Clinical And Laboratory Standards Institute Recommendations Research Articles

Evaluation of Broth Disk Elution Method to Determine Colistin Resistance in Klebsiella pneumoniae and Escherichia coli Strains.

The reference broth microdilution (rBMD) method for the determination of colistin resistance is very laborious and time consuming, and many manual errors can occur. There are also limitations in detection of colistin heteroresistance. Therefore, alternative methods with satisfactory performance are required for routine laboratory work. In our study, the colistin broth disk elution (CBDE) method recommended by the Clinical and Laboratory Standards Institute (CLSI) for the detection of colistin resistance in routine applications was compared with rBMD. The compatibility and error rates of the method were evaluated and its usability in routine laboratory studies was examined. Eighty-nine multidrug resistant Klebsiella pneumoniae and five Echerichia coli strains isolated from various clinical specimens were included in the study. Identification of strains and antibiotic susceptibility tests were performed with MALDI-TOF MS (bioMerieux, France) and Vitek-2 (bioMerieux) system. Minimum inhibitory concentration (MIC) was studied in 0.125 - 128 mg/L dilution range by using polystyrene microplate and colistin sulfate salt according to ISO-standard (20776-1) recommendations for the reference BMD test. The CBDE method was performed according to the CLSI recommendations. Isolates with MIC ≤ 2 mg/L were considered susceptible, while isolates with MIC > 2 mg/L were considered resistant according to EUCAST recommendations. The performance of the CBDE method was evaluated according to ISO criteria (Categorical agreement > 90%; major error and very major error rates < 3%). Categorical agreement for all 58 and 36 isolates found to be resistant and susceptible, respectively, by rBMD was found to be 100% with CBDE test. Since < 1 and > 4 µg/mL values could not be determined with the CBDE method, essential agreement (EA) could not be calculated. No major or very major errors were detected. Our results showed that the performance of the CBDE test is good when compared to the rBMD method. According to our data, we believe that the CBDE method can be used in routine laboratories for the detection of colistin resistance.

Efecto antimicrobiano de curcumina sobre Enterococcus faecalis, Escherichia coli, Staphylococcus aureus y Candida albicans

Introducción: Debido al desarrollo de resistencia de los microorganismos a múltiples fármacos, se han realizado investigaciones exhaustivas de agentes terapéuticos derivados de fuentes naturales, como la curcumina. La curcumina (diferuloilmetano) es un compuesto fenólico, principal curcuminoide presente en la especie Curcuma longa L. En virtud de sus múltiples propiedades farmacológicas (antibacterianas, antifúngicas y antiinflamatorias) ha sido de gran interés para los científicos en los últimos años. El objetivo de este estudio fue evaluar el efecto antimicrobiano de la curcumina a través de la concentración mínima inhibitoria (CMI) sobre cepas de Enterococcus faecalis, Escherichia coli, Staphylococcus aureus y Candida albicans.Método: Se evaluó la actividad antibacteriana in vitro de la curcumina contra E. faecalis (ATCC 51299), E. coli (ATCC 25922) y S. aureus (ATCC 25923), siguiendo el protocolo de acuerdo con las recomendaciones del Clinical and Laboratory Standards Institute (CLSI) en su documento M-07-A8. La actividad antifúngica in vitro de la curcumina contra C. albicans (ATCC 26790) se evaluó siguiendo el protocolo de acuerdo con las recomendaciones del CLSI en su documento M27-A.Resultados: Los valores de la CMI de la curcumina fueron de 125 μg/ml, 31.2 μg/ml, 31.2 μg/ml y 125 μg/ml para E. faecalis, E. coli, S. aureus y C. albicans, respectivamente.Conclusión: Los resultados de este estudio revelaron que la curcumina en bajas concentraciones tiene efecto antimicrobiano sobre cepas de E. faecalis, E. coli, S. aureus y C. albicans.

