Barbara Haller

Increasing Prevalence of Methicillin-Resistant Staphylococcus aureus Infection in California Jails

Staphylococcus aureus clinical isolates obtained from patients who were inmates of the San Francisco County jail system showed an increase in the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) from 29%, in 1997, to 74%, in 2002; 91% of the MRSA isolates carried staphylococcal chromosomal cassette mec (SCCmec) type IV. Pulsed field gel electrophoresis and multilocus sequence typing demonstrated 2 major clonal groups. One of these clonal groups is genetically indistinguishable from the strain responsible for an outbreak of MRSA in the Los Angeles County jail system in 2002.

Evaluation of the Binax NOW, BD Directigen, and BD Directigen EZ Assays for Detection of Respiratory Syncytial Virus

ABSTRACT The Binax NOW assay (Binax, Inc., Portland, Maine) and the BD Directigen EZ assay (Becton Dickinson and Company, Sparks, Md.), two new rapid immunoassays for detection of respiratory syncytial virus (RSV), as well as the BD Directigen RSV assay (DRSV) (Becton Dickinson and Company) and direct immunofluorescence staining (DFA) were compared with culture for detection of RSV in fresh specimens from both children and adults during the 2002-2003 respiratory virus season. The majority (95%) of specimens were nasal or nasopharyngeal washes or aspirates. A total of 47 (26%) were culture positive for RSV. The overall sensitivities of DFA (n = 149), NOW (n = 118), EZ (n = 88), and DRSV (n = 180) compared with culture (n = 180) were 93, 89, 59, and 77%, respectively. The specificities of DFA, NOW, EZ, and DRSV were 97, 100, 98, and 96%, respectively. However, when results were separated into those from children and those from adults, DFA was the only rapid test adequate for detection of RSV (sensitivity of 100% compared to 0, 0, and 25% for NOW, EZ, and DRSV, respectively) in adults. For children the sensitivities of DFA, NOW, EZ, and DRSV were 93, 94, 72, and 81%. The NOW assay was the most sensitive and specific and the easiest to perform of the kit tests for detecting RSV in children. None of these three rapid kit tests was sensitive for detecting RSV in specimens from adults. DFA remains the rapid method of choice for detecting RSV in the adult population.

Intermediate vancomycin susceptibility in a community-associated MRSA clone.

We describe a case of treatment failure caused by a strain of USA300 community-associated methicillin-resistant Staphylococcus aureus (MRSA) with intermediate susceptibility to vancomycin and reduced susceptibility to daptomycin. The strain was isolated from the bone of a 56-year-old man with lumbar osteomyelitis after a 6-week treatment course of vancomycin for catheter-associated septic thrombophlebitis.

Streptococcus suis Meningitis, United States

Streptococcus suis Meningitis, United States

Simultaneous Runs of the Bayer VERSANT HIV-1 Version 3.0 and HCV bDNA Version 3.0 Quantitative Assays on the System 340 Platform Provide Reliable Quantitation and Improved Work Flow

ABSTRACT Branched DNA (bDNA) assays to quantify human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) consist of three distinct steps, including sample processing, hybridization, and detection, and utilize the System 340 platform for plate incubation and washing. Sample processing differs: HIV-1 from 1 ml of plasma is concentrated by high-speed centrifugation, whereas HCV plasma or serum samples are used without concentration. The first step of hybridization involves viral lysis at 63°C: HIV-1 is performed in a heat block, whereas HCV is performed in System 340. The remaining hybridization and detection steps are similar for HIV-1 and HCV and executed on System 340. In the present study, the HIV-1 bDNA assay was adapted for viral lysis in the System 340 platform. The adaptation, test method 2, includes a 20-s vortex of concentrated viral pellet and lysis working solution, transfer of viral lysate to the 96-well capture plate, and transfer to System 340 programmed for HCV assay specifications. With test method 2, specificity and quantification were within assay specifications. HCV bDNA methodology remains unchanged. Hence, an HIV-1 and an HCV bDNA can be run simultaneously on System 340. With simultaneous testing, laboratories can run full plates, as well as combinations of full and partial plates. Also, simultaneous HIV-1 and HCV bDNA permits labor consolidation and improved workflow while maintaining multitasking and rapid patient result turnaround.

