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2.
J Clin Microbiol ; 61(6): e0188622, 2023 06 20.
Artículo en Inglés | MEDLINE | ID: mdl-36971571

RESUMEN

Antibacterial susceptibility testing (AST) is performed to guide therapy, perform resistance surveillance studies, and support development of new antibacterial agents. For 5 decades, broth microdilution (BMD) has served as the reference method to assess in vitro activity of antibacterial agents against which both novel agents and diagnostic tests have been measured. BMD relies on in vitro inhibition or killing of bacteria. It is associated with several limitations: it is a poor mimic of the in vivo milieu of bacterial infections, requires multiple days to perform, and is associated with subtle, difficult to control variability. In addition, new reference methods will soon be needed for novel agents whose activity cannot be evaluated by BMD (e.g., those that target virulence). Any new reference methods must be standardized, correlated with clinical efficacy and be recognized internationally by researchers, industry, and regulators. Herein, we describe current reference methods for in vitro assessment of antibacterial activity and highlight key considerations for the generation of novel reference methods.


Asunto(s)
Antibacterianos , Humanos , Pruebas de Sensibilidad Microbiana , Antibacterianos/farmacología
3.
J Clin Microbiol ; 60(10): e0221021, 2022 10 19.
Artículo en Inglés | MEDLINE | ID: mdl-35916520

RESUMEN

A vast amount of antimicrobial susceptibility test (AST) data is generated from routine testing in diagnostic laboratories for the primary purpose of guiding clinicians in antimicrobial therapy decisions for their patients. However, there is additional value for these data when they are compiled at the local, regional, national, and global levels. Cumulative AST data can be used to prepare antibiograms at the individual health care facility level. These reports can be used to gain insight into appropriate empirical therapy options prior to the availability of AST results on an individual patient's isolate. Different types of cumulative AST data reports can also be compiled at the regional, national, and global levels to estimate susceptibility rates in geographic regions, document trends in evolving microbial populations, and recognize the appearance and spread of emerging antimicrobial resistance threats. The first CLSI M39 Guideline for Analysis and Presentation of Cumulative AST Data was published in 2000. Since that time, there have been changes to AST and reporting recommendations as well as the introduction of advanced informatics technologies to analyze and present data. The 5th edition of M39 has taken into consideration these changes to assist those who analyze, present, and utilize routine antibiograms and other types of cumulative AST data reports as well as those who design information systems for the capturing and analyzing of AST data. Furthermore, antimicrobial stewardship programs (ASPs) have expanded considerably, and uses of the antibiogram by ASPs have been addressed. This minireview will remind users of the basic recommendations for analysis and presentation of antibiograms and provide new suggestions to enhance these reports.


Asunto(s)
Antibacterianos , Laboratorios , Humanos , Pruebas de Sensibilidad Microbiana , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Instituciones de Salud
4.
J Clin Microbiol ; 59(12): e0021321, 2021 11 18.
Artículo en Inglés | MEDLINE | ID: mdl-34550809

RESUMEN

The Clinical and Laboratory Standards Institute (CLSI) Subcommittee on Antimicrobial Susceptibility Testing (AST) develops and publishes standards and guidelines for AST methods and results interpretation in an annual update to the Performance Standards for Antimicrobial Susceptibility Testing (M100). This minireview will discuss changes to M100 for the 31st edition, including new and revised breakpoints and testing recommendations. New MIC and disk diffusion breakpoints are described for azithromycin (Shigella spp.), imipenem-relebactam (Enterobacterales, Pseudomonas aeruginosa, and anaerobes), and lefamulin (Staphylococcus aureus, Haemophilus influenzae, and Streptococcus pneumoniae), and disk breakpoints are described for azithromycin and Neisseria gonorrhoeae. The rationale behind revised oxacillin MIC breakpoints for select staphylococci is discussed. Updates to test methods include a method for disk diffusion using positive blood culture broth and use of linezolid to predict tedizolid susceptibility. There is clarification on which drugs to suppress on bacteria isolated from the cerebrospinal fluid and clarification on the use of a caret symbol attached to the intermediate category ("I^") to indicate those antimicrobials that concentrate in the urine.


