A phenotypic and molecular investigation of biofilm formation in clinical samples of Pseudomonas aeruginosa

Pseudomonas aeruginosa is identified as a versatile opportunistic microorganism with metabolic diversity contributing to a wide range of health burdens, especially in immunocompromised patients. This bacterium is the cause of 10 to 20% of nosocomial infections. In this study, we evaluated the phenotypic characterizations of biofilm formation in P. aeruginosa clinical isolates using micro-titer plate assay. Indeed, we estimated the prevalence of QS (rhlI, rhlR, rhlAB, lasB, lasI, lasR, aprA) and virulence genes (pslA and cupA) by PCR. The results showed that among 69% of the isolates forming biofilm, 9% were strong biofilm producers, whereas 13% and 47% of isolates produced moderate and low amounts of biofilm, respectively. All isolates possessed cupA and seven QS genes (rhlI, rhlR, rhlAB, lasB,  lasI, lasR, aprA), while 92% of the isolates possessed the pslA gene. Identification of these genes and their association with biofilm formation can be advantageous in adopting therapeutic methods.

A comparison of multivalent and bivalent vaccination strategies for the control of virulent ovine footrot

Virulent footrot is a significant economic and animal welfare concern. The disease can be treated, controlled, and eliminated with vaccine, but selecting the appropriate vaccination strategy can be challenging. There are two main strategies: outbreak (serogroup)-specific univalent or bivalent vaccination, or use of a multivalent vaccine containing up to nine of the most common serogroups. The objective of this study was to compare these approaches in sheep flocks infected with multiple Dichelobacter nodosus serogroups. In the first phase, we undertook an immunogenicity trial in which we compared four pre-commercial multivalent recombinant fimbrial vaccines containing six (A, B, C, G, H, I) or nine (A, B, C, D, E, F, G, H, I) serogroups, and compared them to commercial bivalent vaccines. Two multivalent vaccines stimulated significantly higher antibody responses than two other multivalent vaccines but the number of serogroups included in the multivalent vaccine formulations did not have a significant effect. In the first phase, we also compared inter-vaccination intervals of two- and three-months between sequential bivalent vaccines, and found that a two-month interval was sufficient to avoid antigenic competition. In the second phase, the most immunogenic multivalent vaccine (nine serogroups) was compared to sequential bivalent vaccines and monthly foot-bathing in a field trial in four commercial Merino flocks. The duration of protection afforded by the multivalent vaccine was likely to be less than that of the bivalent vaccines, as the antibody titres stimulated were lower and less persistent.

Fimbrial dermoid cyst with elevated CA19-9 levels: A case report

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Dermoid cysts in aberrant locations are usually reported at Caesarean section or during laparoscopic sterilisation and thus a pre-operative CA19-9 level is rarely available.

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That and the rarity of these 'ectopic dermoids' make it very hard to give further support to a causative association with the high tumour marker levels.

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We report the case of a 39-year-old woman who presented in an acute setting with pelvic pain and was found to have a large dermoid cyst located at the fimbrial end of the left fallopian tube with no apparent connection to either ovary.

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It has been suggested that auto-amputation of a dermoid cyst or part thereof and subsequent reimplantation could give rise to this phenomenon, and this is what we postulated as the cause in our case.

We report the case of a 39-year-old woman who presented in an acute setting with pelvic pain, an adnexal mass on imaging and a high CA19-9 level. She was taken for surgery, where a large dermoid cyst was found at the fimbrial end of a fallopian tube at the time of laparoscopy, with no apparent connection to either ovary and absence of ovarian necrosis. This was corroborated on final histology. Dermoid cysts in aberrant locations are usually reported at Caesarean section or during laparoscopic sterilisation and thus, understandably, a pre-operative CA19-9 level is rarely available. That and the rarity of these 'ectopic dermoids' make it hard to give further support for a causative association with the high tumour marker levels. Some authors suggest that auto-amputation of a dermoid cyst or part thereof and subsequent reimplantation may give rise to this phenomenon, and thus the term 'wandering dermoid' has been applied to similar situations. This is what we postulated as the cause in our case. It is likely that a full understanding of the aetiology of wandering dermoid cysts will remain elusive, given the paucity of cases.

The major fimbrial subunit protein of Edwardsiella tarda: vaccine potential, adjuvant effect, and involvement in host infection

Edwardsiella tarda is a Gram-negative bacterium that is reckoned one of the most severe fish pathogens. In this study, we analyzed the biological properties of the E. tarda major fimbrial subunit protein, FimA. We found that mutation of fimA resulted in defective biofilm growth, attenuated infectivity against host cells, and impaired ability to disseminate into and colonize host tissues following experimental infection. When used as a subunit vaccine, recombinant FimA (rFimA) elicited a high level of protection in turbot (Scophthalmus maximus) against lethal E. tarda challenge. Immunological analysis showed that rFimA vaccination induced production of specific serum antibodies that bound to live E. tarda via interaction with the FimA on bacterial cells, and that antibody-E. tarda interaction blocked bacterial infection. Furthermore, passive immunization of turbot with anti-rFimA serum before E. tarda infection reduced bacterial loads in fish tissues to significant extents. To examine the adjuvant potential of FimA, turbot were vaccinated with rVhhP2, a protective Vibrio harveyi antigen, in the presence or absence of rFimA. Subsequent analysis showed that the presence of rFimA significantly augmented the protectivity of rVhhP2. ELISA and quantitative real time RT-PCR showed that rFimA significantly increased rVhhP2-specific serum antibody production and enhanced the expression of immune relevant genes. Taken together, these results indicate that FimA is a virulence-associated protein that possesses vaccine as well as adjuvant potentials, and that the immunoprotectivity of FimA is most likely due to its ability to induce specific immune response that inhibits E. tarda infection.