High frequency of false positive IgM immunoblots for Borrelia burgdorferi in clinical practice.

Although it is known that two-tier serologic testing for Lyme disease may be associated with false positive results on the IgM immunoblot, this problem has never been systematically studied in the clinical practice setting. In a retrospective investigation of patients referred to the private adult practice of an Infectious Diseases physician for possible for Lyme disease, 50 of 182 patients (27.5%, 95% CI: 21.1-34.6) were found to have a false positive IgM immunoblot. 78.0% of these patients had received unnecessary antibiotic therapy. False positive results were not restricted to any single commercial laboratory. Research on alternative testing strategies that eliminate the IgM immunoblot entirely is warranted.

Quantitation of cell-associated borrelial DNA in the blood of Lyme disease patients with erythema migrans.

Bloodstream invasion is an important event in the pathogenesis of the more serious manifestations of Lyme disease. The number of spirochetes in the blood of infected patients, however, has not been determined, and, therefore, it is unknown whether the number of spirochetes can be correlated with particular clinical or laboratory features. This study was designed to measure the level of Borrelia burgdorferi in the plasma of Lyme disease patients and correlate these levels with selected clinical and laboratory findings. Nested and quantitative polymerase chain reaction (qPCR) was employed to detect cell-associated flaB gene DNA in the plasma of untreated early Lyme disease patients with erythema migrans (EM). Twenty-nine (45.3%) of 64 patients had evidence of B. burgdorferi in their plasma by at least one of the PCR methods. For the 22 qPCR-positive patients, the mean number of flaB gene copies per mL of plasma was 4,660, with a range of 414 to 56,000. The number of flaB gene copies did not significantly correlate with any of the clinical, demographic, or laboratory variables assessed. For reasons discussed, we suggest caution in extrapolating an estimate of the number of viable Borrelia in plasma from the observed number of flaB copies.

Cryptococcal infection presenting as cellulitis in a renal transplant recipient.

Opportunistic infections of skin and soft tissue represent a rare but serious complication following solid organ transplantation. We report a case of severe soft tissue infection caused by Cryptococcus neoformans in a renal transplant recipient. Physicians need to consider the possibility of opportunistic pathogens when managing infections in immunocompromised hosts, especially when symptoms persist despite seemingly appropriate empiric antimicrobial therapy. Tissue sampling for histological and microbiological evaluation is usually necessary to establish a diagnosis.

Practice parameter: treatment of nervous system Lyme disease (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology.

OBJECTIVE: To provide evidence-based recommendations on the treatment of nervous system Lyme disease and post-Lyme syndrome. Three questions were addressed: 1) Which antimicrobial agents are effective? 2) Are different regimens preferred for different manifestations of nervous system Lyme disease? 3) What duration of therapy is needed? METHODS: The authors analyzed published studies (1983-2003) using a structured review process to classify the evidence related to the questions posed. RESULTS: The panel reviewed 353 abstracts which yielded 112 potentially relevant articles that were reviewed, from which 37 articles were identified that were included in the analysis. CONCLUSIONS: There are sufficient data to conclude that, in both adults and children, this nervous system infection responds well to penicillin, ceftriaxone, cefotaxime, and doxycycline (Level B recommendation). Although most studies have used parenteral regimens for neuroborreliosis, several European studies support use of oral doxycycline in adults with meningitis, cranial neuritis, and radiculitis (Level B), reserving parenteral regimens for patients with parenchymal CNS involvement, other severe neurologic symptomatology, or failure to respond to oral regimens. The number of children (> or =8 years of age) enrolled in rigorous studies of oral vs parenteral regimens has been smaller, making conclusions less statistically compelling. However, all available data indicate results are comparable to those observed in adults. In contrast, there is no compelling evidence that prolonged treatment with antibiotics has any beneficial effect in post-Lyme syndrome (Level A).

In vivo and in vitro studies on Anaplasma phagocytophilum infection of the myeloid cells of a patient with chronic myelogenous leukaemia and human granulocytic ehrlichiosis.

