Borrelia burgdorferi vlsE antigenic variation is not mediated by RecA.

RecA is a key protein linking genetic recombination to DNA replication and repair in bacteria. Previous functional characterization of Borrelia burgdorferi RecA indicated that the protein is mainly involved in genetic recombination rather than DNA repair. Genetic recombination may play a role in B. burgdorferi persistence by generation of antigenic variation. We report here the isolation of a recA null mutant in an infectious B. burgdorferi strain. Comparison of the in vitro growth characteristics of the mutant with those of the wild-type strain under various conditions showed no significant differences. While the RecA mutant was moderately more sensitive to UV irradiation and mitomycin C than the wild-type strain, the lack of RecA abolished allelic exchange in the mutant. Absence of RecA did not affect the ability of the mutant to infect mice. However, the RecA mutant was attenuated for joint infection in competitive-infection assays with the wild-type strain. vlsE sequence variation in mice was observed in both wild-type and RecA mutant spirochetes, indicating that the mechanism of antigenic variation is not homologous genetic recombination.

Electrical twitch-obtaining intramuscular stimulation in lower back pain: a pilot study.

OBJECTIVES: To determine if electrical twitch-obtaining intramuscular stimulation (ETOIMS) provides greater myofascial lower back pain relief than muscle stimulation or skin stimulation. DESIGN: In this single-blinded, crossover, pilot trial performed at a university-affiliated outpatient rehabilitation medicine department in Taiwan, 12 acupuncture-naive patients with lower back pain of 3-60 mos duration received one crossover treatment every 2 wks by monopolar needle electrode insertion at bilateral T10-S1 levels to: (1) paraspinal muscles, (2) overlying skin, and (3) paraspinal muscles with ETOIMS applied via the needle electrode at individual treatment sites. A total of 30 manual insertions per side per treatment were performed, with withdrawal after 2 secs. Beginning 1 wk before each trial and continuing until 2 wks after, patients completed a visual analog scale twice daily. In addition, on the day of treatment, patients received a physical examination and completed a visual analog scale both before and after treatment. RESULTS: Significant and immediate reduction in the visual analog scale levels was noted only with ETOIMS. Immediate improvement occurred in one of nine physical tests with muscle stimulation and ETOIMS only. In the 2 wks after treatment, absolute visual analog scale levels for ETOIMS were significantly lower than muscle stimulation and skin stimulation. ETOIMS resulted in a greater percentage of pain relief in the first week after treatment, although it was not statistically significant from muscle stimulation and skin stimulation. CONCLUSIONS: ETOIMS provided significantly greater immediate and sustained myofascial lower back pain relief than muscle stimulation and skin stimulation. Although a greater percentage of pain reduction occurred with ETOIMS, it was not statistically significant.

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.