Bacteriuria during pregnancy: treatment and effect on the fetus

During pregnancy, women's health is subjected to a serious test: in addition to drastic hormonal changes, the expectant mother's body is undergoing a global restructuring with the displacement of internal organs due to the growing uterus, and the redistribution of resources, which should now be enough for two. Therefore, it is not surprising that over the course of 9 long months, pregnant women experience aggravation of many chronic ailments, and, in addition, deviations in the functioning of internal organs appear, for which, it would seem, there are no prerequisites. One of the fairly common companions of pregnancy is bacteriuria, which can be asymptomatic or accompanied by some discomfort. Where does atypical microflora appear in the urine of a pregnant woman, what is the threat of such a deviation to the expectant mother and her baby, and how to recognize bacteriuria if it is asymptomatic? Knowing the answers to these questions, you will be able to identify the disease in time and take appropriate measures to eliminate it!

Features of the pathology

If during pregnancy the kidneys cope with the functions assigned to them, and the genitourinary system works without “failures”, the urine released from the body is devoid of any microflora, that is, it is sterile. However, with the slightest deviation in the functionality of the internal organs of the excretory system, all kinds of pathogenic and opportunistic bacteria can appear in it, the presence of which can be confirmed by at least a double analysis. If each of the analyzed portions contains at least 100 thousand bacteria of the same type in each milliliter of physiological fluid, the doctor diagnoses true bacteriuria.

Bacteriuria during pregnancy can occur in two forms:

• an asymptomatic disease that does not manifest itself in any way except for deviations in test results;
• bacteriuria with characteristic symptoms, which may include pain in the lower abdomen, burning sensation when urinating, nagging pain in the back, slight increase in temperature, etc.

Despite the fact that asymptomatic bacteriuria does not cause any discomfort to the expectant mother, this form of the disease is more insidious than symptomatic, since it is unrealistic to suspect the occurrence of pathology. Therefore, during pregnancy, patients have to undergo a general urine test before each appointment - only in this way can they not miss the appearance of the first signs of the disease and take timely measures.

Where can bacteria come from in urine?

Bacteriuria, especially asymptomatic ones, is far from uncommon during pregnancy. According to statistics, such a deviation is detected on average in 6-11% of pregnant women at different stages. In some cases, bacteriuria may precede conception, but not be detected until a certain moment: while the body copes with the load, the immune system manages to keep the quantity and localization of pathogenic microflora under control, but at the slightest failure the disease begins to manifest itself, first in tests, and then symptomatically .

Typically, urine tests during pregnancy show:

• coli,
• streptococci,
• staphylococci,
• enterococci.

Such microflora is not foreign to the body - normally these pathogens are present in the gastrointestinal tract (in particular, in the intestines), as well as on the skin and mucous membranes. However, they should not be in the urine - this indicates a specific pathology.

Bacteriuria itself during pregnancy is not so dangerous and is quite easily curable, but in some cases this condition is not a specific disease, but a symptom of a more serious disorder. Thus, microorganisms can appear against the background of infectious processes in the urinary system, chronic pyelonephritis, kidney stones, dilation of the ureters or vesicoureteral reflux.

Bacteria in urine in pregnant women

Increased interest in the presence of bacteria in urine during pregnancy is due not only to the widespread prevalence of urinary tract infections, but also to the fact that BD often causes complications during pregnancy and infection of the mother-fetus system.

According to the literature, pregnant women with an infectious process in the urinary system are approximately 20-50% more likely to have children with signs of intrauterine infection.

Asymptomatic bacteriuria during pregnancy is one of the most common types of urinary tract infections and reaches a frequency of 16.5% (11). Most often, bacteriuria is considered as a risk factor for pyelonephritis.

The main aspects of the negative impact of asymptomatic bacteriuria in pregnant women:

1. 1During gestation, bacteriuria can develop into a clinically manifested urological disease (usually pyelonephritis). Thus, the incidence of pyelonephritis in healthy pregnant women is only 2.8%, while in women with bacteriuria in the absence of treatment this figure can reach up to 30%. A number of authors claim that treatment of asymptomatic bacteriuria during early pregnancy prevents the occurrence of acute pyelonephritis in 80% of cases.
2. 2The presence of a focus of chronic infection, even in the absence of symptoms, often leads to intrauterine infection of the fetus, threat of miscarriage, impaired placental attachment, polyhydramnios, and uteroplacental insufficiency.
3. 3Pregnant women with bacteriuria have a higher incidence of miscarriage, risk of late delivery and low birth weight babies.
4. 4In the presence of asymptomatic bacteriuria, the risk of placental pathology is higher, which can be expressed in impaired differentiation of chorionic villi, thrombosis of the intervillous space and inflammation of the membranes.
5. 5The impact of bacteriuria in pregnant women on the fetus is reduced to an increased risk of fetal infection (IUI) and an increased risk of intrauterine growth retardation.

