450
U. ULLMANN
Chang and Ogg (1970) discovered a temperate bacteriophage designated VPF-11 that was capable of transducing the Streptomycin-resistance
characteristic to strains of C.. fetus. T h e transduction is possible between
subsp. fetus and subsp. intestinalis strains and has a frequency of 4-5 x 10-6
transduction per infecting phage particle. The authors (Chang and Ogg,
1971) could also demonstrate the transduction of the glycine tolerance from
a glycine-resistant donor to the glycine-sensitive recipient strain. Therefore,
use of the glycine characteristic seems to be questionable for differentiation
of subspecies fetus and subspecies intestinalis.
VIII. TESTING OF C . FETUS AGAINST ANTIBIOTICS
The disc methods are standardised for testing of rapid growing pathogens only. Micro-organisms that are fastidious in their nutritional requirnients and need an anaerobic/microaerophilic atmosphere or increased
concentrations of COz for growth show a poor growth on Mueller-Hinton
agar. Strain to strain variation in the growth rate is often observed.
Following the recommendations of the National Committee for Clinical
Laboratory Standards (1975), micro-organisms like C . fetus should not be
tested by disc diffusion methods since the results cannot be properly
interpreted. T o use diffusion methods in the laboratory for testing of
Campylobacter the Mueller-Hinton agar (Oxoid, BBL) must be supplemented with 10% defibrinated, cooked sheep or ox blood without antimicrobial activity.
The agar dilution method using the medium described above under
appropriate incubation conditions is the method of choice for susceptibility
testing of C . fetus.
Brown and Sautter (1977) describe detailed susceptibility testing of C.
fetus subsp. intestinalis using the microtube dilution technique and MuellerHinton broth. This method can be effective in many isolates, but our experience shows that a number of strains, especially subspecies fetus do not grow
in Mueller-Hinton broth. Most strains are resistant to Penicillin G,
Cefalotin (including Cefoxitin), and susceptible to Clindamycin, Erythromycin, Ticarcillin, and Gentamicin (Butzler et al., 1974; Chow et al.,
1977; Ullmann, 1978). Differences in sensitivity between the subspecies
have not yet been noted.
IX. EPIDEMIOLOGY OF C. FETUS
T h e epidemiology of C. fetus in animals is generally understood. I n
man, however, there are epidemiological problems. In the literature, about
150 human infections are documented. Many isolations are not published
U. ULLMANN
Chang and Ogg (1970) discovered a temperate bacteriophage designated VPF-11 that was capable of transducing the Streptomycin-resistance
characteristic to strains of C.. fetus. T h e transduction is possible between
subsp. fetus and subsp. intestinalis strains and has a frequency of 4-5 x 10-6
transduction per infecting phage particle. The authors (Chang and Ogg,
1971) could also demonstrate the transduction of the glycine tolerance from
a glycine-resistant donor to the glycine-sensitive recipient strain. Therefore,
use of the glycine characteristic seems to be questionable for differentiation
of subspecies fetus and subspecies intestinalis.
VIII. TESTING OF C . FETUS AGAINST ANTIBIOTICS
The disc methods are standardised for testing of rapid growing pathogens only. Micro-organisms that are fastidious in their nutritional requirnients and need an anaerobic/microaerophilic atmosphere or increased
concentrations of COz for growth show a poor growth on Mueller-Hinton
agar. Strain to strain variation in the growth rate is often observed.
Following the recommendations of the National Committee for Clinical
Laboratory Standards (1975), micro-organisms like C . fetus should not be
tested by disc diffusion methods since the results cannot be properly
interpreted. T o use diffusion methods in the laboratory for testing of
Campylobacter the Mueller-Hinton agar (Oxoid, BBL) must be supplemented with 10% defibrinated, cooked sheep or ox blood without antimicrobial activity.
The agar dilution method using the medium described above under
appropriate incubation conditions is the method of choice for susceptibility
testing of C . fetus.
Brown and Sautter (1977) describe detailed susceptibility testing of C.
fetus subsp. intestinalis using the microtube dilution technique and MuellerHinton broth. This method can be effective in many isolates, but our experience shows that a number of strains, especially subspecies fetus do not grow
in Mueller-Hinton broth. Most strains are resistant to Penicillin G,
Cefalotin (including Cefoxitin), and susceptible to Clindamycin, Erythromycin, Ticarcillin, and Gentamicin (Butzler et al., 1974; Chow et al.,
1977; Ullmann, 1978). Differences in sensitivity between the subspecies
have not yet been noted.
IX. EPIDEMIOLOGY OF C. FETUS
T h e epidemiology of C. fetus in animals is generally understood. I n
man, however, there are epidemiological problems. In the literature, about
150 human infections are documented. Many isolations are not published