RESUMEN
We conducted an international multicentre evaluation to assess the clinical performance characteristics of the new multiplex PCR-based BD MAX Check-Points CPO assay to detect the 5 major carbapenemase families: KPC, VIM/IMP (tested simultaneously), NDM and OXA-48 compared to a reference method consisting of 2 culture methods (to improve recovery of CPO isolates from the rectal swabs), followed by carbapenem susceptibility testing and sequencing of target carbapenemase genes. Tests were performed from rectal swab specimens in ESwab collection and transport devices. Positive percent agreement (PPA) for BD MAX Check-Points CPO for KPC and OXA-48 were 88.2% (95% CI:72.6-96.7) and 96.2% (95% CI:80.4-99.9), respectively. Negative percent agreement was ≥99% for each gene. Insufficient samples (≤10) were positive for VIM/IMP or NDM tests to calculate meaningful PPA values. The BD MAX Check-Points CPO assay represents an accurate tool for rapid recognition of patients with rectal colonization by the most commonly encountered CPOs.
Asunto(s)
Proteínas Bacterianas/metabolismo , Farmacorresistencia Bacteriana Múltiple/genética , Bacterias Gramnegativas/enzimología , Bacterias Gramnegativas/genética , beta-Lactamasas/metabolismo , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Técnicas Bacteriológicas/métodos , Carbapenémicos/farmacología , Regulación Bacteriana de la Expresión Génica , Regulación Enzimológica de la Expresión Génica , Humanos , Reacción en Cadena de la Polimerasa Multiplex/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Recto/microbiología , Sensibilidad y Especificidad , beta-Lactamasas/genéticaRESUMEN
Delaying effective antibiotic therapy is a major cause of sepsis-associated mortality. The EUCAST rapid antibiotic susceptibility test (RAST) is performed from positive blood cultures to provide rapid results. Disc diffusion tests inoculated with positive blood culture broth are read at 4, 6, and 8 h and interpreted against species and time-specific criteria. Potential problems are the possibility of missing specific reading times for tests and slower growth in incubators that are frequently opened. The current study aimed to assess if digital visualization by the BD Kiestra™ total laboratory automation system is suitable for reading RASTs by capturing images at the correct times and retaining them for review. Utilizing the Kiestra™ InoqulA, 100 µl of positive blood culture broth was lawn-inoculated onto Mueller-Hinton agar and incubated at 35 °C for automated digital zone measurement at 4, 6, and 8 h. Aliquots from 135 positive blood cultures were tested against EUCAST-recommended and other drugs and assessed for readability of digital images. Microdilution MICs were determined in parallel to RASTs. All isolates except 7/10 enterococci yielded images of suitable quality for zone measurement. Of the 641 digitally read tests for other organisms, 207 (32.3%) were readable in 4 h, 555 (86.6%) in 6 h, and 641 (100%) in 8 h. For tests included in EUCAST criteria, 92.1% provided categorical agreement with microdilution MICs. Digital image reading of RASTs is a potentially viable, inexpensive tool for providing rapid susceptibility results which can help reduce sepsis-associated mortality.
Asunto(s)
Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Pruebas de Sensibilidad Microbiana/métodos , Automatización/métodos , Bacterias/crecimiento & desarrollo , Infecciones Bacterianas/microbiología , Cultivo de Sangre , Computadores , Humanos , Pruebas de Sensibilidad Microbiana/instrumentaciónRESUMEN
OBJECTIVE: The current BD Kiestra™ total laboratory automation (TLA) system automates specimen inoculation, incubation, and digital visualization of cultures prior to initiation of manual or semi-automated identification (ID) and antimicrobial susceptibility testing (AST). The current study aimed to compare the performance, in a clinical setting, of a fully automated research-use-only prototype, BD Kiestra™ IdentifA/SusceptA (automated system), to our current BD Kiestra™ TLA which utilizes manual or semi-automated IDs and ASTs (current system). METHODS: Clinical samples yielding significant growth after processing by the BD Kiestra™ TLA were tested in parallel for ID and AST by both systems. IDs and ASTs were determined by Bruker matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and BD Phoenix, respectively, with data stored and managed in the BD EpiCenter™. The automated system used a common inoculum preparation for both tests, whereas the current system used separate inocula. Results were compared to assess agreement between the systems. RESULTS: On initial testing, 89% of IDs (466/523) and 92.4% of IDs (484/523) for the automated and current ID systems, respectively, yielded acceptable MALDI-TOF log scores of ≥1.7. On repeat testing, the respective acceptable scores were 97.1% (508/523) and 98.1% (513/523). For initial ASTs, the automated and current systems yielded 97.5% categorical agreement for 7325 drug-organism tests. After omitting discrepant MICs that differed by only one dilution and categorical discrepancies that were not reproducible, 0.2% unresolved discrepancies remained thus (99.8% categorical agreement). CONCLUSIONS: The automated prototype is suitable for development into technology that will provide clinical microbiology laboratories with significant advantages such as improved efficiency, standardization, reproducibility, reduced technical error and greater safety.
