Rustam Khan

Prevalence of non Helicobacter pylori species in patients presenting with dyspepsia

BackgroundHelicobacter species associated with human infection include Helicobacter pylori, Helicobacter heilmannii and Helicobacter felis among others. In this study we determined the prevalence of H. pylori and non-Helicobacter pylori organisms H. felis and H. heilmannii and analyzed the association between coinfection with these organisms and gastric pathology in patients presenting with dyspepsia. Biopsy specimens were obtained from patients with dyspepsia on esophagogastroduodenoscopy (EGD) for rapid urease test, histology and PCR examination for Helicobacter genus specific 16S rDNA, H. pylori phosphoglucosamine mutase (glmM) and urease B (ureB) gene of H. heilmannii and H. felis. Sequencing of PCR products of H. heilmannii and H. felis was done.ResultsTwo hundred-fifty patients with dyspepsia were enrolled in the study. The mean age was 39 ± 12 years with males 162(65%). Twenty-six percent (66 out of 250) were exposed to cats or dogs. PCR for Helicobacter genus specific 16S rDNA was positive in 167/250 (67%), H. pylori glmM in 142/250 (57%), H. heilmannii in 17/250 (6%) and H. felis in 10/250 (4%), respectively. All the H. heilmannii and H. felis PCR positive patients were also positive for H. pylori PCR amplification. The occurrence of coinfection of H. pylori and H. heilmannii was 17(6%) and with H. felis was 10(4%), respectively. Only one out of 66 exposed to pets were positive for H. heilmannii and two for H. felis. Histopathology was carried out in 160(64%) of 250 cases. Chronic active inflammation was observed in 53(56%) (p = 0.001) of the patients with H. pylori infection alone as compared to 3(37%) (p = 0.73) coinfected with H. heilmannii and H. pylori and 3(60%) coinfected with H. felis and H. pylori (p = 0.66). Intestinal metaplasia was observed in 3(3%)(p = 1.0) of the patients with H. pylori infection alone as compared to 2(25%) (p = 0.02) coinfected with H. heilmannii and H. pylori and 1(20%) coinfected with H. felis and H. pylori (p = 0.15).ConclusionThe prevalence of H. heilmannii and H. felis was low in our patients with dyspepsia. Exposure to pets did not increase the risk of H. heilmannii or H. felis infection. The coinfection of H. pylori with H. heilmannii was seen associated with intestinal metaplasia, however this need further confirmation.

Small intestinal bacterial overgrowth and lactose intolerance contribute to irritable bowel syndrome symptomatology in Pakistan

Background /Aim: The symptoms of irritable bowel syndrome resemble those of small intestinal bacterial overgrowth (SIBO). The aim of this study was to determine the frequency of SIBO and lactose intolerance (LI) occurrence in patients with diarrhea-predominant irritable bowel syndrome (IBS-D) according to Rome III criteria. Patients and Methods: In this retrospective case-control study, patients over 18 years of age with altered bowel habit, bloating, and patients who had lactose Hydrogen breath test (H2BT) done were included. The “cases” were defined as patients who fulfill Rome III criteria for IBS-D, while “controls” were those having chronic nonspecific diarrhea (CNSD) who did not fulfill Rome III criteria for IBS-D. Demographic data, predominant bowel habit pattern, concurrent use of medications, etc., were noted. Results: Patients with IBS-D were 119 (51%) with a mean age of 35 ± 13 years, while those with CNSD were 115 (49%) with mean age 36 ± 15 years. Patients in both IBS-D and CNSD were comparable in gender, with male 87 (74%) and female 77 (64%). SIBO was documented by lactose H2BT in 32/234 (14%) cases. It was positive in 22/119 (19%) cases with IBS-D, while 10/115 (9%) cases had CNSD (P = 0.03). LI was positive in 43/234 (18%) cases. Of these, 25/119 (21%) cases had IBS-D and 18/115 (16%) cases had CNSD (P = 0.29). Conclusion: SIBO was seen in a significant number of our patients with IBS-D. There was no significant age or gender difference in patients with or without SIBO.

Medical interns knowledge of TB in Pakistan.

Of 460 interns from five Pakistani teaching hospitals surveyed, only 22% correctly identified the estimated number of new TB cases in Pakistan. The majority (96%) knew that droplet infection was the usual mode of transmission. Only 38% considered sputum smears for acid-fast bacilli as the best test for diagnosis of pulmonary TB and 43.5% for follow-up during TB treatment. The recommended four-drug anti-TB regimen was prescribed by 56.5% in the initiation phase and the recommended two-drug combination in the continuation phase by 52%. Most interns (82%) were unable to identify a single component of directly observed treatment short course (DOTS) strategy. Our study reflects poor awareness of and low compliance to the World Health Organization/National Tuberculosis Programme guidelines among interns. For effective control of TB, immediate action to improve undergraduate and continuing medical education is essential, with special emphasis on national guidelines.

