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1.
J Clin Microbiol ; : e0035924, 2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38904385

RESUMEN

Medical microbiologists, defined as doctoral-level laboratory directors with subspecialty training in medical microbiology, lead the clinical laboratory operations through activities such as clinical consultations, oversight of diagnostic testing menu, institutional leadership, education, and scholastic activities. However, unlike their clinical colleagues, medical microbiologists are largely unable to bill for clinical consultations performed within the hospital and, therefore, unable to generate relative value units or a similar quantifiable metric. As hospital budgets tighten and justification of staffing becomes a necessity, this may present a challenge to the medical microbiologist attempting to prove their value to the organization. To aid in providing tangible data, the Personnel Standards and Workforce subcommittee of the American Society for Microbiology conducted a multi-center study across seven medical centers to document clinical consultations and their impact. Consults were generated equally from internal (laboratory-based) and external (hospital-based) parties, with the majority directly impacting patient management. Near universal acceptance of the medical microbiologist's recommendation highlights the worth derived from their expertise. External consults required more time commitment from the medical microbiologist than internal consults, although both presented ample opportunity for secondary value, including impact through stewardship, education, clinical guidance, and cost reduction. This study is a description of the content and impact of consultations that underscore the importance of the medical microbiologist as a key member of the healthcare team. IMPORTANCE: Medical microbiologists are invaluable to the clinical microbiology laboratory and the healthcare system as a whole. However, as medical microbiologists do not regularly generate relative value units, capturing and quantifying the value provided is challenging. As hospital budgets tighten, justification of staffing becomes a necessity. To aid in providing tangible data, the Personnel Standards and Workforce subcommittee of the American Society for Microbiology conducted a multi-center study across seven medical centers to document clinical consultations and their impact. To our knowledge, this is the first study to provide detailed evaluation of the consultative value provided by medical microbiologists.

2.
J Clin Microbiol ; 61(4): e0171222, 2023 04 20.
Artículo en Inglés | MEDLINE | ID: mdl-36912659

RESUMEN

The Streptococcus bovis group (previously group D streptococci) consists of seven distinct species and subspecies. Definitive identification within the group is important, as certain organisms have been associated with gastrointestinal carcinoma, bacteremia, infective endocarditis, meningitis, biliary tract disease, and carcinoma, among others. Definitive identification, however, remains elusive due to limitations and inconsistencies across commonly used identification platforms in the United States. Here, we compared the performance of standard biochemical (Trek Gram-positive identification [GPID] plate, Vitek 2 GPID), sequencing (16S rDNA, sodA) databases (NCBI, RDP, CDC MicrobeNet), and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) platforms (Vitek MS, Bruker Biotyper MS) using a set of eight type strains representing all seven strains within the S. bovis group. Despite the evaluation of contemporary methods, no single platform was able to definitively identify all type strains within the S. bovis group. Vitek MS (85.7%, 7/8) provided the most accurate definitive identifications, followed by sodA sequencing (75%, 6/8). Vitek 2 and Bruker Biotyper RUO platforms performed the next best (62.5%, 5/8). All remaining platforms failed to adequately differentiate type strains within the S. bovis group (range, 0 to 37.5%). Laboratorians and clinicians should be aware of the identification limitations of routine testing algorithms and incorporate reflex testing, when appropriate, to platforms such as Vitek MS and/or sodA sequencing that are more able to definitively identify S. bovis group organisms. Further clinical evaluation was conducted using 65 clinical isolates from three geographically distinct U.S. institutions. Future improvements in identification platforms may reveal new clinical and epidemiological trends for members of the S. bovis group.


Asunto(s)
Bacteriemia , Endocarditis , Streptococcus bovis , Humanos , Streptococcus bovis/genética , Proteómica , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos
3.
J Antimicrob Chemother ; 78(4): 1034-1040, 2023 04 03.
Artículo en Inglés | MEDLINE | ID: mdl-36869724

