Types and why are bacteria in urine dangerous?

Today, more and more often one hears the question of whether bacteria in urine are dangerous. Should they show up there? It turns out that urine is considered a conditionally sterile biological fluid, so normally it shouldn't contain bacteria. However, in fact, bacteria are often found in the urine. And this is already a sign of pathology, which can serve as an important diagnostic criterion, on the basis of which a particular diagnosis can be made.

Why are bacteria in urine dangerous?

Often patients ask the question: "Why are bacteria in urine dangerous ?" The main thing that the patient needs to know is that normally there are no bacteria in the urine. Therefore, their presence indicates inflammation and the development of an infectious process. This is dangerous because the infection progresses, and causes serious damage to the kidneys, the genitourinary system as a whole. Chronization of the inflammatory process is dangerous, as well as possible consequences and complications, for example, the formation of new foci of infection, or the penetration of infection into the reproductive system, the development of gynecological and urological diseases, which often lead to infertility, or problems during pregnancy and childbirth in women. [1]

Cylinders in urine and bacteria

If cylinders and bacteria are detected in a urine sample from a patient, this may indicate the development of pathology from the urinary system, kidneys. So, first of all, you need to know exactly how many bacteria have been identified, and which ones (species and genus). It is also important to determine the type of cylinders, since different types of cylinders indicate a different type of pathology. Normally, the cylinders are absent; in the case of pathology, they are detected during the microscopic examination of the urinary sediment. Most often, the cylinders are derivatives of the cellular or protein structures of the body, and appear in the urine as a result of the destruction of these structures.

For example, the identification of hyaluronic cylinders may indicate kidney pathology, the decomposition of protein components as a result of intoxication, exposure to high temperatures (prolonged fever, a sharp jump in body temperature). It is often observed against the background of pregnancy, poisoning, severe infectious diseases, with nephropathy and renal failure. [2]

Waxy casts are mainly represented by erythrocyte mass and appear when blood elements enter the human urine. For example, they can be a sign of kidney rejection, anemia, erythrocyte damage, amyloidosis, in many chronic kidney pathologies and impaired renal circulation.

The appearance of erythrocyte casts indicates open renal bleeding. The waxy and erythrocytic casts are similar to each other, it is important to accurately differentiate them.

Epithelial and leukocyte casts indicate the development of an inflammatory process, a powerful epithelialization, less often they are a sign of poisoning with heavy metal salts.

Granular cylinders are an unfavorable phenomenon. They can be a sign of nephrotic syndrome, decay of cellular and tissue structures, indicate severe degenerative processes, renal failure. They often indicate the irreversibility of processes. [3]

Bacteria and urates in urine

The detection of bacteria and urates in human urine may indicate acidification of urine, that is, urine becomes acidic. This means that it contains a large amount of acidic salts. This is often observed at high temperatures, or prolonged fever, with temperature changes from critically low to high values, with various infectious diseases that affect the kidneys, and are also accompanied by hyperthermia. Often urates appear with gout, hypovolemia, which is accompanied by diarrhea and vomiting. May be a sign of dehydration, severe dehydration of the body. Also, urates are no less often found with extensive thermal burns, in situations in which thermoregulation is significantly impaired, the protective and excretory function of the skin decreases. Urates can be diagnosed in urine after intensive radiation or cytostatic therapy, which takes place in the treatment of leukemia, malignant neoplasms. [4]

Urates are small pigmented grains that most often take on a red, brick hue, and stain the urine the corresponding color. In this case, the formation of an acidic environment occurs. Accordingly, the microflora changes sharply - representatives of the normal environment die, the number of acidophilic bacteria increases sharply, that is, bacteria that live in an acidic environment and consume acids as a nutrient substrate. This contributes to the additional development of inflammatory processes, irritation of the mucous membranes, dysbiosis appears.

Types of bacteria in urine

First of all, you need to understand that normally there is not a single type of bacteria that could be found in urine. When it comes to pathology, a fairly wide variety of bacterial species can be detected in the urine.

