Characterization of Domain V Mutations in Clinical Isolates of Helicobacter pylori in Pakistan and Their Effect on Clarithromycin MIC.

PURPOSE: Clarithromycin is commonly prescribed for H. pylori infection. Domain V mutations are responsible for clarithromycin resistance. This study was aimed to characterize the clarithromycin resistance and its associated mutations in clinical isolates of H. pylori in Pakistan. MATERIALS AND METHODS: Infection was diagnosed in 93 patients' biopsies using culture, rapid urease test, 16S rRNA, and vacA gene multiplex PCR. Clarithromycin resistance was assessed by the agar dilution method. Mutations were detected by PCR-RFLP using 46 (1.4 kb) domain V fragments. Sequencing was executed for 13 domain V fragments, of which 12 showed unusual amplicon size (1.2 kb) and 01 had a new MboII RFLP pattern. RESULTS: A total of 48 (83%) strains were obtained from 58 (62.3%) PCR H. pylori-positive samples. Resistance (MIC ≥ 0.001 mg/mL) and intermediate resistance phenotype (MIC = 0.0005 mg/mL) was observed in 22 (46%), and 10 (21%) isolates, respectively. The primary resistance was found in 23 (39.6%) samples. PCR-RFLP detected A2142G, A2143G, and double mutations in 19, 04, and 01 resistant strain, respectively. Sequencing of 10 amplicons obtained from intermediated resistant strains and 03 amplicons from resistant strains showed 138 new mutations. Among them, T2182C was also seen in 04 intermediated resistant isolates, whereas A2142G, A2143G, and A2143C were observed in resistant isolates. The new MboII RFLP pattern in an intermediated resistant strains was due to A1761G mutation. CONCLUSION: H. pylori domain V mutations showed extensive diversity. Multiple mutations in domain V may give endurance to H. pylori against clarithromycin. Further investigations on the molecular mechanism of antibiotic resistance in H. pylori seem crucial at this stage.

Using single-operator cholangioscopy for endoscopic evaluation of indeterminate biliary strictures: results from a large multinational registry.

BACKGROUND: Peroral cholangioscopy (POCS) of indeterminate biliary strictures aims to achieve a diagnosis through visual examination and/or by obtaining targeted biopsies under direct visualization. In this large, prospective, multinational, real-life experience of POCS-guided evaluation of indeterminate biliary strictures, we evaluated the performance of POCS in this difficult-to-manage patient population. METHODS: This prospective registry enrolled patients, with indeterminate biliary strictures across 20 centers in Asia, the Middle East, and Africa. The primary end points were the ability to visualize the lesion, obtain histological sampling when intended, and an assessment of the diagnostic accuracy of POCS for malignant strictures. Patients were followed for 6 months after POCS or until a definitive malignant diagnosis was made, whichever occurred first. RESULTS: 289 patients underwent 290 POCS procedures with intent to biopsy in 182 cases. The stricture/filling defect was successfully visualized in 286/290 (98.6 %), providing a visual diagnostic impression in 253/290 (87.2 %) and obtaining adequate biopsies in 169/182 (92.9 %). Procedure-related adverse events occurred in 5/289 patients (1.7 %). POCS influenced patient management principally by elucidating filling defects or the causes of bile duct stricture or dilation. The visual impression of malignancy showed 86.7 % sensitivity, 71.2 % specificity, 65.8 % positive and 89.4 % negative predictive value, and 77.2 % overall accuracy compared with final diagnosis. Histological POCS-guided samples showed 75.3 % sensitivity, 100 % specificity, 100 % positive and 77.1 % negative predictive value, and 86.5 % overall accuracy. CONCLUSION: In this large, real-life, prospective series, POCS was demonstrated to be an effective and safe intervention guiding the management of patients with indeterminate biliary strictures.

Cholangioscopy-guided lithotripsy for difficult bile duct stone clearance in a single session of ERCP: results from a large multinational registry demonstrate high success rates.

