Hi Leonard,
Thanks for sharing this case with us. Other colleagues might have some other ideas, but here are some of my and Samantha's initial thoughts/clarifying questions.
-Regarding "the small openings in the body such as upper back and lower back that healed", did they have purulent drainage as well? If so, was any specimen collected for culture and susceptibilities?
-Regarding the wound on the right buttock, with heavy serosanguinous/purulent drainage and odor: Was any investigation performed to evaluate potential skin and soft tissue infection? Any signs or investigation of possible rectocutaneous fistula? (since the "outer wound on the right buttock is increasing in size and tunnels to the left buttocks", and the "pt. has active infection in the rectum for CRE")
-Redness: other possible causes? (e.g. IAD, allergy due to underpad underneath, dermatitis with fungal component, IAD with fungal component/superimposed bacterial, pressure)
-Given history of urinary tract infection and active infection in the rectum for CRE and the description of the wound (purulent drainage, abscess?), skin and soft tissue infection could be a possible etiology of these wounds, as you pointed out - has any investigation been done so far to confirm/rule it out? (other potential causes could be pressure/shear, auto-immune)
Regarding skin and soft tissue infection:
-Given multiple comorbidities, a patient's immunocompromised status can make him/her more prone to skin and soft tissue infections which may not show classic clinical features and laboratory findings because of their attenuated inflammatory response.
-Diagnostic testing should be performed early to identify the causative organism and evaluate the extent of involvement, and antibiotic therapy should be commenced to cover possible pathogens, including atypical organisms that can cause serious infections (e.g., resistant gram-negative bacteria, anaerobes, fungi).[1]
-Inpatient workup for skin and soft tissue infection includes: Labs (CBC, CRP, liver and kidney function), blood culture (due to history and comorbidities), culture of aspirate from wound/abscess (resistant gram-negative bacteria such as CRE, aerobes, anaerobes, fungi), imaging (since no response to initial treatment), tissue biopsy from margin (once debridement is done)
-Management: ID consult, empiric antibiotic therapy followed by culture-specific antibiotics, surgical consultation for potential proper incision and drainage if patient can tolerate (inadequately drained abscesses can lead to the extension of the infection into adjacent tissues and worsening of clinical status), correction of fluid/electrolyte/acid-base imbalance if needed. Regarding empiric therapy: doxycycline was given, but considerations for appropriate empiric therapy for patients at risk of infection with CRE should rely on the patient’s history, risk factors, and prior antibiotic exposure, as well as the local epidemiology of the country and hospital, and most importantly the unit in which the patient is managed [2] If indeed pt. has abscesses/soft tissue infection, it needs to be adequately/comprehensively addressed with culture-guided systemic antibiotics, I&D/debridement, prior to considering wound vac application.[3]
[1]
https://www.aafp.org/afp/2015/0915/p474.html[2]
https://journals.lww.com/co-infectiousdiseases/Abstract/2020/04000/Treatment_of_multidrug_resistant_Gram_negative.8.aspx[3]
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4005496/See also
https://woundreference.com/app/topic?id=negative-pressure-wound-therapy