Urine infection mcu test. It is curable?

Hello..my 7month old baby got urine infection one time severly with high fvr.treatment is done with antibiotics..one week after treatment again v repeated urine culture and it results infection positive but no fvr so doc told us to wait for 2 weeks and repeat tests.again v repeated blood urea n blood creatin results negative n urine culture again positive.3 times she got urine infection with different organism isolated i e citro bacter, ecoli , gram positive ovalshaped cocci seen but d colony count z reduced from 100000 to 1000cfu/ml.now doc said all z fine but y repeating of infection let us go with mcu test after 10 days.am very much tensed about dat test.what is dat test .what it results?if anything is there it is curable? Pls tell me sir...with these infection n plenty pus cells baby has no fvr very active urine passing 20 times a day no constipation.pls reply me .