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L Barth Reller

Publications and source records attributed to L Barth Reller.

At least 19 recordsLinked to original sources
PubMed2007

Comparative evaluation of Etest and sensititre yeastone panels against the Clinical and Laboratory Standards Institute M27-A2 reference broth microdilution method for testing Candida susceptibility to seven antifungal agents.

To assess their utility for antifungal susceptibility testing in our clinical laboratory, the Etest and Sensititre methods were compared with the Clinical and Laboratory Standards Institute (CLSI) M27-A2 reference broth microdilution method. Fluconazole (FL), itraconazole (I), voriconazole (V), posaconazole (P), flucytosine (FC), caspofungin (C), and amphotericin B (A) were tested with 212 Candida isolates. Reference MICs were determined after 48 h of incubation, and Etest and Sensititre MICs were determined after 24 h and 48 h of incubation. Overall, excellent essential agreement (EA) between the reference and test methods was observed for Etest (95%) and Sensititre (91%). Etest showed an >or=92% EA for MICs for all drugs tested; Sensititre showed a >or=92% EA for MICs for I, FC, A, and C but 82% for FL and 85% for V. The overall categorical agreement (CA) was 90% for Etest and 88% for Sensititre; minor errors accounted for the majority of all categorical errors for both systems. Categorical agreement was lowest for Candida glabrata and Candida tropicalis with both test systems. Etest and Sensititre provided better CA at 24 h compared to 48 h for C. glabrata; however, CA for C. glabrata was <80% for FL with both test systems despite MIC determination at 24 h. Agreement between technologists for both methods was >or=98% for each agent against all organisms tested. Overall, Etest and Sensititre methods compared favorably with the CLSI reference method for determining the susceptibility of Candida. However, further evaluation of their performance for determining the MICs of azoles, particularly for C. glabrata, is warranted.

Antifungal Agents↗
PubMed2007

Validation of laboratory screening criteria for herpes simplex virus testing of cerebrospinal fluid.

Most patients with herpes simplex virus (HSV) central nervous system (CNS) infection have abnormal cerebrospinal fluid (CSF) indices. Therefore, we implemented screening criteria based on CSF values and host immune status to guide testing. All CSF samples submitted for HSV PCR analysis from January 1999 through December 2004 were included in the study. Specimens from patients with human immunodeficiency virus, a history of transplants, an age of <2 years, a CSF white blood cell count of >5 cells/mm(3), or a protein level of >50 mg/dl were tested upon request. All other samples were rejected and frozen. To validate our screening criteria, rejected specimens were pooled and tested retrospectively. Electronic medical records were also reviewed. A total of 1,659 HSV PCR requests from 1,458 patients were screened. Of the 1,296 specimens (78.1%) accepted for testing, 1,213 were negative, 7 were positive for HSV type 1 (HSV-1), 26 were positive for HSV-2, and 50 had unavailable results. Sixteen requests were rejected because an alternative microbiologic diagnosis had been established. Of the 347 samples rejected based on criteria, 222 (64.0%) remained available for pooled testing. No HSV-1-positive samples were identified in the rejected specimens. Two rejected specimens tested positive for HSV-2 DNA, but both met acceptance criteria which had not been communicated to the laboratory. Few patients (7.8%) with rejected specimens were treated with acyclovir, which suggests a low clinical concern for HSV encephalitis. Acceptance criteria based on CSF parameters and host immune status saved time and cost and did not miss patients with HSV CNS infection. Communication between the clinician and the laboratory is imperative for a successful screening program.

Adult↗
PubMed2006

Use of vancomycin or first-generation cephalosporins for the treatment of hemodialysis-dependent patients with methicillin-susceptible Staphylococcus aureus bacteremia.

