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Biomedical subjects

Cathy A Petti

Publications and source records attributed to Cathy A Petti.

At least 19 recordsLinked to original sources
PubMed2006

Discovering potential pathogens among fungi identified as nonsporulating molds.

Fungal infections are increasing, particularly among immunocompromised hosts, and a rapid diagnosis is essential to initiate antifungal therapy. Often fungi cannot be identified by conventional methods and are classified as nonsporulating molds (NSM). We sequenced internal transcribed spacer regions from 50 cultures of NSM and found 16 potential pathogens that can be associated with clinical disease. In selected clinical settings, identification of NSM could prove valuable and have an immediate impact on patient management.

DNA, Fungal↗
PubMed2006

Assessment of the utility of viral culture of cerebrospinal fluid.

Nucleic acid amplification testing is the preferred method to detect enteroviruses and Herpesviridae in cerebrospinal fluid, but clinicians still request viral culture. Review of 22,394 viral cultures of cerebrospinal fluid samples found that <0.1% recovered nonenterovirus, non-Herpesviridae species, suggesting that, when nucleic acid amplification testing is performed, viral culture may have no additional benefit.

Cost-Benefit Analysis↗
PubMed2006

Role of the laboratory in diagnosis of influenza during seasonal epidemics and potential pandemics.

Laboratory diagnosis of influenza is critical to its treatment and surveillance. With the emergence of novel and highly pathogenic avian influenza viruses, the role of the laboratory has been further extended to include isolation and subtyping of the virus to monitor its appearance and facilitate appropriate vaccine development. Recent progress in enhancing testing for influenza promises to both improve the management of patients with influenza and decrease associated health care costs. The present review covers the technological characteristics and utilization features of currently available diagnostic tests, the factors that influence the selection of such tests, and the developments that are essential for pandemic preparedness.

Animals↗
PubMed2006

Application of SmartGene IDNS software to partial 16S rRNA gene sequences for a diverse group of bacteria in a clinical laboratory.

Laboratories often receive clinical isolates for bacterial identification that have ambiguous biochemical profiles by conventional testing. With the emergence of 16S rRNA gene sequencing as an identification tool, we evaluated the usefulness of SmartGene IDNS, a 16S rRNA sequence database and software program for microbial identification. Identification by conventional methods of a diverse group of bacterial clinical isolates was compared with gene sequences interrogated by the SmartGene and MicroSeq databases. Of 300 isolates, SmartGene identified 295 (98%) to the genus level and 262 (87%) to the species level, with 5 (2%) being inconclusive. MicroSeq identified 271 (90%) to the genus level and 223 (74%) to the species level, with 29 (10%) being inconclusive. SmartGene and MicroSeq agreed on the genus for 233 (78%) isolates and the species for 212 (71%) isolates. Conventional methods identified 291 (97%) isolates to the genus level and 208 (69%) to the species level, with 9 (3%) being inconclusive. SmartGene, MicroSeq, and conventional identifications agreed for 193 (64%) of the results. Twenty-seven microorganisms were not represented in MicroSeq, compared to only 2 not represented in SmartGene. Overall, SmartGene IDNS provides comprehensive and accurate identification of a diverse group of bacteria and has the added benefit of being a user-friendly program that can be modified to meet the unique needs of clinical laboratories.

Bacteria↗
PubMed2006

Comparison of multiple shell vial cell lines for isolation of enteroviruses: a national perspective.

BACKGROUND: Isolation of enterovirus in cell culture is still utilized by clinical laboratories, for vaccine research, and for identifying serotypes for disease surveillance. Use of a combination of cell lines is recommended yet this practice has not been rigorously examined for shell vials. OBJECTIVES: To evaluate the growth predilection of enterovirus serotypes for certain shell vial cell lines in clinical samples received at a national reference laboratory. STUDY DESIGN: We retrospectively reviewed results of samples submitted for viral culture over a 3-year period. PMK, BGM, RD, A549, and MRC-5 cell lines grown in shell vials were inoculated and serotyped. RESULTS: Of 55,816 cultures, 1047 (1.9%) yielded enterovirus representing 18 serotypes. Echovirus 7, echovirus 9, and echovirus 30 were the most common serotypes recovered in 2002, 2003, and 2004, respectively. PMK and MRC-5 recovered the majority of enterovirus isolates; the addition of BGM and RD cells increased our recovery rate by 13%. For 52.6% of enteroviral isolates, cytopathic effect was found in only a single cell line. PMK and BGM cells were effective in isolating coxsackieviruses, and RD and MRC-5 were useful particularly in isolating echoviruses. CONCLUSIONS: A combination of shell vial cell lines is still recommended for recovery of enteroviruses.

Animals↗
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↗
PubMed2006

Teaching pediatric laboratory medicine to pathology residents.

