Rapid Sensitivity Testing Research Articles

Direct inoculation method for identification and antimicrobial susceptibility testing using matrix-assisted laser desorption ionization-time of flight mass spectrometry and both the Vitek 2 and MicroScan Walkaway 96 Plus systems

The aim of our study was to evaluate a protocol utilizing serum separator tubes (SST) to facilitate a faster, cost-effective, direct method for rapid sensitivity testing and identification of positive blood cultures. Spiked cultures were inoculated into either Becton Dickinson (BD) BACTECTM Aerobic Plus or Anaerobic/F bottles containing sterile human blood. Bottles were immediately processed when positive. A parallel study using patient isolates was used in which bacteria were pelleted by SST from positive blood cultures. For identification, a portion of the pellet was tested by matrix-assisted laser desorption/ionization as described by the manufacturer. MicroScan panels and Vitek 2 results were compared. Categorical agreement was used as comparison to standard subculture and/or polymerase chain reaction methods. No discordant identifications were observed, and 86% generated a successful identification when compared to subculture methods. For the Vitek 2, we observed a 99% essential agreement when compared to the subculture method. For the MicroScan Walkaway, we observed 94.9%, 97.4%, and 100% categorical agreement for MIC panels 53, 38, and MICroSTREP Plus 2, respectively. Turnaround times were reduced from 4 hours for identification and 11 hours for antimicrobial sensitivity testing. We conclude that the SST method results in timelier, actionable results for antimicrobial stewardship initiatives.

168. Creation and Internal Validation of a Clinical Predictive Model for Fluconazole Resistance in Patients with Candida Bloodstream Infection

BackgroundIDSA guidelines on candidemia recommend fluconazole as first-line therapy in patients considered low risk for fluconazole resistant infections. However, there is currently no mechanism to determine risk of resistance, and most community hospitals cannot perform rapid sensitivity testing, leading to prolonged use of echinocandin therapy. This study aims to develop a clinical predictive model to identify patients at low risk for fluconazole resistance where first-line use of fluconazole therapy would be acceptable without requiring resistance testing.MethodsWe performed a retrospective cohort analysis of all hospitalized adult patients with a positive blood culture for Candida spp. from 2013 to 2018. Fluconazole resistance was determined using Sensititre™ YeastOne™ YO9 AST Plate, with cutoffs defined for each Candida species based on Clinical and Laboratory Standards Institute performance standards for antifungal testing (M60) in all patients. Using backwards stepwise regression, we developed a multivariable logistic regression model to identify factors associated with fluconazole resistance in patients in Candida bloodstream infection, including only variables with clinical plausibility and p < 0.1 in bivariable analysis. Stepwise regression was performed on bootstrapped samples to test individual variable stability and estimate confidence intervals. We used graphs of observed vs expected values to assess model performance across the probability spectrum.ResultsWe identified 539 patients with Candida bloodstream infection from 2013–2018, of which 13.4% (72/539) were fluconazole resistant. Increased risk of fluconazole resistance was associated with age (1.12 [1.01, 1.24]), bacterial septicemia (2.14 [1.20, 3.79]), receipt of previous azole therapy (5.47 [2.92, 10.26]), bone marrow transplant (2.63 [1.31, 5.29]), and myelodysplastic syndrome (3.13 [1.14, 8.60]). The model predicted fluconazole sensitivity well (c-statistic 0.788) and all the variables were stable (Figure 1).Figure 1. Graph comparing observed versus expected probability of fluconazole resistance. Bars included on the top parameter of the graph indicate the number of individuals, illustrating the distribution of the sample. ConclusionThe presented model provides a potential tool for identifying the 80% of patients at low enough risk for fluconazole resistance to receive empiric therapy with azoles and reduce use of echinocandins.Disclosures Margaret A. Olsen, PhD, MPH, Merck (Grant/Research Support)Pfizer (Consultant, Grant/Research Support) Dustin Stwalley, MA, AbbVie Inc (Shareholder)Bristol-Myers Squibb (Shareholder) Andrej Spec, MD, MSCI, Astellas (Grant/Research Support)Mayne (Consultant)Scynexis (Consultant)

