Serpil Kahya

Incidence of Salmonella Enteritidis in chicken layer flocks in Turkey: Results by real-time polymerase chain reaction and International Organization for Standardization culture methods

This study presents Salmonella Enteritidis incidence in chicken layer flocks in Turkey determined by real-time PCR (rPCR) and by International Organization for Standardization (ISO) method 6579:2002/Amd 1:2007. A total of 259 samples, composed of 1,036 individual samples each pooled into 4, including 175 cloacal swab, 14 intestine, 35 gizzard swab, and 35 cecal swab samples, belonging to 6 major companies, were collected from 50 layer flocks and tested by rPCR and ISO culture methods. Overall incidence of Salmonella in layer flocks by rPCR and culture was 61.0 and 55.6%, respectively, where 70.1% of these Salmonella isolates were determined as Salmonella Enteritidis. Incidences of Salmonella Enteritidis in culture-positive samples were 65.3% in cloacal swabs, 50.0% in intestines, 73.9% in gizzard swabs, and 87.5% in cecal swabs. The rPCR results were in 100% agreement (100% sensitivity and specificity) with culture results when cecal swabs were selected as the sample type. The relative accuracy of rPCR was 92.4, 91.4, and 84% for intestine, gizzard, and cloacal swab samples, respectively. As a result, by using rPCR and ISO culture, we determined that the Salmonella Enteritidis incidence in layer flocks in Turkey was high and that the use of cecal swab and intestine samples in Salmonella detection would yield reliable results. To reduce this high Salmonella Enteritidis incidence in layer flocks, Salmonella Enteritidis-specific vaccination should be implemented properly in conjunction with a well-designed biosecurity plan, including verifiable corrective actions.

Species Diversity and Pheno‐ and Genotypic Antibiotic Resistance Patterns of Staphylococci Isolated from Retail Ground Meats

The presence and species diversity of staphylococci in 250 ground beef and lamb meat samples obtained from Diyarbakir, Turkey were investigated. The presence of the 16S rRNA gene, mecA, nuc, pvl, and femA was analyzed by multiplex PCR. Pheno- and genotypic antibiotic resistance profiles of 208 staphylococci isolates were established. Of the ground beef and ground lamb samples, 86.4% and 62.4% were positive for staphylococci, respectively. Staphylococcus aureus, S. saprophyticus, S. hominis, S. lentus, S. pasteuri, S. warneri, S. intermedius, and S. vitulinus made up 40.8%, 28.8%, 11%, 3.8%, 3.8%, 2.4%, 2.4%, and 2.4% of isolates, respectively. Of the 85 S. aureus isolates, 40%, 47%, and 5.8% carried femA, mecA, and pvl, respectively, whereas the corresponding rates for the 118 coagulase-negative staphylococci (CoNS) were 0%, 10.1%, and 0%, respectively. We determined from the 208 isolates, the highest antibiotic resistances were to tetracycline and oxytetracycline (85.5%), followed by penicillin (51.4%), novobiocin (45.6%), ampicillin (39.9%), and doxycycline (31.7%), using the Clinical and Laboratory Standards Inst. (CLSI) method. All isolates were sensitive to gentamycin, ofloxacin, and tobramycin, but 2.3% of the S. aureus isolates had resistance to vancomycin. The staphylococci isolates carried tet(K), blaZ, tet(L), tet(W), cat, tet(S), tet(M), ermB, ermA, and ermC antibiotic resistance genes at rates of 59%, 51.7%, 36.9%, 31.8%, 27.2%, 27.2%, 24.4%, 18.1%, 7.9%, and 3.9%, respectively.

Real-time PCR culture and serology for the diagnosis of Mycoplasma gallisepticum in chicken breeder flocks.

This study aimed to compare a real-time PCR (rPCR) test with improved detection limit to serology and culture for the detection of Mycoplasma gallisepticum (MG) infection in chicken breeder flocks. Six hundred and forty-six blood and tracheal swab samples belonging to 31 grandparent chicken breeder flocks were tested by rPCR. The detection limit of rPCR was 0.9 pg microl(-1), with pure MG S6 strain DNA and 100 colony forming units (CFUs) ml(-1), where both pure culture and tracheal swabs were artificially spiked with the same strain. The seropositive flock rate based on both MG RPA and HI were calculated as 48.4% (15/31) and 32.3% (10/31), respectively, while culture- and rPCR-positive flock rates were 16.1% (5/31) and 29.0% (9/31), respectively. On flock-based analysis, culture method detected 5 out of 10 MG seropositive flocks (sensitivity 50%, specificity 100%), whereas rPCR detected 8 out of 10 flocks (sensitivity 80%, specificity 95%). Agreements between serology and culture, and serology and rPCR were 83.9% and 90.3%, respectively. On individual sample-based analysis, culture method detected 26 out of 78 MG seropositive chicken (sensitivity 33%, specificity 100%), whereas rPCR detected 51 out of 78 MG seropositive chickens (sensitivity 65%, specificity 96%). There was 91.9% and 91.4% agreement between serology and culture, and serology and rPCR, respectively. Results of this study indicate that the rPCR with improved in vitro detection limit could detect MG in seropositive chicken flocks. Therefore, we advise the use of rPCR and/or culture for confirmation of serology results obtained from screening MG infection in chicken flocks.