Host parasite interaction in urinary tract infection

Lacticaseibacillus rhamnosus GR-1, a.k.a. Lactobacillus rhamnosus GR-1: Past and Future Perspectives

Lacticaseibacillus rhamnosus GR-1 (LGR-1) (previously classified as Lactobacillus rhamnosus GR-1) is the most researched probiotic strain for women's health. Its various urogenital health effects, including a reduction in the recurrence of bacterial vaginosis and urinary-tract infection, are well documented. The strain has also been safely used by HIV-positive subjects, a portion of whom have reported reduced diarrhea and increased CD4 counts. Unlike most probiotic strains used for urogenital health, LGR-1 has been extensively studied for its properties, including its genomic and metabolic traits and its surface properties. This review aims to highlight the totality of research performed with LGR-1, to act as a rigorous scientific benchmark for probiotic microbes, especially for application to women's health.

The innate immune response during urinary tract infection and pyelonephritis

Despite its proximity to the fecal flora, the urinary tract is considered sterile. The precise mechanisms by which the urinary tract maintains sterility are not well understood. Host immune responses are critically important in the antimicrobial defense of the urinary tract. During recent years, considerable advances have been made in our understanding of the mechanisms underlying immune homeostasis of the kidney and urinary tract. Dysfunctions in these immune mechanisms may result in acute disease, tissue destruction and overwhelming infection. The objective of this review is to provide an overview of the innate immune response in the urinary tract in response to microbial assault. In doing so, we focus on the role of antimicrobial peptides-a ubiquitous component of the innate immune response.

Idiopathic hypercalciuria associated with urinary tract infection in children

The aim of this study was to evaluate the association between idiopathic hypercalciuria (IH) and urinary tract infection (UTI) in children. This prospective clinical study included 75 patients with UTI (without urinary tract malformations and lithiasis) and a control group of 30 healthy children. Of the total number of patients with UTI, 21% (n = 16/75) had IH, but only 7% (n = 2/30) with IH were reported in the control group (p < 0.05). Recurrent UTI affected 33% (n = 25/75) of patients , and in 67% (n = 50/75) of patients, UTI was diagnosed for the first time. In the group of patients with recurrent UTI, 44% (n = 11/25) had IH, but only 10% (n = 5/50) were reported in the group of patients with first-time UTI (p < 0.05). The results of multifactorial logistic regression analysis showed that clinical and laboratory parameters (recurrent UTI, dysuria, and microscopic hematuria) may predict the diagnosis of IH in 80% of patients and absence of IH in 87% of cases. In our opinion, IH is a major contributing factor to UTI, especially to recurrent UTI in children.

Urinary tract infection caused by Haemophilus influenzae and Haemophilus parainfluenzae in children

There are few reports on urinary tract infections caused by Haemophilus influenzae or Haemophilus parainfluenzae in children. The true incidence is not known, since bacteria of Haemophilus species do not grow in standard urine culture media. With the objective of investigating the occurrence and character of urinary tract infections (UTIs) caused by Haemophilus bacteria in children, we searched the files of our UTI clinic. Over a 24-year period 36 children with Haemophilus spp. bacteriuria were identified out of a total of more than 5,000 UTI episodes. There was a significant gender difference in that Haemophilus influenzae dominated in girls and Haemophilus parainfluenzae in boys. With one exception, all children had important urinary tract abnormalities, such as malformation, gross reflux or bladder dysfunction. Permanent renal damage was seen in 25. We conclude that growth of Haemophilus bacteria in urine is associated with serious urinary tract abnormalities. The inability of bacteria of the Haemophilus species to grow in standard media commonly used for culture of uropathogens suggests that the true frequency of these strains as a cause of urinary tract infections is underestimated.

[Curative treatment of lower urinary tract infections]

Because it is limited to the bladder, infection of the lower urinary tract does not lead to renal scaring. It may be symptomatic or asymptomatic. When symptomatic it never includes high fever and general symptoms. Only symptomatic infections need treatment using oral antimicrobial monotherapy for 5 to 7 days. It is necessary to search for a predisposing factor--mainly bladder dysfunction and constipation.