CONTEXT: Laboratory data are essential to the medical care of fetuses, infants, children, and adolescents. However, the performance and interpretation of laboratory tests on specimens from these patients, which may constitute a significant component of the workload in general hospitals and integrated health care systems as well as specialized perinatal or pediatric centers, present unique challenges to the clinical pathologist and the laboratory. Therefore, pathology residents should receive training in pediatric laboratory medicine. OBJECTIVE: Children's Health Improvement through Laboratory Diagnostics, a group of pathologists and laboratory scientists with interest and expertise in pediatric laboratory medicine, convened a task force to develop a list of curriculum topics, key resources, and training experiences in pediatric laboratory medicine for trainees in anatomic and clinical pathology or straight clinical pathology residency programs and in pediatric pathology fellowship programs. DATA SOURCES: Based on the experiences of 11 training programs, we have compiled a comprehensive list of pediatric topics in the areas of clinical chemistry, endocrinology, hematology, urinalysis, coagulation medicine, transfusion medicine, immunology, microbiology and virology, biochemical genetics, cytogenetics and molecular diagnostics, point of care testing, and laboratory management. This report also includes recommendations for training experiences and a list of key texts and other resources in pediatric laboratory medicine. CONCLUSIONS: Clinical pathologists should be trained to meet the laboratory medicine needs of pediatric patients and to assist the clinicians caring for these patients with the selection and interpretation of laboratory studies. This review helps program directors tailor their curricula to more effectively provide this training.

Child↗
PubMed2006

Laboratory use in Ghana: physician perception and practice.

Clinical diagnosis of infectious diseases in Africa has been associated with increased misdiagnosis and mortality, but when laboratory testing is available, it remains underused. We retrospectively compared infectious diagnoses, test results, anti-microbial use, and patient cost with laboratory and physician surveys at a teaching hospital in Ghana to evaluate the potential barriers to laboratory use and financial impact for patients. Laboratory capacity was high, but physician survey results and objective data indicated a reliance on clinical judgment and empirical therapy. For the study period, 9-15% of malaria diagnoses, 34-43% of urinary tract infections (UTIs), and 62% of meningitis cases were supported by abnormal laboratory results. For the same period, 0.82-2.09 units of antibiotics were consumed per patient day, and patient cost for antibiotics was 4.8-21.6 times that of laboratory testing. Physician perception regarding the value of diagnostic testing is potentially a major barrier to laboratory use, resulting in empiricism, disproportionate anti-microbial administration, and cost to patients.

Anti-Infective Agents↗
PubMed2005

Laboratory medicine in Africa: a barrier to effective health care.

Providing health care in sub-Saharan Africa is a complex problem. Recent reports call for more resources to assist in the prevention and treatment of infectious diseases that affect this population, but policy makers, clinicians, and the public frequently fail to understand that diagnosis is essential to the prevention and treatment of disease. Access to reliable diagnostic testing is severely limited in this region, and misdiagnosis commonly occurs. Understandably, allocation of resources to diagnostic laboratory testing has not been a priority for resource-limited health care systems, but unreliable and inaccurate laboratory diagnostic testing leads to unnecessary expenditures in a region already plagued by resource shortages, promotes the perception that laboratory testing is unhelpful, and compromises patient care. We explore the barriers to implementing consistent testing within this region and illustrate the need for a more comprehensive approach to the diagnosis of infectious diseases, with an emphasis on making laboratory testing a higher priority.

Africa South of the Sahara↗
PubMed2005

Increased sensitivity of bacterial detection in cerebrospinal fluid by fluorescent staining on low-fluorescence membrane filters.

A membrane-filter-based, fluorescent Gram stain method for bacterial detection in cerebrospinal fluid samples was developed and evaluated as a rapid, sensitive alternative to standard Gram stain protocols. A recently developed, modified version of the aluminium oxide membrane Anopore with low-fluorescence optical properties showed superior performance in this application. Other aspects of the fluorescent Gram stain system that were evaluated include membrane filter selection, strategies to reduce fluorescence fading and the effect of patient blood cells on bacterial detection in the fluorescently stained cerebrospinal fluid samples. The combination of the membrane filter's bacteria-concentrating ability and absolute retention along with high-contrast, fluorescent Gram discriminating dyes enabled rapid bacterial detection and Gram discrimination, with a 1-1.5 order of magnitude increase in the bacterial concentration limit of detection.

Bacteriological Techniques↗
PubMed2005

Controlled clinical comparison of plastic versus glass bottles of BacT/ALERT PF medium for culturing blood from children.

The plastic pediatric BacT/ALERT (bioMérieux, Durham, N.C.) PF (PPF) is a new nonvented aerobic culture medium in a clear plastic bottle designed to prevent breakage. We compared the performance of the new PPF bottle to that of the present glass BacT/ALERT PF bottle for the recovery of microorganisms as well as for the time to detection of growth in samples of blood obtained for culture from children. We found that the PPF and PF bottles were comparable for recovery of microorganisms and that the safety advantage of plastic bottles can be achieved without compromising performance.