It is important to distinguish between the nature of the microbiocenosis. All types of bacteria in urine can be conditionally divided into three subgroups - transient, resident and obligate microflora. Transient microflora is bacteria that have entered the urine at random and are not permanent residents of the urinary tract. This may be microflora that was accidentally introduced from other foci of infection, which penetrated from other biotopes. The latter is especially common in women. For example, cases of vaginal microflora entering the urine due to the anatomical proximity of the genitourinary and reproductive systems. It also includes cases of infection from the external genital organs with poor toilet, cases of collection of urine in non-sterile containers. [5]

Usually, two factors indicate a transient microflora:

1. the types of bacteria that are not characteristic of the genitourinary system have been identified in the urine.
2. the number of microorganisms is insignificant (it can be one or several single colonies).

If a transient microflora is detected, or suspected of it, it is recommended to conduct a second study to confirm or refute the diagnosis.

Various types of fungal infection, including yeast-like fungi of the genus Candida, most often act as a transient microflora. These include Proteus vulgarus, Lactobacillus spp., Bifidobacterium spp., Various representatives of the vaginal, cervical, urethral microflora, causative agents of sexually transmitted diseases, less often tetanus causative agents, soil microorganisms, various types of anaerobic infections.

The resident microflora is represented by those microorganisms that normally inhabit the genitourinary tract. These are various representatives of normal human microflora. It is advisable to talk about conditionally pathogenic microorganisms, since normally (with an optimal amount not exceeding the norm), these microorganisms perform protective functions, preventing the development of diseases of the genitourinary tract. This is achieved due to the colonization resistance of the mucous membranes, which occurs as a result of the functioning of opportunistic microflora. The presence of normal microflora does not allow the penetration of pathogenic microflora, therefore, protects against various diseases.

However, under certain conditions, conditionally pathogenic and normal microflora itself can cause disease, since its number increases sharply. This situation can occur with reduced immunity, after a recent antibiotic therapy, after chemotherapy, radiation therapy, against the background of immunodeficiencies of varying severity, with dysbiosis and dysbiosis. The resident microflora includes various types of staphylococci, streptococci, Escherichia coli, enterococci, Klebsiels, various types of bacilli, vibrios. Most often it is a gram-positive aerobic microflora. When detecting transient microflora, the diagnostic value is not so much its qualitative characteristics as quantitative indicators. [6]

Obligate microflora is represented by pathogenic microorganisms, which normally should not be in the human body. And primarily in the genitourinary system. These are all causative agents of inflammatory and infectious diseases, bacteremia, sepsis. This includes a wide variety of gram-negative and gram-positive microorganisms, which can be both aerobic and anaerobic. Often there are acidophilic microorganisms that live with increased acidity of urine. It can be various types of genitourinary, venereal infections, representatives of the intestinal group, mycobacteria, urobacteria, chlamydia, rickettsia, prions, spitochetes, and even tuberculosis bacteria.

E. Coli bacteria in urine

E. Coli bacteria are not normally found in urine. Escheriсhia coli is nothing more than Escherichia coli, which is normally a representative of the normal intestinal microflora. In urine, it can occur in some inflammatory and infectious processes. The penetration of E. Coli into biotopes unusual for it, for example, in the urogenital tract, causes an inflammatory process in it. Therefore, it is important to quantify. The higher the degree of bacterial contamination, the more severe the inflammatory process. If more than 10 ⁴  CFU / ml are detected, antibiotic therapy is required. [7]

E. Coli bacteria can also get into the urine accidentally, for example, when the toilet is bad when stool gets into the urine, or when urine is collected in contaminated dishes (transient microflora). But in this case, isolated microorganisms are detected. A large number of these bacteria often indicates a pathological process and requires treatment. If single colonies of microorganisms are detected, the analysis must be repeated again. [8], [9]

Klebsiella bacteria in urine

Depending on the exact type of bacteria of the genus klebsiella identified in the urine, it is possible to determine the exact source of the penetration of this bacterium into the body. Often, klebsiella is a representative of the normal microflora of the urogenital tract, intestines or respiratory system. Detection of more than 10 ⁴  CFU / ml indicates the development of an intense inflammatory and infectious process. The risk of developing bacteremia and sepsis sharply increases. In most cases, antibiotic therapy is required.