RESUMEN

OBJECTIVES: We evaluated the clinical characteristics and outcomes of patients with COVID-19 who received three-drug combination regimens for treatment of carbapenem-resistant Acinetobacter baumannii (CRAB) infections during a single-centre outbreak. Our objective was to describe the clinical outcomes and molecular characteristics and in vitro synergy of antibiotics against CRAB isolates. MATERIALS AND METHODS: Patients with severe COVID-19 admitted between April and July 2020 with CRAB infections were retrospectively evaluated. Clinical success was defined as resolution of signs/symptoms of infection without need for additional antibiotics. Representative isolates underwent whole-genome sequencing (WGS) and in vitro synergy of two- or three-drug combinations was assessed by checkerboard and time-kill assays, respectively. RESULTS: Eighteen patients with CRAB pneumonia or bacteraemia were included. Treatment regimens included high-dose ampicillin-sulbactam, meropenem, plus polymyxin B (SUL/MEM/PMB; 72%), SUL/PMB plus minocycline (MIN; 17%) or other combinations (12%). Clinical resolution was achieved in 50% of patients and 30-day mortality was 22% (4/18). Seven patients had recurrent infections, during which further antimicrobial resistance to SUL or PMB was not evident. PMB/SUL was the most active two-drug combination by checkerboard. Paired isolates collected before and after treatment with SUL/MEM/PMB did not demonstrate new gene mutations or differences in the activity of two- or three-drug combinations. CONCLUSIONS: Use of three-drug regimens for severe CRAB infections among COVID-19 resulted in high rates of clinical response and low mortality relative to previous studies. The emergence of further antibiotic resistance was not detected phenotypically or through WGS analysis. Additional studies are needed to elucidate preferred antibiotic combinations linked to the molecular characteristics of infecting strains.


Asunto(s)
Infecciones por Acinetobacter , Acinetobacter baumannii , COVID-19 , Humanos , Carbapenémicos/farmacología , Carbapenémicos/uso terapéutico , Estudios Retrospectivos , Infecciones por Acinetobacter/tratamiento farmacológico , Sinergismo Farmacológico , Antibacterianos/uso terapéutico , Combinación de Medicamentos , Acinetobacter baumannii/genética , Pruebas de Sensibilidad Microbiana
4.
Emerg Infect Dis ; 27(12): 3195-3197, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34808094

RESUMEN

We report a case of septic shock attributable to monomicrobial bloodstream infection secondary to Wohlfahrtiimonas chitiniclastica infection. This case suggests that W. chitiniclastica likely possesses the virulence to cause severe disease. Culture-independent techniques were essential in the identification of this organism, which enabled selection of appropriate therapy.


Asunto(s)
Bacteriemia , Gammaproteobacteria , Infecciones por Bacterias Gramnegativas , Xanthomonadaceae , Bacteriemia/diagnóstico , Bacteriemia/tratamiento farmacológico , Infecciones por Bacterias Gramnegativas/diagnóstico , Infecciones por Bacterias Gramnegativas/tratamiento farmacológico , Humanos , Masculino
5.
J Clin Microbiol ; 59(7): e0178420, 2021 06 18.
Artículo en Inglés | MEDLINE | ID: mdl-33504591

RESUMEN

Fungal infections are a rising threat to our immunocompromised patient population, as well as other nonimmunocompromised patients with various medical conditions. However, little progress has been made in the past decade to improve fungal diagnostics. To jointly address this diagnostic challenge, the Fungal Diagnostics Laboratory Consortium (FDLC) was recently created. The FDLC consists of 26 laboratories from the United States and Canada that routinely provide fungal diagnostic services for patient care. A survey of fungal diagnostic capacity among the 26 members of the FDLC was recently completed, identifying the following diagnostic gaps: lack of molecular detection of mucormycosis; lack of an optimal diagnostic algorithm incorporating fungal biomarkers and molecular tools for early and accurate diagnosis of Pneumocystis pneumonia, aspergillosis, candidemia, and endemic mycoses; lack of a standardized molecular approach to identify fungal pathogens directly in formalin-fixed paraffin-embedded tissues; lack of robust databases to enhance mold identification with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; suboptimal diagnostic approaches for mold blood cultures, tissue culture processing for Mucorales, and fungal respiratory cultures for cystic fibrosis patients; inadequate capacity for fungal point-of-care testing to detect and identify new, emerging or underrecognized, rare, or uncommon fungal pathogens; and performance of antifungal susceptibility testing. In this commentary, the FDLC delineates the most pressing unmet diagnostic needs and provides expert opinion on how to fulfill them. Most importantly, the FDLC provides a robust laboratory network to tackle these diagnostic gaps and ultimately to improve and enhance the clinical laboratory's capability to rapidly and accurately diagnose fungal infections.