2.1. Diagnostic criteria

The proven negative impact of bacteriuria on the body of the mother and fetus makes it important for its timely detection using the following criteria:

1. 1Detection of more than 10x5 CFU/ml of bacteria of the same species in two different bacteriological cultures of urine prescribed at intervals of at least 24 hours (days) in pregnant women who do not have signs of a urinary tract infection.
2. 2Single detection of more than 10x5 CFU/ml of pathogenic bacteria when collecting urine using a urinary catheter.

The severity of the listed diagnostic criteria is due to the fact that with a single culture of urine in pregnant women, in approximately 35-40% of cases, contamination with microorganisms from the skin of the perineum is possible.

That is why double urine culture is recommended to protect the fetus and the pregnant woman from unjustified antibiotic therapy.

Today, the most important criterion for BD (the presence of bacteria in the urine more than 10x5 CFU/ml) has been criticized as overly strict for pregnant women, but is justified as rational, in connection with the results of studies in which the excretion of bacteria in the urine in a titer of 10x4 led to increased number of pregnancy complications.

In Russia, clinical examination of pregnant women with double urine culture for the presence of bacteriuria is still not carried out due to the relative high cost, however, it is planned to introduce more accessible diagnostic methods and test systems (Display, paper rapid tests) in the near future..

Factors provoking asymptomatic bacteriuria in pregnant women

In some cases, bacteriuria appears on its own, without any other pathologies. This condition occurs especially often against the background of physiological changes characteristic of pregnancy. There are several predisposing nuances for the appearance of microorganisms during gestation:

• Changes in the genitourinary organs. During pregnancy, the functioning of the bladder sphincter is usually disrupted, the renal calyces and pelvis dilate, and the tone of the ureters decreases. This anatomical feature can provoke the introduction of infection into the excretory organs and, as a result, the appearance of asymptomatic bacteriuria.
• Active growth of the uterus. A sharp enlargement of the uterus causes a displacement of all internal organs of the abdominal cavity, but the greatest pressure falls on the kidneys and bladder. All this cannot but affect the performance of the excretory system, causing various disorders, including bacteriuria.

• Indigestion. Frequent constipation due to colon displacement and less active peristalsis is another reason for changes in the composition of urine.
• Hormonal changes. The high level of progesterone in the body, characteristic of normal pregnancy, reduces the tone of the ureters, as a result of which bacteria of various origins can appear in the urine.
• Composition of urine. During pregnancy, the urine pH becomes higher and a higher percentage of estrogen appears in it. This environment is more favorable for microbial growth, so the number of pathogenic microorganisms increases exponentially.
• Immunity problems. During pregnancy, the effectiveness of the immune system decreases for many reasons, so it becomes more difficult for the body to resist pathogenic microflora.
• Stagnation of urine. A low level of bladder tone provokes stagnation, in which some of the fluid is not released during urination. This allows microbes to actively multiply and develop, causing asymptomatic bacteriuria.

BACTERIURIA

BACTERIURIA

(
bacteriuria
; bacteria] + Greek uron urine; synonym
bacilluria
) - the presence of bacteria in freshly released urine.

Bacteria can enter the urine in various ways: from inflammatory foci of the kidneys, bladder, prostate gland or glands of the posterior urethra, during instrumental interventions (catheterization, cystoscopy, bougienage, stone crushing, etc.). It has been established that microbes do not penetrate from the bloodstream into the urine through intact kidneys. Therefore, the division of bacteriuria into true, when microbes vegetate and multiply in the urinary tract, and false, in which microbes supposedly enter from the blood through the kidney without multiplying, is incorrect. Microbes can multiply both in the affected organ (for example, in kidney tissue with pyelonephritis) and in urine, which is a good breeding ground for them. In this case, an increase in the degree of bacteriuria due to the proliferation of bacteria in the renal pelvis and ureter occurs only with stasis of urine in the upper urinary tract (complete or partial occlusion of the ureter, etc.). Microorganisms multiply in the bladder from any source of infection. The severity of bacteriuria is greater the longer the infected urine remains in the bladder, that is, the less often the patient empties the bladder. Pathological processes leading to impaired bladder emptying, for example, prostate adenoma, urethral stricture, congenital phimosis, etc., are important.