Bacteria of the genus klebsiella in urine can be found mainly in pathologies of the kidneys, bladder, cystitis, pyelonephritis, and other inflammatory processes, as well as with reduced immunity, after undergoing antibiotic therapy, treatment with uroseptics, after operations on the genitourinary system, after many infectious diseases, and even colds.

Proteus bacteria in urine

The detection of Proteus bacteria in the urine may indicate an inflammatory process. Proteus is a normal representative of the urogenital microflora. Normally, no more than 10 ³  CFU / ml is found in the genitourinary system (on the mucous membranes). An excess of these parameters indicates the development of inflammation, as well as a decrease in the protective and compensatory mechanisms of the mucous membranes. A similar situation is often observed with dysbiosis, as well as in women with gynecological diseases. Failure to observe personal hygiene, especially in women during menstruation, can lead to an increase in the number of these microorganisms. Exceeding the norm requires antibiotic therapy. [10], [11]

P. Mirabilis is capable of causing symptomatic urinary tract infections, including cystitis and pyelonephritis, and is present in cases of asymptomatic bacteriuria, especially in the elderly and patients with type 2 diabetes. [12],  [13]These infections s can also cause bacteremia and progress to potentially life-threatening urosepsis. In addition, infections with P. Mirabilis can cause the formation of urinary stones (urolithiasis).

P. Mirabilis is often isolated from the gastrointestinal tract, although the question of whether it is a commensal, pathogen, or transient is somewhat controversial. Most urinary tract infections (UTIs) of P. Mirabilis are thought to result from the spread of bacteria from the gastrointestinal tract, while others result from person-to-person transmission, especially in healthcare settings. [14]This is supported by evidence that some P. Mirabilis patients have UTIs with the same P. Mirabilis strain in their stools, while others do not have P. Mirabilis in their stools. [15]In addition to urinary tract infection, this species can also cause infections of the respiratory tract, eyes, ears, nose, skin, throat, burns and wounds, and has also been associated with neonatal meningoencephalitis, empyema, and osteomyelitis. [16]Several studies have linked P. Mirabilis to rheumatoid arthritis, although others have failed to find a link (see reviews in  [17] and out [18]). It is believed that antibodies against the enzymes hemolysin and urease are subsequently able to recognize autoantigens targeting patients with rheumatoid arthritis.

Cocci bacteria in urine

Cocci bacteria can be detected in the urine, which is considered a sign of pathology, since urine should normally be sterile. Cocci mean any bacteria that have a rounded shape (staphylococci, streptococci, enterococci, pneumococci, and others). The appearance of cocci, like any other bacteria in the urine, means only one thing - the development of a pathological process in the body. First of all, it means the inflammatory process, which is accompanied by the development of a bacterial infection. [19]

When detecting cocci, it is important to identify them (determine the exact name of the type of microorganism), and determine quantitative indicators. Knowing how many cocci are found in the urine, one can judge the severity of the infectious process, draw conclusions and predictions, and select the appropriate treatment. [20]

It is impossible to unequivocally answer the question of what caused the appearance of cocci bacteria in the urine (at least, without an accurate comprehensive diagnosis). This is due to the fact that there is a fairly wide variety of these reasons. [21]

Enterococcus bacteria in urine

Enterococcus bacteria can be detected in urine. To be more precise, it should be said that representatives of the genus Enterococcus have been identified, since under this generic name a large number of related bacteria are united. Normally, they are representatives of the normal intestinal microflora, and when they enter the genitourinary system, they lead to the development of an infectious process. There may be several ways enterococci enter the urine. Most often this is an autoinfection or infection from external sources. Autoinfection should be understood as a focus of infection located in the body. An inflammatory and infectious process subsequently develops from it. It can be a chronic infection of the urinary tract, kidneys, reproductive system, latent, active or chronic genitourinary infections, sexually transmitted diseases. [22]

