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Robin Patel

Publications and source records attributed to Robin Patel.

69 records · Page 4Linked to original sources
PubMed2003

Clinical spectrum and laboratory characteristics associated with detection of herpes simplex virus DNA in cerebrospinal fluid.

OBJECTIVE: To determine the clinical, neurologic, and laboratory characteristics of patients with herpes simplex virus (HSV) type 1 (HSV-1) or HSV type 2 (HSV-2) DNA detected in cerebrospinal fluid (CSF) with use of polymerase chain reaction. PATIENTS AND METHODS: Clinical, laboratory, and demographic data were determined from 249 CSF specimens (collected from 247 patients >10 years of age) that tested positive for HSV-1 or HSV-2 DNA at the Mayo Clinic from January 1999 to August 2000. RESULTS: The median age of the 200 patients whose age was available was 70 years vs 40 years for those with HSV-1 or HSV-2 DNA in CSF, respectively. Detailed data were available for 39 and 78 patients with positive polymerase chain reaction results for HSV-1 and HSV-2, respectively. Of those with HSV-1 DNA detected in CSF, 89% had encephalitis, whereas most patients with HSV-2 DNA detected in CSF had findings compatible with meningitis. Only 5 (7%) of 69 patients in whom HSV-2 was detected in CSF had genital lesions at presentation, and none of the assessable patients with HSV-2 who had recurrent meningitis had active genital lesions at presentation. CONCLUSION: The vast majority (82%) of patients with HSV-2 detected in CSF had no history of genital herpes and no lesions at the time of presentation. Polymerase chain reaction assays designed to detect HSV in CSF should detect HSV-1 and HSV-2 and differentiate between HSV-1 and HSV-2.

Academic Medical Centers↗
PubMed2002

Wound infection with Neisseria weaveri and a novel subspecies of pasteurella multocida in a child who sustained a tiger bite.

A 7-year-old girl developed a wound infection as a result of a tiger bite she sustained. DNA sequence analysis revealed that the causative organisms were Neisseria weaveri and what is, to our knowledge, a previously undescribed subspecies of Pasteurella multocida, for which we propose the designation "Pasteurella multocida subspecies tigris subspecies nov."

Animals↗
PubMed2002

Bacteremia due to viridans group Streptococci with diminished susceptibility to Levofloxacin among neutropenic patients receiving levofloxacin prophylaxis.

Despite the use of levofloxacin prophylaxis during the neutropenic period after autologous peripheral blood stem cell transplantation, viridans group (VG) streptococcal bacteremia developed in 6 (16.2%) of 37 patients who underwent transplantation between 1 January and 25 February 2001 at the Mayo Clinic in Rochester, Minnesota. All 6 patients presented with fever and mucositis after a mean of 4.5 days of neutropenia, and 3 developed septic shock. All 6 VG streptococcal isolates from these patients exhibited distinct patterns on pulsed-field gel electrophoresis. All isolates had diminished susceptibility to levofloxacin, 5 to gatifloxacin, and 4 to moxifloxacin. Quinolone resistance was associated with mutations in the quinolone resistance-determining region of GyrA and (for 1 isolate) of ParC. The use of levofloxacin may select VG streptococci with diminished susceptibility to levofloxacin and other quinolones with enhanced activity against gram-positive organisms and, therefore, may not be optimal for preventing VG streptococcal bacteremia in neutropenic patients.

Adult↗
PubMed2002

Preemptive use of oral ganciclovir to prevent cytomegalovirus infection in liver transplant patients: a randomized, placebo-controlled trial.

