Multicenter Evaluation of BioFire FilmArray Respiratory Panel 2 for Detection of Viruses and Bacteria in Nasopharyngeal Swab Samples.

The FilmArray Respiratory Panel 2 (RP2) is a multiplex in vitro diagnostic test for the simultaneous and rapid (∼45-min) detection of 22 pathogens directly from nasopharyngeal swab (NPS) samples. It contains updated (and in some instances redesigned) assays that improve upon the FilmArray Respiratory Panel (RP; version 1.7), with a faster run time. The organisms identified are adenovirus, coronavirus 229E, coronavirus HKU1, coronavirus NL63, coronavirus OC43, human metapneumovirus, human rhinovirus/enterovirus, influenza virus A, influenza virus A H1, influenza virus A H1-2009, influenza virus A H3, influenza virus B, parainfluenza virus 1, parainfluenza virus 2, parainfluenza virus 3, parainfluenza virus 4, respiratory syncytial virus, Bordetella pertussis, Chlamydia pneumoniae, and Mycoplasma pneumoniae Two new targets are included in the FilmArray RP2: Middle East respiratory syndrome coronavirus and Bordetella parapertussis This study provides data from a multicenter evaluation of 1,612 prospectively collected NPS samples, with performance compared to that of the FilmArray RP or PCR and sequencing. The overall percent agreement between the FilmArray RP2 and the comparator testing was 99.2%. The RP2 demonstrated a positive percent agreement of 91.7% or greater for detection of all but three analytes: coronavirus OC43, B. parapertussis, and B. pertussis The FilmArray RP2 also demonstrated a negative percent agreement of ≥93.8% for all analytes. Of note, the adenovirus assay detects all genotypes, with a demonstrated increase in sensitivity. The FilmArray RP2 represents a significant improvement over the FilmArray RP, with a substantially shorter run time that could aid in the diagnosis of respiratory infections in a variety of clinical scenarios.

Multicenter Evaluation of the Accelerate PhenoTest BC Kit for Rapid Identification and Phenotypic Antimicrobial Susceptibility Testing Using Morphokinetic Cellular Analysis.

We describe results from a multicenter study evaluating the Accelerate Pheno system, a first of its kind diagnostic system that rapidly identifies common bloodstream pathogens from positive blood cultures within 90 min and determines bacterial phenotypic antimicrobial susceptibility testing (AST) results within ∼7 h. A combination of fresh clinical and seeded blood cultures were tested, and results from the Accelerate Pheno system were compared to Vitek 2 results for identification (ID) and broth microdilution or disk diffusion for AST. The Accelerate Pheno system accurately identified 14 common bacterial pathogens and two Candida spp. with sensitivities ranging from 94.6 to 100%. Of fresh positive blood cultures, 89% received a monomicrobial call with a positive predictive value of 97.3%. Six common Gram-positive cocci were evaluated for ID. Five were tested against eight antibiotics, two resistance phenotypes (methicillin-resistant Staphylococcus aureus and Staphylococcus spp. [MRSA/MRS]), and inducible clindamycin resistance (MLSb). From the 4,142 AST results, the overall essential agreement (EA) and categorical agreement (CA) were 97.6% and 97.9%, respectively. Overall very major error (VME), major error (ME), and minor error (mE) rates were 1.0%, 0.7%, and 1.3%, respectively. Eight species of Gram-negative rods were evaluated against 15 antibiotics. From the 6,331 AST results, overall EA and CA were 95.4% and 94.3%, respectively. Overall VME, ME, and mE rates were 0.5%, 0.9%, and 4.8%, respectively. The Accelerate Pheno system has the unique ability to identify and provide phenotypic MIC and categorical AST results in a few hours directly from positive blood culture bottles and support accurate antimicrobial adjustment.

The Clinical Urine Culture: Enhanced Techniques Improve Detection of Clinically Relevant Microorganisms.

