| Author | Design | Setting | Investigation | Outcome | Level of evidence* |
|---|---|---|---|---|---|
| Biljan et al.,9 1993 | Multicentre randomized double-blinded crossover trial, prospective | Outpatient | Comparison of contamination of bow ties v. neckties in obstetric/gynecologic practice, n = 15 physicians | No difference in contamination by third day onward | 1a Jadad scale score 3/5 |
| Lopez et al.,10 2009 | Cross-sectional survey, case-control | Outpatient | Comparison of contamination of neckties v. front shirt pocket, n = 50 physicians (25 surgeons and 25 other physicians) | Higher bacterial counts on neckties than on shirts | 3b NOS score 7/9 |
| Koh et al.,11 2009 | Cross-sectional survey, case-control | Outpatient | Comparison of MRSA on neckties of medical staff (n = 50) v. preclinical medical students (n = 50) | Higher rates of Staphylococcus aureus and MRSA on physicians' neckties than on medical students' neckties | 3b NOS score 7/9 |
| Pisipati et al.,12 2009 | Case-control study, prospective | Outpatient | Comparison of bacterial growth on neckties and pens worn by urological surgeons v. control specimens, n = 4 | Common environmental bacteria found | 3b NOS score 7/9 |
| Weber et al.,13 2012 | Case-control study, prospective | Outpatient | Examined effect of sleeve length and wearing of necktie on rate of transmission of bacteria from physician to simulated patient (mannequin), n = 1 physician in 4 different combinations of attire examining 5 patients per group | Wearing unsecured tie resulted in greater transmission of bacteria; sleeve length did not affect transmission | 3b NOS score 8/9 |
| Dixon,14 2000 | Cross-sectional survey, case series, no control subjects | Inpatient | Examined type of bacteria on neckties of medical staff in intensive care unit, n = 5 | 5/5 coagulase-negative Staphylococcus: 3 S. citreus, 1 "Bacillus species" | 4 |
Note: MRSA = methicillin-resistant Staphylococcus aureus, NOS = Newcastle-Ottawa Scale.
*Assessed with the use of the Oxford Centre for Evidence-Based Medicine Level of Evidence criteria.6 The Jadad scale and the Newcastle-Ottawa Scale were used to assess the quality of evidence.