From March to July 1998, we collected samples from 250 children and 500 adults by using a single posterior nasal swab, with a sterile cotton swab dipped in saline.
Subsequently, in all patients, pre-biopsy rectal swabs were obtained using a single cotton-tip applicator with agar gel system (Deltalab, Spain).
Finally, we used a single rectal swab followed by conventional culture in chromogenic screening medium to detect persistent intestinal ESBL-E colonization at the time of therapy initiation which may have been too insensitive or resulted in a selection bias favoring the inclusion of patients with high titers of ESBL-E.
For the nose specimen, a single swab is used to sample each nostril.
The fifty nanograms of RNA we used for amplification can routinely be isolated from a single swab (Additional file 1) and the resulting amplified cDNA is sufficient for an array as well as other procedures such as qPCR.
The approach of collecting a single swab from an inoculated bird and the rest from unexposed birds for each pool was used to simulate the diagnostically worst case scenario where only minimal virus is present in the sample.
Pools of varying numbers of swabs were evaluated: a single swab (from an inoculated bird), 5 swabs (1 from an inoculated bird, 4 from unexposed birds), and 11 swabs (1 from an inoculated bird and 10 from unexposed birds).
Similar to AIV, combining 5 or 11 swabs in one vial (1 swab from a chicken exposed to NDV, the remaining swabs from uninfected chickens) was evaluated for virus detection and compared to a single swab.
Swabs (flocked swabs) were collected in 3.5 ml BHI media as either a single swab from an infected bird or as a pool of 5 swabs (4 swabs from uninfected birds and 1 swab from an infected bird) at 1, 2, 3, 4, 7, 10 and 14 days PI.
