Urinary Tract Infections in Patients with Diabetes Mellitus

Abstract

Urinary tract infections (UTI) are second only to respiratory tract infections as problems encountered by practicing physicians. They occur most often in young healthy adult women and are easy treatable in these patients. However, in some patient groups infections occur more often, can have a complicated course, are more difficult to treat and often recur. Many of them have easily recognisable urological abnormalities, but also more subtle conditions as age over 65 years, treatment with immunosuppressive drugs, HIV-infection with a CD4+ count below 200/mm3 and last but not least diabetes mellitus lead to an enhanced susceptibility for UTI. Besides organ complications as retinopathy, nephropathy and neuropathy, infections are common problems in these patients. UTI complications (e.g., bacteremia, renal abscesses, and renal papillary necrosis) occur more often in diabetic patients. We recently have completed a study in 636 non-pregnant women with DM (in- and outpatients and diabetics visiting their GP). The prevalence of asymptomatic bacteriuria was 26% compared to 6% in the control group (p<0,001). The prevalence of asymptomatic bacteriuria in the 378 women with DM type 2 was 29% (compared to 21% in those with DM type I). Therefore, the prevalence of asymptomatic bacteriuria is consistently higher in diabetic women than in non-diabetics. In the study mentioned above risk factors for asymptomatic bacteriuria in all women with DM were retinopathy, macroalbuminuria, a longer duration of the diabetes, a lower body mass index, and a symptomatic UTI in the previous year (p<0,05). Risk factors for asymptomatic bacteriuria in the women with type I diabetes included a longer duration of the diabetes, peripheral neuropathy, and macroalbuminuria. The prevalence of asymptomatic bacteriuria was 29% in women with DM type II. Risk factors in these women included age, macroalbuminuria, a lower body mass index, and a UTI in the previous year. All p-va-lues were adjusted for age. There was no association between the diabetes regulation and the presence of a post-voiding bladder residue and the presence of asymptomatic bacteriuria. We followed the cohort mentioned before for 18 months. Of these 589 women, 115 (20%) developed a symptomatic UTI. Women with DM type II and asymptomatic bacteriuria at baseline had an increased risk of developing UTI, compared to women with DM type II without asymptomatic bacteriuria at baseline (p=0,005). There was no difference in the incidence of a symptomatic UTI between DM type I women with and those without asymptomatic bacteriuria. DM type I women with asymptomatic bacteriuria had tendency to a faster decline in renal function than those without asymptomatic bacteriuria (4,6 versus 1,5%, p=0,02). Studies demonstrate greater susceptibility of diabetic than of nondiabetic animals to urinary tract infection. Suggested mechanisms are: decreased antibacterial activity due to the «sweet urine», defects in neutrophil function, increased adherence to uroepithelial cells. We have shown that bacteria indeed grow better in urine with glucose, however, very high concentrations inhibit growth and in the clinical study no effect of regulation of DM was documented. We also have shown that no difference exist in PMN function between diabetic women with/without and controls. However, Escherichia coli expressing type I fimbriae adhere better to uroepithelial cells of diabetic women.