FilmArray Gastrointestinal Research Articles

Zoonotic Pathogens Isolated from an Introduced Population of Red Swamp Crayfish (Procambarus clarkii) in Tenerife (Canary Islands, Spain)

The red swamp crayfish (Procambarus clarkii) is a widely distributed invasive species that is listed in the Delivering Alien Invasive Species Inventory for Europe. Native to North America, it has been introduced to numerous regions, such as the Canary Islands, Spain. Previous studies have confirmed the role of this crayfish in the maintenance of several foodborne pathogenic bacteria. Therefore, the aim of this study was to analyze the main zoonotic bacterial and parasitic pathogens present in a P. clarkii population introduced to the island of Tenerife, Canary Islands, and to assess the potential risk to public health and native fauna. A total of 22 crayfish from Tenerife were analyzed using Biofire FilmArray Gastrointestinal Panels and culture–PCR methods. The results show the presence of Plesiomonas shigelloides, Shigella/enteroinvasive Escherichia coli, enteropathogenic Escherichia coli, Salmonella ser. Enteritidis, Salmonella ser. Typhimurium, and Salmonella ser. Typhi. These results demonstrate the presence of a variety of pathogenic bacteria in the red swamp crayfish in Tenerife that represent a significant concern in terms of public health and conservation. Implementing educational campaigns to inform the community about the risks associated with handling and consuming contaminated crayfish, as well as initiatives for the restoration of the contaminated ecosystem, are necessary to prevent the transmission of the foodborne pathogens.

Assessment of the FilmArray Gastrointestinal Pathogen PCR Panel at a Tertiary Cancer Center

Background: The FilmArray gastrointestinal (GI) pathogen panel (BioFire Diagnostics, Salt Lake City, UT) is a multiplex PCR assay for syndromic diagnosis of infectious gastroenteritis. This highly sensitive assay has been widely adopted as a preferred testing modality for infectious diarrhea among hospitalized patients. However, in the era of diagnostic stewardship, concerns have been raised that this approach risks unexpected findings of questionable significance. Following an increase in GI pathogen panel testing, the infection control department reviewed results among hospitalized patients at different stages of admission. Methods: From October 2022 to May 2023, we retrospectively reviewed all GI pathogen panels sent in a large tertiary cancer hospital. Count of tests ordered and positivity trends were studied by unit and organism among inpatients. We categorized an admission course into early (≤2 inpatient days) and late (≥3 inpatient days) stages and compared results across these stages. Finally, we compared reproducibility of multiple tests sent during a single admission. Results: From October 2022 to May 2023, a total of 2,763 tests were sent across the institution with 2,113 tests from inpatient units. Tests were most commonly sent on the Pediatrics and Hematology -Oncology inpatient units and together these units accounted for 60% of tests. These two units also had the highest rate of test positivity and together accounted for 60% of positive tests among hospitalized patients. The most frequently detected organisms were Norovirus (7%) and Enteropathogenic E. coli (3%) (Figure 1). Patients tested in the early stage of hospital admission were more likely to have a positive result for any target (93/509, 18.3%) compared to patients tested in the late stage (202/1604, 12.5%). Patients with a positive test in the early stage of admission were less likely to have a subsequent negative test (3/93, 3%) compared to patients who were positive in late stage of admission (39/202, 19.3% (Figure 2). Conclusions: Our findings suggest that the utility of the FilmArray GI PCR panel is highest in the early stages of a patient’s hospital admission. Testing of patients hospitalized ≥3 days is likely to be inappropriate. These findings support implementation of diagnostic stewardship standards on when syndromic testing for potentially infectious diarrhea is appropriate. Figure 1: FilmArray gastrointestinal pathogen PCR panel positivity by organism. Figure 2: FilmArray gastrointestinal pathogen PCR panel positivity by organism comparing early vs late stage of hospital admission.

Multiplex Gastrointestinal Panel Testing in Hospitalized Patients With Acute Diarrhea in Thailand.

Multiplex gastrointestinal (GI) panel testing is widely used for outpatient diagnosis of diarrhea. However, the clinical practicality of multiplex testing in hospitalized diarrheal subjects has not yet been thoroughly elucidated. We enrolled hospitalized subjects with acute diarrhea. The subjects' stool samples were collected in triplicate; 1 sample was tested using traditional diagnoses, and the other 2 were tested using Allplex (AP) and FilmArray (FA) GI panel testing. Clinical data were reviewed and analyzed. Of the 199 subjects, 92 (46.5%) were male, and the mean age was 66.3 years. The median (interquartile range) onset of diarrhea was 6 (2--14) days after hospitalization. One hundred fifty-one patients (75.9%) had sepsis, and 166 (83.4%) had received prior or were receiving current antimicrobial therapy. Positive stool cultures were obtained from 4/89 (4.5%), and Clostridioides difficile toxin gene tests were positive in 14/188 (7.4%) patients. AP and FA multiplex tests were positive for GI pathogens in 49/199 (24.6%) and 40/199 (20.1%), respectively. The target most frequently detected by AP was Aeromonas spp. Both assays commonly detected enteropathogenic E. coli (EPEC), C. difficile toxin gene, and Salmonella spp.; neither assay detected pathogens in 75.4% and 79.9%. Fever (odds ratio [OR], 2.05; 95% CI, 1.08-3.88; P = .028), watery diarrhea (OR, 2.69; 95% CI, 1.25-5.80; P = .011), and antimicrobial therapy (OR, 2.60; 95% CI, 1.18-5.71; P = .018) were independent factors associated with the negative multiplex test result. Multiplex GI panel testing effectively detects enteric pathogens associated with diarrhea in hospitalized subjects. The etiology remains undiagnosed in >75% of cases. Factors contributing to negative test results should be considered before implementing the tests.