BACKGROUND: Because of its ease of dosing, vancomycin is commonly used to treat methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia in patients undergoing long-term hemodialysis. Clinical outcomes resulting from such a therapeutic strategy have not been well defined. METHODS: We prospectively identified patients undergoing long-term hemodialysis who received a diagnosis of MSSA bacteremia. Clinical outcomes were grouped according to the predominant antibiotic received during their therapy (vancomycin or a first-generation cephalosporin [cefazolin]). Treatment failure (defined as death or recurrent infection) was determined at 12 weeks after the initial positive blood culture results. A multivariable analysis was used to adjust for confounders. RESULTS: During an 84-month period, 123 hemodialysis-dependent patients with MSSA bacteremia were identified. Patients receiving vancomycin (n=77) tended to be younger (51 vs. 57 years; P=.06) and had a lower rates of metastatic complications at presentation (11.7% vs. 36.7%; P=.001) than did those receiving cefazolin (n=46). The 2 groups were similar with regard to Acute Physiology and Chronic Health Evaluation II scores, comorbidities, source of infection, type of hemodialysis access, and access removal rates. Treatment failure was more common among patients receiving vancomycin (31.2% vs. 13%; P=.02). In the multivariable analysis, factors independently associated with treatment failure included vancomycin use (odds ratio, 3.53; 95% confidence interval, 1.15-13.45) and retention of the hemodialysis access (odds ratio, 4.99; 95% confidence interval, 1.89-13.76). CONCLUSIONS: Hemodialysis-dependent patients with MSSA bacteremia treated with vancomycin are at a higher risk of experiencing treatment failure than are those receiving cefazolin. In the absence of patient specific circumstances (e.g., allergy to beta-lactams), vancomycin should not be continued beyond empirical therapy for hemodialysis-dependent patients with MSSA bacteremia.

Adult↗
PubMed2006

Controlled clinical comparison of VersaTREK and BacT/ALERT blood culture systems.

To assess the relative yields in automated microbial detection systems of bacteria and yeasts isolated from the blood of adult patients with suspected sepsis, we compared the new VersaTREK system (VTI) (TREK Diagnostic Systems, Cleveland, OH) to the BacT/ALERT 3D system (3D) (bioMérieux, Inc., Durham, NC). Identical protocols were followed for the two systems. Paired aerobic (REDOX 1) and anaerobic (REDOX 2) VTI media were compared with standard aerobic (SA) and anaerobic (SN) 3D media; each of the four culture bottles was filled with 6 to 9 ml of blood. All bottles flagged positive by the instruments were subcultured to determine both true-positive (growth) and false-positive (no growth) cultures. Additionally, to assess false-negative bottles, terminal subcultures were done on all negative companion bottles to true-positive bottles. All isolates were identified by standard methods. All 4 bottles were adequately filled and yielded 413 clinically significant isolates in 5,389 (79%) of the 6,786 4-bottle sets obtained. Although no overall difference in yield or in time to detection was detected between the two systems, significantly more streptococci and enterococci as a group were detected by VTI. Moreover, significantly more microorganisms were detected by VTI for patients receiving antimicrobial therapy. The two systems were comparable (P, not significant) at detecting the 179 unimicrobial episodes of bacteremia seen. False-positive rates for aerobic and anaerobic bottles, respectively, were 1.6% and 0.9% for VTI and 0.7% and 0.8% for 3D. We conclude that the VTI and 3D systems are comparable for detection of bloodstream infections with bacteria or yeasts.

Adult↗
PubMed2006

Multicenter studies of tigecycline disk diffusion susceptibility results for Acinetobacter spp.

Acinetobacter sp. isolates having multidrug resistance (MDR) patterns have become common in many medical centers worldwide, limiting therapeutic options. A five-center study tested 103 contemporary clinical Acinetobacter spp., including MDR strains, by reference broth microdilution and disk diffusion (15-mug disk content) methods against tigecycline. Applying U.S. Food and Drug Administration tigecycline breakpoint criteria for Enterobacteriaceae (susceptibility at < or =2 microg/ml [< or =1 microg/ml by the European Committee on Antimicrobial Susceptibility Testing]; disk diffusion breakpoints at > or =19 mm and < or =14 mm) to Acinetobacter spp. led to an unacceptable error rate (23.3%). However, an adjustment of tigecycline disk diffusion breakpoints (susceptible/resistant) to > or =16/ < or =12 mm reduced intermethod errors to an acceptable level (only 9.7%, all minor).

