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1.
Artigo em Inglês | MEDLINE | ID: mdl-33649112

RESUMO

Hydrogen peroxide (H2O2) and hypochlorous acid (HOCl) are biocides used for cleaning and debriding chronic wound infections, which often harbor drug resistant bacteria. Here, we evaluated the in vitro activity of H2O2 and HOCl against 27 isolates of eight bacterial species involved in wound infections. Minimum inhibitory concentrations (MICs) and minimum biofilm bactericidal concentrations (MBBCs) were measured. When compared to their respective MICs, MBBCs of isolates exposed to H2O2 were 16- to 1,024-fold higher and those exposed to HOCl were 2- to 4-fold higher. We evaluated selection of resistance after exposure of Staphylococcus aureus and Pseudomonas aeruginosa biofilms to 10 iterations of electrochemically generated HOCl or H2O2 delivered using electrochemical scaffolds (e-scaffolds), observing no decrease in anti-biofilm effects with serial exposure to e-scaffold-generated H2O2 or HOCl. 24-hour exposure to H2O2-generating e-scaffolds consistently decreased colony forming units (CFUs) of S. aureus and P. aeruginosa biofilms by ∼5.0-log10 and ∼4.78-log10 through 10 iterations of exposure, respectively. 4-hour exposure to HOCl-generating e-scaffolds consistently decreased CFUs of S. aureus biofilms by ∼4.9-log10, and 1-hour exposure to HOCl-generating e-scaffolds consistently decreased CFUs of P. aeruginosa biofilms by ∼1.57-log10 These results suggest that HOCl has similar activity against planktonic and biofilm bacteria, whereas the activity of H2O2 is less against biofilm than planktonic bacteria, and that repeat exposure to either biocide, generated electrochemically under the experimental conditions studied, does not lessen antibiofilm effects.

2.
Artigo em Inglês | MEDLINE | ID: mdl-33609642

RESUMO

BACKGROUND: Periprosthetic joint infection (PJI) is a relatively frequent and oftentimes devastating complication after total elbow arthroplasty (TEA). Its microbiologic diagnosis is usually based on periprosthetic tissue culture (hereafter referred to as tissue culture), but the sensitivity of tissue culture is variable. Although implant sonication cultures have been shown to be superior to tissue cultures for the diagnosis of hip and knee PJI, only a single small study (of fewer than 10 infected implants) has assessed sonication for PJI diagnosis after elbow arthroplasty. METHODS: We retrospectively analyzed 112 sonicate fluid cultures from patients who underwent revision of a TEA at a single institution between 2007 and 2019, comparing results to those of tissue cultures. We excluded patients who had fewer than 2 tissues submitted for culture. Using the IDSA guidelines to define PJI, there were 49 infected cases and 63 aseptic failures. Median ages in the PJI and aseptic failure groups were 66 and 61 years, respectively. In the aseptic failure group, 65% were female versus 63% in the PJI group. We reviewed clinical characteristics and calculated the sensitivity and specificity of tissue compared to sonicate fluid culture. In addition, we compared the sensitivity of tissue culture to the combination of tissue and sonicate fluid culture. RESULTS: The most common pathogens were coagulase negative Staphylococcus species (49%), followed by Staphylococcus aureus (12%). Sensitivity of tissue culture was 63% and sensitivity of sonicate fluid culture was 76% (p=0.109). Specificity of tissue culture was 94% and specificity of sonicate fluid culture was 100%. Sensitivity of sonicate fluid culture in combination with tissue culture was 84% (p=0.002 compared to tissue culture alone). CONCLUSION: In this study, we found that the combination of sonicate fluid and tissue culture had a greater sensitivity than tissue culture alone for microbiologic diagnosis of PJI after TEA. LEVEL OF EVIDENCE: Level III; Diagnostic Study.

