I have a bladder infection. It is possible to transfer the infection to my sex partner?

D.R.

Cystitis, or an infection of the bladder (the organ in the lower abdomen that holds urine until you are ready to urinate), is one of the most common reasons people see a physician. Patients typically complain of a burning sensation during urination, because the infection also usually involves the urethra, the tube that carries urine from the bladder to the outside. Other symptoms include pain and the need to urinate frequently. A fever, which does not occur in cystitis, suggests the patient may have pyelonephritis, an infection of the kidneys (the organs that rid the body of wastes and make urine). A bladder infection can easily spread to the kidneys through the ureters, two tubes that connect the kidneys to the bladder.

In almost all cases, cystitis occurs when bacteria enter the bladder through the urethra. Women are more likely than men to develop cystitis, mainly because the urethra is shorter in women. E. coli, a bacterium that is normally found in stool, is by far the most common cause of cystitis. After the bacteria colonize the area around the urethra, they make their way into the bladder, causing the typical symptoms of cystitis. Some women who are predisposed to developing frequent urinary tract infections (UTIs) can have multiple recurrences in a single year, while other women go through life without ever having an infection. Part of this predisposition involves genes that affect the way the body handles bacteria in the area around the urethra.

Some women develop UTIs after sexual intercourse. In fact, intercourse is one of the biggest risk factors for UTIs in women, presumably due to mechanical stresses to the area that cause small areas of trauma (physical injury) and aid the movement of bacteria into the bladder. Use of a spermicide (the sperm-killing chemical in contraceptive creams or jellies) also increases the risk of cystitis, especially when used in combination with a diaphragm. However, sexual intercourse generally does not cause a bladder infection in the male partner. Although there are some reports that men having intercourse with infected women have a slightly higher risk of developing UTIs, the overall risk appears to be quite low. In fact, it is not really necessary to refrain from intercourse during a bout of cystitis.

One important note about the sexual implications of UTIs is the following. To confirm the diagnosis of cystitis, the urine is tested for signs of inflammation and for the presence of bacteria. However, most physicians do not bother testing every patient with a classic case of cystitis. It is not cost-effective to do so, when most cases are certainly simple bladder infections. However, in some cases, what appears to be a UTI may be an infection of the cervix (the neck of the womb) or urethra due to gonorrhea, chlamydia or other sexually transmitted organisms. In these cases, the usual antibiotics used to treat UTIs, such as trimethoprim-sulfamethoxazole (Bactrim), may not be effective, and the sexual partner could become infected.