The use of postdetection antiviral treatment of cytomegalovirus (CMV) as a strategy to prevent infection and disease in solid-organ transplant patients has not been evaluated by placebo-controlled trials. We carried out such a study in 69 patients who had received liver transplants and had positive results of CMV polymerase chain reaction within 8 weeks after transplantation but did not have concomitant CMV infection or disease. These patients were randomly assigned to receive placebo or oral ganciclovir for 8 weeks. CMV infection developed in 21% and disease developed in 12% of placebo recipients (P =.022), compared with 3% and 0%, respectively, among ganciclovir recipients (P =.003). Similarly, in the placebo arm, 55% and 36% of CMV-negative patients who received organs from CMV-positive donors developed CMV infection or disease, respectively (P =.02), compared with 11% and 0% of such patients in the ganciclovir arm (P <.01). Oral ganciclovir administered on CMV detection by PCR prevents CMV infection or disease after liver transplantation.

Administration, Oral↗
PubMed2002

Comparison of line probe assay and DNA sequencing of 5' untranslated region for genotyping hepatitis C virus: description of novel line probe patterns.

We compared a commercial line probe assay (INNO-LiPA HCV II, Innogenetics, N.V., Ghent, Belgium, distributed by Bayer Diagnostics) to an in-house 5' untranslated region direct DNA sequencing method for genotyping hepatitis C virus (HCV). Initial evaluation demonstrated that the INNO-LiPA HCV II assay and sequencing assay assigned the same genotype for 110/132 (83.3%) patient specimens (98 subtype and 12 genotype only identifications). Following the initial evaluation, the INNO-LiPA HCV II assay was used routinely to genotype HCV from patient specimens submitted to our laboratory for genotyping (n = 1,739). During this second part of the study, novel line probe patterns have been noted and interpreted using the in-house direct sequencing assay. Reactivity at bands 1, 2, 3, 4, 5 and 8 (n = 4) or 1, 2, 3, 4, 6 and 7 (n = 2) represented HCV genotype 1. Reactivity at bands 1, 2, 5 and 9 (n = 1) represented HCV genotype 2. Reactivity at bands 1, 2, 5, 9 and 16 (n = 1) represented HCV genotype 4. Reactivity at bands 1, 2, 5, 9, 10, 11 (weak band) and 12 (n = 118) most likely represented HCV genotype 2b. This information should be of use to INNO-LiPA HCV II assay users.

5' Untranslated Regions↗
PubMed2002

Possible overestimation of penicillin resistant Streptococcus pneumoniae colonization rates due to misidentification of oropharyngeal streptococci.

Standard identification of Streptococcus pneumoniae by optochin and bile solubility testing can lead to ambiguous results for certain isolates. Newer bacteriologic identification techniques (e.g., DNA probes) now exist. In a prospective point prevalence study of oropharyngeal S. pneumoniae carriage rates among outpatients, we compared standard organism identification techniques to DNA probe testing. By standard identification criteria, 35 (4%) of 872 isolates were characterized as presumptive S. pneumoniae. Thirty of 35 presumptive isolates were recoverable for DNA probing; 9 (30%) presumptive isolates were confirmed using a DNA probe. The antimicrobial susceptibility pattern of these DNA probe positive isolates closely paralleled that of clinical blood isolates of S. pneumoniae obtained during the study period. The 21 (70%) DNA probe negative isolates, which may represent phylogenetically related species (such as S. mitis or S. oralis), had significantly reduced antimicrobial susceptibility patterns when compared with the DNA probe positive isolates. In colonization studies, if classic criteria (optochin disc zone and bile solubility) are the sole means of identification, S. pneumoniae penicillin resistance rates may be over-reported.

Base Sequence↗
PubMed2002

Preliminary results: outcome of liver transplantation for hepatitis B virus varies by hepatitis B virus genotype.