3.
J Clin Microbiol ; 2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33627320

RESUMO

Reported cases of tick-borne diseases have steadily increased for more than a decade. In the United States, a majority of tick-borne infections are caused by bacteria. Clinical diagnosis may be challenging as tick-borne diseases can present with similar symptoms. Laboratory diagnosis has historically relied on serologic methods, which have limited utility during the acute phase of disease. Pathogen-specific molecular methods have improved early diagnosis, but can be expensive when bundled together and miss unexpected or novel pathogens. To address these shortcomings, we developed a 16S ribosomal RNA (rRNA) gene PCR with next-generation sequencing approach to detect tick-borne bacteria in whole blood. A workflow was optimized by comparing combinations of two extractions platforms and two primer sets, ultimately pursuing DNA extraction from blood with the MagNA Pure 96 and PCR amplification using dual-priming oligonucleotide primers specific to the V1-V3 region of the 16S rRNA gene. The amplified product underwent modified Illumina 16S metagenomics sequencing library preparation and sequencing on a MiSeq V2 Nano flow cell, with data analysis using Pathogenomix RipSeq NGS software. Results with the developed method were compared to those from a V1-V2 16S rRNA gene primer set described by the Centers for Disease Control and Prevention (CDC). The V1-V3 assay demonstrated equivalent performance to the CDC assay, with each method showing concordance with targeted PCR results in 31 of 32 samples, and detecting 22 of 23 expected organisms. These data demonstrate the potential for using a broad-range bacterial detection approach for diagnosis of tick-borne bacterial infection from blood.

4.
J Clin Microbiol ; 2021 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33536295

RESUMO

Helicobacter pylori infection is mainly diagnosed non-invasively, with susceptibility testing traditionally requiring endoscopy. Treatment is empiric, with clarithromycin triple therapy recommended where resistance rates are below 15%. Rising clarithromycin resistance resulting in high therapy failure rates is seen worldwide but United States data is limited. We developed a real-time PCR assay for simultaneous detection of H. pylori and genotypic markers of clarithromycin resistance directly from stool specimens. The assay was validated by testing 524 stool samples using an H. pylori stool antigen test as the reference method for detection accuracy and Sanger sequencing to confirm genotypic susceptibility results. A separate set of 223 antigen positive stool samples was tested and retrospective medical record review conducted to define clinical utility. PCR resulted in 88.6% and 92.8% sensitivity in the validation and clinical study sets, respectively. Sequencing confirmed correct detection of clarithromycin resistance-associated mutations in all positive validation samples. The PCR predicted clarithromycin resistance rate was 39% in the clinical data set overall and 28% in treatment naïve patients; the clarithromycin triple therapy eradication rate in treatment naïve patients was 62%. The clarithromycin triple therapy success was lower when resistance was predicted by PCR (41%) than when no resistance was predicted (70%, p=0.03). PCR was positive in 98% of antigen positive stools from patients tested for eradication. The described PCR assay can accurately and non-invasively diagnose H. pylori, provide genotypic susceptibility, and test for eradication. Our findings support the need for susceptibility-guided therapy in our region if a clarithromycin-based regimen is considered.

5.
Clin Infect Dis ; 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33588438

RESUMO

In December 2019, the Antibacterial Resistance Leadership Group (ARLG) was awarded funding for another seven-year cycle to support a clinical research network on antibacterial resistance. ARLG 2.0 has three overarching research priorities: (1) infections caused by antibiotic resistant (AR) Gram-negative bacteria; (2) infections caused by AR Gram-positive bacteria, and (3) diagnostic tests to optimize use of antibiotics. To support the next generation of AR researchers, the ARLG offers three mentoring opportunities: the ARLG Fellowship, Early Stage Investigator Seed Grants, and the Trialists in Training Program. The purpose of this article is to update the scientific community on the progress made in the original funding period and to encourage submission of clinical research that addresses one or more of the research priority areas of ARLG 2.0.