Host defense within the urinary tract. I. Bacterial adhesion initiates an uroepithelial defense mechanism

Uroepithelial defense has ben suggested to contribute to the local host resistance against ascending urinary tract infection. The cellular mechanism, however, is not known. In this study, bacterial growth was measured under the direct and indirect influence of uroepithelial cells. To study if a specific ligand-receptor interaction is required for uroepithelial cell (UEC) activation, isogenic Escherichia coli mutants expressing either mannose-sensitive, mannose-resistant (p), or mannose resistant (s) pili were tested for their capacity to induce the UEC defense mechanism. The antibacterial effect of UEC was abolished either by performing coculture in chambers with a fluid-permeable membrane which separates UEC from bacteria or by inhibiting membrane contact using the antiadherence factor pentosane polysulfate. No difference between the various types of pili could be shown. All E. coli strains adhered comparably to the UEC and were subsequently suppressed in their growth. Even a "naked" mutant without expression of common pili showed a similar behavior. In conclusion, bacterial growth suppression depends on direct contact between the UEC and bacteria, but is independent of common pili expressed on E. coli.

Urinary tract infections. Old and new concepts

The recommendations for evaluation and management of pediatric patients with UTIs are summarized in Table 5. These recommendations were designed to minimize the risk of kidney damage in children with UTIs based on current perceptions of the pathogenesis of renal injury. The children at greatest risk for kidney damage are the infants and young children with febrile UTIs in whom effective treatment is delayed, those with gross VUR, and those with anatomic or neurogenic urinary tract obstruction. These recommendations likely will be modified as more is learned about the pathogenesis of renal injury associated with UTIs, as new therapeutic approaches are developed, and as imaging technology improves.

Management of primary vesico-ureteric reflux in children--operation ineffective in preventing progressive renal damage

Four studies comprising 606 children and with a follow-up of 4-5 years have shown that operation and long-term antibiotic prophylaxis are equally ineffective in preventing post-infectious, progressive renal damage in children with grade III-IV reflux. To consider only the grade of reflux in the choice of management is too simple an approach. Other aspects of the complex biology of UTI should also be considered. Another important aspect concerns the organization of the care. Efficient and robust routines for a thorough follow-up and measures to guarantee immediate diagnosis and treatment of recurrent infections in children known to be at risk may be more important for the preservation of the kidneys than a stereotyped policy of operation or "endless" antibiotic prophylaxis. Specialized teams should be used as in the treatment of other long-term diseases. Parents should be educated and made active participants in the supervision of children at risk. Controlled multicentre studies are powerful scientific instruments, but appear to have too little impact on clinical practice. The responsibility of clinical scientists to make important results known and understood among those concerned is discussed from the ethical point of view.

Recent advances in the management of vesico-ureteric reflux

Recent studies have demonstrated that both congenital hypoplasia and acquired scarring are involved in the parenchymal lesions associated with reflux nephropathy. Medical therapy can prevent symptomatic infection. While there is no proof that either medical or antireflux surgery prevents acquired scarring, paradoxically there is evidence that surgery adds no benefit to medical therapy, and that the results of medical therapy and surgical therapy are similar in children with isolated severe reflux. The group at most severe risk of renal scarring is infants and the effects of medical and surgical therapy in preventing acquired renal injury in this group have not been sufficiently investigated. On the basis of this information it has been our practice to maintain urine sterility using continuous antibiotic prophylaxis throughout infancy and early childhood. Following the development of reliable urine toilet habit and the ability to collect midstream urine specimens, antibiotics are given according to the frequency of urine infection, and weekly testing of morning urine with nitrite strips at home is used for early detection of infection and prevention of symptomatic infection. Antireflux surgery is mandatory for those children with complicated VUR (such as urinary tract obstruction) and should otherwise be reserved for those having persistent breakthrough infections in infancy and early childhood.