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Dive into the research topics where Olfa Frikha-Gargouri is active.

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Featured researches published by Olfa Frikha-Gargouri.


BMC Microbiology | 2008

Evaluation of an in silico predicted specific and immunogenic antigen from the OmcB protein for the serodiagnosis of Chlamydia trachomatis infections

Olfa Frikha-Gargouri; Radhouane Gdoura; Abir Znazen; Boutheina Gargouri; Jalel Gargouri; Ahmed Rebai; Adnene Hammami

BackgroundThe OmcB protein is one of the most immunogenic proteins in C. trachomatis and C. pneumoniae infections. This protein is highly conserved leading to serum cross reactivity between the various chlamydial species. Since previous studies based on recombinant proteins failed to identify a species specific immune response against the OmcB protein, this study evaluated an in silico predicted specific and immunogenic antigen from the OmcB protein for the serodiagnosis of C. trachomatis infections.ResultsUsing the ClustalW and Antigenic programs, we have selected two predicted specific and immunogenic regions in the OmcB protein: the N-terminal (Nt) region containing three epitopes and the C-terminal (Ct) region containing two epitopes with high scores. These regions were cloned into the PinPoint Xa-1 and pGEX-6P-1 expression vectors, incorporating a biotin purification tag and a glutathione-S-transferase tag, respectively. These regions were then expressed in E. coli. Only the pGEX-6P-1 has been found suitable for serological studies as its tag showed less cross reactivity with human sera and was retained for the evaluation of the selected antigens. Only the Ct region of the protein has been found to be well expressed in E. coli and was evaluated for its ability to be recognized by human sera. 384 sera were tested for the presence of IgG antibodies to C. trachomatis by our in house microimmunofluorescence (MIF) and the developed ELISA test. Using the MIF as the reference method, the developed OmcB Ct ELISA has a high specificity (94.3%) but a low sensitivity (23.9). Our results indicate that the use of the sequence alignment tool might be useful for identifying specific regions in an immunodominant antigen. However, the two epitopes, located in the selected Ct region, of the 24 predicted in the full length OmcB protein account for approximately 25% of the serological response detected by MIF, which limits the use of the developed ELISA test when screening C. trachomatis infections.ConclusionThe developed ELISA test might be used as a confirmatory test to assess the specificity of serological results found by MIF.


BMC Infectious Diseases | 2012

Chlamydia trachomatis genovar distribution in clinical urogenital specimens from Tunisian patients: high prevalence of C. trachomatis genovar E and mixed infections

Houda Gharsallah; Olfa Frikha-Gargouri; Hanen Sellami; Fatma Besbes; Abir Znazen; Adnene Hammami

BackgroundThis epidemiological study was carried out in Sfax (south of Tunisia) and focused on genital Chlamydia trachomatis (C. trachomatis) genovar distribution.MethodsOne hundred and thirty seven genital samples from 4067 patients (4.2%) attending the Habib Bourguiba University hospital of Sfax over 12 years (from 2000 to 2011) were found to be C. trachomatis PCR positive by the Cobas Amplicor system. These samples were genotyped by an in house reverse hybridization method.ResultsOne hundred and eight (78.8%) samples contained only one genovar and 29 (21.2%) samples contained two or three genovars. Genovar E was the most prevalent (70.8%) single genovar and it was detected in 90.6% of all the cases. Genovars J, C and L1-L3 were not detected in our samples whereas ocular genovars A and B were in 5 cases. All the five cases were mixed infections. Men had more mixed infections than women (p=0.02) and were more frequently infected by genovars F and K (p<0.05). No associations between current infection, infertility and the genovar distribution were observed. Patients coinfected with Neisseria gonorrhoeae were also significantly more frequently infected with mixed genovars (p=0.04).ConclusionsIn conclusion, we have reported a high prevalence of genovar E and of mixed infections in our study population. Such data could have implications for the control and vaccine development of C. trachomatis in Tunisia.


Journal of Applied Microbiology | 2015

Bacillus amyloliquefaciens strain 32a as a source of lipopeptides for biocontrol of Agrobacterium tumefaciens strains

D. Ben Abdallah; Olfa Frikha-Gargouri; Slim Tounsi

A Bacillus amyloliquefaciens strain, designated 32a, was used to identify new compounds active against Agrobacterium tumefaciens and to evaluate their efficiency to control crown gall on carrot discs.