Hepatitis B virus (HBV) is a leading cause of liver failure throughout the world. HBV has seven different genotypes based on variations within the viral nucleotide sequence. Initially, patients who underwent liver transplantation for HBV had high recurrence rates and poor survival. Recently, improved outcomes have been reported when patients are administered hepatitis B immunoglobulin (HBIg) infusions to maintain high serum hepatitis B surface antibody titers after transplantation. Unfortunately, recurrence rates are still high in patients with active pretransplant HBV replication. The aims of this study are to evaluate the impact of HBV genotype on pretransplantation HBV replication and posttransplantation HBV recurrence rate, morbidity, and mortality. Sera from 22 patients who underwent transplantation for HBV at our center were tested for HBV genotype by an enzyme-linked immunosorbent assay technique using monoclonal antibodies to the pre-S2 region. All patients were administered HBIg after transplantation; 5 patients were administered both lamivudine and HBIg. HBV genotypes were distributed as follows: genotype A (10 patients), genotype C (6 patients), genotype D (5 patients), and genotype E (1 patient). Pretransplantation HBV replication was most common with genotype A (80%), whereas less so with genotypes C (33%) and D (40%). Nine patients (41%) developed recurrent HBV infection: genotype A (2 patients; 20%), genotype C (3 patients; 50%), and genotype D (4 patients; 80%). Mortality was greatest with genotype D (40%). Our data suggest that patients with genotype A have the lowest risk for HBV recurrence despite having the highest rate of pretransplantation HBV viral replication. Patients with genotype D appear to have the highest risk for HBV recurrence and mortality. Additional larger multicenter studies are needed to confirm these findings.

Adult↗
PubMed2002

Antimicrobial release kinetics from polymethylmethacrylate in a novel continuous flow chamber.

Polymethylmethacrylate is used for local delivery of antimicrobials in the treatment of musculoskeletal infections. A novel continuous flow chamber system was designed to measure in vitro antimicrobial release. Three-millimeter beads containing amikacin, gentamicin, tobramycin, or vancomycin [concentration of 7.5% (weight per weight)] were placed individually in a continuous flow chamber with a total volume of 1 mL Kreb's Ringer buffer flowing at 1 mL/hour. Effluent was sampled hourly for 24 hours and then every 2 hours up to 48 hours; antimicrobial concentrations were measured in triplicate by bioassay. The mean peak concentrations were 40.9, 30.1, 30.0, and 19.1 microg/mL; the mean areas under the concentration time curves (Time 0 to infinity) were 263, 327, 110, and 180 hours x microg/mL of antibiotic; and the mean percentages of initial amount of antimicrobial released were 11.7%, 14.5%, 6.6%, and 10.9% for tobramycin, gentamicin, amikacin, and vancomycin, respectively. The results for each polymethylmethacrylate-antimicrobial agent combination were reproducible. In contrast to other in vitro elution systems, this novel system operates under the premise that there is dynamic flow surrounding polymethylmethacrylate in vivo and permits rapid in vitro comparison of the relative release of antimicrobial agents from polymethylmethacrylate.

Amikacin↗
PubMed2002

Multiplex LightCycler PCR assay for detection and differentiation of Bordetella pertussis and Bordetella parapertussis in nasopharyngeal specimens.

A rapid real-time multiplex PCR assay for detecting and differentiating Bordetella pertussis and Bordetella parapertussis in nasopharyngeal swabs was developed. This assay (LC-PCR-IS) targets the insertion sequences IS481 and IS1001 of B. pertussis and B. parapertussis, respectively, and is performed using the LightCycler (Roche Molecular Biochemicals, Indianapolis, Ind.). The analytical sensitivity is less than one organism per reaction. Results for Bordetella culture and/or direct fluorescent antibody testing and a second LightCycler PCR assay (target, pertussis toxin gene) were compared to results of the LC-PCR-IS assay for 111 nasopharyngeal swabs submitted for pertussis testing. Of the specimens, 12 were positive (9 B. pertussis and 3 B. parapertussis) and 68 specimens were negative by all methods. Three other specimens were positive for B. pertussis by at least two of the methods (including the LC-PCR-IS assay), and another 28 specimens were positive for B. pertussis by the LC-PCR-IS assay only. No specimens were negative by the LC-PCR-IS assay and positive by the other methods. A conventional PCR method (target, IS481) was also compared to the LC-PCR-IS assay for a different group of nasopharyngeal swab specimens (n = 96): 44 specimens were positive and 41 specimens were negative for B. pertussis with both PCR methods. Nine specimens were positive for B. pertussis by the LC-PCR-IS assay and negative by the conventional PCR assay, and two specimens were positive for B. pertussis by the conventional PCR assay and negative by the LC-PCR-IS assay. Positivity of the two assays was not significantly different (P = 0.0654). The insertion sequence IS481 is also present in Bordetella holmesii; specimens containing B. holmesii may yield false-positive results. The LC-PCR-IS assay takes approximately 45 min to complete post-nucleic acid extraction, compared to 24 h for the conventional PCR assay previously used in our laboratory. The LC-PCR-IS assay is easier to perform than the conventional PCR assay, and the closed system decreases the chance of contamination. All of these characteristics represent a significant improvement in the detection of B. pertussis and B. parapertussis in nasopharyngeal specimens.

