engleski

Determination of MIC-s of entrotoxigenic strains of Escherichia coli isolated from weaned pigs.

Large swine farms make the majority of intensive pig breeding in Croatia. Such farms have a high prevalence of respiratory and digestive diseases, so-called breeding diseases, caused by opportunistic bacteria. Treatment of enterotoxigenic Escherichia (E.) coli infections in swine commonly includes the use of broad-spectrum antibiotics. That mostly uncontroled and unnecesary use of antibiotics in most cases leads to bacterial resistance. Minimal inhibition concentration (MIC) values of 40 enterotoxigenic E. coli isolated from pig faeces on 7 big pig farms in Croatia were determined for 10 antimicrobial by an agar dilution method by the use of E-test (AB Biodisk, Sweden). Antimicrobial agent concentrations ranged from 0.002 to 32 &#956; g/ml (enrofloxacin, and thrimethoprim + sulfamethoxazole), from 0.016 to 256 &#956; g/ml (amoxicillin, amoxicillin + clavulanic acid, cefotaxime, gentamicin, and tetracycline), and from 0.064 to 1024 &#956; g/ml (colistin, spectinomycin, and streptomycin). E. coli ATCC 25922 and E. coli ATCC 35218 were used as control strains. Table 1. Detection of minimal inhibitory concentration (&#956; g/mL) in 40 isolates of enterotoxigenic strains of Escherichia coli ¸ Antimicrobial agent MIC50 MIC90 MIC100 Amoxicillin 8.0 > 256 > 256 Amoxicillin + clavulanic acid 3.0 4.0 24 Cefotaxime 0.064 0.064 0.125 Colistin <0.094 <0.125 0.125 Enrofloxacin 0.047 12.0 32.0 Gentamicin 0.50 12.0 32.0 Spectinomycin 32, 0 256.0 1024.0 Tetracycline 64.0 192.0 >256.0 Sulfamethoxazole/trimethoprim 3.0 >32.0 > 32.0 The resistance of enterotoxigenic strains of E. coli strains isolated from large swine agglomerations most probably was due to the obsolete farming technology where economically profitable productivity could hardly be maintained without the systemic use of antibiotics administered in the critical steps of production.

E. coi; pigs; antimicrobial resistance

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