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Accurate identification of Mitis group streptococci especially Streptococcus pneumoniae and Streptococcus pseudopneumoniae seems difficult due to the lack of specific and sensitive tests. We performed an approach for the identification of atypical pneumococci in pediatric Tunisian population. In this study, 49 streptococcal isolates that were considered as atypical S. pneumoniae were analyzed by: optochin susceptibility in ambient and 5% CO2 atmosphere, oxgall disk sensitivity, PCR targeting several genes and antimicrobial susceptibility. The combined results of biochemical and molecular methods showed the presence of 23 S. pneumoniae , 7 S. pseudopneumoniae , and 19 other mitis group. Among S. pseudopneumoniae , all isolates were collected from respiratory tract samples and showed a high level of resistance to β-lactams with a MIC90 of 32 mg L−1. Two isolates of S. pseudopneumoniae showed the typical phenotype of optochin resistance described in the literature. All isolates could be identified only by molecular tests. Among Streptococcus pneumonaie , all strains harbored the lytA gene and the Spn9802 fragment. But only 14 strains were encapsulated. This study describes several assays for the identification of atypical pneumococci in order to gain insights on the nature of isolate and raise alert about the presence of these strains in the pediatric Tunisian community. [ABSTRACT FROM AUTHOR]

Free-range chickens are infected by Toxoplasma gondii (T. gondii) mainly when they pick-up their food from the ground. The present study was performed to estimate the molecular prevalence of T. gondii in free-range chicken meat (breast and thigh muscles) and their offal (heart and gizzard). The molecular characterization and the phylogeny of T. gondii amplicons were also investigated. Two PCRs were compared, the first targeting B1 gene and a nested PCR targeting the internal transcribed spacer ITS-1 gene. Among the 60 tested birds, 47 free-range chickens had at least one positive PCR, i.e., a prevalence of 78.3% (95% CI: 67.9–88.7%). The prevalence of T. gondii infection in muscles and organs analyzed by specific PCR targeting B1 gene (43.3%; 95% CI: 37–49.6%) was significantly higher than those analyzed for ITS-1 gene detection (15%; 95%CI: 10.4–19.5%) (p < 0.001). Heart samples had the highest T. gondii infection prevalence, as well as targeting either B1 gene (48.3%; 95% CI: 35.6–60.9%) or ITS-1 gene (21.6%; 95% CI: 11.2–32%). The present study showed that the consumption of undercooked free-range chicken meat represents a high risk for seronegative pregnant women. Our phylogenetic analysis revealed homology with wild and domestic birds and domestic mammals and a large geographic distribution. [ABSTRACT FROM AUTHOR]

Introduction: Streptococcus pneumoniae can be responsible for severe human infections. Optochin resistance has been a potential cause of misidentification of pneumococcus and other members of the mitis group. Hence, rapid and easy optochin resistant (Optr) S. pneumoniae identification is essential. Methodology: Atypical pneumococci were characterized using optochin susceptibility, bile solubility based on spectrophotometric reading, serotyping, pulsed field gel electrophoresis (PFGE), 16S rRNA sequencing and PCR-based assays targeting pneumococcal genes lytA, ply, pspA, cpsA, Spn9802 and Spn9828. Results: Optical density values for the bile solubility test suggest the identification of four Optr S. pneumoniae and one Streptococcus pseudopneumoniae. All Optr pneumococci harbored cpsA, lytA, ply, Spn9802, Spn9828 and pspA genes. Only ply, spn9802 and Spn9828 genes were detected in S. pseudopneumoniae. The 16S rRNA sequencing differentiates between these two species. Optr S. pneumoniae strains belonged to different genotypes and serotypes (14, 19A, 3 and 9V). Three Optr S. pneumoniae isolates were typed as pspA family 2, while one belonged to pspA family 1. Sequencing of the atpA and atpC gene of the Optr variants revealed three mutations in the ATPase a-subunit (L99I, M23V and V52I) and one mutation in ATPase c-subunit (V48I). Conclusions: Our data indicate that bile OD-values provides an accurate, fast and easy method to discriminate between Optr S. pneumoniae and other Streptococcus mitis group. Moreover molecular techniques, confirming the bile test, can be used in order to prevent these atypical pneumococci and alert clinical microbiologists of the presence of these strains in the community. [ABSTRACT FROM AUTHOR]

Abstract: Fifty two isolates of Mycosphaerella graminicola from Tunisia were analysed for their sensitivity to pyraclostrobin and epoxiconazole in microtitre tests and for mutations in the target genes of the modes of action, cytochrome b and CYP51, respectively. All isolates were highly sensitive to pyraclostrobin, thus no isolate carried the G143A mutation in the cytochrome b gene, the mutation which is the proved mechanism in M. graminicola for QoI resistance. The Tunisian M. graminicola population was more sensitive to epoxiconazole when compared with European populations based on previously published data. However, some mutations in the CYP51, which are known to be an adaptation response to DMIs have been found in a part of the population (e.g. mutations A379G, I381V), but there is still a portion with wild type isolates, which has already disappeared in Northern Europe. The current data indicate a favourable situation for QoI and DMI sensitivity, but it should be considered in any disease management strategy to include different modes of action to avoid QoI resistance and further adaptation to DMIs. [Copyright &y& Elsevier]