6.
Artigo em Inglês | MEDLINE | ID: mdl-33406034

RESUMO

The taxonomic position of Yersinia kristensenii subsp. rochesterensis and Yersinia occitanica was re-evaluated by genomic analysis. Average nucleotide identity (ANI), digital DNA-DNA hybridization values, and phylogenetic analyses of the type strains indicate that Y. kristensenii subsp. rochesterensis and Y. occitanica are the same genospecies. Additionally, the overall genomic relatedness index (OGRI) values reveal that Y. kristensenii subsp. rochesterensis should be elevated to species status as Yersinia rochesterensis sp. nov.

7.
Artigo em Inglês | MEDLINE | ID: mdl-33397650

RESUMO

Oxidizing agents like hypochlorous acid (HOCl) have antimicrobial activity. We developed an integrated electrochemical scaffold, or e-scaffold, that delivers a continuous low dose of HOCl aimed at targeting microbial biofilms without exceeding concentrations toxic to humans as a prototype of a device being developed to treat wound infections in humans. In this work, we tested the device against 33 isolates of bacteria (including isolates with acquired antibiotic resistance) grown as in vitro biofilms alongside 12 combinations of dual-species in vitro biofilms. Biofilms were grown on the bottoms of 12-well plates for 24 h. An integrated e-scaffold was placed atop each biofilm and polarized at 1.5 V for 1, 2, or 4 h. HOCl was produced electrochemically by oxidizing chloride ions (Cl-) in solution to chlorine (Cl2); dissolved Cl2 spontaneously dissociates in water to produce HOCl. The cumulative concentration of HOCl produced at the working electrode in each well was estimated to be 7.89, 13.46, and 29.50 mM after 1, 2, and 4 h of polarization, respectively. Four hours of polarization caused an average reduction of 6.13 log10 CFU/cm2 (±1.99 log10 CFU/cm2) of viable cell counts of monospecies biofilms and 5.53 log10 CFU/cm2 (±2.31 log10 CFU/cm2) for the 12 dual-species biofilms studied. The described integrated e-scaffold reduces viable bacterial cell counts in biofilms formed by an array of antibiotic-susceptible and -resistant bacteria alone and in combination.

8.
Clin Infect Dis ; 2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33480973

RESUMO

BACKGROUND: Accurate molecular diagnostic tests are necessary for confirming a diagnosis of coronavirus disease 2019 (COVID-19). Direct detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acids in respiratory tract specimens informs patient, healthcare institution and public health level decision-making. The numbers of available SARS-CoV-2 nucleic acid detection tests are rapidly increasing, as is the COVID-19 diagnostic literature. Thus, the Infectious Diseases Society of America (IDSA) recognized a significant need for frequently updated systematic reviews of the literature to inform evidence-based best practice guidance. OBJECTIVE: The IDSA's goal was to develop an evidence-based diagnostic guideline to assist clinicians, clinical laboratorians, patients and policymakers in decisions related to the optimal use of SARS-CoV-2 nucleic acid amplification tests. In addition, we provide a conceptual framework for understanding molecular diagnostic test performance, discuss the nuance of test result interpretation in a variety of practice settings and highlight important unmet research needs in the COVID-19 diagnostic testing space. METHODS: IDSA convened a multidisciplinary panel of infectious diseases clinicians, clinical microbiologists, and experts in systematic literature review to identify and prioritize clinical questions and outcomes related to the use of SARS-CoV-2 molecular diagnostics. Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was used to assess the certainty of evidence and make testing recommendations. RESULTS: The panel agreed on 17 diagnostic recommendations. CONCLUSIONS: Universal access to accurate SARS-CoV-2 nucleic acid testing is critical for patient care, hospital infection prevention and the public response to the COVID-19 pandemic. Information on the clinical performance of available tests is rapidly emerging, but the quality of evidence of the current literature is considered moderate to very low. Recognizing these limitations, the IDSA panel weighed available diagnostic evidence and recommends nucleic acid testing for all symptomatic individuals suspected of having COVID-19. In addition, testing is recommended for asymptomatic individuals with known or suspected contact with a COVID-19 case. Testing asymptomatic individuals without known exposure is suggested when the results will impact isolation/quarantine/personal protective equipment (PPE) usage decisions, dictate eligibility for surgery, or inform solid organ or hematopoietic stem cell transplantation timing. Ultimately, prioritization of testing will depend on institutional-specific resources and the needs of different patient populations.