Diagnostic performance of a multiplexed gastrointestinal PCR panel for identifying diarrheal pathogens in children undergoing hematopoietic stem cell transplant.

Diarrhea is a common complication of hematopoietic stem cell transplantation (HSCT) and is associated with substantial morbidity, but its etiology is often unknown. Etiologies of diarrhea in this population include infectious causes, chemotherapy- or medication-induced mucosal injury and graft-versus-host disease (GVHD). Distinguishing these potential causes of diarrhea is challenging since diarrheal symptoms are often multifactorial, and the etiologies often overlap in transplant patients. The objectives of this study were to evaluate whether the FilmArray gastrointestinal (GI) panel would increase diagnostic yield and the degree to which pre-transplantation colonization predicts post-transplantation infection. From November 2019 to February 2021, a total of 158 patients undergoing HSCT were prospectively included in the study. Stool specimens were obtained from all HSCT recipients prior to conditioning therapy, 28 ± 7days after transplantation and at any new episode of diarrhea. All stool samples were tested by the FilmArray GI panel and other clinical microbiological assays. The primary cause of post-transplantation diarrhea was infection (57/84, 67.86%), followed by medication (38/84, 45.24%) and GVHD (21/84, 25.00%). Ninety-five of 158 patients were colonized with at least one gastrointestinal pathogen before conditioning therapy, and the incidence of infectious diarrhea was significantly higher in colonized patients (47/95, 49.47%) than in non-colonized patients (10/63, 15.87%) (P < 0.001). Fourteen of 19 (73.68%) patients who were initially colonized with norovirus pre-transplantation developed a post-transplantation norovirus infection. Twenty-four of 62 (38.71%) patients colonized with Clostridium difficile developed a diarrheal infection. In addition, FilmArray GI panel testing improved the diagnostic yield by almost twofold in our study (55/92, 59.78% vs. 30/92, 32.61%). Our data show that more than half of pediatric patients who were admitted for HSCT were colonized with various gastrointestinal pathogens, and more than one-third of these pathogens were associated with post-transplantation diarrhea. In addition, the FilmArray GI panel can increase the detection rate of diarrheal pathogens in pediatric HSCT patients, but the panel needs to be optimized for pathogen species, and further studies assessing its clinical impact and cost-effectiveness in this specific patient population are also needed.

Utility of BioFire FilmArray Gastrointestinal Panel in the Diagnosis of Gastrointestinal Infections

Abstract Background Conventional diagnostic methods like culture and microscopy are time-consuming and have low diagnostic yield for gastrointestinal infections. New rapid molecular methods such as multiplex polymerase chain reaction (PCR) have recently been introduced for etiological diagnosis. The aim of this study was to evaluate the utility of the FilmArray gastrointestinal panel (GIP) in the diagnosis of gastrointestinal infections. Materials and Methods This is a retrospective study performed in the microbiology department of a tertiary care hospital. Stool samples were received and processed according to the manufacturer's instructions by FilmArray GIP. Stool culture and routine microscopy were also performed. Results The mean age of the 32 patients was 46 ± 24.2 years and with a male-to-female ratio of 1:1. Out of 32 stool samples received for testing by BioFire GIP, 23 samples (71.9%) were found to be positive for one or the other target. A total of 41 targets were detected from 23 positive patients, with predominant bacterial etiology (65.9%) followed by parasitic (31.7%) and viral (4.9%). Giardia lamblia was the most common (26.8%) target detected in all age groups. Additionally, in 56.5% of patients, more than one target was detected. The stool culture was positive in 2 of the 16 patients (12.5%). Conclusion The FilmArray GIP showed very good diagnostic performance compared with culture for the diagnosis of gastrointestinal infections. Further studies are needed to determine whether multiplex PCR improves patient outcomes and reduces costs.

Detection of multiple human enteropathogens in Norway rats (Rattus norvegicus) from an under-resourced neighborhood of Vancouver, British Columbia.

