Reconsidering asymptomatic bacteriuria and contamination as causes of bacteriuria without pyuria

Abstract

Shaikh et al performed a meta-analysis to determine the prevalence of asymptomatic bacteriuria in children.1Shaikh N. Osio V.A. Wessel C.B. Jeong J.H. Prevalence of asymptomatic bacteriuria in children: a meta-analysis.J Pediatr. 2020; 217: 110-117.e4Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar The clinical issue is whether a positive urine culture with a negative urinalysis represents a urinary tract infection (UTI) or asymptomatic bacteriuria. The authors calculate the rate of bacteriuria without pyuria (the working definition of asymptomatic bacteriuria) to be 0.18% in boys and 0.38% in girls. They compare these rates with the 5% rate of what they call “UTIs,” determine the rate of asymptomatic bacteriuria to be “at least an order of magnitude less than the prevalence of UTI,” and conclude that “the current definition of UTI should be revisited.”1Shaikh N. Osio V.A. Wessel C.B. Jeong J.H. Prevalence of asymptomatic bacteriuria in children: a meta-analysis.J Pediatr. 2020; 217: 110-117.e4Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar However, the majority of the 5% have both bacteriuria and pyuria and clearly have a UTI, not asymptomatic bacteriuria. It is the remainder of the 5%—the 5%-15% with bacteriuria without pyuria—that should be compared with the prevalence of asymptomatic bacteriuria. Because 5%-15% of 5% is 0.25-0.75%, the rate in febrile children is similar to the prevalence of asymptomatic bacteriuria calculated by Shaikh et al. The authors not only dismiss asymptomatic bacteriuria as an explanation for bacteriuria without pyuria but contamination as well. There are ample data to refute their position, including specimens obtained by catheterization.2Lau A.Y. Wong S.N. Yip K.T. Fong K.W. Li S.P. Que T.L. A comparative study on bacterial cultures of urine samples obtained by clean-void technique versus urethral catheterization.Acta Pediatrica. 2007; 96: 432-436Crossref PubMed Scopus (22) Google Scholar, 3Wingerter S. Bachur R. Rick Factors for contamination of catheterized urine specimens in febrile children.Ped Emerg Care. 2011; 27: 1-4Crossref PubMed Scopus (25) Google Scholar, 4Eliacik K. Kanik A. Yavascan O. Alparslan C. Kocyigit C. Aksu N. et al.A comparison of bladder catheterization and suprapubic aspiration methods for urine sample collection from infants with a suspected urinary tract infection.Clin Pediatr. 2016; 55: 819-824Crossref PubMed Scopus (11) Google Scholar Fortunately, the combination of bacteriuria without inflammation (positive culture-negative urinalysis) occurs in only about 0.5% of febrile infants. Accordingly, the rate of missed bacteriuria is low when screened by urinalysis; moreover, the significance of bacteriuria without inflammation is not clear because inflammation appears to be required to cause renal scars.5Glauser M.P. Meylan P. Bille J. The inflammatory response and tissue damage. The example of renal scars following acute renal infection.Pediatr Nephrol. 1987; 1: 615-622Crossref PubMed Scopus (64) Google Scholar There is harm in presuming that bacteriuria without inflammation represents a UTI: treatment of asymptomatic bacteriuria increases the likelihood of a symptomatic UTI,6Kemper K. Avner E. The case against screening for asymptomatic bacteriuria in children.Am J Dis Child. 1992; 146: 343-346PubMed Google Scholar which would be mistaken as a recurrent UTI and trigger imaging, increasing cost, radiation, and discomfort. Prevalence of Asymptomatic Bacteriuria in Children: A Meta-AnalysisThe Journal of PediatricsVol. 217PreviewTo determine the point prevalence of bacteriuria and bacteriuria without pyuria in asymptomatic children by a systematic review of the literature. Full-Text PDF Editors' ResponseThe Journal of PediatricsVol. 223PreviewWe take this opportunity to comment on the letter to the editor from Drs Roberts and Wald, questioning the validity of the analysis and conclusion of the manuscript by Shaikh et al, and the authors' response. We believe that the analysis performed by Shaikh et al is sound and stand by the decision of The Journal to publish their study. We also choose to publish the letter and response to further enrich the deliberations of our readers. Full-Text PDF ReplyThe Journal of PediatricsVol. 223PreviewWe thank Drs Roberts and Wald for their interest in our article. However, the calculations presented in the first paragraph of their letter are misleading because they assume the “best case scenario” in favor of the authors' argument. Only when both prevalence of urinary tract infection (UTI) and false positive rate of on currently-available point-of-care tests for pyuria are 5% would the prevalence of true missed UTI without pyuria (ie, 0.25%) approach that of asymptomatic bacteriuria without pyuria (0.21%, the overall rate of asymptomatic bacteriuria without pyuria from our study). Full-Text PDF