Evaluation of a Novel Light Scattering Methodology for the Detection of Pathogenic Bacteria in Urine.

BACKGROUND: Urine culture, the gold standard for detecting and identifying bacteria in urine, is one of the highest volume tests in many microbiology laboratories. The inability to accurately predict which patients would benefit from culture leads not only to monopolization of laboratory resources, but also to unnecessary antimicrobial exposure as patients receive empirical treatment for suspected or presumed urinary tract infections (UTI) while awaiting culture results. A common approach to decrease unnecessary urine culture is screening samples using urinalysis (UA) parameters to determine those that should proceed to culture (reflex). In this study, we compared the performance of a novel uropathogen detection method to urinalysis for purposes of UTI screening. METHODS: Urine specimens submitted for culture (n = 194) were evaluated by urinalysis and a novel light scattering device (BacterioScan 216Dx UTI System) capable of detecting the presence of bacteria in urine. Sensitivity and specificity for prediction of a positive urine culture by UA and 216Dx were determined relative to urine culture results. A positive urine culture was defined as growth in culture of one or two uropathogens at concentrations of ≥50,000 CFU/mL. RESULTS: 194 urine samples were evaluated by UA, 216Dx, and urine culture. The 216Dx demonstrated a 100% [95%CI: 88.43%-100.0%] sensitivity and 81.71% [95%CI: 74.93%-87.30%] specificity for the detection of bacteriuria, vs UA with a sensitivity of 86.67% [95%CI 69.28%-96.24%] and specificity of 71.95% [95%CI: 64.41%-78.68%] when compared to urine culture (diagnostic reference method). CONCLUSIONS: BacterioScan allows for an alternative method of screening with satisfactory sensitivity and improved specificity that may facilitate a reduction of unnecessary cultures. Additional studies are required to determine if a concomitant decrease in inappropriate antibiotic use can be realized with the 216Dx technology.

Multicenter Evaluation of the ePlex Respiratory Pathogen Panel for the Detection of Viral and Bacterial Respiratory Tract Pathogens in Nasopharyngeal Swabs.

The performance of the new ePlex Respiratory Pathogen (RP) panel (GenMark Diagnostics) for the simultaneous detection of 19 viruses (influenza A virus; influenza A H1 virus; influenza A 2009 H1 virus; influenza A H3 virus; influenza B virus; adenovirus; coronaviruses [HKU1, OC43, NL63, and 229E]; human rhinovirus/enterovirus; human metapneumovirus; parainfluenza viruses 1, 2, 3, and 4; and respiratory syncytial virus [RSV] [RSV subtype A and RSV subtype B]) and 2 bacteria (Mycoplasma pneumoniae and Chlamydia pneumoniae) was evaluated. Prospectively and retrospectively collected nasopharyngeal swab (NPS) specimens (n = 2,908) were evaluated by using the ePlex RP panel, with the bioMérieux/BioFire FilmArray Respiratory Panel (BioFire RP) as the comparator method. Discordance analysis was performed by using target-specific PCRs and bidirectional sequencing. The reproducibility of the assay was evaluated by using reproducibility panels comprised of 6 pathogens. The overall agreement between the ePlex RP and BioFire RP results was >95% for all targets. Positive percent agreement with the BioFire RP result for viruses ranged from 85.1% (95% confidence interval [CI], 80.2% to 88.9%) to 95.1% (95% CI, 89.0% to 97.9%), while negative percent agreement values ranged from 99.5% (95% CI, 99.1% to 99.7%) to 99.8% (95% CI, 99.5% to 99.9%). Additional testing of discordant targets (12%; 349/2,908) confirmed the results of ePlex RP for 38% (131/349) of samples tested. Reproducibility was 100% for all targets tested, with the exception of adenovirus, for which reproducibilities were 91.6% at low virus concentrations and 100% at moderate virus concentrations. The ePlex RP panel offers a new, rapid, and sensitive "sample-to-answer" multiplex panel for the detection of the most common viral and bacterial respiratory pathogens.

Cutting to the Core of the Issue: Emerging Strategies To Reduce Prostate Biopsy-Related Infections.

Over 1 million men undergo biopsy in the United States each year to evaluate for prostate cancer (S. Loeb, H. B. Carter, S. I. Berndt, W. Ricker, and E. M. Schaeffer, J Urol 186:1830-1834, 2011, http://dx.doi.org/10.1016/j.juro.2011.06.057). In recent years, there has been a rise in infectious complications related to these procedures. This review aims to provide an overview of the guidelines that direct transrectal prostate biopsy, to describe associated infection, and to evaluate the published data driving the current trend toward prebiopsy screening for resistant organisms.