Asunto(s)
Laboratorios , Oxacilina , Antibacterianos/farmacología , Humanos , Pruebas de Sensibilidad Microbiana , Pseudomonas aeruginosa
5.
Eur J Clin Microbiol Infect Dis ; 39(11): 2037-2044, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32577953

RESUMEN

Carbapenem-resistant Gram-negative bacilli are a major public health problem. Accurate and rapid detection of carbapenemase-producing organisms can facilitate appropriate infection prevention measures. The objective was to evaluate the performance of the RAPIDEC® CARBA NP assay (RAPIDEC), a screening assay that utilizes a pH indicator to detect carbapenem hydrolysis within 2 h. A multicenter study evaluated 306 clinical bacterial strains of Enterobacterales (n = 257) and Pseudomonas aeruginosa (n = 49). The RAPIDEC was compared to a composite reference standard-the Clinical Laboratory Standards Institute (CLSI) Carba NP assay, PCR for specific carbapenemase genes (blaKPC, blaNDM, blaOXA-48-like, blaVIM and blaIMP), and phenotypic carbapenem susceptibility testing. The assay was evaluated using two culture incubation times for the bacterial isolates: "routine"(cultures incubated 18-24 h) and "short" (cultures incubated 4-5 h). For the routine incubation, the overall percent agreement was 98.7% with a positive percent agreement (PPA) of 99.6% and a negative percent agreement (NPA) of 97.4%; there were five false positives and one false negative. For the short incubation, the overall percent agreement was 98.0% with a PPA of 98.5% and a NPA of 97.3%; there were five false positives and four false negatives. RAPIDEC results for the P. aeruginosa isolates were 100% concordant with the reference standard for both incubation times. The RAPIDEC assay is an accurate and rapid (≤ 2 h) assay for the detection of the most common carbapenemases in clinical isolates. Growth from a short incubation culture may be used to reliably detect carbapenemase production in clinical strains.


Asunto(s)
Proteínas Bacterianas/metabolismo , Enterobacteriaceae Resistentes a los Carbapenémicos/metabolismo , Pseudomonas aeruginosa/metabolismo , beta-Lactamasas/metabolismo , Programas de Optimización del Uso de los Antimicrobianos , Técnicas Bacteriológicas , Humanos , Sensibilidad y Especificidad , Estados Unidos
6.
J Clin Microbiol ; 58(5)2020 04 23.
Artículo en Inglés | MEDLINE | ID: mdl-32132195

RESUMEN

Limited treatment options contribute to high morbidity/mortality rates with carbapenem-resistant, Gram-negative bacterial infections. New approaches for carbapenemase-producing organism (CPO) detection may help inform clinician decision-making on patient treatment and infection control. BD Phoenix CPO detect (CPO detect) detects and classifies carbapenemases in Enterobacterales, Acinetobacter baumannii, and Pseudomonas aeruginosa during susceptibility testing. The clinical performance of CPO detect is reported here. Enterobacterales, Acinetobacter baumannii, and Pseudomonas aeruginosa isolates were evaluated across three sites using CPO detect and a composite reference method (RM); the latter was comprised of the modified carbapenem inactivation method and a MIC screen for ertapenem, imipenem, and meropenem. Multiplex PCR testing was also utilized for Ambler class determination. Positive and negative percentages of agreement (PPA and NPA, respectively) between CPO detect and the RM were determined. The PPA and NPA for Enterobacterales were 98.5% (confidence intervals, 96.6%, 99.4%) and 97.2% (95.8%, 98.2%), respectively. The A. baumannii PPA and NPA, respectively, were 97.1% (90.2%, 99.2%) and 97.1% (89.9%, 99.2%). The P. aeruginosa PPA and NPA, respectively, were 95.9% (88.6%, 98.6%) and 92.3% (86.7%, 95.6%). The PPA values for carbapenemase class designations for all organisms combined and Enterobacterales alone, respectively, were 95.3% (90.2%, 97.8%) and 94.6% (88.8%, 97.5%) for class A, 94.0% (88.7%, 96.6%) and 96.4% (90.0%, 98.8%) for class B, and 95.0% (90.1%, 97.6%) and 99.0% (94.4%, 99.8%) for class D carbapenemases. NPA values for all organisms and Enterobacterales alone ranged from 98.5% to 100%. CPO detect provided accurate detection and classification of CPOs for the majority of isolates of Enterobacterales, Acinetobacter baumannii, and Pseudomonas aeruginosa tested.


