The implementation of real-time PCR for the diagnosis of malaria has been hampered by poor sensitivity for the detection of mixed infections. We have optimized a method that enhances the sensitivity of detection of minor species in mixed infections within a single multiplex reaction. Our assay uses species-specific forward primers in combination with a conserved reverse primer and largely overcomes primer competition for the minor species DNA. With a blind panel of clinical samples, we successfully identified the species in 13/16 mixed infections. This assay was further validated with 91 blood samples and demonstrated a specificity and sensitivity for single infections of 100% compared with nested PCR as the "gold standard." This test has been implemented for routine confirmation of malaria species in Alberta, Canada. In comparison with species identification by microscopy, the real-time PCR test demonstrated greater sensitivity for the identification of species causing low-level and mixed infections and for the discrimination of Plasmodium species other than Plasmodium falciparum. Our experience supports a role for real-time PCR in the identification of malarial species in conjunction with microscopy.

Outpatient FLQ use, ostensibly for community-acquired pneumonia, is not uncommon among patients with pulmonary TB, especially older patients. Single FLQ prescriptions were not associated with FLQ-resistant M. tuberculosis, whereas multiple FLQ prescriptions were associated with FLQ resistance.

Background: A cluster of E. coli O157:H7 hemorrhagic colitis was identified in metro Edmonton, Alberta through notifiable disease surveillance in late 2002. Methods: Environmental health officers collected food histories and clinical information from cases in the cluster. The provincial public health laboratory conducted pulsed field gel electrophoresis (PFGE) analysis on E. coli O157:H7 isolates from cluster cases. Public health and food regulatory agencies conducted an investigation when a food source (unpasteurized gouda cheese) was implicated. Results: PFGE analysis revealed an "outbreak" profile in 13 cases. Onset dates for the outbreak cases ranged between October 2002 and February 2003. Two cases, aged 22 months and 4 years, developed hemolytic uremic syndrome as a result of their infection. Consumption of unpasteurized gouda cheese produced at a local dairy farm was reported by 12 of 13 outbreak cases in the 2 to 8 days prior to illness. E. coli O157:H7 was isolated from 2 of 26 cheese samples manufactured by the implicated producer. The cheese isolates had indistinguishable PFGE profiles as compared with outbreak case isolates. Implicated cheese was found to be contaminated with E. coli O157:H7 104 days after production, despite having met regulated microbiological and aging requirements. Conclusion: To our knowledge, this is the first confirmed outbreak of E. coli O157:H7 infection in Canada associated with raw milk hard cheese. A review of federal legislation vis-à-vis raw milk hard cheese may be in order.

Experience with this postoperative complication is limited, as nontuberculous mycobacteria represent a minority of the pathogens responsible for periprosthetic infections. In the absence of specific features with which to identify patients at risk, the surgeon must be aware of the possibility of this infection. To achieve earlier diagnosis, the clinician should have a high index of suspicion in a patient with delayed onset of symptoms, negative preliminary cultures, and a periprosthetic infection that fails to resolve following a course of conventional antimicrobial treatment. With appropriate treatment, nontuberculous mycobacterial periprosthetic infections can be managed successfully.

How the intracellular parasite Toxoplasma gondii causes placental inflammation and infects the fetus is unknown. By use of a culture model of primary human trophoblasts, we examined the consequences of infection by a virulent strain of T. gondii. Infection fractions (parasitophorous vacuoles per trophoblast nuclei) < or =0.9 were observed 1 day after challenge at an inoculum ratio of T. gondii to nuclei of 10. The culture content of infectious T. gondii increased 45-fold in 48 h. Two days after infection, almost 30% of trophoblast nuclei became apoptotic, and 30%-35% of nuclei were lost. Almost 90% of apoptotic nuclei were not adjacent to a parasitophorous vacuole, suggesting infection protected against apoptosis. However, there was no T. gondii-dependent accumulation of putative cytotoxic factors, such as tumor necrosis factor-alpha, that could mediate paracrine killing. Both mature and immature trophoblasts can be productively infected, and uninfected, but not infected, cells undergo apoptosis.

No abstract

We therefore conclude that in transplant centers with low Toxoplasma seroprevalence, routine screening for Toxoplasma in solid organ donors and recipients is not necessary, particularly in the era of routine TMP/SMX prophylaxis.

The plasmid pVir may play a role in the virulence of Campylobacter jejuni , a leading cause of bacterial gastroenteritis. The pVir plasmid was identified in 17% of 104 C. jejuni clinical isolates studied and was significantly associated with the occurrence of blood in patient stool, a marker of invasive infection. The pVir plasmid was not associated with greater occurrence of diarrhea, fever, pain, vomiting, or need for patient hospitalization. Isolates containing pVir were also associated with the presence of a tetracycline-resistance plasmid, but pVir did not transfer with tetracycline-resistance plasmids to recipient strains of C. jejuni . The association of pVir and bloody stool suggests that pVir may be clinically relevant in C. jejuni infections.