Risk factors associated with Helicobacter pylori infection treatment failure in a high prevalence area

Triple therapy is commonly used for the treatment of Helicobacter pylori infection. We determined risk factors associated with its failure in compliant patients focusing on H. pylori density, virulence marker and 23S ribosomal RNA (rRNA) point mutations associated with clarithromycin resistance. H. pylori infection was diagnosed by 14C urea breath test (14C UBT) and rapid urease test or histology. Triple therapy with esomeprazole 20 mg b.i.d., amoxicillin 1 g b.i.d. and clarithromycin 500 mg b.i.d. was prescribed for 10 days. 14C UBT was repeated 4 weeks after treatment. In total, 111 patients [69 (62%) males] with a mean age of 46±16 years were enrolled. The mean age of treatment failure was 39±14 years compared to 48±16 years with eradication (P=0·002). Treatment failure was associated with younger mean age, point mutations in the 23S rRNA gene of H. pylori and vacA s1a and m1 when associated with cagA negativity.

Prevalences of Giardia lamblia and Cryptosporidium parvum infection in adults presenting with chronic diarrhoea.

Abstract Giardia lamblia and Cryptosporidium parvum are both waterborne pathogens associated with diarrhoea in developing countries. In a recent study based at the Aga Khan University in Karachi, 334 adults aged 16–83 years (178 patients with chronic diarrhoea and 156 diarrhoea-free volunteers who acted as controls) were checked for infection with these parasites, using stool microscopy and/or PCR. Overall, 21 (6.3%) and 29 (8.7%) of the subjects were found positive for G. lamblia by microscopy and PCR, respectively, while the corresponding values for C. parvum were 13 (3.9%) and 14 (4.2%). Although, compared with the diarrhoea-free controls, the patients with diarrhoea were not significantly more likely to be found infected with Giardia, either by microscopy [15 (8.4%) v. six (3.8%); P=0.085] or PCR [19 (10.7%) v. 10 (6.4%); P=0.167], they were significantly more likely to be found infected with C. parvum, both by microscopy [11 (6.2%) v. two (1.3%); P=0.024] and by PCR [12 (6.7%) v. two (1.3%); P=0.014]. The 19 patients found PCR-positive for Giardia comprised 10 (67%) of the 15 found smear-positive for the same parasite but only nine (5%) of the 163 found smear-negative (k=0.545; P<0.001). Similarly, the 12 patients found PCR-positive for Cryptosporidium comprised all 11 (100%) patients found smear-positive for the same parasite but only one (0.6%) of the 167 found smear-negative (k=0.954; P<0.001). Although C. parvum was associated with chronic diarrhoea in the present study, the carriage of G. lamblia often appeared asymptomatic.

Entamoeba species associated with chronic diarrhoea in Pakistan

We determined the prevalence of Entamoeba (E.) histolytica, E. dispar and E. moshkovskii in patients with chronic diarrhoea associated with abdominal pain or discomfort mimicking irritable bowel syndrome. Stool samples were collected from 161 patients with chronic diarrhoea and from 157 healthy controls. Stool microscopy with modified trichrome stain, culture and polymerase chain reaction (PCR) for Entamoeba spp. differentiation was performed. Microscopy demonstrated Entamoeba cysts in 44% (57/129) of patients with diarrhoea compared to 29% (44/151) of controls (P=0·009). In patients with diarrhoea, PCR for E. histolytica was positive in 9% (11/129) (P=0·008), E. dispar in 19% (24/129) (P=0·117) and E. moshkovskii in 19% (24/129) (P<0·001). E. histolytica and E. moshkovskii were significantly associated with diarrhoea while E. dispar was found equally in both groups.

Microsporidial infections due to encephalitozoon intestinalis in non-HIV-infected patients with chronic diarrhoea.

We determined the prevalence of microsporidia Enterocytozoon (Ent.) bieneusi and Encephalitozoon (E.) intestinalis infection in patients with chronic diarrhoea and hepatocellular carcinoma (HCC). A total of 330 stool samples were examined from 171 (52%) patients with chronic diarrhoea, 18 (5%) with HCC while 141 (43%) were controls. Stool microscopy, polymerase chain reaction (PCR) with species-specific primers for Ent. bieneusi and E. intestinalis and sequencing were carried out. Microsporidia were found by trichrome staining in 11/330 (3%) and E. intestinalis by PCR in 13/330 (4%) while Ent. bieneusi was not detected. PCR for E. intestinalis was positive in 8/171 (5%) stool samples from patients with chronic diarrhoea, 2/141 (1·4%) samples from healthy controls and in 3/18 (17%) samples from patients with HCC. In the chronic diarrhoea group, E. intestinalis was positive in 4/171 (2·3%) (P=0·69) stool samples compared to 2/18 (11%) (P=0·06) in the HCC group and 2/141 (1·4%) from healthy controls. E. intestinalis infection was significantly associated with chronic diarrhoea and HCC in these patients who were negative for HIV. Stool examination with trichrome or species-specific PCR for microsporidia may help establish the cause of chronic diarrhoea.

