A chemical formula that indicates the simplest numerical ratio of the elements within a molecule, without demonstrating the molecule's chemical bonds or structure. For example, the empirical formula for water is H2O. Synonym: molecular formula.
Pelvic inflammatory disease (PID) is an infection caused by bacteria. When bacteria from the vagina or cervix travel to your womb, fallopian tubes, or ovaries they can cause an infection. Most of the time, PID is caused by bacteria from chlamydia and gonorrhea. These are sexually transmitted infections (STIs). Having unprotected sex with someone who has an STI can cause PID.
Kidney infection is typically caused by a bacterial infection of the urinary tract. The bacteria gain access to the urinary tract from outside through the urethra (the drainage tube for urine from the bladder). Many kinds of bacteria can cause kidney infection, but the most common cause is Escherichia coli (E. coli). Other kinds of bacteria that can cause kidney infection include Klebsiella, Enterobacter, Pseudomonas, Citrobacter, certain types of Staphylococcus, and Proteus mirabilis.