Enhanced quantitative urine culture (EQUC) detects live microorganisms in the vast majority of urine specimens reported as "no growth" by the standard urine culture protocol. Here, we evaluated an expanded set of EQUC conditions (expanded-spectrum EQUC) to identify an optimal version that provides a more complete description of uropathogens in women experiencing urinary tract infection (UTI)-like symptoms. One hundred fifty adult urogynecology patient-participants were characterized using a self-completed validated UTI symptom assessment (UTISA) questionnaire and asked "Do you feel you have a UTI?" Women responding negatively were recruited into the no-UTI cohort, while women responding affirmatively were recruited into the UTI cohort; the latter cohort was reassessed with the UTISA questionnaire 3 to 7 days later. Baseline catheterized urine samples were plated using both standard urine culture and expanded-spectrum EQUC protocols: standard urine culture inoculated at 1 µl onto 2 agars incubated aerobically; expanded-spectrum EQUC inoculated at three different volumes of urine onto 7 combinations of agars and environments. Compared to expanded-spectrum EQUC, standard urine culture missed 67% of uropathogens overall and 50% in participants with severe urinary symptoms. Thirty-six percent of participants with missed uropathogens reported no symptom resolution after treatment by standard urine culture results. Optimal detection of uropathogens could be achieved using the following: 100 µl of urine plated onto blood (blood agar plate [BAP]), colistin-nalidixic acid (CNA), and MacConkey agars in 5% CO2 for 48 h. This streamlined EQUC protocol achieved 84% uropathogen detection relative to 33% detection by standard urine culture. The streamlined EQUC protocol improves detection of uropathogens that are likely relevant for symptomatic women, giving clinicians the opportunity to receive additional information not currently reported using standard urine culture techniques.

Evaluation of the FilmArray Blood Culture Identification Panel: Results of a Multicenter Controlled Trial.

Sepsis is a major cause of morbidity, mortality, and increased medical expense. Rapid diagnosis improves outcomes and reduces costs. The FilmArray blood culture identification panel (BioFire Diagnostics LLC, Salt Lake City, UT), a highly multiplexed PCR assay, can identify 24 etiologic agents of sepsis (8 Gram-positive, 11 Gram-negative, and 5 yeast species) and three antimicrobial resistance genes (mecA, vanA/B, and blaKPC) from positive blood culture bottles. It provides results in about 1 h with 2 min for assay setup. We present the results of an eight-center trial comparing the sensitivity and specificity of the panel with those of the laboratories' standard phenotypic identification techniques, as well as with molecular methods used to distinguish Acinetobacter baumannii from other members of the A. calcoaceticus-A. baumannii complex and to detect antimicrobial resistance genes. Testing included 2,207 positive aerobic blood culture samples, 1,568 clinical and 639 seeded. Samples were tested fresh or were frozen for later testing within 8 h after the bottles were flagged as positive by an automated blood culture system. At least one organism was detected by the panel in 1,382 (88.1%) of the positive clinical specimens. The others contained primarily off-panel organisms. The panel reported multiple organisms in 81 (5.86%) positive clinical specimens. The unresolved blood culture identification sensitivity for all target detections exceeded 96%, except for Klebsiella oxytoca (92.2%), which achieved 98.3% sensitivity after resolution of an unavoidable phenotypic error. The sensitivity and specificity for vanA/B and blaKPC were 100%; those for mecA were 98.4 and 98.3%, respectively.

Multicenter Evaluation of BioFire FilmArray Meningitis/Encephalitis Panel for Detection of Bacteria, Viruses, and Yeast in Cerebrospinal Fluid Specimens.

Rapid diagnosis and treatment of infectious meningitis and encephalitis are critical to minimize morbidity and mortality. Comprehensive testing of cerebrospinal fluid (CSF) often includes Gram stain, culture, antigen detection, and molecular methods, paired with chemical and cellular analyses. These methods may lack sensitivity or specificity, can take several days, and require significant volume for complete analysis. The FilmArray Meningitis/Encephalitis (ME) Panel is a multiplexed in vitro diagnostic test for the simultaneous, rapid (∼1-h) detection of 14 pathogens directly from CSF specimens: Escherichia coli K1, Haemophilus influenzae, Listeria monocytogenes, Neisseria meningitidis, Streptococcus pneumoniae, Streptococcus agalactiae, cytomegalovirus, enterovirus, herpes simplex virus 1 and 2, human herpesvirus 6, human parechovirus, varicella-zoster virus, and Cryptococcus neoformans/Cryptococcus gattii We describe a multicenter evaluation of 1,560 prospectively collected CSF specimens with performance compared to culture (bacterial analytes) and PCR (all other analytes). The FilmArray ME Panel demonstrated a sensitivity or positive percentage of agreement of 100% for 9 of 14 analytes. Enterovirus and human herpesvirus type 6 had agreements of 95.7% and 85.7%, and L. monocytogenes and N. meningitidis were not observed in the study. For S. agalactiae, there was a single false-positive and false-negative result each, for a sensitivity and specificity of 0 and 99.9%, respectively. The specificity or negative percentage of agreement was 99.2% or greater for all other analytes. The FilmArray ME Panel is a sensitive and specific test to aid in diagnosis of ME. With use of this comprehensive and rapid test, improved patient outcomes and antimicrobial stewardship are anticipated.

