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Robin Patel

Publications and source records attributed to Robin Patel.

At least 55 records · Page 3Linked to original sources
PubMed2004

Synovial fluid leukocyte count and differential for the diagnosis of prosthetic knee infection.

PURPOSE: Criteria for the interpretation of synovial fluid are well established for native joint disorders but lacking for the evaluation of prosthetic joint failure. Our aim was to define cutoff values for synovial fluid leukocyte count and neutrophil percentage for differentiating aseptic failure and prosthetic joint infection. METHODS: We performed a prospective study of 133 patients in whom synovial fluid specimens were collected before total knee arthroplasty revision between January 1998 and December 2003. Patients with underlying inflammatory joint disease were excluded. RESULTS: Aseptic failure was diagnosed in 99 patients and prosthetic joint infection was diagnosed in 34 patients. The synovial fluid leukocyte count was significantly higher in patients with prosthetic joint infection (median, 18.9 x 10(3)/microL; range, 0.3 to 178 x 10(3)/microL) than in those with aseptic failure (median, 0.3 x 10(3)/microL; range, 0.1 to 16 x 10(3)/microL; P <0.0001); the neutrophil percentage was also significantly higher in patients with prosthetic joint infection (median [range], 92% [55% to 100%] vs. 7% [0% to 79%], P <0.0001). A leukocyte count of >1.7 x 10(3)/microL had a sensitivity of 94% and a specificity of 88% for diagnosing prosthetic joint infection; a differential of >65% neutrophils had a sensitivity of 97% and a specificity of 98%. Staphylococcus aureus was the only pathogen associated with leukocyte counts >100 x 10(3)/microL. CONCLUSION: A synovial fluid leukocyte differential of >65% neutrophils (or a leukocyte count of >1.7 x 10(3)/microL) is a sensitive and specific test for the diagnosis of prosthetic knee infection in patients without underlying inflammatory joint disease.

Adult↗
PubMed2004

Molecular Methods in the Diagnosis of Endocarditis.

Advances in molecular microbiologic diagnostics have yielded new tools to diagnose infective endocarditis. These tools can detect microorganisms that are difficult to grow or are uncultivable, because of prior antimicrobial therapy or because of innate characteristics of the microorganisms. This paper reviews molecular microbiologic diagnostic techniques and their role in the diagnosis of infective endocarditis.

Journal Article↗
PubMed2004

In vitro activity of BAL9141 against clinical isolates of gram-negative bacteria.

The minimum inhibitory concentration and minimum bactericidal concentration of BAL9141 against 150 clinical isolates of gram-negative bacteria were determined and compared to those of cefepime and ceftriaxone. BAL9141 exhibited comparable activity to cefepime and ceftriaxone against Haemophilus influenzae, Klebsiella pneumoniae, and extended-spectrum beta-lactamase nonproducing Enterobacter cloacae, and comparable activity to cefepime against Pseudomonas aeruginosa.

Cephalosporins↗
PubMed2004

Mycobacterium celatum, an emerging pathogen and cause of false positive amplified Mycobacterium tuberculosis direct test.

Mycobacterium celatum is a recently described organism. Herein we describe a case of M. celatum lymphadenitis in an immunocompetent child and the first reported case of a M. celatum infection (lung abscess) in a transplant recipient. A literature review identified 19 other cases of M. celatum infection. Fifteen occurred in patients with the acquired immunodeficiency syndrome. Of these, nine were disseminated and six were localized (primarily to the lungs). The remaining 4 patients were immunocompetent and had localized infection (pneumonitis or lymphadenitis). Diagnosis of M. celatum infection can be challenging as M. celatum can cause false-positive results with the current version of the Amplified Mycobacterium tuberculosis Direct Test (Gen-Probe, San Diego, CA.). Definitive identification is available by DNA sequencing or high-performance liquid chromatography. M. celatum can cause infection in immunocompromised and immunocompetent hosts.

