Evaluation of different culture media for detection and quantification of H. pylori in environmental and clinical samples

Abstract

The objective of the present study was to establish the most suitable culture medium for the isolation of H. pylori from environmental and clinical samples.Ten different culture media were compared and evaluated. Four of them had been previously described and were modified in this study. The rest of the media were designed de novo. Three different matrices, tap water, wastewater, and feces, were inoculated with serial dilutions of H. pylori NCTC 11637 strain at a final concentration of 10 4 and 10 3 CFU/ml and the recovery rates were calculated.From inoculated tap water and wastewater samples, H. pylori colonies were recovered from four out of the analyzed culture media. When fecal samples were analyzed, the isolation of the pathogen under study was only possible from two culture media. Different optimal media were observed for each type of sample, even for wastewater and stool samples. Nevertheless, our results indicated that the combination of Dent Agar with polymyxin B sulfate did not inhibit the growth of H. pylori and was highly selective for its recovery, regardless of the sample origin. Thus, we propose the use of this medium as a diagnostic tool for the isolation of H. pylori from environmental and clinical samples, as well as for epidemiological studies.

Effect of dilution factor on the isolation of Helicobacter pylori from municipal wastewater using culture technique

“…Azevedo et al ( 37 ) noticed that the media which are too rich in nutrients may also cause a nutritional shock and prevent the growth of the bacteria. Thus, some of the authors are focused on evaluating different types of culture media for the detection and quantification of H. pylori in environmental samples ( 20 ). Besides the modifications in culture media, selective separation techniques like immunomagnetic beads for selective isolation of H. pylori were also applied based on the immunological properties of the bacterium.…”

“…Despite the disadvantages of culture techniques for the detection of VBNC forms of pathogens, this technique is the gold-standard method to detect viable H. pylori from environmental media when compared with molecular techniques. Furthermore, bacteria isolation is important for epidemiological and antimicrobial sensitivity analysis ( 20 ). Hortelano et al ( 20 ) suggested the optimization of cultivations techniques is essential for the isolation of H. pylori from environmental samples.…”

“…Furthermore, bacteria isolation is important for epidemiological and antimicrobial sensitivity analysis ( 20 ). Hortelano et al ( 20 ) suggested the optimization of cultivations techniques is essential for the isolation of H. pylori from environmental samples. Therefore, if culture methods can be optimized in any way to isolate this bacterium, then it is possible to measure or detect the presence of bacteria in environmental samples using culture methods, which are cheaper compared to molecular techniques.…”

“…As it is believed that starvation is the important VBNC state-inducing factor for H. pylori ( 22 , 25 ) and the isolation of H. pylori from wastewater is even more difficult due to the presence of contaminants ( 26 ), the wastewater dilution may be assumed as one of the factors increasing the chance of bacterial isolation from fresh wastewater. So far, few studies ( 20 ) have examined the effect of wastewater dilution on the isolation of bacteria using cultivation techniques from municipal wastewater.…”

Evolution of Diagnostic Methods for Helicobacter pylori Infections: From Traditional Tests to High Technology, Advanced Sensitivity and Discrimination Tools

“…The cultivation of H. pylori depends on the quality of biopsy samples, the delayed transport, exposure to the aerobic environment, and other factors, but it is essential for testing for susceptibility to antibiotics [ 58 , 59 , 60 , 61 ]. Host factors like low bacterial load, use of PPIs, antibiotics, alcohol, and bleeding can change the culture-positive rate.…”