Incontinence medication response relates to the female urinary microbiota.

INTRODUCTION AND HYPOTHESIS: Many adult women have resident urinary bacteria (urinary microbiome/microbiota). In adult women affected by urinary urgency incontinence (UUI), the etiologic and/or therapeutic role of the urinary microbiome/microbiota remains unknown. We hypothesized that microbiome/microbiota characteristics would relate to clinically relevant treatment response to UUI medication per os. METHODS: Adult women initiating medication treatment orally for UUI and a comparator group of unaffected women were recruited in a tertiary care health-care system. All participants provided baseline clinical data and urine samples. Women with UUI were given 5 mg solifenacin, with potential dose escalation to 10 mg for inadequate UUI symptom control at 4 weeks. Additional data and urine samples were collected from women with UUI at 4 and 12 weeks. The samples were assessed using 16S ribosomal RNA (rRNA) gene sequencing and enhanced quantitative urine culturing. The primary outcome was treatment response as measured by the validated Patient Global Symptom Control (PGSC) questionnaire. Clinically relevant UUI symptom control was defined as a 4 or 5 score on the PGSC. RESULTS: Diversity and composition of the urinary microbiome/microbiota of women with and without UUI differed at baseline. Women with UUI had more bacteria and a more diverse microbiome/microbiota. The clinical response to solifenacin in UUI participants was related to baseline microbiome/microbiota, with responders more likely to have fewer bacteria and a less diverse community at baseline. Nonresponders had a more diverse community that often included bacteria not typically found in responders. CONCLUSIONS: Knowledge of an individual's urinary microbiome/microbiota may help refine UUI treatment. Complementary tools, DNA sequencing, and expanded urine culture provide information about bacteria that appear to be related to UUI incontinence status and treatment response in this population of adult women.

Point-Counterpoint: Large Multiplex PCR Panels Should Be First-Line Tests for Detection of Respiratory and Intestinal Pathogens.

The first FDA-approved multiplex PCR panel for a large number of respiratory pathogens was introduced in 2008. Since then, other PCR panels for detection of several respiratory and gastrointestinal pathogens have been approved by the FDA and are commercially available, and more such panels are likely to become available. These assays detect 12 to 20 pathogens, and some include pathogens that typically cause different manifestations of infection, although they infect the same organ system. Some of these tests are labor-intensive, while others require little labor, and all of them are expensive, both for the laboratory and for the patient or insurer. They include a bundle of tests with limited or no options for selecting which tests will be performed. Laboratories and hospitals have adopted different strategies for offering these assays. Some have implemented strategies to limit the use of the tests, such as limiting the frequency with which patients can be tested, restricting testing to specific groups of patients (e.g., immunocompromised patients), or providing education to encourage the use of less expensive tests before using large multiplex panels. Others have offered these assays without limiting their use, either relying on the ordering provider to exercise good judgment or because such assays are thought to be appropriate for first-line diagnostic testing. In this Point-Counterpoint, Paul Schreckenberger of Loyola University Medical Center explains why his laboratory offers these assays without restriction. Alex McAdam of Boston's Children Hospital explains the concerns about the use of these assays as first-line tests and why some limitations on their use might be appropriate.

Definitive Identification of Laribacter hongkongensis Acquired in the United States.

Laribacter hongkongensis is a potential emerging pathogen associated with community-acquired gastroenteritis and traveler's diarrhea. We report the isolation of L. hongkongensis from the stool of a patient who had no history of travel outside the United States. The organism was identified by phenotypic tests, mass spectrometry, and gene sequencing.

Urine is not sterile: use of enhanced urine culture techniques to detect resident bacterial flora in the adult female bladder.

Our previous study showed that bacterial genomes can be identified using 16S rRNA sequencing in urine specimens of both symptomatic and asymptomatic patients who are culture negative according to standard urine culture protocols. In the present study, we used a modified culture protocol that included plating larger volumes of urine, incubation under varied atmospheric conditions, and prolonged incubation times to demonstrate that many of the organisms identified in urine by 16S rRNA gene sequencing are, in fact, cultivable using an expanded quantitative urine culture (EQUC) protocol. Sixty-five urine specimens (from 41 patients with overactive bladder and 24 controls) were examined using both the standard and EQUC culture techniques. Fifty-two of the 65 urine samples (80%) grew bacterial species using EQUC, while the majority of these (48/52 [92%]) were reported as no growth at 10(3) CFU/ml by the clinical microbiology laboratory using the standard urine culture protocol. Thirty-five different genera and 85 different species were identified by EQUC. The most prevalent genera isolated were Lactobacillus (15%), followed by Corynebacterium (14.2%), Streptococcus (11.9%), Actinomyces (6.9%), and Staphylococcus (6.9%). Other genera commonly isolated include Aerococcus, Gardnerella, Bifidobacterium, and Actinobaculum. Our current study demonstrates that urine contains communities of living bacteria that comprise a resident female urine microbiota.

