Bladder infection, also known as infectious cystitis, is a type of urinary tract infection (UTI) caused by bacterial growth in the urine contained in the bladder. 
Normally, the urine in the bladder is sterile that is, it does not contain any bacteria and in some cases where bacteria is present, it doesn’t cause any symptoms at all. However, in some cases, bacteria present in the bladder can cause cystitis (inflammation of the bladder).
The commonest source of bacteria that causes bladder infection and most urinary tract infections is the stool and the bacteria often implicated is E.coli (Escherichia coli).  Other organisms like Staphylococcal organisms, Proteus, Klebsiella, and Enterococcus can also cause bladder infections.
In rare cases, fungal organisms like Candida cause bladder infections especially in immune-compromised patients and people who have been using indwelling urinary catheters.
Viruses like Adenovirus can also cause bladder infections though those kinds of cases are very rare. It may occur in people who have just had bone marrow transplants or who have weak immune systems.
Common Symptoms of Bladder Infection
The symptoms of bladder infection are the same as the symptoms of lower urinary tract infections. Here are the commonest symptoms related to bladder infection;