Imed Cheikh

Primary resistance to clarithromycin, metronidazole and amoxicillin of Helicobacter pylori isolated from Tunisian patients with peptic ulcers and gastritis: a prospective multicentre study

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.

Natural prevalence of hepatitis C virus (HCV) variants resistant to protease and polymerase inhibitors in patients infected with HCV genotype 1 in Tunisia

Hepatitis C virus (HCV) protease inhibitors (PIs) and polymerase inhibitors: nucleos(t)ide inhibitors (NS5B‐NIs) and non‐nucleos(t)ide inhibitors (NS5B‐NNIs) have been recently developed to inhibit protease (NS3) or polymerase (NS5B) activities. The drawback of antiviral treatment is the emergence of resistance mutations to the drugs. The prevalence of such mutations conferring resistance to PIs, NS5B‐NIs, and NS5B‐NNIs before treatment has not been investigated so far in the Tunisian population. The aim of this study was to investigate the prevalence of known substitutions conferring resistance to HCV‐PIs, NS5B‐NIs, and NS5B‐NNIs in 149 untreated patients naïve of any novel or investigational anti‐HCV drugs and infected with HCV genotype 1 (genotype 1a = 7; genotype 1b = 142). Twelve sequences (9.2%) of the 131/149 HCV NS3 sequences analyzed showed amino‐acid substitutions associated with HCV PIs resistance mutations (T54S, n = 4 (3%); V55A, n = 2 (1.5%); Q80K, n = 4 (3%); R155K, n = 1 (0.7%); A156V, n = 1 (0.7%)). One (1%) of the 95/149 HCV NS5B sequences analyzed showed the substitution V321I conferring resistance to NS5B‐NIs, while 34 of 95 (35.8%) showed substitutions conferring resistance to NS5B‐NNIs (C316N, n = 2 (2%); M414L, n = 1 (1%); A421V, n = 8 (8.5%); M423A, n = 1 (1%); M423T, n = 2 (2%); I424V, n = 5 (5.2%); C445F, n = 1 (1%); I482T, n = 2 (2%); V494A, n = 1 (1%); P496A, n = 1 (1%); V499A, n = 15 (16%); S556G, n = 5 (5.2%)). Naturally occurring substitutions conferring resistance to NS3 or NS5B inhibitors exist in a substantial proportion of Tunisian treatment‐naïve patients infected with HCV genotype 1. Their influence on treatment outcome should be assessed. J. Med. Virol. 86:1350–1359, 2014.

Serological and molecular expression of Hepatitis B infection in patients with chronic Hepatitis C from Tunisia, North Africa

BackgroundThis study reports the prevalence and the viral aspects of HBV infection in HCV-positive patients from Tunisia, a country with intermediate and low endemicity for hepatitis B and C, respectively.ResultsHBV infection was assessed in the serum samples of 361 HCV-positive patients and compared to a group of HCV negative individuals. Serological markers were determined by ELISA tests and HBV DNA by real-time PCR. HBV serological markers were found in 43% and 44% of patients and controls, respectively. However, the serological and molecular expression of HBV infection differed in the two groups: The group of patients included more individuals with ongoing HBV infection, as defined by the presence of detectable HBsAg and or HBV DNA (17% and 12%, respectively). Furthermore, while most of the controls with ongoing HBV infection expressed HBsAg, the majority of HCV and HBV positive patients were HBsAg negative and HBV DNA positive. Genotyping of HCV isolates showed large predominance of subtype 1b as previously reported in Tunisia. Comparison of the replicative status of the two viruses found low HBV viral load in all co-infected patients as compared to patients with single HBV infection. In contrast, high levels of HCV viremia levels were observed in most of cases with no difference between the group of co-infected patients and the group with single HCV infection.ConclusionsThis study adds to the knowledge on the prevalence and the virological presentation of HCV/HBV dual infection, providing data from the North African region. It shows that, given the local epidemiology of the two viruses, co-infected patients are likely to have low replication levels of HBV suggesting a suppressive effect of HCV on HBV. In contrast, high replication levels for HCV were fond in most cases which indicate that the presence of circulating HBV-DNA does not necessarily influence HCV replication.