Urban Norway rats (Rattus norvegicus) can carry various human pathogens, and may be involved in pathogen propagation and transmission to humans. From January 31-August 14, 2021, a community outbreak of Shigella flexneri serotype 2a occurred among unhoused or poorly housed people in the Downtown Eastside neighborhood of Vancouver, British Columbia, Canada. The source could not be identified; however, patients reported contact with rats, and previous studies indicated transmission of rat-associated zoonotic pathogens among the unhoused or poorly housed residents of this neighborhood. The study objective was to determine if rats trapped in the outbreak area were carriers of Shigella spp. and other zoonotic enteric pathogens. From March 23-April 9, 2021, 22 rats were lethally trapped within the outbreak area. Colonic content was analyzed using the BioFire FilmArray Gastrointestinal (multiplex PCR) panel for human enteropathogens, which detected: Campylobacter spp. (9/22), Clostridioides difficile (3/22), Yersinia enterocolitica (5/22), Cryptosporidium spp. (8/22), Giardia duodenalis (5/22), Rotavirus A (1/22), enteroaggressive Escherichia coli (2/22), enteropathogenic E. coli (10/22), and Shigella spp. or enteroinvasive E. coli (EIEC) (3/22). An ipaH PCR assay was used for targeted detection of Shigella spp./EIEC, with five rats positive. Two samples contained insertion sites unique to S. flexneri isolated from the human outbreak. This study highlights the potential for rats to carry a broad range of human pathogens, and their possible role in pathogen maintenance and/or transmission.

B-237 Analytical and Clinical Performance Evaluation of the Panther Fusion® GI Parasite Assay (In Development)

Abstract Background Acute diarrhea from gastrointestinal (GI) infections is the leading cause of outpatient visits, hospitalizations, and loss of quality of life, with an estimated global impact of 500 million illnesses and 230 000 deaths annually. Most GI infections from bacteria, viruses, and parasites present similar symptoms, but successful treatment is dependent on accurate pathogen identification. For identification of parasites, microscopic testing is often used, but is laborious and often results in inconclusive or inaccurate diagnoses. Clinicians now rely on rapid and accurate molecular diagnostics to correctly identify the causative organism, which leads to optimal infection control and appropriate treatment. The Panther Fusion (PF) GI Parasite Assay is a multiplex qualitative real-time PCR assay that addresses the need for accurate and sensitive identification and detection of the most common parasites that are known to cause gastroenteritis: Cryptosporidium, Entamoeba histolytica, Giardia lamblia and Cyclospora cayetanensis. Methods Stool specimens collected in Cary-Blair (CB) are transferred to the AptimaTM Multitest collection tube (Hologic). Multitest tubes are loaded on Panther Fusion where nucleic acid isolation, amplification, and detection are performed. Analytical sensitivity was assessed using cell suspension of Cryptosporidium, Giardia or E. histolytica spiked in negative CB Stool (CBS) matrix and the limit of detection (LoD) was determined using probit. Since Cyclospora cayetanensis cannot be cultured, in-vitro transcribed RNA (IVT) was spiked in CBS matrix for LoD evaluation. Inclusivity was evaluated using cell suspensions for 20 Giardia and 15 E. histolytica strains spiked in CBS matrix. Cryptosporidium inclusivity was evaluated with synthetic nucleic acid. Specificity was evaluated by spiking cells suspensions or synthetic nucleic acid of various microbes in CBS in the presence or absence of GI targets. For clinical performance, 119 archived frozen stool specimens in CB and 40 contrived specimens were tested on Film Array GI Panel (BioFire) and PF GI Parasite Assay and results were compared. Results The LoD for Cryptosporidium, Giardia and E. histolytica was determined to be &amp;lt; 1 cell/mL in the Aptima Multitest tube. For C. cayetanensis, the LoD was found to be 1032 copies/mL. The PF GI Parasite Assay detected 20 strains of Giardia lamblia and 15 E. histolytica strains. In-silico and initial testing of synthetic nucleic acid demonstrated detection of 10 Cryptosporidium species. No cross-reactivity to closely related organisms or other microorganisms commonly found in the gastrointestinal tract was observed, except for cross-reactivity to Entamoeba nuttalli, which rarely infects humans. In testing of clinical remnant specimens, the PF GI Parasite Assay had a 97% PPA (35/36) for Cryptosporidium, 100% PPA (58/58) for Giardia lamblia, 100% PPA (42/42) for E. histolytica (included 40 contrived specimens) and 100% PPA (8/8) for Cyclospora with the Film Array GI Panel. Conclusion The PF GI Parasite Assay demonstrated excellent analytical and clinical performance in the detection and differentiation of Cryptosporidium, Entamoeba histolytica, Giardia lamblia and Cyclospora cayetanensis. Together with its companion Panther Fusion assays that detect bacterial and viral GI pathogens (also in development), this assay will provide a sensitive and accurate molecular tool for the automated detection of parasites in human stool.

Impact of Rapid Molecular Multiplex Gastrointestinal Pathogen Testing in Management of Children during a Shigella Outbreak.