With an external source of infection, the infection enters the body from the external environment. It can get into the urine by accident, for example, with feces, if there is insufficient quality toilet before collecting urine for analysis. In women, the infection is often caused by the penetration of infection from the genitals (from the external genital organs, the infection rises up into the genitourinary system, and the main focus of infection is formed). In some cases, the identification of representatives of the intestinal microflora in the urine may indicate proctological diseases, and also be a sign of a rectovaginal fistula in women, in which the contents of the intestine enter the vagina and the genitourinary system. With a fistula, an opening (through fistula) is observed in the rectovaginal septum, which separates the intestine (rectum) from the vagina and urinary system. [23]

Bacteria in urine +, ++, +++

In the results of the analysis, it is necessary to determine not only the presence of the bacteria themselves in the urine, but also indicate their approximate number. The exact amount (a specific numerical value expressed in CFU / ml) can only be determined during a special bacteriological study, in which urine is cultured on special nutrient media, then the pathogen is isolated and identified. In the usual general (clinical analysis), only the conditional degree of bacteremia is indicated. So, in the urine, bacteria are denoted by the signs +, ++, +++. The + sign indicates an insignificant amount of bacteria in the urine. These can be isolated bacteria. The ++ sign indicates a moderate amount that exceeds the norm and may be a sign of infection. The +++ sign may indicate an intense inflammatory and infectious process in the genitourinary system, and requires additional diagnostics and mandatory treatment. Also, in some classifications, the ++++ sign is also distinguished, which indicates a severe infectious process, bacteremia, sepsis. [24]

Bacteria in urine in moderation

Despite the fact that the results of the analysis may contain a ++ sign, which indicates the presence of bacteria in the urine in a moderate amount, this formulation is incorrect and uninformative. This can only indicate the need for detailed diagnostics. It is necessary to conduct a bacteriological study, check the urine for sterility. In the course of these laboratory tests, the exact quantitative content of microorganisms in the urine will be revealed. It is also important to identify microorganisms, and to identify the exact species of the causative agent of the disease. This will allow you to select the appropriate treatment. 

Significant amount of bacteria in urine

If a significant amount of bacteria is detected in the urine (designation +++ or ++++ in the OAM results), additional diagnostics are necessary. In the course of additional diagnostics, it is necessary to determine the type of microorganism and its exact amount, expressed in CFU / ml. This is the basis for an accurate diagnosis and appropriate treatment. It is also important to take into account the current state of the patient, the clinical picture of the pathology, symptoms. If a significant amount of bacteria is found in the urine, the latent course of the pathology is almost completely excluded. A person will have pronounced symptoms of an inflammatory and infectious process. In more detail, the symptomatology depends on what kind of bacteria is found in the urine (different bacteria cause a different picture of pathology). 

Often, symptoms such as urinary disturbance, frequent or false urge to urinate, pain, stinging, burning, and discomfort are manifested. Increased pain is noted at night. With movement, the pain can increase dramatically.

Complications and consequences

The consequences, complications, can be very unfavorable. Bacteria in the urine always indicate the development of inflammation, an infectious process. The infection requires treatment; it never goes away on its own. If untreated, the risk of developing sepsis and bacteremia, as well as kidney failure, development of failure, cirrhosis, and necrosis, is quite high. Less dangerous consequences are the development of a chronic infection, which will be accompanied by periodic exacerbations, relapses, and can also cause various inflammations of the genitourinary system - from cystitis to nephritis, pyelonephritis, glomerulonephritis, nephropathies. [25]

No less dangerous is a latent infection, foci of infection that can migrate to other biotopes, like metastases in cancerous tumors. An incompletely cured urine infection can also cause reproductive pathologies, up to infertility, inability to conceive and bear a child. In women, an infection in the urine can cause abortion and miscarriage, premature birth, and even intrauterine infection of the fetus. Therefore, compulsory treatment is required, often even hospitalization in a specialized department. The sooner it is started, the more efficiently and faster the result will be achieved. It is important to start treatment in a timely manner.