Original Article DOI: 10.7860/NJLM/2016/21674:2158 Comparison of Different Diagnostic Methods of Helicobacter pylori in Microbiology Section Microbiology Dyspeptic Patients of a Tertiary Care Hospital of Uttarakhand, India SHIWANI SHARMA, GARIMA MITTAL, R K AGARWAL, VIVEK AHUJA, ROHIT GUPTA, SOHAIB AHMAD ABSTRACT all the patients were also screened for H.pylori stool antigen Introduction: Helicobacter pylori (H.pylori) infection is very (HpSA) test. Bacterial culture was considered as gold standard common worldwide. A reliable diagnosis is crucial for better in this study and other diagnostic tests were compared with the treatment of the patients. However, there is no single diagnostic gold standard. method that can meet the criteria in identification of H.pylori. Results: Out of 100 patients H.pylori was detected by bacterial Aim: To detect H.pylori from endoscopic biopsies in dyspeptic culture, RUT, CTU and HpSA in 34%, 61%, 53% and 28% patients and to compare the sensitivity and specificity of cases respectively. Sensitivity of RUT, CTU and HpSA were different diagnostic methods for H. pylori infection. 100%, 91% and 73.5% respectively and specificity of RUT, CTU and HpSA were 59%, 66.7% and 95.3% respectively. Materials and Methods: This observational and cross- Thus, RUT was the most sensitive (100%) and HpSA (95.3%) sectional study was conducted in the Department of was the most specific test, when culture was being considered Microbiology and Medicine, Himalayan Institute of Medical as gold standard. Sciences (HIMS), Swami Ram Nagar, Dehradun, over a period of 12 months. Biopsies of gastric antrum from 100 patients with Conclusion: RUT is best considered as a screening test and dyspepsia were studied for the detection of H.pylori by various not as the gold standard for H. pylori. The HpSA test is also methods like bacterial culture, Rapid Urease Test (RUT) and rapid, simple and non-invasive test with acceptable results that Christensen‘s Tube Urease (CTU) test. Stool samples from can be used for monitoring. Keywords: Bacterial culture, Christensen‘s tube urease test, Rapid urease test, Stool antigen test (HpSA) INTRODUCTION There are several invasive and non-invasive techniques Helicobacter pylori (H.pylori) is a spiral shaped, used to diagnose H. pylori infection, each having its own microaerophilic, motile, flagellated gram negative bacterium advantages and disadvantages. Invasive methods require which has been recognised as the most common cause of biopsy samples from stomach and duodenum and can be chronic human bacterial infection affecting up to 50% of the tested by various methods such as histology, Rapid Urease world’s population [1,2]. The discovery of H.pylori in 1984 by Test (RUT), microbiological culture and Polymerase Chain Warren and Marshall represents one of the most important Reaction (PCR) whereas non-invasive tests include stool developments in medicine of the past century [3]. antigen test, serology and Urea Breath Test (UBT). The choice of the test is governed by several factors like clinical condition Infection results in persistent chronic gastritis lasting for of the patient, cost of the test and its sensitivity and specificity many years possibly life long, such gastritis is thought to [7]. But, all these tests have their own limitations due to faulty be involved in the possible sequence of gastric mucosal technique in collecting biopsy samples, observer related atrophy, intestinal mucosal metaplasia, Mucosa Associated variations, distribution of H. pylori in stomach and type of stain Lymphoid Tissue (MALT) lymphoma and gastric carcinoma. used. These factors may sometimes give false results [8]. Most H.pylori infections are probably acquired in childhood and adolescence [4]. The prevalence of H.pylori infection The purpose of this study was to detect H.pylori from is 25%-50% in developed countries and 70%-90% in endoscopic biopsies in dyspeptic patients and to compare developing countries [5]. The most probable mode of the sensitivity, specificity, Positive Predictive Value (PPV) transmission is person-to-person spread but oral-oral and and Negative Predictive Value (NPV) of different diagnostic faecal-oral transmissions have also been reported [6]. methods for H. pylori infection. 6 National Journal of Laboratory Medicine. 