AIDS-Related Opportunistic Infections↗
PubMed2004

Release of daptomycin from polymethylmethacrylate beads in a continuous flow chamber.

Because daptomycin is active against Gram-positive cocci, it may be useful in the treatment and prevention of bone and joint infections when incorporated into polymethylmethacrylate (PMMA). The release kinetics of daptomycin from PMMA were studied in a continuous flow chamber designed to simulate in vivo conditions. Three-millimeter beads containing 2.5%, 7.5%, and 15.0% daptomycin (weight daptomycin per weight PMMA) were individually placed in a chamber with 1 mL Krebs Ringer buffer flowing at 1 mL/hour. The majority of daptomycin was released in the first 24 hours. The mean peak concentrations were 13.4, 62.3, and 146.7 microg/mL; the mean AUC0-infinity were 30, 272, and 1204 h x microg/mL; and the mean percentages of daptomycin released were 6%, 18%, and 42% for the beads containing 2.5%, 7.5%, and 15.0% daptomycin, respectively. Daptomycin is released from PMMA in a continuous flow chamber at a rate similar to that previously determined by our laboratory for vancomycin.

Anti-Bacterial Agents↗
PubMed2004

Gentamicin and vancomycin do not impair experimental fracture healing.

The purpose of this study was to determine whether gentamicin or vancomycin impair experimental fracture healing in rats. Forty-one male Wistar rats were divided into three groups, receiving either 1.5 mg/kg of gentamicin intramuscularly twice daily for 3 weeks (n = 15), 25 mg/kg of vancomycin intraperitoneally twice daily for 3 weeks (n = 14), or no treatment (n = 12), starting 7 days after production of closed, nondisplaced, bilateral femoral fractures. The mean 30 minute serum concentrations of gentamicin and vancomycin were 4.5 microg/mL and 35.1 microg/mL, respectively. Biomechanical and radiographic studies were used to evaluate fracture healing. Torsional strength testing of fracture callus exposed to gentamicin and vancomycin was similar (437 and 424 N-mm, respectively) to controls (334 N-mm). Radiographs showed similar healing in control animals (Goldberg score, 2.3) compared with rats treated with gentamicin and vancomycin (Goldberg score, 2.6 in both groups). Results of this study do not show impaired healing of experimental fractures after exposure to gentamicin or vancomycin (such as has been reported after exposure to quinolones).

Animals↗
PubMed2004

Antimicrobial susceptibility patterns among viridans group streptococcal isolates from infective endocarditis patients from 1971 to 1986 and 1994 to 2002.

To determine whether changes in antimicrobial resistance have occurred among viridans group streptococci, we retrospectively examined 50 viridans group streptococcal isolates recovered from patients with infective endocarditis over 3 decades. Resistance rates (percent resistant isolates 1971 to 1986 and 1994 to 2002) were as follows: levofloxacin, 0 and 9; penicillin and clindamycin, 0 and 4; and erythromycin and azithromycin, 11 and 26, respectively.

Anti-Bacterial Agents↗
PubMed2004

icaA is not a useful diagnostic marker for prosthetic joint infection.

A collection of 99 staphylococcal isolates associated with prosthetic joint infection and 23 coagulase-negative staphylococci isolated from noninfected arthroplasty-associated specimens were screened in order to determine whether the presence of icaA could be used to distinguish between pathogens and nonpathogens. All Staphylococcus aureus prosthetic joint infection isolates (n = 55) were icaA positive. A total of 46% (20 out of 44) of coagulase-negative staphylococcal prosthetic joint infection isolates were icaA positive, and 30% (7 out of 23) of arthroplasty-associated non-prosthetic joint infection-associated coagulase-negative staphylococcal isolates were icaA positive (P = 0.23). Certain coagulase-negative Staphylococcus species appeared more likely to be isolated as either arthroplasty-associated non-prosthetic joint infection-associated isolates (e.g., Staphylococcus warneri and Staphylococcus hominis) or pathogens (e.g., Staphylococcus lugdunensis). The presence of icaA in a coagulase-negative staphylococcal isolate associated with an arthroplasty is not a useful diagnostic indicator of pathogenicity.

