Another retrospective population-based study comparing almost 220,000 singleton pregnancies of patients with and without acute pyelonephritis concluded that the infection is an independent risk factor for preterm delivery (Eur. J. Obstet. Gynecol. Reprod. Biol 2012;162:24-7).
After admission to the hospital, patients must be carefully monitored for uterine contractions and changes in vital signs and fetal heart rate. Several years ago, in an effort to empirically and synergistically target E. coli, the most common cause of UTIs and pyelonephritis, we began administering both an extended-spectrum cephalosporin (intravenous ceftriaxone) and an antimicrobial that will target gram-negative organisms, such as an aminoglycoside (gentamicin) or aztreonam.
We established this protocol because reviews of the outcomes at our institution indicated that intravenous ceftriaxone alone had not prevented some of our patients from developing septic shock in the first 8-20 hours post admission, despite the fact that culture and sensitivity results later indicated that the organism was E. coli and sensitive to the antimicrobial.
While we have not yet done any formal data analysis since changing our protocol, the combination parenteral antimicrobial regimen prescribed on admission appears to be effective in preventing the development of septic shock. We prescribe ceftriaxone 2 g intravenously once a day and gentamicin 5 mg/kg per day. Both drugs are continued until the patient improves clinically and has been afebrile for 48 hours.
At discharge, patients are prescribed a 10- to 14-day oral antimicrobial regimen dependent upon the culture and sensitivity report. Because at least 50% of E. coli are resistant to penicillin-like antimicrobials, the initial treatment no longer involves the use of ampicillin or amoxicillin. A repeat urine culture test at the end of treatment to confirm clearance of the infection is essential.
The possibility of anatomical obstructions in the urinary system should be investigated in pregnant patients who have multiple UTIs or who are unresponsive to appropriate antibiotic therapy for pyelonephritis. In this group we have performed ultrasound of the urinary tract system and have diagnosed renal stones as the risk factor for recurrent UTI. These patients are prescribed antimicrobial prophylaxis for the duration of the pregnancy. After delivery, they are referred to a urologist for follow-up care and treatment.
Dr. Apuzzio reported that he has no disclosures relevant to this Master Class.
Dr. Apuzzio is a professor in the department of obstetrics, gynecology, and women’s health, director of prenatal diagnosis and infectious diseases, professor of radiology, and director of maternal-fetal medicine at Rutgers New Jersey Medical School, Newark.