Fecal culture for isolation and identification of Shigella may take days. The BioFire FilmArray Gastrointestinal (GI) panel (bioMérieux, France) is a PCR-based assay that detects enteric pathogens including Shigella/enteroinvasive Escherichia coli (EIEC) in about an hour. The aim of this study was to evaluate the impact of GI panel detection of Shigella in a pediatric emergency department (ED) during an outbreak. Stool samples from children with acute gastroenteritis were tested by the GI panel. Test results were either withheld in preintervention (PRE) or reported to clinicians/families in the postintervention (POST) period. The impact of the GI panel testing on patient management and outcomes was measured. Shigella/EIEC was identified by the GI panel in the PRE (n = 30) and POST (n = 21) phase. The GI panel detected more Shigella infections than did culture; six of 31 (19.4%) Shigella GI panel-positive patients who also had stool cultures were missed by culture. Azithromycin therapy was prescribed for 20% of subjects in the PRE phase and 71.4% of subjects in the POST phase (P < 0.001). Time from the clinical encounter until starting azithromycin therapy was shorter in the POST phase (n = 9), 8.25 h (range, 6.37 to 52.37 h), than in the PRE phase (n = 1), 72 h. Six subjects in the PRE phase visited additional providers compared with one in the POST phase. Prompt diagnosis of shigellosis with the GI panel may provide the opportunity for prompt antimicrobial therapy and avoid additional visits to providers due to early definitive diagnosis. Prompt diagnosis of Shigella at an ED visit may optimize patient management and reduce transmission.

Epidemiological investigations of diarrhea in children in Praia city, Cape Verde.

Diarrheal disease is a major cause of infant mortality and morbidity in Africa and results primarily from contaminated food and water sources, but its prevalence predictors in Cape Verde are not completely known. For this reason, this study aimed to identify the etiological agents of diarrhea in Cape Verdean children and assess its associated risk factors. A survey questionnaire was used, and a total of 105 stool samples from children with diarrhea aged 0-12 years at the Central Hospital of Praia (Santiago, Cape Verde) were analyzed. The analyses were carried out using Biofire FilmArray Gastrointestinal Panels. Possible risk factors for these pathogens were analyzed using logistic regression, chi-square tests, or Fisher's exact test. Among the bacteria, enteroaggregative Escherichia coli (45.71%; 95% CI: 36.71-56.70), enteropathogenic E. coli (40%; 95% CI: 30.56-50.02), Shigella/enteroinvasive E. coli (29.52%; 95% CI: 21.02-39.22), E. coli enterotoxigenic (12.38%; 95% CI: 6.76-20.24), Campylobacter sp. (10.48%; 95% CI: 5.35-1.97), Vibrio sp. (4.76%; 95% CI: 1.56-10.76), Clostridioides difficile (3.81%; 95% CI: 1.05-9.47), Vibrio cholerae (2.86%; 0.59-8.12), Shiga-like toxin-producing E. coli (2.86%; 0.59-8.12) and Salmonella sp. (0.95%; 0.02-5.19) were identified; four viruses, Rotavirus A (28.57%; 95% CI: 20.18-38.21), Sapovirus I. II. IV and V (11.43%; 95% CI: 6.05-19.11), Norovirus GI.GII (6.67%; 95% CI: 2.72-13.25) and Adenovirus F 40.41 (6.67%; 95% CI: 2.72-13.25) were also observed. All the pathogens detected in this study were found in coinfections. Significant associations with risk factors were found; specifically, having a bathroom at home reduced the risk of Campylobacter sp., having animals at home increased the risk of Shigella/EIEC infection, and drinking bottled water reduced the risk of Sapovirus infection. From the findings of this study, it can be concluded that, in Cape Verde, there is a high prevalence and diversity of pathogens among children. Our results could help to establish an adequate diagnosis and effective treatments for diarrheal disease.

531. Clinical Evaluation of the BioFire® FilmArray® Gastrointestinal (GI) Panel for use with Rectal Swab Specimens in Cary-Blair Media