Arthroplasty↗
PubMed2003

Comparison of the VERSANT HCV RNA qualitative assay (transcription-mediated amplification) and the COBAS AMPLICOR hepatitis C virus test, version 2.0, in patients undergoing interferon-ribavirin therapy.

Hepatitis C virus (HCV)-infected patients were tested for the presence of HCV RNA using two qualitative assays at various time points during interferon-ribavirin therapy. Among patients treated for 48 weeks, transcription-mediated amplification and the COBAS AMPLICOR Hepatitis C Virus Test results at Week 24 predicted subsequent virologic non-response or virologic relapse in 12/15 (80%) and 8/15 (53%) patients, respectively.

Antiviral Agents↗
PubMed2003

Characterization of hepatitis B virus surface antigen and polymerase mutations in liver transplant recipients pre- and post-transplant.

We evaluated serum samples from 18 chronic hepatitis B virus (HBV) patients who underwent liver transplantation for the presence of HBV polymerase and S gene mutations and HBV genotype using a new commercially available sequencing assay. All three patients with hepatitis B immune globulin (HBIG) treatment failure followed by nucleoside analogue treatment failure were infected with HBV genotype C; a pre-existing HBV S antigen (HBsAg) mutation (sD144A) was identified in one patient pretransplant, while sG145R mutations emerged in the other two patients post-transplant. These HBsAg mutations persisted for the duration of the study (5-6 years), despite the absence of HBIG administration for a 4-5-year period. Significant viral polymerase mutations (rtL180M and rtM204I/V) also emerged in all of these patients following treatment with lamivudine and/or famciclovir. Four of six patients with HBIG breakthrough without nucleoside analogue treatment failure yielded potentially significant HBsAg mutations post transplant. These data do not support previous reports highlighting the disappearance of HBsAg mutants in liver transplant recipients after discontinuation of HBIG. Determination of HBV genotype, as well as identification of HBV polymerase and S gene mutations in liver transplant candidates may be warranted to optimize HBV management strategies post transplant.

Chronic Disease↗
PubMed2003

Clinical impact of vancomycin-resistant enterococci.

In humans, vancomycin-resistant enterococci (VRE) most commonly result in intestinal colonization, which does not result in symptoms, may persist for a long time and serves as a reservoir for transmission of VRE to other patients. Certain VRE-colonized patients are at risk of infection, including haematology and oncology patients, patients in intensive care units and recipients of solid (especially abdominal) organ transplants. Controlling the spread of VRE colonization and preventing colonized patients from becoming infected are important aims. Ramoplanin is a member of a new class of antimicrobial agents; it may have a role in preventing infection in patients colonized with VRE.

Anti-Bacterial Agents↗
PubMed2003

Levofloxacin and trovafloxacin inhibition of experimental fracture-healing.

We previously have shown that experimental fractures exposed to ciprofloxacin have diminished fracture healing. The purpose of this study was to assess the effect of levofloxacin and trovafloxacin on experimental fracture healing to test the hypothesis that diminished fracture healing is a quinolone class effect. Sixty-one male Wistar rats were divided into three groups, which received 25 mg/kg of levofloxacin twice daily for 3 weeks, 35 mg/kg of trovafloxacin twice daily for 3 weeks, or no treatment, beginning 7 days after production of closed, nondisplaced, bilateral femoral fractures. The mean peak serum concentrations of levofloxacin and trovafloxacin drawn 30 minutes after administration were 6.9 and 7.0 microg/mL, respectively. Radiographic, histologic, and biomechanical studies were used to evaluate fracture healing. Torsional strength testing of fracture callus exposed to levofloxacin and trovafloxacin revealed a decrease in strength (299 and 257 N-mm, respectively) as compared with controls (364 N-mm). Radiographs revealed significantly more advanced healing in control animals (Goldberg score of 2.1) compared with the fractures in the rats treated with levofloxacin and trovafloxacin (Goldberg score of 1.5 in both groups). Fracture calluses in the animals treated with levofloxacin and trovafloxacin showed a lower histologic grade (5.3 and 3.5, respectively) as compared with control animals (7.5) representing a less mature callus with the presence of more cartilage and less woven bone. These data suggest that experimental fractures systemically exposed to levofloxacin or trovafloxacin have diminished healing during the early stages of fracture repair. The administration of quinolones during early fracture repair may compromise fracture healing in humans.

