Performance of diagnostic tests to detect respiratory viruses in older adults.

The performance of 4 laboratory methods for diagnosis of viral respiratory tract infections (RTI) in older adults was evaluated. Seventy-four nasopharyngeal (NP) swab specimens were obtained from 60 patients with RTI at a long-term care facility over 2 respiratory seasons. Sixteen specimens were positive for a respiratory virus by at least 1 method. Multiplex reverse transcriptase polymerase chain reaction (RT-PCR) by the Luminex xTAG Respiratory Viral Panel (RVP) detected 16 (100%) of the positive specimens, RVP of 24-h culture supernatant detected 8 (50%), direct fluorescent antibody testing detected 4 (25%), rapid culture detected 2 (12.5%), and rapid antigen testing detected none. For a comparison group, RVP was performed on NP swabs from 20 outpatient children with RTI. The mean fluorescence intensity by RVP was significantly lower for positive adult patients than pediatric patients (P = 0.0373). Our data suggest that older adult patients shed lower titers of viruses, necessitating a highly sensitive assay such as RT-PCR to reliably detect respiratory viral pathogens

Respiratory syncytial virus outbreak in a long-term care facility detected using reverse transcriptase polymerase chain reaction: an argument for real-time detection methods.

ObjectivesTo report an outbreak of respiratory synctyial virus (RSV) in a long-term care facility (LTCF) during ongoing routine respiratory illness surveillance.DesignRapid antigen testing, viral culture, direct fluorescent antibody (DFA) testing, and reverse transcriptase polymerase chain reaction (RT-PCR) testing for up to 15 viruses in symptomatic residents and chart review.SettingA 120-bed LTCF.MeasurementsComparison of rapid antigen testing, respiratory viral cultures, and DFA testing and RT-PCR in residents with symptoms of a respiratory tract infection.ResultsTwenty-two of 52 residents developed symptoms of a respiratory tract infection between January 29, 2008, and February 26, 2008. RSV was detected using RT-PCR in seven (32%) of the 22 cases. None of the seven cases had positive RSV rapid antigen testing, and only two had positive culture or DFA results. This outbreak occurred during a time when state wide RSV rates were rapidly declining. One patient was admitted to the hospital during the infection and subsequently died.ConclusionRSV may cause outbreaks in LTCFs that traditional diagnostic methods do not detect. RT-PCR can provide a more timely and accurate diagnosis of outbreaks, which allows for early symptomatic treatment, rational use of antibiotics, and improved infection control

State-of-the-Art Microbiologic Testing for Community-Acquired Meningitis and Encephalitis.

Meningitis and encephalitis are potentially life-threatening diseases with a wide array of infectious, postinfectious, and noninfectious causes. Diagnostic testing is central to determining the underlying etiology, treatment, and prognosis, but many patients remain undiagnosed due to suboptimal testing and lack of tests for all pathogens. In this article, we summarize the epidemiology, barriers to diagnosis, and current best tests for meningitis and encephalitis in developed countries. We end with a brief discussion of new test methods, such as multiplex panel-based tests and metagenomic sequencing, which are likely to alter diagnostic strategies for these conditions in the near future

Diagnostic Approach to Health Care- and Device-Associated Central Nervous System Infections

Health care- and device-associated central nervous system (CNS) infections have a distinct epidemiology, pathophysiology, and microbiology that require a unique diagnostic approach. Most clinical signs, symptoms, and tests used to diagnose community-acquired CNS infections are insensitive and nonspecific in neurosurgical patients due to postsurgical changes, invasive devices, prior antimicrobial exposure, and underlying CNS disease. The lack of a standardized definition of infection or diagnostic pathway has added to this challenge. In this review, we summarize the epidemiology, microbiology, and clinical presentation of these infections, discuss the issues with existing microbiologic tests, and give an overview of the current diagnostic approach

Evaluation of Escherichia coli Cell Response to Antibiotic Treatment by Use of Raman Spectroscopy with Laser Tweezers▿

Laser tweezers Raman spectroscopy was used to detect the cellular response of Escherichia coli cells to penicillin G-streptomycin and cefazolin. Time-dependent intensity changes of several Raman peaks at 729, 1,245, and 1,660 cm−1 enabled untreated cells and cells treated with the different antibiotic drugs to be distinguished