to Gentamicin (
The overall resistance shown isolated Klebsiella spp. from oral cancer patients was the maximum (70.9%) and Pseudomonas spp. has shown the least resistance (63.8%) among all the isolated Gram-Negative bacteria (
Again, all the Gram-positive isolates from cancer patients were resistant to Metronidazole, Erythromycin, Amoxicillin, Cloxacillin, Oxacillin. The isolates’
Type of bacteria | Post-op | Pre-op | Control group | Organism | Media |
---|---|---|---|---|---|
Gram-positive bacteria | 11 | 13 | 15 | Staphylococcus spp. | MSA media |
5 | 9 | 6 | Streptococcus spp. | KF Streptococcus Agar media | |
2 | 4 | - | Enterococcus spp. | KF Streptococcus Agar media | |
Gram-negative bacteria | 10 | 17 | 11 | Klebsiella spp. | EMB media |
6 | 6 | - | Proteus spp. | EMB media | |
5 | 9 | 3 | E. coli | EMB media | |
12 | 18 | 8 | Pseudomonas spp. | Cetrimide media |