Day of surgery urine cultures identify urogynecologic patients at increased risk for postoperative urinary tract infection.

PURPOSE: Despite preoperative screening and treatment for urinary tract infections, a postoperative urinary tract infection develops in approximately 1 in 5 urogynecologic patients. In this study we assess the proportion of urogynecologic patients with a positive day of surgery urine culture, the clinical consequences of a positive day of surgery culture and differences in postoperative urinary tract infection risks based on day of surgery culture. MATERIALS AND METHODS: After institutional review board approval, patients undergoing urogynecologic surgery at Loyola University Medical Center were recruited for the study. Catheterized urine samples were collected in the operating room before intravenous antibiotic administration. Clinical cultures were considered positive if 1,000 colonies per ml or more bacteria were found on routine culture. For analysis we matched each woman with a positive culture with 2 women with negative culture by age within 10 years and within surgical groups (ie prolapse and/or incontinence). Data were analyzed using SPSS® version 19. RESULTS: Nearly a tenth (9.5%) of participants had positive day of surgery cultures. The clinical and demographic characteristics were similar in women with negative vs positive day of surgery cultures. However, women with positive day of surgery cultures were more likely to experience a postoperative urinary tract infection despite standard perioperative antibiotic administration (29.6% vs 5.6%, p = 0.005, odds ratio 7.2). Regardless of day of surgery culture status no participant experienced postoperative systemic urinary complications. CONCLUSIONS: Nearly a tenth of urogynecologic patients had positive day of surgery cultures. Patients with a positive day of surgery culture had an increased risk (29.6%) of postoperative urinary tract infection within 6 weeks of surgery. These findings highlight an opportunity to identify and treat patients with positive day of surgery cultures and reduce the incidence of postoperative urinary tract infections.

Evidence of uncultivated bacteria in the adult female bladder.

Clinical urine specimens are usually considered to be sterile when they do not yield uropathogens using standard clinical cultivation procedures. Our aim was to test if the adult female bladder might contain bacteria that are not identified by these routine procedures. An additional aim was to identify and recommend the appropriate urine collection method for the study of bacterial communities in the female bladder. Consenting participants who were free of known urinary tract infection provided urine samples by voided, transurethral, and/or suprapubic collection methods. The presence of bacteria in these samples was assessed by bacterial culture, light microscopy, and 16S rRNA gene sequencing. Bacteria that are not or cannot be routinely cultivated (hereinafter called uncultivated bacteria) were common in voided urine, urine collected by transurethral catheter (TUC), and urine collected by suprapubic aspirate (SPA), regardless of whether the subjects had urinary symptoms. Voided urine samples contained mixtures of urinary and genital tract bacteria. Communities identified in parallel urine samples collected by TUC and SPA were similar. Uncultivated bacteria are clearly present in the bladders of some women. It remains unclear if these bacteria are viable and/or if their presence is relevant to idiopathic urinary tract conditions.

Characteristics of NDM-1-producing Escherichia coli isolates that belong to the successful and virulent clone ST131.

An NDM-1 carbapenemase-producing Escherichia coli isolate of sequence type 131 (ST131) that belonged to phylogenetic group B2 was obtained from a patient with a urinary tract infection who returned to the United States after a recent hospitalization while visiting India. NDM-1-producing E. coli ST131 had significantly more virulence factors than NDM-1-producing E. coli ST101, previously isolated from a patient in Canada. The presence of NDM ß-lactamases in a very successful and virulent E. coli sequence type is of concern.

Dissemination of an Enterococcus Inc18-Like vanA plasmid associated with vancomycin-resistant Staphylococcus aureus.

