Previous studies have shown an antimalarial effect of total alkaloids extracted from leaves of Guiera senegalensis from Mali in West Africa. We independently observed that the beta-carboline alkaloid harmine obtained from a natural product library screen inhibited Plasmodium falciparum heat shock protein 90 (PfHsp90) ATP-binding domain. In this study, we confirmed harmine-PfHsp90-specific affinity using surface plasmon resonance analysis (dissociation constant [K d ] of 40 M). In contrast, the related compound harmalol bound human Hsp90 (HsHsp90) (K d of 224 M) more tightly than PfHsp90 (K d of 7,010 M). Site-directed mutagenesis revealed that Arg98 in PfHsp90 is essential for harmine selectivity. In keeping with our model indicating that Hsp90 inhibition affords synergistic combinations with existing antimalarials, we demonstrated that harmine potentiates the effect of chloroquine and artemisinin in vitro and in the Plasmodium berghei mouse model. These findings have implications for the development of novel therapeutic combinations that are synergistic with existing antimalarials.

A male patient was admitted to a community hospital in Ontario, Canada, with an infected sacral ulcer after returning from India, where he was hospitalized. Carbapenem-resistant Escherichia coli (isolated from blood cultures), Enterobacter cloacae, and Providencia stuartii (from urine samples), all positive for bla NDM-1 , were recovered. Comparative NDM-1 plasmid analysis suggests both lateral plasmid transfer and independent acquisition of the bla NDM-1 gene in these clinical isolates. Carbapenem resistance in Enterobacteriaceae has emerged worldwide mainly by the production of carbapenemases (1). Carbapenemase genes are commonly carried on conjugative plasmids, representing a significant infection control challenge because of the potential horizontal transfer of resistance genes between bacterial isolates, species, and genera. The New Delhi metallo-␤-lactamase (NDM), first described in 2008 (2), has been detected in different species and genera without a clear link to dominant plasmids or clones (3). In this study, we characterized three different NDM-producing enterobacterial species isolated from the same patient.A 65-year-old man presented to the emergency department of a community hospital in Ontario, Canada, with fever and generalized weakness. He had been hospitalized in India with a urinary tract infection, and his stay was complicated by the development of a large sacral decubitus ulcer. The patient was admitted to the hospital after returning from India with a diagnosis of an infected sacral ulcer. His symptoms improved with the initial treatment (cefazolin and metronidazole), but he had a recurrence of fever. Blood cultures grew Escherichia coli GN568 resistant to all of the antibiotics tested in the hospital except tigecycline, with which the patient was treated for 14 days and recovered. However, 2 weeks after treatment, his fever recurred and blood and urine cultures were collected. His blood cultures grew an extended-spectrum ␤-lactamase (ESBL)-producing Klebsiella pneumoniae strain. His urine grew Enterobacter cloacae GN574 sensitive only to tigecycline and Providencia stuartii GN576 sensitive to tigecycline, trimethoprim-sulfamethoxazole, and ciprofloxacin. The patient was asymptomatic for bacteriuria, and his urinary catheter was changed. He was diagnosed with an infected peripherally inserted central catheter, which was removed, and treated with ertapenem for 14 days against an ESBL-producing, carbapenem-susceptible K. pneumoniae strain detected in blood samples. He recovered from his infections and was discharged to a nursing home. These three carbapenem-resistant clinical isolates (E. coli GN568, E. cloacae GN574, and P. stuartii GN576) were submitted to the Public Health Ontario laboratories for further studies. They were positive for carbapenemase activity by the KPC/MBL Confirm kit (Rosco Diagnostica). They were resistant to all ␤-lactams and aminoglycosides, consistent with the detection of different ␤-lactamase-encoding genes (including bla and bla in two of the isolates, in additio...

Genetic shift because of PCV13 impact may have resulted in the decline of 19A in IPD. Recent rise of serogroup 15 infections in children could be because of its selective advantage conferred by genetic diversity, frequent recombination in the population plus drug resistance potential related to CC63 genotype. Close monitoring of serotype replacement and genetic change in IPD among children post-PCV13 is warranted.

BackgroundClinical observations suggest that Canadian-born (CB) travellers are prone to more severe malaria, characterized by higher parasite density in the blood, and severe symptoms, such as cerebral malaria and renal failure, than foreign-born travellers (FB) from areas of malaria endemicity. It was hypothesized that host cytokine and chemokine responses differ significantly in CB versus FB patients returning with malaria, contributing to the courses of severity. A more detailed understanding of the profiles of cytokines, chemokines, and endothelial activation may be useful in developing biomarkers and novel therapeutic approaches for malaria.Materials and methodsThe patient population for the study (n = 186) was comprised of travellers returning to Toronto, Canada between 2007 and 2011. The patient blood samples’ cytokine, chemokine and angiopoietin concentrations were determined using cytokine multiplex assays, and ELISA assays.ResultsSignificantly higher plasma cytokine levels of IL-12 (p40) were observed in CB compared to FB travellers, while epidermal growth factor (EGF) was observed to be higher in FB than CB travellers. Older travellers (55 years old or greater) with Plasmodium vivax infections had significantly higher mean cytokine levels for IL-6 and macrophage colony-stimulating factor (M-CSF) than other adults with P. vivax (ages 18–55). Patients with P. vivax infections had significantly higher mean cytokine levels for monocyte chemotactic protein-1 (MCP-1), and M-CSF than patients with Plasmodium falciparum. Angiopoietin 2 (Ang-2) was higher for patients infected with P. falciparum than P. vivax, especially when comparing just the FB groups. IL-12 (p40) was higher in FB patients with P. vivax compared to P. falciparum. Il-12 (p40) was also higher in patients infected with P. vivax than those infected with Plasmodium ovale. For patients travelling to West Africa, IFN-γ and IL-6 was lower than for patients who were in other regions of Africa.ConclusionSignificantly higher levels of IL-12 (p40) and lower levels of EGF in CB travellers may serve as useful prognostic markers of disease severity and help guide clinical management upon return. IL-6 and M-CSF in older adults and MCP-1, IL-12 (p40) and M-CSF for P. vivax infected patients may also prove useful in understanding age-associated and species-specific host immune responses, as could the species-specific differences in Ang-2. Regional differences in host immune response to malaria infection within the same species may speak to unique strains circulating in parts of West Africa.