BACKGROUND: Peroral cholangioscopy (POCS) can be useful for difficult bile duct stone clearance. Large prospective multinational data on POCS-guided lithotripsy for clearing difficult bile duct stones in a single session of endoscopic retrograde cholangiopancreatography (ERCP) are missing. METHODS: Patients with difficult bile duct stones (defined as one or more of: largest stone diameter ≥ 15 mm, failed prior attempt at stone clearance, impacted, multiple, hepatic duct location, or located above a stricture) were enrolled at 17 centers in 10 countries. The principal endpoint was stone clearance in a single ERCP procedure using POCS. RESULTS : 156 patients underwent 174 sessions of POCS-guided electrohydraulic or laser lithotripsy. Stone clearance had failed in a previous ERCP using traditional techniques in 124/156 patients (80 %), while 32 /156 patients (21 %) were referred directly to POCS-guided therapy based on preprocedural assessment of the difficulty of stone clearance. In 101/156 patients (65 %), there were impacted stones. POCS-guided stone clearance was achieved in a single POCS procedure in 125 /156 patients (80 %, 95 % confidence interval [CI] 73 % - 86 %), and was significantly more likely for stones ≤ 30 mm compared with > 30 mm (odds ratio 7.9, 95 %CI 2.4 - 26.2; P = 0.002). Serious adverse events occurred in 3/156 patients (1.9 %, 95 %CI 0.4 % - 5.5 %), and included pancreatitis, perforation due to laser lithotripsy, and cholangitis (n = 1 each), all resolved within 1 week. CONCLUSION: POCS-guided lithotripsy is highly effective for clearance of difficult bile duct stones in a single procedure and successfully salvages most prior treatment failures. It may also be considered first-line therapy for patients with difficult choledocholithiasis to avoid serial procedures.

Knowledge of, attitudes toward, and barriers to participation of colorectal cancer screening tests in the Asia-Pacific region: a multicenter study.

BACKGROUND: The rapid increase in the incidence of colorectal cancer (CRC) in the Asia-Pacific region in the past decade has resulted in recommendations to implement mass CRC screening programs. However, the knowledge of screening and population screening behaviors between countries is largely lacking. OBJECTIVE: This multicenter, international study investigated the association of screening test participation with knowledge of, attitudes toward, and barriers to CRC and screening tests in different cultural and sociopolitical contexts. METHODS: Person-to-person interviews by using a standardized survey instrument were conducted with subjects from 14 Asia-Pacific countries/regions to assess the prevailing screening participation rates, knowledge of and attitudes toward and barriers to CRC and screening tests, intent to participate, and cues to action. Independent predictors of the primary endpoint, screening participation was determined from subanalyses performed for high-, medium-, and low-participation countries. RESULTS: A total of 7915 subjects (49% male, 37.8% aged 50 years and older) were recruited. Of the respondents aged 50 years and older, 809 (27%) had undergone previous CRC testing; the Philippines (69%), Australia (48%), and Japan (38%) had the highest participation rates, whereas India (1.5%), Malaysia (3%), Indonesia (3%), Pakistan (7.5%), and Brunei (13.7%) had the lowest rates. Physician recommendation and knowledge of screening tests were significant predictors of CRC test uptake. In countries with low-test participation, lower perceived access barriers and higher perceived severity were independent predictors of participation. Respondents from low-participation countries had the least knowledge of symptoms, risk factors, and tests and reported the lowest physician recommendation rates. "Intent to undergo screening" and "perceived need for screening" was positively correlated in most countries; however, this was offset by financial and access barriers. LIMITATIONS: Ethnic heterogeneity may exist in each country that was not addressed. In addition, the participation tests and physician recommendation recalls were self-reported. CONCLUSIONS: In the Asia-Pacific region, considerable differences were evident in the participation of CRC tests, physician recommendations, and knowledge of, attitudes toward, and barriers to CRC screening. Physician recommendation was the uniform predictor of screening behavior in all countries. Before implementing mass screening programs, improving awareness of CRC and promoting the physicians' role are necessary to increase the screening participation rates.