Lower urinary tract infections ( Lower UTI ) in pregnancy and asymptomatic bacteriuria of pregnancy in adults ( ≥ 16 years of age ) - Guideline for the management of in secondary care
|Last review: 08/09/2017|
|Next review: 08/09/2020|
|Approved By: Trust Clinical Guidelines Group|
|Copyright© Leeds Teaching Hospitals NHS Trust 2017|
This Clinical Guideline is intended for use by healthcare professionals within Leeds unless otherwise stated.
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Lower urinary tract infections in pregnancy and asymptomatic bacteriuria of pregnancy in adults (≥ 16 years of age)
Lower urinary tract infections ( Lower UTI ) in pregnancy and asymptomatic bacteriuria of pregnancy in adults ( ≥ 16 years of age )
Lower urinary tract infections (lower UTIs/Cystitis)
+, *, ξ - See main guideline for notes
Asymptomatic bacteriuria of pregnancy
Recommendation: The diagnosis of a lower UTI is primarily based on symptoms and signs.
Symptoms and signs to classify a UTI are [Evidence level B]5:
Lower UTI: Dysuria and frequency without other features e.g. fever, back pain, loin pain or systemic features of infection.
Upper UTI: Dysuria, frequency and fever with other features including rigors, back pain, costovertebral angle (loin) pain which is usually unilateral and may worsen on micturition, nausea, vomiting and diarrhoea. Dysuria and frequency are not present in all cases of upper UTI. [Evidence level C]
If there are symptoms of upper UTI please see the upper UTI guideline. Upper UTI symptoms include costovertebral angle tenderness, back pain or where the severity of infection is not in keeping with a lower urinary tract infection e.g. hypotension or evidence of a Systemic Inflammatory Response Syndrome (SIRS).
If vaginal itch and/or discharge are present, consider alternative diagnoses such as vulvovaginitis (usually secondary to Candida) or chlamydial infection [Evidence level B].
Asymptomatic bacteriuria of pregnancy
A clinical diagnosis is not possible as this presentation is by definition asymptomatic [Evidence level B].
Recommendation: If a lower UTI is associated with systemic inflammatory response syndrome (SIRS) or severe sepsis please manage according to the upper UTI guideline.
Lower UTIs are not normally associated with SIRS [Evidence level B].
Asymptomatic bacteriuria of pregnancy [Evidence level B]
Evidence review/justification for recommendations
Interpretation of microbiology results
The interpretation of microbiology investigations for UTIs is heavily dependent upon the pre-test probability i.e. the probability of infection based on the clinical examination and history. For example, where there is a high probability of infection based on the clinical history negative microbiology results do not exclude a diagnosis of urinary tract infection.
Urine dipstick testing [Evidence level B]
Near patient testing using a commercially available dipstick test is rapid and reliable. It has a good negative predictive value i.e. if all the results are negative it is unlikely a patient has a UTI.
Dipstick results that have been used in the assessment of UTI include nitrite, leukocyte esterase, blood and protein.
Interpreting the urine dipstick result
Urine samples can be easily contaminated at the time of sampling. It is not possible to know this at the time of sampling although it may be suggested by the patient’s ability to provide a clean catch MSU. Contamination may be indicated when the sample is analysed in the laboratory, by a mixed growth and/or the presence of epithelial cells. [Evidence level B]
Nitrite positive: Evidence of UTI when combined with symptoms of a UTI.
Leucocyte esterase positive: Possible UTI though other causes of inflammation equally as likely.
Blood and/or protein positive: Not diagnostic of a UTI.
If negative (for nitrite, leukocyte esterase, protein and blood), then a urinary tract infection is unlikely, with a negative predictive value ≥ 95. If negative, urine sample should only be sent for microbiological investigations if there is high clinical suspicion of urinary tract infection, or from patients at particular risk of urinary tract infection/asymptomatic bacteriuria.
Laboratory urinary analysis (including culture) [Evidence level B]
The interpretation of urine samples is heavily dependent upon the clinical details and the method of urine collection. For example, in the absence of urinary symptoms any growth of bacteria is likely to represent asymptomatic bacteriuria or contamination. Asymptomatic bacteriuria is not a disease entity outside pregnancy and normally requires no treatment.
