Introduction
Urinary tract infections are the most common infections caused by bacterial flora seen in routine clinical practice and are responsible for significant morbidity and high expenses. Escherichia coli is the most predominant bacteria, causing almost 90 percent of the urinary tract infections acquired by the community and nosocomial. About 25 percent of the urinary tract infections recur within six months. This recurrence of infection does pose a major problem.
Studies have concluded that the recurrence of infection is mainly because of the reinfection with new strains. As per a study, 77 percent of cases showed that reinfection was caused by relapse caused by previous primary Escherichia coli. Escherichia coli can replicate in the murine bladder and form biofilm-like bacterial colonies intercellularly. This acts as quiescent reservoirs that may remain stable for recurrent urinary tract infections. These colonies have not been studied so far in humans. On microscopical examination, women suffering from cystitis have been reported to have these bacterial colonies.
How Many Types of Escherichia Coli Are Present?
Based on PCR, there are four groups of Escherichia coli: group A1, B1 and B2. Also, group D. Group B2 Escherchia coli is the most common type among all the groups of Escherchia coli. Others follow it in order of group of gropu D, group A, and group B1. The reinfection of the urinary tract is most commonly seen with group B2. The primary infection is usually caused by group D.
Group B2 type Escherichia coli is usually susceptible to most antibiotics or antimicrobials. In contrast, group A is associated with resistance to most antimicrobials and is multidrug-resistant. Group D are multidrug resistant strains.
What Is the Clinical Presentation for Urinary Tract Infection?
Urinary tract infection is the presence of significant organisms in the urinary system. The load of the bacteria depends on the symptoms, category, number of isolated species, methods used to collect the specimen, and gender of the patient.
There are usually three clinical presentations of the urinary tract infection in general. Cystitis, asymptomatic bacteriuria, and acute pyelonephritis.
Asymptomatic bacteriuria is a condition in which bacteria are present in urine, but the patient presents without any symptoms. The complications associated with asymptomatic urinary tract infection depend on the population. For most patients suffering from this condition, the treatment is not beneficial. In pregnant women, asymptomatic urinary tract infection has adverse effects, and in these cases, screening and treatment for the disease are considered beneficial.
Cystitis is a condition that is associated with dysuria, urinatal urgency, and frequent urination. Sometimes, suprapubic pain is also associated with cystitis. This condition is seen to have short-term morbidity and is considered a benign condition that has a minimum sequel in the long term.
Pyelonephritis is a condition that is characterized by flank pain, nausea and vomiting, and fever, and this condition may also occur in the absence of cystitis. This condition may progress to bacteremia with morbidity and mortality, and also the long-term sequelae of this condition lead to renal scarring and impaired kidney function. In recurrent urinary tract infections, the patient reported three episodes of urinary tract infection in the previous 12 months.
What Is the Common Etiology of Urinary Tract Infection?
The most common bacteria leading to UTI is Escherichia coli. E. coli is a diverse bacterial species found naturally in the intestines of all humans. Escherichia coli is present in the colon's mucus layer and competes with facultative anaerobic bacteria in the intestine. Escherichia coli is classified based on certain somatic, polysaccharide, and flagella antigens.
The persistent Escherichia coli responsible for relapse are associated with type B2 Escherichia coli. The recurrence of urinary tract infection is caused by a relapse in previously present bacteria and the gene related to biofilm. Some genes associated with recurrence could be targeted for preventing and treating urinary text infections.
Adherence of bacteria contributes to virulence by enhancing colonization and facilitating interactions between bacteria, cells of the host, and matrix.
What Is the Treatment for Urinary Tract Infection?
The aim of treating urinary tract infections includes resolving the symptoms and also sterilization of the urine. The curing rate of urinary tract infection symptoms is around 25 percent within fice to seven weeks. 80 percent of urinary tract infection cases are treated spontaneously within five months, even if left untreated. The use of antimicrobials acts superior to placebo regarding success in microbiology, mostly in women suffering from uncomplicated cystitis.
While choosing the drug for treatment, several factors are considered, such as antimicrobial spectrum, internal dosing, effective drug at the specific urinary pH, effects of the specific drug on facial flora, undesirable side effects, and the cost of treatment.
Sulfamethoxazole and Trimethoprim, beta-lactams, Fluoroquinolones, and Nitrofurantoin are the most commonly prescribed drugs for urinary tract infections. The treatment is complicated with increasing antimicrobial résistance.
Usually, the first line of treatment for urinary tract infections in some countries is Sulfamethoxazole which is prescribed as a short-term regimen of three days. The increasing resistance to this drug is of concern as it is the first line of treatment for urinary tract infections. Mecillinam resistance has not increased more than 4 percent.
Conclusion
Urinary tract infection is a common disease. The relapse is usually caused primarily by infection of Escherichia coli. E. coli has a higher biofilm-causing capacity that could lead to relapse and recurrence of the infection. It has a higher virulent score and higher chances of causing hemolysis. A three-day course of pivmecillinam is the first line of treatment. The contribution of the host is also important. Identifying the body receptors and the mechanism of adhering to the cell and invasion of host cells may lead to developing new therapeutic drugs with better efficacy. The host defense mechanism should also be considered.
