Analysis of antimicrobial susceptibility and virulence factors in <it>Helicobacter pylori </it>clinical isolates

• Main Authors: Mendonça Sergio, Miranda Maira de Carvalho, Vitiello Lea, Benvengo Yune, Ribeiro Marcelo, Godoy Anita, Pedrazzoli José
• Format: Article
• Language: English
• Published: BMC 2003-08-01
• Series: BMC Gastroenterology
• Online Access: http://www.biomedcentral.com/1471-230X/3/20

<p>Abstract</p> <p>Background</p> <p>In this study, we evaluated the prevalence of primary resistance of Brazilian <it>H. pylori </it>isolates to metronidazole, clarithromycin, amoxicillin, tetracycline, and furazolidone. In addition, the <it>vac</it>A, <it>ice</it>A, <it>cag</it>A and <it>cag</it>E genotypes of strains isolated from Brazilian patients were determined and associated with clinical data in an effort to correlate these four virulence markers and antibiotic resistance.</p> <p>Methods</p> <p><it>H. pylori </it>was cultured in 155 <it>H. pylori</it>-positive patients and MICs for metronidazole, clarithromycin, amoxicillin, tetracycline, and furazolidone were determined by the agar dilution method. Genomic DNA was extracted, and allelic variants of <it>vacA</it>, <it>iceA</it>, <it>cagA </it>and <it>cagE </it>were identified by the polymerase chain reaction.</p> <p>Results</p> <p>There was a strong association between the <it>vacA </it>s1/<it>cagA </it>-positive genotype and peptic ulcer disease (OR = 5.42, 95% CI 2.6–11.3, p = 0.0006). Additionally, infection by more virulent strains may protect against GERD, since logistic regression showed a negative association between the more virulent strain, <it>vac</it>A s1/<it>cag</it>A-positive genotype and GERD (OR = 0.26, 95% CI 0.08–0.8, p = 0.03). Resistance to metronidazole was detected in 75 patients (55%), to amoxicillin in 54 individuals (38%), to clarithromycin in 23 patients (16%), to tetracycline in 13 patients (9%), and to furazolidone in 19 individuals (13%). No significant correlation between pathogenicity and resistance or susceptibility was detected when MIC values for each antibiotic were compared with different <it>vacA</it>, <it>iceA</it>, <it>cagA </it>and <it>cagE </it>genotypes.</p> <p>Conclusion</p> <p>The analysis of virulence genes revealed a specific association between <it>H. pylori </it>strains and clinical outcome, furthermore, no significant association was detected among pathogenicity and resistance or susceptibility.</p>