Prevalence and Seasonal Distribution of Norovirus Detection in Stools Submitted From Pediatric Patients for Enteric Pathogen Testing.

The prevalence and seasonal distribution of norovirus infection in children is not well defined. In this study, stool specimens from children suspected of having gastroenteritis were evaluated for the presence of norovirus. When tested retrospectively, 17.4% of samples were positive, primarily with Genogroup GII, peaking in fall and winter.

Investigation of cell phones as a potential source of bacterial contamination in the operating room.

BACKGROUND: Cell phone use has become common in areas of the hospital, including the operating room. The purpose of this study was to document the frequency of bacterial contamination on the cell phones of orthopaedic surgeons in the operating room and to determine whether a standardized disinfecting protocol decreased the rate of bacterial contamination and the amount of organic material. METHODS: Orthopaedic attending and resident cell phones were swabbed on the front and back in the operating room with adenosine triphosphate bioluminescence to quantify organic material contamination and culture swabs to evaluate bacterial contamination. Adenosine triphosphate was quantified with use of relative light units. One photon of light was emitted for each molecule of adenosine triphosphate. Thresholds of 250 and 500 relative light units were used. The phones were cleaned with a cleaning wipe and were retested. One week later, a final set of studies was obtained. Fifty-three participants were enrolled in this study. Pathogenic bacteria were defined as those commonly causing surgical site infections. RESULTS: Of fifty-three cell phones, 83% (forty-four cell phones) had pathogenic bacteria at initial testing, 8% (four cell phones) had pathogenic bacteria after disinfection, and 75% (forty cell phones) had pathogenic bacteria one week later. The mean result (and standard deviation) at initial testing was 3488 ± 2998 relative light units, which reduced after disinfection to 200 ± 123 relative light units, indicating a cleaned surface, but increased one week later to 1825 ± 1699 relative light units, indicating a poorly cleaned surface. CONCLUSIONS: The cell phones of orthopaedic surgeons had a high rate of pathogenic bacteria and organic material contamination. Both were decreased after a single disinfecting process. However, recontamination occurred. It seems prudent to routinely disinfect them or avoid their use in the operating room. CLINICAL RELEVANCE: The current study investigates orthopaedic surgeons' cell phones as a potential source of nosocomial infection in the operating room. On the basis of the high percentage of cell phone contamination found, we would recommend periodic cell phone cleaning with either the wipes used in our study or similar ones. In addition, given that there was a high contamination rate one week after disinfection, we would recommend considering cell phone cleaning more frequently than once a week.

Renal abscess caused by a Providencia stuartii isolate biochemically misidentified as Pasteurella.

Providencia stuartii is associated with urinary tract infection (UTI) in catheterized patients. Here we report an abscess containing P. stuartii in a patient with a history of UTI, renal stones, and stent placement. This organism was identified by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry and 16S rRNA gene sequencing following biochemical identification as Pasteurella.

Development and evaluation of a novel, semiautomated Clostridium difficile typing platform.

We describe a novel, semiautomated Clostridium difficile typing platform that is based on PCR-ribotyping in conjunction with a semiautomated molecular typing system. The platform is reproducible with minimal intra- or interassay variability. This method exhibited a discriminatory index of 0.954 and is therefore comparable to more arduous typing systems, such as pulsed-field gel electrophoresis.

Staphylococcus aureus α-hemolysin mediates virulence in a murine model of severe pneumonia through activation of the NLRP3 inflammasome.

Staphylococcus aureus is a dangerous pathogen that can cause necrotizing infections characterized by massive inflammatory responses and tissue destruction. Staphylococcal α-hemolysin is an essential virulence factor in severe S. aureus pneumonia. It activates the nucleotide-binding domain and leucine-rich repeat containing gene family, pyrin domain containing 3 (NLRP3) inflammasome to induce production of interleukin-1ß and programmed necrotic cell death. We sought to determine the role of α-hemolysin-mediated activation of NLRP3 in the pathogenesis of S. aureus pneumonia. We show that α-hemolysin activates the NLRP3 inflammasome during S. aureus pneumonia, inducing necrotic pulmonary injury. Moreover, Nlrp3(-/-) mice have less-severe pneumonia. Pulmonary injury induced by isolated α-hemolysin or live S. aureus is independent of interleukin-1ß signaling, implicating NLRP3-induced necrosis in the pathogenesis of severe infection. This work demonstrates the exploitation of host inflammatory signaling by S. aureus and suggests the NLRP3 inflammasome as a potential target for pharmacologic interventions in severe S. aureus infections.