The Changing Profile of Helicobacter pylori Antibiotic Resistance in Singapore: A 15-Year Study.

BACKGROUND: Antibiotic resistance is an important cause of H. pylori treatment failure. This study aimed to examine the change in H. pylori antibiotic resistance profile in Singapore over the course of 15 years. MATERIALS AND METHODS: The study period was from 2000 to 2014. Gastric mucosal biopsies obtained from H. pylori-positive patients were cultured. Antibiotic susceptibility to metronidazole, clarithromycin, levofloxacin, tetracycline, and amoxicillin was tested. The change in resistance rates over time was analyzed. RESULTS: A total of 708 H. pylori isolates were cultured. There was a significant increase in resistance rates for metronidazole (2000-2002: 24.8%; 2012-2014: 48.2%; p < .001), clarithromycin (2000-2002: 7.9%; 2012-2014: 17.1%; p = .022), and levofloxacin (2000-2002: 5%; 2012-2014: 14.7%; p = .007). The resistance rates for tetracycline (2000-2002: 5%; 2012-2014: 7.6%) and amoxicillin (2000-2002: 3%; 2012-2014: 4.4%) remained stable. Increase in dual (2000-2002: 6.9%; 2012-2014: 9.4%; p = .479) and triple antibiotic resistance rates (2000-2002: 0; 2012-2014: 7.6%; p < .001) were observed. Overall, the most common dual and triple resistance patterns were metronidazole/clarithromycin (4.4%) and metronidazole/clarithromycin/levofloxacin (1.8%), respectively. CONCLUSIONS: Over 15 years, H. pylori resistance rates to metronidazole, clarithromycin and levofloxacin had increased. There was increased resistance to multiple antibiotics.

Ten-day triple therapy versus sequential therapy versus concomitant therapy as first-line treatment for Helicobacter pylori infection.

BACKGROUND AND AIM: Clarithromycin-based triple therapy (TT) is the first-line treatment for Helicobacter pylori infection in Singapore. There is awareness that TT may no longer be effective due to increased clarithromycin resistance rates. Sequential therapy (ST) and concomitant therapy (CT) are alternative treatment regimens. This study aimed to compare the efficacy of 10-day TT, ST, and CT as first-line treatment for H. pylori infection. METHODS: A randomized study conducted in a teaching hospital. Patients aged 21 years and older with newly diagnosed H. pylori infection were randomized to 10-day TT, ST, or CT. Treatment outcome was assessed by 13-carbon urea breath test at least 4 weeks after therapy. Intention to treat (ITT), modified ITT (MITT), and per protocol (PP) analyses of the eradication rates were performed. RESULTS: A total of 462 patients were enrolled (ST: 154; TT 155; CT 153). Patient demographics were similar. Eradication rates for ST versus TT versus CT: ITT analysis: 84.4% versus 83.2% versus 81.7% (P = not significant [NS]); MITT analysis: 90.3% versus 92.1% versus 94.7% (P = NS); PP analysis: 94.1% versus 92.8% versus 95.4% (P = NS). Antibiotic resistance rates for amoxicillin, clarithromycin, and metronidazole were 4.7%, 17.9%, and 48.1%, respectively. Dual clarithromycin and metronidazole resistance occurred in 7.5%. Dual resistance and lack of compliance were predictors of treatment failure. CONCLUSIONS: TT, ST, and CT all achieved eradication rates above 80% on ITT and above 90% on MITT and PP analyses. Dual resistance and lack of compliance were predictors of treatment failure (clinicaltrials.gov: NCT02092506).

Exercise-Induced Weight Loss is More Effective than Dieting for Improving Adipokine Profile, Insulin Resistance, and Inflammation in Obese Men.

