85M with CAD s/p CABG and MM on daratumumab/dex
Nausea, vomiting, watery diarrhea 7x per day
Alright #IDFellows, can you ID the organism? Hektoen plate below
Photo cred: ASM
https://www.asmscience.org/content/education/imagegallery/image.3276
Guess Salmonella?
🧫Selective hektoen agar
🧫pH indicator dye:agar🟢➡️🟡 if ferment sugar
🟡NOT Salmonella/Shigella
🧫Na thiosulfate for orgs that produce H2S➡️ferric ammonium citrate+H2S gas ➡️⚫️precipitate
🧫Salmonella=🟢+⚫️center (vs Shigella 🟢only)
Salmonella infection, many flavors:
🤮Gastroenteritis (nontyphoidal Salmonella)
🤢Enteric fever (Salmonella typhi/paratyphi)
🩸Bacteremia, endovascular inf
🦵Focal metastatic inf (eg osteomyelitis, abscess)
🙂Asx carriage
💫Let’s focus on nontyphoidal salmonellosis today
🗺️Large global burden
Only 2nd to Norovirus in cases of US gastro➡️accounts for most hospitalizations and deaths though
🦠In US, usually S.enteritidis, S.typhimurium, Salmonella Newport
https://www.cdc.gov/foodborneburden/2011-foodborne-estimates.html
https://wwwnc.cdc.gov/eid/article/17/1/P1-1101_article
Transmission:
⭐️Foodborne: ingestion of poultry, eggs, meat, produce, etc
🚨Current multistate outbreak related to onions https://www.cdc.gov/salmonella/newport-07-20/index.html
⭐️Animal contact: Reptiles high risk (snakes, iguanas, lizards, frogs, turtles) but also in other animals
🔹Incubation: 8-72h
🔹⬆️ingested dose🦠correlates to severity of diarrhea, duration of illness, wt loss
https://pubmed.ncbi.nlm.nih.gov/8119352/
🔹Sometimes called “pea soup” diarrhea, but clinical characteristics can’t reliably differentiate
🔹🌡️/pain/n/v resolves 48-72h➡️Diarrhea 4-10d
🔸Stool cxs can take 48-72h
🔸<5% gastroenteritis cases with nontyphoidal Salm develop bacteremia
🔸But in those with high risk + bacteremia, can give rise to mycotic aneurysms, abscesses, osteomyelitis, IE, endovascular infection
🔸So who’s high risk? More on that later
🚨One of most common w/affinity for arterial wall (along with Staph)
🔹Reported in ~15-25% of cases mycotic aneurysm
🔹Diseased aorta is vulnerable – freq due to bacteremic seeding of atherosclerotic plaque
Here are 2 ex cases:
https://pubmed.ncbi.nlm.nih.gov/27223163/
https://pubmed.ncbi.nlm.nih.gov/31321641/
⭐️Usu self-limited: most immunocompetent 12-50yo dont need tx (risk prolonged carriage>>benefit)
⭐️Let’s look at those at risk and who might warrant tx below.
▪️Tx may improve sx and speed recovery 1-2d in severe illness
https://pubmed.ncbi.nlm.nih.gov/1616214/
https://pubmed.ncbi.nlm.nih.gov/8783703/
Pearls
⭐️Bloody diarrhea doesnt necessarily = severe dz, need for abxs
⭐️Neonate/👶high risk: meningitis=high M&M
⭐️~10% pts >50yo might have arteritis https://pubmed.ncbi.nlm.nih.gov/11152867/
🔹IS pts might have difficulty clearing, prolonged tx (up to wks),need close eval for metastatic dz
🔹Guide tx by suscept. if poss. Can use FQ, 3rd gen ceph, Azithro. Bactrim if can’t tolerate prior
🔹Local resistance has significant geographic variability
🔹Generally tx 3-7d if GI dz but no BSI; ⬆️if BSI, at risk pts
A quick review of Salmonella for your Friday!
Originally tweeted by BIDMC Infectious Diseases Fellowship (@BIDMC_IDFellows) on 14 August, 2020.