Acinetobacter↗
PubMed2006

Blood culture contamination in Tanzania, Malawi, and the United States: a microbiological tale of three cities.

We conducted retrospective, comparative analyses of contamination rates for cultures of blood obtained in the emergency rooms of Muhimbili National Hospital (MNH) in Dar es Salaam, Tanzania; Lilongwe Central Hospital (LCH) in central Malawi; and the Duke University Medical Center (DUMC) in the United States. None of the emergency room patients had indwelling intravascular devices at the time that the blood samples for cultures were obtained. In addition, we reviewed the contamination rates for a cohort of patients already hospitalized in the DUMC inpatient medical service, most of whom had indwelling intravascular devices. The bloodstream infection rates among the patients at MNH (n=513) and LCH (n=486) were similar (approximately 28%); the contamination rates at the two hospitals were 1.3% (7/513) and 0.8% (4/486), respectively. Of 54 microorganisms isolated from cultures of blood collected in the DUMC emergency room, 26 (48%) were identified as skin contaminants. Cultures of blood collected in the DUMC emergency room were significantly more likely to yield growth of contaminants than the cultures of blood collected in the emergency rooms at MNH and LCH combined (26/332 versus 11/1,003; P<0.0001) or collected in the DUMC inpatient medical service (26/332 versus 7/283; P<0.01). For the MNH and LCH blood cultures, lower contamination rates were observed when skin was disinfected with isopropyl alcohol plus tincture of iodine rather than isopropyl alcohol plus povidone-iodine. In conclusion, blood culture contamination was minimized in sub-Saharan African hospitals with substantially limited resources through scrupulous attention to aseptic skin cleansing and improved venipuncture techniques. Application of these principles when blood samples for culture are obtained in U.S. hospital emergency rooms should help mitigate blood culture contamination rates and the unnecessary microbiology workup of skin contaminants.

2-Propanol↗
PubMed2006

Emergence of Salmonella enterica serotype Paratyphi A as a major cause of enteric fever in Kathmandu, Nepal.

We performed pulsed-field gel electrophoresis (XbaI) on 114 bloodstream isolates of Salmonella enterica serotype Paratyphi A and S. enterica serotype Typhi collected from febrile patients in Kathmandu, Nepal. Of the 56 S. Paratyphi A isolates, 51 (91%) were indistinguishable, which suggests the emergence of a single clone. In contrast, only 21 (36%) of the 58 S. Typhi isolates exhibited a common genotype, which is consistent with endemic disease from multiple sources.

Adolescent↗
PubMed2006

Pyrogenic reactions in hemodialysis patients, Hanoi, Vietnam.

Of 33,111 patients admitted to a large hospital in Vietnam from November 2000 through July 2001, a total of 303 were undergoing hemodialysis and had pyrogenic reactions (ie, fever and/or rigors). Ten case patients (3.3%) had documented bacteremia; pathogens were largely waterborne microorganisms. Pyrogenic reactions in case patients might have occurred because of suboptimal water quality or inadequate dialyzer reprocessing procedures.

Adolescent↗
PubMed2006

Cost savings with implementation of PNA FISH testing for identification of Candida albicans in blood cultures.