The adipokines chemerin and adiponectin are reciprocally related in the pathogenesis of insulin resistance and inflammation in obesity. Weight loss increases adiponectin and reduces chemerin, insulin resistance, and inflammation, but the effects of caloric restriction and physical activity are difficult to separate in combined lifestyle modification. We compared effects of diet- or exercise-induced weight loss on chemerin, adiponectin, insulin resistance, and inflammation in obese men. Eighty abdominally obese Asian men (body mass index [BMI] ≥ 30 kg/m(2), waist circumference [WC] ≥ 90 cm, mean age 42.6 years) were randomized to reduce daily intake by ~500 kilocalories (n = 40) or perform moderate-intensity aerobic and resistance exercise (200-300 min/week) (n = 40) to increase energy expenditure by a similar amount for 24 weeks. The diet and exercise groups had similar decreases in energy deficit (-456 ± 338 vs. -455 ± 315 kcal/day), weight (-3.6 ± 3.4 vs. -3.3 ± 4.6 kg), and WC (-3.4 ± 4.4 vs. -3.6 ± 3.2 cm). The exercise group demonstrated greater reductions in fat mass (-3.9 ± 3.5 vs. -2.7 ± 5.3 kg), serum chemerin (-9.7 ± 11.1 vs. -4.3 ± 12.4 ng/ml), the inflammatory marker high-sensitivity C-reactive protein (-2.11 ± 3.13 vs. -1.49 ± 3.08 mg/L), and insulin resistance as measured by homeostatic model assessment (-2.45 ± 1.88 vs. -1.38 ± 3.77). Serum adiponectin increased only in the exercise group. Exercise-induced fat mass loss was more effective than dieting for improving adipokine profile, insulin resistance, and systemic inflammation in obese men, underscoring metabolic benefits of increased physical activity.

Distinct cagA EPIYA motifs are associated with ethnic diversity in Malaysia and Singapore.

BACKGROUND: In vitro studies have shown that the biologic activity of CagA is influenced by the number and class of EPIYA motifs present in its variable region as these motifs correspond to the CagA phosphorylation sites. It has been hypothesized that strains possessing specific combinations of these motifs may be responsible for gastric cancer development. This study investigated the prevalence of cagA and the EPIYA motifs with regard to number, class, and patterns in strains from the three major ethnic groups within the Malaysian and Singaporean populations in relation to disease development. MATERIALS AND METHODS: Helicobacter pylori isolates from 49 Chinese, 43 Indian, and 14 Malay patients with functional dyspepsia (FD) and 21 gastric cancer (GC) cases were analyzed using polymerase chain reaction for the presence of cagA and the number, type, and pattern of EPIYA motifs. Additionally, the EPIYA motifs of 47 isolates were sequenced. RESULTS: All 126 isolates possessed cagA, with the majority encoding EPIYA-A (97.6%) and all encoding EPIYA-B. However, while the cagA of 93.0% of Indian FD isolates encoded EPIYA-C as the third motif, 91.8% of Chinese FD isolates and 81.7% of Chinese GC isolates encoded EPIYA-D (p < .001). Of Malay FD isolates, 61.5% and 38.5% possessed EPIYA-C and EPIYA-D, respectively. The majority of isolates possessed three EPIYA motifs; however, Indian isolates were significantly more likely to have four or more (p < .05). CONCLUSION: Although, H. pylori strains with distinct cagA-types are circulating within the primary ethnic groups resident in Malaysia and Singapore, these genotypes appear unassociated with the development of GC in the ethnic Chinese population. The phenomenon of distinct strains circulating within different ethnic groups, in combination with host and certain environmental factors, may help to explain the rates of GC development in Malaysia.

The prevalence of the duodenal ulcer promoting gene (dupA) in Helicobacter pylori isolates varies by ethnic group and is not universally associated with disease development: a case-control study.

BACKGROUND: The putative H. pylori pathogenicity-associated factor dupA has been associated with IL-8 induction in vitro, and duodenal ulcer (DU) and gastric cancer (GC) development in certain populations, but this association is inconsistent between studies. We aimed to investigate dupA prevalence in clinical isolates from Sweden, Australia and from ethnic Chinese, Indians and Malays resident in Malaysia and Singapore and to examine the association with DU and GC. In addition we investigated the sequence diversity between isolates from these diverse groups and compared the level of IL-8 secretion in isolates possessing and lacking dupA. METHODS: PCR primers were designed to amplify over the C/T insertion denoting a continuous dupA. PCR products from 29 clinical isolates were sequenced and compared with sequences from three additional strains obtained from GenBank. Clinical isolates from 21 Malaysian patients (8 dupA-positive, 14 dupA-negative) were assessed for their ability to induce IL-8 in AGS cells in vitro. Statistical analysis was performed using Fisher's exact test. RESULTS: The prevalence of dupA in isolates from Swedish functional dyspepsia (FD) control patients (65%, 13/20) was higher and in isolates from Indian FD patients (7.1%, 3/42) was lower as compared with isolates from Chinese (28.9%, 13/49, P = 0.005, P = 0.025), Malay (35.7%, 5/14, P = 0.16, P = 0.018) and Australian (37.8%, 17/45, P = 0.060, P < 0.001) FD patients. dupA was associated with DU and GC development in Chinese with 62.5% (10/16) and 54.6% (12/22) of isolates possessing dupA respectively as compared with FD controls (28.9%) (P = 0.015, P = 0.032). No significant difference in prevalence of dupA between FD controls, DU (63.6%, 7/11) and GC (61.9%, 13/21) cases (P = 1.000) was observed in the Swedish population. Sequence analysis revealed a pairwise variation of 1.9% and all isolates possessed the C/T insertion. The average IL-8 induction was 1330 pg/mL for dupA-positive isolates and 1378 pg/mL for dupA-negative isolates. CONCLUSION: Although dupA is highly conserved when present, we identified no consistent association between dupA and DU or GC development across the ethnic groups investigated, with the dupA prevalence in control groups varying significantly. Our results would suggest that in the clinical isolates investigated dupA is not associated with IL-8 induction in vitro.