Asunto(s)
Laboratorios , Mucorales , Canadá , Técnicas de Laboratorio Clínico , Testimonio de Experto , Humanos
6.
Malar J ; 17(1): 23, 2018 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-29321025

RESUMEN

BACKGROUND: Autosplenectomy, as a result of sickle cell disease, is an important risk factor for severe malaria. While molecular methods are helpful in providing rapid and accurate infection detection and species identification, the effect of hyposplenism on result interpretation during the course of infection should be carefully considered. CASE PRESENTATION: A 32-year old autosplenectomized Nigerian male with severe sickle cell disease was referred to the National Institutes of Health for allogenic hematopoietic stem cell transplant. Despite testing negative for malaria by both smear and PCR 2 weeks after arrival in the USA, the patient developed fever and diffuse bilateral lower rib cage and upper abdominal pain 2 weeks later and subsequently tested positive for Plasmodium falciparum. Parasitaemia was tracked over time by microscopy and nucleic acid tests to evaluate the therapeutic response in the setting of hyposplenism. The patient showed prompt resolution of patent infection by microscopy but remained positive by molecular methods for > 30 days after treatment initiation. CONCLUSION: While molecular testing can provide sensitive Plasmodium nucleic acid detection, the persistence of Plasmodium nucleic acids following adequate treatment in functionally asplenic patients can lead to a diagnostic dilemma. In such patients, clinical response and peripheral blood smears should guide patient management following treatment. Nonetheless, in pre-transplant patients at high-risk for pre-existing Plasmodium infections, highly sensitive molecular assays can be useful to rule out infection prior to transplantation.


Asunto(s)
Anemia de Células Falciformes/complicaciones , Antimaláricos/uso terapéutico , ADN Protozoario/sangre , Monitoreo de Drogas/métodos , Malaria Falciparum/diagnóstico , Malaria Falciparum/patología , Adulto , Humanos , Malaria Falciparum/tratamiento farmacológico , Masculino , Microscopía , Ácidos Nucleicos , Reacción en Cadena de la Polimerasa , Factores de Tiempo , Estados Unidos
7.
J Bacteriol ; 197(9): 1592-605, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25691530

RESUMEN

UNLABELLED: Campylobacter jejuni is a leading cause of bacterial diarrheal disease and a frequent commensal of the intestinal tract in poultry and other animals. For optimal growth and colonization of hosts, C. jejuni employs two-component regulatory systems (TCSs) to monitor environmental conditions and promote proper expression of specific genes. We analyzed the potential of C. jejuni Cjj81176_1484 (Cjj1484) and Cjj81176_1483 (Cjj1483) to encode proteins of a cognate TCS that influences expression of genes possibly important for C. jejuni growth and colonization. Transcriptome analysis revealed that the regulons of the Cjj81176_1484 (Cjj1484) histidine kinase and the Cjj81176_1483 (Cjj1483) response regulator contain many common genes, suggesting that these proteins likely form a cognate TCS. We found that this TCS generally functions to repress expression of specific proteins with roles in metabolism, iron/heme acquisition, and respiration. Furthermore, the TCS repressed expression of Cjj81176_0438 and Cjj81176_0439, which had previously been found to encode a gluconate dehydrogenase complex required for commensal colonization of the chick intestinal tract. However, the TCS and other specific genes whose expression is repressed by the TCS were not required for colonization of chicks. We observed that the Cjj1483 response regulator binds target promoters in both unphosphorylated and phosphorylated forms and influences expression of some specific genes independently of the Cjj1484 histidine kinase. This work further expands the signaling mechanisms of C. jejuni and provides additional insights regarding the complex and multifactorial regulation of many genes involved in basic metabolism, respiration, and nutrient acquisition that the bacterium requires for optimal growth in different environments. IMPORTANCE: Bacterial two-component regulatory systems (TCSs) link environmental cues to expression of specific genes that enable optimal bacterial growth or colonization of hosts. We found that the Campylobacter jejuni Cjj1484 histidine kinase and Cjj1483 response regulator function as a cognate TCS to largely repress expression of target genes encoding a gluconate dehydrogenase complex required for commensal colonization of the chick intestinal tract, as well as other genes encoding proteins for heme or iron acquisition, metabolism, and respiration. We also discovered different modes by which Cjj1483 may mediate repression with and without Cjj1484. This work provides insight into the signal transduction mechanisms of a leading cause of bacterial diarrheal disease and emphasizes the multifactorial and complex regulation of specific biological processes in C. jejuni.


