The in vitro activities of six antimicrobial agents were tested against 162 mycoplasma strains of eight species isolated from poultry and livestock at different geographic sites. Tiamulin was most active (MICs at which 90% of the isolates were inhibited [MIC90s], 0.025 to 0.25 microg/ml); enrofloxacin and danofloxacin had near equivalent activities (MIC90s, 0.05 to 1.0 microg/ml), but were much more active than flumequine (MIC90s, 1 to 50 microg/ml). The MIC90s of tylosin and oxytetracycline were 0.25 to > 100 microg/ml and 0.25 to 100 microg/ml, respectively.

BOVINE respiratory disease (BRD) in calves is a multifactorial disease complex involving interactions between a wide range of pathogens, immune status and environmental stresses. The most common non-viral pathogens involved include Mannheimia (Pasteurella) haemolytica, Pasteurella multocida, Histophilus somni (Haemophilus somnus) and Mycoplasma bovis (Bryson 2000, Donachie 2000, Nicholas and Ayling 2003. To ensure effective treatment of disease, veterinarians and researchers regularly need to determine the presence and antimicrobial sensitivity of pathogenic bacteria during outbreaks of BRD on farms and in clinical studies. Ideally, the technique should be quick and simple, and involve minimal stress for the calf. The ability to sample entire groups of animals and monitor infection status over time is also valuable and would be facilitated by the use of a simple nasopharyngeal swab method compared with the more difficult and hazardous procedures such as transtracheal aspiration or bronchoalveolar washings. This short communication describes the use of a deep nasopharyngeal swab technique to predict the presence of specific pathogenic species in the lower respiratory tract. Isolates were tested to determine their sensitivity to tulathromycin, a member of the newly developed triamilide subclass of macrolide derivatives (Letavic and others 2002). The study was conducted under veterinary supervision and in accordance with good clinical practice guidelines (Anon 2000), and the husbandry of all animals was in accordance with local animal welfare requirements and legislation.Thirty-seven beef calves, approximately four to six months of age, were group-housed on straw in an open-fronted barn in France, when a natural outbreak of BRD occurred. The criteria for enrolment in the study were those usually applied for the initiation of antimicrobial therapy, that is, the presence of clinical signs of BRD as defined by an elevated rectal temperature (≥40°C), together with abnormal respiratory signs (increased rate and/or abnormal character) and a depressed demeanour. Within the group, 20 animals met the criteria and were enrolled, which ensured a similar severity of disease among all the enrolled animals. The remaining calves were not enrolled but remained on the premises and were treated later for BRD with appropriate medication, if required, including antimicrobials.Nasopharyngeal samples were collected from each animal enrolled in the study, using sterile equine uterine culture swabs, 76 cm long, guarded by an external sheath and with the swab tip protected by a gelatine plug (Equi-Vet; Krusse). The animal's head was restrained by an assistant and the external nares were wiped clean of discharges. The distance between the nostril and the medial canthus of the eye was estimated and marked by the operator gripping the swab sheath at this point. The guarded, sheathed swab was then inserted into the nasal cavity as far as permitted by the position of the hand holding the swab. The tip of the swab was extruded beyond the sheath a...

Lower respiratory tract disease developed in a group of racehorses in training between two and six years of age. Disease was observed in 22 of 25 horses for which full records were available. Seroconversion to Mycoplasma felis was demonstrated by indirect haemagglutination assay in 19 of 22 paired sera and high titres (> or = 64) were found in convalescent sera from the three remaining horses. Evidence of respiratory viral infection was confined to seroconversions to equine herpesvirus-4 in two of the horses. Tracheal wash samples, taken from four horses with visibly increased tracheal mucopus, contained more than 10(4) colony forming units/ml M felis and high proportions of neutrophils. This is the first description of an outbreak of lower respiratory tract disease in horses in training associated with M felis infection.

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PLATE XT-MYCOPLASMAS produce very small colonies on solid media. This may be due to their urease activity, leading to local accumulation of ammonia (Manchee and Taylor-Robinson, 1969); these authors increased the size of colonies by adding to the medium a new hydrogenion buffer, N-2-hydroxy-ethylpiperazine-N-~ethanesulphonic acid (HEPES). This observation suggested to us that other buffers might have a similar effect, and the present paper describes the development of a solid medium containing phosphates for the growth and identification of T-mycoplasmas. The latter have recently been placed in the new genus Ureaplasmu, the specific epithet for human isolates being urealyticum (Shepard et al., 1974). MATEFUALS AND METHODSOrganisms. All the mycoplasmas examined were human genital strains. T-mycoplasma, strain T,, had been subcultured 11 times, and strains TI, T2, T7 and Tlo only five times after isolation. Stock suspensions were stored, as broth cultures, at -7O"C, in small amounts. Mycoplusma hominis, strain 164, was isolated at Dulwich Hospital and passaged three times on conventional mycoplasma medium before storage at -70°C.Media. The basic medium used consisted of 1.2% Oxoid Agar, no. 3, in distilled water, 60 ml; horse serum (Wellcome no. 3), 20 ml; 25 % extract of baker's yeast containing 18 % Tryptone Soya Broth (Oxoid), 10 ml; 10% solution of urea (BDH Analar), 1 ml; 0.4% phenol red, 0 5 ml; 1 % thallium acetate, 1 ml; and penicillin (10, OOO units per ml), 2 ml.The pH was suitably adjusted, as described in the text, with 1*5~-solutions of KH2PO4, Na2HP04, NaH2P04.2H20 (all BDH Analar) or K2HP04 (BDH Lab. reagent), or, in the case of non-buffered batches of media, with 1~-or O~N-HCI (BDH Analar) or O.lN-NaOH (BDH Analar). The fmal volume of medium was made up to 100 ml with distilled water. After inoculation, the plates were incubated at 3637°C in an atmosphere of 95 % nitrogen and 5 % C02.The fluid medium used for the original isolation of the T-mycoplasmas had the same composition as the solid medium but without agar and phosphate buffers, and the pH was adjusted to 6.5 with N-HCl. Lincomycin, 12-5 pg per ml, was added to suppress the growth of M. hominis (Braun et al., 1970).Evaluation of colonial growth. Stock suspensions of T-mycoplasmas, suitably diluted to produce about 100 colonies per plate, were inoculated, in 0.05 ml volumes, across the agar surface. Counts were done after 3-days' incubation, at 25-fold magnification for colonies on phosphate-buffered medium and 60-fold magnification for colonies on medium without buffer. Colony diameters were measured with a graticule and expressed as the average of ten colonies per plate.Removal of soluble constituentsfrom agar plates. The properties of the precipitate formed in T-mycoplasma colonies were examined after soluble medium components had been removed by washing. The agar gel was taken out of the petri dish, placed in a nylon net