Abstract Background The BioFire® FilmArray® Gastrointestinal (GI) Panel provides results for 22 bacterial, viral, and protozoan pathogens responsible for GI infection in about an hour. This test is indicated for use with stool specimens in Cary-Blair media (SCB) as a specimen type. For many patients, a stool sample can be difficult to provide during a single clinic visit, potentially delaying diagnosis and treatment. Rectal swabs in Cary-Blair (RSCB; an off-label sample type) are a more convenient and faster specimen type to collect, as collection can occur during a patient’s healthcare visit. The purpose of this study was to assess the performance of the GI Panel when testing RSCB compared to SCB. Methods Paired SCB and RSCB specimens were collected from outpatient subjects with signs of GI infection and tested in parallel using the GI Panel. All detections were confirmed using culture (for some bacterial analytes) and PCR/sequencing. Performance of the GI Panel in RSCB versus SCB specimen types was assessed using the ratios (RSCB/SCB) of sensitivities and false positive rates (FPR). Positive percent agreement (PPA) and negative percent agreement (NPA) for the GI Panel test in RSCB compared to SCB were also evaluated. Results A total of 299 paired SCB and RSCB specimens were collected and tested with the GI Panel. Detections for 17 of the 22 analytes on the GI Panel were observed in both specimen types. When comparing results from RSCB and SCB specimen types, the overall ratio of sensitivity was 0.86 and the overall ratio of FPR was 0.31. Further, overall PPA was 76.6% and overall NPA was 99.8%. Conclusion Overall, the GI Panel is sensitive and specific for the rapid detection of many of the organisms responsible for GI infection when using either specimen type, however RSCB specimens have a lower diagnostic yield (i.e. fewer detections) compared to SCB. As a result, GI Panel performance for the RSCB is characterized as less sensitive compared to performance for SCB specimens. Acknowledging these limitations, the convenience and time-to-result benefits of the RSCB specimen type may aid in the effective diagnosis and management of GI infection in outpatient settings. The BioFire FilmArray GI Panel is not cleared or approved for use with rectal swabs in Cary-Blair. Disclosures Jared Goos, PhD, bioMerieux: Employee|bioMerieux: Stocks/Bonds Crissy Neff, n/a, bioMerieux: Employee|bioMerieux: Stocks/Bonds Kristen Holmberg, n/a, bioMerieux: Employee Annie Lyons, n/a, bioMerieux: Employee Nicole Monroe, Dr. sc. nat., bioMerieux: Employee Rangaraj Selvarangan, BVSc, PhD, D(ABMM), FIDSA, F(AAM), BioFire: Grant/Research Support|Luminex: Grant/Research Support Kimberle Chapin, MD, Cepheid: Employee Bradley A. Connor, MD, BioMerieux: Advisor/Consultant Cynthia Andjelic, PhD, bioMerieux: Employee.

2011. Use of Biofire®Filmarray gastrointestinal panel on clinical decision making and infection control in a General Pediatric Department.

Abstract Background The new Biofire® Filmarray Gastrointestinal Panel (BFGI-BioMérieux, France) offers advantage against conventional cultures of gastrointestinal tract specimens with rapid detection and a broader pathogen identification. Aim of this study is to evaluate the use of BFGI and compare detection of pathogens in GI samples with conventional cultures in hospitalized children with gastroenteritis. Methods A retrospective study was conducted in a General Tertiary level Pediatric Department from Jan 2020 to Apr 2022. Children were included if an appropriate GI tract specimen was obtained for clinical evaluation and was assessed by BFGI. Results were compared with conventional cultures. Demographic, clinical, laboratory data, treatment and the effect of the BFGI on clinical decision making were analyzed. Results Fifty-eight children were included, 27(46%) females, with mean age 5.1 (IQR 9.35). Thirty-one (53%) had an underlying condition, or a prolonged hospital stay. All children had diarrhea, 44% had fever and 25% had vomits. The most common pathogens were Norovirus (8/58), Campylobacter (7/58) and Enteropathogenic Escherichia coli (EPEC, 6/58), followed by Clostridium difficile, Rotavirus and Salmonella spp. Five of the Norovirus cases were detected within a 10-day period, in children that were hospitalized for other reasons, indicating an intrahospital outbreak. In five patients there was a co-infection with 2 or more pathogens. In 35 patients a stool culture (salmonella and shigella) was performed. All cultures were negative. In 20 (57%) patients, culture results were in accordance with a negative BFGI, but in the rest 15 (42%) patients the PCR detected at least one pathogen. Only 17 patients were treated with antimicrobials, because of age &amp;lt; 3 months or the severity of disease/ comorbidities. A macrolide was prescribed in all campylobacter cases (clarithromycin, 57%, azithromycin, 43%). Conclusion In this cohort of hospitalized patients with gastroenteritis, BFGI offered a rapid and more precise result, in comparison to cultures. It helped recognize a norovirus outbreak in the department and improve the infection control measures. Finally, it assisted the clinical decision making leading to more rational and targeted antibiotic administration. Disclosures All Authors: No reported disclosures.

364. Diagnosis of Amebic Liver Abscess by a Commercial Multiplex Stool Amplification Assay. A Potentially Useful Alternative in Limited-Resources Settings.