9.
J Microbiol Methods ; 181: 106131, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33385441

RESUMO

Ureaplasma species, including Ureaplasma parvum and Ureaplasma urealyticum, are challenging to culture and maintain. Here, we describe a novel bioreactor for growing high-titer liquid Ureaplasma cultures in a stable manner.

10.
Nat Rev Microbiol ; 19(1): 23-36, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32814862

RESUMO

Antibiotic-resistant bacterial infections arising from acquired resistance and/or through biofilm formation necessitate the development of innovative 'outside of the box' therapeutics. Nanomaterial-based therapies are promising tools to combat bacterial infections that are difficult to treat, featuring the capacity to evade existing mechanisms associated with acquired drug resistance. In addition, the unique size and physical properties of nanomaterials give them the capability to target biofilms, overcoming recalcitrant infections. In this Review, we highlight the general mechanisms by which nanomaterials can be used to target bacterial infections associated with acquired antibiotic resistance and biofilms. We emphasize design elements and properties of nanomaterials that can be engineered to enhance potency. Lastly, we present recent progress and remaining challenges for widespread clinical implementation of nanomaterials as antimicrobial therapeutics.

11.
Clin Infect Dis ; 2020 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-33277647

RESUMO

Respiratory tract infections (RTIs) drive many outpatient encounters and despite being predominantly viral, are associated with high rates of antibiotic prescriptions. With rising antibacterial resistance, optimization of prescribing of antibiotics in outpatients with RTIs is a critical need. Fortunately, this challenge arises at a time of increasing availability of novel RTI diagnostics to help discern which patients have bacterial infections warranting treatment. Effective implementation of antibiotic stewardship is needed, but optimal approaches for ambulatory settings are unknown. Future research needs are reviewed in this summary of a research summit convened by the Infectious Diseases Society of America in the fall of 2019.

12.
Shoulder Elbow ; 12(6): 390-398, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33281943

RESUMO

Introduction: Cutibacterium acnes is a recognized culprit for implant-associated infections, but positive cultures do not always indicate clinically relevant infection. Studies have shown a correlation between the ß-hemolytic phenotype of C. acnes and its infectious capacity, but correlation with genetic phylotype has not been performed in literature. The purpose of this study is to evaluate ß-hemolysis phenotype, genetic phylotype, and mid-term clinical outcomes of C. acnes isolated from orthopedic surgical sites. Methods: Fifty-four C. acnes isolates previously obtained from surgical wounds of patients undergoing hip, knee, shoulder, or spine implant removal were re-cultured. There were 21 females and 33 males with an average age of 59 years (range, 18-84). Twenty-four were from clinically infected sites whereas 30 were considered contaminants. De novo ß-hemolysis was analyzed and a retrospective chart review was performed to evaluate clinical outcomes at 7.1 years (range, 0.1-12.8). Results: On Brucella agar with 5% rabbit blood, 46% of contaminant and 43% of infectious isolates were hemolytic. Type II phylotype was significantly more nonhemolytic regardless of infectious or contaminant status (p < 0.05). Type 1B correlated with a hemolytic-infectious phenotype and Type 1A with a hemolytic-contaminant phenotype but was not statistically significant. Conclusion: The ß-hemolytic profile of C. acnes did not correlate with phylotype or clinically relevant orthopedic infection.