Editorial: Old Problems and New Solutions in Pediatric Pulmonology

The series on pediatric pulmonology continues in this issue of the Journal, with four manuscripts that illustrate the new problems of our burgeoning speciality [1–4]. These are how the management of old problems (in this case TB) is being transformed by cutting edge science [1]; how the application of new technologies are creating challenging problems (congenital lung disease) [2]; and how new technologies are transforming the lives of children (neuromuscular disease and NIV) and taking mechanical ventilation, what used to be the prerogative of intensive care into the home, transforming the prognosis of children [3, 4]. However, as we shall see, the more the speciality advances, the more the basic truths we learned as students remain the bedrock of our practice. Old disease, new technology: TB, the captain of the men of death, used to be simple – the tuberculin skin test, sputum (or other biological sample) microscopy and culture, and evidence based treatment with quadruple therapy for 2 mo, and rifampicin and isoniazid for a further 4 mo. Problem solved, even though diagnostics and determining sensitivities might take weeks – treatment could confidently be started while waiting. In children, admittedly diagnosis often had to be on clinical suspicion, because it was difficult to obtain samples. Enter the Dragon! Or rather, multidrug-resistant TB, extremely drug-resistant TB and totally drug resistant TB [5]. Perspectives have had to change rapidly; now we need rapid diagnosis and rapid sensitivity testing, for fear of starting drugs to which the organism is resistant, effectively but inadvertently proposing a single agent regime which will lead to worse problems of drug resistance. The problem has been made worse with the advent of HIVand the consequent worsening of the manifestations of TB. The modern approach is firstly to use novel tests to obtain specimens, such as sputum induction which can be taken in very young babies, and the string test. The second approach is newer microscopy and culture techniques, and specific molecular diagnostics, which are reviewed [1]. Molecular tests not merely detect MTB rapidly in sputum or gastric aspirates, but also allow drug sensitivities to be determined, a major management advance. The future will undoubtedly include molecular handprints on blood samples, as sophisticated techniques become cheaper and more accessible. New technology, new problems: Increased monitoring of pregnant women with ultrasound scanning, and increasingly MRI, has identified abnormalities which previously passed us by. Congenital lung malformations come into just this category. In this issue, a simple clinical classification of congenital thoracic malformations (CTM), which is applicable preand post-natally, is described. However, description is one thing, evidence based management is another. How should you counsel a woman with a fetus with a large CTM at 20 wk of the pregnancy? If the baby is born well, what further imaging should be done and when? What is the risk of complications, and should well babies be submitted to surgery to reduce the risk? And when should surgery be performed? Finally, the biggest elephant in the room, what is the risk of primary lung malignancy in a baby with a CTM? High risk groups can be delineated, but most babies with CTMs are low risk. * Andrew Bush A.Bush@rbht.nhs.uk

WITHDRAWN: Rapid sensitivity testing of mycobacterium tuberculosis using the mycobacteria growth indicator tube system (MGIT)

WITHDRAWN: Rapid sensitivity testing of mycobacterium tuberculosis using the mycobacteria growth indicator tube system (MGIT)

Advances in diagnosis of tuberculosis.

The diagnosis of childhood tuberculosis is acknowledged to be an imprecise process since bacteriological confirmation is available in only 30-40% of cases. Newer developments in diagnosis of tuberculosis include use of fluorescent stains for smears, newer systems for radiometric detection of mycobacteria, rapid sensitivity testing using firefly bioluminescence, liquid chromatographic analysis of mycolic acids, immunodiagnostics for M. tuberculosis specific antigens and the impact of molecular diagnostics with amplification methods. The search for simple, reliable test for early stages of the disease (in particular TB meningitis) still continues.

Tuberculosis symposium: emerging problems and promise.

Between 1985 and 1991, 39,000 cases of tuberculosis occurred in excess of those expected based on previous trends. Immigration from high-prevalence countries, coinfection with human immunodeficiency virus (HIV), and outbreaks in congregative facilities are most responsible for the increase. Coincident with the increase in tuberculosis, outbreaks of multidrug resistant (MDR) tuberculosis have occurred. Clinical and epidemiologic data support nosocomial transmission. MDR tuberculosis occurred late in the course of HIV infection and was refractory to treatment. Compounding the problems of rising incidence and increasing resistance was the sudden recognition of shortages of antituberculous drugs. The problems currently posed by tuberculosis require new approaches to diagnosis and rapid sensitivity testing as well as assuring an adequate supply of licensed drugs and development of new drugs. A number of steps have been taken by governmental agencies to assure that the challenge is met.

Potential for local and systemic bacterial infection in some occupational groups in Benin City, Nigeria

Many Third World countries may not have adequate facilities for rapid sensitivity testing of antibiotics as an aid to diagnosis and chemotherapy. It may therefore be valuable to relate bacterial carriage on the skin to type of work a person does. Given areas of skin in workers from 10 occupational groups were sampled. The bacteria obtained were analyzed after growth on appropriate media. The sensitivity profiles of potential pathogens isolated from these groups, as well as of those (Staphylococcus aureus only) isolated from patients with certified infections, were carried out and the results were analyzed. Staphylococcus aureus constituted the most widely and frequently isolated potential pathogen. Proteus mirabilis, Escherichia coli, and Klebsiella species were also frequent colonizers of skin. There was a statistical relationship between work type and overall prevalence of bacteria on skin (p less than 0.01). Most isolates of the work groups were highly sensitive to gentamicin and cefuroxine but not to penicillin G, ampicillin, and trimethoprim plus sulfamethoxazole; isolates from infected persons were generally more resistant than were the community-acquired ones. A relationship may exist between the types of bacteria carried on the skin and the type of work in which a person is engaged.

