Original Studies
Factors Associated With Bacteremia in Young Infants With Urinary Tract Infection Diana Averbuch, MD,*† Ran Nir-Paz, MD,‡ Ariel Tenenbaum, MD,§ Polina Stepensky, MD,* Rebecca Brooks, MD,§ Benjamin Z. Koplewitz, MD,¶ Ari M. Simckes, MD,*‖ and Dan Engelhard, MD*†** Background: Urinary tract infection (UTI) is the most frequent severe bacterial infection in infants. Up to 31% of infants with UTI have bacteremia. Methods: We retrospectively identified all infants aged 0–2 months who were managed in our hospital with UTI during a 1-year period. Those with bacteremia were compared with those without bacteremia, according to the following variables: ethnicity, age, gender, white blood cell and polymorphonuclear counts, C-reactive protein, urinalysis and blood creatinine values as related to age-appropriate norms, imaging and outcome. Results: We identified 81 infants with 82 episodes of UTI. Most occurred in males (72.8%) and 35 (42.7%) were in infants of non-Jewish origin. In 14/81 (17.3%) of episodes, Escherichia coli was cultured from blood. In multivariate analysis, increased blood creatinine levels (P = 0.004) and non-Jewish origin (P = 0.006) were associated with bacteremia. Time to defervescence was significantly longer in bacteremic versus nonbacteremic children (P = 0.018). Duration of hospitalization was longer in bacteremic infants—10 (7–17) days in bacteremic versus 7 (1–14) days in nonbacteremic children (P < 0.001). Conclusions: In infants aged 0–2 months with UTI, increased blood creatinine value at admission was associated with bacteremia. This value provides an additional clue on admission, independent of personal judgment, to help identify infants at higher risk for bacteremia, prolonged hospitalization and possible complications. Key Words: urinary tract infection, neonates, bacteremia, renal function (Pediatr Infect Dis J 2014;33:571–575)
U
rinary tract infection (UTI) is one of the most common causes of serious bacterial infections in infants 9 cells/high power field can predict bacteremia, although others have not found this association.11–16,23,35,36 The rate of bacteremia (17%) in our study was in the middle of the range reported in other studies (0–31%). The wide range in occurrence of bacteremia may be explained by the different numbers and age ranges of children included in these studies.5,7,8,11–16,19,35 Several studies have reported the benign course of UTI in infants, even when accompanied by bacteremia, although the bacteremia rate was low in these studies,4–9 making comparison between bacteremic and nonbacteremic episodes problematic.11,13,35,36 The course of illness was relatively benign in the children in our study too, except for longer time to defervescence in the bacteremic children. However, identification at admission of those infants who are bacteremic may be important according to the results of one much bigger study with high number (n = 123) of bacteremic infants aged www.pidj.com | 573
Averbuch et al
The Pediatric Infectious Disease Journal • Volume 33, Number 6, June 2014
29–60 days which reported a significantly higher frequency of complications (defined as: death, shock, bacterial meningitis, intensive care unit or step-down intensive care unit admission or transfer, need for ventilator support, need for surgical intervention or other substantial clinical complication) in infants with bacteremic UTI compared with those with UTI without bacteremia (10/123, 8.1% vs. 41/1754, 2.3%).15 Ill appearance at presentation can help predict these adverse events, but clinical judgment depends on the personal experience of the treating physician. Increased blood creatinine level provides an additional clue, independent of personal judgment, which may help identify infants at higher risk for bacteremia and for complications. Median duration of hospitalization and parenteral therapy was 7 days in our study, being significantly longer in bacteremic infants, similar to other studies.36,37 There is a tendency to shorten significantly parenteral therapy for UTI at any age or even to provide oral therapy initially based on several studies which showed equal efficacy of oral and parenteral therapy for children with UTI, regardless of bacteremia. However, the proportion of children with bacteremia was small in these studies and the proportion of infants in the first 3 months of life was low, some of the studies excluded infants