2048. Antibiogram Use in Wisconsin Nursing Homes

BackgroundA 2014 survey demonstrated that fewer than 10% of Wisconsin (WI) Nursing Homes (NHs) used an antibiogram. In 2016, the Centers for Medicare & Medicaid Services released regulations requiring NHs to track and report their antibiotic-related outcomes. The impact these regulations will have on the development and use of antibiograms in NHs is unknown.MethodsTo characterize antibiogram use in WI NHs, a mixed-methods approach was used consisting of two statewide surveys, a combination of semi-structured interviews with key NH personnel, and a structured survey administered to providers in a sample of facilities using an antibiogram. Answers to questions included on statewide surveys administered in 2014 and 2018 were used to assess change in antibiogram use over time. Semi-structured interviews with key NH personnel focused on antibiogram development and dissemination. Structured surveys of providers focused on their awareness of antibiogram existence and the extent to which it influenced their prescribing behavior. A copy of the antibiogram was obtained from some facilities to assess consistency with Clinical and Laboratory Standards Institute (CLSI) recommendations.ResultsAntibiogram use in WI NHs increased from 9.3% in 2014 to 32.5% in 2018. The majority of antibiograms were not facility-specific, primarily due to inadequate numbers of isolates at individual facilities. Most facilities reported that antibiogram tools were updated annually, and most made an effort to disseminate them to prescribers. However, 30% of surveyed prescribers reported being unaware of the existence of an antibiogram and only 40% reported it influenced their prescribing decisions. Review of antibiograms provided by NHs revealed that all were created using the traditional “drug-bug” format; however, none were fully compliant with CLSI recommendations.ConclusionAntibiogram use in WI NHs increased significantly between 2014 and 2018. The majority of antibiograms used in WI NHs are not based on facility-specific data. A substantial number of providers are unaware of the existence of an antibiogram in their facility and only a minority felt that it impacted their prescribing decisions. More research is needed on how to increase antibiogram utility in NHs.Disclosures All authors: No reported disclosures.

Comparison of three phenotypic methods for the screening of carbapenem resistance among clinical isolates of Enterobacteriaceae

Background: The global use, misuse, and abuse of broad-spectrum antibiotics coupled with failure of development of newer effective antibiotics have led to the rapid spread of carbapenemase producing Gram-negative Enterobacteriaceae. The lack of capacity for effective diagnosis results in increased morbidity, prolonged hospitalization, suboptimal treatment leading to treatment failure, and increased healthcare cost. Aims/objectives: We set out to determine the best method(s) for the phenotypic screening of carbapenem resistance among the species of Enterobacteriaceae at University of Maiduguri Teaching Hospital (UMTH). Materials and Methods: We screened all patients admitted into various wards/units of UMTH over a 6-month period to isolate Enterobacteriaceae. We used an interviewer-administered questionnaire to obtain some basic information from the patients. We confirmed the species of Enterobacteriaceae using Microbact Gram-negative 24E test kit. All confirmed isolates were screened for carbapenem resistance with Meropenem and Ertapenem antibiotic discs (10 μg, Oxoid, UK) according to the Clinical and Laboratory Standards Institute (CLSI) guideline. Minimum inhibitory concentration (MIC) using Etest of Imipenem (Biomeriux) was also determined based on CLSI recommendations. Modified Hodge test method was considered as a gold standard for confirmatory test. The three methods were compared with the gold standard. Results: We isolated 225 Enterobacteriaceae from 225 patients. Klebsiella pneumoniae had the highest proportion of 73 (32.4%). The sensitivity of the different methods in increasing order was 95.7% for Meropenem disk (10 μg), 100% for Ertapenem disk (10 μg), and 100% for Imipenem MIC. Conclusion: In view of cost and availability, the Ertapenem disc (10 μg) method can be used for the screening of carbapenem-resistant Enterobacteriaceae. For the routine screening of carbapenem resistance Enterobacteriaceae in our clinical laboratories, the Ertapenem disc (10 μg) method is recommended.

