BackgroundThe incidence of nosocomial infections from extensively drug-resistant Pseudomonas aeruginosa (XDR-PA) has been increasing worldwide. We investigated the prevalence and factors associated with XDR-PA infections, including the factors that predict mortality.MethodsWe retrospectively studied a cohort of adult, hospitalized patients with P. aeruginosa (PA) infections between April and December 2014.ResultsOf the 255 patients with PA infections, 56 (22%) were due to XDR-PA, 32 (12.5%) to multidrug resistant Pseudomonas aeruginosa (MDR-PA), and 167 (65.5%) to non-MDR PA. Receiving total parenteral nutrition (adjusted OR [aOR] 6.21; 95% CI 1.05–36.70), prior carbapenem use (aOR 4.88; 95% CI 2.36–10.08), and prior fluoroquinolone use (aOR 3.38; 95% CI 1.44–7.97) were independently associated with the XDR-PA infections. All XDR-PA remained susceptible to colistin. Factors associated with mortality attributable to the infections were the presence of sepsis/septic shock (aOR 11.60; 95% CI 4.66–28.82), admission to a medical department (aOR 4.67; 95% CI 1.81–12.06), receiving a central venous catheter (aOR 3.78; 95% CI 1.50–9.57), and XDR-PA infection (aOR 2.73; 95% CI 1.05–7.08).ConclusionThe prevalence of XDR-PA infections represented almost a quarter of Pseudomonas aeruginosa hospital-acquired infections and rendered a higher mortality. The prompt administration of an appropriate empirical antibiotic should be considered when an XDR-PA infection is suspected.

The cryptococcal antigen lateral flow assay (CrAg LFA) was evaluated for the diagnosis of cryptococcosis in HIV-negative patients. The sensitivity was excellent, suggesting that this assay can replace conventional testing based on latex agglutination (LA). CrAg LFA and LA titers were correlated but were not directly comparable, with implications for conversion between assays. C ryptococcosis is a systemic infection caused by Cryptococcus neoformans and Cryptococcus gattii. The cryptococcal antigen lateral flow assay (CrAg LFA; IMMY Inc., Norman, OK) is a recently developed dipstick sandwich immunochromatographic assay that has shown equivalent or superior overall sensitivity compared to that of enzyme immunoassay (EIA) and latex agglutination (LA) tests (1-5) and has demonstrated good individual sensitivity for the capsular polysaccharide glucuronoxylomannan (GXM) of all four C. neoformans serotypes (6). However, most comparative studies have relied primarily on samples from HIV patients (1, 2, 7-9), so little is known about the relative performance of CrAg LFA in HIV-negative individuals, in whom fungal burden may be lower. The present study aimed to evaluate the sensitivity of CrAg LFA in diagnosing cryptococcosis in HIV-negative adults.(This work was presented in part at the 115th General Meeting of the American Society for Microbiology, New Orleans, LA, 30 May to 2 June 2015.)We first conducted a validation of the CrAg LFA assay using 36 frozen archival serum samples (26 positive/10 negative) and 23 cerebrospinal fluid (CSF) specimens (13 positive/10 negative) that were previously tested in the laboratory by LA (CALAS; Meridian Bioscience Inc., Cincinnati, OH). This was performed on archived specimens gathered from patients on an Institutional Review Board (IRB)-approved clinical protocol. Retesting of these specimens by qualitative and semiquantitative CrAg LFA demonstrated 100% agreement with previously tested LA-positive and LA-negative samples in this set. The relative limits of detection of LA and LFA were then tested in two experiments in which serum and CSF specimens were serially diluted to final negative titers for the two assays tested in parallel. The LFA assay remained positive at substantially greater dilutions than the LA assay did for the tested specimens: Final titers (LFA versus LA) were 1:8,192 versus 1:512 for serum and 1:8,192 versus 1:128 for CSF, which is consistent with a lower limit of detection for the LFA assay for the two specimen types.Following validation, the qualitative and semiquantitative CrAg LFA assays were performed on archived specimens collected from HIV-negative individuals with confirmed diagnoses of cryptococcosis. To challenge the limits of sensitivity of the LFA assay, specimens were selected that had tested negative by EIA, potentially reflecting lower antigen titers. All but four of these samples tested positive by LA. Statistical analysis of LFA results was performed with Prism version 6.0 (GraphPad Software, Inc.), and all values are expressed herein as mean plu...