AIMS: The occurrence of human granulocytic ehrlichiosis (HGE) in a patient with chronic myelogenous leukaemia (CML) provided an opportunity to study whether Anaplasma phagocytophilum, the aetiological agent of HGE, infects mature or immature cells, both in vivo and in vitro. METHODS: Diagnosis of HGE was confirmed by culture, polymerase chain reaction (PCR), detection of intragranulocytic inclusions, and serology. The infection rates of different myelogenous stages of granulocytic differentiation were determined by microscopy. Anaplasma phagocytophilum infection of the bone marrow was analysed by PCR, culture, and microscopy. In addition, the in vitro growth of A phagocytophilum in the patient's granulocytes and in HL-60 cells (a promyelocytic leukaemia cell line) was compared. RESULTS: Pretreatment blood smears showed that mature granulocytic cells had a higher infection rate with A phagocytophilum than did immature cells. In the original inoculation of the patient's cells into HL-60 cells to isolate A phagocytophilum, the bacterium grew faster in the patient's leukaemic cells than in HL-60 cells. Anaplasma phagocytophilum inclusions were rarely seen in bone marrow granulocytes and PCR was negative. In vitro, two A phagocytophilum isolates grew faster in the patient's granulocytes than in HL-60 cells. CONCLUSIONS: The superior growth in CML cells compared with HL-60 cells suggests that A phagocytophilum preferentially infects mature granulocytes. The higher infection rate of the patient's mature versus immature granulocytes before treatment and the minimal level of infection of the patient's bone marrow support this. It is possible that the primary site of infection in HGE is the peripheral mature granulocytic population.

Laboratory diagnostic techniques for patients with early Lyme disease associated with erythema migrans: a comparison of different techniques.

Recently, a number of refinements in diagnostic modalities for detection of Borrelia burgdorferi infection have been developed. These include large-volume blood cultures, quantitative polymerase chain reaction (PCR) techniques, and 2-stage serologic testing. In the present study, we compared 6 diagnostic modalities in 47 adult patients who had a clinical diagnosis of erythema migrans. Quantitative PCR on skin biopsy-derived material was the most sensitive diagnostic method (80.9%), followed by 2-stage serologic testing of convalescent-phase samples (66.0%), conventional nested PCR (63.8%), skin culture (51.1%), blood culture (44.7%), and serologic testing of acute-phase samples (40.4%). Results of all assays were negative for 3 patients (6.4%). We conclude that the clinical diagnosis of erythema migrans is highly accurate in an area where B. burgdorferi is endemic if it is made by experienced health care personnel, but some patients with this diagnosis may not have B. burgdorferi infection. No single diagnostic modality is suitable for detection of B. burgdorferi in every patient with erythema migrans.

Asymptomatic Borrelia burgdorferi infection.

Little is known about the natural history of asymptomatic Borrelia burgdorferi infection. Our analysis of the asymptomatic infections diagnosed serologically in a recent OspA vaccine trial conducted in the United States (N Engl J Med 1998;339: 209-215), suggests that the natural history of this event is more benign than that reported for untreated patients with erythema migrans (Ann Intern Med 1987;107: 725-731). We hypothesize that this is due either to incorrect diagnosis since the specificity of the serologic criteria used to diagnose asymptomatic infection in the vaccine study is unknown, or to infection with non-pathogenic strains of B. burgdorferi. Increasing evidence indicates that the invasive potential of strains of B. burgdorferi varies according to the specific subtype. Theoretically, a serologic testing method could be devised which would distinguish infection with invasive versus non-invasive strains of B. burgdorferi, and allow testing of the second hypothesis.

Dexamethasone inhibits CD4 T cell deletion mediated by macrophages from human immunodeficiency virus-infected persons.

Prednisolone slows the loss of CD4 T cells in individuals with human immunodeficiency virus (HIV) disease and inhibits antigen-induced apoptosis of recently HIV-infected CD4 cells in vitro. This study investigated whether dexamethasone inhibits the ability of macrophages to delete CD4 T cells via anti-CD4 antibody or immune-complexed HIV envelope protein gp120. Peripheral blood mononuclear cells from HIV-negative persons were incubated with CD4-reactive ch412 monoclonal antibody or with gp120/IgG immune complexes and resident macrophages, with and without dexamethasone. Dexamethasone inhibited CD4 cell deletion in a dose-dependent manner. The deletion of normal CD4 cells by macrophages from HIV-infected patients also was inhibited by dexamethasone. Furthermore, up-regulation of CD95 expression on T cells exposed to anti-CD4 and gp120/IgG, which predisposes T cells to CD95-mediated apoptosis, is inhibited by dexamethasone in a dose-dependent fashion. Dexamethasone inhibits the macrophage-mediated deletion of CD4 lymphocytes in HIV-infected persons.

Western blot analysis of sera reactive to human monocytic ehrlichiosis and human granulocytic ehrlichiosis agents.