In the microbiology laboratory urine samples may undergo the following tests:
White cell count
Red cell count
Bacterial count and culture
Antibacterial susceptibility testing
Routine susceptibility testing of urines is standardised i.e. it is not different depending upon if a patient has upper or lower tract infection. Therefore not all antibiotics reported on urine culture results are suitable for the treatment of upper UTI. For example, Nitrofurantoin is suitable for the treatment of lower UTI but not upper UTI. The susceptibility testing completed and reported may be modified if clinical details provided by the requester reporting pregnancy.
Collecting urine sample(s) for Microbiology
Blood cultures [Evidence level B]
Both upper and lower tract UTI are likely to have urinalysis which suggests UTI.
Where patients have sepsis blood cultures should be taken.
Non microbiological investigation
Urine appearance: Production of turbid urine is reported to have a sensitivity of 90% and a specificity of 66% for the presence of symptomatic bacteriuria. This means if a patient has clear urine it is unlikely they have a UTI, but does not exclude it. It also means many patients with turbid urine do not have a UTI. Turbid urine should not in itself be used to diagnose a UTI. [Evidence level B]
Asymptomatic bacteriuria of pregnancy [Evidence level B] 8
Screening for asymptomatic bacteriuria
Screening for asymptomatic bacteriuria with urine dipsticks has an estimated sensitivity of 92%9. This sensitivity estimate is based on one study which compared urine dipsticks to two mid-stream urine samples. There are a number of studies which have compared the sensitivity of urine dipsticks to single mid-stream urine samples to estimate the sensitivity of dipsticks as a screen for asymptomatic bacteriuria. These studies estimate the sensitivity of urine dipsticks to be low at levels of 50-80%10. These estimates are low as using a single MSU sample to confirm asymptomatic bacteriuria is more likely to give a false positive result (the MSU result represents contamination), so underestimating the sensitivity of the urine dipstick. We therefore recommend patients should be screened for asymptomatic bacteriuria with urine dipsticks, and diagnosed using two MSU samples, as below. This recommendation is against a NICE recommendation which suggests MSU samples should be used to screen patients for asymptomatic bacteriuria. This has been declared by the trust as a NICE non-compliance,
Diagnosing asymptomatic bacteriuria
Asymptomatic bacteriuria is diagnosed by microbiological testing as there are no symptoms on which to make a diagnosis.
Asymptomatic bacteriuria is microbiologically diagnosed by confirming the growth of bacteria in the urine.
A growth of ≥104 bacteria/ml is a laboratory diagnosis of bacteriuria.
Asymptomatic bacteriuria may be associated with a normal or raised white cell count in the urine.
It is common for urines to be contaminated with uropathogens therefore a second urine demonstrating bacteriuria is required to confirm the diagnosis of asymptomatic bacteriuria. This proves the first sample did not represent contamination.
|Empirical Antimicrobial Treatment|
Lower Urinary Tract Infection in Pregnancy11/12
Antimicrobial recommendations are given in Table 1[Evidence level B-C]
In certain individual cases, including if recent antimicrobial therapy &/or previous bacteriology results available: an alternative empiric antimicrobial may be more suitable (consider discussing with Microbiology).
1Avoid in severe penicillin allergy
2Do not use nitrofurantoin liquid (due to costs). Seek advice from pharmacy and microbiology if this is a problem.
*Trimethoprim should be avoided in women with a low folate status (i.e. women with established folic acid deficiency, low dietary intake or already on folate antagonists) unless also taking a folate supplement. For women with a normal folate status, short term use of Trimethoprim is unlikely to induce folate deficiency.
The use of Trimethoprim should be considered carefully in the first trimester and should not be first line however: “In women with normal folate status, short-term use of Trimethoprim is unlikely to induce folate deficiency. Note: women who are pregnant, or at risk of pregnancy, should be taking folic acid until week 12 of their pregnancy in order to prevent neural tube defects in the foetus.
However, the BNF cautions against the use of Trimethoprim in the first trimester of pregnancy because the manufacturers recommend that it not be used then. The manufacturer's information leaflet also advises against the use of Trimethoprim for women who are pregnant or planning to become pregnant.”
ξ Nitrofurantoin : significant placental transfer of Nitrofurantoin does not occur. Nitrofurantoin has not been associated with an increased risk of congenital malformations. Nitrofurantoin has been associated with haemolysis in people with glucose-6-phosphate dyhydrogenase (G6PD) deficiency. However, the risk seems very small because placental transfer is so low. There is only one reported case of haemolytic anaemia in a new-born whose mother was treated at term with Nitrofurantoin .
Avoid in patients with suspected or known glucose-6-phosphate dehydrogenase (G-6-PD) deficiency.