RESUMEN
Carbapenemase-producing organisms (CPOs) are Gram-negative bacteria that are typically resistant to most or all antibiotics and are responsible for a global pandemic of high mortality. Rapid, accurate detection of CPOs and the classification of their carbapenemases are valuable tools for reducing the mortality of the CPO-associated infections, preventing the spread of CPOs, and optimizing use of new ß-lactamase inhibitor combinations such as ceftazidime/avibactam, meropenem/vaborbactam and imipenem/relebactam. The current study evaluated the performance of CPO Complete, a novel, manual, phenotypic carbapenemase detection and classification test. The test was evaluated for sensitivity and specificity against 262 CPO isolates of Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii and 67 non-CPO isolates. It was also evaluated for carbapenemase classification accuracy against 205 CPOs that produced a single carbapenemase class. The test exhibited 100% sensitivity 98.5% specificity for carbapenemase detection within 90 minutes and detected 74.1% of carbapenemases within 10 minutes. In the classification evaluation, 99.0% of carbapenemases were correctly classified for isolates that produced a single carbapenemase. The test is technically simple and has potential for adaptation to automated instruments. With lyophilized kit storage at temperatures up to 38°C, the CPO Complete test has the potential to provide rapid, accurate carbapenemase detection and classification in both limited resource and technologically advanced laboratories.
Asunto(s)
Acinetobacter baumannii/enzimología , Proteínas Bacterianas/clasificación , Proteínas Bacterianas/metabolismo , Enterobacteriaceae/enzimología , Pruebas de Sensibilidad Microbiana/métodos , Pseudomonas aeruginosa/enzimología , beta-Lactamasas/clasificación , beta-Lactamasas/metabolismo , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/aislamiento & purificación , Antibacterianos/farmacología , Enterobacteriaceae/efectos de los fármacos , Enterobacteriaceae/aislamiento & purificación , Pruebas de Enzimas , Humanos , Fenotipo , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/aislamiento & purificaciónRESUMEN
BACKGROUND: PCR tests now outnumber antigen tests for the diagnosis of respiratory syncytial virus (RSV) infection in the US. Recent analyses have shown that the traditional 10% positivity threshold to define an RSV season by rapid antigen testing was inappropriate for real-time PCR testing, for which 3% positivity appeared more appropriate. OBJECTIVE: To respectively model antigen (10%) and PCR (3%) positivity thresholds at national and regional levels using a large dataset of RSV testing results from US hospital-affiliated laboratories. STUDY DESIGN: From 2011-2016, 599 laboratories participated in a national RSV surveillance program (RSVAlert®). For laboratories with ≥10 tests for ≥30 weeks of a season, national and regional test numbers and positivity were summarized by test type overall, by season, and weekly within each season. Test type positivity thresholds were used to calculate season onset and offset. RESULTS: A seasonal average of 543,387 RSV tests was reported. PCR testing increased from 26% in 2011-2012 to 72% in 2015-2016. Overall, national positivity was 15.6% for antigen and 8.3% for PCR testing. National RSV season onsets and offsets were comparable using the 10% antigen and 3% PCR thresholds, but PCR-defined seasons generally started and ended later than antigen-defined seasons. Regionally, there were fewer outlier estimates of RSV season length when the predominant regional test type was used to define the season. CONCLUSION: RSV positivity rates differed by test type, likely due to differential clinical use of the tests. These findings support the use of distinct positivity thresholds by test type.
Asunto(s)
Antígenos Virales/análisis , Reacción en Cadena en Tiempo Real de la Polimerasa/estadística & datos numéricos , Infecciones por Virus Sincitial Respiratorio/diagnóstico , Virus Sincitial Respiratorio Humano/inmunología , Pruebas Diagnósticas de Rutina/estadística & datos numéricos , Pruebas Diagnósticas de Rutina/tendencias , Humanos , Lactante , Masculino , Modelos Teóricos , Vigilancia de la Población , Prevalencia , Infecciones por Virus Sincitial Respiratorio/inmunología , Virus Sincitial Respiratorio Humano/genética , Estados UnidosRESUMEN
This study compared the activity of cefepime + zidebactam (FEP-ZID) and selected currently available antibacterial agents against a panel of multidrug-resistant (MDR) clinical isolates chosen to provide an extreme challenge for antibacterial activity. FEPâ»ZID had a very broad and potent in vitro spectrum of activity, and was highly active against many MDR isolates of Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter baumannii. Notably, it inhibited isolates producing carbapenemases of Ambler classes A, B, and D, and P. aeruginosa isolates with multiple resistance mechanisms including combinations of upregulated efflux, diminished or non-functional OprD porins, and AmpC overproduction. Its clinical role will be determined initially by the breakpoints assigned to it, comparison studies with other investigational ß-lactamase inhibitor combinations, and ultimately by the developing body of therapeutic outcome data.
