Antimicrobial susceptibility of Helicobacter pylori strains isolated from children in Israel.

OBJECTIVES: Helicobacter pylori is a bacterial pathogen causing inflammation of the gastric mucosa that may lead to peptic ulcer, perforation or malignancy. Children are at risk of contracting H. pylori and developing subsequent morbidity. Diagnosis and management in children are difficult and merit a different approach compared with adults. This study aimed to describe the antimicrobial resistance rates of H. pylori to amoxicillin, tetracycline, clarithromycin, metronidazole, levofloxacin and rifampicin. METHODS: Biopsies (n=154) collected during endoscopic examinations were cultivated for 10days using a growth medium selective for H. pylori, of which 89 were H. pylori-positive. Antimicrobial resistance of the strains was assessed by Etest to establish minimum inhibitory concentrations (MICs) according to British Society for Antimicrobial Chemotherapy guidelines. RESULTS: Resistance rates were most notable for amoxicillin and clarithromycin at 12% and 35% with MICs of 0.74µg/mL and 2.51µg/mL, respectively. Resistance rates to tetracycline and levofloxacin were 8% and 2% with MICs of 2.57µg/mL and 2.0µg/mL, respectively. Resistance rates to rifampicin and metronidazole were 3% and 8% with MICs of 2.0µg/mL and 9.71µg/mL, respectively. CONCLUSION: Current rising antibiotic resistance rates for H. pylori are of concern. Performance of culture enables determination of the susceptibility profile, which may lead to a better choice of, and perhaps narrower spectrum, antibiotic agent. In light of these findings, we suggest that optimising the choice of antibiotic agent in children with H. pylori infection remains a challenge for clinicians and thus requires further investigation in randomised clinical trials.

Efficacy of an Enrichment Media for Increasing Threshold for Carbapenem-Resistant Enterobacteriaceae Screening.

BACKGROUND: Identification of carbapenem-resistant Enterobacteriaceae (CRE) is complex and a major laboratory challenge; clinical cultures may diagnose only some of the CRE carriers among patients, thus it is crucial to perform asymptomatic carriage screening. MATERIALS AND METHODS:  We compare the efficacy of a rectal sample culture prior to enrichment with BHI (Brain Heart Infusion) Broth and following 18-24 h. All rectal samples were applied on CHROMagar KPC selective growth media and then seeded on MacConkey agar selective growth media with an applied disk of Imipenem antibiotic on top of the media, then inserted into enrichment BHI Broth. After 18-24 h incubation with enrichment media, all samples were applied again on this media. RESULTS: From the 2,245 rectal samples, CRE colonies were found in 96 (4.3%). Following enrichment with BHI Broth, CRE colonies were found in 111 (4.9%) CHROMagar KPC plates and 106 (4.7%) MacConkey agar. CONCLUSION: We were able to demonstrate that the number of CRE-positive results increased due to use of additional enrichment with BHI Broth. Therefore, we recommend applying this method of addition of liquid enrichment media as part of a culture protocol routine for CRE screening.

An efficiency comparison between three invasive methods for the diagnosis of Helicobacter pylori infections: Culture from stomach biopsy, rapid urease test (CUTest(®)), and histologic examination of gastric biopsy.

BACKGROUND: Helicobacter pylori is one of the most prevalent pathogenic bacteria in the world, and humans are its principal reservoir. There are several available methods to diagnose H. pylori infection. Disagreement exists as to the best and most efficient method for diagnosis. METHODS: In this paper, we report the results of a comparison between three invasive methods for H. pylori diagnosis among 193 patients: culture, biopsy for histologic examination, and rapid urease test (CUTest(®)). RESULTS: We found that all three methods have a high sensitivity and specificity for the diagnosis of infections caused by H. pylori. However, the culture method, which is not used routinely, also showed high sensitivity, probably due to biopsies' seeding within 30 minutes, using warm culture media, non-selective media, and longer incubation. CONCLUSIONS: Although not a routine test, culture from biopsy can be meaningful in identification of antibiotic-resistant strains of H. pylori and should therefore be considered a useful diagnostic tool.