Minimum inhibitory concentrations of commonly used antibiotics against Helicobacter Pylori: A multicenter study in South China

Abstract

Aim To determine the minimum inhibitory concentrations (MICs) of commonly used antibiotics against Helicobacter Pylori (H. pylori) in South China and compare their resistance rates by using EUCAST breakpoints and other breakpoints. Methods Patients who had not previously received H. pylori treatment in clinical centers in South China were enrolled in this study from 2017 to 2020. Gastric biopsies were obtained for H. pylori culture. The MICs of amoxicillin (AMX), clarithromycin (CLA), metronidazole (MTZ), levofloxacin (LEV), tetracycline (TET) and furazolidone (FZD) were tested by broth microdilution method and assessed by two different breakpoints. ATCC43504 standard strain served as a control. Results A total of 208 H. pylori strains were isolated from patients’ biopsy samples. The MICs of AMX, CLA, MTZ, LEV, TET and FZD for H. pylori were 0.0156-256mg/L (MIC50 0.125mg/L, MIC90 4mg/L), 0.0156- >256 mg/L (MIC50 0.0312mg/L, MIC90 64mg/L), 0.0156- >256mg/L (MIC50 8mg/L, MIC90 256mg/L), 0.0156-256mg/L (MIC50 0.25mg/L, MIC90 16mg/L), 0.0156-256mg/L (MIC50 0.0625mg/L, MIC90 4mg/L), and 0.0156- >256mg/L (MIC50 0.0312mg/L, MIC90 2mg/L), respectively. The MICs of AMX, CLA, MTZ, LEV, TET and FZD for ATCC43504 strain were 0.25mg/L, 0.0625mg/L, 64mg/L, 0.5mg/L, 1mg/L and 0.25mg/L, respectively. The resistance rate of FZD was 11.05%. The overall resistance rates according to EUCAST breakpoints and other breakpoints were 57.21% and 14.90% for AMX (p<0.001), 38.94% and 38.94% for CLA (p = 1), 39.42% and 50.96% for MTZ (p<0.001), 12.98% and 10.58% for TET (p = 0.025), 35.10% and 35.10% for LEV (p = 1), respectively. Conclusions Our results demonstrate that AMX, FZD, and TET, but not MTZ, CLR or LEV, showed good anti-H. pylori activity in vitro in South China. When different breakpoints were used, similar results were found with CLA, and LEV, but not with AMX, MTZ, or TET.

Evaluation of Susceptibility of the Human Pathogen Helicobacter pylori to the Antibiotic Capreomycin

“…Formally, we cannot rule out the inclusion of capreomycin-resistant strains in our study as we have also found a noticeable proportion of strains resistant to metronidazole and levofloxacin. In particular, resistance to metronidazole has increased over the past years, while amoxicillin and levofloxacin show generally lower rates of resistance [39][40][41]. We concede that screening a larger number of drug-sensitive strains would be required to assess the levels of resistance to capreomycin, especially in cases where previous antibiotic therapy was applied.…”

Antibiotic susceptibility pattern of Helicobacter pylori against eight antibiotics: A study from North India

“…[ 37 ] This trend might be attributed to the consumption of macrolides and quinolones for other community‐acquired infections. [ 23 ]…”

“…Three microliters of the adjusted inoculum from the BHI broth yielding a viable cell count equivalent to a McFarland four turbidity standard unit was used for spotting on BHI agar plates. [ 11,23,24 ] Additionally, two plates devoid of antibiotics were made as a control for comparative analysis. All plates were incubated for 72 h in a microaerobic environment at 37°C.…”

Drug-Resistant Helicobacter pylori: Diagnosis and Evidence-Based Approach

“…Under microaerophilic circumstances, an E-test strip impregnated with escalating quantities of antibiotics is placed on inoculation plates and incubated for 72 hours at a temperature of 37 • C. The MIC is provided by an elliptical zone of inhibition. When compared to agar dilution or broth dilution procedures, the E-test is straightforward and easy to execute, and it has been found to correlate closely with gold standard (agar dilution) results, except for metronidazole, where recent investigations have revealed some inconsistencies [37][38][39]. The disc diffusion method is a semiquantitative approach to assessing antibiotic resistance.…”