Aim: Retrospective evaluation of urine cultures of kidney transplant patients with urine growth between January 2016 and January 2024 in our center in terms of pathogen and antibiotic resistance against the most common pathogen.
Method: We performed a retrospective analysis of 961 urine cultures with growth data obtained by transplant patients.
Results: Escherichia (E.) Coli (54%) was the most common pathogen grown in 961 urine cultures. The following pathogens were Klebsiella Pneumoniae (23%), Enterococcus Faecalis (6%), Pseudomonas Aeruginosa (3%), and Proteus Mirabilis (3%) (Fig. 1-(a)).
Other pathogens grown are listed according to their frequency of occurrence; Ureaplasma Urealyticum, Klebsiella Oxytoca, Serratia Marcescens, Mycoplasma Hominis, Proteus Vulgaris, Enterobacter Cloacae, Morganella Morganii, Klebsiella Variicola, Enterococcus Faecium, Staphylococcus Epidermidis, Citrobacter Koseri, Enterococcus Aerogenes, Candida Albicans, Citrobacter Freundii, Candida Kefyr, Corynebacterium Amycolatum, Streptococcus Agalactiae, Corynebacterium Spp., Acinetobacter Baumannii, Staphylococcus Haemolyticus, Staphylococcus Lugdunensis, Staphylococcus Aureus, Staphylococcus Capitis, Staphylococcus Saprophyticus, Kluyvera Spp., Hafnia Alvei, Raoultella Ornithinolytica, and Serratia Odorifera.
When we look at the antibiotic resistance we observed against E. Coli, the most common pathogen, we observed antibiotic resistance; Ampicillin 88%, Trimethoprim-Sulfamethoxazole 82%, Ciprofloxacin 64%, Cefuroxime (oral) 44%, Amoxicillin-Clavulanic Acid 41%, Ceftriaxone 40%, Cefepime 30%, Gentamicin 26%, Cefuroxime (IV) 19%, Piperacillin-Tazobactam 18%, Ampicillin-Sulbactam 17%, Nitrofurantoin 16%, Amikacin 15%, Fosfomycin 4%, Cefixime 3%, Ceftazidime 2%, Cefoxitin 1%, and Ertapenem 1% (Fig 1-(b)).

Discussion: Urinary tract infection is the most common bacterial infection in kidney transplant recipients, occurring in 29-60% with a prevalence of 23-75%. Further, the coexistence of pyelonephritis and bloodstream infections is common. Post-transplant urinary tract infections may lead to increased mortality and at least acute deterioration of renal function and possibly long-term allograft damage.  It is important to keep urinary tract infections in mind in these patients, to search for them, and to eradicate these pathogens with appropriate antimicrobial therapy. Although the problem of infection in these patients has been solved with the development of surgical techniques, regulation of immunosuppressive therapies, and prophylactic antibiotic use, it persists. E. Coli remains the most common organism causing urinary tract infections, which is quantitatively shown in our study.
Conclusion: We believe that it would be appropriate to consider the information provided in our study as a guideline when (1) empirical drug use is in question and (2) there is growth in urine cultures of organ transplant patients.