Asunto(s)
Antibacterianos , beta-Lactamasas , Proteínas Bacterianas/genética , Humanos , Pruebas de Sensibilidad Microbiana , beta-Lactamasas/genética
7.
J Clin Microbiol ; 57(6)2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30971460

RESUMEN

The Clinical and Laboratory Standards Institute (CLSI) has revised several breakpoints since 2010 for bacteria that grow aerobically. In 2019, these revisions include changes to the ciprofloxacin and levofloxacin breakpoints for the Enterobacteriaceae and Pseudomonas aeruginosa, daptomycin breakpoints for Enterococcus spp., and ceftaroline breakpoints for Staphylococcus aureus Implementation of the revisions is a challenge for all laboratories, as not all systems have FDA clearance for the revised (current) breakpoints, compounded by the need for laboratories to perform validation studies and to make updates to laboratory information system/electronic medical record builds in the setting of limited information technology infrastructure. This minireview describes the breakpoint revisions in the M100 supplement since 2010 and strategies for the laboratory on how to best adopt these in clinical testing.


Asunto(s)
Pruebas de Sensibilidad Microbiana/métodos , Pruebas de Sensibilidad Microbiana/normas , Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Servicios de Laboratorio Clínico/legislación & jurisprudencia , Servicios de Laboratorio Clínico/normas , Política de Salud , Humanos , Estados Unidos , United States Food and Drug Administration
8.
J Clin Microbiol ; 57(3)2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-30567744

RESUMEN

In 2019, the Clinical and Laboratory Standards Institute (CLSI) published revisions to the Enterobacteriaceae ciprofloxacin and levofloxacin breakpoints. We evaluated the performance of disk diffusion and Etest compared to that of reference broth microdilution by use of the revised breakpoints. Fifty-eight Enterobacteriaceae isolates with ciprofloxacin MICs of 0.5 µg/ml or 1.0 µg/ml on initial testing were specifically selected for evaluation. These MICs are susceptible by the 2018 breakpoints and not susceptible by the 2019 breakpoints. For ciprofloxacin disk diffusion, the categorical agreement (CA) was 46.6%, with 0 very major errors (VME), 4 major errors (ME) (21.1%), and 27 minor errors (mE) (46.6%) using the 2019 CLSI disk breakpoints. For levofloxacin, the CA was 72.4%, with 0 VME, 0 ME, and 16 mE (27.6%) using the 2019 CLSI disk breakpoints. Using an error rate-bound evaluation method, levofloxacin but not ciprofloxacin disk diffusion yielded an acceptable minor error rate of <40% for isolates with an MIC plus or minus 1 doubling dilution of the intermediate breakpoint. For Etest compared to the reference broth microdilution, the essential agreement was 100% for both ciprofloxacin and levofloxacin and the CA was 81.0% and 65.5%, respectively. No VME or ME were observed by Etest, and 11 minor errors for ciprofloxacin (19.0%) and 20 (34.5%) for levofloxacin were observed. By the error rate-bound method, the minor error rate for ciprofloxacin was acceptable, but minor error rates for levofloxacin remained outside the acceptance range (i.e., 42.6% for isolates with an MIC within 1 dilution of the breakpoint). In general, the disk diffusion and Etest methods performed well with this challenging collection of isolates, although laboratories must be aware of minor errors, particularly for isolates with results near the breakpoint.


