Evaluation of Abbott ID NOW COVID-19 POC test performance characteristics and integration in the regional health network workflows to improve health care delivery.

With the recent global surge of SARS-CoV-2 Delta variant, there continues to be high demand for COVID-19 diagnostic testing. Abbott ID NOW is a rapid, CLIA-waived, COVID-19 diagnostic test ideally suited for use in urgent care settings or where access to diagnostic testing is limited. In this study we describe the results of rigorous validation of ID NOW and post-implementation study of POC test utilization patterns within community hospitals and clinics. Performance of ID NOW was validated by comparison of the results from 207 consecutive, paired, specimens tested on the ID NOW and on the m2000/Alinity m platforms. Once validated, ID NOW devices were placed for clinical use at four regional hospitals and clinics. We found that the ID NOW and m2000/Alinity m positive and negative percent agreement were 94.5% (95% CI, 85.1% to 98.1%) and 99.3% (95% CI, 96.4% to 99.9%), respectively. As of August 2021, a total of 2,301 tests were performed by ID NOW at individual regional network sites. The population tested consisted of 55.5% White and 42.9% Black patients, with Black patients presenting predominantly in the hospitals, while White patients were more evenly distributed between hospital and clinic sites. Disease prevalence observed among patients tested by ID NOW (12.3%) was aligned with overall prevalence seen at regional sites (11.3%). In summary, the ID NOW test can provide rapid and accurate results in a variety of near-to-patient and POC settings. If used correctly, it could serve as a valuable diagnostic tool to enable equal access to care and improve healthcare delivery within large health network systems.

Practical considerations in the laboratory diagnosis of bacterial enteric infections.

Diarrheal diseases caused by bacterial pathogens are important causes of morbidity in the United States, and considerable laboratory resources are spent to detect these enteric pathogens. This article reviews recent developments in the detection and identification of Campylobacter spp, enterohemorrhagic Escherichia coli, and Clostridium difficile, and outlines cost-effective strategies for use of stool cultures.

Rapid, direct antibiotic susceptibility testing of blood culture isolates using the Abbott Avantage system.

The Abbott Avantage (AV) is an updated version of the MS-2 system that provides antibiotic-susceptibility results in four to six hours. Although the system compared favorably with reference methods in several laboratory evaluations, little information exists regarding its performance with inocula obtained directly from blood cultures. The authors compared AV and a modified disk-diffusion test using standardized inocula obtained directly from the blood culture bottles for 58 isolates (46 patients). All isolates were also tested by the National Committee for Clinical Laboratory Standards standard disk-diffusion method, using inocula obtained from subcultures of the positive bottles. AV results for 553 antibiotic tests agreed with the direct disk results in 92.6% of the tests, and the agreement with the standard disk results was 88.2%. The concordance between direct and standard disk results was 93.5%. There were 2.2% very major, 1.8% major, and 7.8% minor discrepancies between results obtained with direct AV and standard disk methods. False sensitivity of Klebsiella pneumoniae to ampicillin and carbenicillin and induced clindamycin resistance in staphylococci were noted with AV. When one considers only the clinically meaningful antibiotic-organism combinations, direct AV is an acceptable, rapid alternative to direct disk susceptibility testing.

Clinical and bacteriologic evaluation of BACTEC resin-containing blood culture medium.

In a retrospective study of 1,143 blood culture sets, BACTEC aerobic (6B) and osmotically stabilized (8B) media were compared individually with resin-containing (16B) medium for the isolation of bacteria from the blood of patients receiving antimicrobial therapy. The 16B medium was found to detect significantly more positive cultures than either 6B (P less than 0.01) or 8B (P less than 0.001). For 22 of 25 isolates of Staphylococcus aureus from 18 patients, 16B medium provided the only means of recovery. All but one of these patients were receiving appropriate antimicrobial therapy, and 16 of 18 had a previous blood culture set positive for S. aureus that did not include a 16B bottle. There was no evidence of a change in antimicrobial therapy in response to a 16B positive culture in these patients. No significant increase in the recovery of other gram-positive or gram-negative bacteria or decrease in the time to radiometric detection of positive cultures as a result of using 16B medium was noted.