Bacteremia↗
PubMed2005

Nalidixic acid-resistant Salmonella enterica serotype Typhi presenting as a primary psoas abscess: case report and review of the literature.

We report an unusual case of Salmonella enterica serotype Typhi presenting as a primary psoas abscess. The isolate tested susceptible to ciprofloxacin but resistant to nalidixic acid in vitro, a pattern associated with fluoroquinolone therapeutic failures. We review the literature for serovar Typhi psoas abscess in the absence of bacteremia and discuss the importance of identifying isolates with reduced susceptibility to fluoroquinolones.

Adult↗
PubMed2005

Controlled clinical comparison of plastic and glass bottles of BacT/ALERT FA medium for culturing organisms from blood of adult patients.

A new, clear-plastic nonvented aerobic FA bottle, designed to prevent breakage, has been developed for the BacT/ALERT blood culture system. We assessed the new plastic FA bottle by comparing its performance with that of the current glass FA bottle for recovery of microorganisms and time to detection of growth in blood samples obtained for culture from adult patients with suspected bloodstream infections. We conclude that the BacT/ALERT plastic and glass FA bottles are comparable for recovery of microorganisms and that the safety advantage of plastic bottles can be achieved without compromising performance.

Adult↗
PubMed2005

Streptococcus pneumoniae antigen test using positive blood culture bottles as an alternative method to diagnose pneumococcal bacteremia.

Recovery of Streptococcus pneumoniae from positive blood culture bottles may be difficult due to autolysis of pneumococci. Therefore, we evaluated the performance of the Binax NOW S. pneumoniae antigen test with samples from positive blood culture bottles and defined the duration of detectable pneumococcal antigen in these bottles. Use of the S. pneumoniae antigen test is an alternative method for identifying S. pneumoniae from positive blood culture bottles and may enable a diagnosis of pneumococcal bacteremia despite negative subcultures.

Antigens, Bacterial↗
PubMed2003

Staphylococcus aureus bacteremia and endocarditis.

Staphylococcus aureus is a leading cause of bacteremia and endocarditis. Over the past several years, the frequency of S aureus bacteremia (SAB) has increased dramatically. This increasing frequency, coupled with increasing rates of antibiotic resistance, has renewed interest in this serious, common infection. S aureus is a unique pathogen because of its virulent properties, its protean manifestations, and its ability to cause endocarditis on architecturally normal cardiac valves. Although the possibility of underlying endocarditis arises in virtually every patient with SAB, only a minority of bacteremic patients will actually have cardiac involvement. Distinguishing patients with S aureus infective endocarditis (IE) from those with uncomplicated SAB is essential, but often difficult. In this review, the authors summarize recent changes in the epidemiology of SAB and IE, discuss the challenges in distinguishing SAB from IE, and discuss current trends in the management of patients with SAB and IE.

Bacteremia↗
PubMed2003

Controlled clinical comparison of BacT/ALERT standard aerobic medium with BACTEC standard aerobic medium for culturing blood.

Standard aerobic media are widely used for culturing blood with the BacT/ALERT (BioMérieux, Inc., Durham, N.C.) (BM) and BACTEC 9240 (BD Diagnostic Systems, Sparks, Md.) (BD) automated continuously monitoring instrument systems. Although similarly composed of soybean-casein digest broths, the formulations of the standard aerobic media available for these instruments differ from each other in supplements and in sodium polyanetholesulfonate concentration. Therefore, we compared the standard aerobic media available for these systems at two university hospitals. Blood samples from adult patients with suspected bloodstream infection were inoculated at the bedside into nonvented BM and BD standard aerobic blood culture bottles and incubated in their respective instruments. The laboratories received 6,743 pairs of bottles that were each filled with 8 to 12 ml of blood. A total of 523 isolates representing true infections were recovered from 257 patients; of these isolates, 348 were recovered from both the BD and the BM bottles, 108 were recovered from the BM bottles only, and 67 were recovered from the BD bottles only (P < 0.005). More staphylococci (P < 0.05), especially coagulase-negative staphylococci (P < 0.05), and yeasts (P < 0.01) were recovered from BM bottles than from BD bottles. Of 291 unimicrobial episodes of bloodstream infection, 220 were detected with both bottles, 41 were detected with the BM bottles only, and 30 were detected with the BD bottles only (difference not significant). Among 335 cultures that were positive in both bottles within the first 72 h of incubation, the median times to detection were 14 h for BM bottles and 13 h for BD bottles. Rates for false-positive results were 0.5% for BM bottles and 0.1% for BD bottles. One BM bottle and seven BD bottles yielded false-negative results. We conclude that the BM medium provides improved recovery of microorganisms, especially staphylococci and yeasts, compared with that provided by the BD medium.

Aerobiosis↗