Racial differences in Helicobacter pylori, serum pepsinogen and gastric cancer incidence in an urban Asian population.

BACKGROUND: In Singapore, the highest incidence of gastric cancer occurs in the Chinese (C), with lower rates among Malay (M) and Indian (I) subjects. The purpose of the present paper was to examine whether racial differences in the prevalence of Helicobacter pylori and serum pepsinogen (PG) could account for this difference. METHODS: A randomized community health survey involving 7000 asymptomatic healthy individuals was conducted. Among the Chinese, Malay and Indian respondents, subjects were matched for age, gender and race and a total of 595 sera were obtained. The H. pylori seropositivity and serum PG levels were determined by ELISA. The dependency of the cumulative gastric incidence rate on H. pylori seroprevalence was evaluated by linear regression. The racial difference in the seroprevalence of H. pylori and low serum PG was determined. RESULTS: The H. pylori seroprevalence was similar between Chinese and Indian subjects, but significantly lower among Malay subjects (C, 46.3%; M, 27.9%; I, 48.1%). The gastric cancer incidence rates correlated with H. pylori seropositivity for the Chinese and Malay subjects, but not for the Indian subjects. The prevalence of low PG was highest in Indian subjects (PG I low: C, 2.1%; M, 5.4%; I, 14.2%; P < 0.0001; PG I:II ratio low: C, 5.3%; M, 5.9%; I, 12.6%; P = 0.012), even when adjusted for gender and the presence of H. pylori. CONCLUSIONS: The difference in gastric cancer incidence correlated with H. pylori seroprevalence for Chinese and Malay subjects. The lower incidence of gastric cancer among Indian subjects cannot be explained by differences in H. pylori or serum PG. Other modifying factors such as host and environmental factors may be important.

Seroreactivity to 19.5-kDa antigen in combination with absence of seroreactivity to 35-kDa antigen is associated with an increased risk of gastric adenocarcinoma.

BACKGROUND: Only a minority of those infected with Helicobacter pylori will develop gastric cancer. Stratification of H. pylori strains based on carcinogenic potential will provide a basis for selective surveillance and eradication therapy. We studied the anti-H. pylori antibody profile in Asian patients with gastric adenocarcinoma to identify any H. pylori antigen that may be associated with an increased or decreased risk of gastric carcinoma. PATIENTS AND METHODS: A case-control study comparing the seroprevalence of antibodies with various H. pylori antigens in Singaporeans with gastric adenocarcinoma and the normal Singaporean population was carried out using both conventional immunoglobulin (Ig) G enzyme-linked immunosorbent assay (ELISA) and Western blot immunoassay. RESULTS: The seroprevalence among 44 gastric adenocarcinoma cases (70.5% males, mean age 66.7 +/- 13.5 years) and 261 controls (49.8% males, mean age 61.5 +/- 4.1 years) was 90.9% vs. 50.2% by IgG ELISA. In the H. pylori-positive male population, those suffering from gastric adenocarcinoma had significantly lower seroreactivity to the 35-kDa antigen compared with asymptomatic controls (p =.0198, OR = 3.79, 95% CI 1.24-11.61). Seropositivity to the 19.5 kDa antigen was also found to be associated with the presence of gastric adenocarcinoma in Singaporean males (p =.022, OR = 4.17, 95% CI 1.22-14.28). A 'high-risk' phenotype consisting of absence of a band at 35-kDa in combination with the presence of a band at 19.5-kDa was significantly associated with the presence of gastric adenocarcinoma (p =.002, OR = 3.7, 95% CI 1.6-8.6). CONCLUSIONS: Stratification of H. pylori strains based on their potential for carcinogenesis, such as those strains that are seropositive for the 19.5 kDa antigen and seronegative for the 35-kDa antigen, may provide a basis for selective eradication of H. pylori infection and future vaccine development.