BackgroundRecent research has demonstrated that many swine and swine farmers in the Netherlands and Canada are colonized with MRSA. However, no studies to date have investigated carriage of MRSA among swine and swine farmers in the United States (U.S.).MethodsWe sampled the nares of 299 swine and 20 workers from two different production systems in Iowa and Illinois, comprising approximately 87,000 live animals. MRSA isolates were typed by pulsed field gel electrophoresis (PFGE) using SmaI and EagI restriction enzymes, and by multi locus sequence typing (MLST). PCR was used to determine SCCmec type and presence of the pvl gene.ResultsIn this pilot study, overall MRSA prevalence in swine was 49% (147/299) and 45% (9/20) in workers. The prevalence of MRSA carriage among production system A's swine varied by age, ranging from 36% (11/30) in adult swine to 100% (60/60) of animals aged 9 and 12 weeks. The prevalence among production system A's workers was 64% (9/14). MRSA was not isolated from production system B's swine or workers. Isolates examined were not typeable by PFGE when SmaI was used, but digestion with EagI revealed that the isolates were clonal and were not related to common human types in Iowa (USA100, USA300, and USA400). MLST documented that the isolates were ST398.ConclusionsThese results show that colonization of swine by MRSA was very common on one swine production system in the midwestern U.S., suggesting that agricultural animals could become an important reservoir for this bacterium. MRSA strain ST398 was the only strain documented on this farm. Further studies are examining carriage rates on additional farms.

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We demonstrated the complex beta-lactamase background of KPC-Kp isolates that are emerging in multiple centres in the Eastern USA. The prevalence of a single dominant clone suggests that interstate transmission has occurred.

Volume 46, no. 1, p. 150-156, 2008. In our recent report describing the in vitro susceptibility of 5,346 Candida spp. to the echinocandins, we noted the excellent activity of the echinocandins and the lack of evidence of emerging echinocandin resistance over 6 years of global surveillance. We also described 12 (out of a total of 2,869) isolates of Candida albicans that demonstrated a high-anidulafungin-MIC phenotype, which we defined as an anidulafungin MIC of 2 g/ml. We noted that these isolates, while still susceptible according to the recently approved Clinical and Laboratory Standards Institute (CLSI) breakpoint of Յ2 g/ml (minutes of the June 2007 meeting of the CLSI Antifungal Subcommittee), were nonetheless of interest because their echinocandin MICs were distinctly higher than the normal wild-type distribution of echinocandin MICs for C. albicans (page 152, column 2, lines 1-18).While pulling these 12 isolates from our bank for further evaluation, we noted that none of them demonstrated the characteristic green color of C. albicans on CHROMagar Candida ( Further evaluation of these isolates (with the assistance of David Pincus and Nancy Moss in the research and development group at bioMerieux, Inc.) revealed that all demonstrated the same atypical pattern for the Vitek YBC database (for C. parapsilosis), specifically for three reactions, those involving alpha methyl-D-glucoside (AMG), melezitose (MLZ), and xylitol (XLT). All 12 isolates were AMG negative, MLZ negative, and XLT positive in our hands. Based upon these three atypical reactions, the YBC algorithm generated C. albicans as the best match for each isolate. These findings were confirmed by sending the isolates to bioMerieux, Inc., for testing, which revealed highly variable AMG statuses (with only 3 of the 12 isolates being strongly negative), negative MLZ results for 11 of the 12 isolates, and positive XLT results for all 12 isolates. When tested with the API 20-C system, 11 of the 12 isolates were correctly identified as C. parapsilosis, and when tested on the Vitek 2 YST card, all 12 were correctly identified, with 3 of the 12 giving a "low discrimination" call with C. famata.We regret that we did not detect this species identification error prior to publication. At the time of the initial receipt and characterization of the isolates, all were identified as C. albicans based upon the Vitek YBC result. We are in the process of systematically assessing the error rate of our Vitek YBC system for identification of C. parapsilosis, in particular the rare misidentification of C. parapsilosis as C. albicans. Preliminary findings suggest that this is an uncommon event, occurring for fewer than 2% of all C. parapsilosis isolates tested on the YBC (data not shown). In each case of misidentification we have detected thus far, the CHROMagar appearance of the organism is not consistent with that of C. albicans. We no longer accept a Vitek YBC result of C. albicans for an isolate without a characteristic CHROMagar appearance. In addition, we confirm the id...

We tested a global collection of Candida sp. strains against anidulafungin, caspofungin, and micafungin, using CLSI M27-A3 broth microdilution (BMD) methods, in order to define wild-type (