Asunto(s)
Antibacterianos/farmacología , Ciprofloxacina/farmacología , Enterobacteriaceae/efectos de los fármacos , Levofloxacino/farmacología , Pruebas Antimicrobianas de Difusión por Disco , Farmacorresistencia Bacteriana , Pruebas de Sensibilidad Microbiana
9.
J Clin Microbiol ; 57(2)2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30282791

RESUMEN

Limited methods for colistin MIC determination are available to clinical microbiology laboratories. The purpose of this study was to evaluate the accuracy of the colistin broth disk elution (CBDE) test compared to that of broth microdilution (BMD) for identifying colistin MICs. CBDE was compared to colistin BMD using a collection of Gram-negative bacilli tested at two U.S. microbiology laboratories. The isolates tested included 121 retrospective clinical isolates, 45 prospective clinical isolates, and 6 mcr-1-positive Escherichia coli isolates. CBDE was performed with four 10-ml cation-adjusted Mueller-Hinton broth tubes per isolate, to which 0, 1, 2, and 4 colistin 10-µg disks were added, generating final concentrations in the tubes of 0 (growth control), 1, 2, and 4 µg/ml, respectively. MICs were evaluated visually and interpreted using Clinical and Laboratory Standards Institute breakpoints. Site 2 also compared CBDE to the reference broth macrodilution (BMAD) method (n = 110 isolates). Overall, CBDE yielded a categorical agreement (CA) and essential agreement (EA) of 98% and 99%, respectively, compared to the results of colistin BMD. Very major errors occurred for mcr-1-producing strains, with MICs fluctuating from 2 to 4 µg/ml on repeat testing. The results for all other isolates were in CA with those of BMD. CBDE versus BMAD had an EA of 100% and a CA of 100%. Compared to currently used techniques, CBDE is an easy and practical method to perform colistin MIC testing. Some mcr-1-producing isolates yielded MICs of 2 µg/ml by CBDE and 4 µg/ml by BMD. As such, the results for isolates with colistin MICs of 2 µg/ml by CBDE should be confirmed by the reference BMD method, and isolates with MICs of ≥2 µg/ml should be evaluated for the presence of mcr genes.


Asunto(s)
Antibacterianos/farmacología , Colistina/farmacología , Bacterias Gramnegativas/efectos de los fármacos , Pruebas de Sensibilidad Microbiana/métodos , Errores Diagnósticos/estadística & datos numéricos , Bacterias Gramnegativas/aislamiento & purificación , Infecciones por Bacterias Gramnegativas/diagnóstico , Infecciones por Bacterias Gramnegativas/microbiología , Humanos , Estudios Prospectivos , Estudios Retrospectivos , Estados Unidos
10.
J Clin Microbiol ; 56(9)2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-29976590

RESUMEN

Ceftolozane-tazobactam (C/T) is a novel beta-lactam-beta-lactamase inhibitor combination antibiotic approved by the U.S. Food and Drug Administration in 2014 for the treatment of complicated intra-abdominal infections (in combination with metronidazole) and complicated urinary tract infections. In this study, we evaluated the performance of the C/T Etest, a gradient diffusion method. C/T Etest was compared to broth microdilution (BMD) for 51 Enterobacteriaceae challenge isolates and 39 Pseudomonas aeruginosa challenge isolates at three clinical sites. Essential agreement (EA) between the methods ranged from 47 to 49/51 (92.2 to 96.1%) for the Enterobacteriaceae, and categorical agreement (CA) ranged from 49 to 51/51 (96.1 to 100.0%). EA and CA for P. aeruginosa were 100% at all sites. The C/T Etest was also compared to BMD for susceptibility testing on 966 clinical isolates (793 Enterobacteriaceae, including 167 Klebsiella pneumoniae and 159 Escherichia coli isolates, in addition to 173 P. aeruginosa isolates) collected at four clinical sites. EA between Etest and BMD was 96.9% for Enterobacteriaceae isolates and 98.8% for P. aeruginosa isolates. Within the Enterobacteriaceae, isolates from each species examined had >96% CA. For the clinical isolates, no very major errors were identified but two major errors were found (one for K. pneumoniae and one for Providencia rettgeri). By BMD, 47.0% of Enterobacteriaceae and 46.2% of P. aeruginosa challenge strains were nonsusceptible to C/T by CLSI breakpoint criteria; 8.2% of clinical Enterobacteriaceae isolates and 12.1% of clinical P. aeruginosa isolates were nonsusceptible to C/T by CLSI breakpoint criteria. In conclusion, Etest is accurate and reproducible for C/T susceptibility testing of Enterobacteriaceae and P. aeruginosa.


