MUNICH, GERMANY—Urinary tract infections (UTIs) caused by non-coliform bacteria are significantly more common among renal transplant patients compared with the general population, according to a British study.

The study, which investigators presented at the European Renal Association-European Dialysis and Transplant Association 2010 Congress, also revealed a higher prevalence of antibiotic resistance among coliform bacteria isolated from renal transplant recipients.

Investigators at the Norfolk and Norwich University Hospital in Norfolk, UK, reviewed data from all urine cultures from their institution’s renal transplant recipients and compared the findings to UTI specimens from the general population.

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Of 225 renal transplant patients, 52 had at least one episode of significant bacteriuria (defined as greater than 105 colony forming units). All of these patients were at least three months post-transplant. Their mean age was 51 years.

The researchers identified 157 episodes of significant bacteriuria. All except one involved a single isolate. Coliforms accounts for 76% of episodes, and Pseudomonas, enterococci, and group B streptococci accounted for 12%, 6.4%, and 1.9%, respectively. Coagulase negative staphylococci, group G streptococci, and methicillin-resistant Staphylococcus aureus accounted for 1.9%, 0.6%, and 0.6% of isolates, respectively.

Non-coliform bacteria caused 24% of UTIs transplant recipients compared with only 11% in the general population, although the only single pathogen significantly more frequent was Pseudomonas (12% vs. 1.9%). The researchers pointed out that Pseudomonas may be over-represented because of recurrent infection in a small number of patients.

In addition, compared with the general population, coliform bacteria in the transplant population were significantly more resistant to amoxicillin (69% vs. 50.5%), coamoxiclav (17% VS. 7%), and trimethoprim (43% vs. 27%). Trimethoprim-resistant coliforms were significantly more common in patients during the first year post-transplant than afterwards (50% vs. 14.7%). During the first year post-transplant, the researchers noted, most patients are on cotrimoxazole prophylaxis.

UTI was the only reason for hospital admission in 12 transplant recipients, who had a median hospital stay of 5.5 days. Moreover, UTIs were responsible for deterioration in graft function (defined as an increase in serum creatinine greater than 25%) in seven patients.

“These findings should guide empirical antibiotic choice in the renal transplant population and prompt early detection and treatment of this common condition,” the authors concluded.