Use of a Radiometric Technique for Rapid Sensitivity Testing of Mycobacteria in Scotland: The First Year's Experience

We report the first year's experience of the use of a radiometric technique for sensitivity testing of mycobacterial isolates in Scotland. The techniques (using the Bactec 460 instrument) was much quicker than conventional methods (for example the mean time to obtain results for 60 strains of M.tuberculosis was 14.4 days, compared with 44.9 days for conventional methods). There was good agreement between results obtained by the two methods. Preliminary results also indicated the value of the radiometric technique for rapid isolation of mycobacteria from clinical samples (mean of 10.6 days with the radiometric technique compared with 26.7 days using egg media) although for optimal recovery, both techniques should be used in parallel.

Use of a Radiometric Technique for Rapid Sensitivity Testing of Mycobacteria in Scotland: The First Year's Experience

We report the first year's experience of the use of a radiometric technique for sensitivity testing of mycobacterial isolates in Scotland. The techniques (using the Bactec 460 instrument) was much quicker than conventional methods (for example the mean time to obtain results for 60 strains of M.tuberculosis was 14.4 days, compared with 44.9 days for conventional methods). There was good agreement between results obtained by the two methods. Preliminary results also indicated the value of the radiometric technique for rapid isolation of mycobacteria from clinical samples (mean of 10.6 days with the radiometric technique compared with 26.7 days using egg media) although for optimal recovery, both techniques should be used in parallel.

Comparison of a rapid enzyme-linked immunosorbent assay test and the Gram stain for detection of group B streptococcus in high-risk antepartum patients

Early-onset neonatal sepsis with group B streptococci is a major problem in the management of high-risk obstetrics. Intrapartum treatment of the colonized mother reduces neonatal acquisition; however, many high-risk patients are delivered before culture results are available. This study prospectively evaluated a new enzyme-linked immunosorbent assay and the Gram stain for their accuracy in rapid detection of group B streptococci in 131 high-risk patients. Twenty positive cultures for group B streptococci were identified in the study population and were used as the control for test comparisons. The enzyme-linked immunosorbent assay test was 60% sensitive, whereas the Gram stain was 45% sensitive. The enzyme-linked immunosorbent assay showed an increase in sensitivity as the colony count increased; however, two cases of severe neonatal sepsis occurred in patients with low colony counts and both had enzyme-linked immunosorbent assay negative results. In conclusion, the need for a rapid sensitive test for group B streptococci detection still exists.

Nerve trophic effects: an in vitro assay for factors involved in regulation of protein synthesis in regenerating amphibian limbs.

We have developed a rapid sensitive test for factors that mimic the trophic effects of nerves by maintaining normal rates of protein synthesis in denervated forelimb blastemata of adult newts (Notophthalmus viridescens). Rates of protein synthesis in secondary blastemata are similar. However, after they are denervated and explanted into organ culture the rates of protein synthesis first increase and later fall below control values. Similar changes occur after denervation in vivo. The alterations in the rates of protein synthesis are prevented by adding to the culture medium aqueous extracts from brains of adult newts or chicken embryos. The active material is either a peptide or a protein.

Repair replication of DNA in the intact animal following treatment with dimethylnitrosamine and with methyl methanesulphonate, studied by fractionation of nuclei in a zonal centrifuge

To relate repair of lesions in DNA with carcinogenesis, it is necessary to study repair in the intact animal under conditions which will and will not induce cancer. The methods used to study the replication stage of repair in isolated cells are not suitable for use in the intact animal. A method is presented which depends on the fact that during cell replication the nuclei enlarge, and may be separated from nuclei of non-replicating cells by rate zonal centrifugation on a sucrose gradient in a zonal rotor. Thus incorporation of [ 3H]thymidine as a result of de novo synthesis of DNA in replicating nuclei can be separated from incorporation due to repair synthesis in non-replicating nuclei. Treatment of animals with dimethylnitrosamine or with methyl methanesulphonate produced a ‘repair-type’ profile, which contrasted with that given by liver nuclei from untreated animals, or from animals in which DNA synthesis had been reduced by treatment with cycloheximide, a compound which is not known to cause direct damage to DNA. Evidence is presented which suggests that the method is a rapid sensitive test for the occurrence of repair replication of some kind in the liver of the intact animal.