RESUMEN
Clinical laboratories test for extended-spectrum ß-lactamases (ESBLs) for epidemiological and infection control purposes and also for the potential of cephalosporins to cause therapeutic failures. Testing can be problematic, because the CLSI does not recommend the testing of all producers of ESBLs and also falsely negative results may occur with isolates that coproduce AmpC. Boronic acid-supplemented tests can enhance ESBL detection in AmpC producers. Because aztreonam inhibits AmpCs, a study was designed to compare ESBL detection by the CLSI disk test (CLSI), a boronic acid-supplemented CLSI disk test (CLSI plus BA), and an aztreonam plus clavulanate disk test (ATM plus CA). The study tested 100 well-characterized Enterobacteriaceae, Acinetobacter baumannii, and Pseudomonas aeruginosa isolates. Seventy produced TEM, SHV, or CTX-M ESBLs, with 15 coproducing an AmpC and 11 coproducing a metallo-ß-lactamase. Thirty ESBL-negative isolates were also tested. Tests were inoculated by CLSI methodology and interpreted as positive if an inhibitor caused a zone diameter increase of ≥5 mm. The percentages of ESBL producers detected were as follows: ATM plus CA, 95.7%; CLSI plus BA, 88.6%; and CLSI, 78.6%. When AmpC was coproduced, the sensitivities of the tests were as follows: ATM plus CA, 100%; CLSI plus BA, 93.3%; and CLSI, 60%. ATM plus CA also detected an ESBL in 90.1% of isolates that coproduced a metallo-ß-lactamase. Falsely positive tests occurred only with the CLSI and CLSI plus BA tests. Overall, the ATM plus CA test detected ESBLs more accurately than the CLSI and CLSI plus BA tests, especially with isolates coproducing an AmpC or metallo-ß-lactamase.
Asunto(s)
Aztreonam/farmacología , Bacterias/enzimología , Técnicas Bacteriológicas/métodos , Ácido Clavulánico/farmacología , beta-Lactamasas/análisis , Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Pruebas de Sensibilidad Microbiana/normas , Resistencia betalactámica/efectos de los fármacos , Inhibidores de beta-Lactamasas/farmacologíaRESUMEN
There is an urgent need for rapid, accurate detection and classification of carbapenemases. The current study evaluated the automated BD Phoenix CPO Detect and the manual bioMérieux Rapidec Carba NP tests for meeting these needs. Both tests were challenged with 294 isolates of Enterobacteriaceae spp., Pseudomonas aeruginosa, and Acinetobacter baumannii chosen to provide extreme diagnostic difficulty. Carbapenemases such as KPC, NMC-A, IMI, SME, NDM, SPM, IMP, VIM, and OXA-23, 40, 48, 58, 72, 181, and 232 were produced by 243 isolates and 51 carbapenemase-negative isolates included porin mutants and producers of extended-spectrum ß-lactamases (ESBLs), AmpCs, K1, and broad-spectrum ß-lactamases. Both tests exhibited high sensitivity of carbapenemase detection (>97%). Due to the highly challenging carbapenemase-negative isolates, specificities were lower than typical for evaluations involving mostly routine clinical isolates. BD Phoenix CPO Detect was 68.6% specific and Rapidec Carba NP was 60.8% to 78.4% specific, depending on how borderline results were interpreted. Only BD Phoenix CPO Detect classified carbapenemases. It correctly classified 85.0% of class A, 72.4% of class B, and 88.6% of class D carbapenemases. Importantly with respect to empirical therapy with new ß-lactamase inhibitor combinations such as ceftazidime/avibactam, no class B carbapenemases were misclassified as class A carbapenemases. Both tests offer advantages. Used alone, without initial susceptibility tests, Rapidec Carba NP can provide positive results for some isolates after only 10 to 30 min incubation. BD Phoenix CPO Detect provides novel advantages such as automated carbapenemase detection, inclusion in susceptibility panels to eliminate delays and subjectivity in initiating carbapenemase tests, and classification of most carbapenemases.
