In silico characterisation of putative Plasmodium falciparum vaccine candidates in African malaria populations.

Genetic diversity of surface exposed and stage specific Plasmodium falciparum immunogenic proteins pose a major roadblock to developing an effective malaria vaccine with broad and long-lasting immunity. We conducted a prospective genetic analysis of candidate antigens (msp1, ama1, rh5, eba175, glurp, celtos, csp, lsa3, Pfsea, trap, conserved chrom3, hyp9, hyp10, phistb, surfin8.2, and surfin14.1) for malaria vaccine development on 2375 P. falciparum sequences from 16 African countries. We described signatures of balancing selection inferred from positive values of Tajima's D for all antigens across all populations except for glurp. This could be as a result of immune selection on these antigens as positive Tajima's D values mapped to regions with putative immune epitopes. A less diverse phistb antigen was characterised with a transmembrane domain, glycophosphatidyl anchors between the N and C- terminals, and surface epitopes that could be targets of immune recognition. This study demonstrates the value of population genetic and immunoinformatic analysis for identifying and characterising new putative vaccine candidates towards improving strain transcending immunity, and vaccine efficacy across all endemic populations.

Multidrug-Resistance Genes in Pseudomonas aeruginosa from Wound Infections in a Tertiary Health Institution in Osogbo, Nigeria.

BACKGROUND: Multidrug Resistant Pseudomonas aeruginosa (MDRPA) is a ubiquitous opportunistic organism that poses threat to the management of infections globally. OBJECTIVES: The objectives of the current research were to assess the antibiotic resistance profiles as well as Multiple Antibiotic Resistance (MAR) Index of clinical isolates of P. aeruginosa associated with wound infections. Presence of Extended Spectrum Beta Lactamase genes (bla CTX-M, bla SHV and bla TEM) and Carbapenemase genes (bla KPC and blaNDM) were also determined among the isolates. METHODS: Swab samples were collected from 255 patients with wound infections. Bacterial identification was done by standard diagnostic tests. The identity of isolates was confirmed by the detection of the exoA gene using the PCR technique. Antibiotic susceptibility testing and resistance profile were determined using the disc diffusion method. Resistance genes were amplified by the PCR method. RESULTS: A total of 235 (92.2%) bacterial isolates were recovered from the wounds of the 255 patients, of these, 124 (52.8%) were Gram-negative bacilli while the remaining 111 (47.2%) were Gram-positive cocci. A total of 69 Pseudomonas aeruginosa strains were recovered from the wound specimens. Imipenem was the most effective antibiotic against these isolates (92.8% isolates were susceptible) while all isolates were resistant to Meropenem, Cefepime, Ticarcillin, Amoxicillin-clavulanic acid, Cefotaxime, Ampicillin and Cefpodoxime. All 69 Pseudomonas aeruginosa isolates were multidrug resistant (MDR). Of the isolates selected for PCR, all were positive for TEM, CTX-M and SHV genes while one-third were blaKPC and blaNDM producers. CONCLUSION: This study demonstrated high prevalence of carbapenem-resistant strains of P. aeruginosa, suggesting that there is an urgent need in Nigeria for the enactment and enforcement of policies and necessary laws restricting the availability and indiscriminate use of antibiotics.

Differential effects of methylphenidate and self-reinforcement on attention-deficit hyperactivity disorder.

Six boys aged 9 to 12 years attended a tutoring class focusing on reading for 30 minutes each morning. The investigators employed a modified Latin-square design in which each child began with a 5-day baseline phase followed by six 10-day treatment phases that used drug placebo, noncontingent reinforcers, 0.3 mg/kg methylphenidate, 0.7 mg/kg methylphenidate, and self-reinforcement in various combinations. Amount of academic performance was the major measure of outcome and the target behavior of self-reinforcement. Drug placebo and noncontingent reinforcers had no systematic impact. Methylphenidate had differential effects across the recorded behaviors. Self-reinforcement improved the target behavior; the mean effect size for self-reinforcement was 2.66. The combined effects of methylphenidate and self-reinforcement on academic performance were greater than either of the treatments given alone (mean effect size = 2.89).

Growth of Selected Cross-Contaminating Bacterial Pathogens on Beef and Fish at 15 and 35°C.

Isolates of Escherichia coli and Clostridium perfringens from beef and Aeromonas hydrophila from fish were examined for their ability to survive and grow as cross-contaminates on nonnative tissues at simulated ambient (35°C) and aging/conditioning (15°C) temperatures of handling and retailing found in the tropics. Growth of all isolates over a 10-h period was greater (P < 0.05) on their native tissues at both temperatures. The aging/conditioning temperature effectively limited growth of E. coli and A. hydrophila to less than l-logl0 CFU/g and prevented growth of C. perfringens on beef and fish samples. All three isolates demonstrated characteristic mesophilic growth response on both tissues at 35°C during the 10-h retail period. The study suggests that two muscle food products could be jointly handled to efficiently use available storage/haulage capacity in tropical countries. Potential savings in space, labor and energy would be made if cross-contamination between the two products is minimized by available packaging and sanitizing technologies.

A Simple and Effective Method for Obtaining Aseptic Raw Beef Tissues 1.

The need for gnotoxenic studies (defined microflora) in beef to better understand the microbial ecology of spoilage and pathogenic organisms necessitates the development of a simple and rapid method devoid of obvious disadvantages of existing ones. The aseptic technique described here is an improvement on the flaming and hot-iron searing methods already in use. It involved the use of a Sensa-Temp Heat Control Electric Frier (West Bend, IN) at 232°C to destroy practically all surface microflora on top round meat blocks of freshly slaughtered, healthy beef cattle, before aseptically removing the cooked exterior to a depth of approximately 1 cm. In two separate trials, 95 and 90%, respectively, of the total number of samples removed were sterile. We recommend this method to procure sterile samples suitable for inoculation with defined microflora and for other studies. The method seems applicable to a wide variety of muscle food types, including fish.