Testing and Linkage to Care Outcomes for a Clinician-Initiated Rapid HIV Testing Program in an Urban Emergency Department

The urban emergency department is an important site for the detection of HIV infection. Current research has focused on strategies to increase HIV testing in the emergency department. As more emergency department HIV cases are identified, there need to be well-defined systems for linkage to care. We conducted a retrospective study of rapid HIV testing in an urban public emergency department and level I trauma center from June 1, 2008, to March 31, 2010. The objectives of this study were to evaluate the increase in the number of tests and new HIV diagnoses resulting from the addition of targeted testing to clinician-initiated diagnostic testing, describe the demographic and clinical characteristics of patients with newly diagnosed HIV infection, and assess the effectiveness of an HIV clinic based linkage to care team. Of 96,711 emergency department visits, there were 5340 (5.5%) rapid HIV tests performed, representing 4827 (91.3%) unique testers, of whom 62.4% were male and 60.8% were from racial/ethnic minority groups. After the change in testing strategy, the median number of tests per month increased from 114 to 273 (p=0.004), and the median number of new diagnoses per month increased from 1.5 to 4 (p=0.01). From all tests conducted, there were 65 new diagnoses of HIV infection (1.2%, 95% confidence interval [CI] 0.9%, 1.5%). The linkage team connected over 90% of newly diagnosed and out-of-care HIV-infected patients to care. In summary, the addition of targeted testing to diagnostic testing increased new HIV case identification, and an HIV clinic-based team was effective at linkage to care.

Impact of GeneXpert MTB/RIF Assay on Triage of Respiratory Isolation Rooms for Inpatients With Presumed Tuberculosis: A Hypothetical Trial

BACKGROUND Placing inpatients with presumed active pulmonary tuberculosis in respiratory isolation pending results of serial sputum acid-fast bacilli (AFB) smear microscopy is standard practice in high-income countries. However, this diagnostic strategy is slow and yields few tuberculosis diagnoses. We sought to determine if replacing microscopy with the GeneXpert MTB/RIF (Xpert) nucleic acid amplification assay could reduce testing time and usage of isolation rooms. METHODS We prospectively followed inpatients at San Francisco General Hospital undergoing tuberculosis evaluation. We performed smear microscopy and Xpert testing on concentrated sputum, and calculated diagnostic accuracy for both strategies in reference to serial sputum mycobacterial culture. We measured turnaround time for microscopy and estimated hypothetical turnaround times for Xpert on concentrated and unconcentrated sputum. We compared median and total isolation times for microscopy to those estimated for the 2 Xpert strategies. RESULTS Among 139 patients with 142 admissions, median age was 54 years (interquartile range [IQR], 43-60 years); 32 (23%) patients were female, and 42 (30%) were HIV seropositive. Serial sputum smear microscopy and a single concentrated sputum Xpert had identical sensitivity (89%; 95% confidence interval [CI], 52%-100%) and similar specificity (99% [95% CI, 96%-100%] vs 100% [95% CI, 97%-100%]). A single concentrated sputum Xpert could have saved a median of 35 hours (IQR, 24-36 hours) in unnecessary isolation compared with microscopy, and a single unconcentrated sputum Xpert, 45 hours (IQR, 35-46 hours). CONCLUSIONS Replacing serial sputum smear microscopy with a single sputum Xpert could eliminate most unnecessary isolation for inpatients with presumed tuberculosis, greatly benefiting patients and hospitals.

Leveraging a rapid, round-the-clock HIV testing system to screen for acute HIV infection in a large urban public medical center.