Laboratory diagnosis of human ehrlichioses is routinely made by an indirect immunofluorescence assay (IFA) using cultured ehrlichia-infected whole cells as antigen. Concern has been raised that incorrect diagnoses of human monocytic ehrlichiosis (HME) or human granulocytic ehrlichiosis (HGE) may be made on the basis of serologic cross-reactivity between Ehrlichia chaffeensis and the agent of HGE. The present study examined whether two recombinant major outer membrane proteins, rP30 and rP44, that were previously shown to be sensitive and specific serodiagnostic antigens for HME and HGE, respectively, could be used to discriminate IFA dually reacting sera. Thirteen dually IFA-reactive sera, three sera that were IFA positive only with E. chaffeensis, and three sera that were IFA positive only with the HGE agent were examined by Western immunoblot analysis using purified whole organisms and recombinant proteins as antigens. All 16 E. chaffeensis IFA-positive sera reacted with rP30. However, none of these sera reacted with rP44, regardless of IFA reactivity with the HGE agent. The three HGE-agent-only IFA-positive sera reacted only with rP44, not with rP30. Western immunoblotting using purified E. chaffeensis and the HGE agent as antigens suggested that heat shock and other proteins, but not major outer membrane proteins, cross-react between the two organisms. Therefore, Western immunoblot analysis using rP44 and rP30 may be useful in discriminating dually HME and HGE IFA-reactive sera.

Costs and savings associated with infection control measures that reduced transmission of vancomycin-resistant enterococci in an endemic setting.

OBJECTIVE: To determine the costs and savings of a 15-component infection control program that reduced transmission of vancomycin-resistant enterococci (VRE) in an endemic setting. DESIGN: Evaluation of costs and savings, using historical control data. SETTING: Adult oncology unit of a 650-bed hospital. PARTICIPANTS: Patients with leukemia, lymphoma, and solid tumors, excluding bone marrow transplant recipients. METHODS: Costs and savings with estimated ranges were calculated. Excess length of stay (LOS) associated with VRE bloodstream infection (BSI) was determined by matching VRE BSI patients with VRE-negative patients by oncology diagnosis. Differences in LOS between the matched groups were evaluated using a mixed-effect analysis of variance linear-regression model. RESULTS: The cost of enhanced infection control strategies for 1 year was $116,515. VRE BSI was associated with an increased LOS of 13.7 days. The savings associated with fewer VRE BSI ($123,081), fewer patients with VRE colonization ($2,755), and reductions in antimicrobial use ($179,997) totaled $305,833. Estimated ranges of costs and savings for enhanced infection control strategies were $97,939 to $148,883 for costs and $271,531 to $421,461 for savings. CONCLUSION: The net savings due to enhanced infection control strategies for 1 year was $189,318. Estimates suggest that these strategies would be cost-beneficial for hospital units where the number of patients with VRE BSI is at least six to nine patients per year or if the savings from fewer VRE BSI patients in combination with decreased antimicrobial use equalled $100,000 to $150,000 per year.

Yield of large-volume blood cultures in patients with early Lyme disease.

To improve yield, 6 3-mL plasma cultures (18 mL total) were established for adult patients with early Lyme disease associated with erythema migrans. Borrelia burgdorferi was recovered from the blood of 22 (44.0%) of 50 evaluable patients. The recovery rate per plasma culture and the frequency of positive results for plasma cultures for individual patients were consistent with a level of spirochetemia of approximately 0.1 cultivable cell/mL of whole blood. Our findings suggest that, if further improvements in the yield of blood cultures are possible, they probably will depend on enhancing the sensitivity of the culture method rather than increasing the volume of material cultured.

A first-tier rapid assay for the serodiagnosis of Borrelia burgdorferi infection.

BACKGROUND: The present recommendation for the serologic diagnosis of Lyme disease is a 2-tier process in which a serum sample with a positive or equivocal result by an enzyme-linked immunosorbent assay (ELISA) or immunofluorescent assay is then followed by supplemental testing by Western blot. Our laboratory has developed recombinant chimeric proteins composed of key Borrelia epitopes. These novel antigens are consistent and are easily standardized. METHODS: We adapted these recombinant proteins into a new immunochromatographic format that can be used as a highly sensitive and specific first-tier assay that can be used to replace the ELISA or immunofluorescent assay. RESULTS: This rapid test was equally sensitive (P>.05) and more specific (P<.05) than a frequently used commercial whole cell ELISA. The overall clinical accuracy achieved on agreement studies among 3 Lyme research laboratories on clinically defined serum panels was shown to be statistically equivalent to the commercial ELISA. The assay can detect anti-Borrelia burgdorferi antibodies in either serum or whole blood. CONCLUSION: This sensitive and specific rapid assay, which is suited for the physician's office, streamlines the 2-tier system by allowing the physician to determine if a Western blot is necessary at the time of the initial office visit.

Characterization of Borrelia burgdorferi isolated from erythema migrans lesions: interrelationship of three molecular typing methods.

Genetic diversity among Borrelia burgdorferi isolates recovered from the skin of Lyme disease patients was assessed by ribosomal DNA (rDNA) spacer restriction fragment length polymorphism analysis, genomic restriction site polymorphism analysis, and plasmid content analysis. There was a significant association between the three rDNA spacer types, the six pulsed-field gel types, and plasmid content (P < 0.001). The association between distinct chromosomal and plasmid markers implies a clonal origin for each genotype.