Emerging therapies and diagnostic innovations for multidrug-resistant infections in kidney allograft recipients: Challenges and future directions

Table 1 Key multidrug-resistant phenotypes in kidney transplant recipients - epidemiology, risk factors, and outcomes

Phenotype	Epidemiology	Risk factors	Outcomes
Extended-spectrum beta-lactamase-Enterobacterales	Cause 18%-31% of post-transplant urinary tract infections. Cause 29%-71% of Gram-negative bloodstream infections. Genitourinary tract is the predominant source of bloodstream infection	Diabetes mellitus. Previous antibiotic use. Delayed graft function. Relapsing infection/previous urinary tract infection. Perianal extended-spectrum beta-lactamase carriage (rectal swab). Second kidney transplantation/induction therapy	3 × greater risk of recurrent urinary tract infection. Increased hospitalization needs. Lower 1-year epidermal growth factor receptor. Lower long-term death-censored graft survival. High mortality in bloodstream infection
Carbapenem-resistant Enterobacterales	Incidence in solid organ transplant is 5 × higher than general population. Common species: Klebsiella, Enterobacter. Sites: Urinary tract infection > surgical site infection > catheter-related bloodstream infection	Colonization (21%-38% of colonized patients develop infection). Recipient age > 50 years. Lymphopenia (median 700 cells/mm3). Prior carbapenem use. Colonization by polymyxin-resistant strains	Mortality up to 42%. Higher mortality compared to carbapenem-susceptible infections
Difficult to treat resistant Pseudomonas aeruginosa	Accounts for up to 15% of solid organ transplant bloodstream infections. Up to 43% of isolates in solid organ transplant are multidrug-resistant-Pseudomonas aeruginosa	Prior intensive care unit admission. Nosocomial acquisition. Previous carbapenem therapy	Mortality associated with: Age, urinary catheter, high-risk source, carbapenem resistance, severity of infection. Correct empirical therapy reduces mortality
Carbapenem-resistant Acinetobacter baumannii	Almost exclusively nosocomial. Sites: Soft tissue, urinary tract infection, catheter bloodstream infection, ventilator-associated pneumonia	Hospital/intensive care unit exposure. Mechanical ventilation/invasive devices	Highest mortality among solid organ transplant multidrug-resistant organism infections (> 40%)
Vancomycin-resistant Enterococci	Enterococcus causes 19% of urinary tract infections (mostly Escherichia faecalis). Vancomycin-resistant Enterococci colonization prevalence approximately 14% in kidney transplant recipients. Escherichia faecium has higher vancomycin resistance rates	Perioperative prophylaxis targeting Gram-negatives. Previous vancomycin use. Ureteral stents	Differentiating colonization from infection is vital; colonization does not always lead to infection
Methicillin-resistant Staphylococcus aureus	1.9% of kidney transplant recipients are methicillin-resistant Staphylococcusaureus carriers. Infections occur early post-transplant	Pre-operative colonization. Presence of central venous catheters. Dialysis history	Pre-operative colonization is an independent predictor of renal allograft failure at 5 years
Clostridioides difficile infection	Leading cause of post-transplant diarrhea. Prevalence approximately 2.4%	Antimicrobial exposure (3rd gen cephalosporins, clindamycin, imipenem)	Associated with worse outcomes in kidney transplant recipients