Антибіотикорезистентність клінічних штамів Enterococcus faecalis у хірургічних стаціонарах України: результати багатоцентрового дослідження (2011-2015)

Мета роботи — вивчити антибіотикорезистентність клінічних штамів Enterococcus faecalis, виділених у пацієнтів, госпіталізованих у хірургічні стаціонари в різних регіонах України.&#x0D; Матеріали і методи. Досліджено 87 273 клінічних штами E. faecalis, виділені від пацієнтів, госпіталізованих у хірургічні відділення 47 багатопрофільних стаціонарів у м. Києві та 24 областях України у 2011—2015 рр. Вивчено чутливість штамів E. faecalis до 34 антибіотиків (пеніцилін, ампіцилін, амоксицилін, оксацилін, ампіцилін/сульбактам, амоксицилін/клавуланат, цефазолін, цефалексин, цефуроксим, цефоперазон, цефотаксим, цефтріаксон, цефтазидим, цефепім, іміпенем, меропенем, гентаміцин, амікацин, нетилміцин, еритроміцин, кларитроміцин, азитроміцин, лінкоміцин, кліндаміцин, тетрациклін, доксициклін, ванкоміцин, офлоксацин, лефлоцин, норфлоксацин, гатифлоксацин, ципрофлоксацин, пефлоксацин, лінезолід) відповідно до рекомендацій Інституту клінічних та лабораторних стандартів США (Clinical and Laboratory Standards Institute (CLSI)).&#x0D; Результати та обговорення. У досліджених хірургічних стаціонарах 37 % штамів E. faecalis були резистентними до тестованих антибіотиків. Найактивнішими щодо штамів E. faecalis були лінезолід, ванкоміцин, меропенем, лефлоцин та іміпенем. Високу частоту резистентності відзначено до цефалексину (56,4 %), пеніциліну (47,9 %), цефуроксиму (47,4 %), цефоперазону (47,0 %), норфлоксацину (43,1 %), кларитроміцину (42,6 %), цефтазидиму (41,6 %), доксицикліну (40,5 %), кліндаміцину (39,7 %), цефотаксиму (39,5 %), амікацину (38,1 %), гентаміцину (37,4 %) та азитроміцину (37,6 %). Резистентність штамів E. faecalis до ванкоміцину становила від 8,0 до 49,4 % (у середньому — 20,8 %).&#x0D; Висновки. Антибіотикорезистентність клінічних штамів E. faecalis у досліджених стаціонарах — важлива терапевтична та епідеміологічна проблема. Найбільшою активністю щодо нозокоміальних штамів E. faecalis характеризуються лінезолід, ванкоміцин, меропенем, лефлоцин та іміпенем. З огляду на постійні зміни рівня резистентності нозокоміальних штамів E. faecalis у регіонах України необхідно проводити постійний моніторинг за резистентністю до антибіотиків у кожному стаціонарі та на підставі отриманих локальних даних розробити лікарняний формуляр антибіотиків. Політику використання антибіотиків у кожному хірургічному стаціонарі слід визначати залежно від локальних даних щодо резистентності до протимікробних препаратів. Необхідно налагодити систему епідеміологічного нагляду за мікробною резистентністю на локальному, регіональному та національному рівнях.

Blood gas testing and related measurements: National recommendations on behalf of the Croatian Society of Medical Biochemistry and Laboratory Medicine.

Blood gas analysis (BGA) is exposed to risks of errors caused by improper sampling, transport and storage conditions. The Clinical and Laboratory Standards Institute (CLSI) generated documents with recommendations for avoidance of potential errors caused by sample mishandling. Two main documents related to BGA issued by the CLSI are GP43-A4 (former H11-A4) Procedures for the collection of arterial blood specimens; approved standard – fourth edition, and C46-A2 Blood gas and pH analysis and related measurements; approved guideline – second edition. Practices related to processing of blood gas samples are not standardized in the Republic of Croatia. Each institution has its own protocol for ordering, collection and analysis of blood gases. Although many laboratories use state of the art analyzers, still many preanalytical procedures remain unchanged. The objective of the Croatian Society of Medical Biochemistry and Laboratory Medicine (CSMBLM) is to standardize the procedures for BGA based on CLSI recommendations. The Working Group for Blood Gas Testing as part of the Committee for the Scientific Professional Development of the CSMBLM prepared a set of recommended protocols for sampling, transport, storage and processing of blood gas samples based on relevant CLSI documents, relevant literature search and on the results of Croatian survey study on practices and policies in acid-base testing. Recommendations are intended for laboratory professionals and all healthcare workers involved in blood gas processing.