Pathologie Biologie | 2008

Usefulness of enzyme linked immunosorbent assays species specific in the detection of Chlamydia trachomatis and Chlamydophila pneumoniae IgG antibodies in patients with genital infections or respiratory tract infections

Olfa Frikha-Gargouri; Abir Znazen; Radhouane Gdoura; B. Gargouri; N. Ben Arab; M. Ben Jemaa; Adnene Hammami

Chlamydia trachomatis (Ct) and Chlamydophila pneumoniae (Cpn) are obligate intracellular bacteria causing genital tract infections (GTI) and respiratory tract infections (RTI), respectively. Antigenic cross-reactivity between the two species may complicate serologic diagnosis. In this study, we compared the performance of two ELISA tests in relation to microimmunofluorescence (MIF) for the detection of Ct and Cpn IgG antibodies. We also explored the degree of cross-reactivity by ELISA and MIF. Among 278 positive sera for Cpn and/or Ct IgG antibodies in the MIF, 153 were from patients with GTI and 125 were from patients with RTI. These sera were tested by our in house MIF test and by two commercial ELISA: SeroCP and SeroCT for the detection of anti-Cpn IgG antibodies and anti-Ct IgG antibodies, respectively. In sera from patients with RTI, correlation between MIF and SeroCP was 92%. The specificity of this test was 38.5%. In fact, among the 140 sera from patients with GTI and that cross-reacted in MIF, only six were confirmed by the two ELISA tests as having IgG antibodies to Ct. The correlation between MIF and SeroCT was 80%. The specificity of this test was 100%. Indeed, among the 65 sera from patients with RTI with cross-reactions in MIF, 30 sera showed a negative SeroCT test. SeroCT was highly specific and could diminish considerably the extent of cross-reactions. Whilst, SeroCP test was not specific enough to distinguish between the presence of IgG antibodies and Cpn or Ct.


Journal of Andrology | 2011

A Proposed Mouse Model to Study Male Infertility Provoked by Genital Serovar E, Chlamydia trachomatis

Hanen Sellami; Radhouane Gdoura; Imed Mabrouk; Olfa Frikha-Gargouri; Leila Keskes; Zohair Mallek; Mahjoub Aouni; Adnane Hammami

Chlamydia trachomatis is a common sexually transmitted pathogen. The impact of chlamydial infection on male infertility is controversial. The aim of this study was to assess the role of C trachomatis human genital serovar E on sperm function, induction of apoptosis in spermatozoa, and reproductive performance, using the Swiss male mice model. Fertile mice were inoculated in the meatus urethra with 10(6) C trachomatis inclusion-forming units at day 0. The studied parameters were evaluated 7, 15, 21, and 30 days postinoculation (pi) in infected and sham-infected controls. Semen parameters of the infected mice groups were significantly lower than those of the control groups at the different days pi. DNA fragmentation study indicated that the mean percentages of apoptotic spermatozoa in the infected mice groups were significantly higher than those in the control groups 7 and 15 days pi, whereas the mean percentages of necrotic spermatozoa in the infected mice groups were significantly higher than those in the control group on the 30th day pi. A decrease in reproductive performance was observed at different days pi in infected male mice groups when compared to the control groups. Furthermore, a statistically significant decrease in the mean number of infant mice was observed at 21 and 30 days pi. In conclusion, our data showed that inoculation of fertile male Swiss mice in the meatus urethra with C trachomatis could lead to alteration of semen parameters, induction of apoptosis in spermatozoa, and decrease of the reproductive performance of male mice.


BMC Infectious Diseases | 2008

Evaluation and optimization of a commercial enzyme linked immunosorbent assay for detection of Chlamydophila pneumoniae IgA antibodies

Olfa Frikha-Gargouri; Radhouane Gdoura; Abir Znazen; Nozha Ben Arab; Jalel Gargouri; Mounir Ben Jemaa; Adnene Hammami

