Study of antibiotic resistance of Escherichia coli and Staphylococcus aureus isolated from biomaterial from chickens that died from avian influenza A (H5N1)

Introduction. The aim of the work was to isolate bacterial microflora from chickens that died from influenza and determine their resistance profile to antimicrobial drugs.

Materials and Methods. Pathological material from five dead chickens from private households was delivered to the Laboratory. Detection of the genetic material of the virus was carried out using RT-qPCR according to the protocols recommended by WOAH. The biomaterial was sown on special nutrient media for the isolation of bacterial microflora and determination of pathogenicity for laboratory animals. The sensitivity of the isolated bacterial cultures to 44 antimicrobial drugs was determined by the disk diffusion method according to the EUCAST recommendations with disks with minimal inhibitory concentrations of antimicrobial drugs and Mueller-Hinton agar medium.

Results. In the biomaterial studied from chickens the presence of the highly pathogenic avian influenza pathogen (type A, H5N1) was confirmed. As a result of bacteriological studies, cultures of Escherichia coli and Staphylococcus aureus were isolated and identified from the bone marrow, which were pathogenic for white mice. The results of antibiotic sensitivity studies showed that the isolated culture of Staphylococcus aureus was resistant to antibacterial drugs from the groups of cephalosporins, macrolides, nitrofurans, and fluoroquinolones; the isolated culture of Escherichia coli was resistant to cephalosporins and macrolides.

Discussion. Analysis of the obtained data provided grounds to classify the studied isolates as multidrug-resistant (MDR). Importantly, the anamnesis data does not confirm the use of antimicrobials in households where the death of poultry from highly pathogenic influenza was recorded.

Conclusion. The results obtained indicate the risks of the spread of bacterial pathogens with multiple antibiotic resistance during avian influenza outbreaks, which poses an additional potential threat to personnel.

Acknowledgements: Funded by the EU Next Generation EU through the Recovery and Resilience Plan for Slovakia under the project No. 09I03-03-V01- 00151.