Asunto(s)
Proteínas Bacterianas/análisis , Proteínas Bacterianas/clasificación , Técnicas Bacteriológicas/métodos , Pruebas Diagnósticas de Rutina/métodos , beta-Lactamasas/análisis , beta-Lactamasas/clasificación , Acinetobacter baumannii/enzimología , Enterobacteriaceae/enzimología , Pseudomonas aeruginosa/enzimología , Sensibilidad y EspecificidadRESUMEN
BACKGROUND: The use of topical antimicrobial agents for management of minor skin infections is a clinical strategy that is commonly practiced in the community. Coupled with the use of topical antimicrobial agents is the emergence of antibiotic-resistant strains of pathogens leading to the need for alternative treatments. OBJECTIVE: A novel topical combination ointment consisting of salicylic acid, oak bark extract, benzoic acid, and polyethylene glycol (Bensal HP, Sonar products Inc., Carlstadt, NJ) with antimicrobial properties was assessed to determine its spectrum of activity. METHODS: One hundred eighty-four bacterial and fungal isolates from culture collections that included multidrug-resistant bacteria such as methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter spp, and gram-negative so-called superbugs, as well as yeasts and filamentous fungi, were investigated by cylinder diffusion and agar dilution assays. RESULTS: All 184 bacterial and fungal isolates were susceptible to the combination ointment at the clinically applied concentration and there was no evidence of cross-resistance between Bensal HP and other classes of antimicrobials. In time-kill tests, Bensal HP was rapidly bactericidal against P aeruginosa ATCC 27853 and methicillin-resistant S aureus SA179 at 4 × the MIC, a concentration that is applied clinically. CONCLUSIONS: The results of this study suggest that this combination ointment has a broad in vitro spectrum of antimicrobial activity against both more common bacterial and fungal pathogens and may be particularly useful for treatment of infections by multidrug-resistant organisms. Additional studies are warranted to investigate the full clinical utility as a therapeutic agent and also for possible infection control interventions.
RESUMEN
Enterobacter cloacae strain G6809 with reduced susceptibility to carbapenems was identified from a patient in a long-term acute care hospital in Kentucky. G6809 belonged to sequence type (ST) 88 and carried two carbapenemase genes, bla(KPC-18) and bla(VIM-1). Whole-genome sequencing localized bla(KPC-18) to the chromosome and bla(VIM-1) to a 58-kb plasmid. The strain was highly resistant to ceftazidime-avibactam. Insidious coproduction of metallo-ß-lactamase with KPC-type carbapenemase has implications for the use of next-generation ß-lactam-ß-lactamase inhibitor combinations.
Asunto(s)
Proteínas Bacterianas/biosíntesis , Enterobacter cloacae/enzimología , Infecciones por Enterobacteriaceae/microbiología , beta-Lactamasas/biosíntesis , Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Enterobacter cloacae/efectos de los fármacos , Enterobacter cloacae/genética , Orden Génico , Sitios Genéticos , Humanos , Pruebas de Sensibilidad Microbiana , Inhibidores de beta-Lactamasas/farmacología , beta-Lactamas/farmacologíaAsunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/genética , Imipenem/farmacología , Klebsiella pneumoniae/efectos de los fármacos , Tienamicinas/farmacología , beta-Lactamasas/genética , Humanos , Klebsiella pneumoniae/clasificación , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/aislamiento & purificación , Meropenem , Pruebas de Sensibilidad MicrobianaRESUMEN
The accurate detection of carbapenemase-producing organisms is a major challenge for clinical laboratories. The Carba NP test is highly accurate but inconvenient, as it requires frequent preparation of fresh imipenem solution. The current study was designed to compare the Carba NP test to two alternative tests for accuracy and convenience. These were a modified Carba NP test that utilized intravenous (i.v.) imipenem-cilastatin, which is less expensive than reference standard imipenem powder, and an updated version of the Rosco Neo-Rapid Carb kit, which does not require the preparation of imipenem solution and has a shelf life of 2 years. The comparison included 87 isolates that produced class A carbapenemases (including KPC-2, -3, -4, -5, -6, and -8, NMC-A, and SME type), 40 isolates that produced metallo-ß-lactamases (including NDM-1, GIM-1, SPM-1, IMP-1, -2, -7, -8, -18, and -27, and VIM-1, -2, and -7), 11 isolates that produced OXA-48, and one isolate that produced OXA-181. Negative controls consisted of 50 isolates that produced extended-spectrum ß-lactamases (ESBLs), AmpCs (including hyperproducers), K1, other limited-spectrum ß-lactamases, and porin and efflux mutants. Each test exhibited 100% specificity and high sensitivity (Carba NP, 100%; Rosco, 99% using modified interpretation guidelines; and modified Carba NP, 96%). A modified approach to interpretation of the Rosco test was necessary to achieve the sensitivity of 99%. If the accuracy of the modified interpretation is confirmed, the Rosco test is an accurate and more convenient alternative to the Carba NP test.