Since microflora often grows in the anterior section of the urethra, bacteria are sometimes found in the urine of healthy people. Therefore, it is extremely important to distinguish bacteriuria caused by pyelonephritis, cystitis or other inflammatory diseases from urine contamination by constantly vegetating microflora of the urethra.

Bacteriuria can be detected by determining the content of the number of microbes in 1 ml of the average portion of urine obtained during urination, determining the content of bacteria in the initial and average portions of urine, as well as culturing urine obtained using a suprapubic puncture of the bladder on special media (this method excludes the entry of microbes into urine from the urethra, but it is complex and therefore its use is limited).

Kass (EH Kass, 1956) was the first to describe the role of bacteriuria in the diagnosis of inflammatory diseases of the kidneys and urinary tract. He introduced quantitative methods for determining bacteriuria into clinical practice. According to Kass, during a purulent-inflammatory process in the kidneys or urinary tract, the patient’s urine always contains 100,000 or more microbes in 1 ml of urine, whereas when the urine is contaminated by the microflora of the urethra, the number of bacteria in 1 ml of urine never reaches such large values.

Rice. 1. Microscopic picture of urine sediment with bacteriuria (bright-field phase-contrast device); 1 - Escherichia coli, 2 - leukocytes, 3 - amorphous phosphates and tripelphosphates. Rice. 2. Microscopic picture of urine sediment during bacteriuria (dark-field phase-contrast device): 1 - Escherichia coli, 2 - leukocytes.

The severity of bacteriuria is determined by various methods: urine culture on various nutrient media; microscopy of urine sediment using bright-field (FK-4) and dark-field (MFA-2) phase-contrast devices (Fig. 1 and 2); using chemical tests. The simplest and most accurate method turned out to be a simplified method of inoculating urine with a sterile platinum loop on agar in certain sectors of a Petri dish according to Gould.

Three detection methods are used in clinical practice

bacteriuria using chemical tests: the nitrite test proposed by P. Griess (1879) as modified by JD Sleigh (1965), based on the reduction of nitrates contained in urine under the influence of bacteria into nitrites; TTX test proposed by Simmons and Williams (NA Simmons, JD Williams, 1962), based on the reduction of colorless triphenyltetrazolium chloride to red triphenylformazan in the presence of microbes in the urine; Braude's test (AJ Braude, 1959), based on the release of oxygen bubbles after adding 3% hydrogen peroxide to urine under the influence of catalase secreted by bacteria.

According to V. S. Ryabinsky (1969), a high degree of bacteriuria, that is, the content of 100,000 or more microbes in 1 ml of urine, is observed in 64.4% of patients with acute pyelonephritis and in 62.6% of patients with chronic pyelonephritis. The rest of the patients with pyelonephritis have no microbes in their urine or contain them in small quantities. In the latter case, in order to identify bacteriuria, bacteriological examination of the first and second portions of urine is indicated. The first portion of urine is inoculated on one Petri dish, and the second on another. If urine is contaminated by the microflora of the urethra, the growth of bacterial colonies will be only in the first Petri dish, or the number of colonies in the second Petri dish will be significantly less.

In some cases, bacteriuria occurs without clinical signs of damage to the organs of the urinary system, in others - as cystitis, pyelonephritis, prostatitis, urethritis. Low-grade or hectic temperature and urination problems are observed. The urine becomes cloudy due to the large number of microbes; when standing or centrifuging, a sediment forms with difficulty or does not form at all. The reaction of urine varies depending on the flora.

Treatment

in case of bacteriuria, it should be aimed at eliminating the source of infection in the body, eliminating the impaired passage of urine, and increasing the reactive forces of the body. Antibiotics, nitrofurans, sulfonamide drugs and chemotherapy drugs (hexamethylenetetramine, 5-NOK, nevigramon, etc.) are prescribed; dietary and spa treatment is indicated. The prognosis for bacteriuria depends on the cause that caused it.