BackgroundSerologic diagnosis of Chlamydophila pneumoniae (Cpn) infection routinely involves assays for the presence of IgG and IgM antibodies to Cpn. Although IgA antibodies to Cpn have been found to be of interest in the diagnosis of chronic infections, their significance in serological diagnosis remains unclear. The microimmunofluorescence (MIF) test is the current method for the measurement of Cpn antibodies. While commercial enzyme linked immunosorbent assays (ELISA) have been developed, they have not been fully validated. We therefore evaluated and optimized a commercial ELISA kit, the SeroCP IgA test, for the detection of Cpn IgA antibodies.MethodsSerum samples from 94 patients with anti-Cpn IgG titers ≥ 256 (study group) and from 100 healthy blood donors (control group) were tested for the presence of IgA antibodies to Cpn, using our in-house MIF test and the SeroCP IgA test. Two graph receiver operating characteristic (TG-ROC) curves were created to optimize the cut off given by the manufacturer.ResultsThe MIF and SeroCP IgA tests detected Cpn IgA antibodies in 72% and 89%, respectively, of sera from the study group, and in 9% and 35%, respectively, of sera from the control group. Using the MIF test as the reference method and the cut-off value of the ELISA test specified by the manufacturer for seropositivity and negativity, the two tests correlated in 76% of the samples, with an agreement of Ƙ = 0.54. When we applied the optimized cut-off value using TG-ROC analysis, 1.65, we observed better concordance (86%) and agreement (0.72) between the MIF and SeroCP IgA tests.ConclusionUse of TG-ROC analysis may help standardize and optimize ELISAs, which are simpler, more objective and less time consuming than the MIF test. Standardization and optimization of commercial ELISA kits may result in better performance.


Diagnostic Microbiology and Infectious Disease | 2009

Diagnostic value of enzyme-linked immunosorbent assays using hypothetical proteins CT226 and CT795 as antigens in Chlamydia trachomatis serodiagnosis

Olfa Frikha-Gargouri; Radhouane Gdoura; Abir Znazen; Jalel Gargouri; Adnene Hammami

The CT226 and the CT795 proteins were produced as purified recombinant proteins and were used as antigens in enzyme-linked immunosorbent assay (ELISA) tests for the detection of Chlamydia trachomatis IgG antibodies. The performances of the developed ELISA tests were compared with our in-house microimmunofluorescence test and the species-specific pELISA test using a panel of 342 sera. Our results indicate that the performance of the CT795 ELISA test was higher than that of the CT226 ELISA test according to the microimmunofluorescence and to the pELISA. To assess whether a combination of tests could improve the serodiagnosis of C. trachomatis infections, we associated results obtained with these tests to that using the previously developed CT694 ELISA test. Combining ELISA test results did not improve significantly the performances of these ELISA tests. The CT795 ELISA test, showing the highest performance, may be used for the serodiagnosis of C. trachomatis infections.


Journal of Applied Microbiology | 2009

Diagnostic value of an enzyme‐linked immunosorbent assay using the recombinant CT694 species‐specific protein of Chlamydia trachomatis

Olfa Frikha-Gargouri; R. Gdoura; Abir Znazen; Jalel Gargouri; A. Rebai; Adnene Hammami

Aim:  To study the performance of the CT694 protein in relation to the microimmunofluorescence (MIF) and the pELISA tests for the serodiagnosis of Chlamydia trachomatis infections.


Journal of Applied Microbiology | 2012

Development and application of an in-house reverse hybridization method for Chlamydia trachomatis genotyping

Houda Gharsallah; Olfa Frikha-Gargouri; F. Besbes; Hanen Sellami; Abir Znazen; Adnene Hammami

To develop and evaluate an in‐house reverse hybridization technique for Chlamydia trachomatis genotype identification.


MicrobiologyOpen | 2018

Comparison of reverse hybridization and ompA sequencing methods applied on Chlamydia trachomatis strains from Tunisia

Houda Gharsallah; Olfa Frikha-Gargouri; Reinier J. M. Bom; Adnene Hammami; S.M. Bruisten

Two techniques based on ompA amplification of Chlamydia trachomatis were compared, being reverse hybridization (RHM) and ompA sequencing (OSA), to investigate the concordance between them and to study the epidemiological relevance of each method. In addition, phylogenetic analysis was performed on the ompA sequences. One hundred and seven C. trachomatis positive samples from Tunisian patients and female sex workers were analyzed using both the RHM and ompA sequencing. The overall genovar distribution obtained with both techniques was very similar. The RHM identified nine genovars, being B, D, E, F, G, H, I, J and K, where B, I, J, and K were only found in mixed infections versus 7 types for the OSA being D, E, F, G, H, I, and K. The agreement between both typing techniques was 87.8%. Both methods showed that genovar E was the most predominant type. In 24.3% of the analyzed samples, mixed infections were detected. In 96.1% of these, the genovar identified by OSA was also detected using the RHM. OmpA sequencing allowed determination of six genovar types that could not be typed using RHM. The analyses of ompA nucleotide variation in the 107 clinical specimens detected ompA genovar variants with distinct ompA mutational patterns for types D2, G1, G2, and H1. In conclusion, RHM and OSA showed a high agreement in C. trachomatis genotyping results with each having their specific benefits.

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