Asunto(s)
Antibacterianos/farmacología , Cefalosporinas/farmacología , Pruebas Antimicrobianas de Difusión por Disco/métodos , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Enterobacteriaceae/efectos de los fármacos , Pseudomonas aeruginosa/efectos de los fármacos , Tazobactam/farmacología , Pruebas Antimicrobianas de Difusión por Disco/normas , Enterobacteriaceae/aislamiento & purificación , Infecciones por Enterobacteriaceae/microbiología , Humanos , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/aislamiento & purificación , Reproducibilidad de los Resultados
11.
Clin Infect Dis ; 67(7): 1132-1138, 2018 09 14.
Artículo en Inglés | MEDLINE | ID: mdl-29796616

RESUMEN

Clinical laboratories act at the frontline of identification of infections caused by multidrug-resistant organisms, and yet the tools they apply are often woefully out of date. Incomplete adoption of current testing standards, updated breakpoints, and tests for new drugs across laboratories has been exacerbated by lack of coordination between standards development organizations (SDOs), pharmaceutical companies, susceptibility test manufacturers, and the US Food and Drug Administration. The 21st Century Cures Act includes provisions to enable alignment between these groups by (1) allowing recognition of breakpoints set by qualified SDOs; (2) publicly posting recognized breakpoints; and (3) reviewing breakpoints for necessary updates, every 6 months. Combined, these provisions will ensure more rapid recognition of current breakpoints, improving detection and management of resistant infections. Although several limitations remain, this will ultimately allow susceptibility test manufacturers to more readily update to current breakpoints.


Asunto(s)
Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Pruebas Diagnósticas de Rutina/métodos , Farmacorresistencia Bacteriana Múltiple , Pruebas de Sensibilidad Microbiana/métodos , United States Food and Drug Administration/legislación & jurisprudencia , Pruebas Diagnósticas de Rutina/normas , Política de Salud/legislación & jurisprudencia , Humanos , Laboratorios/normas , Pruebas de Sensibilidad Microbiana/normas , Estados Unidos
12.
J Clin Microbiol ; 56(5)2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29436415

RESUMEN

Antimicrobial resistance is the most pressing medical challenge of the past decade. At the front line are clinical laboratories, which are responsible for accurately reporting antimicrobial susceptibility test (AST) results to clinicians and public health authorities. The ability of the laboratory to detect resistance has been hampered by several factors. In 2016, the 21st Century Cures Act was signed into law, marking an important step toward resolving many regulatory dilemmas that hampered development and updates to commercial AST systems (cASTs). We describe the pathway and history of U.S. regulation of cASTs and outline both the rewards and unmet needs possible from the 21st Century Cures Act.


Asunto(s)
Antibacterianos/uso terapéutico , Pruebas Diagnósticas de Rutina/métodos , Política de Salud/historia , Política de Salud/legislación & jurisprudencia , Pruebas de Sensibilidad Microbiana/métodos , Pruebas Diagnósticas de Rutina/normas , Historia del Siglo XXI , Humanos , Pruebas de Sensibilidad Microbiana/normas , Estados Unidos
13.
J Clin Microbiol ; 56(4)2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29367292

RESUMEN

Effective evaluations of antimicrobial susceptibility tests (ASTs) require robust study design. The Clinical and Laboratory Standards Institute (CLSI) Subcommittee on Antimicrobial Susceptibility Testing has recognized that many published studies reporting the performance of commercial ASTs (cASTs) suffer from major design and/or analysis flaws, rendering the results difficult or impossible to interpret. This minireview outlines the current consensus of the Methods Development and Standardization Working Group of the CLSI Subcommittee on Antimicrobial Susceptibility Testing regarding best practices for systematic evaluation of the performance of an AST, including the analysis and presentation of essential data intended for publication.


