Lower Tract Infections Research Articles

Urinary Tract Infections in Childhood: An Update

Although controversies remain regarding the definition, diagnosis, and management of urinary tract infections, such infections can pose a major risk to a child's well-being. Bacteriuria or recurrent urinary tract infections often pose difficult management problems. Symptomatic and asymptomatic bacteriuria during infancy are generally characterized by a benign outcome. In some children repeated episodes and, possibly, renal scarring result. The prognosis in young boys may be guarded if neonatal bacteriuria, with or without symptoms, occurs in the presence of anatomic defects. Although a variety of pathogens have been identified as causing urinary tract infections, Enterobacteriaceae are usually the cause of initial uncomplicated lower tract infections. Accepted therapy for such infections is reviewed, as are the combination therapies used for hospitalized patients with upper tract infections. An investigation of piperacillin, a new, extended-spectrum acylaminopenicillin, raises the hope that it may provide effective monotherapy for upper tract infections. The criteria for selecting patients who require radiologic evaluation in the management of urinary tract infections are reviewed.

Urinary Tract Infections and the Urethral Syndrome in Adult Women: Pathogenesis, Diagnosis, and Therapy

Urinary infections in adult women are extremely common. Yet, dysuria, often a symptom of these infections, can be caused by a number of genitourinary pathogens. Symptomatic urinary infections caused primarily by Escherichia coli or Staphylococcus saprophyticus are best confirmed by demonstrating the presence of 10(2) or more organisms per ml of midstream urine in quantitative cultures. Other causes of dysuria such as vaginitis and urethritis due to venereal disease should be suspected in patients with additional signs and symptoms characteristic of these infections and in young, sexually active females. Effective treatment of urinary infections is achieved with a number of antibiotics; the length of therapy is determined by the location of infection in the urinary tract. Although equal in efficacy to conventional therapy for uncomplicated lower tract infections, single-dose therapy of dysuric women should be limited to patients for whom adequate follow-up can be insured.

Single-dose antibiotic therapy of urinary tract infection: Is it appropriate in the emergency department?

Accurate diagnosis of urinary tract infection (UTI) is possible in the emergency department. Clinical differentiation of upper tract infection (pyelonephritis) from lower tract infection (cystitis) is difficult. The consequences of untreated UTI justify treatment by the emergency physician. Many treatment schemes are available. Single-dose antibiotic therapy is the preferred treatment method for uncomplicated UTI. It reduces compliance problems, effectively cures lower UTI, and provides for early identification of patients with more complex infection. The complications of this therapy are minimal.

URINARY LDH IN URINARY TRACT INFECTIDNS

Three published reports show increased activity of the slow moving LDH isoenzymes in the urine of children with upper urinary tract infections. We studied urinary LDH enzyme activity during 88 urinary tract infections in girls in whom the site of infection was localized using the bladder washout test (BWO).These data do not distinguish patients with upper tract from those with lower tract infections. We also compared urinary LDH activity in girls with BWO confirmed clinical cystitis with those with BWO confirmed clinical pyelonephritis.There were no significant differences in LDH activity between these two groups of patients.

N-Acetyl-β- d-glucosaminidase (NAG) and NAG isoenzymes in children with upper and lower urinary tract infections

The use of N-acetyl-β- d-glucosaminidase (NAG) to diagnose the site of urinary tract infection was studied in pediatric patients. Differentiation between upper and lower tract infections (UTI) was based on clinical grounds and on elevated erythrocyte sedimentation rate, C-reactive protein and fever. NAG excretion expressed as nmol · h −1 · mg − of urinary creatinine was higher in children with upper UTI (mean ± SE 906 ± 236) than in those with lower UTI (145 ± 23) or healthy children (151.6 ± 10) ( p<0.01 by Duncan's test). In children with upper UTI, NAG excretion fell in parallel with the remission due to antibiotic treatment. This however was not seen in children treated with aminoglycosides. A specific and significant elevation ( p < 0.01) of the B isoenzyme of NAG was documented in children with upper UTI but not in those with lower UTI (B form in upper UTI 49.2% ± 3.9 versus 21.9 ± 3.3 in lower UTI; healthy children 18.9 ± 3.4). The percentage of B isoenzyme excreted was high in two children with upper UTI but was low total NAG urinary excretion, suggesting that the quantification of isoenzymes offers further specificity in diagnosis. We conclude that the measurement of NAG and its isoenzymes in children with UTI provides useful information in the diagnosis of the site of infection.

