Exp. No.4(b) Processing of clinical samples: Urine

 

Urine 

Introduction

The presence of bacteria in urine is called bacteriuria. Significant bacteriuria is usually accompanied by pyuria (pus cells in urine). Infection of the bladder is called cystitis, and infection of kidney is called pyelonephritis. Escherichia coli is the commonest cause of urinary tract infection. Possible Pathogens are Staphylococcus saprophyticus, Pseudomonas aeruginosa, Escherichia coli, Proteus sp. Klebsiella spp., Hemolytic Streptococcus, Enterococcus Sp.

Aim

To analyze the etiology of urinary tract infection.

Materials and Methods

Blood agar, MacConkey agar, Cetrimide agar, CLED agar, SS agar, KF streptococcus agar, Nutrient agar.

Procedure

            Clean, void mid-stream samples of urine are collected. It is in sterile, dry, wide necked, leak proof container, about 20mlof sample should be collected. If immediate delivery to the laboratory is not possible, the urine should be refrigerated at 4°C.The delivery of more than 1 hour is anticipated, boric acid should be added to the urine. Specimen containing boric acid need not be refrigerated.

·         Macroscopic

·             The appearance, color and nature of the specimen were noted. Normally freshly passed urine is clear and pale yellow-to-yellow depending on the concentration. When left to Stand, cloudiness may develop due to precipitation of urates in acid urine or phosphates and carbonates in alkaline urine. Approximate number of bacteria per mL. of urine, can be estimated by using calibrated loop technique (0.002ml capacity or 1/500mL or 20x500-10,000) Dilute the Urine up to 10 ^-5 and perform Streak plate technique. (Normal urine had less than 4 bacterial cultures). Divided the nutrient agar plates into 6 portions and inoculate a loop full of urine on respective portion as single line. For selective isolation, mix urine properly and inoculate a loop full of Urine on blood agar, Mac Conkey agar CLED agar, cetrimide agar and SS agar. Incubate all plates at 37°Cfor 24 hours. Observed for colony and interpret the result.

Result

The urine sample contains E.coli, Klebsiella, Proteus and Pseudomonas aeruginosa.