Urinary tract infection in full-term newborn infants: risk factor analysis.

OBJECTIVE: To analyze the correlation of risk factors to the occurrence of urinary tract infection in full-term newborn infants. PATIENTS AND METHODS: Retrospective study (1997) including full-term infants having a positive urine culture by bag specimen. Urine collection was based on: fever, weight loss > 10% of birth weight, nonspecific symptoms (feeding intolerance, failure to thrive, hypoactivity, debilitate suction, irritability), or renal and urinary tract malformations. In these cases, another urine culture by suprapubic bladder aspiration was collected to confirm the diagnosis. To compare and validate the risk factors in each group, the selected cases were divided into two groups: Group I - positive urine culture by bag specimen collection and negative urine culture by suprapubic aspiration, and Group II - positive urine culture by bag specimen collection and positive urine culture by suprapubic aspiration. RESULTS: Sixty one infants were studied, Group I, n = 42 (68.9%) and Group II, n = 19 (31.1%). The selected risk factors (associated infectious diseases, use of broad-spectrum antibiotics, renal and urinary tract malformations, mechanical ventilation, parenteral nutrition and intravascular catheter) were more frequent in Group II (p<0.05). Through relative risk analysis, risk factors were, in decreasing importance: parenteral nutrition, intravascular catheter, associated infectious diseases, use of broad-spectrum antibiotics, mechanical ventilation, and renal and urinary tract malformations. CONCLUSION: The results showed that parenteral nutrition, intravascular catheter, and associated infectious diseases contributed to increase the frequency of neonatal urinary tract infection, and in the presence of more than one risk factor, the occurrence of urinary tract infection rose up to 11 times.

Urinary tract infection in full-term newborn infants: value of urine culture by bag specimen collection.

OBJECTIVE: To evaluate the efficacy of urine culture by bag specimen for the detection of neonatal urinary tract infection in full-term newborn infants. Retrospective study (1997) including full-term newborn infants having a positive urine culture (> 100,000 CFU/ml) by bag specimen collection. The urinary tract infection diagnosis was confirmed by positive urine culture (suprapubic bladder aspiration method). The select cases were divided into three groups, according to newborn infant age at the bag specimen collection: GI (< 48 h, n = 17), GII (48 h to 7 d, n = 35) and GIII (> 7 d, n = 9). Sixty one full-term newborn infants were studied (5.1% of total infants). The diagnosis was confirmed on 19/61 (31.1%) of full-term infants born alive. Distribution among the groups was: GI = 2/17 (11.8%), GII = 10/35 (28.6%), and GIII = 7/9 (77.7%). The most relevant clinical symptoms were: fever (GI--100%, GII--91.4%) and weight loss (GI--35.3%, GII--45.7%). Urine culture results for specimens collected by suprapubic aspiration were: E. coli GI (100%), GII (40%) and GIII (28.6%), E. faecalis GI (30%), Staphylococcus coagulase-negative GII (20%) and GIII (42.8%), and Staphylococcus aureus GII (10%). Correlation between positive urine culture collection (bag specimen method) and urinary tract infection diagnosis, using relative risk analysis, produced the following results: GI = 0.30 (CI 95% 0.08-1.15), GII = 0.51 (CI 95% 0.25-1.06) and GIII = 3.31 (CI 95% 1.8-6.06). The most frequent urinary tract infection clinical signs in the first week were fever and weight loss, while non-specific symptomatology occurred later. E. coli was most frequent infectious agent, although from the 7th day of life, staphylococcus was noted. The urine culture (bag specimen method) was effective in detecting urinary tract infection only after the 7th day of life.