Treatment of UTI in an Elderly Male

Mark E. Williams, MD

Disclosures

October 09, 2002

Question

What is the best approach to management of a urinary tract infection (UTI) in an 83-year-old man with symptoms of urinary frequency and urgency without dysuria? He also has chronic obstructive pulmonary disease (COPD), predominantly chronic bronchitis, and isolated systolic hypertension. His serum creatinine is normal. The urinalysis showed pyuria. After taking ciprofloxacin 250 mg twice a day for 7 days, this decreased from 35-45 leukocytes/mm3 to 15-20.

Response from Mark E. Williams, MD

Urinary tract infection, usually asymptomatic, is the most common bacterial infection in elderly people. In the general elderly population older than 80 years of age, UTI occurs in as many as 50% of women and 20% of men. The prevalence is lower in people living at home and is highest in seniors who are hospitalized or living in long-term-care facilities. Several recent reviews of this topic are available.[1,2,3]

Two important differences exist in elderly patients with respect to pathogenesis of UTI as compared with infections typically seen in younger women: (1) the presence of bacterial biofilms on the bladder wall and (2) residual urine, which forms the nutritional substrate to support continued bacterial growth. In addition, antibacterial prostatic secretions decrease in men as they age. UTIs most commonly occur in older men with prostatic disease, bladder outlet obstruction, or after urinary tract instrumentation.

Pyuria, the presence of leukocytes in the urine, demonstrates a host's response to infection. A count of 10 leukocytes/mm3 or greater is considered abnormal. Microscopic examination of Gram-stained midstream urine is a practical way to provide information on bacterial presence. Obtaining a urine culture with microbial sensitivities is very important as well.

In men, unlike in women, a urine culture growing more than 1000 colony-forming units (CFU) of a pathogen per mL of urine is indicative of a UTI. Elderly men with lower tract symptoms should be treated for 7-14 days. Fluoroquinolones are probably the preferred empiric therapy because the resistance rates to amoxicillin and to trimethoprim-sulfamethoxazole (TMP/SMX) in community-acquired Escherichia coli infection is approaching 20%. Consensus regarding the need for a urologic work-up in men with UTIs is lacking.

Escherichia coli is the organism that is the most frequent cause of UTI in elderly women. For men, Proteus mirabilis is the most frequently isolated organism in the long-term-care setting. Other frequently isolated Gram-negative bacilli are Klebsiella pneumoniae and multidrug-resistant Gram-negative bacilli, including Enterobacter, Citrobacter, Pseudomonas aeruginosa, and Providencia. Among Gram-positive organisms, coagulase-negative Staphylococci, Enterococci, and Group B Streptococci are most frequently isolated.

Given these issues, a reasonable course for the patient under discussion would be to treat for a full 14 days with a fluoroquinolone. If the symptoms did not resolve, then obtain a urine culture (after at least 48 hours off of antibiotics) and await the results. Adjust the antibiotic coverage based on results of the culture and sensitivities. If the culture happens to show Staphylococcus aureus, then a search for occult staph infection (such as bacterial endocarditis) is warranted. Renal ultrasound to rule out unilateral obstruction is also sometimes useful. Urologic evaluation to relieve possible bladder outlet obstruction (determined by checking the postvoid residual urine) is another diagnostic option for chronic UTI.

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