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Incidence and spontaneous resolution of postpartum bacteriuria
Incidence and spontaneous resolution of postpartum bacteriuria ROBERT V. MARRARO, PH.D .. MAJOR. USAF. BSC ROBERT E. HARRIS. M.D., PH.D .. CoLONEL, USAF. MC Larkland Air Force Base,
Tt'XO.\
On the first postpartum day, 53 patients (17.2 per cent) had asymptomatic bacteriuria. Spontaneous resolution of bacteriuria occurred in 40 (75.5 per cent) of the 53 patients by the third postpartum day-the most appropriate time to identify patients with true asymptomatic bacteriuria. (AM. J. 0BSTET. GYNECOL. 128: 722, 1977.)
POSTPARTUM BACTERIURIA (>100,000 colonies per milliliter) has been reported to occur for 18.5 per cent of patients. 1 Prior postpartum studies at our institution2· 3 have shown that I 7 and 18 per cent of the patients, respectively, have asymptomatic bacteriuria (>I 00,000 colonies per milliliter) on the first postpartum dar. However, the incidence of confirmed bacteriuria by repeat cultures for these patients was found to vary between 2.7 and 3.0 per cent. 2 ' 3 Because of the low incidence of confirmed bacteriuria, a prospective study was undertaken to determine if spontaneous resolution of postpartum bacteriuria would occur and to ascertain the most appropriate day following delivery upon which to obtain a clinicallv meaningful urine culture.
of the specimen was cultured by the standard calibrated loop-direct streak method.~ Isolates were identified with standard techniques."· 6 For those patients with bacteriuria (>I 00,000 colonies per milliliter) on the third postpartum day, subsequent ronfirmatory urine cultures were obtained. All patients were instructed to return to the obstetri{: clinic if symptoms of urinary tract infection occurred during the period eight weeks post partum.
Results Urine specimens from 30R postpartum patient'\ were cultured. Asymptomatic bacteriuria was detected on the first postpartum day tiJf 53 of the 308 patient<> (17 .2 per cent), on the second postpartum day for 23 patients (7.5 per cent). and on the third postpartum day for 13 patients (4.2 per cent). Subsequent urine cultures confirmed persistent bacteriuria for these latter I 3 patients. Twelve of the 13 patients wt're treated with antibiotics, as indicated by the in vitro antibiogram studies, prior to onset of symptoms. The thirteenth patient returned to the obstetric clini<· with symptomatic cystitis prior to notification to begin antibiotic therapy. Spontaneous resolution was observed by the second postpartum day for 30 (56.5 per cent) of the initial 5?> bacteriuric patients. Additionally, by the third postpartum day, spontaneous resolution was noted for an additional 10 patients (18.9 per cent). Thus, these data indicated that by the third postpartum day spontaneous resolution of initial bacteriuria had occurred for 40 (75.5 per cent) of the 53 patients.
Material and methods For purposes of this study. only those patients delivered vaginally and who remained in the hospital fix the usual three postpartum days were evaluated. Catheterized patients or those receiving antibiotic therapy during the first three postpartum days were not included. A clean-catch, midstream urine sample was obtained from each of 308 patients on the first, second, and third days following delivery. An aliquot
From the Microbiology Branch, Clinical Pathology Service, and the Department of Obstetrics and Gynecology, Wilford HaU United States Air Forch Medical Center.
The views expressed herein are those of the authors and do not necessarily reflect the views of the United States Air Force or the Depar·tment of Defense. Received for publication October 12, 1976.
Comment The incidence of bacteriuria on the third p<>stpartum day (4.2 per cent) is comparable to the in-
Accepted Aprill4, 1977. Reprint requests: Dr. Robert E. Harris, 6402 Red JackRt Dr., San Antonio. Texas 78238.