Antifungal expenditures are substantial for many hospitals. Using caspofungin for the treatment of candidemia accounts for a sizable proportion of the costs. A cost minimization study that used a decision analytic model was done to compare in-hospital diagnosis and treatment costs using the Candida albicans peptide nucleic acid fluorescence in situ hybridization (PNA FISH) test versus the C. albicans screen test for differentiating C. albicans from non-albicans Candida species bloodstream infections. Assuming physician notification of yeast identity concurrent with blood culture positivity, potential savings resulting from use of the C. albicans PNA FISH test compared with the C. albicans screen test averaged $1837 per patient treated, although laboratory costs for doing the C. albicans PNA FISH test ($82.72) exceeded those for the C. albicans screen test ($2.83). Savings were realized through a decrease in antifungal drug costs, particularly caspofungin. Incorporating the C. albicans PNA FISH test as part of the initial identification algorithm for yeasts recovered from blood can result in substantial savings for hospitals.

Antifungal Agents↗
PubMed2006

Predictors of mortality in patients with bloodstream infection due to ceftazidime-resistant Klebsiella pneumoniae.

Bloodstream infection (BSI) due to multidrug-resistant Klebsiella is associated with high rates of morbidity and mortality. The aim of this study was to identify predictors of in-hospital mortality among patients with BSI due to ceftazidime-resistant (CAZ-R) Klebsiella pneumoniae at a tertiary care medical center. Patients with CAZ-R K. pneumoniae BSI were identified by our microbiology laboratory between January 1995 and June 2003. Clinical data were collected retrospectively. Logistic regression was used to identify independent predictors of all causes of in-hospital mortality. Of 779 patients with K. pneumoniae BSI, 60 (7.7%) had BSI due to CAZ-R K. pneumoniae; 43 (72%) of these were nosocomial infections. Pulsed-field gel electrophoresis identified a single predominant strain in 17 (28%) patients. The in-hospital mortality rate was 43% (n = 26). Among patients with CAZ-R K. pneumoniae BSI, those who died were similar to survivors with respect to demographic, clinical, and antimicrobial susceptibility characteristics. Only 43 (72%) patients received effective therapy within 5 days of BSI. In bivariable analysis, delay in initiation of effective therapy for >72 h after diagnosis of BSI was associated with death (P = 0.03). Strain genotype was not predictive of outcome. In multivariable analysis, delay in initiation of effective therapy for >72 h after diagnosis of BSI was an independent predictor of death (odds ratio, 3.32; 95% confidence interval, 1.07 to 10.3). Thus, among patients with BSI due to CAZ-R K. pneumoniae, a delay in the initiation of effective therapy of greater than 72 h after BSI was associated with a >3-fold increase in mortality risk.

Adolescent↗
PubMed2006

Utility of extended blood culture incubation for isolation of Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, and Kingella organisms: a retrospective multicenter evaluation.

The incidence of and average time to detection for Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, and Kingella (HACEK) bacteria in blood cultures with standard incubation and the utility of extended incubation of blood culture bottles were reviewed at four tertiary care microbiology laboratories. HACEK organisms were isolated from 35 (<0.005%) of 59,203 positive blood cultures. None of 407 blood cultures with extended incubation grew HACEK or other bacteria. Bacteremia from HACEK bacteria is rare, and extended incubation of blood cultures to recover HACEK bacteria is unnecessary.

Actinobacillus↗
PubMed2005

Prevalence of clinical isolates of Cryptococcus gattii serotype C among patients with AIDS in Sub-Saharan Africa.

Cryptococcus gattii is a group of exogenous, neurotropic yeasts that possess the capsular serotype B or C. Isolates of serotype C are extremely rare and, until recently, were known to infect only immunocompetent individuals. We genotyped 176 isolates of Cryptococcus from patients in sub-Saharan Africa who had AIDS; 22 (13.7%) of 161 isolates from Botswana and 2 (13.3%) of 15 isolates from Malawi were C. gattii serotype C strains. All of these serotype C strains belong to the rare VGIV genotype, possess the MAT alpha mating-type allele, and exhibit little genetic diversity.

Acquired Immunodeficiency Syndrome↗
PubMed2005

Repeat infective endocarditis: differentiating relapse from reinfection.