Asunto(s)
Campylobacter jejuni/enzimología , Campylobacter jejuni/crecimiento & desarrollo , Regulación Bacteriana de la Expresión Génica , Proteínas Quinasas/metabolismo , Regulón , Factores de Transcripción/metabolismo , Perfilación de la Expresión Génica , Histidina Quinasa , Transducción de Señal
9.
10.
J Bacteriol ; 195(21): 4936-46, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23995631

RESUMEN

Intramembrane metalloproteases (IMMPs) control critical biological processes by cleaving membrane-associated proteins within a transmembrane segment or at a site near the membrane surface. Phylogenetic analysis divides IMMPs into four groups. SpoIVFB is a group III IMMP that regulates Bacillus subtilis endospore formation by cleaving Pro-σ(K) and releasing the active sigma factor from a membrane. To elucidate the enzyme-substrate interaction, single-cysteine versions of catalytically inactive SpoIVFB and C-terminally truncated Pro-σ(K)(1-126) (which can be cleaved by active SpoIVFB) were coexpressed in Escherichia coli, and proximity was tested by disulfide cross-linking in vivo. As expected, the results provided evidence that catalytic residue Glu-44 of SpoIVFB is near the cleavage site in the substrate. Also near the cleavage site were two residues of SpoIVFB in predicted conserved loops; Pro-135 in a short loop and Val-70 in a longer loop. Pro-135 corresponds to Pro-399 of RseP, a group I IMMP, and Pro-399 was reported previously to interact with substrate near the cleavage site, suggesting a conserved interaction across IMMP subfamilies. Val-70 follows a newly recognized conserved motif, PXGG (X is a large hydrophobic residue), which is in a hydrophobic region predicted to be a membrane reentrant loop. Following the hydrophobic region is a negatively charged region that is conserved in IMMPs of groups I and III. At least two residues with a negatively charged side chain are required in this region for activity of SpoIVFB. The region exhibits other features in IMMPs of groups II and IV. Its possible roles, as well as that of the short loop, are discussed. New insights into IMMP-substrate interaction build toward understanding how IMMPs function and may facilitate manipulation of their activity.


Asunto(s)
Bacillus subtilis/metabolismo , Proteínas Bacterianas/metabolismo , Membrana Celular/metabolismo , Endopeptidasas/metabolismo , Regulación Bacteriana de la Expresión Génica/fisiología , Proteínas de la Membrana/metabolismo , Factor sigma/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Dominio Catalítico , Cisteína/química , Endopeptidasas/química , Endopeptidasas/genética , Regulación Enzimológica de la Expresión Génica/fisiología , Proteínas de la Membrana/química , Proteínas de la Membrana/genética , Modelos Moleculares , Filogenia , Unión Proteica , Conformación Proteica , Factor sigma/química , Factor sigma/genética
11.
Clin Lab Med ; 43(2): 209-220, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37169443

RESUMEN

Invasive fungal infections are increasing worldwide due to factors such as climate change and immunomodulating therapies. Unfortunately, the detection of these infections is limited due to the low sensitivity and long periods required for laboratory testing. Point-of-care testing could lead to more rapid diagnosis of these often devasting infections. However, there are currently no true point-of-care tests on the market for the detection of fungi. In this article, the current state of fungal antigen and molecular testing is reviewed, with commentary on the potential for development and use in the point-of-care setting.


Asunto(s)
Micosis , Humanos , Micosis/diagnóstico , Pruebas en el Punto de Atención , Antígenos Fúngicos , Sistemas de Atención de Punto , Técnicas de Diagnóstico Molecular , Sensibilidad y Especificidad , Mananos
12.
J Appl Lab Med ; 7(6): 1283-1289, 2022 10 29.
Artículo en Inglés | MEDLINE | ID: mdl-36214370

RESUMEN

BACKGROUND: The VITEK® 2 is generally accepted as a reliable method for predicting antibiotic resistance mechanisms including aminoglycoside phenotypes, beta lactam phenotypes, impermeability, and penicillinases. However, when it comes to predicting carbapenemases, the research that has been done is inconsistent in both methods and results. METHODS: We compared the predictions of the VITEK 2 and Advanced Expert System™ (AES) with the results of the modified carbapenemase inactivation method in an academic medical center lab to evaluate the clinical reliability of the VITEK 2 and AES in routine workflow for the detection of carbapenemases. RESULTS: Our findings show that the positive predictive value of carbapenemase detection on the VITEK2 and AES is 30.3% (91/300) in our patient population. CONCLUSIONS: In light of these results, we propose that the VITEK 2 and AES be used as a screening tool for carbapenemase-containing organisms rather than as a definitive test.