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cidence of confirmed postpartum bacteriuria previously reported at this institution. 2• 3 In the present study, by the third postpartum day, bacteriuria (> 100,000 colonies per milliliter) was found to spontaneously resolve, i.e., no clinical intervention, for 7 5.5 per cent of the patients. lt would appear from these data that urine cultures obtained within 48 hours of delivery may reflect local bacterial contamination and not true bacteriuria. The reasons associated with this contamination may be the result of the anatomic and physiologic trauma of the birth process as well as difficulty in early postpartum urine collection. There may be factors other than these which might explain our data. However. it was not the purpose of this study to determine the site of bacterial shedding from the genitourinary tract.
Postpartum bacteriuria 723
Regardless of the factors involved, if the indication to initiate therapy is based upon the urine culture obtained on the first, as compared to the third, postpartum day, 75.5 per cent of these patients would be treated unnecessarily. The present study suggests that the most valid urine culture is obtained on the third postpartum day and, if confirmed bacteriuria persists, antibiotic therapy should be instituted. It is our opinion that this approach for evaluating postpartum bacteriuria will: (l) improve patient care, (2) avoid unwarranted antibiotic therapy, and (3) eliminate the expenses of both unnecessary postpartum urine cultures and prescribed medication.
REFERENCES 1. Hunt, C. F., and Hadley, R. P.: Incidence of postpartum bacteriuria in term vaginal deliveries, AM. ]. OssTET. GYNECOL. 96: 14, 1966. 2. Harris, R. E., and Marraro, R. V.: Reliability of the "Bacturcult" system in the clinical evaluation of postpartum bacteriuria, Obstet. Gvnecol. 49: 723, 1977. 3. Harris, R. E., Tho~s. V. L., and Hui, G.: Postpartum surveillance of urinary tract infections. South. Med. J. Accepted for publication.
4. Hoeprich, P. D.: Culture of the urine, J. Lab. Clin. Med. 56: 899, 1960. 5. Lennette, E. H., Spaulding, E. H., and Truant, J. P.: Manual of Clinical Microbiology, Ed. 2, Washington, D. C., 1974, American Society of Microbiology. 6. Baily, W. R., and Scott, E. G.: Diagnostic Microbiology. ed. 4, St. Louis, 1974, The C. V. Mosby Company.
Tt'XO.\
On the first postpartum day, 53 patients (17.2 per cent) had asymptomatic bacteriuria. Spontaneous resolution of bacteriuria occurred in 40 (75.5 per cent) of the 53 patients by the third postpartum day-the most appropriate time to identify patients with true asymptomatic bacteriuria. (AM. J. 0BSTET. GYNECOL. 128: 722, 1977.)
POSTPARTUM BACTERIURIA (>100,000 colonies per milliliter) has been reported to occur for 18.5 per cent of patients. 1 Prior postpartum studies at our institution2· 3 have shown that I 7 and 18 per cent of the patients, respectively, have asymptomatic bacteriuria (>I 00,000 colonies per milliliter) on the first postpartum dar. However, the incidence of confirmed bacteriuria by repeat cultures for these patients was found to vary between 2.7 and 3.0 per cent. 2 ' 3 Because of the low incidence of confirmed bacteriuria, a prospective study was undertaken to determine if spontaneous resolution of postpartum bacteriuria would occur and to ascertain the most appropriate day following delivery upon which to obtain a clinicallv meaningful urine culture.
of the specimen was cultured by the standard calibrated loop-direct streak method.~ Isolates were identified with standard techniques."· 6 For those patients with bacteriuria (>I 00,000 colonies per milliliter) on the third postpartum day, subsequent ronfirmatory urine cultures were obtained. All patients were instructed to return to the obstetri{: clinic if symptoms of urinary tract infection occurred during the period eight weeks post partum.
