Abstract
Helicobacter pylori is recognized by the World Health Organization to be the primary cause of peptic ulcers, chronic gastritis, and stomach cancer, though the source of human infection is not well understood. One of the problems in understanding the source of human contamination is the difficulty in isolating the organism from the environment. However, the combination of PCR results with those of culturing of 471 drinking water samples can provide a more accurate picture of H. pylori detection. In this method 78 presumptive H. pylori colonies out of 266 tap water samples were obtained in the preliminary detection on modified Columbia agar (MCUA) slant relying on urease positivity with a rate of 29.3%. However, only 11 out of them were confirmed by Gram staining and biochemical tests reducing the rate to 4.13% whereas only 3 (1.46%) from 205 reverse osmosis (RO) water samples. Furthermore, only 6 (54.5%) out of the 11 isolates from tap water and 1 (33.3%) of the 3 RO isolates were confirmed by 16SrRNA PCR. Thus PCR confirmation reduced the rate to 2.2%. In addition, only 4 (4%) of 100 tap water samples negative for H. pylori by culture method were H. pylori positive by 16SrRNA. Water samples were collected from 24 districts of Basrah Governorate from February–December 2009. The direct recovery of H. pylori from drinking water is both alarming and scientifically exciting in terms of the investigation of its epidemiology.
Highlights
Helicobacter pylori is recognized as the major cause of gastritis and peptic ulcer and gastric mucosa-associated lymphoid tissue (MALT) gastric lymphoma [1]
Out of 471 water samples, 14 (2.76%) isolates of H. pylori were isolated from samples taken from 14 districts by culture method and identified by biochemical tests
The modified Columbia urea agar using monophasic-diphasic culture setup (MDCS) method preliminarily revealed the presence of H. pylori in water samples, correlated with the change in the color of the slant modified Columbia agar (MCUA) tube from orange to pink that occurred at the same time giving an additional evidence for the presence of H. pylori in the samples (Figure 1)
Summary
Helicobacter pylori is recognized as the major cause of gastritis and peptic ulcer and gastric mucosa-associated lymphoid tissue (MALT) gastric lymphoma [1]. The mechanism of H. pylori pathogenic effect is unclear but is believed to be related to host bacterial interactions initiated by virulence genes, and it is possible that these effects are enhanced by invasiveness of the bacterium [2,3,4,5]. Polymerase chain reaction (PCR) methods have been used to detect H. pylori as its 16SrRNA gene sequence analysis unambiguously differentiated the Helicobacter genus from the closely related Campylobacter genus and other Helicobacter species [9]. The presence of H. pylori in drinking water which was detected by PCR has been reported from several countries [10,11,12]. Hegarty et al [13] demonstrated the presence of respiring H. pylori from US surface water. The prevalence of disease attributed to H. pylori in Iraq is not available despite of its commonality
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