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Ira Schwartz

Publications and source records attributed to Ira Schwartz.

25 records · Page 2Linked to original sources
PubMed2003

Linear and circular plasmid content in Borrelia burgdorferi clinical isolates.

The genome of Borrelia burgdorferi, the etiologic agent of Lyme disease, is composed of a linear chromosome and more than 20 linear and circular plasmids. Typically, plasmid content analysis has been carried out by pulsed-field gel electrophoresis and confirmed by Southern hybridization. However, multiple plasmids of virtually identical sizes (e.g., lp28 and cp32) complicate the interpretation of such data. The present study was undertaken to investigate the complete plasmid complements of B. burgdorferi clinical isolates cultivated from patients from a single region where early Lyme disease is endemic. A total of 21 isolates obtained from the skin biopsy or blood samples of Lyme disease patients were examined for their complete plasmid complements by Southern hybridization and plasmid-specific PCR analysis. All clinical isolates harbored at least six of the nine previously characterized cp32s. Fourteen isolates harbored all B31-like linear plasmids, and seven isolates simultaneously lacked lp56, lp38, and some segments of lp28-1. The distinctive plasmid profile observed in these seven isolates was specific to organisms that had ribosomal spacer type 2 and pulsed-field gel type A, which implies a clonal origin for this genotype. The presence of nearly identical complements of multiple linear and circular plasmids in all of the human isolates suggests that these plasmids may be particularly necessary for infection, adaptation, and/or maintenance in the infected host.

Bacteremia↗
PubMed2002

Disease severity in a murine model of lyme borreliosis is associated with the genotype of the infecting Borrelia burgdorferi sensu stricto strain.

The pathogenicity of Borrelia burgdorferi sensu stricto clinical isolates representing 2 distinct ribosomal DNA spacer restriction fragment-length polymorphism genotypes (RSTs) was assessed in a murine model of Lyme disease. B. burgdorferi was recovered from 71.5% and 26.6% of specimens from mice infected with RST1 and RST3 isolates, respectively (P<.0001). The average ankle diameter and histologic scores for carditis and arthritis were significantly higher after 2 weeks of infection among mice infected with RST1 isolates than among those infected with RST3 isolates (P<.001). These clinical manifestations were associated with larger numbers of spirochetes in target tissues but not with the serum sensitivity of the individual isolates. Thus, the development and severity of disease in genetically identical susceptible hosts is determined mainly by the pathogenic properties of the infecting B. burgdorferi isolate. The RST1 genotype is genetically homogeneous and thus may represent a recently evolved clonal lineage that is highly pathogenic in humans and animals.

Animals↗
PubMed2002

An outbreak of mycobacterial furunculosis associated with footbaths at a nail salon.

BACKGROUND: In September 2000, a physician in northern California described four patients with persistent, culture-negative boils on the lower extremities. The patients had received pedicures at the same nail salon. We identified and investigated an outbreak of Mycobacterium fortuitum furunculosis among customers of this nail salon. METHODS: Patients were defined as salon customers with persistent skin infections below the knee. A case-control study was conducted that included the first 48 patients identified, and 56 unaffected friends and family members who had had a pedicure at the same salon served as controls. Selected M. fortuitum isolates, cultured from patients and the salon environment, were compared by pulsed-field gel electrophoresis. RESULTS: We identified 110 customers of the nail salon who had furunculosis. Cultures from 34 were positive for rapidly growing mycobacteria (32 M. fortuitum and 2 unidentified). Most of the affected patients had more than 1 boil (median, 2; range, 1 to 37). All patients and controls had had whirlpool footbaths. Shaving the legs with a razor before pedicure was a risk factor for infection (70 percent of patients vs. 31 percent of controls; adjusted odds ratio, 4.8; 95 percent confidence interval, 2.1 to 11.1). Cultures from all 10 footbaths at the salon yielded M. fortuitum. The M. fortuitum isolates from three footbaths and 14 patients were indistinguishable by electrophoresis. CONCLUSIONS: We identified a large outbreak of rapidly growing mycobacterial infections among persons who had had footbaths and pedicures at one nail salon. Physicians should suspect this cause in patients with persistent furunculosis after exposure to whirlpool footbaths.

Beauty Culture↗
PubMed2002

Erythromycin resistance in Borrelia burgdorferi.

Susceptibility testing of laboratory strains and clinical isolates of Borrelia burgdorferi indicates that resistance to erythromycin is present in them. Evaluation of the MICs, minimal bactericidal concentrations, and kinetics of bacterial killing of erythromycin suggests that this resistance is increased by preexposure to the antibiotic, is dependent on inoculum size, and may be the result of selection of subpopulations of bacterial cells with increased resistance.

Anti-Bacterial Agents↗
PubMed2002

Quantitative detection of Borrelia burgdorferi in 2-millimeter skin samples of erythema migrans lesions: correlation of results with clinical and laboratory findings.

Variability of disease manifestations has been noted in patients with Lyme disease. A contributing factor to this variation may be the number of spirochetes present in infected patients. We evaluated clinical and laboratory findings for patients with erythema migrans with regard to the number of Borrelia burgdorferi organisms detected by quantitative PCR (qPCR) in 2-mm skin biopsy specimens. B. burgdorferi was detected in 80% (40 of 50) of the specimens tested; the mean number of spirochetes in these specimens ranged over 3 orders of magnitude (10 to 11,000 spirochetes per 2-mm biopsy specimen). Larger numbers of spirochetes were significantly associated with a shorter duration of the erythema migrans skin lesion (P = 0.020), smaller skin lesions (P = 0.020), and infection with a specific genotype of B. burgdorferi (P = 0.008) but not with the number or severity of symptoms. Skin culture positivity was significantly associated with skin lesions containing larger numbers of spirochetes (P = 0.019).

Adult↗