Results Urine specimens from 30R postpartum patient'\ were cultured. Asymptomatic bacteriuria was detected on the first postpartum day tiJf 53 of the 308 patient<> (17 .2 per cent), on the second postpartum day for 23 patients (7.5 per cent). and on the third postpartum day for 13 patients (4.2 per cent). Subsequent urine cultures confirmed persistent bacteriuria for these latter I 3 patients. Twelve of the 13 patients wt're treated with antibiotics, as indicated by the in vitro antibiogram studies, prior to onset of symptoms. The thirteenth patient returned to the obstetric clini<· with symptomatic cystitis prior to notification to begin antibiotic therapy. Spontaneous resolution was observed by the second postpartum day for 30 (56.5 per cent) of the initial 5?> bacteriuric patients. Additionally, by the third postpartum day, spontaneous resolution was noted for an additional 10 patients (18.9 per cent). Thus, these data indicated that by the third postpartum day spontaneous resolution of initial bacteriuria had occurred for 40 (75.5 per cent) of the 53 patients.
Material and methods For purposes of this study. only those patients delivered vaginally and who remained in the hospital fix the usual three postpartum days were evaluated. Catheterized patients or those receiving antibiotic therapy during the first three postpartum days were not included. A clean-catch, midstream urine sample was obtained from each of 308 patients on the first, second, and third days following delivery. An aliquot
From the Microbiology Branch, Clinical Pathology Service, and the Department of Obstetrics and Gynecology, Wilford HaU United States Air Forch Medical Center.
The views expressed herein are those of the authors and do not necessarily reflect the views of the United States Air Force or the Depar·tment of Defense. Received for publication October 12, 1976.
Comment The incidence of bacteriuria on the third p<>stpartum day (4.2 per cent) is comparable to the in-
Accepted Aprill4, 1977. Reprint requests: Dr. Robert E. Harris, 6402 Red JackRt Dr., San Antonio. Texas 78238.
722
Volume 128 Number 7
cidence of confirmed postpartum bacteriuria previously reported at this institution. 2• 3 In the present study, by the third postpartum day, bacteriuria (> 100,000 colonies per milliliter) was found to spontaneously resolve, i.e., no clinical intervention, for 7 5.5 per cent of the patients. lt would appear from these data that urine cultures obtained within 48 hours of delivery may reflect local bacterial contamination and not true bacteriuria. The reasons associated with this contamination may be the result of the anatomic and physiologic trauma of the birth process as well as difficulty in early postpartum urine collection. There may be factors other than these which might explain our data. However. it was not the purpose of this study to determine the site of bacterial shedding from the genitourinary tract.
Postpartum bacteriuria 723
Regardless of the factors involved, if the indication to initiate therapy is based upon the urine culture obtained on the first, as compared to the third, postpartum day, 75.5 per cent of these patients would be treated unnecessarily. The present study suggests that the most valid urine culture is obtained on the third postpartum day and, if confirmed bacteriuria persists, antibiotic therapy should be instituted. It is our opinion that this approach for evaluating postpartum bacteriuria will: (l) improve patient care, (2) avoid unwarranted antibiotic therapy, and (3) eliminate the expenses of both unnecessary postpartum urine cultures and prescribed medication.
REFERENCES 1. Hunt, C. F., and Hadley, R. P.: Incidence of postpartum bacteriuria in term vaginal deliveries, AM. ]. OssTET. GYNECOL. 96: 14, 1966. 2. Harris, R. E., and Marraro, R. V.: Reliability of the "Bacturcult" system in the clinical evaluation of postpartum bacteriuria, Obstet. Gvnecol. 49: 723, 1977. 3. Harris, R. E., Tho~s. V. L., and Hui, G.: Postpartum surveillance of urinary tract infections. South. Med. J. Accepted for publication.
4. Hoeprich, P. D.: Culture of the urine, J. Lab. Clin. Med. 56: 899, 1960. 5. Lennette, E. H., Spaulding, E. H., and Truant, J. P.: Manual of Clinical Microbiology, Ed. 2, Washington, D. C., 1974, American Society of Microbiology. 6. Baily, W. R., and Scott, E. G.: Diagnostic Microbiology. ed. 4, St. Louis, 1974, The C. V. Mosby Company.