13.
Clin Infect Dis ; 2020 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-33300545

RESUMO

BACKGROUND: Cutibacterium species are common pathogens in periprosthetic joint infections (PJI). These infections are often treated with ß-lactams or clindamycin as monotherapy, or in combination with rifampin. Clinical evidence supporting the value of adding rifampin for treatment of Cutibacterium PJI is lacking. MATERIALS/METHODS: In this multicenter retrospective study, we evaluated patients with Cutibacterium PJI. The primary endpoint was clinical success, defined by the absence of infection relapse or new infection within a minimal follow-up of 12 months. We used Fisher's exact tests and Cox proportional hazards models to analyze the effect of rifampin and other factors on clinical success after PJI. RESULTS: We included 187 patients (72.2% male, median age 67 years) with a median follow-up of 36 months. The surgical intervention was two-stage exchange in 95 (50.8%), one-stage exchange in 51 (27.3%), debridement and implant retention (DAIR) in 34 (18.2%), and explantation without reimplantation in 7 (3.7%). Rifampin was included in the antibiotic regimen in 81 (43.3%) cases. Infection relapse occurred in 28 (15.0%), and new infection in 13 (7.0%) cases. In the time-to-event analysis, DAIR (adjusted HR=2.15, p=0.03) and antibiotic treatment over 6 weeks (adjusted HR=0.29, p=0.0002) significantly influenced treatment failure. We observed a tentative evidence for a beneficial effect of adding rifampin to the antibiotic treatment - though not statistically significant for treatment failure (adjusted HR=0.5, p=0.07) and not for relapses (adjusted HR=0.5, p=0.10). CONCLUSIONS: We conclude that a rifampin combination is not markedly superior in Cutibacterium PJI but a dedicated prospective multicenter study is needed.

14.
J Clin Microbiol ; 2020 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-33328178

RESUMO

Bronchoalveolar lavage (BAL) culture is a standard, though time consuming, approach for identifying microorganisms in severe lower respiratory tract infections. Sensitivity of BAL culture is relatively low and prior antimicrobial therapy decreases the sensitivity further, leading to overuse of empiric antibiotics. The Unyvero LRT BAL Application (Curetis GmbH, Germany) is a multiplex molecular panel that detects 19 bacteria, 10 antibiotic resistance markers and a fungus, Pneumocystis jirovecii, in BAL fluid in ∼4.5 hours. Performance was evaluated using 1,016 prospectively collected and 392 archived specimens from 11 clinical trial sites in the United States. Overall positive and negative percent agreement with culture for identification of bacteria that grow in routine cultures were 93.4% and 98.3%, respectively, with additional potential pathogens identified by Unyvero in 21.7% of prospectively collected specimens. For detection of P. jirovecii, positive percent agreement with standard testing was 87.5%. Antibiotic resistance marker results were compared to standard antibiotic susceptibility testing to determine positive predictive values (PPVs). PPVs ranged from 80-100%, based on the microorganism and specific resistance marker(s). The Unyvero LRT BAL Application provides accurate detection of common agents of bacterial pneumonia and of P. jirovecii The sensitivity and rapidity of this panel suggests significant clinical value for choosing appropriate antibiotics and for antibiotic stewardship.

15.
Clin Infect Dis ; 2020 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-33354704

RESUMO

Enteroviral meningitis is seasonal, typically exhibiting a rise in prevalence in late summer/early fall. Based on clinical microbiology laboratory testing data of cerebrospinal fluid, the expected August/September/October peak in enteroviral meningitis did not occur in 2020, possibly related to COVID-19 mitigation strategies.