Epidemiological significance

bacteriuria is determined by the possibility of the spread of pathogens belonging mainly to the group of infections with a fecal-oral transmission mechanism (typhoid fever, paratyphoid fevers A and B, etc.). In this case, the main epidemiological danger is posed by bacteria carriers (to a much lesser extent, patients and convalescents), in whom the excretion of typhoid or paratyphoid bacteria in the urine is observed for a long time. The epidemiological significance of bacteriuria in this case, in addition to its duration, is determined by the massive excretion of the pathogen in the urine, the effectiveness of the organization of anti-epidemic measures (dispensary observation) and largely depends on the degree of sanitary culture of the bacteria carrier.

Bacteriuria occurs in 1/3 of patients with typhoid fever and rarely in convalescents. Bacteriuria is of less epidemiological significance in brucellosis (approximately 10% of cases) and leptospirosis. With leptospirosis, the most dangerous epidemiologically is the entry of leptospira with urine into water sources. With diphtheria, tularemia, dysentery and other infections, the epidemiological significance of bacteriuria is extremely insignificant.

Bacteriuria, which occurs in a number of viral (influenza, epidemic hepatitis, measles, etc.) and fungal diseases, has not been sufficiently studied epidemiologically.

Bibliography:

Pytel A. Ya. and Goligorsky S. D. Selected chapters of nephrology and urology, part 1, p. 163, L., 1968; they are also, Inflammatory nonspecific diseases of the kidneys and ureters, Guide to wedge, urol., ed. A. Ya. Pytelya, p. 340, M., 1969; Urinary tract infection, ed. by F. O'Grady a. W. Brumfitt, p. 81 ao, L. ao, 1968.

V. S. Ryabinsky; A. A. Sumarokov, L. F. Kolobova (epid.).

Is a change in microflora dangerous for the mother and fetus?

Bacteriuria itself does not have a direct effect on the fetus, but during pregnancy it can cause many unpleasant consequences. Since the excretory system is adjacent to the reproductive system, pathogenic bacteria can spread to the walls of the uterus, affect the fetal membranes and, accordingly, the child in the womb. This condition significantly increases the risks:

• development of intrauterine infection,
• premature rupture of membranes and, as a consequence, childbirth,
• the birth of low birth weight newborns weighing less than 2.5 kg.

That is why obstetricians and gynecologists try to monitor the dynamics of pregnant women’s tests in order to promptly begin adequate therapy for asymptomatic bacteriuria and help the woman carry a healthy baby.

How to confirm the diagnosis?

Diagnosing asymptomatic bacteriuria is quite difficult, since it does not manifest itself in any way. Pathology can only be suspected if leukocytes or a high number of microorganisms are detected in the urine (more than 105 per 1 ml).

Important! Even if bacteria appeared in one of the tests, this does not mean that there are pathologies in the pregnant woman’s body - perhaps a specific portion was selected incorrectly. Therefore, to confirm the diagnosis, a minimum of 2 repeat tests are required with an interval of no more than 24 hours - only in this case can we talk about making a specific diagnosis.

If there is any suspicion, the pregnant woman is subjected to a special screening test with the TTX reagent, which gives a positive result in the presence of bacteriuria. To clarify the clinical form of the disease and the degree of its development, a more comprehensive examination is required, which usually includes the following activities:

• General and biochemical blood tests will reveal the presence of infectious processes that occur in an asymptomatic form;
• biochemical analysis of urine and a study of daily diuresis according to Nechiporenko will demonstrate how well the excretory system copes with the functions assigned to it;
• bacteriological urine culture will confirm the presence of asymptomatic bacteriuria and help assess the sensitivity of microorganisms to antibacterial therapy;
• ultrasound of the kidneys will help to clearly demonstrate the anatomical features and possible changes in the structure of organs during pregnancy;
• Dopplerometry of the excretory system will allow you to assess the blood supply to the genitourinary system.

Important! Bacteriological culture should be repeated twice with an interval of 3-7 days. If the quantitative content of bacteria and their sensitivity to antibiotics turns out to be identical in both samples, the result can be considered correct.

The influence of asymptomatic bacteriuria on the course of pregnancy and childbirth

 The purpose of this study was to study the effect of asymptomatic bacteriuria on the occurrence of complications of pregnancy and childbirth. Outpatient records of 328 pregnant women were analyzed for 2018. Among them, true bacteriuria was detected in 21 (6.4%) women. In terms of age, the bulk were women aged 21 to 30 years. Women with second and third pregnancies predominated (87.2%). No clinical symptoms were detected in any of the pregnant women. Complications of this pregnancy in 45.3% were preeclampsia. A significant level of threat of premature birth was also revealed - 25.7%. It is necessary to carry out prevention of infectious diseases in pregnant women and timely diagnosis. If asymptomatic bacteriuria is established, begin high-quality antibiotic therapy. Treatment of BB in pregnant women leads to a reduction in the risk of preterm birth or low birth weight babies.