Asunto(s)
Técnicas de Laboratorio Clínico/métodos , Técnicas de Laboratorio Clínico/normas , Pruebas de Sensibilidad Microbiana/métodos , Pruebas de Sensibilidad Microbiana/normas , Humanos
14.
J Clin Microbiol ; 56(3)2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29212704

RESUMEN

The performance characteristics of the ceftolozane-tazobactam (C-T) Etest (bioMérieux, Marcy l'Etoile, France), MIC test strips (MTS; Liofilchem, Italy), and disk diffusion (Hardy, Santa Ana, CA) were evaluated for a collection of 308 beta-lactam-resistant isolates of Pseudomonas aeruginosa recovered from three institutions in Los Angeles, CA. Reference testing was performed by the reference broth microdilution (rBMD) method. MIC and disk results were interpreted using Clinical and Laboratory Standards Institute breakpoints. Overall, 72.5% of the isolates were susceptible to C-T by rBMD. Etest and disk diffusion demonstrated acceptable performance, whereas MTS yielded a greater than acceptable percentage of minor errors. Categorical agreement was 96.8% for Etest, 87.0% for MTS, and 92.9% for disk diffusion. No very major errors were observed by any test, and no major errors (ME) were observed by Etest or disk diffusion. Two ME (0.9% of susceptible isolates) were observed by MTS. The incidence of minor errors was 3.2%, 12.3%, and 7.1% for Etest, MTS, and disk diffusion, respectively. Essential agreement (EA) for Etest was excellent, at 97.7%, whereas the MICs obtained by MTS tended to be 1 to 2 dilutions higher than those obtained by rBMD, with an EA of 87.0%.


Asunto(s)
Antibacterianos/farmacología , Técnicas Bacteriológicas/normas , Cefalosporinas/farmacología , Pruebas de Sensibilidad Microbiana/normas , Pseudomonas aeruginosa/efectos de los fármacos , Tazobactam/farmacología , Resistencia betalactámica/efectos de los fármacos , Humanos , Técnicas de Dilución del Indicador/normas , Pruebas de Sensibilidad Microbiana/instrumentación , Pseudomonas aeruginosa/aislamiento & purificación
15.
Clin Infect Dis ; 66(7): 1061-1067, 2018 03 19.
Artículo en Inglés | MEDLINE | ID: mdl-29099915

RESUMEN

Background: The Clinical and Laboratory Standards Institute (CLSI) revised the carbapenem breakpoints for Enterobacteriaceae in 2010. The number of hospitals that adopted revised breakpoints and the clinical impact of delayed adoption has not been explored. Methods: We performed a cross-sectional, voluntary survey of microbiology laboratories from California acute care hospitals and long-term acute care hospitals (LTAC) to determine use of revised CLSI breakpoints. Carbapenem-resistant Enterobacteriaceae (CRE) clinical isolates from a single tertiary-care hospital from 2013 to 2017 were examined. All isolates with an elevated minimum inhibitory concentration (MIC; ≥2 µg/mL) to imipenem or meropenem were tested for the presence of carbapenemase genes by polymerase chain reaction (PCR). Results: We received responses from 128 laboratories that serve 264/393 (67%) of hospitals and LTACs. Current CLSI carbapenem breakpoints for Enterobacteriaceae were used by 92/128 (72%) laboratories. Among laboratories that used current breakpoints, time to implementation varied from 0 to 68 months (mean, 41 months; median, 55 months). Application of historical breakpoints to isolates with a carbapenemase gene detected by PCR resulted in susceptibility rates of 8.9%, 18.6%, and 18.6% to ertapenem, imipenem, and meropenem, respectively. By current breakpoints, <1% of these isolates were susceptible to ertapenem or imipenem and 2.6% to meropenem. Conclusion: Clinicians and epidemiologists should be aware that use of outdated MIC breakpoints for Enterobacteriaceae remains common and can result in reports of false susceptibility to carbapenems and missed identification of carbapenemase producers. This misclassification could have consequences for patient care and infection control efforts to address carbapenemase-producing Enterobacteriaceae.