Molecular epidemiology of hepatitis B and Delta virus strains that spread in the Mediterranean North East Coast of Tunisia

BACKGROUND Tunisia is classified as an area of middle endemic for hepatitis B virus (HBV) infection, however little is known about hepatitis Delta virus (HDV) infection. OBJECTIVES This study aimed to address the prevalence of HDV infection, to identify possible risks factors, and to analyze the genetic diversity of HDV strains that are spreading in Tunisia. STUDY DESIGN A retrospective large-scale study including 1615 HBsAg positive patients, native of the North East coast of Tunisia, recruited from Gastroenterology departments, was conducted. Demographic, epidemiological, ethnical, clinical and biological data were recorded. HBV and HDV serological analyses and DNA and RNA viral load quantification were performed. Genotyping of HBV and HDV strains was performed using nucleotide sequencing followed by phylogenetic analyses. RESULTS The study population included 819 (50.7%) men and 796 (49.3%) women; aged 12-90 years (mean age 41±13 years). A very low prevalence of HDV infection, 2% was observed. No risk factor, except a history of hospitalization for surgery was found. All HDV strains belonged to genotype 1, with a wide distribution within the HDV-1 group. They all share the African amino acid marker, a serine at position 202 of the large Delta protein. HBV genotypes were distributed as follows: HBV/D1 (56.8%), HBV/D7 (40.9%), and HBV/A2 (2.3%). CONCLUSION Tunisia is a low endemic region for HDV infection, due to an efficient policy of HBV infection control. HDV-1 is the sole genotype found, with a high diversity within this group. Further studies are ongoing in order to better characterize and manage the HBV/HDV-infected patients according to the genetic variability of the viral strains.

Phylogenetic Analysis and Epidemic History of Hepatitis C Virus Genotype 2 in Tunisia, North Africa

HCV genotype 2 (HCV-2) has a worldwide distribution with prevalence rates that vary from country to country. High genetic diversity and long-term endemicity were suggested in West African countries. A global dispersal of HCV-2 would have occurred during the 20th century, especially in European countries. In Tunisia, genotype 2 was the second prevalent genotype after genotype 1 and most isolates belong to subtypes 2c and 2k. In this study, phylogenetic analyses based on the NS5B genomic sequences of 113 Tunisian HCV isolates from subtypes 2c and 2k were carried out. A Bayesian coalescent-based framework was used to estimate the origin and the spread of these subtypes circulating in Tunisia. Phylogenetic analyses of HCV-2c sequences suggest the absence of country-specific or time-specific variants. In contrast, the phylogenetic grouping of HCV-2k sequences shows the existence of two major genetic clusters that may represent two distinct circulating variants. Coalescent analysis indicated a most recent common ancestor (tMRCA) of Tunisian HCV-2c around 1886 (1869–1902) before the introduction of HCV-2k in 1901 (1867–1931). Our findings suggest that the introduction of HCV-2c in Tunisia is possibly a result of population movements between Tunisia and European population following the French colonization.

Correlation of IFNL4 ss469415590 and IL28B rs12979860 with the hepatitis C virus treatment response among Tunisian patients

A from being an orphanage, Pinnawala, Sri Lanka now is considered as destination for local and international tourists. Out of 88, 5 elephants at Pinnawala had been diagnosed to be having tuberculosis antibodies in their blood possibly due to human elephant interactions. Considering that elephant keepers are at high risk in contacting Tuberclosis (TB), a zoonotic disease, a chest screening program for elephant keepers was held with special emphasis on TB. Preliminary screening was done in February 2017 at Pinnawala, as a mobile chest clinic arranged with Chest Clinic, Kandy in which 121 employees were examined by 3 experienced chest medical officers. They identified one keeper with mMrc score 1. A total of 25 workers including suspected keepers, other workers and veterinary surgeons in Pinnawala who are in close contact with elephants were referred to the chest clinic for further examination. Among such referred individuals, 6 were long time smokers and one keeper had chronic asthma. These individuals were screened under the supervision of a chest consultant, for general respiratory diseases, chest Xrays, Mantoux test and AFB for strongly suspected individuals. Routing chest x-rays and other examinations suggested that all individuals were free from TB and other forms of occupational respiratory diseases. This finding urges a need to question the suspicion in the past of elephant keepers being at high risk to contract TB from elephants in Pinnawela elephant orphanage.