males 25036716 were analyzed for Plasmodium infection by staining with 0.1% mercurochrome to count oocyst numbers. Detection of P. falciparum Ookinetes To determine the number of midgut ookinetes, mosquito midguts were dissected in PBS 20 h post gametocyte feeding. Each gut was suspended in 100 ml of PBS, homogenized gently and 5 ml of the homogenate was spotted on a glass slide and air dried. P. falciparum ookinetes were detected by immunofluorescence as described above using an anti-Pfs25 monoclonal antibody and detected with Rhodamine redTM-X-labeled goat anti-mouse secondary antibody. Bacteria Feeding Bacteria were washed in phosphate buffered saline and suspended in latex feeding buffer at a final concentration of 16106 colony forming units /ml or as indicated. Adult mosquitoes were maintained from the time 27326330 of hatching in sterile 10% sucrose solution containing 10 units/ml penicillin and streptomycin. Antibiotic solution was replaced by sterile sugar solution two days prior to the infectious blood meal. Mosquitoes were starved Acacetin chemical information overnight and fed on medium or bacteria by use of water-jacketed glass-membrane feeders warmed to 37uC. Bacteria suspended in PBS at 106 cfu/ml were injected into the mosquito hemocoel through the thorax. For mixed gametocyte/ bacteria feeding, E. cloacae was washed in ookinete medium RNA Interference A 785 bp region of AgSRPN6 cDNA was amplified using T7-promoter-flanked primers. Double stranded RNA was synthesized using the MEGAscript RNAi kit and purified according to the manufacturer’s Enterobacter-Mediated Refractoriness to Plasmodium instructions. Approximately 300 nl of dsRNA targeting SRPN6 or GFP solution at 3 mg/ml was injected into adult female mosquitoes using a nanojet injector as previously described. Two days later, mosquitoes were fed on a P. falciparum gametocyte culture mixed with E. cloacae. To determine silencing, SRPN6 expression was analyzed by semi-quantitative RT-PCR approximately 6 h after an E. cloacae bacterial meal. during the preparation of this manuscript. We also thank the Malaria Research Institute insect and Parasite Core Facilities for providing mosquitoes and parasite cultures. Support from the Johns Hopkins 
Malaria Research Institute and form the Bloomberg Family Foundation are gratefully acknowledged. ~~ ~~ Since its discovery, there has been a great interest in Staphylococcus aureus isolates related to clonal complex 398, both in terms of epidemiology and diversity of its genomic content. To facilitate rapid detection of S. aureus CC398 isolates, we recently developed a PCR targeting the CC398-specific variant of sau1-hsdS1, a gene encoding the specificity subunit of the S. aureus restriction-modification system Sau1. S. aureus isolates of sequence type 291, have been assumed to be double locus variants of CC398, potentially as a result of a homologue recombination event as indicated by multi locus sequence typing . ST291 has been reported to be sensitive to SmaI digest and thus different from the normal CC398 population by standard pulsed-field gel electrophoresis procedures, and also to exhibit major differences in spa repeats compared to other published CC398-associated spa types. It has also escaped detection by ourCC398 specific PCR. In a recent study using whole genome sequence data to analyze the population structure of CC398, no ST291s were included to give insight into this specific subgroup of CC398. ST291 isolates have been scarcely described in the literature from area