Helicobacter cinaedi appears to cause recurrent cellulitis with fever and bacteremia in immunocompromised hosts. Blood cultures from immunocompromised patients with these symptoms may need special handling to isolate H. cinaedi.

The E Test (AB Biodisk, Solna, Sweden) is a new method for performing antimicrobial susceptibility tests. It consists of an impervious carrier (5- by 50-mm strip) with a predefined antimicrobic gradient which is placed on an inoculated agar plate and processed like a disk diffusion test. Results are generated directly as MICs from a continuous concentration gradient covering 15 twofold dilutions, and MICs are read where the edge of the inhibition zone intersects the strip. We compared the E Test with disk diffusion, broth microdilution, and agar dilution tests by using a challenge set of 195 gram-positive and gram-negative bacteria for 14 antimicrobial agents. Also, disk diffusion, broth microdilution, and agar dilution tests were compared with each other. All test method comparisons gave greater than 94% agreement for the category of susceptibility. The E Test category agreement with disk diffusion and broth microdilution was 95.1%, and with agar dilution it was 95.2%. The E Test results were as reliable as the results obtained by the standard antimicrobial susceptibility testing methods.

We evaluated the clinical characteristics of patients with Francisella philomiragia (formerly Yersinia philomiragia) isolated from normally sterile sites. Isolates from 14 patients were received by the Centers for Disease Control between 1975 and 1987: 9 were from blood; 2 from lung biopsies; and 1 each from pleural, peritoneal, and cerebrospinal fluid. Underlying problems included chronic granulomatous disease in 5 patients, near-drowning in 5, and a myeloproliferative disease in 2. All 13 patients for whom records were available had a febrile syndrome compatible with bacterial infection. Pneumonia and fever-bacteremia were the commonest clinical syndromes reported. In 7 cases, F. philomiragia was the only sterile-site isolate, and the clinical syndrome did not resolve without appropriate antibiotics. Familiarity with this organism is important because of its ability to cause serious disease in chronic granulomatous disease and near-drowning patients. Further study may yield new insights into pathogenic and host defense mechanisms.

Seventy-eight aerotolerant Campylobacter isolates were characterized phenotypically and by DNA hybridization (hydroxyapatite method at 50 and 65 degrees C). Two DNA relatedness groups were found. (i) Sixty-four strains belonged to aerotolerant Campylobacter DNA hybridization group 2. These organisms were isolated from humans, primarily with diarrheal illness, and animals on several continents. Strains were aerotolerant at 30 and 36 degrees C and catalase negative or weakly catalase positive, grew in media containing glycine and on MacConkey agar, were susceptible to nalidixic acid, and were resistant to cephalothin. The name Campylobacter butzleri sp. nov. is proposed for this group. (ii) DNA hybridization group 1 consisted of the type strain of Campylobacter cryaerophila and 13 additional strains isolated from 10 animals outside the United States and from three humans within the United States. This group was genetically diverse; five strains were closely related to the type strain of C. cryaerophila (DNA hybridization group 1A), and eight strains were more closely related to one another (DNA hybridization group 1B). Strains in DNA hybridization group 1B were phenotypically diverse, with two of eight strains resembling C. cryaerophila. The seven strains from DNA hybridization groups 1A and 1B which resembled C. cryaerophila and the C. cryaerophila type strain were aerotolerant only at 30 degrees C and catalase positive, did not grow in glycine or on MacConkey agar, were generally susceptible to nalidixic acid, and were resistant to cephalothin. The remaining six strains of DNA hybridization group 1B phenotypically resembled C. butzleri; however, they were generally catalase positive and susceptible to nalidixic acid and cephalothin. DNA hybridization group 1B is not designated as a separate species at this time since it cannot, with certainty, be separated genetically from C. cryaerophila or phenotypically from C. butzleri.

A modified Mueller-Hinton broth was developed to perform antimicrobial susceptibility tests on Francisella tularensis. Adequate growth of the organism was obtained within 24 h of inoculation, and MICs could be read at that time. We tested 15 selected strains of F. tularensis and five reference quality control strains in this medium with 36 antimicrobial agents. The MICs of the aminoglycosides and tetracycline increased 1 to 3 dilutions in this medium compared with those in the usual medium, but the other antimicrobial agents were not consistently affected by the medium. Even though the medium caused an increase in MICs, the aminoglycosides and tetracyclines remained very active in vitro against F. tularensis. Other antimicrobial agents effective in vitro were chloramphenicol, erythromycin, ceftazidime, moxalactam, cefotaxime, ceftriaxone, and Sch 29482 (a cephalosporin).