Volume 29, Number 2—February 2023
Research
Increased Multidrug-Resistant Salmonella enterica I Serotype 4,[5],12:i:- Infections Associated with Pork, United States, 2009–2018
, Allison C. Brown, Erin K. Stokes, Jessica C. Chen, Heather Carleton, Beth Tolar, Preethi Sundararaman, Amy Saupe, Daniel C. Payne, Hazel J. Shah, Jason P. Folster, and Cindy R. Friedman
Table 3
Characteristics of outbreaks caused by multidrug-resistant Salmonella enterica 4,[5],12:i:- compared with other nontyphoidal Salmonella, United States, 2009–2018*
| Outbreak type and transmission mode | Salmonella 4,[5],12:i:-, n = 123 | Other Salmonella, n = 1,829 | PFGE link to MDR clade |
|
|---|---|---|---|---|
| Linked, n = 4 | Not linked, n = 45 | |||
| Multistate outbreak |
13 (10.6) |
284 (15.5) |
3 (4.1) |
10 (22.2) |
| Mode of transmission | ||||
| Foodborne, no single food category† | 52 (42.3) | 792 (43.3) | 25 (33.8) | 26 (57.8) |
| Foodborne, single food category | 23 (18.7) | 414 (22.6) | 17 (23) | 5 (11.1) |
| Animal contact, no single animal type | 6 (4.9) | 15 (0.8) | 4 (5.4) | 2 (4.4) |
| Animal contact, single animal type | 12 (9.8) | 138 (7.5) | 8 (10.8) | 4 (8.9) |
| Person-to-person | 7 (5.7) | 126 (6.9) | 6 (8.1) | 1 (2.2) |
| Environmental | 0 | 15 (0.8) | 0 | 0 |
| Waterborne | 0 | 2 (0.1) | 0 | 0 |
| Unknown transmission |
23 (18.7) |
327 (17.9) |
14 (18.9) |
7 (15.6) |
| Food source, single food category | N = 23 | N = 406 | N = 17 | N = 5 |
| Chicken | 4 (17.4) | 77 (19) | 3 (17.6) | 1 (20) |
| Pork | 13 (56.5) | 47 (11.6) | 11 (64.7) | 1 (20) |
| Turkey | 2 (8.7) | 27 (6.7) | 2 (11.8) | 0 |
| Other food category |
4 (17.4)‡ |
255 (62.8), n = 406 |
1 (5.9), n = 17 |
3 (60) |
| Animal contact, single animal type | N = 12 | N = 138 | N = 8 | N = 4 |
| Live poultry | 3 (25.0)§ | 77 (55.8) | 2 (25.0) | 1 (25) |
| Swine | 5 (41.7) | 0 | 5 (62.5) | 0 |
| Other animal | 4 (33.3)¶ | 61 (44.2) | 1 (12.5) | 3 (75) |
*Values are no. (%) except as indicated. PFGE used as a marker for the MDR clade as defined by core genome multilocus sequence typing in PulseNet. Among sequenced clinical PulseNet isolates collected during 2015–2018 that also had PFGE information, 2,070/3,007 (69%) belonged to a clade associated with ASSuT resistance that contained 275 PFGE patterns; these patterns were identified in 7/937 (0.8%) isolates outside the clade. Excludes 4 outbreaks without PFGE information. ASSuT, ampicillin, streptomycin, sulphamethoxazole, and tetracycline; MDR, multidrug resistant; PFGE, pulsed-field gel electrophoresis. †Includes confirmed 4,[5],12:i:- outbreaks classified as foodborne transmission for which no specific food was reported. ‡Includes dairy (n = 1), nuts or seeds (n = 1), seeded vegetables (n = 1), and sprouts (n = 1). §Linked to contact with chicken (n = 1), turkey (n = 1), or baby chick or duckling (n = 1). ¶Linked to contact with rodents (n = 2), turtles (n = 1), or cattle (n = 1).