Angella Charnot-Katsikas

Two Cases of Necrotizing Fasciitis Due to Acinetobacter baumannii

ABSTRACT Necrotizing fasciitis has conventionally been associated with the streptococci, and when it is caused by other organisms, it is most often the result of a polymicrobial infection. We report on two cases of fatal monomicrobial necrotizing fasciitis due to Acinetobacter baumannii, an unusual finding that may be an indication of enhanced virulence of the organism.

Staphylococcus aureus infection induces protein A–mediated immune evasion in humans

Pauli et al. find that the active B cell response in patients infected with Staphylococcus aureus is predominately focused on a single antigen, SpA, which acts as a B cell superantigen. SpA-reactive antibodies dominate the response despite the presence of circulating B cells specific for other bacterial surface antigens.

Modified Carbapenem Inactivation Method for Phenotypic Detection of Carbapenemase Production among Enterobacteriaceae

ABSTRACT The ability of clinical microbiology laboratories to reliably detect carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CP-CRE) is an important element of the effort to prevent and contain the spread of these pathogens and an integral part of antimicrobial stewardship. All existing methods have limitations. A new, straightforward, inexpensive, and specific phenotypic method for the detection of carbapenemase production, the carbapenem inactivation method (CIM), was recently described. Here we describe a two-stage evaluation of a modified carbapenem inactivation method (mCIM), in which tryptic soy broth was substituted for water during the inactivation step and the length of this incubation was extended. A validation study was performed in a single clinical laboratory to determine the accuracy of the mCIM, followed by a nine-laboratory study to verify the reproducibility of these results and define the zone size cutoff that best discriminated between CP-CRE and members of the family Enterobacteriaceae that do not produce carbapenemases. Bacterial isolates previously characterized through whole-genome sequencing or targeted PCR as to the presence or absence of carbapenemase genes were tested for carbapenemase production using the mCIM; isolates with Ambler class A, B, and D carbapenemases, non-CP-CRE isolates, and carbapenem-susceptible isolates were included. The sensitivity of the mCIM observed in the validation study was 99% (95% confidence interval [95% CI], 93% to 100%), and the specificity was 100% (95% CI, 82% to 100%). In the second stage of the study, the range of sensitivities observed across nine laboratories was 93% to 100%, with a mean of 97%; the range of specificities was 97% to 100%, with a mean of 99%. The mCIM was easy to perform and interpret for Enterobacteriaceae, with results in less than 24 h and excellent reproducibility across laboratories.

Comparison of Cepheid Xpert® Flu/RSV XC and BioFire FilmArray® for detection of influenza A, influenza B, and respiratory syncytial virus

ABSTRACT The Xpert Flu/RSV XC was compared to the FilmArray respiratory panel for detection of influenza (Flu) A, Flu B, and respiratory syncytial virus (RSV), using 128 nasopharyngeal swabs. Positive agreements were 100% for Flu A and RSV and 92.3% for Flu B. The Xpert may be useful in clinical situations when extensive testing is not required and may serve an important role in laboratories already performing broader respiratory panel testing.

Prospective evaluation of the VITEK MS for the routine identification of bacteria and yeast in the clinical microbiology laboratory: assessment of accuracy of identification and turnaround time.

This study assessed the accuracy of bacterial and yeast identification using the VITEK MS, and the time to reporting of isolates before and after its implementation in routine clinical practice. Three hundred and sixty-two isolates of bacteria and yeast, consisting of a variety of clinical isolates and American Type Culture Collection strains, were tested. Results were compared with reference identifications from the VITEK 2 system and with 16S rRNA sequence analysis. The VITEK MS provided an acceptable identification to species level for 283 (78 %) isolates. Considering organisms for which genus-level identification is acceptable for routine clinical care, 315 isolates (87 %) had an acceptable identification. Six isolates (2 %) were identified incorrectly, five of which were Shigella species. Finally, the time for reporting the identifications was decreased significantly after implementation of the VITEK MS for a total mean reduction in time of 10.52 h (P<0.0001). Overall, accuracy of the VITEK MS was comparable or superior to that from the VITEK 2. The findings were also comparable to other studies examining the accuracy of the VITEK MS, although differences exist, depending on the diversity of species represented as well as on the versions of the databases used. The VITEK MS can be incorporated effectively into routine use in a clinical microbiology laboratory and future expansion of the database should provide improved accuracy for the identification of micro-organisms.