RAPID LATEX-SCREENING TEST FOR DETECTION OF FIBRIN/FIBRINOGEN DEGRADATION PRODUCTS IN URINE AFTER RENAL TRANSPLANTATION

Urine samples from eighty-two healthy individuals and repeated samples from sixteen recent renal-transplant recipients were assayed for fibrin/fibrinogen degradation products (F .D .P.) using a one-stage latex slide agglutination test sensitive to 2 μg. per ml. of fibrinogen. The 100 normal urine samples were negative while 143 of 451 transplant urines contained detectable levels of F.D.P. Apart from their association with the phase of recovery from acute tubular necrosis in the days immediately following transplantation, raised urinary F.D.P. were found in 9 out of 11 episodes of clinically recognised graft rejection; the appearance of F.D.P. in the urine normally preceded the other features of rejection by 1-5 days. Reversal of graft rejection and long-term stable renal function were associated with negative urine tests. This simple rapid sensitive test for urinary F.D.P. could prove useful in the management of renal-graft recipients.

Rapid Sensitivity Testing in the Prevention of Sepsis From Genitourinary Instrumentation

Rapid Sensitivity Testing in the Prevention of Sepsis From Genitourinary Instrumentation

The Prophylactic Use of Chloramphenicol in Transurethral Resections of the Prostate Gland

No AccessJournal of Urology1 Feb 1956The Prophylactic Use of Chloramphenicol in Transurethral Resections of the Prostate Gland D.M. Appleton and Burton A. Waisbren D.M. AppletonD.M. Appleton More articles by this author and Burton A. WaisbrenBurton A. Waisbren More articles by this author View All Author Informationhttps://doi.org/10.1016/S0022-5347(17)66813-7AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail © 1956 by The American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetailsCited byWarren J, Muncie H, Bergquist E and Hoopes J (2018) Sequelae and Management of Urinary Infection in the Patient Requiring Chronic CatheterizationJournal of Urology, VOL. 125, NO. 1, (1-8), Online publication date: 1-Jan-1981.Chodak G and Plaut M (2018) Systemic Antibiotics for Prophylaxis in Urologic Surgery: A Critical ReviewJournal of Urology, VOL. 121, NO. 6, (695-699), Online publication date: 1-Jun-1979.C.M.K. (2018) Editorial CommentJournal of Urology, VOL. 121, NO. 6, (698-699), Online publication date: 1-Jun-1979.Berger S and Nagar H (2018) Antimicrobial Prophylaxis in UrologyJournal of Urology, VOL. 120, NO. 3, (319-322), Online publication date: 1-Sep-1978.Gonzalez R, Wright R and Blackard C (2018) Prophylactic Antibiotics in Transurethral ProstatectomyJournal of Urology, VOL. 116, NO. 2, (203-205), Online publication date: 1-Aug-1976.Mcguire E (2018) Antibacterial Prophylaxis In Prostatectomy PatientsJournal of Urology, VOL. 111, NO. 6, (794-798), Online publication date: 1-Jun-1974.Wear J and Haley P (2018) Transurethral Prostatectomy Without AntibioticsJournal of Urology, VOL. 110, NO. 4, (436-440), Online publication date: 1-Oct-1973.Wilson F, Shumaker E, Fentress V and Lerner A (2018) Epidemiologic Aspects of Postoperative Sepsis in a Urologic Practice (with a Note Concerning Antibacterial Prophylaxis)Journal of Urology, VOL. 105, NO. 2, (295-300), Online publication date: 1-Feb-1971.Lacy S, Drach G and Cox C (2018) Incidence of Infection after Prostatectomy and Efficacy of Cephaloridine ProphylaxisJournal of Urology, VOL. 105, NO. 6, (836-839), Online publication date: 1-Jun-1971.Genster H and Madsen P (2018) Urinary Tract Infections Following Transurethral Prostatectomy: With Special Reference to the Use of AntimicrobialsJournal of Urology, VOL. 104, NO. 1, (163-168), Online publication date: 1-Jul-1970.McLin P, Fisher R and Hinman F (2018) Rapid Sensitivity Testing in the Prevention of Sepsis From Genitourinary InstrumentationJournal of Urology, VOL. 100, NO. 6, (787-791), Online publication date: 1-Dec-1968.Miller A, Scott F and Scott R (2018) An Evaluation of Antibiotics Prior to ProstatectomyJournal of Urology, VOL. 92, NO. 6, (711-713), Online publication date: 1-Dec-1964.Maluf N (2018) Transvesical Prostato-Adenomectomy with Primary Closure of the Bladder. II. Report on 180 Unselected CasesJournal of Urology, VOL. 82, NO. 4, (531-545), Online publication date: 1-Oct-1959. Volume 75Issue 2February 1956Page: 304-313 Advertisement Copyright & Permissions© 1956 by The American Urological Association Education and Research, Inc.MetricsAuthor Information D.M. Appleton More articles by this author Burton A. Waisbren More articles by this author Expand All Advertisement PDF downloadLoading ...