Abstract Background Amoebic liver abscess (ALA) is caused by the protozoan parasite Entamoeba histolytica. Clinical and radiological features of ALA often mimic those of pyogenic liver abscess (PLA). Currently, differential diagnosis between ALA and PLA relys on microscopic examination, anti-amoebic IgG serology, and culture of aspirate for pyogenic organisms. Therefore, there is a need for new, rapid and more accurate microbiological methods for diagnosing ALA. Unfortunately, with few exceptions, available reports involved the use of inhouse or laboratory-tailored polymerase chain reaction (PCR) assays. We herein report our recent experience with the successful use of a commercial multiplex, nested PCR assay designed for stool, in the diagnosis of two cases of ALA. Methods Two severely ill adult Latin American migrants presented with fever, malaise, non-bloody diarrhea, abdominal pain and leukocytosis. CT scans revealed single large hypodense, inflammatory, liver cystic lesions. Results Necrotic material obtained by needle aspiration under guidance and stool samples were processed by FilmArray Gastrointestinal Panel (BioFire Diagnostics, Salt Lake City), designed to detect 13 bacterial, 5 viral and 4 parasitic pathogens, both amplified only for E. hystolitica DNA. ELISA serology for amoeba was also positive. Bacterial cultures were sterile. Treatment with Metronidazole and paromomycin resulted in complete recovery. Conclusion Analysis of liver abscess content using a commercially available, multiplex, nested PCR assay designed for stool, may represent a convenient alternative to currently available diagnostic methods, providing rapid results and allowing for immediate choosing of specific therapy targeting single pathogens on more rational basis. Since there are several commercially available multiplex PCR panels containing primers for E. histolytica, their use for evaluation of liver abscess samples has some theoretical advantages for the diagnosis of ALA, such as simplicity, ample availability, rapid processing time and capacity to exclude simultaneously several potential pathogens. Nevertheless, further testing is necessary to validate their use in liver abscess diagnosis and define their false positivity and negativity rates. Disclosures All Authors: No reported disclosures.

Clinical impact of biofire gastrointestinal panel testing for hospitalised children with acute gastroenteritis.

To investigate the clinical impact of BioFire FilmArray Gastrointestinal Panel (FGP) testing in real-life diarrhoeal episodes of hospitalised paediatric patients. Children hospitalised between October 2018 and September 2020 for whom stool specimens for FGP were submitted at the clinician's discretion were retrospectively observed. For each episode, demographics, clinical information and stool tests were collected. The clinical impact for each case was evaluated by changing the antibiotic prescription, following the result of the FGP testing. Out of 140 diarrhoeal episodes, 25 pathogens were found in 24 cases using conventional methods, whereas, FGP testing identified 75 pathogens in 56 cases (p< 0.05). The pathogens more frequently identified by FGP testing were Campylobacter, Shigella, Rotavirus, Giardia lamblia and Cryptosporidium. The clinical impact of FGP testing was observed in 17/140 (12%) diarrhoeal episodes, and higher rates in previously healthy (19%) and solid organ-transplanted children (15%). We found that using FGP testing for hospitalised children with diarrhoeal episodes could increase pathogen identification and impact clinical decisions, especially in healthy and transplant patients.

The Efficacy of the BioFire FilmArray Gastrointestinal Panel to Reduce Hospital Costs Associated With Contact Isolation: A Pragmatic Randomized Controlled Trial.

Background: Molecular syndromic panels can rapidly detect common pathogens responsible for acute gastroenteritis in hospitalized patients. Their impact on both patient and healthcare system outcomes is uncertain compared to conventional stool testing. This randomized trial evaluates the impact of molecular testing on in-hospital resource utilization compared to conventional stool testing.Methods: Hospitalized patients with acute diarrheal illness were randomized 1:1 to either conventional or molecular stool testing with the BioFire FilmArray gastrointestinal panel (FGP). The primary outcome was the duration of contact isolation, and secondary outcomes included other in-hospital resource utilization such as diagnostic imaging and antimicrobial use.Results: A total of 156 patients were randomized. Randomization resulted in a balanced allocation of patients across all three age strata (<18, 18-69, ≥70 years old). The proportion of positive stools was 20.5% vs 29.5% in the control and FGP groups, respectively (p=0.196). The median duration of contact isolation was 51 hours (interquartile range [iqr] 66) and 69 hours (iqr 81) in the conventional and FGP groups, respectively (p=0.0513). There were no significant differences in other in-hospital resource utilization between groups.Conclusions: There were no differences in in-hospital resource utilization observed between the FGP and conventional stool testing groups.

Detection of potential enteric pathogens in children with severe acute gastroenteritis using the filmarray: Results from a three - years hospital-based survey in Northern Italy

Acute gastroenteritis (AGE) are leading causes of morbidity and mortality in children. Therefore, rapid pathogens identification is needed.The AGE aetiology was investigated from 2018 to 2020 in 2,066 children in Parma (Italy) by FilmArray Gastrointestinal Panel and Enterovirus-targeting RT-PCR. Pathogens were detected in 1,162 (56.2%) stool samples from as many children; 798 (68.7%) were single and 364 (31.3%) mixed infections (68.7% vs 31.3%, P < 0.0001). Children aged 0–5 years showed the highest infection incidence (66.1%).The most frequent pathogens were Enteropathogenic Escherichia coli (EPEC; 19.14%), Clostridioides difficile (10.42%), Norovirus (10.36%), Enterovirus (9.44%), and Campylobacter (9.21%). EPEC, Campylobacter, enteroaggregative E. coli, Norovirus, and Rotavirus showed seasonality. The incidence of pathogens detected decreased between 2018 and 2020 (42.7% vs 20.8%, P < 0.0001), seemingly for the preventive measures imposed by the severe acute respiratory syndrome coronavirus-2 pandemic. A putative aetiology in half the children examined and an estimate of enteric pathogens epidemiology were assessed.

