An outbreak of severe respiratory tract infection due to human metapneumovirus in a long-term care facility for the elderly in Oregon.

Human metapneumovirus (hMPV) was demonstrated to be responsible for an outbreak of acute respiratory tract infection with high morbidity and mortality among residents of a long-term care facility for the elderly during the late spring-summer in Oregon. Respiratory virus infections are a common cause of death in the elderly and the burden of human metapneumovirus may be underestimated. This case report stresses the importance of hMPV in causing outbreaks in long-term care facilities for the elderly. Cough and elevated temperature were common to all the resident patient cases. Six resident patient cases had hMPV laboratory confirmation of which 5 had the diagnosis of pneumonia and 4 were hospitalized. The fatality rate was 33.3% among laboratory confirmed cases and 31.3.0% among probable resident patient cases. The signs and symptoms observed in the elderly with acute respiratory infection caused by hMPV are difficult to distinguish from those associated with other respiratory viruses and direct testing for hMPV with molecular methods should be routinely pursued to prevent nosocomial infections.

Blinded comparison of repetitive-sequence PCR and multilocus sequence typing for genotyping methicillin-resistant Staphylococcus aureus isolates from a children's hospital in St. Louis, Missouri.

We performed a blinded study to compare repetitive-sequence PCR and multilocus sequence typing for genotyping hospital- and community-acquired methicillin-resistant Staphylococcus aureus (MRSA). The MRSA strains that were sequence type 8 (ST8), staphylococcal cassette chromosome mec (SCCmec) type IV, and Panton-Valentine leukocidin-positive clustered separately from those that were ST5 and SCCmec type II.

Detection of methicillin-resistant Staphylococcus aureus directly from nasal swab specimens by a real-time PCR assay.

Screening for colonization with methicillin-resistant Staphylococcus aureus (MRSA) is a key aspect of infection control to limit the nosocomial spread of this organism. Current methods for the detection of MRSA in clinical microbiology laboratories, including molecularly based techniques, require a culture step and the isolation of pure colonies that result in a minimum of 20 to 24 h until a result is known. We describe a qualitative in vitro diagnostic test for the rapid detection of MRSA directly from nasal swab specimens (IDI-MRSA; Infectio Diagnostic, Inc., Sainte-Foy, Quebec, Canada), based upon a real-time PCR and direct detection of MRSA via amplicon hybridization with a fluorogenic target-specific molecular beacon probe. Samples from 288 patients were analyzed for the presence of MRSA with the IDI-MRSA assay, compared to detection by either direct plating or enrichment broth selective culture methods. The diagnostic values for this MRSA screening method were 91.7% sensitivity, 93.5% specificity, 82.5% positive predictive value, and 97.1% negative predictive value when compared to culture-based methods. The time from the start of processing of specimen to result was approximately 1.5 h. In our hands, the IDI-MRSA assay is a sensitive and specific test for detection of nasal colonization with MRSA and providing for same-day results, allowing more efficient and effective use of infection control resources to control MRSA in health care facilities.

Sublethal injury and resuscitation of Candida albicans after amphotericin B treatment.

Amphotericin B treatment was previously shown to inhibit Candida albicans reproduction and reduce the fluorescence of vitality-specific dyes without causing a corresponding increase in the fluorescence of the mortality-specific dyes bis-(1,3-dibutylbarbituric acid)trimethine oxonol and SYBR Green I. In the present study, we have confirmed these results and have shown that the numbers of CFU are reduced by 99.9% by treatment with 0.5 micro g of amphotericin B per ml for 10 h at 35 degrees C. This reduction was not due to fungal cell death. First, the level of reduction of the tetrazolium salt 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide increased in the presence of concentrations of amphotericin B that caused greater than 90% reductions in the numbers of CFU. Second, fungal cells treated with amphotericin B at a concentration of 0.5 micro g/ml were resuscitated by further incubation at 22 degrees C for 15 h in the continued presence of amphotericin B. Third, recovery of the ability to replicate was prevented by sequential treatment with 20 micro g of miconazole per ml, which also increased the fluorescence of mortality-specific dyes to near the maximal levels achieved with 0.9 micro g of amphotericin B per ml. Sequential treatment with fluconazole and flucytosine did not increase the levels of staining with the mortality-specific dyes. Itraconazole was less effective than ketoconazole, which was less effective than miconazole. The practice of equating the loss of the capacity of C. albicans to form colonies with fungal cell death may give incorrect results in assays with amphotericin B, and the results of assays with caution with other antifungal agents that are lipophilic or that possess significant postantifungal effects may need to be interpreted.

Comparative evaluation of a new fluorescent carboxyfluorescein diacetate-modified microdilution method for antifungal susceptibility testing of Candida albicans isolates.

This report presents a fluorescent carboxyfluorescein diacetate (CFDA)-modified microdilution method used for the susceptibility testing of Candida albicans to amphotericin B, fluconazole, ketoconazole, itraconazole, voriconazole, and flucytosine. Four different broth microdilution susceptibility testing methods were simultaneously evaluated at 24 and 48 h. The MICs determined using the CFDA-modified method (MIC(cfda)) were compared to those obtained by the standard broth microdilution method (MIC(visual)) and a procedure employing the indicator Alamar blue (MIC(alamar)). The reference MIC was determined visually as recommended by the NCCLS M27-A protocol, and then quantified spectrophotometrically following agitation (MIC(spec)). The CFDA-modified microdilution method was demonstrated to effectively determine the MICs for all the antifungal drugs tested at both 24 and 48 h. The results from both the MIC(spec) and MIC(cfda) methods yielded >80% agreement within +/-1 dilution and >90% agreement within +/-2 dilutions at 24 h in comparison to the reference MIC(visual) method, respectively. The trailing growth phenomenon that occurs with azole antifungal drugs and many strains of C. albicans did not inhibit the effectiveness of the MIC(spec) and MIC(cfda) methods. The MIC(spec) and MIC(cfda) methods shared 92.8% agreement within +/-1 dilution at 24 h and 87.6% agreement within +/-1 dilution at 48 h.