Evaluation of modified MicroScan screening tests for high-level aminoglycoside resistance in Enterococcus faecalis.

Enterococcus faecalis strains that are refractory to aminoglycoside-penicillin synergistic killing can be predicted by their ability to grow in high concentrations of aminoglycoside (2,000 mg/L) or by disk diffusion tests using high content aminoglycoside disks. Forty-eight well-characterized clinical isolates of E. faecalis were used to evaluate recently reformulated gentamicin and streptomycin synergy screening tests on both overnight and rapid MicroScan (MS) Pos MIC panels (Baxter, West Sacramento, CA). The results obtained with the MS screening tests were compared with those from modified agar disk diffusion results. Discrepancies were resolved by an in-house broth microdilution method. The MS overnight tests detected 25 of 25 (100%) gentamicin high-level resistant strains and 23 of 24 (96%) streptomycin high-level resistant strains. No false high level resistance was found with the MS overnight tests. The MS rapid tests detected 100% of the gentamicin and 100% of the streptomycin high-level resistant strains, but one isolate was falsely high-level resistant to gentamicin (96% specific). The reformulated MS synergy screening tests were acceptable alternatives to disk diffusion for detection of high level aminoglycoside resistance in E. faecalis.

Disc diffusion method to screen for high-level resistance to clindamycin and erythromycin in the Bacteroides fragilis group.

High-level clindamycin resistance in Bacteroides species was investigated by measuring zone sizes surrounding 2 micrograms clindamycin and 60 micrograms erythromycin discs, using a nonstandardized disc diffusion method, and by determining minimal inhibitory concentrations (MIC). The absence of a zone of inhibition surrounding either disc was predictive for all isolates having high-level resistance to both antibiotics (MIC greater than 256 micrograms/ml), characteristic of macrolide-lincosamide-streptogramin (MLS) cross-resistance. Although zone size could not be used as an absolute predictor of MIC, a clindamycin zone diameter of less than 17 mm was suggestive of strains with a moderate level of clindamycin resistance (MIC greater than or equal to 8 micrograms/ml), regardless of erythromycin zone size. Disc diffusion testing using a combination of clindamycin and erythromycin discs can be a useful screening method for detection of clindamycin-resistant Bacteroides species, occurring either alone or as part of the MLS resistance phenotype.

Primary pulmonary infection caused by Mycobacterium terrae complex.

The Mycobacterium terrae complex, consisting of three saprophytic species, M. terrae, M. nonchromogenicum, and M. triviale, rarely causes human disease. Only six cases of respiratory infection involving the complex have been documented worldwide. A case of primary pulmonary disease in a previously healthy young woman caused by M. terrae complex is described.

Aureobacterium resistens sp. nov., exhibiting vancomycin resistance and teicoplanin susceptibility.

Two similar strains of a coryneform bacterium were isolated from human clinical material. Both strains were resistant to vancomycin but susceptible to teicoplanin. Detailed biochemical, chemotaxonomical, and molecular genetic investigations revealed that both isolates were members of a hitherto undescribed species of genus Aureobacterium. The name Aureobacterium resistens sp. nov. is proposed for the new bacterium and the type strain is CCUG 38312.

Hepatitis C virus genotyping: clinical implications and methods.

Hepatitis C virus (HCV) chronically infects at least 1% of the world's population and is a leading cause of end-stage liver disease. HCV displays a remarkable degree of genomic diversity, with the six major genotypes and numerous subtypes differing in geographic distribution. The ability of this virus to cause persistent infections is a direct result of its genomic plasticity and the evolution of quasispecies within an infected individual. HCV genotype has emerged as an important factor both in predicting a sustained response to, and in determining the duration of, antiviral therapy. Although a variety of methods have been used for genotyping HCV, nucleotide sequencing of a phylogenetically informative region remains the gold standard.

Detection and typing of hepatitis C virus.

