Antibiotic Resistance Surveillance of Helicobacter Pylori at the Biobío Region (Chile) in a Decade

Abstract

BACKGROUND: Helicobacter pylori infection in Chile remains as a public and private health-care system’s challenge, with a prevalence of the infection over 70%. Nowadays, antibiotic treatment of the infection is mandatory to prevent the arising of severe associated diseases but failures in the eradication therapy mainly due to clarithromycin resistance has been observed worldwide and first line eradication therapy seems to be not effective anymore in several geographical areas. Thus, health-care systems are committed to maintain an epidemiological surveillance upon the evolution of the antibiotic resistance of this priority 2 pathogen. OBJECTIVE: This work reports a 10 years surveillance of the primary antibiotic resistance of H. pylori clinical isolates at the Biobío region-Chile, and the evolution of resistance toward amoxicillin, clarithromycin, levofloxacin, metronidazole, and tetracycline among the species. METHODS: H. pylori strains were investigated during the periods 2005-2007 (1435 patients analysed) and 2015-2017 (220 patients analysed) by inoculating a saline homogenate biopsy onto the surface of Columbia agar (Oxoid, Basingstoke, UK) - supplemented with 7% horse red blood cells plus DENT inhibitor (Oxoid, Basingstoke, UK) - following by incubation at 37ºC under 10% CO2 atmosphere for five days. Antibiotic resistance pattern of the isolates was assessed using the disk diffusion test in Müeller-Hinton agar supplemented with 7% horse red blood cells followed by incubation for further three days under 10% CO2 atmosphere. Statistical analysis was done using the SPSS v22 software and P values <0.05 were considered statistically significant. RESULTS: A total of 41% of 1435 patients were detected to be infected with H. pylori by bacteriological culture in 2005-2007 period, meanwhile 32.7% from 220 patients were also infected in 2015-2017 period. The clinical isolates of H. pylori are mostly susceptible to amoxicillin and tetracycline (both over 98% of strains), but less susceptible to levofloxacin in both periods analysed (over 79% of the strains). On the other hand, metronidazole continuous showing the highest score of resistant isolates (over 40% of resistant strains), although an 18% fewer resistant strains were observed in 2015-2017 period. Clarithromycin, the key antibiotic in eradication therapies, has an increased frequency of resistant strain isolated in the decade (22.5% in 2005-2007 and 29.2% in 2015-2017). Multidrug resistant strains (two, three and four antibiotics) were also detected in both periods with the highest scores for simultaneous resistance to clarithromycin-metronidazole (18%) and clarithromycin-metronidazole-levofloxacin (12.5%) resistant strains. According to gender, the isolates resistant to amoxicillin, clarithromycin and metronidazole were more frequent in female, with a specific increment in amoxicillin and clarithromycin resistance. CONCLUSION: The frequency of clarithromycin resistance (29.2%) detected in 2015-2017 suggests that conventional triple therapy is no longer effective in this region.

Eradication rate and adherence with high‐dose amoxicillin and proton pump inhibitor as first‐line treatment for Helicobacter pylori infection: Experience from University Hospital in Chile

“…The high eradication success rate of HDDT in our study could be attributed to the following factors 1 : in Chile, the rate of resistance to amoxicillin is 4.2%, lower than clarithromycin resistance 21 . In the Eastern Mediterranean and Americas Region, the prevalence of primary amoxicillin resistance was relatively high, accounting for approximately 14% and 10% respectively, 22 this could reduce the efficacy of this therapy in the eradication of H. pylori 2 ; higher dosing frequency of the PPI dose (three times daily) has been associated with longer lasting anti‐acidic effects 23 . H. pylori has been shown to be more sensitive to antibiotics, when the gastric pH value is higher than six 3,24 ; the effect of PPI on inhibiting gastric acid secretion is affected by CYP2C19 gene polymorphism.…”

Consumption of a Gelatin Supplemented with the Probiotic Strain Limosilactobacillus fermentum UCO-979C Prevents Helicobacter pylori Infection in a Young Adult Population Achieved

“…Presently, the antibiotic treatment of infection by H. pylori is mandatory to prevent severe diseases; nevertheless, failures of the eradication therapy, particularly in the case of clarithromycin, have been observed worldwide [ 34 , 35 ]. In this respect, a study by our group indicated that clinical H. pylori isolates obtained in the Bio Bio region (Chile) from 2015 to 2017 were still highly sensitive to amoxicillin and tetracycline, but the resistance frequencies to clarithromycin (29.2%) and levofloxacin (20.8%) [ 36 ] suggested that the conventional triple therapy and therapeutic alternatives may not be effective in the Bio Bio region. A number of therapeutical alternatives have been investigated to prevent or to treat H. pylori infection [ 37 ].…”

Review – Treatment of Helicobacter pylori infection 2020

“…An unprecedented number of studies last year reported on the important topic of antimicrobial resistance of H pylori strains 24‐60 . These are outlined in Table 1.…”