Lower Urinary Pathogens: Do More Pathogenic Bacteria Increase the Risk of Pyelonephritis?

Abstract

Objective Outside of pregnancy, urinary pathogens such as Proteus and Klebsiella are considered more pathogenic than E. coli. During pregnancy, the implications of lower urinary tract infection (LUTI) with more pathogenic bacteria are unclear. Thus, we sought to compare the risk of progression from LUTI to pyelonephritis among women infected with these more pathogenic urinary bacteria to those infected with E. coli.

Study Design Retrospective cohort of pregnant women with LUTI at single tertiary center from July 2013 to May 2019. Pathogenic infections (PI) were defined as asymptomatic bacteriuria or acute cystitis urinary cultures positive for Proteus, Klebsiella, Enterobacter, Citrobacter, Acinetobacter, Staphylococcus, or Raoultella species. Demographic, infectious, antepartum, and postpartum data abstracted. Pregnant women with PI compared with those with E. coli. Primary outcome was progression to pyelonephritis. Secondary outcomes included pyelonephritis length of stay (LOS) >6 days, preterm birth (PTB), low birthweight (LBW), and measures of pyelonephritis-related morbidity.

Results Of 686 pregnant women with LUTIs, 313 had urine culture growing out either PI or E. coli, with 59 (12%) growing PI and 254 (54%) growing E. coli. Women with PI were more likely to be African American, have chronic hypertension, and have history of preeclampsia. The primary species causing PI were Klebsiella (n = 29) and Proteus (n = 11). PI were not more likely to progress to pyelonephritis than E. coli LUTIs (10.9 vs. 14.5%; p = 0.67). Median LOS for pyelonephritis and other measures of pyelonephritis-related morbidity did not differ nor did PTB or LBW rates. After controlling for race, body mass index, history of preeclampsia, and history of pyelonephritis, PI were not associated with increased odds of progression to pyelonephritis (adjusted odds ratio: 0.69, 95% confidence interval: 0.27–1.80).

Conclusion Bacteria traditionally considered to be more pathogenic outside of pregnancy do not progress to pyelonephritis at higher rates than E. coli in pregnancy, and are associated with similar pyelonephritis-related morbidity. Larger studies are needed to confirm these findings.

Key Points

• Little is known about impact of uropathogen on progression to pyelonephritis and obstetric outcomes.

• Rates of progression to pyelonephritis from UTI did not vary by uropathogen.

• Pyelonephritis-related morbidities and preterm birth rates were also similar among uropathogens.

Keywords

pregnancy - pyelonephritis - anemia - sepsis - urinary tract infection - uropathogens

Note

This work was presented as poster presentation at the Society for Maternal–Fetal Medicine's 40th Annual Pregnancy meeting held in Dallas, TX, on February 3 to 8, 2020.

Publication History

Received: 11 August 2020

Accepted: 22 August 2020

Article published online:
24 September 2020

• References

• 1 Gilstrap III LC, Ramin SM. Urinary tract infections during pregnancy. Obstet Gynecol Clin North Am 2001; 28 (03) 581-591
• 2 Wing DA, Fassett MJ, Getahun D. Acute pyelonephritis in pregnancy: an 18-year retrospective analysis. Am J Obstet Gynecol 2014; 210 (03) 219.e1-219.e6
• 3 Farkash E, Weintraub AY, Sergienko R, Wiznitzer A, Zlotnik A, Sheiner E. Acute antepartum pyelonephritis in pregnancy: a critical analysis of risk factors and outcomes. Eur J Obstet Gynecol Reprod Biol 2012; 162 (01) 24-27
• 4 Nicolle LE, Bradley S, Colgan R, Rice JC, Schaeffer A, Hooton TM. Infectious Diseases Society of America, American Society of Nephrology, American Geriatric Society. Infectious Diseases Society of America guidelines for the diagnosis and treatment of asymptomatic bacteriuria in adults. Clin Infect Dis 2005; 40 (05) 643-654
• 5 Lin K, Fajardo K. U.S. Preventive Services Task Force. Screening for asymptomatic bacteriuria in adults: evidence for the U.S. Preventive Services Task Force reaffirmation recommendation statement. Ann Intern Med 2008; 149 (01) W20-4
• 6 Pediatrics AAo. Obstetricians ACo, Gynecologists. Amer Academy of Pediatrics; : Guidelines for Perinatal Care 2002
• 7 Ronald A. The etiology of urinary tract infection: traditional and emerging pathogens. Am J Med 2002; 113 (1, Suppl 1A): 14S-19S
• 8 Hooton TM, Roberts PL, Cox ME, Stapleton AE. Voided midstream urine culture and acute cystitis in premenopausal women. N Engl J Med 2013; 369 (20) 1883-1891
• 9 Czaja CA, Scholes D, Hooton TM, Stamm WE. Population-based epidemiologic analysis of acute pyelonephritis. Clin Infect Dis 2007; 45 (03) 273-280
• 10 Hill JB, Sheffield JS, McIntire DD, Wendel Jr GD. Acute pyelonephritis in pregnancy. Obstet Gynecol 2005; 105 (01) 18-23
• 11 American College of Obstetricians and Gynecologists. ACOG practice bulletin no. 95: anemia in pregnancy. Obstet Gynecol 2008; 112 (01) 201-207
• 12 Dotters-Katz SK, Grotegut CA, Heine RP. The effects of anemia on pregnancy outcome in patients with pyelonephritis. Infect Dis Obstet Gynecol 2013; 2013: 780960-780960
• 13 Smith C, Teng F, Branch E, Chu S, Joseph KS. Maternal and perinatal morbidity and mortality associated with anemia in pregnancy. Obstet Gynecol 2019; 134 (06) 1234-1244
• 14 Beckert RH, Baer RJ, Anderson JG, Jelliffe-Pawlowski LL, Rogers EE. Maternal anemia and pregnancy outcomes: a population-based study. J Perinatol 2019; 39 (07) 911-919