Bordetella↗
PubMed2002

Reevaluation of Streptococcus bovis endocarditis cases from 1975 to 1985 by 16S ribosomal DNA sequence analysis.

Studies that detected an association between Streptococcus bovis endocarditis and colon carcinoma have not taken into account the recently identified genetic diversity among organisms historically classified as S. bovis. With near full-length 16S ribosomal DNA sequence analysis, organisms cultured from the blood of endocarditis patients at the Mayo Clinic from 1975 to 1985 and previously identified as S. bovis or streptococcus group D nonenterococci were shown to represent S. bovis biotypes I (11 isolates) and II/2 (1 isolate), S. salivarius (1 isolate), and S. macedonicus (1 isolate). Two of the S. bovis biotype I cases were associated with colon cancer. Whether S. bovis biotype II or other organisms closely related to and historically identified as S. bovis (e.g., S. macedonicus) are associated with malignant (or premalignant) colon lesions in humans remains to be definitively determined.

Aged↗
PubMed2002

Comparative evaluation of the VERSANT HCV RNA 3.0, QUANTIPLEX HCV RNA 2.0, and COBAS AMPLICOR HCV MONITOR version 2.0 Assays for quantification of hepatitis C virus RNA in serum.

A comparison of quantitative results expressed in hepatitis C virus (HCV) international units per milliliter, obtained from the VERSANT HCV RNA 3.0 (bDNA-3.0) assay, the QUANTIPLEX HCV RNA 2.0 (bDNA-2.0) assay, and the COBAS AMPLICOR HCV MONITOR version 2.0 (HCM-2.0) test was performed. A total of 168 patient specimens submitted to the Mayo Clinic Molecular Microbiology Laboratory for HCV quantification or HCV genotyping were studied. Of the specimens tested, 97, 88, and 79% yielded quantitative results within the dynamic range of the bDNA-3.0, bDNA-2.0, and HCM-2.0 assays, respectively. Overall, there was substantial agreement between the results generated by all three assays. A total of 15 out of 29 (52%) of the specimens determined to contain viral loads of <31,746 IU/ml by the bDNA-3.0 assay were categorized as containing viral loads within the range of 31,746 to 500,000 IU/ml by the bDNA-2.0 assay. Although substantial agreement was noted between the results generated by the bDNA-2.0 and bDNA-3.0 assays, a bias toward higher viral titer by the bDNA-2.0 assay was noted (P = 0.001). Likewise, although substantial agreement was noted between the results generated by the HCM-2.0 and bDNA-3.0 assays, a bias toward higher viral titer by the bDNA-3.0 assay was noted (P < or = 0.001). The discrepancy between the HCM-2.0 and bDNA-3.0 results was more pronounced when viral loads were >500,000 IU/ml and resulted in statistically significant differences (P < or = 0.001) in determining whether viral loads were above or below 800,000 IU/ml of HCV RNA, the proposed threshold value for tailoring the duration of combination therapy. The expression of quantitative values in HCV international units per milliliter was a strength of both the bDNA-3.0 and HCM-2.0 assays.

Branched DNA Signal Amplification Assay↗