Objective:To describe the prevalence and location of new and acute HIV diagnoses in a large urban medical center. Secondary objectives were to evaluate rapid HIV test performance, the added yield of acute HIV screening, and linkage-to-care outcomes. Design:Cross-sectional study from November 1, 2008, to April 30, 2009. Methods:The hospital laboratory performed round-the-clock rapid HIV antibody testing on venipuncture specimens from patients undergoing HIV testing in hospital and community clinics, inpatient settings, and the emergency department (ED). For patients with negative results, a public health laboratory conducted pooled HIV RNA testing for acute HIV infection. The laboratories communicated positive results from the hospital campus to a linkage team. Linkage was defined as 1 outpatient HIV-related visit. Results:Among 7927 patients, 8550 rapid tests resulted in 137 cases of HIV infection [1.7%, 95% confidence interval (CI): 1.5% to 2.0%], of whom 46 were new HIV diagnoses (0.58%, 95% CI: 0.43% to 0.77%). Pooled HIV RNA testing of 6704 specimens (78.4%) resulted in 3 cases of acute HIV infection (0.05%, 95% CI: 0.01% to 0.14%) and increased HIV case detection by 3.5%. Half of new HIV diagnoses and two thirds of acute infections were detected in the ED and urgent care clinic. Rapid test sensitivity was 98.9% (95% CI: 93.8% to 99.8%) and the specificity 99.9% (95% CI: 99.7% to 99.9%). More than 95% of newly diagnosed and out-of-care HIV-infected patients were linked to care. Conclusions:Patients undergoing HIV testing in EDs and urgent care clinics may benefit from being simultaneously screened for acute HIV infection.

Prevalence and outcomes of cryptococcal antigenemia in HIV-seropositive patients hospitalized for suspected tuberculosis in Uganda.

Background:Cryptococcal infection occurs in HIV-seropositive patients and is associated with high mortality. However, limited information is available on the prevalence and outcomes of cryptococcal antigenemia among hospitalized HIV-seropositive patients in sub-Saharan Africa. Objectives:To determine the prevalence of and risk factors for cryptococcal antigenemia among HIV-seropositive patients presenting to Mulago Hospital (Kampala, Uganda) with unexplained cough ≥2 weeks and suspected tuberculosis (TB) and also to determine if antigenemia is associated with an increased mortality. Methods:Between September 2009 and September 2010, we enrolled consecutive HIV-seropositive adults hospitalized at Mulago Hospital with cough ≥2 weeks and suspected TB. Banked serum was tested for cryptococcal antigen. We compared demographic and clinical characteristics, and 2-month mortality in patients with and without cryptococcal antigenemia. Results:Of 563 HIV-seropositive patients, 32 (5.7%) were cryptococcal antigen (CrAg) positive. None had Cryptococcus neoformans detected on fungal culture of bronchoalveolar lavage fluid (n = 116). CrAg-positive patients had a lower median CD4 count compared with CrAg-negative patients (25 vs. 55 cells/&mgr;L, P = 0.02), and a substantial proportion of CrAg-positive patients also had concurrent TB (31%). A positive CrAg test was not associated with increased mortality during the 2-month follow-up period (hazard ratio: 0.99, 95% confidence interval: 0.63 to 1.54, P = 0.95) after adjusting for CD4 count and antiretroviral therapy use at enrollment and/or follow-up. Conclusions:Occult cryptococcal antigenemia occurs commonly among hospitalized HIV-seropositive patients with suspected TB. CrAg testing should be considered in hospitalized HIV-seropositive patients with CD4 count <50 cells/&mgr;L, coupled with longer follow-up to evaluate the diagnostic value of CrAg and therapeutic interventions in patients with asymptomatic cryptococcal antigenemia.

Multiple-use atomizers in outpatient otolaryngology clinics are not necessarily an infectious risk.

OBJECTIVE We sought to determine the risk of bacterial transmission from multiple-use atomizers in an outpatient otolaryngology clinic. STUDY DESIGN AND SETTING Atomizers in 6 examination rooms were analyzed for bacterial contamination. Sterility of associated tubing from 1 atomizer was assessed. Multidose drug solutions in the atomizers (phenylephrine and tetracaine) were cultured multiple times over a 2-week period. Serial dilutions of the original sample were cultured to minimize inhibitory effects of antiseptic agents in the drug formulations. RESULTS No bacteria were recovered from tubing cultures. Only 2 (0.6%) of 336 cultures of the drug solutions yielded bacterial growth. In both cases, coagulase-negative Staphylococcus was recovered in 1 of the dilutions prepared from original samplings. CONCLUSION Multiple-use atomizers that contain phenylephrine and tetracaine solutions with bacteriostatic preservatives in an outpatient otolaryngology clinic do not yield significant bacterial growth and, when used as described, do not pose an infectious risk of bacterial transmission between patients.