Animals↗
PubMed2003

Molecular and antibiofilm approaches to prosthetic joint infection.

The majority of patients with prosthetic joint replacement (arthroplasty) experience dramatic relief of pain and restoration of satisfactory joint function. In the United States, more than.5 million people have a primary arthroplasty each year. Less than 10% of prosthesis recipients have complications develop during their lifetime, commonly as a result of aseptic biomechanical failure, followed by prosthetic joint infection. The pathogenesis of prosthetic joint infection is related to bacteria in biofilms, in which they are protected from antimicrobial killing and host responses rendering these infections difficult to eradicate. Current microbiology laboratory methods for diagnosis of prosthetic joint infection depend on isolation of a pathogen by culture. However, these methods have neither ideal sensitivity nor ideal specificity. Therefore, culture-independent molecular methods have been used to improve the diagnosis of prosthetic joint infection. In the research setting, detection of 16S ribosomal deoxyribonucleic acid by polymerase chain reaction has been used in the molecular diagnosis of prosthetic joint infection. Various antibiofilm strategies directed at disruption of adherent bacteria are the focus of intense research to improve the detection of biofilm organisms and their eradication. In this article, molecular and antibiofilm approaches to prosthetic joint infection are reviewed.

Attachment Sites, Microbiological↗
PubMed2003

Evaluation of the MagNA pure LC instrument for extraction of hepatitis C virus RNA for the COBAS AMPLICOR Hepatitis C Virus Test, version 2.0.

The COBAS AMPLICOR system has played a major role in the transition of molecular diagnostics from research to routine clinical laboratory use by automating the nucleic acid amplification and detection processes. However, sample preparation remains a labor-intensive portion of the procedure. In this study, we evaluated the performance of the COBAS AMPLICOR Hepatitis C Virus Test, version 2.0 (Roche Molecular Systems, Branchburg, N.J.) following manual hepatitis C virus (HCV) RNA extraction versus automated extraction with the MagNA Pure LC instrument (Roche Applied Science, Indianapolis, Ind.). Parallel replicate testing was performed with standard dilutions of 100, 75, 60, and 0 HCV IU/ml and 153 clinical specimens. An analytical sensitivity of 75 IU/ml was achieved with either the manual or the standard-volume (200 microl) automated extraction methodologies (25 of 26 [96.2%]; 95% confidence interval [95% CI], 80.4 to 99.9), whereas the clinical sensitivity and specificity were both 100% with either extraction method. A large-volume (1 ml) automated extraction method was also evaluated with standard dilutions of 40, 25, 10, and 0 IU/ml and the same 153 clinical specimens. The analytical sensitivity of the COBAS AMPLICOR assay with the large-volume extraction method was 25 HCV IU/ml (26 of 26 [100%]; 95% CI, 86.8 to 100), whereas the clinical sensitivity and specificity were both 100%. The MagNA Pure LC instrument is a versatile, labor-saving platform capable of integration with minimal modification of the existing assay procedure. The increased sensitivity of the COBAS AMPLICOR Hepatitis C Virus Test, version 2.0 performed in conjunction with large-volume HCV RNA extraction may be important in HCV diagnostic testing as new therapeutic strategies evolve.

Hepacivirus↗