Low prevalence of the intact cag pathogenicity island in clinical isolates of Helicobacter pylori in Karachi, Pakistan.

Abstract Clinical diseases that follow Helicobacter pylori infection are associated with expression of the cagA gene, a part of cytotoxin-associated gene pathogenicity island (cag-PAI). This study aims to determined whether or not the presence of cagA is associated with the presence of complete cag-PAI and to evaluate inflammatory changes associated with the five loci in the cag-PAI of H. pylori comprising cagA, cagA promoter region (cagAP), cagE, cagT and the left end of the cagA gene (LEC). H. pylori isolates were obtained from patients with dyspeptic symptoms. Clinical strains of H. pylori were screened by the polymerase chain reaction (PCR) for respective genes of the cag-PAI. Of 115 H. pylori isolates, 31 (28%) were positive for the five cag-PAI loci. H. pylori isolates with intact cag-PAI were associated with gastric carcinoma (GC; n=9[60%]) and gastric ulcer (GU; n=5[45%]) compared to non-ulcer dyspepsia (NUD; n=14[18%]) (P=0.001 and P=0.049, respectively). In patients with intact cag-PAI, acute on chronic inflammation was present in 25 (81%) and was more common than chronic inflammation (P=0.013). The cagE and cagAP had deletions in 25 (37%) and 23 (35%) cases, respectively. The cagAP region was significantly associated with GC (n=12[80%], P<0.001) and GU (n=9[82%], P=0.001) compared to NUD (n=24[30%] and with significant acute on chronic inflammation (n=40[80%], P=0.007). The distribution of vacAs1a with intact cag-PAI in GC was 9(60%) and in NUD was 10(13%) (P<0.001). The presence of the cagA gene does not signify presence of an intact cag-PAI. Most of the H. pylori isolates studied had partial cag-PAI with missing cagE and cagA promoter regions.

Helicobacter pylori outer membrane protein Q allele distribution is associated with distinct pathologies in Pakistan

Helicobacter pylori (H. pylori) strains expressing outer membrane protein Q (HopQ) promote adherence to the gastric epithelial cell. We characterized HopQ alleles in relation to H. pylori-related disease, histology and virulence markers. Gastric biopsies were obtained at esophagogastroduodenoscopy from patients with upper gastrointestinal symptoms. H. pylori culture, histology and polymerase chain reaction (PCR) for HopQ types, cagA, cagA-promoter and vacA alleles were performed. DNA extracted was used for PCR. Sequencing of PCR products of HopQ types 1 and 2 was followed by BLAST query. We examined 241 H. pylori isolates. HopQ type 1 was positive in 70 (29%) isolates, type 2 in 60 (25%) isolates, while both type 1 and type 2 in 111 (46%) H. pylori isolates, respectively. Nonulcer dyspepsia (NUD) was associated with HopQ type 2 in 48 (41%) isolates, while gastric carcinoma (GC) in 37 (53%) (P<0.001) with type 1 isolates. Gastric ulcers (GU) were 39 (46%) (P<0.001) in H. pylori infection with multiple HopQ alleles compared to 6 (23%) in HopQ type 1. Multivariate analysis demonstrated that multiple HopQ alleles were associated with GU OR 2.9 (1.07-7.8) (P=0.03). HopQ type 1 was associated with cagA 58 (84%) (P<0.001) and cagA-promoter 58 (83%) (P<0.001) compared to 14 (23%) and 17 (28%) respectively, in type 2. VacAs1a was associated with HopQ type 1 in 59 (84%) isolates compared to HopQ type 2 in 35 (58%) (P=0.002) isolates. VacAm1 was associated with HopQ type 1 in 53 (76%) isolates compared to HopQ type 2 in 32 (53%) (P=0.004) isolates. H. pylori infection with multiple HopQ alleles was predominant. H. pylori infection with single HopQ type 1 was associated with GC in the presence of other H. pylori virulence markers.

Helicobacter pylori: correlation of the virulence marker iceA allele with clinical outcome in a high prevalence area.

ABSTRACT The association of Helicobacter pylori virulence marker ‘induced by contact with epithelium A’ (iceA) allele types was determined in H.pylori-related diseases and virulence markers. Gastric biopsies were obtained at EGD from patients for culture, histopathology and polymerase chain reaction (PCR) for iceA types, cagA and vacA alleles. Two hundred and eighty-four H. pylori isolates were examined. iceA type1 was positive in 177 (62%) and iceA type 2 in 158 (56%). In iceA type 2, gastric ulcer was present in 34 (21%) (P<0.001) and carcinoma in 28 (25%) (P=0.002), compared to nine (8%) and 2 (2%) in iceA type 2-negative cases. For iceA type 2, 139 (88%) were associated with chronic active gastritis compared to 95 (75%) (P=0.006) in iceA type 2- negative. H. pylori cagA was positive in 101 (64%) iceA type 2 strains compared to 57 (45%) in negative strains (P=0.002). H. pylori iceA type 2 was dominant and associated with cagA, chronic active inflammation, gastric ulcer and carcinoma.