Asunto(s)
Antibacterianos/farmacología , Enterobacteriaceae Resistentes a los Carbapenémicos/aislamiento & purificación , Carbapenémicos/farmacología , Infecciones por Enterobacteriaceae/diagnóstico , Pruebas de Sensibilidad Microbiana/normas , Proteínas Bacterianas/genética , California , Enterobacteriaceae Resistentes a los Carbapenémicos/genética , Estudios Transversales , Humanos , Reacción en Cadena de la Polimerasa , Encuestas y Cuestionarios , Centros de Atención Terciaria/estadística & datos numéricos , beta-Lactamasas/genética
16.
Artículo en Inglés | MEDLINE | ID: mdl-28993338

RESUMEN

Ceftolozane-tazobactam (C/T) and ceftazidime-avibactam (CZA) MICs were evaluated for a collection of 309 beta-lactam-resistant isolates of Pseudomonas aeruginosa recovered from three institutions in the area of Los Angeles, CA. Overall, 12.0% of isolates were susceptible to imipenem, 15.9% were susceptible to meropenem, 20.7% were susceptible to piperacillin-tazobactam, 24.6% were susceptible to ceftazidime, 25.9% were susceptible to cefepime, 72.5% were susceptible to C/T, and 61.8% were susceptible to CZA. Among C/T-resistant isolates, 9.1% were CZA susceptible, whereas 36.4% of CZA-resistant isolates were susceptible to C/T.


Asunto(s)
Antibacterianos/farmacología , Compuestos de Azabiciclo/farmacología , Ceftazidima/farmacología , Cefalosporinas/farmacología , Ácido Penicilánico/análogos & derivados , Pseudomonas aeruginosa/efectos de los fármacos , Resistencia betalactámica/genética , beta-Lactamasas/genética , Cefepima , Combinación de Medicamentos , Expresión Génica , Humanos , Los Angeles , Meropenem , Pruebas de Sensibilidad Microbiana , Ácido Penicilánico/farmacología , Piperacilina/farmacología , Combinación Piperacilina y Tazobactam , Infecciones por Pseudomonas/tratamiento farmacológico , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/enzimología , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/aislamiento & purificación , Tazobactam , Tienamicinas/farmacología , beta-Lactamasas/metabolismo
18.
J Clin Microbiol ; 55(6): 1954-1960, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-28404676

RESUMEN

Eighty Gram-negative bacilli (54 Enterobacteriaceae and 26 nonfermenting Gram-negative bacilli) obtained from multiple institutions in the United States were distributed in a blinded manner to seven testing laboratories to compare their performance of a test for detection of carbapenemase production, the Carba NP test. The Carba NP test was performed by all laboratories, following the Clinical and Laboratory Standards Institute (CLSI) procedure. Site-versus-site comparisons demonstrated a high level of consistency for the Carba NP assay, with just 3/21 site comparisons yielding a difference in sensitivity (P < 0.05). Previously described limitations with blaOXA-48-like carbapenemases and blaOXA carbapenemases associated with Acinetobacter baumannii were noted. Based on these data, we demonstrate that the Carba NP test, when implemented with the standardized CLSI methodology, provides reproducible results across multiple sites for detection of carbapenemases.