For more than two decades prior to the discovery of the hepatitis C virus (HCV), posttransfusion non-A, non-B (NANB) hepatitis was thought to have a viral etiology. In 1989, the virus was finally identified through a unique application of molecular cloning techniques by investigators at the Centers for Disease Control, and the Chiron Corporation (1). In a reversal of the usual sequence of events, HCV was identified and defined before its existence was substantiated through tissue culture growth, electron microscopic observation, or serologic detection. Molecular cloning of HCV preceded the use of any of the conventional methods of viral identification and serologic detection then evolved from the blind immunoscreening of millions of clones with serum from a patient who had NANB hepatitis (2). The peptide expressed in a single reactive clone (5-1-1) served as the basis for the first Food and Drug Administration (FDA)-licensed diagnostic test for detection of antibodies to HCV (3).

Impact of viral load testing on patient care.

Quantitative human immunodeficiency virus (HIV) type 1 RNA tests have been essential tools in increasing our understanding of HIV pathogenesis and antiretroviral therapy. The plasma HIV RNA level is among the most powerful predictive tests in modern medicine for disease progression and has rapidly become the standard of practice for guiding clinicians in initiating, monitoring, and changing antiretroviral therapy. In this article the scientific rationale and clinical indications for viral load testing in HIV infection are reviewed.

Laboratory diagnosis of tuberculosis: past, present, and future.

Resurgence of tuberculosis justifies extraordinary efforts to expedite TB diagnosis and susceptibility testing. This demands that laboratory support expand to a "second generation" of methods and procedures, including rapid availability of fluorochrome smears of concentrated specimens, faster techniques for detection (e.g., the BACTEC radiometric broth system and microcolony detection), quicker identification (e.g., high-pressure liquid chromatography, nonisotopic genetic probes), more rapid susceptibility testing methods (e.g., BACTEC), and reporting of these results as critical values. Guidelines have been established for turnaround time for results of smears, TB organism identification, and susceptibility testing to usual first-line drugs. A "third generation" of laboratory techniques soon will make testing not only more effective but also more efficient. These methods include direct testing of respiratory specimens through nonisotopic genetic probes as well as nucleic acid amplification techniques utilizing polymerase chain reaction (PCR) and other molecular procedures. These new procedures and protocols place heavy demands on laboratory test volume, technologist time and costs. For the healthcare system or clinical laboratory without the resources to deal with these new demands, referral of TB specimens represents a reasonable alternative, as long as transport is adequate to meet current CDC and other guidelines for turnaround time.

Pseudo-outbreak of Legionella pneumophila serogroup 8 infection associated with a contaminated ice machine in a bronchoscopy suite.

OBJECTIVE: To investigate the marked increase noted over an 8-month period in the number of Legionella pneumophila isolates recovered from bronchoalveolar lavage fluid specimens obtained during bronchoscopy in our healthcare system. SETTING: Bronchoscopy suite that serves a 580-bed tertiary care center and a large, multisite, faculty practice plan with approximately 2 million outpatient visits per year. METHODS: Cultures of environmental specimens from the bronchoscopy suite were performed, including samples from the air and water filters, bronchoscopes, and the ice machine, with the aim of identifying Legionella species. Specimens were filtered and acid-treated and then inoculated on buffered charcoal yeast extract agar. Serogrouping was performed on all isolates recovered from patient and environmental samples. RESULTS: All L. pneumophila isolates recovered from patients were serogroup 8, a serogroup that is not usually recovered in our facility. An epidemiologic investigation of the bronchoscopy suite revealed the ice machine to be contaminated with L. pneumophila serogroup 8. Patients were exposed to the organism as a result of a recently adopted practice in the bronchoscopy suite that involved directly immersing uncapped syringes of sterile saline in contaminated ice baths during the procedures. At least 1 patient was ill as a result of the pseudo-outbreak. Molecular typing of isolates recovered from patient and environmental samples revealed that the isolates were indistinguishable. CONCLUSIONS: Extensive cleaning of the ice machine and replacement of the machine's water filter ended the pseudo-outbreak. This episode emphasizes the importance of using aseptic technique when performing invasive procedures, such as bronchoscopies. It also demonstrates the importance of reviewing procedures in all patient areas to ensure compliance with facility policies for providing a safe patient environment.

Posaconazole treatment for Apophysomyces elegans rhino-orbital zygomycosis following trauma for a male with well-controlled diabetes.

