members with similar morphological patterns associated with respiratory manifestations in ducks.

AIM

A total of 112 freshly dead ducks aged from 2 to 20 weeks old with a history of respiratory manifestations were investigated for the implication of family members.

MATERIALS AND METHODS

Isolation and identification to the family level were conducted by conventional bacteriological methods, including microscopic examination and biochemical characterization. Identification to the species level was conducted by polymerase chain reaction (PCR) and analytical profile index (API) 20E kits.

RESULTS

Conventional bacteriological isolation and biochemical characterization revealed the infection of 16/112 examined birds with a prevalence rate of 14.3%. PCR confirmed the detection of family conserved genes B and z in 16/16 (100%) isolates. PCR was also used for genus and species identification of the isolated members; the results revealed that 5/16 (31.3%) of isolates were and 2/16 of isolates (12.5%) were . , , and were not detected by PCR. Biotyping by API 20E successfully identified 5/16 (31.3%) isolates that could not be typed by PCR and confirmed their belonging to . Neither the available PCR primer sets nor API 20E succeeded for species identification of 4/16 (25%) isolates. Antibiotic susceptibility profiling of isolates revealed that 16/16 (100%) of isolates demonstrated multidrug resistance (MDR) phenotypes. Moreover, 16/16 (100%) of isolates demonstrated a phenotypic resistance pattern to neomycin.

CONCLUSION

Combined genotypic, phenotypic, biotyping, and virulence characterizations are required for laboratory identification of pathogenic . Moreover, was not the prevailed member implicated in respiratory problems in ducks as , , and unidentified strains were involved with higher prevalence. Chloramphenicol and ampicillin demonstrated the highest effects on the studied . Furthermore, the prevalence of multidrug-resistant isolates signified the demand to implement targeted surveillance in the ducks' production sector, and MDR survey in poultry sectors in Egypt to apply effective control measures.