The aim of the project was to determine any effect of hyperbaric air on Bacteroides fragilis strains cultivated under hyperbaric conditions. Previously, it was hypothesized that there was a correlation between the presence of Bacteroides bacteria in patients preferring a meaty diet and cancer of the small intestine, and particularly of the large intestine and rectum. With respect to the fact that Bacteroides fragilis (BAFR) group are important producers of endotoxins, measurement and statistical evaluation of endotoxin production by individual strains of isolated Bacteroides species were used to compare bacteria isolated from various clinical samples from patients with colon and rectum cancer in comparison with strains isolated from other non-cancer diagnoses. Endotoxin production was proven by quantitative detection using the limulus amebocyte lysate (LAL) test in EU/mL. Production of endotoxins in these bacteria cultured under hyperbaric air conditions was higher than those strains cultured under normobaric anaerobic conditions. But these differences in endotoxin production were not statistically significant (t test with log-transformed data, p value = 0.0910). Based on a two-tier t test for lognormal data, it is possible to cautiously conclude that a statistically significant difference was found between endotoxin production by Bacteroides fragilis strains isolated from non-carcinoma diagnoses (strains (1-6) and strains isolated from colorectal carcinoma diagnoses (strains 7-8; Wilcoxon non-parametric test p = 0.0132; t test = 0.1110; t test with log-transformed data, p value = 0.0294).
- MeSH
- Bacteroides fragilis chemie metabolismus MeSH
- endotoxiny metabolismus MeSH
- hyperbarická oxygenace MeSH
- kolorektální nádory mikrobiologie terapie MeSH
- kyslík * MeSH
- lidé MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
- Názvy látek
- endotoxiny MeSH
- kyslík * MeSH
OBJECTIVE: The aim of the study was to draw attention to the risk posed by anaerobic bacteria of the Bacteroides fragilis (BAFR) group, isolated particularly from abdominal lesions, and to assess the possible role of these species in colorectal cancer. A correlation has previously been suggested between the detection of the bacteria of the genus Bacteroides in patients on a meat-based diet and intestinal and, in particular, colorectal cancer. Given that the species of the BAFR group are major producers of endotoxins, measurements and statistical analysis of endotoxin production were used to compare the Bacteroides strains isolated from clinical specimens of patients with colon cancer, rectal cancer, and other abdominal lesions. MATERIALS AND METHODS: Endotoxin production was detected in bacterial strains of the BAFR group (B. fragilis, B. thetaiotaomicron, B. distasonis, and B. vulgatus) isolated from clinical specimens of patients with rectal cancer, colon cancer, and intestinal cancer and was compared with that in strains from samples of patients with inflammatory conditions (anal abscess, appendicitis, skin abscess, etc.) under anaerobic and microaerophilic (with 5% of oxygen) culture conditions. The production of endotoxins was detected quantitatively using the Pyrosate LAL assay kit (Limulus Amoebocyte Lysate Test, BIOGENIX, CR) in four species of the BAFR group after anaerobic and microaerophilic culture. Five strains of each isolated Bacteroides species from each type of specimens were tested (in total 140 BAFR strains). The amount of endotoxin was given in endotoxin units per ml (EU/ml). RESULTS: Endotoxin production by bacteria under microaerophilic culture conditions was several times higher in comparison with strictly anaerobic culture.The difference was statistically significant (F1.269 = 160, p <0.0001). As regards the effect of oxygen on endotoxin production, the amount of endotoxins produced under microaerophilic culture conditions (average 889.1 EU/ml) was 2.5 times as high as that observed under anaerobic culture conditions (358.2 EU/ml), regardless of the bacteroides species and diagnosis. These results suggest that the amount of free oxygen in the environment affects the amount of endotoxin generated by the Bacteroides strains. CONCLUSION: The results show that endotoxin production by the Bacteroides strains under microaerophilic culture conditions is several times as high as that under strictly anaerobic culture conditions.
