Charles Pavia

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.

Blood Cultures for Patients with Extracutaneous Manifestations of Lyme Disease in the United States

Spirochetemia in US patients with extracutaneous manifestations of Lyme disease is not well documented. In this study, blood culture results were positive for 5 (19.2%; 95% confidence interval, 6.6%-39.4%) of 26 untreated adult patients with extracutaneous manifestations but only for patients with clinical evidence for a short duration of infection.

Efficacy of Short-Course Ceftriaxone Therapy for Borrelia burgdorferi Infection in C3H Mice

ABSTRACT Ceftriaxone is highly effective clinically in patients with Lyme disease. We studied a representative invasive human isolate of Borrelia burgdorferi for which the MBC of ceftriaxone was 0.050 μg/ml. A once-per-day dosage regimen of ceftriaxone (50 mg/kg/dose) administered intramuscularly for 5 days was 100% effective in sterilizing tissue samples of C3H mice infected with this strain of B. burgdorferi, regardless of whether the mice were being treated concomitantly with a corticosteroid. Administration of the same five doses of ceftriaxone at 6-h intervals over just 24 h was also 100% effective. These experiments suggest that shorter courses of antibiotics than those currently recommended should be considered for study in patients with early uncomplicated Lyme disease.

Activity of Sera from Patients with Lyme Disease Against Borrelia burgdorferi

Sera from patients with Lyme disease were evaluated for their ability to kill Borrelia burgdorferi in vivo and in vitro. Separate groups of C3H mice received sera from seropositive humans with early- or late-stage Lyme disease or from seronegative controls. Eighteen to 24 hours after passive transfer of sera, the mice were challenged with 100,000 low-passage B. burgdorferi strain B31 or CA287 organisms. Sera from subjects with late-stage Lyme disease protected the mice against infection after challenge with B. burgdorferi, but sera from subjects with early-stage Lyme disease were not protective. Late-stage sera also inhibited the growth of B. burgdorferi in microcultures on Barbour-Stoenner-Kelly media better than early-stage sera. Immunoblot analysis revealed that the protective properties of late-stage sera were associated with a response of antibodies to multiple proteins. This response included strong reactivity with the outer-surface proteins A and B, which was lacking in early-stage sera.

An indirect hemagglutination antibody test to detect antibodies to Borrelia burgdorferi in patients with Lyme disease.

An indirect hemagglutination antibody (IHA) test was evaluated for its ability to detect borrelial antibodies in serum samples from patients with Lyme disease. The key test reagent developed for this antibody detection system was tannic acid-treated and glutaraldehyde-fixed sheep red blood cells (SRBC) containing Borrelia burgdorferi (Bb) antigens attached to the outer surface of the SRBC. In order to establish suitable cut-off titers, initial specificity and sensitivity measurements were made using sera from 100 anonymous healthy volunteers and 30 additional pre-determined samples known to be non-reactive or reactive for Lyme disease or syphilis. These results were compared with those obtained using a commercially available ELISA. At titers >/=64, the IHA test had a combined 98% specificity and 100% sensitivity for these 130 serum samples, 30 of which were known positives or negatives, whereas the ELISA was less specific (93%) and much less sensitive (80%). Subsequent testing was performed on sera from 65 patients with the erythema migrans (EM) rash and 20 patients with early disseminated (cardiac/neurologic) symptoms or with Lyme arthritis. At initial presentation, 46-48% of the EM patients had IHA reactivity, with titers >/=128, while 42% were positive in the ELISA. Follow-up testing performed on these EM patients, 8-12 days after receiving antibiotic treatment, revealed that Bb antibodies were detected best by the IHA test (83-86% reactive) relative to the ELISA (81% reactive). Bb antibodies were readily detectable on all of the serum samples from the early disseminated and late stage Lyme disease cases in both assay systems. Based on these results and because of its technical and interpretive simplicity, the IHA test should be considered as a useful and convenient alternative for the serological analysis of Bb infections.

Efficacy of an Evernimicin (SCH27899) In Vitro and in an Animal Model of Lyme Disease

ABSTRACT The MICs of evernimicin at which 90% of Borrelia burgdorferi patient isolates were inhibited ranged from 0.1 to 0.5 μg/ml. Evernimicin was as effective as ceftriaxone againstB. burgdorferi in a murine model of experimental Lyme disease. As assessed by culturing the urinary bladders of infected C3H mice, no live Borrelia isolates were recoverable following antibiotic treatment.

Impaired Bactericidal Activity and Host Resistance to Listeria monocytogenes and Borrelia burgdorferi in Rats Administered an Acute Oral Regimen of Ethanol

ABSTRACT A rat model was used to examine how ethanol ingestion may interfere with antimicrobial immunity both in vitro and in vivo. Nonimmune Long-Evans rats were given a short-course treatment orally with excessive amounts of ethanol. Their spleens were removed at the time of sacrifice, and separate spleen cell suspensions were prepared and tested in vitro for their ability to kill two bacterial pathogens, Listeria monocytogenes and Borrelia burgdorferi. After the bacteria were mixed separately with various concentrations of spleen cells, it was found that spleen cells from the ethanol-treated rats killed fewer bacteria than matching pair-fed controls, based on counts of the number of cultured CFU (for Listeria) or based on microscopic examination (for Borrelia). For the in vivo studies, ethanol-treated and control rats were infected intraperitoneally with Listeria, and then, 1 to 3 days later, they were assessed for systemic infection based on the numbers of organisms present in their livers and spleens. Numbers of bacterial CFU for both organs were significantly higher in the group fed ethanol for the first 2 days after listerial challenge. These results support the concept that acute exposure to high levels of ethanol can impair host defense mechanisms, especially those expressed at the cellular level, which could lead to increased susceptibility to certain types of infections.

Failure of Topical Antibiotics to Prevent Disseminated Borrelia burgdorferi Infection Following a Tick Bite in C3H/HeJ Mice

A prior study in mice has shown that the timely application of topical antibiotics to the skin at the tick bite site could eradicate Borrelia burgdorferi infection. That study, however, did not evaluate antibiotic preparations that are considered suitable for use in humans. In this murine study, topical application of 2% erythromycin and 3% tetracycline preparations that are acceptable for use in humans was found to be ineffective in eliminating B. burgdorferi from the tick bite site or in preventing dissemination to other tissues. Reasons for the discrepant findings are discussed.

Developments in immunological technologies leading to improvements in point-of-care diagnostic testing

Rapid and accurate point of care testing is of great concern, especially in terms of detecting infectious disease outbreaks in developing countries having high population burdens. While numerous detection systems are currently available, care must be taken in choosing those that are reliable and have proven acceptable levels of sensitivity and specificity, based on adequate laboratory and pre-clinical trial testing. Two papers in the current issue show significant advances in technology that could bring Point-of-Care Diagnostic Testing closer to reality for cholera and environmental mycobacteria.