17.
Artigo em Inglês | MEDLINE | ID: mdl-33199387

RESUMO

Staphylococcus epidermidis is a major cause of periprosthetic joint infection (PJI); its intracellular persistence within osteoblasts may compromise therapy if that therapy is not intracellularly active. The intracellular activity of rifampin, rifapentine, and rifabutin was assessed against five rifampin-susceptible and two rifampin-resistant S. epidermidis isolates. Compared to no treatment, treatment resulted in a ≥2-fold log10 reduction of intracellular rifampin-susceptible, but not rifampin-resistant S. epidermidis These findings show activity of rifampin, rifapentine, and rifabutin against intra-osteoblast PJI-associated S. epidermidis.

18.
J Bone Joint Surg Am ; 2020 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-33165130

RESUMO

BACKGROUND: The synovial fluid test for alpha defensin has been reported to have an excellent performance in diagnosing periprosthetic joint infection (PJI). The purpose of this study was to evaluate the performance of the lateral flow test for synovial fluid alpha defensin by using the methods of a formal diagnostic accuracy study and to compare its performance with that of the laboratory-based alpha defensin test for PJI. METHODS: We conducted a diagnostic accuracy study of the index lateral flow immunoassay for synovial fluid alpha defensin relative to the reference 2013 Musculoskeletal Infection Society (MSIS) multicriteria definition of PJI. The study included a prospective multicenter cohort of outpatients with a failed hip or knee arthroplasty and a supplemental control cohort of fresh synovial fluid specimens submitted by physicians for diagnostic PJI testing. RESULTS: Among 57 patients with PJI and 248 patients without PJI in the overall prospective patient cohort, the sensitivity and specificity of the alpha defensin lateral flow test were 89.5% (95% confidence interval [CI]: 78.5% to 96.0%) and 94.8% (95% CI: 91.2% to 97.2%), respectively. The sensitivity increased to 94.3% (95% CI: 84.3% to 98.8%) after exclusion of 17 patients with grossly bloody aspirates (>1 million red blood cells/µL). Among the supplemental control cohort of fresh synovial fluid samples, including 65 samples from patients with PJI and 397 from patients without PJI, the sensitivity and specificity of the alpha defensin lateral flow test were 98.5% (95% CI: 91.7% to 100.0%) and 98.2% (95% CI: 96.4% to 99.3%), respectively. A comparison of the sensitivity and specificity of the alpha defensin lateral flow test with those of the alpha defensin enzyme-linked immunosorbent assay (ELISA) in the combined cohort did not demonstrate a significant difference in sensitivity (94.3% [95% CI: 88.5% to 97.7%] compared with 93.0% [95% CI: 87.1% to 96.7%]) or specificity (96.9% [95% CI: 95.3% to 98.1%] compared with 97.8% [95% CI: 96.4% to 98.8%]) (both p > 0.05). CONCLUSIONS: The results of this study demonstrate the solid diagnostic performance of the alpha defensin test and have resulted in the U.S. Food and Drug Administration (FDA) authorization of the lateral-flow test with an intended use as an aid in the clinical diagnosis of PJI. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

19.
Clin Infect Dis ; 2020 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-33104186

RESUMO

In this article, the editors of Clinical Infectious Diseases review some of the most important lessons they have learned about the epidemiology, clinical features, diagnosis, treatment and prevention of SARS-CoV-2 infection and identify essential questions about COVID-19 that remain to be answered.

20.
Artigo em Inglês | MEDLINE | ID: mdl-32962921

RESUMO

BACKGROUND: Arbekacin is a broad-spectrum aminoglycoside with activity against some Gram-positive and Gram-negative bacteria. METHODS: Arbekacin minimum inhibitory concentration (MIC) values were determined for 296 drug-resistant Gram-negative bacilli, and compared to previously determined plazomicin, amikacin, gentamicin, and tobramycin MIC values. RESULTS: The MIC values required to inhibit 50% and 90% of isolates (MIC50 and MIC90, respectively) were 16 and >128 µg/ml, respectively. CONCLUSIONS: Arbekacin showed similar MIC50 values to amikacin and gentamicin, a lower MIC50 value than tobramycin, and a higher MIC50 value than plazomicin.

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