BackgroundDistinct virulence factors of H. pylori have been described: the vaculating cytotoxin (vacA), the cytotoxin associated gene (cagA), the induced by contact with epithelium factor Antigen (iceA gene) and the outer membrane protein oipA. In Tunisia, there are no data regarding the pattern of H. pylori genotypes; therefore, this prospective and multicentre study was the first to be done in Tunisia and aimed to investigate the prevalence of the vacA, cagA, iceA and oipA genotypes of H. pylori isolates from Tunisian patients with peptic ulceration, gastric cancer, MALT lymphoma and gastritis.MethodsH. pylori was cultured from endoscopic biopsies obtained from 281 Tunisian patients. The vacA alleles, cagA, iceA and oipA genotypes were determined by PCR.ResultsThe vacA s1m1, s1m2 and s2m2 were respectively found in 10.7%, 12.5% and 45.6% of strains. The s2m1 genotype was not detected in our study. The cagA was found in 61.6% of isolates. The iceA1 and the iceA2 genotypes were respectively isolated in 60.2% and in 16% of strains. The oipA genotype was detected in 90.8% of strains. Considering the vacA and iceA genotypes, the presence of multiple H. pylori strains in a single biopsy specimen was found respectively in 31.4% and 23.8%. The comparison between strains isolated from antrum and fundus showed that Tunisian patients were infected with two or more strains of different cagA, vacA, iceA and oipA genotypes and the discordance was respectively in 9.6%, 4.6%, 8.9% and 8.5% of strains.ConclusionOur results showed that in 46% (131 strains among 281), the H. pylori strains were highly virulent in relation of the three or four virulent factors they could carry. These finding were described before in the literature. Tunisian patients were colonized by one or multiple strains of H. pylori in the same time in relation of presence of vacA m1/m2 and iceA1/iceA2 in the same biopsy. The discordance between strains isolated from antrum and fundus was high, and it is in favour of multicolonization.

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BackgroundThe frequency of primary resistance to antibiotics in H. pylori isolates is increasing worldwide. In Tunisia, there are limited data regarding the pattern of H. pylori antibiotic primary resistance.AimTo evaluate the primary resistance of H. pylori to clarithromycin, metronidazole and amoxicillin and to detect the mutations involved in clarithromycin resistance.Materials and methods273 strains isolated from adults and children were enrolled. The primary resistance to clarithromycin, metronidazole and amoxicillin was evaluated by means of E-test minimal inhibitory concentration (MIC). The real-time PCR using Scorpion primers was performed in all cases to assess clarithromycin primary resistance and point mutations involved.ResultsNo resistance to amoxicillin was detected. For adults, resistance to clarithromycin and metronidazole was found respectively in 14.6% and 56.8%, and respectively in 18.8% and 25% in children. Overall, the rates of global primary resistance to clarithromycin and metronidazole in Tunisia were respectively determined in 15.4% and 51.3%.By the use of Scorpion PCR, the A2143G was the most frequent point mutation observed (88.1%), followed by the A2142G (11.9%); the A2142C was not found and 18 of 42 patients (42.8%) were infected by both the resistant and the susceptible genotype.The association of clarithromycin resistance with gender was not statistically significant, but metronidazole resistant strains were isolated more frequently in females (67.8%) than in males (32.2%) and the difference was significant. As for gastroduodenal diseases, the difference between strains isolated from patients with peptic ulceration and those with non peptic ulceration was not statistically significant. When about the distribution of resistant strains to clarithromycin and metronidazole between the three Tunisian cities (Tunis, Menzel Bourguiba and Mahdia), the difference was not statistically significant.ConclusionLocal data regarding the primary resistance of H. pylori to clarithromycin, metronidazole and amoxicillin and the main genetic mutation involved in clarithromycin resistance in vivo (A2143G) are necessary to prove a clear need for a periodic evaluation of antibiotic consumption and new therapeutic strategies in Tunisia in order to avoid the emergence of resistant strains.

In this study, we have attempted to report the first clonal spread of colistin-resistant Klebsiella pneumoniae coproducing KPC and VIM carbapenemases in the neonatal unit of Rabta Teaching Hospital of Tunis (Tunisia). This retrospective study was performed from January 1, 2014 to December 31, 2014 in the Microbiology Laboratory at the Rabta University Hospital of Tunis. Twenty-one nonreplicate colistin-resistant K. pneumoniae were isolated from 19 patients hospitalized in the neonatal unit and 2 patients in the adult intensive care unit (ICU). Most of the strains were isolated from invasive specimens. Pulsed-field gel electrophoresis (PFGE) and PCR analysis and nucleotide sequencing of the blaKPC and blaVIM genes were performed. Mortality was reported in 92% of cases. All the strains were resistant to colistin (minimum inhibitory concentration [MICs] ranged from 8 to 12 mg/L). The MICs for imipenem of K. pneumoniae isolates ranged from 3 to 256 mg/L for 13 strains that were characterized as intermediate or resistant. The MICs for ertapenem were higher than 32 mg/L for the 19 resistant strains. All the isolates were sensitive to tigecycline and chloramphenicol. PFGE analysis revealed two clones (I and II). Twenty of the 21 colistin-resistant, carbapenem-resistant K. pneumoniae isolates belonged to clone I. Only one strain was related to clone II. PCR analysis and nucleotide sequencing revealed that the 20 isolates belonged to clone I, coproduced the blaKPC and blaVIM genes. A single strain (clone II), which was isolated in the ICU, did not produce KPC and VIM carbapenemases. All strains did not produce OXA-48.

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