Serovar and Antimicrobial Resistance Profiles of &lt;i&gt;Actinobacillus pleuropneumoniae&lt;/i&gt; Isolated in Japan from 2006 to 2011

Serovar and Antimicrobial Resistance Profiles of &lt;i&gt;Actinobacillus pleuropneumoniae&lt;/i&gt; Isolated in Japan from 2006 to 2011

Target site antimicrobial activity of colistin might be misestimated if tested in conventional growth media.

Cation-dependent inhibition of antimicrobial activity was reported for polymyxin antibiotics. Ca(2+) and Mg(2+) concentrations recommended by the Clinical and Laboratory Standards Institute (CLSI) for the supplementation of Müller-Hinton broth (MHB) are markedly lower than interstitial space fluid (ISF) concentrations in vivo. Hence, it was speculated that the antimicrobial activity of colistin might be overestimated if tested using conventional cation-adjusted MHB. The antimicrobial activity of colistin against n = 100 clinical isolates of Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae and Escherichia coli (n = 25 each) was evaluated by broth microdilution and, for selected isolates, by time-kill curves, in MHB without cations (MHB(ONLY)), MHB supplemented with 25 mg/L Ca(2+) and 12.5 mg/L Mg(2+) according to CLSI recommendations (MHB(CLSI)), and in MHB adjusted to 50 mg/L Ca(2+) and 20 mg/L Mg(2+) simulating ISF concentrations (MHB(ISF)). The minimum inhibitory concentration (MIC) values of colistin against the vast majority of isolates of both P. aeruginosa and A. baumannii increased significantly with higher cation concentrations. The susceptibility of K. pneumoniae isolates to colistin did not show significant changes between cation-supplemented media, while the MICs of E. coli decreased with ascending cation concentrations. These findings were confirmed in time-kill studies, where colistin killing against P. aeruginosa 1514 and A. baumannii 1485 declined with increasing cation concentrations. Contrarily, the killing of selected concentrations of colistin against K. pneumoniae 15 and E. coli 16 was enhanced in the presence of increasing cation concentrations. The present data suggest that the clinical antimicrobial activity of colistin might be misestimated in vitro if tested in conventional growth media.

Fosfomycin Susceptibility of Urinary Escherichia coli Isolates Producing Extended-Spectrum Beta-Lactamase According to CLSI and EUCAST Recommendations

The increasing rate of antibiotic resistance in Escherichia coli, the most common pathogen of urinary tract infections (UTIs), leads to difficulties in choosing appropriate antibiotic treatment and achieving treatment success. The aim of this study was to investigate in vitro activity of fosfomycin, presented as a favorable choice for the treatment of UTIs caused especially by extended-spectrum beta-lactamase (ESBL)-producing strains. A total of 244 E.coli strains, of them 118 were ESBL positive and 126 were negative, isolated from urine samples of inpatients and outpatients between May 2011-May 2012, were included in the study. Antibiotic susceptibilities of the isolates were determined by disk diffusion method (DDM) and ESBL production was confirmed by double-disc diffusion method according to the CLSI (Clinical and Laboratory Standards Institute) recommendations. Minimum inhibitor concentration (MIC) values for fosfomycin were detected by E-test method. Fosfomycin zone diameters and MIC values of isolates were interpreted according to the breakpoints of both CLSI and EUCAST (European Committee on Antimicrobial Susceptibility Testing). Susceptibilities of ESBL positive and negative isolates to fosfomycin and other antibiotics, and the results of fosfomycin susceptibility tests obtained by different methods were compared. The correlation between fosfomycin zone diameters and MIC values was calculated. In the study, the resistance rates of ESBL-producing isolates to ciprofloxacin, trimethoprim-sulfamethoxazole, gentamicin and amikacin were detected as 67%, 51%, 51% and 19%, respectively, while those rates were as 9%, 21%, 4% and 11%, respectively in non-ESBL producers. The difference between the two groups were found statistically significant (p< 0.001). Fosfomycin resistance of ESBL-producing and non-producing isolates were 3% and 1%, respectively, indicating no significant difference between the two groups (p= 0.356). According to fosfomycin MIC breakpoints defined by CLSI, 98.3% of ESBL-producing isolates and 100% of non-producing isolates were found susceptible to fosfomycin. According to EUCAST recommendations 98.3% of ESBL-producing isolates and 99.2% of non-producing isolates were found susceptible to fosfomycin. There was no significant difference between ESBL-positive and -negative strains according to CLSI and EUCAST recommendations (p= 0.233 and p= 0.611, respectively). When the methods were compared with each other, there were significant differences between DDM and CLSI-MIC or EUCAST-MIC (p= 0.033 and p= 0.049, respectively) and between CLSI-MIC and EUCAST-MIC (p< 0.001). There was a weak reverse linear correlation between fosfomycin zone diameters and MIC values (r= -0.138, p= 0.032). It was concluded that fosfomycin which had a high activity against ESBL-producing isolates was an appropriate alternative antibiotic in the treatment of UTIs.

