Éva Kocsmár1, Ildikó Kocsmár1, György Miklós Buzás2, Ildikó Szirtes1, Judit Wacha3, Alajos Takáts3, István Hritz3, Matteo Fassan4, Zsuzsa Schaff1, András Kiss1 and Gábor Lotz1
1 2nd Department of Pathology, Semmelweis University, Budapest, Hungary
2 Department of Gastroenterology, Ferencváros Health Centre, Budapest, Hungary
3 1st Department of Surgery, Semmelweis University, Budapest, Hungary
4 Department of Medicine DIMED Pathology and Cytopathology Unit, University of Padova, Padova, Italy.
Bacterial heteroresistance is characterized by simultaneous presence of microbes susceptible and resistant to an antibiotic agent.
Among H. pylori infected patients, several recent studies assessed the prevalence of clarithromycin (Cla) heteroresistance by comparison the resistance status of samples from the antrum and body of stomach. In most of these studies, heteroresistance was diagnosed if antibiotic resistance status differed in antral and corpus biopsy samples and synchronous presence of susceptible and resistant bacteria in the same biopsy sample was not investigated. However, fluorescence in situ hybridization (FISH) technique is capable of visualizing and hereby identifying susceptible and resistant bacteria simultaneously, showing heteroresistant H. pylori populations within one region.
Accordingly, we performed a retrospective study on H. pylori Cla-resistance data obtained by diagnostic FISH method for assessing prevalence of heteroresistance precisely and correlated them with the patients’ anamnestic and clinicopathological data.
Antrum and corpus biopsy specimens of 305 H. pylori positive cases were investigated by a bacterial rRNA- targeted FISH test detecting the Cla-susceptible and -resistant bacteria. Anamnestic data were collected from the institutional electronic register.
Overall resistance rate was reported to be 23.9% (73 cases), consisting of 35 (11.5%) homoresistant and 38 (12.5%) heteroresistant patients.
35 patients had at least one biopsy site where susceptible and resistant bacteria were present simultaneously. Out of this subset, 20 cases had heteroresistant infections on both sites. Prior Cla-based eradication attempts were more frequent in homoresistant than in susceptible and heteroresistant cases (p<.001,p<.001).
Most frequent type of Cla-heteroresistance is simultaneous presence of H. pylori bacteria with different resistance status in the same location. Methods able to detect susceptible and resistant bacteria simultaneously must be used to measure the prevalence of heteroresistance precisely. Previous Cla-based eradication attempt predisposes to homoresistant infection.
Egyedi azonosító: ÚNKP-18-3-I-SE-44
Doctoral School: Pathological Sciences
Program: Alterations of Cells, Fibres and Extracellular Matrix and Diagnostic Pathomorphological Studies in the Course of Heart and Vascular Diseases and in Certain Tumours. Experimental and Diagnostic Pathomorphological Studies
Supervisor: Gabor Lotz
E-mail address: email@example.com