Alternative Causes of Infectious Diarrhea in Patients with Negative Tests for Clostridoides Difficile.

Hospitalized patients with diarrhea who have a negative Clostridoides difficile (C. difficile) test are not routinely evaluated for alternative causes of infectious diarrhea. This study assessed for potential infectious causes of diarrhea in hospitalized patients with an order for repeat C. difficile toxin enzyme immunoassay (tEIA) testing after an initial tEIA test was negative. For patients age ≥18 years who had a second C. difficile tEIA test ordered within 96 h after a negative tEIA test, remnant fecal specimens from the first (negative) tEIA test were evaluated using the BioFire FilmArray Gastrointestinal Panel PCR, C. difficile toxigenic culture, and culture on a blood agar plate (BAP) to identify other potential causes of infectious diarrhea. Growth of organisms on the BAP was also used to assess potential disruptions in the gastrointestinal microbiota. Among 84 remnant specimens, toxigenic C. difficile was identified in 9 (11%) by culture or PCR, while potential alternative causes of infectious diarrhea, including norovirus, rotavirus, enteropathogenic Escherichia coli, and Salmonella, were identified in 11 specimens (13%) by PCR. For the majority of patients, no infectious cause of diarrhea was identified, but 84% exhibited disrupted gastrointestinal microbiota, which may contribute to diarrhea. When a hospitalized patient has a negative C. difficile tEIA test but continues to have diarrhea, alternative infectious and noninfectious causes of diarrhea should be considered. If the patient has clinical signs and symptoms suggestive of infection or risk factors for gastrointestinal infection, laboratory testing for other etiologic agents may be appropriate.

Colonization with Gastrointestinal Pathogens Prior to Hematopoietic Cell Transplantation and Associated Clinical Implications

Infectious diarrhea following hematopoietic cell transplantation (HCT) significantly contributes to morbidity and mortality. Most HCT recipients experience diarrhea in the post-transplantation period, and infectious pathogens are frequently detected during diarrheal episodes. However, little is known about how frequently these patients are colonized with gastrointestinal (GI) pathogens before their transplantation and whether colonization predicts future diarrheal illness. We sought to determine how frequently HCT recipients are colonized with GI pathogens before HCT and the degree to which pre-HCT colonization predicts post-transplantation infectious diarrheal illness. We conducted a prospective cohort study of allogeneic and autologous HCT recipients at a single center between December 2016 and January 2019. Stool samples were collected during the week before HCT, and formed samples were evaluated for the presence of 22 diarrheal pathogens using the BioFire FilmArray GI panel. We determined the frequency with which participants were colonized with each pathogen and identified factors associated with colonization. We then determined how frequently pretransplantation colonization led to post-transplantation diarrheal infections due to the colonizing pathogen and whether colonization was associated with increased number of days of post-transplantation diarrhea during the transplant hospitalization. We enrolled 112 asymptomatic patients (allogeneic, 61%; autologous, 39%) who had a formed stool specimen before HCT, of whom 41 (37%) had a GI pathogen detected. The most commonly detected organisms were Clostridioides difficile (n=21; 19%), Yersinia enterocolitica (n = 9; 8%), enteropathogenic Escherichia coli (EPEC) (n=6; 6%), and norovirus (n = 5; 4%). Female sex and previous C. difficile infection were associated with C. difficile colonization, and having non-Hodgkin lymphoma was associated with being colonized with a diarrheal pathogen other than C. difficile. Thirteen of 21 patients (62%) with pretransplantation C. difficile colonization developed a clinical C. difficile infection post-transplantation, and 8 of 10 patients (80%) colonized with EPEC or enteroaggregative E. coli developed post-transplantation infections due to their colonizing pathogen. Pretransplantation C. difficile colonization was also associated with an increased duration of post-transplantation diarrhea (P=.048). Conversely, none of the 9 patients with pretransplantation Yersinia enterocolitica colonization developed a post-transplantation Y. enterocolitica infection. Patients admitted for HCT are frequently colonized with a diverse range of GI pathogens. Colonization with C. difficile colonization and diarrheagenic E. coli is frequently associated with post-transplantation diarrheal infections caused by these organisms, but the clinical significance of colonization with other GI pathogens is not clear.

Accuracy and comparison of two rapid multiplex PCR tests for gastroenteritis pathogens: a systematic review and meta-analysis

ObjectivesThe primary aim is to provide a summary of evidence for the diagnostic accuracies of multiplex PCR gastrointestinal (GI) panels—BioFire FilmArray and Luminex xTAG on the detection of gastroenteritis pathogens....