Asunto(s)
Proteínas Bacterianas/análisis , Técnicas Bacteriológicas/métodos , Enterobacteriaceae/enzimología , beta-Lactamasas/análisis , Humanos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Estados Unidos
19.
Clin Infect Dis ; 64(7): 894-901, 2017 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-28362935

RESUMEN

BACKGROUND: Whole-genome sequencing (WGS) is an emerging and powerful technique by which to perform epidemiological studies in outbreak situations. METHODS: WGS was used to identify and evaluate an outbreak of OXA-232-expressing carbapenem-resistant Klebsiella pneumoniae (CRKP) transmitted to 16 patients over the course of 40 weeks via endoscopic retrograde cholangiopancreatography procedures at a single institution. WGS was performed on 32 OXA-232 CRKP isolates (1-7 per patient) and single-nucleotide variants (SNVs) were analyzed, with reference to the index patient's isolate. RESULTS: Interhost genetic diversity of isolates was between 0 and 15 SNVs during the outbreak; molecular clock calculations estimated 12.31 substitutions per genome per year (95% credibility interval, 7.81-17.05). Both intra- and interpatient diversification at the plasmid and transposon level was observed, significantly impacting the antibiogram of outbreak isolates. The majority of isolates evaluated (n = 27) harbored a blaCTX-M-15 gene, but some (n = 5) lacked the transposon carrying this gene, which resulted in susceptibility to aztreonam and third- and fourth-generation cephalosporins. Similarly, an isolate from a colonized patient lacked the transposon carrying rmtF and aac(6')lb genes, resulting in susceptibility to aminoglycosides. CONCLUSIONS: This study broadens the understanding of how bacteria diversify at the genomic level over the course of a defined outbreak and provides reference for future outbreak investigations.


Asunto(s)
Carbapenémicos/farmacología , Colangiopancreatografia Retrógrada Endoscópica/efectos adversos , Infecciones por Klebsiella/epidemiología , Infecciones por Klebsiella/transmisión , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/genética , beta-Lactamasas/genética , Infección Hospitalaria , Brotes de Enfermedades , Activación Enzimática , Variación Genética , Genoma Bacteriano , Humanos , Klebsiella pneumoniae/clasificación , Filogenia , Plásmidos/genética , Secuenciación Completa del Genoma , beta-Lactamasas/metabolismo
20.
J Clin Microbiol ; 55(6): 1827-1836, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-28356417

RESUMEN

Carbapenemase-producing Enterobacteriaceae (CPE) are a significant threat to public health. In 2015, CDC revised the surveillance definition for CPE to include all Enterobacteriaceae resistant to any carbapenem tested. However, this definition is associated with poor specificity. We evaluated the performance of this definition, compared to carbapenemase PCR, for a collection of 125 Enterobacteriaceae We also investigated the impact of ancillary testing for carbapenemase of isolates that met the CDC CPE surveillance definition. The two ancillary tests evaluated were the Xpert Carba-R assay, a molecular test, and the carbapenem inactivation method (CIM). Two variables were evaluated for the CIM: suspension of organisms in double-distilled water (ddH2O) versus tryptic soy broth (TSB) to incubate disks, and incubation of plates for 6 h versus 18 to 20 h. The sensitivity and specificity of the Carba-R assay were 100% compared to the results of in-house PCR. The sensitivities of the CIM performed with TSB were 94.6% when read at 6 h and 97.7% when read at 18 to 20 h; the sensitivities with ddH2O were 88.0% when read at 6 h and 93.0% when incubated for 18 to 20 h. The specificity was 100% for all variables tested. Without ancillary testing, the sensitivity of the CDC definition was 98.9% for CPE, and the specificity was 6.1%. Testing isolates that screened positive by the CDC definition with the Xpert Carba-R did not change the sensitivity, and it improved the specificity to 100%. Similarly, the use of the CIM (TSB and 18 to 20 h of incubation) to confirm screen-positive isolates resulted in a sensitivity of 95.6% and specificity of 100%.


Asunto(s)
Proteínas Bacterianas/análisis , Proteínas Bacterianas/genética , Técnicas Bacteriológicas/métodos , Enterobacteriaceae Resistentes a los Carbapenémicos/aislamiento & purificación , beta-Lactamasas/análisis , beta-Lactamasas/genética , Humanos , Sensibilidad y Especificidad
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