We report a case of rhino-orbital zygomycosis in a 43-year-old male with well-controlled diabetes mellitus. The patient initially received liposomal amphotericin B, but the infection continued to progress, so posaconazole treatment was begun and eventually led to the cure of his infection. The causative agent was identified as Apophysomyces elegans, an emerging cause of zygomycosis in immunocompetent hosts.

Laboratory diagnosis of hepatitis C.

In 1989 the hepatitis C virus was cloned, some 20 years after the first suggestion that hepatitis C virus(es) (HCV) existed. Since that time there has been rapid development of serological tests for detection of antibody to HCV and molecular tests for detection, quantitation, and characterization of HCV RNA. The development and performance characteristics of these test methods are reviewed and their implications for diagnosis, prognosis, and monitoring patients on therapy are discussed.

Branched DNA signal amplification for direct quantitation of nucleic acid sequences in clinical specimens.

In this chapter I have reviewed the development of bDNA as a method for quantitation of nucleic acid targets and the application of this technology to the study of infectious diseases and cell biology. The ability to quantify viral nucleic acids in clinical specimens has led to a better understanding of the pathogenesis of chronic viral infections such as HIV-1, HCV, and HBV. The information provided by these methods can also be important in the management of patients with these infections. The prognostic value of a single baseline HIV-1 RNA level rivals that surgical staging procedures for cancer, which are among the most powerfully predictive tests in medicine (Mellors et al., 1996). These methods have been used to assess rapidly the effects of antiviral therapy, which has both expedited the development of antiviral drugs and improved the management of patients with HIV-1 and HCV infections. bDNA has several characteristics that distinguish it from the quantitative target amplification systems, including better tolerance of target sequence variability, more direct measurement of target, simpler sample preparation, and less sample-to-sample variation. However, the first- and second-generation bDNA assays lacked sensitivity compared with the target amplifications systems. The changes incorporated into the third-generation assays have effectively increased the signal-to-noise ratio to such a high level that the analytical sensitivity of system 8 bDNA approaches that of PCR. In theory, bDNA can be made even more sensitive by increasing both the sample volume and the signal-to-noise ratio. Nonspecific hybridization can be further reduced by finding more effective blockers for the solid phase or by redesigning the amplifier molecule or the solid phase itself. The increased sensitivity may create new applications for the technology in filter and in situ hybridization assays.

Major outer membrane protein of Legionella pneumophila carries a species-specific epitope.

A monoclonal antibody (LP3IIG2) directed against a species-specific epitope of Legionella pneumophila is available from Genetic Systems Corp., Seattle, Wash., for use as a diagnostic reagent. Outer membrane protein-rich fractions were prepared from L. pneumophila serogroups 1 to 8 by treatment of cell envelopes with 2% Triton X-100. Immunoblots of sodium dodecyl sulfate-polyacrylamide gels demonstrated that each membrane fraction contained two bands that reacted with LP3IIG2. The monoclonal antibody bound preferentially to a 26,000-molecular-weight band that appears to result from modification of the 29,000-molecular-weight major outer membrane protein.

An alternative strategy for infection control of anesthesia breathing circuits: a laboratory assessment of the Pall HME Filter.

Contaminated breathing systems have been responsible for nosocomial upper respiratory tract and pulmonary infections in patients undergoing general anesthesia. The current infection control guidelines for anesthesia breathing circuits require single-patient use or high-level disinfection of breathing tubes, y-connector, and reservoir bag. An alternative infection control strategy has been suggested that incorporates placement of a microbial filter downstream from the y-connector between the circuit and the patient. This laboratory study assessed the capacity of the Pall HME Filter as a bidirectional barrier to transmission of bacteria between the y-connector of an anesthesia circle breathing system and a test lung. The investigators modified a sterile circle system to allow aerosolization of a suspension of 10(9) Micrococcus luteus over 5 h into the inspiratory limb proximal to the y-connector or downstream from the filter into the test lung. Cultures indicated that the Pall HME Filter placed between the y-connector and the test lung completely prevented transmission of bacteria in both directions. The results of this study suggest that the Pall HME Filter could be used as an effective microbial barrier between the anesthesia circle breathing system and the patient as part of an alternative strategy for infection control.