Antibiogram compliance in University HealthSystem Consortium participating hospitals with Clinical and Laboratory Standards Institute guidelines

The degree of compliance with antibiogram guidance among University HealthSystem Consortium (UHC) hospitals was analyzed. The UHC Pharmacy Council Pharmacy Practice Advancement Committee conducted a survey to evaluate hospital policies regarding the generation, reporting, and utilization of antibiograms among UHC hospitals. The survey was distributed via a UHC online survey tool to pharmacy directors at 237 UHC hospitals. Responses were collected from April 13 to May 14, 2010. Of the 237 hospitals to which surveys were sent, 49 hospitals (21%) from 28 states submitted survey responses. Forty-eight hospitals reported that they routinely generated antibiograms, and 36 reported that they adopted all or most of the standards recommended by the 2009 guidelines on antibiograms published by the Clinical and Laboratory Standards Institute (CLSI). The compliance rates to the four key CLSI recommendations were as follows: 98% reported data at least annually, 89% eliminated duplicate isolates, 83% did not include surveillance isolates, and 64% required at least 30 isolates for each reported species. Thirty-eight hospitals had an antimicrobial stewardship program; 35 of them formally reviewed antibiograms and 19 implemented new programs based on the antibiogram data. In 16 hospitals, formulary changes were made as a consequence of antibiogram results. In 30 hospitals, pharmacists had significant involvement in compiling, reviewing, and reporting antibiograms. Among respondents from 47 UHC hospitals, the compliance rates to four key CLSI recommendations for antibiograms ranged from 64% to 98%. Respondents from 30 hospitals reported significant involvement of pharmacists in compiling, reviewing, and reporting antibiograms.

A Pilot Survey of Carbapenem-ResistantEscherichia coliandKlebsiella pneumoniaeMediated byK pneumoniaeSerine Carbapenemases in a Regional Referral Hospital in British Columbia

A Pilot Survey of Carbapenem-Resistant<i>Escherichia coli</i>and<i>Klebsiella pneumoniae</i>Mediated by<i>K pneumoniae</i>Serine Carbapenemases in a Regional Referral Hospital in British Columbia

Frequency of vancomycin-resistant Enterococci isolated from blood cultures from 2008 to 2010

Enterococci are important hospital-acquired pathogens. The most commonly isolated species of the genus, Enterococcus faecalis and Enterococcus faecium are the third to fourth-most prevalent nosocomial pathogens worldwide. The aim of this study was to determine the frequency of resistance to vancomycin and other antimicrobial agents of Enterococcus spp strains isolated from blood cultures of hospitalized patients. During the three-year period, from 2008 to 2010, 132 strains of Enterococcus spp isolated from blood cultures of hospitalized patients were tested for their susceptibility to ampicillin, vancomycin, gentamycin (high-level resistance), erythromycin, chloramphenicol, teicoplanin, ciprofloxacin by disc diffusion method according to the Clinical and Laboratory Standards Institute recommendations. Susceptibility of vancomycin resistant E. faecium to the same antibiotics and to linezolid, quinopristin/dalfopristin and tigecyclin was determined using VITEK system. Resistance to vancomycin was detected in 21 (15.9%) Enterococcus spp strains. The percentage of resistance to other antimicrobial agents varied from 23. l% for chloramphenicol to 81.3% for ciproflxacin. All vancomycin resistant enterococci were identified as E. faecium and belonged to phenotype VanA. The resistance to other antibiotics was very high, except for linezolid and quinopristin/dalfopristin (4.7%). The high-level aminoglycoside resistance was 87.6% for gentamycin and 95.2% for streptomycin. All isolates were resistant to ampicillin, teicoplanin and ciprofloxacin. The detected high frequency of multidrug-resistant isolates among vancomycin resistant enterococci is of great importance and suggests the need for further monitoring of susceptibility in order to take adequate measures to prevent and control spreading of resistant strains.

