0px; "> Omphalitis is a major cause of increased first week-chick mortality. Omphalitis, navel-yolk
sac infection, is a hatchery-born disease, and also known as ‘mushy chick disease' or ‘navel
ill'. It is a common disease of chicks and poults, often artificially hatched chicks, causing
high losses in the brooding period, as a bacterium penetrates the porous egg shell. As
incubation conditions are suitable for bacterial growth and incubating eggs as well, various
bacteria, such as E. coli, staphylococci, Proteus, Clostridium fecali and Pseudomonas may
be involved in the yolk sac infection. The present study aimed to determine bacterial
causes of omphalitis through isolation and identification of such pathogens. Therefore,
samples from 216 yolk sacs were collected from chicks with unabsorbed yolk materials that
could even smell putrid. Among those, 196 (90.7%) were positive; 135 (62.5%) harboured
single bacterial strains and 61 (28.2%) had mixed infections. The most prevalent single
bacterial isolates were E. coli (110 isolates) and P. aeruginosa (11 isolates). Meanwhile, the
most predominant mixed bacterial strains were E. coli with Salmonella spp. (16 isolates;
7.4%) and E. coli with P. aeruginosa (13 isolates; 6%). Other mixed infections were found in
low percentages. Most E. coli strains were Congo red-positive and non-haemolytic.
Different E. coli serogroups were serologically identified including O27 (4 isolates; 20%), O157
(3isolates; 15%), O26 (3 isolates; 15%) and one isolate of each of the following; O78, O6, O125,
O44, O15, O115, O25, O168, O112 and O63 (each of 5%). Different Salmonella serogroups were
identified including S. cremieu (2 isolates) and one isolate of each of the following S.
enteritidis, S. blegdam, S. senftenberg, S. kingston and S. emek.Isolated bacteria differed insusceptibility. The adhesion-encoding genes (crl and fimH genes) of E. coli were detected
by cPCR. It has been concluded that chicks with omphalitis harboured different pathogens
and they are considered a source of infection during the successive days of life in broiler
chickens.