Key words: asymptomatic bacteriuria, genitourinary system, commensal colonization, focus of chronic infection, complications of pregnancy and childbirth.

Introduction. The presence of bacteria in the urine of pregnant women without any clinical and laboratory signs of inflammation in the genitourinary system of an infectious nature is often observed and from infectious-inflammatory urological diseases is common and refers to commensal colonization. The definition of asymptomatic bacteriuria (AS) includes the following: bacteriuria equal to or greater than 105 CFU/ml in two consecutive urine samples collected in compliance with the rules of hygiene at least 24 hours apart when the same type of bacteria is detected and without a clinical picture of infection [ 1]. Asymptomatic bacteriuria in pregnant women is detected in 21.3% of cases per 100 thousand. This diagnosis is classified as a high-risk group for the development of acute cystitis and gestational pyelonephritis. It is believed that asymptomatic bacteriuria is also associated with complications of pregnancy and childbirth: premature birth, preeclampsia, antenatal fetal death, malnutrition of the newborn. BD can prevent the development of superinfection with virulent uropathogens; therefore, treatment with BD should be carried out only if there is proven benefit for the patient in order to eliminate the risk of selection of resistant and eradication of potentially protective strains of microorganisms [2].

Purpose of the study: to study the effect of asymptomatic bacteriuria on the occurrence of complications of pregnancy and childbirth.

Materials and methods. Outpatient records of 328 pregnant women for 2021 were studied at the antenatal clinic of the Regional Clinical Hospital No. 2 in Orenburg. The study included the results of general and bacteriological urine analysis during the diagnosis of asymptomatic bacteriuria and after treatment. Subsequently, we studied the course of pregnancy of this group of patients, the number of complications during pregnancy and childbirth. The study was conducted using statistical analysis.

Research results. True bacteriuria was detected in 21 (6.4%) women. The species composition of the selected flora is presented as follows in Fig. 1:

Rice. 1.

This graph shows that representatives of the Enterobacteriaceae family were most often sown (68.2%), among which the predominant species was (53.6%). Microorganisms of the genera Proteus and Klebsiella were isolated much less frequently (31.8%). In terms of age, the bulk were women aged 21 to 30 years. Women with second and third pregnancies predominated (87.2%), as shown in Fig. 2.

Rice. 2.

No clinical symptoms were detected in any of the pregnant women. In all of them, bacteriuria was detected in the first half of pregnancy. Predisposing factors for carriage of a dormant urinary tract infection, identified from anamnesis, are presented in Fig. 3.

Rice. 3.

From this diagram it follows that diseases of the upper respiratory tract accounted for 45.3%, kidney diseases suffered in childhood - 36.6%, complicated gynecological history affected 17.1% of cases. Complications of this pregnancy in 45.3% were preeclampsia. A significant level of threat of premature birth was also revealed - 25.7%. In 20.2%, the birth was complicated - bleeding, premature birth.

Conclusions. Thus, it has been established that the most common cause of asymptomatic bacteriuria is a previous infection or a focus of chronic infection in the body of a pregnant woman, and there is definitely a relationship between asymptomatic bacteriuria and the occurrence of complications of pregnancy and childbirth. Therefore, it is necessary to carry out the prevention of infectious diseases in pregnant women, timely diagnosis, especially in women with a history of diseases of the genitourinary organs, and when asymptomatic bacteriuria is established, begin high-quality antibiotic therapy, since antibacterial therapy significantly reduces the number of clinical episodes of UTI compared with placebo or no treatment [ 2]. Treatment of BB in pregnant women leads to a reduction in the risk of preterm birth or low birth weight babies.

Literature:

1. A. V. Zaitsev, T. S. Perepanova, M. Yu. Gvozdev, O. A. Arefieva. Urinary tract infections. Part 1. Moscow. — 2021. — pp. 9, 10.
2. Arkhipov E. V., Sigitova O. N., Morokov V. S., Kamasheva G. R. Urinary tract infections in children, adults, pregnant women: cystitis, pyelonephritis, asymptomatic bacteriuria: clinical recommendations. Moscow, Kazan, Rostov-on-Don.-2014.-S. 6.