It's the Water
Mark Crislip
Two weeks in a row off. Wonderful. One week a staycation, the other at Mt. Rainier. There are many differences between Portland and the national park. The most notable is masking. Very rare to see anyone without a mask indoors in Portland. Whenever I go to rural counties in Oregon or Washington, mask-wearing plummets. That's also where the cases of COVID are; the rural counties of the Great Pacific NW. Huh. Wonder if there is any relationship?
There are three questions I need to answer for every consult. What is the infection, how to treat the infection, and why is there an infection. Finding the answer to the last question often is the most interesting aspect of the case. The treatment is usually the least interesting. Anyone can look up the correct treatment once the correct diagnosis is made. I have a job in part because most people don't want to bother.
The patient is admitted septic from a necrotic, spreading soft tissue infection. Blood grows Pseudomonas.
It happens.
Nosocomial acquisition, preexisting biliary disease, and recent use of immunosuppressive agents are strong predictive factors for P. aeruginosa bacteremia in cirrhotic patients.
But she had none of the above reasons for Pseudomonas bacteremia. So, from the cellulitis/soft tissue process? Pseudomonas does cause the occasional soft tissue infection in cirrhosis:
73% of culture (16/22) showed growth of gram negative organisms. The organisms were Klebsiella pneumoniae in 6 (27%) patients, Pseudomonas aeruginosa in 6 (27%) and Escherichia coli in 4 (18%) cases. Twenty seven percent (6/22) had Staphylococcus aureus of which two were methicillin-resistant Staphylococcus aureus (MRSA). Out of 45 cellulitis patients without SBP, 10 had culture positivity of which 8 were gram negative organisms (2 Pseudomonas, 4 Klebsiella, 2 E. coli) and 2 were gram positive (Staphylococcus).
The necrotic lesion had been debrided and sent for culture.
Aeromonas.
A well-known cause of necrotic soft tissue infections, the annoying issue is I do not have a concordance of cultures.
What do the two have in common? Water.
And as is so often the cause in the regions around Portland, the patient uses untreated well water for bathing and drinking.
From a total of 20 wells, five were found to contain Aeromonas species with cell number ranging from 26 to 1 609 250 ml−1. In two wells the presence of Aeromonas spp. was not associated to the presence of faecal indicators, i.e. coliforms and faecal coliforms. and
In three families, Pseudomonas aeruginosa was isolated in the well water. In a further three families, Pseudomonas aeruginosa was isolated from bathroom and kitchen components.
It's the water. It used to mean the beer; now it means the infection source.
The Pseudomonas from drinking water and the Aeromonas from bathing.
Best I could do for the why. A course of cefepime made it all better.
I have quite the number of cases in this blog of presumptive well water associated infections.
Rationalization
BMC Infect Dis.2013; 13: 332. doi: 10.1186/1471-2334-13-332 PMCID: PMC3720192 Pseudomonas aeruginosa bacteremia in patients with liver cirrhosis: a comparison with bacteremia caused by Enterobacteriaceae https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3720192/
Ann Gastroenterol. 2014; 27(4): 374–379.PMID: 25331211 Risk factors of cellulitis in cirrhosis and antibiotic prophylaxis in preventing recurrence. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4188936/
Olympia Brewing Company https://en.wikipedia.org/wiki/Olympia_Brewing_Company
The occurrence of Aeromonas spp. in natural mineral water and well water https://www.sciencedirect.com/science/article/abs/pii/S0168160500004104
Pseudomonas aeruginosa folliculitis after shower/bath exposure https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-4362.2000.00931.x