Repeat infective endocarditis due to the same species can represent relapse of the initial infection or a new infection. We used time-based clinical criteria and pulsed-field gel electrophoresis-based molecular criteria to classify 13 cases of repeat infective endocarditis as either relapse or reinfection. The agreement between clinical and molecular criteria was imperfect (agreement in 10 [77%] of 13 cases).

Endocarditis, Bacterial↗
PubMed2005

Risk factors for hematogenous complications of intravascular catheter-associated Staphylococcus aureus bacteremia.

BACKGROUND: The role of both host and pathogen characteristics in hematogenous seeding following Staphylococcus aureus bacteremia is incompletely understood. METHODS: Consecutive patients with intravascular catheter-associated Staphylococcus aureus bacteremia were prospectively recruited over a 91-month period. The corresponding bloodstream isolates were examined for the presence of 35 putative virulence determinants. Patient and bacterial characteristics associated with the development of hematogenous complications (HCs) (i.e., septic arthritis, vertebral osteomyelitis, or endocarditis) were defined. RESULTS: HC occurred in 42 (13%) of 324 patients. Patient characteristics at diagnosis that were associated with HC included community onset (relative risk [RR], 2.25; 95% confidence interval [CI], 1.24-4.07; P=.007), increased symptom duration (odds ratio for each day, 1.14; 95% CI, 1.06-1.2; P<.001), presence of a long-term intravascular catheter or noncatheter prosthesis (RR, 4.02; 95% CI, 1.74-9.27; P<.001), hemodialysis dependence (RR, 3.84; 95% CI, 2.08-7.10; P<.001), and higher APACHE II score (P=.02). Bacterial characteristics included sea (RR, 2.03; 95% CI, 1.16-3.55; P=.011) and methicillin-resistant S. aureus (MRSA) (RR, 2.09; 95% CI, 1.19-3.67; P=.015). Subsequent failure to remove a catheter was also associated with HC (RR, 2.28; 95% CI, 1.22-4.27; P=.011). On multivariable analysis, symptom duration, hemodialysis dependence, presence of a long-term intravascular catheter or a noncatheter device, and infection with MRSA remained significantly associated with HC. CONCLUSIONS: This investigation identifies 4 host- and pathogen-related risk factors for hematogenous bacterial seeding and reaffirms the importance of prompt catheter removal.

Adult↗
PubMed2005

Risk of endocarditis among patients with prosthetic valves and Staphylococcus aureus bacteremia.

PURPOSE: Staphylococcus aureus is a common cause of bacteremia and of native valve infective endocarditis. However, the risk of endocarditis in patients with a prosthetic valve who develop S. aureus bacteremia is unclear. The aim of this study was to define the risk of prosthetic valve endocarditis in patients with S. aureus bacteremia. SUBJECTS AND METHODS: All patients with a prosthetic valve or ring who developed S. aureus bacteremia during the 94-month study period were prospectively evaluated. The modified Duke criteria were used for the diagnosis of endocarditis. Patients were followed up for 12 weeks after the initial diagnosis of S. aureus bacteremia. RESULTS: The overall rate of definite prosthetic valve endocarditis among the study patients was 26/51 (51%). The risk of endocarditis was similar in patients with late (>or=12 months after valve implantation) vs. early S. aureus bacteremia (<12 months after prosthetic valve implantation) (50% vs. 52%, P=1.0), mitral vs. aortic prostheses (62% vs. 48%, P=0.24), and mechanical vs. bioprosthetic valves (62% vs. 44%, P=0.29). The 12-week mortality was higher among patients with definite vs. possible endocarditis (62% vs. 28%, P=0.019). CONCLUSION: In this investigation, approximately half of all patients with prosthetic valves who developed S. aureus bacteremia had definite endocarditis. The risk of endocarditis was independent of the type, location, or age of the prosthetic valve. The mortality of prosthetic valve endocarditis is high. All patients with a prosthetic valve who develop S. aureus bacteremia should be aggressively screened and followed for endocarditis.

Bacteremia↗