- Volume 60, Issue 7, 2011

Echovirus 6 (E6) and echovirus 11 (E11) are common causes of meningitis and other human diseases; they are among the most frequently isolated enteroviruses worldwide. In the present work we have studied genetic variability over the entire VP1 gene of selected isolates representing a wide geographical and temporal range. Fifty new sequences from North Africa were included, together with previously published sequences from different countries. The sequence diversity between strains of the same type was high: 22 and 30 % for E6 and E11, respectively. Phylogenetic analysis revealed five genogroups within each type, the genetic diversity within a genogroup generally being <20 %. Some genogroups were further subdivided into genotypes, most containing isolates that had circulated over a wide geographical (several countries from different continents) and temporal (up to two decades) range. Several genotypes were also shown to co-circulate in a region during the same period of time. These features differ from other enteroviruses that divide into temporal or geographical clusters. This study reports new sequences from North Africa, updates the molecular epidemiology of E6 and E11, and proposes a new genogroup in each type.

Adhesion of Stenotrophomonas maltophilia, an opportunistic pathogen, to different surfaces has been reported in the literature. However, its ability to adhere to mucus and the involvement of different bacterial appendages in this process has not been elucidated. In this study, bacterial adhesion to mouse tracheal mucus as well as the role of flagella in the adhesion process were investigated using clinical isolates of S. maltophilia. All the clinical isolates adhered to mouse tracheal mucus to varying degrees, showing isolate-to-isolate variation. Isolate Sm2 was selected to study the kinetics of bacterial adhesion to mouse tracheal mucus. The process of bacterial adhesion started after 30 min of incubation, and significant adhesion was detected after 1 h. Bacteria pre-treated with S. maltophilia anti-flagellin antibody were used to determine the role of flagellin in bacterial adhesion. The attachment of S. maltophilia flagellin preparation to mucus was assessed by enzyme immunoassay. Pre-treatment of the bacteria with anti-flagellin antibody resulted in a significant decrease in adhesion to mucus and this decrease was antibody concentration dependent. A similar observation was made when pure flagellin was allowed to interact with mucus. Pre-treatment of mouse tracheal mucus with flagellin led to a significant decrease in bacterial adhesion at concentrations of 40 and 80 µg ml−1 (P<0.05). The ability of S. maltophilia to adhere to mucus was also reduced when mechanically deflagellated bacteria were checked for this property (P<0.005). It was concluded that S. maltophilia has the ability to adhere to mouse tracheal mucus and that flagella play an important role in this process. However, further studies using genetically defined mutants lacking flagella are needed to support this observation.

Erythrasma is a superficial skin disease caused by Gram-positive Corynebacterium species. Coral-red fluorescence under Wood’s light, strongly suggestive of erythrasma, can be attributed to the presence of porphyrins. Fractionated porphyrin analysis in erythrasma lesions is yet to be reported. We attempted to investigate erythrasma lesions by isolating the responsible bacteria and determining their exogenous porphyrin production by HPLC analysis. We observed a 78-year-old woman with erythrasma who had a well-demarcated slightly scaling patch on her left foot, between the fourth and fifth toes. Two kinds of colonies on 5 % sheep blood agar were obtained from this lesion. Analysis of the 16S rRNA sequence revealed the colonies to be Corynebacterium aurimucosum and Microbacterium oxydans. HPLC analysis demonstrated that coproporphyrin III (Copro III) levels were clearly elevated, although the amounts of protoporphyrin were diminished. These results indicate that the fluorescent substance was Copro III. This study supports the view that excess Copro III synthesis by C. aurimucosum and M. oxydans leads to accumulation of porphyrin in cutaneous tissue, which emits a coral-red fluorescence when exposed to Wood’s light.