Asunto(s)
Computadores , beta-Lactamasas , Humanos , Reproducibilidad de los Resultados , Pruebas de Sensibilidad Microbiana , beta-Lactamasas/genética
13.
JAC Antimicrob Resist ; 4(3): dlac067, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35774069

RESUMEN

Invasive fungal diseases cause significant morbidity and mortality, in particular affecting immunocompromised patients. Resistant organisms are of increasing importance, yet there are many notable differences in the ability to both perform and interpret antifungal susceptibility testing compared with bacteria. In this review, we will highlight the strengths and limitations of resistance data of pathogenic yeasts and moulds that may be used to guide treatment and predict clinical outcomes.

14.
J Bacteriol ; 193(7): 1681-9, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21257775

RESUMEN

Upon starvation, a dense population of rod-shaped Myxococcus xanthus bacteria coordinate their movements to construct mounds in which some of the cells differentiate to spherical spores. During this process of fruiting body formation, short-range C-signaling between cells regulates their movements and the expression of genes important for sporulation. C-signaling activates FruA, a transcription factor that binds cooperatively with another transcription factor, MrpC2, upstream of the fmgA and fmgBC promoters, activating transcription. We have found that a third C-signal-dependent gene, herein named fmgD, is subject to combinatorial control by FruA and MrpC2. The two proteins appear to bind cooperatively upstream of the fmgD promoter and activate transcription. FruA binds proximal to the fmgD promoter, as in the fmgBC promoter region, whereas MrpC2 binds proximal to the fmgA promoter. A novel feature of the fmgD promoter region is the presence of a second MrpC2 binding site partially overlapping the promoter and therefore likely to mediate repression. The downstream MrpC2 site appears to overlap the FruA site, so the two transcription factors may compete for binding, which in both cases appears to be cooperative with MrpC2 at the upstream site. We propose that binding of MrpC2 to the downstream site represses fmgD transcription until C-signaling causes the concentration of active FruA to increase sufficiently to outcompete the downstream MrpC2 for cooperative binding with the upstream MrpC2. This would explain why fmgD transcription begins later during development and is more dependent on C-signaling than transcription of fmgA and fmgBC.


Asunto(s)
Proteínas Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica/fisiología , Myxococcus xanthus/genética , Myxococcus xanthus/metabolismo , Proteínas Bacterianas/genética , Sitios de Unión , ADN Bacteriano , Regiones Promotoras Genéticas , Unión Proteica , Factores de Tiempo
15.
J Appl Lab Med ; 6(6): 1635-1639, 2021 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-34156472

RESUMEN

BACKGROUND: The COVID-19 pandemic has strained clinical microbiology laboratories due to testing supply allocations. As a result, laboratories have had to invest in multiple COVID-19 assays performed on different testing instruments. Comparing the results achieved by testing positive samples between in-use assays can provide insights into which platforms may be interchangeable for testing in times of supply chain emergencies. METHODS: Nasopharyngeal and nasal swab specimens collected in viral transport media that tested positive on the Xpert® Xpress SARS-CoV-2 assay were tested on the ePlex® SARS-CoV-2 and BD SARS-CoV-2 Reagents for BD Max™ assays. Positive percent agreement was calculated using the Xpert Xpress SARS-CoV-2 assay as the reference method. RESULTS: We tested 78 positive swabs, resulting in a positive percentage agreement (PPA) of 92% (CI 84-97%) for the BD SARS-CoV-2 assay and 58% (CI 47-70%) for the ePlex assay. Following development of a new workflow for the ePlex, we detected SARS-CoV-2 in 7 additional samples, resulting in a new PPA of 68% (CI 56-78). CONCLUSIONS: During times of supply allocation and shortage of the Xpert Xpress SARS-CoV-2 assay, the BD SARS-CoV-2 assay is well suited to test substitutions due to its high PPA.


