支原体污染的不同处理方法对比

Presentation at the World Veterinary Poultry Association, Cairo, Egypt, January 2002 p.200

Introduction:

Mycoplasma infection continues to be an important cause of loss in poultry production. Kleven (1990) described the losses due to Mycoplasma gallisepticum (MG). These were a reduction in egg production of 10-20%, an increase in embryo mortality and chick mortality of 5-10% and a reduction in weight gain and feed conversion efficiency of 10-20%. In spite of the availability of vaccines, antimicrobial use continues to be the most economic method (Stipkovits et al, 1993) of controlling these infections, where the diseases are still endemic.

As a result, resistance has developed to a number of antimicrobials and the purpose of this paper is to review the activity of tiamulin and several antimicrobials against a number of common pathogenic poultry mycoplasma, MG, M. synoviae (MS), M. meleagridis (MM) and M. iowae (MI) and compare their resistance development over the last 25 years.

Materials and Methods:

A search of published literature was carried out and these data was combined with our own internal reports. A total of 20 references were compiled. Reports from 1975-1989 and from 1990-2000 were compared. The ranges of minimum inhibitory concentrations (MICs) of various antimicrobials against various mycoplasma species were entered into a database. The maximum and minimum data for each time period were compared for tiamulin, tylosin, oxytetracycline, lincomycin and enrofloxacin.

Results:

From the 20 references and reports, 13 were from before 1990 and seven from 1990 and after. There was information on 241 isolates of MG, 105 of MS, 28 of MM and 111 of MI. The comparative data for the four mycoplasma species are summarized in the tables below.

Table 1. Mycoplasma gallisepticum , MIC ranges (µg/ml) by time period (no. of isolates)

Table 2. Mycoplasma synoviae , MIC ranges (µg/ml) by time period (no. of isolates)

Table 3. Mycoplasma meleagridis , MIC ranges (µg/ml) by time period (no. of isolates)  

Table 4. Mycoplasma iowae , MIC ranges (µg/ml) by time period (no. of isolates)

Conclusions:

MG has shown no resistance development to tiamulin over the last 25 years and all 241 isolates could be considered sensitive. In contrast there is resistance development to tylosin, oxytetracycline, lincomycin and borderline resistance to enrofloxacin and this appears to have increased in the last decade.

MS has shown no increase in resistance to tiamulin and almost all of the 105 isolates would be considered sensitive. In contrast, resistance has developed to tylosin and oxytetracycline. Levels of resistance to lincomycin remain low and all strains could be considered sensitive to enrofloxacin.