- Klíčová slova
- Bacteroides fragilis group - endotoxins - colorectal carcinoma.,
- MeSH
- Bacteroides fragilis * účinky léků izolace a purifikace metabolismus patogenita MeSH
- dieta MeSH
- endotoxiny * analýza metabolismus MeSH
- kolorektální nádory mikrobiologie MeSH
- kyslík farmakologie MeSH
- lidé MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- endotoxiny * MeSH
- kyslík MeSH
A prerequisite for successful identification of anaerobic pathogenic bacteria from samples of clinical material is the method of cultivation. Currently, several methods of cultivation in anaerobic environment are used: cultivation in anaerobic box, anaerobic jar, and in nonrecurring cultivation system. Here, we determined the suitability of the above methods of cultivation using the estimation of the growth (diameters of colony size) of commonly isolated anaerobic pathogens (Bacteroides fragilis, Clostridium difficile, and Clostridium perfringens). The tested bacterial strains were exposed to atmospheric oxygen for various time periods and then they were cultivated using different anaerobic cultivation systems. Maximum growth differed, depending on the type of cultivation and the strain used. Thus, largest zone diameters, in the majority of measurements, were achieved in the anaerobic box. However, nonrecurring cultivation system seemed better in several cases; this applied to the cultivation of C. perfringens after 15, 30, and 60 min exposure to atmospheric oxygen as well as the cultivation of B. fragilis after 30 and 60 min of oxygen exposure. The cultivation in anaerobic box was the most convenient method for growth of C. difficile. In almost all cases, higher growth was observed in nonrecurring cultivation system than in the system of anaerobic jar. On the other hand, no significant differences were observed among these anaerobic cultivation systems which confirmed their applicability (taking into account some individual features concerning the optimization of cultivations) for identification of pathogenic anaerobes.
- MeSH
- anaerobióza MeSH
- anaerobní bakterie metabolismus MeSH
- Bacteroides fragilis metabolismus MeSH
- Clostridioides difficile metabolismus MeSH
- Clostridium perfringens metabolismus MeSH
- klostridiové infekce mikrobiologie MeSH
- kyslík metabolismus MeSH
- lidé MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- kyslík MeSH
BACKGROUNDS: Members of the Bacteroides fragilis group are the most frequently isolated anaerobic bacteria causing a wide range of severe anaerobic infections. In spite of the high frequency of their occurrence, their presence in clinical specimens is underestimated or even disregarded. The article warns of the severity of these anaerobic pathogens, particularly if detected in clinical samples from the abdominal area. It was hypothesized that there is a correlation between the presence of the bacteria in patients preferring high-meat diet and cancers of the small intestine and especially the colon and rectum [10]. Endotoxins of the bacteria contribute to weakening the patient's immune system damaged by cancer and play a significant role in the progression of small intestine and colon cancer. MATERIAL AND METHODS: Endotoxin production was determined in 140 strains of the Bacteroides fragilis group (B. fragilis, B. thetaiotaomicron, B. distasonis, B. vulgatus) isolated from patients with 7 cancerous and non-cancerous diseases (5 strains of each type of Bacteroides spp. for each diagnosis), using the Pyrosate LAL (limulus amoebocyte lysate) assay. RESULTS: A statistically significant difference in the production of endotoxins isolated from strains of the Bacteroides fragilis group was found between cancerous and non-cancerous diseases. CONCLUSIONS: All four bacterial species produced significantly more endotoxins in cancer than in non-cancerous diseases, with the lowest production in skin abscess (F2,134 = 170, p < 0.0001). Statistically significant differences in the production of endotoxins were also found between the individual members of the Bacteroides fragilis group. B. fragilis and B. vulgatus produced significantly more of (twice as much) endotoxin than B. distasonis and B. thetaiotaomicron (post hoc t-tests, p < 0.00001).
- MeSH
- Bacteroides fragilis metabolismus MeSH
- endotoxiny biosyntéza MeSH
- infekce bakteriemi rodu Bacteroides komplikace MeSH
- kolorektální nádory mikrobiologie MeSH
- lidé MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- anglický abstrakt MeSH
- časopisecké články MeSH
- Názvy látek
- endotoxiny MeSH
- MeSH
- Bacteroides fragilis imunologie metabolismus MeSH
- bakteriální toxiny imunologie izolace a purifikace toxicita MeSH
- králíci MeSH
- myši MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- anglický abstrakt MeSH
- časopisecké články MeSH
- Názvy látek
- bakteriální toxiny MeSH