720. Clinical Performance of Film Array Gastrointestinal Pathogen Panel in Diarrhea

BackgroundInfective diarrhea is a common problem. Multiplex Polymerase chain reaction (PCR) based pathogen diagnostics of diarrheal stool specimens are shown to be highly sensitive and rapid as opposed to conventional diagnostics.MethodsWe analyzed the performance of a multiplex PCR test, FilmArray (FA) gastrointestinal (GI) panel, on stool specimens in patients admitted with acute and chronic diarrhea to our hospital from December 2016 to December 2019 and compared the results with conventional diagnostic tests.ResultsA total of 98 patients were analyzed, 52 were males and 9 belonged to pediatric age. 92.9% patients presented with acute diarrhea. None were HIV positive. Among 98 tested, FA GI pathogen panel was positive for at least one pathogen in 39.8% patients. The yield was low for stool culture, 7.79%. In samples tested by FA GI pathogen panel, a single pathogen was identified in 27 patients (27.5%) while multiple targets were identified in 12 patients (12.2%). Majority (76.5%) had normal stool routine. Stool routine abnormality and positive GI pathogen panel did not correlate, as only 7 patients with abnormal stool routine had a positive result in FA GI pathogen panel, while 12 patients had negative result. Among the 39 patients with positive FA GI pathogen panel, only 6 had positive stool culture result. All stool culture positive sample also had GI pathogen panel positive result. Commonest organism in stool culture was Salmonella (5) while one patient had E. coli. Commonest organism in stool FA GI pathogen panel was also Salmonella, 12 isolates as a single pathogen and 5 as one among the multiple targets identified, making a total of 17 isolates. This is followed by Enteroaggregative E. coli (EAEC- 9) and Enteropathogenic E. coli (EPEC- 5). %). Only one had virus as pathogen (norovirus), no parasitic infection was identified. Multiple pathogens were identified in 12 patients. Clostridium difficile toxin was positive in 2 in whom multiple targets were identified. Among the chronic diarrhea syndrome, none had stool culture positivity while two had positive FA GI pathogen panel results and the organisms were Campylobacter and EAEC.FA GI pathogen panel results Multiple targets that are identified ConclusionFA GI panel detects a wide array of GI pathogens, better yield and has a quick turn-around-time compared to conventional tests like stool culture.Disclosures All Authors: No reported disclosures

S0859 Clinical Significance of Positive GI Pathogens PCR Testing in IBD Patients: A Retrospective Analysis

INTRODUCTION: Gastrointestinal (GI) infection in patients with inflammatory bowel disease (IBD) is a common mimic of disease flare. Aside from Clostridioides difficile infection (CDI) there is limited data on the clinical significance of enteric infections in patients with IBD. The aim of this study is to characterize the clinical impact of non-CDI enteric infection in an IBD patient population. METHODS: A retrospective chart review was performed on adult patients with IBD seen in the University of Virginia Health System between 2015 and 2019 who underwent testing for GI infection with the FilmArray Gastrointestinal Panel (BioFire Diagnostics, Salt Lake City, UT), a polymerase chain reaction stool test (GI PCR). Patients were excluded if they tested positive for CDI at or within 30 days of the encounter. Patient demographics, IBD subtype, location of disease, medications at encounter, and laboratory data, imaging and endoscopic results at presentation were recorded. The primary outcome of interest was escalation of IBD therapy or surgery within six months. Statistical analysis included Chi-square testing and student's t-test for categorical variables. RESULTS: A total of 261 patients undergoing 437 GI PCR tests were identified. The mean age was 43 years, and the majority of patients tested were white (83%), female (56%) and had Crohn's disease (60%). Of the GI PCR tests, 59 (14%) had positive results. Hospitalization rates were similar between the groups, but positive PCR was associated with a shorter length of stay (3.3 days vs 5.3, P = 0.01). Compared to a positive GI PCR result, patients with a negative result were more likely to have a change in IBD therapy at the initial encounter (54% vs 31%, P = 0.003). However, there was no significant difference in rates of escalation of IBD therapy or surgery at six months. Secondary analysis for risk factors associated with positive GI PCR showed that patients with a positive GI PCR result were more likely to use non-steroidal anti-inflammatory drugs (NSAIDs) than those with a negative result (18.6% vs 6.9%, P = 0.006). CONCLUSION: This study supports prior data that non-CDI enteric infection does not lead to a difference in long term clinical outcomes including escalation of therapy or surgery in patients with IBD. NSAID use was associated with enteric infections in patients with IBD and merits further investigation with appropriate studies.Table 1.: Characteristics of patients with inflammatory bowel disease (IBD) who underwent stool testing with the FilmArray Gastrointestinal Pane (BioFire Diagnostics, Salt Lake City, UT) (GI PCR)Table 2.: Encounter details of patients who underwent testing with GI PCR*Table 3.: Association of GI PCR* results with clinical outcomes in IBD