Asunto(s)
COVID-19 , Pandemias , Humanos , ARN Viral/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , SARS-CoV-2 , Sensibilidad y Especificidad
16.
J Appl Lab Med ; 6(6): 1484-1491, 2021 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-34191020

RESUMEN

BACKGROUND: An evolving COVID-19 testing landscape and issues with test supply allocation, especially in the current pandemic, has made it challenging for ordering providers. We audited orders of the Xpert® Xpress SARS-CoV-2 PCR with reverse transcription (RT-PCR) platform-the fastest of several other testing modalities available-to illuminate these challenges utilizing a multidisciplinary laboratory professional team consisting of a pathology resident and microbiology laboratory director. METHODS: Retrospective review of the first 5 hundred Xpert Xpress SARS-CoV-2 RT-PCR test orders from a 2-week period to determine test appropriateness based on the following indications: emergency surgery, emergent obstetric procedures, initial behavioral health admission, and later including discharge to skilled care facilities and pediatric admissions. Our hypothesis was that a significant proportion of orders for this testing platform were inappropriate. RESULTS: On review, a significant proportion of orders were incorrect, with 69.8% (n = 349, P < 0.0001) not meeting indications for rapid testing. Of all orders, 249 designated as emergency surgery were inappropriate, with 49.0% of those orders never proceeding with any surgical intervention; most of these were trauma related (64.6% were orders associated with a trauma unit). CONCLUSIONS: Significant, pervasive inappropriate ordering practices were identified at this center. A laboratory professional team can be key to identifying problems in testing and play a significant role in combating inappropriate test utilization.


Asunto(s)
COVID-19 , Centros Médicos Académicos , Prueba de COVID-19 , Niño , Femenino , Humanos , Embarazo , Estudios Retrospectivos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , SARS-CoV-2
17.
Open Forum Infect Dis ; 8(6): ofab240, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34262985

RESUMEN

BACKGROUND: Streptococcus pyogenes, or Group A Streptococcus (GAS), is not considered a typical cause of infective endocarditis (IE), but has anecdotally been observed in unexpectedly high rates in people who inject drugs (PWID) at our institution. METHODS: All cases of possible or definite GAS IE per Modified Duke Criteria in adults at an academic hospital between 11/15/2015 and 11/15/2020 were identified. Medical records were reviewed for demographics, comorbidities, treatment, and outcomes related to GAS IE. The literature on cases of GAS IE was reviewed. RESULTS: Eighteen cases of probable (11) or definite (7) GAS IE were identified; the mean age was 38 years, and the population was predominantly female (56%) and Caucasian (67%), which is inconsistent with local population demographics. Sixteen cases were in people who inject drugs (PWID; 89%); 14 were also homeless, 6 also had HIV (33%), and 2 were also pregnant. Antibiotic regimens were variable due to polymicrobial bacteremia (39%). One patient underwent surgical valve replacement. Four patients (22%) died due to complications of infection. The literature review revealed 42 adult cases of GAS IE, only 17 of which were in PWID (24%). CONCLUSIONS: The 16 cases of possible and definite GAS IE in PWID over a 5-year period in a single institution reported nearly doubles the number of cases in PWID from all previous reports. This suggests a potential increase in GAS IE particularly in PWID and PWH, which warrants further epidemiologic investigation.

18.
Diagn Microbiol Infect Dis ; 99(3): 115261, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33290922

RESUMEN

BACKGROUND: Staphylococcus lugdunensis is a coagulase negative Staphylococcus species and frequent human skin commensal with the potential for aggressive infection. Guidance surrounding S. lugdunensis bacteremia (SLB) from a single set of blood cultures is lacking. METHODS: A multicenter, retrospective cohort of patients with SLB from at least one blood culture set within the University of Maryland Medical System from 2015 to 2019 is presented. Objectives are to describe baseline characteristics, compare the clinical status and treatment course, and to evaluate the clinical outcomes among patients with SLB in single versus multiple sets. RESULTS: Thirty-six patients were included, 24 with one set of blood cultures positive for S lugdunensis and 12 with multiple sets. Baseline characteristics were similar between the groups, though patients with SLB in multiple sets were more commonly on hemodialysis (P = 0.029). Central lines were the most common source (17%). Most (97%) fulfilled systemic inflammatory response syndrome or Souvenir criteria, had an infectious focus on imaging, or had a second positive culture site. Most (78%) were treated as clinically significant. Patients with multiple positive sets were more commonly treated with antibiotics for >2 weeks (P = 0.02). CONCLUSIONS: SLB was rare and occurred more frequently as a single set of positive cultures. Patient characteristics and clinical courses were similar between single and multiple set groups. Given the potential severity of S. lugdunensis bacteremia it seems prudent to treat S. lugdunensis in a single blood culture as true bacteremia, pending larger studies and guidelines.