Avoid Nitrofurantoin in patients with an estimated glomerular filtration rate (eGFR) of less than 45 ml/min.
Children have high rates of Clostridium difficile carriage e.g. 80% in <2 year olds. Pregnant women caring for children are therefore commonly exposed to C. difficile and the use of cephalosporins should be avoided where possible.
Some antimicrobials are contra-indicated in pregnancy – the British National Formulary (BNF) should be consulted, as required.
Asymptomatic bacteriuria of pregnancy13
A range of antibiotic regimens achieve cure of asymptomatic bacteriuria of pregnancy. There is insufficient data to show any particular antibiotic(s) have an advantage or comparing the efficacy of a three day vs. a seven day antimicrobial course in pregnancy [Evidence level B-C]
Most complications from asymptomatic bacteriuria occur late in pregnancy, and screening normally takes place in the first trimester. There is normally time to confirm the diagnosis with a second MSU before treating. On occasion it may not be possible to confirm the diagnosis and an individual decision is required to decide if treatment is indicated.
|Directed Antimicrobial Treatment (when microbiology results are known)|
Lower UTI in pregnancy and asymptomatic bacteriuria of pregnancy
When susceptibility results are available, therapy can be directed by the culture and susceptibility results. Select from the following antibiotics which are listed in order of preference (Table 3).
|Duration of Treatment|
Lower urinary tract infection in pregnancy and asymptomatic bacteriuria of pregnancy [Evidence level B]
Durations are given in Table 4.
+, *, ξ - See main guideline for notes
1Avoid in severe penicillin allergy
|Switch to oral agent(s)|
|See directed antimicrobial therapy above.|
Appendix 1: Flowchart for the Management of Urine Screening in Pregnancy
Ensure appropriate microbiological investigation i.e. clean catch MSU.
Consider alternative diagnoses e.g. chlamydial infection, candida vaginitis (thrush).
Lower urinary tract infections in pregnancy and asymptomatic bacteriuria of pregnancy
|Target patient group:||Adults (= 16 years of age)|
|Target professional group(s):||Pharmacists
Secondary Care Doctors
- Echols RM, Tosiello RL, Haverstock DC, Tice AD. Demographic, clinical, and treatment parameters influencing the outcome of acute cystitis. Clin Infect Dis. 1999; 29(1):113.
- Johansen TE, Botto H, Cek M, Grabe M, Tenke P, Wagenlehner FM, Naber KG. Critical review of current definitions of urinary tract infections and proposal of an EAU/ESIU classification system. Int J Antimicrob Agents. 2011 Dec; 38 Suppl: 64-70.
- Gilstrap LC 3rd, Ramin SM. Urinary tract infections during pregnancy. Obstet Gynecol Clin North Am. 2001; 28(3):581.
- Delzell JE Jr, Lefevre ML. Urinary tract infections during pregnancy. Am Fam Physician. 2000;61(3):713
- Sobel J D and Kaye D. Urinary tract infections. In: Mandell GL, Bennett JE, Dolin R. (eds) Principles and Practice of Infectious Diseases 7th Edn 2009 875-905.
- SIGN Management of suspected bacterial urinary tract infection in adults A national clinical guideline July 2006]
- 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 Mar 1; 40(5):643-54.
- Robertson AW, Duff P. The nitrite and leukocyte esterase tests for the evaluation of asymptomatic bacteriuria in obstetricpatients. Obstet Gynecol 1988; 71(6 Pt 1):878-81.
- NICE Antenatal care: Routine care for the healthy pregnant woman. CG62. 2008.
- Gupta K, Hooton TM, Naber KG, Wullt B, Colgan R, Miller LG, Moran GJ, Nicolle LE, Raz R, Schaeffer AJ, Soper DE. International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases. Clin Infect Dis. 2011 Mar 1; 52(5):e103-20.
- Nicolle LE, Bradley S, Colgan R, Rice JC, Schaeffer A, Hooton TM. Infectious Diseases Society of America guidelines for the diagnosis and treatment of asymptomatic bacteriuria in adults. Clin Infect Dis. 2005 Mar 1; 40(5):643-54.
A. Meta-analyses, randomised controlled trials/systematic reviews of RCTs
B. Robust experimental or observational studies
C. Expert consensus.
D. Leeds consensus. (where no national guidance exists or there is wide disagreement with a level C recommendation or where national guidance documents contradict each other)
Trust Clinical Guidelines Group
LHP version 1.0
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