2016 Oct, Vol-5(4): MO06-MO10 www.njlm.net Shiwani Sharma et al., Different Diagnostic Methods of Helicobacter pylori in Dyspeptic Patients MatERIALS AND METHODS Christensen’s Tube Urease Method (CTU): Christensen’s This observational and cross-sectional study was conducted urease medium was prepared in our Microbiology laboratory in the Department of Microbiology and Medicine, Himalayan using distilled water, phenol red as indicator, glucose and Institute of Medical Sciences (HIMS), Swami Ram Nagar, urea. It was inoculated directly with the crushed biopsy Dehradun, over a period of 12 months. A total of 100 adult material and incubated at room temperature. A positive dyspeptic patients who had undergone upper gastrointestinal control Proteus mirabilis (ATCC 29906) and a negative endoscopy from July 2014 to June 2015 were enrolled in control E.coli (ATCC 25922) were put up for each test. The this study. test was read after half hour, 1 hour, 4 hour, 6 hour and 12 hours of incubation. The test was considered positive when Inclusion criteria: Adult patients (>18 years) who presented the colour changed from yellow to red [9]. with dyspeptic symptoms to the Gastroenterology OPD requiring upper GI endoscopy. H. pylori Stool Antigen Test (HpSA): Stool specimens were analysed using a commercially available kit i.e. SD BIO Exclusion criteria: Patients who had taken antibiotics during LINE H.pylori Ag detection kit (Standard Diagnostic, Inc., past two weeks, active GI bleeding, pregnancy and history Republic of Korea) according to manufacturer’s protocol. of gastrectomy. It is a non-invasive method for the detection of H.pylori History of risk factors like alcohol intake, smoking, excessive infection. Test device and stool sample were allowed to intake of tea or coffee and stress were taken to see whether settle to room temperature. Assay diluent was taken in the any statistical significance with H. pylori infection was there sample collection tube and with the help of swab, a portion or not. of faeces about 500 mg was taken and inserted into the Written informed consent was obtained from all the patients sample collection tube containing assay diluent, three drops before endoscopy and sample collection. Approval from of this mixture (assay diluent and stool sample) were added Institutional ethical committee was taken prior to initiation into the sample well of the test device. Interpretation of test of this study. result was done within 10-15 minutes. The presence of two Endoscopy and biopsy sampling: Endoscopy was carried colour bands as test band (T) and control band (C) within out using Olympus GIF Q150 and KARL STORZ 13801 PKS the result window indicated a positive result. The presence on patients after an overnight fast. Three biopsy specimens of only control band (C) within the result window indicated a from mucosa of the gastric antrum were obtained by negative result as per the kits instruction. endoscopy and were placed in a small screw capped bottle containing 0.2 mL sterile normal saline to maintain RESULTS humidity. Out of these three biopsy samples, one was sent Out of the 100 enrolled patients in this study, 75 were males to bacteriology laboratory for bacterial culture, second was and 25 were females. Out of the 34 culture positive patients, used for rapid urease test and last one for Christensen’s 28 (82.4%) were males and 6 (17.6%) were females. This Keywords: Bacterial culture, Christensen‘s tube urease test, Rapid urease test, Stool antigen test (HpSA) tube urease test. was not found to be statistically significant (p-value=0.22). Bacterial culture: Culture was done by direct plating from The age of the patients ranged from 18 to 70 years with biopsy samples. The media used was BBLTM Brucella agar a mean age of 40.34±12.35 years. Maximum numbers of (Becton, Dickinson and Company, USA), with 5% defibrinated patients were in the age group 31-40 years (29%). sheep blood. The inoculated plates were incubated at 37ºC The patients presented with various symptoms, the for three days in a microaerophilic environment which was commonest being pain abdomen (77%), nausea and provided by Campypak (BD Gas Pack). The isolated bacteria vomiting (75% and 65%) and dyspeptic symptoms (68%). were identified by its colony morphology, microscopy and Loss of appetite was seen in 40%, alteration in bowel habits biochemical tests i.e. positive catalase, oxidase and urease in 20% and weight loss in 12% of total patients [Table/ test [9]. Fig-1]. Risk factors like alcohol intake (p-value=0.502), Rapid Urease Test (RUT): One gastric biopsy sample was smoking (p-value=0.61), excessive intake of tea or coffee screened by commercial rapid urease kit i.e. RUT DRY (p-value=0.48), and stress (p-value=0.33), did not show any Test kit (Gastro Cure System, Kolkata, WB, India) available statistical significance with H. pylori infection. at pharmacy store of our HIMS hospital. Here the biopsy Seventy-one percent patients had gastritis on endoscopy sample was directly put into the well of kit. The urease followed by gastric ulcers (3%) and gastric erosions (2%). enzyme produced by H.pylori rapidly hydrolyses urea in the Normal findings were seen in 24% dyspeptic patients. 32 out well, producing ammonia. The rise in the pH of the medium of 71 (45.1%) were found to be culture positive, which was by ammonium ions can be detected with a pH indicator [9]. statistically significant with odds ratio of 11.07 (95%CI: 2.4- Immediately, there was change in colour to pink, in case of 50.2) and p-value of 0.0006.