Asunto(s)
Bacteriemia/microbiología , Infecciones Estafilocócicas/sangre , Staphylococcus lugdunensis/aislamiento & purificación , Adulto , Anciano , Anciano de 80 o más Años , Cultivo de Sangre/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos
19.
J Appl Lab Med ; 3(4): 675-685, 2019 01.
Artículo en Inglés | MEDLINE | ID: mdl-31639735

RESUMEN

BACKGROUND: Sepsis is a life-threatening condition with high rates of morbidity and mortality; effective and appropriate antibiotic therapy is essential for ensuring patient improvement. To aid in the diagnosis of sepsis, blood cultures are drawn and sent to the microbiology laboratory for pathogen growth, identification, and susceptibility testing. The clinical microbiology laboratory can assist the medical team by providing timely identification of the pathogen(s) causing the bloodstream infection through the use of rapid diagnostic technology. One of these rapid diagnostic technologies, MALDI-TOF MS, has been proven to reduce the time required for appropriate antibiotic therapy when used to identify pathogens grown in culture. This technology has also been used to identify pathogens directly from the positive blood cultures with great success. CONTENT: In this minireview, we summarize the different methods that have been developed to directly identify pathogens from positive blood cultures by use of MALDI-TOF MS and the effect of this technology on patient outcomes. Additionally, we touch on current research in the field, including the identification of antimicrobial resistance directly from positive blood cultures by MALDI-TOF MS. SUMMARY: Rapid identification of pathogens is important in the survival of patients undergoing a septic event. MALDI-TOF MS technology has played an important role in rapid identification, which has led to a reduction in the time to appropriate antibiotic therapy and contributed to the improvement of patient outcomes. The high sensitivity and specificity of MALDI-TOF MS identification, in combination with MALDI-TOF's rapid function and reduced labor costs, make this technology an attractive choice for clinical laboratories.


Asunto(s)
Bacteriemia/diagnóstico , Bacterias/aislamiento & purificación , Cultivo de Sangre , Fungemia/diagnóstico , Hongos/aislamiento & purificación , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Antiinfecciosos/farmacología , Antiinfecciosos/uso terapéutico , Bacteriemia/tratamiento farmacológico , Bacteriemia/microbiología , Farmacorresistencia Microbiana , Fungemia/tratamiento farmacológico , Fungemia/microbiología , Humanos , Pruebas de Sensibilidad Microbiana/métodos , Sensibilidad y Especificidad , Factores de Tiempo , Tiempo de Tratamiento
20.
Diagn Microbiol Infect Dis ; 91(2): 130-135, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29454652

RESUMEN

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has revolutionized fungal identification. Previously, we developed a MALDI-TOF MS mold extraction procedure and comprehensive database. While MALDI-TOF MS has become routine in a few laboratories, it has not yet become widespread. A major obstacle is the lack of a simple, reproducible and uniform protein extraction procedure. In this study, we developed and validated a rapid one-step protein extraction protocol for filamentous fungi. Excised molds were placed into tubes containing zirconia-silica beads and extraction solution without washing or ethanol inactivation steps. Extraction solutions containing different ratios of acetonitrile and formic acid were evaluated. Samples were then processed using a PowerLyzer high power bead based homogenizer and supernatants spotted for MALDI-TOF MS. The rapid method was evaluated prospectively and in parallel to our current mold extraction protocol for 3 months. Analysis of 106 clinical mold isolates resulted in an improved performance and a decrease in extraction time by 30 minutes to a total of 5 minutes of hands-on time. Acceptable identification scores (≥ 2.00) were achieved for up to 63.0% of mold isolates by the rapid method compared with 52.8% of isolates by the current routine protocol. Score comparisons between duplicate spots showed higher reproducibility of the rapid method as compared to the routine method. The rapid extraction method allows efficient analysis of clinical mold isolates both in scheduled batch runs and on an in-demand basis while providing a simple starting platform for laboratories adopting MALDI-TOF MS for mold identification.


Asunto(s)
Hongos , Técnicas de Tipificación Micológica/métodos , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Hongos/química , Hongos/clasificación , Hongos/aislamiento & purificación , Humanos , Micosis/microbiología , Estudios Prospectivos , Reproducibilidad de los Resultados
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