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Borrelia isolates associated with Lyme borreliosis were previously divided into 3 genospecies, B. burgdorferi sensu stricto, B. garinii and group VS461, on the basis of DNA homology. B. burgdorferi sensu stricto and B. garinii were identified by monoclonal antibodies (MAbs), H3TS and D6 respectively, but no MAbs were available to identify group VS461. Two MAbs were produced, I 17.3 and J 8.3 which reacted with OspB and OspA proteins, respectively, of strains belonging to group VS461, which should be named B. afzelii sp. nov. 24 strains were assigned to B. afzelii sp. nov., 11 of them being isolated from skin lesions, 6 from acrodermatitis chronica atrophicans (ACA) and 5 from erythema chronicum migrans (ECM). Although quite unknown in the USA, ACA has frequently been reported in northern Europe where B. afzelii sp. nov. is commonly isolated. This study documents the involvement of B. afzelii sp. nov. as a specific aetiological agent of ACA.

Pseudomonas cepacia, considered a phytopathogenic organism for many years, has been shown recently to be widely distributed geographically. The hospital environment has become an important source of this organism but the resistance of Ps. cepacia to most antibiotics has made the treatment of infections a problem. One hundred per cent of the strains tested have proved to be sensitive to the sulphonamides and to novobiocin, 93.0% to the combination of trimethoprim and sulfamethoxazole (co-trimoxazole); 85.2% to minocycline; 77.8% to chloramphenicol and dibekacin and 44.4% to nalidixic acid. One hundred per cent of the strains exhibit resistance to ampicillin, cephalothin, cefamandole, cefoxitin, colistin, cefuroxime, tetracycline and cefazolin; 88.9% to amikacin, tobramycin and sisomycin; 85.2% to carbenicillin. The new beta-lactams, apalcillin, ceftazidime, N-formimidoyl-thienamycin, piperacillin, cefotaxime and azlocillin proved to be the most potent of the molecules tested, inhibiting 90% of the strains, at concentrations of 4, 8, 8, 8, 32 and 16 mg/l and 100% of the strains at 8, 16, 16, 32, 32 and 64 mg/l, respectively. In contrast to the usual sensitivity patterns of Pseudomonas spp, Ps. cepacia has been shown to be resistant to colistin, cefsulodin and the aminoglycosides. However, unlike Ps. aeruginosa, Ps. cepacia has been shown, by the dilution method, to be sensitive to co-trimoxazole, 92.3% of the strains being inhibited by 16 mg/l.

The in vitro sensitivity of 300 nosocomial strains of Pseudomonas aeruginosa to ceftazidime was compared with their sensitivities to eleven other beta-lactam antibiotics. Concentrations of 2 mg/l of ceftazidime were sufficient to inhibit all of the strains tested including the carbenicillin-resistant ones. Ceftazidime shows considerably greater activity against Ps. aeruginosa than the other beta-lactam antibiotics.