Use of the Accelerate Pheno System for Identification and Antimicrobial Susceptibility Testing of Pathogens in Positive Blood Cultures and Impact on Time to Results and Workflow

ABSTRACT The Accelerate Pheno system uses automated fluorescence in situ hybridization technology with morphokinetic cellular analysis to provide rapid species identification (ID) and antimicrobial susceptibility testing (AST) results for the most commonly identified organisms in bloodstream infections. The objective was to evaluate the accuracy and workflow of bacterial and yeast ID and bacterial AST using the Accelerate Pheno system in the clinical microbiology laboratory. The consecutive fresh blood cultures received in the laboratory were analyzed by the Accelerate Pheno system within 0 to 8 h of growth detection. ID/AST performance, the average times to results, and workflow were compared to those of the routine standard of care. Of the 232 blood cultures evaluated (223 monomicrobial and 9 polymicrobial) comprising 241 organisms, the overall sensitivity and specificity for the identification of organisms were 95.6% and 99.5%, respectively. For antimicrobial susceptibility, the overall essential agreement was 95.1% and categorical agreement was 95.5% compared to routine methods. There was one very major error and 3 major errors. The time to identification and the time to susceptibility using the Accelerate Pheno system were decreased by 23.47 and 41.86 h, respectively, compared to those for the standard of care. The reduction in hands on time was 25.5 min per culture. The Accelerate Pheno system provides rapid and accurate ID/AST results for most of the organisms found routinely in blood cultures. It is easy to use, reduces hands on time for ID/AST of common blood pathogens, and enables clinically actionable results to be released much earlier than with the current standard of care.

Comparison of turnaround time and time to oseltamivir discontinuation between two respiratory viral panel testing methodologies

Respiratory infections contribute to many Emergency Department visits and hospitalizations, resulting in a high healthcare burden (Neuzil et al., 2003; Schull et al., 2005). Rapid detection of respiratory pathogens in patients presenting with symptoms of an upper respiratory tract infection is crucial for timely determination of optimal antimicrobial management, avoidance of unnecessary evaluations and implementation of transmission-reducing infection control practices. Rapid viral testing can also result in cost savings to the healthcare system through reduction in Emergency Department boarding time and decreased duration of empiric antiviral therapy (Schull et al., 2005). With increased emphasis on antimicrobial stewardship in hospitals to facilitate improved clinical and economic outcomes with antimicrobial therapy, the implementation of rapid diagnostics for laboratory identification of pathogens is of great interest (Bauer et al., 2014). Multiplex PCR is a highly sensitive molecular method for accurate detection of respiratory pathogens and provides a more rapid turnaround time (TAT) compared with other respiratory viral testing methodologies. Our microbiology laboratory switched from the Luminex xTAG respiratory viral panel (RVP) (http://www.luminexcorp.com), which detects 12 respiratory viruses with an assay time of 8.5 h, performed two to three times per week to the Biofire Diagnostics FilmArray respiratory panel (RP) (http://filmarray.com), which detects 17 respiratory viral and three bacterial targets with an assay time of 1.2 h, performed 24 h a day/7 days per week. We compared the TAT between the two RVPs performed at different frequencies and determined the time to discontinuation of empiric oseltamivir among patients testing negative for influenza. All adult patients with an RVP test result reported between 1 December 2011 and 28 February 2012 performed on Luminex xTAG RVP (two to three times per week) and 1 December 2012 and 28 February 2013 performed on FilmArray RP (24 h a day/7 days per week) were evaluated for mean TAT. The mean TAT for the Luminex xTAG RVP (two to three times per week) between 1 December 2011 and 28 February 2012 (n = 230 assays) was 46.4 h compared with a mean TAT of 3.1 h (P<0.001) for FilmArray RP (24 h a day/7 days per week) between 1 December 2012 and 28 February 2013 (n = 872 assays) (Fig. 1). The mean time to discontinuation of empiric oseltamivir amongst patients with an RVP negative for influenza was 4 and 2 days for the Luminex xTAG RVP (n = 42) and FilmArray RP (n = 75) groups, respectively (P<0.001). The reduction in mean time to discontinuation of empiric oseltamivir resulted in cost savings of ~US

BioFire FilmArray Respiratory Panel for Detection of Enterovirus D68

34.16 per patient (using a wholesale acquisition cost for oseltamivir of US

Fulminant hepatic failure attributed to infection with human herpesvirus 6 (HHV-6) in an immunocompetent woman: A case report and review of the literature

8.54 per dose), which during the 2012–2013 peak influenza season would be an overall cost saving of US

The performance of Luminex ARIES ® Flu A/B & RSV and Cepheid Xpert ® Flu/RSV XC for the detection of influenza A, influenza B, and respiratory syncytial virus in prospective patient samples

2527.84. The amount of oseltamivir utilized after we began using the FilmArray RP (24 h a day/7 days per week) would cost US