Systematic review of antibiograms: A National Laboratory System approach for improving antimicrobial susceptibility testing practices in Michigan.

Public health surveillance is often dependent on sentinel testing performed in clinical microbiology laboratories, and recognition of emerging/ unusual antimicrobial resistance is especially challenging. We obtained cumulative antibiograms from hospitals to determine whether clinical laboratories recognized unusual resistance or reported antimicrobials inappropriate for various bacterial species, as measured before and after public health laboratory (PHL) educational and technical-support interventions. We compared cumulative antibiogram data from 81 clinical laboratories servicing 86 hospitals in Michigan from 2000 through 2005 with a standardized checklist derived from Clinical and Laboratory Standards Institute (CLSI) antimicrobial susceptibility testing (AST) documents. We considered the reporting of unlikely percent-susceptible results and/or inappropriate antimicrobials serious errors, and we calculated error rates for each data year. We used CLSI-recommendation compliance as a measure to determine whether laboratories were implementing changes. Ninety-five of 239 (28%) cumulative antibiograms examined had one or more serious errors. The annual number of cumulative antibiograms with serious errors did not change radically (range: 10-13); however, when expressed as a percentage of cumulative antibiograms received, the occurrence of these errors declined from 59% in 2000 to 19% in 2005. The reporting of misleading or dangerous antimicrobial-organism combinations occurred less frequently than the reporting of unlikely percent-susceptible results. Compliance with new CLSI recommendations did not improve significantly. AST is complex and nuanced. PHL programs can provide resources, guidance, and technical support to help clinical microbiologists differentiate questionable AST results from true emerging antimicrobial resistance.

Lack of Transferability of Results between Procalcitonin Assays

In a recent issue of Clinical Chemistry , De Wolf et al. described an evaluation of the new Procalcitonin (PCT) assay from Roche, performed according to CLSI (Clinical and Laboratory Standards Institute) recommendations, compared with the widely accepted PCT assay on the Brahms Kryptor analyzer (Brahms) (1). We recently carried out an analogous study on a Cobas e411 (Roche Diagnostics)(2) and reached some different conclusions. We found no transferable results between the Elecsys Brahms PCT (Cobas) and PCT-TRACE (Kryptor) when we compared 152 samples from the same number of different patients. A regression analysis demonstrated the heteroscedasticity of the results as well as the lack of normality of the residuals. Passing-Bablock nonparametric analysis showed …

Assessing the Quality of Glucose Monitor Studies: A Critical Evaluation of Published Reports

In recent years, a large number of studies have been published on the performance of glucose monitors. The quality of these reports is not known. We searched the PubMed database for performance evaluations of handheld glucose monitors published from August 2002 to November 2006. Relevant articles were compared to 20 recommendations from the Standards for Reporting Diagnostic Accuracy (STARD) and 18 recommendations from the Clinical and Laboratory Standards Institute (CLSI). A total of 52 reports met our inclusion criteria and were reviewed. None (0%) of the reports conformed to all 38 STARD and CLSI recommendations. The range of compliance to these recommendations varied widely (median 53%; range 21%-84%). Only 1 study of the 52 reported following a CLSI recommendation for checking reference test results. Fewer than half (42%) of the reports contained STARD-recommended statements regarding how and when comparative measurements were performed. None of the glucose monitor reports from our review conformed to all STARD and CLSI recommendations. Our finding that the average rate of compliance to recommendations was low suggests that many of the researchers did not follow published recommendations for study design, methodology, and reporting and that study quality and conclusions may have been affected. Future studies evaluating the performance of glucose monitoring systems should be carefully designed and follow published recommendations for methodological and reporting quality.