Jeffrey A. Nelson

Prolonged Suppressive Antibiotic Therapy for Infected Orthopedic Prostheses

Prolonged suppressive antibiotic therapy may be an alternative to removal of infected orthopedic prostheses in some patients. However, the efficacy of prolonged suppressive antibiotics is not well established. We retrospectively reviewed 18 patients with infected orthopedic prostheses who had been treated with prolonged antimicrobial suppression during the last 10 years. Eighteen episodes of infection were identified in these 18 patients. There were nine men and nine women, and the mean age was 66 years (range, 31-83 years). All patients had a functional prosthesis and were treated with surgical debridement, retention of the prosthesis, and administration of intravenous antibiotics for 6-8 weeks, followed by prolonged oral antibiotic suppression. Fifteen of the 18 patients appear to have had a good response and have been able to retain a functional prosthesis. Complications related to antibiotic suppression occurred in 22% but did not necessitate discontinuation of the antibiotic therapy. Prolonged antibiotic suppression is a reasonable alternative to surgery in selected patients with infected orthopedic prostheses.

Molecular characterization of Borrelia burgdorferi sensu lato from Slovenia revealing significant differences between tick and human isolates.

One hundred twenty-nine Slovenian isolates ofBorrelia burgdorferi sensu lato derived from patients (69 strains) orIxodes ricinus ticks (60 strains) were characterized. All of the strains were first- or second-passage isolates obtained in 1992 and 1993 from the same endemic region. The techniques used for the molecular analysis of strains included species-specific polymerase chain reaction (PCR) typing, and pulsed-field gel electrophoretic separation of undigested andMlul-digested genomic DNA. Isolates were identified to the species level by large restriction fragment pattern (LRFP) analysis and the results compared with the species-specific PCR result. Fifty-two patient isolates (75%) were typed asBorrelia afzelii (LRFP MLa1), 6 (9%) asBorrelia garinii (LRFPs MLg1–4), and 11 (16%) asBorrelia burgdorferi sensu stricto. The latter included 9 isolates (13%) with a new LRFP that is not typical ofBorrelia burgdorferi sensu stricto and for which the designation MLx is suggested. In contrast, only 32 of 60 (53%) tick isolates were typed asBorrelia afzelii, while 20 strains (33%) were typed asBorrelia garinii and 8 strains (13%) asBorrelia burgdorferi sensu stricto. Three new LRFPs were found among theBorrelia garinii (MLg5 and 6) andBorrelia burgdorferi sensu stricto (MLb15) tick isolates. Large restriction fragment pattern analysis identified new groups ofBorrelia burgdorferi sensu lato and revealed an apparent difference in the isolation frequency of different species from patients and ticks in the same endemic region.

Infection rate ofIxodes ricinus ticks withBorrelia afzelii, Borrelia garinii, andBorrelia burgdorferi sensu stricto in Slovenia

In spring 1993,Ixodes ricinus ticks were collected from six regions of Slovenia to determine their overall rate of infection withBorrelia burgdorferi sensu lato and to assess the frequency of individual species in these tick populations. Ticks were dissected and midgut tissue inoculated into modified Barbour-Stoenner-Kelly (BSK II) medium.Borrelia isolates were differentiated into separate species using species-specific polymerase chain reaction (PCR) primers and by large restriction fragment pattern (LRFP) analysis. Infected ticks were found in all six regions surveyed. Spirochaetes were isolated from 69 of 363 ticks (19 %): the isolation rate from adult female ticks was 35 % (23/66 ticks cultured), from adult male ticks 22 % (20/91), and from nymphal ticks 13 % (26/206). Determination of the species of 60 isolates revealed that 32 wereBorrelia afzelii (53 %), 20 wereBorrelia garinii (33 %), and 8 wereBorrelia burgdorferi sensu stricto (13 %). In the Ljubljana regionBorrelia afzelii andBorrelia garinii predominated (43 % and 40 %, respectively), whereasBorrelia burgdorferi sensu stricto constituted only 17 % of isolates. In three other regions of the countryBorrelia afzeliiwas isolated exclusively, although the number of isolates investigated was small. This study demonstrates the presence of all three European species ofBorrelia burgdorferi sensu lato within the Slovenian tick population and also within a geographic area of less than 100 m2.

In vitro susceptibility of Borrelia burgdorferi to 11 antimicrobial agents.

The in vitro susceptibility of Borrelia burgdorferi to 11 antimicrobial agents was investigated. The antimicrobial agents evaluated included ceftizoxime, FK037, cefotaxime, dirithromycin, clarithromycin and its metabolite 14-hydroxy-clarithromycin, erythromycin, doxycycline, amoxicillin, ciprofloxacin, and ofloxacin. Isolates of B. burgdorferi tested included two reference strains (B31 and ATCC 53899), six isolates from the midwestern United States, and three from Europe. A broth macrodilution method was used to determine MICs and MBCs. B. burgdorferi was inhibited by < or = 0.5 micrograms of each of the agents except the quinolones per ml. The MBCs for 90% of strains tested of ceftizoxime, FK037, clarithromycin, 14-OH clarithromycin, and dirithromycin (< or = 1.0 microgram of each per ml) were superior to those of amoxicillin (2.0 micrograms/ml) and doxycycline (4.0 micrograms/ml). Further in vivo studies are warranted to determine whether these agents may be efficacious in the treatment of Lyme borreliosis.

Cranial nerve involvement with Lyme borreliosis demonstrated by magnetic resonance imaging

We report a patient with cranial nerve and meningeal symptoms secondary to Lyme borreliosis. MRI using gadolinium contrast material demonstrated this inflammatory process. The patient did not have the parenchymal lesions described in previous reports of patients with CNS Lyme borreliosis.

In vitro activities of lomefloxacin and temafloxacin against pathogens causing diarrhea.

The in vitro activities of temafloxacin (A63004) and lomefloxacin (SC-47111; NY-198) were compared with those of seven other antibiotics against 146 isolates of bacterial enteric pathogens, including Campylobacter jejuni and Campylobacter coli. Ciprofloxacin was the most active drug against the Salmonella, Shigella, Yersinia, and Vibrio spp. tested. Lomefloxacin, temafloxacin, and difloxacin were the most active drugs tested against Campylobacter spp. (MIC for 90% of strains, 0.125 to 0.25 micrograms/ml).

Comparative study of three different dosing regimens of cefotaxime for treatment of gram-negative bacteremia

Thirty-one patients with Gram-negative bacteremia with organisms susceptible to cefotaxime (CTX) (MIC of 1 microgram/ml or less) were randomized to receive 2 g of CTX every 6, 8, or 12 hr. Five-hour susceptibility studies were performed on a bacterial pellet obtained from the patients positive blood culture vial. Thus, patients were enrolled within hours after Gram-negative organisms were demonstrated in their blood cultures. All bacteremias were cleared although two patients had unsatisfactory responses to therapy. Trough serum bactericidal levels were 1:2 or greater in all patients. This study supports that CTX can be used at an 8- or 12-hr intervals in selected patients with Gram-negative bacteremia.