Factors Associated With Bacteremia in Young Infants With Urinary Tract Infection Diana Averbuch, MD,*† Ran Nir-Paz, MD,‡ Ariel Tenenbaum, MD,§ Polina Stepensky, MD,* Rebecca Brooks, MD,§ Benjamin Z. Koplewitz, MD,¶ Ari M. Simckes, MD,*‖ and Dan Engelhard, MD*†** Background: Urinary tract infection (UTI) is the most frequent severe bacterial infection in infants. Up to 31% of infants with UTI have bacteremia. Methods: We retrospectively identified all infants aged 0–2 months who were managed in our hospital with UTI during a 1-year period. Those with bacteremia were compared with those without bacteremia, according to the following variables: ethnicity, age, gender, white blood cell and polymorphonuclear counts, C-reactive protein, urinalysis and blood creatinine values as related to age-appropriate norms, imaging and outcome. Results: We identified 81 infants with 82 episodes of UTI. Most occurred in males (72.8%) and 35 (42.7%) were in infants of non-Jewish origin. In 14/81 (17.3%) of episodes, Escherichia coli was cultured from blood. In multivariate analysis, increased blood creatinine levels (P = 0.004) and non-Jewish origin (P = 0.006) were associated with bacteremia. Time to defervescence was significantly longer in bacteremic versus nonbacteremic children (P = 0.018). Duration of hospitalization was longer in bacteremic infants—10 (7–17) days in bacteremic versus 7 (1–14) days in nonbacteremic children (P < 0.001). Conclusions: In infants aged 0–2 months with UTI, increased blood creatinine value at admission was associated with bacteremia. This value provides an additional clue on admission, independent of personal judgment, to help identify infants at higher risk for bacteremia, prolonged hospitalization and possible complications. Key Words: urinary tract infection, neonates, bacteremia, renal function (Pediatr Infect Dis J 2014;33:571–575)
U
rinary tract infection (UTI) is one of the most common causes of serious bacterial infections in infants 9 cells/high power field can predict bacteremia, although others have not found this association.11–16,23,35,36 The rate of bacteremia (17%) in our study was in the middle of the range reported in other studies (0–31%). The wide range in occurrence of bacteremia may be explained by the different numbers and age ranges of children included in these studies.5,7,8,11–16,19,35 Several studies have reported the benign course of UTI in infants, even when accompanied by bacteremia, although the bacteremia rate was low in these studies,4–9 making comparison between bacteremic and nonbacteremic episodes problematic.11,13,35,36 The course of illness was relatively benign in the children in our study too, except for longer time to defervescence in the bacteremic children. However, identification at admission of those infants who are bacteremic may be important according to the results of one much bigger study with high number (n = 123) of bacteremic infants aged www.pidj.com | 573
Averbuch et al
The Pediatric Infectious Disease Journal • Volume 33, Number 6, June 2014
29–60 days which reported a significantly higher frequency of complications (defined as: death, shock, bacterial meningitis, intensive care unit or step-down intensive care unit admission or transfer, need for ventilator support, need for surgical intervention or other substantial clinical complication) in infants with bacteremic UTI compared with those with UTI without bacteremia (10/123, 8.1% vs. 41/1754, 2.3%).15 Ill appearance at presentation can help predict these adverse events, but clinical judgment depends on the personal experience of the treating physician. Increased blood creatinine level provides an additional clue, independent of personal judgment, which may help identify infants at higher risk for bacteremia and for complications. Median duration of hospitalization and parenteral therapy was 7 days in our study, being significantly longer in bacteremic infants, similar to other studies.36,37 There is a tendency to shorten significantly parenteral therapy for UTI at any age or even to provide oral therapy initially based on several studies which showed equal efficacy of oral and parenteral therapy for children with UTI, regardless of bacteremia. However, the proportion of children with bacteremia was small in these studies and the proportion of infants in the first 3 months of life was low, some of the studies excluded infants