Of the 9 vancomycin-resistant Staphylococcus aureus (VRSA) cases reported to date in the literature, 7 occurred in Michigan. In 5 of the 7 Michigan VRSA cases, an Inc18-like vanA plasmid was identified in the VRSA isolate and/or an associated vancomycin-resistant Enterococcus (VRE) isolate from the same patient. This plasmid may play a critical role in the emergence of VRSA. We studied the geographical distribution of the plasmid by testing 1,641 VRE isolates from three separate collections by PCR for plasmid-specific genes traA, repR, and vanA. Isolates from one collection (phase 2) were recovered from surveillance cultures collected in 17 hospitals in 13 states. All VRE isolates from 2 Michigan institutions (n = 386) and between 60 and 70 VRE isolates (n = 883) from the other hospitals were tested. Fifteen VRE isolates (3.9%) from Michigan were positive for an Inc18-like vanA plasmid (9 E. faecalis [12.5%], 3 E. faecium [1.0%], 2 E. avium, and 1 E. raffinosus). Six VRE isolates (0.6%) from outside Michigan were positive (3 E. faecalis [2.7%] and 3 E. faecium [0.4%]). Of all E. faecalis isolates tested, 6.0% were positive for the plasmid, compared to 0.6% for E. faecium and 3.0% for other spp. Fourteen of the 15 plasmid-positive isolates from Michigan had the same Tn1546 insertion site location as the VRSA-associated Inc18-like plasmid, whereas 5 of 6 plasmid-positive isolates from outside Michigan differed in this characteristic. Most plasmid-positive E. faecalis isolates demonstrated diverse patterns by PFGE, with the exception of three pairs with indistinguishable patterns, suggesting that the plasmid is mobile in nature. Although VRE isolates with the VRSA-associated Inc18-like vanA plasmid were more common in Michigan, they remain rare. Periodic surveillance of VRE isolates for the plasmid may be useful in predicting the occurrence of VRSA.

Impact of strain type on detection of toxigenic Clostridium difficile: comparison of molecular diagnostic and enzyme immunoassay approaches.

A multicenter clinical trial assessed the performance of the Cepheid Xpert C. difficile assay on stool specimens collected from patients suspected of having Clostridium difficile infection (CDI). A total of 2,296 unformed stool specimens, collected from seven study sites, were tested by Xpert C. difficile enrichment culture followed by cell culture cytotoxicity testing of the isolates (i.e., toxigenic culture with enrichment) and the study sites' standard C. difficile test methods. The methods included enzyme immunoassay (EIA), direct cytotoxin testing, and two- and three-step algorithms using glutamate dehydrogenase (GDH) screening followed by either EIA or EIA and an in-house PCR assay. All C. difficile strains were typed by PCR-ribotyping. Compared to results for toxigenic culture with enrichment, the sensitivity, specificity, and positive and negative predictive values of the Xpert assay were 93.5, 94.0, 73.0, and 98.8%, respectively. The overall sensitivity of the EIAs compared to that of enrichment culture was 60.0%, and the sensitivity of combined GDH algorithms was 72.9%; both were significantly lower than that of Xpert C. difficile (P < 0.001 and P = 0.03, respectively). The sensitivity of the EIA was significantly lower than that of the Xpert C. difficile assay for detection of ribotypes 002, 027, and 106 (P < 0.0001, P < 0.0001, and P = 0.004, respectively, Fisher's exact test), and the sensitivity of GDH algorithms for ribotypes other than 027 was lower than that for Xpert C. difficile (P < 0.001). The Xpert C. difficile assay is a simple, rapid, and accurate method for detection of toxigenic C. difficile in unformed stool specimens and is minimally affected by strain type compared to EIA and GDH-based methods.

Mupirocin resistance among methicillin-resistant Staphylococcus aureus-colonized patients at admission to a tertiary care medical center.

All patients admitted to our tertiary care hospital from 1 December 2007 to 10 June 2008 were screened for methicillin (meticillin)-resistant Staphylococcus aureus (MRSA) nasal colonization, and the isolates were tested for mupirocin susceptibility by using Etest. Mupirocin resistance (MR) was noted to occur in 3.4% of MRSA carriers, and high-level MR was noted to occur in 0.62% of carriers.

Draft Genome Sequence of Clinical Isolate Alcaligenaceae sp. Strain 429.

Here, we present the 3.53-Mb genome for Alcaligenaceae sp. strain 429, isolated from a patient with unknown etiology. While the 16S rRNA gene most closely resembles Paenalcaligenes species, average amino acid identity (AAI) analysis did not meet the threshold to classify our strain as a species of this family.

Culture-Negative intracerebral abscesses in children and adolescents from Streptococcus anginosus group infection: a case series.

We report the use of 16S ribosomal RNA gene amplification and sequencing to diagnose culture-negative intracerebral abscesses in younger patients. These 3 cases demonstrate the optimal application of gene sequencing from direct specimens for patients with negative culture results compromised by antibacterial therapy but histories highly suggestive of acute bacterial infection.