1505 LOCALIZATION OF THE SITE OF URINARY TRACT INFECTIONS USING SERUM C-REACTIVE PROTEIN (CRP)

The CRP test has been used as an indication of the presence or absence of kidney inflammation during urinary tract infections. However, only Jodal's group has reported a study of this application. In our studies the concentration of serum CRP, measured by radial immunodiffusion, are compared with the site of infection determined by bladder washout (BWO) and by clinical criteria. The table shows that 9 of 16 children with upper tract infection by BWO had serum CRP levels >25 μg/ml while only 4 of 28 with lower tract infection had values in this range. Four of 6 children with upper tract infection by BWO and clinical acute pyelonephritis had serum CRP levels >25 μg/ml. However, the CRP levels were <25 μg/ml in 5 of 7 children with upper tract infections by BWO and clinical diagnoses of cystitis or asymptomatic bacteriuria. This suggests that the CRP test may be unreliable for localization of the site of infection in the clinical situation in which this information is most needed.

Trimethoprim-rifampin, a new combination agent: efficacy in localized urinary infection and influence on microflora

Twenty women with recurrent or persistent urinary tract infections were treated with a fixed combination of trimethoprim-rifampin (TMP-RAM). The site of infection was established by the antibody-coated bacteria test. Sixteen women had upper tract infections (antibody-coated bacteria tests positive); eight were cured, three failed, and five relapsed. All four women with lower tract infections (antibody-coated bacteria tests negative) were cured. Three of five patients with structural abnormalities failed. The 12 cures and 5 relapses were associated with organisms susceptible to either TMP (minimal inhibitory concentration, less than or = to 7 micrograms/ml) or RAM (minimal inhibitory concentration, less than or = to 32 micrograms/ml). In contrast, two of the three failures were associated with organisms resistant to both TMP and RAM. In one patient, RAM resistance emerged during treatment. During therapy, urinary strains were eradicated from the periurethral and anal-canal areas in all but 3 fo 16 patients. Adverse reactions, noted in 16 women, included nausea (10), dizziness (6), headaches (2), rash (1), an blurred vision (1). Antimicrobial susceptibility data on 246 isolated from urinary, periurethral, and anal-canal specimens are included. Our findings suggest that TMP-RAM is effective in urinary infections and may prevent the emergence of RAM-resistant strains.

20 URINARY TRACT INFECTION CAUSED BY STAPHYLOCOCCUS SAPROPHYTICUS (SS)

In 492 college coeds, with acute, uncomplicated UTIs, documented by >105 colonies per ml. of the same bacteria in 2 or 3 consecutive urine cultures, E. coli and novobiocin resistant (SS) comprised 76.0% and 13.0% of the urinary pathogens, respectively, and other bacteria 11.0%. The in-vitro sensitivity testing revealed that SS were 100% sensitive to trimethoprim, trimethoprim/sulfamethoxozole, nitrofurantoin, and cephalexin; 91.0% to ampicillin; 93.0% to sulfasoxozole and 0.0% to nalidixic acid. Patients with either E. coli or SS organism presented with similar symptoms of an acute lower tract infection. Costovertebral angle tenderness was noted in 21.0% of the patients with SS and in 10.0% of those with E. coli. Fever >99.5C. was present in 15.0% of patients with SS and in 25.0% of those with E. coli. Clinical response to therapy was similar for both groups. Isolation of SS from the periurethral (52.0%), vaginal (31.0%), and rectal (11.5%) areas could only be accomplished in patients who had this organism as the primary urinary pathogen. SS was the second most common urinary pathogen isolated after E. coli in young women.

Uropathogenic properties of Escherichia coli in recurrent urinary-tract infection.

Properties of Escherichia coli considered to be important in the pathogenesis of urinary-tract infection were investigated. The following properties were more common in E. coli strains isolated from urinary infections than in periurethral strains from healthy individuals: (i) O serogroups 2, 4, 6, 8, 18ab and 75; (ii) high K-antigen titre; (iii) production of haemolysin; (iv) production of fimbriae; (v) fermentation of salicin. The correlation between isolation of a strain from the urinary tract and possession of any single property was not strong; however, strains rich in a combination of these pathogenic properties were rarely isolated from the periurethral area of healthy subjects but were common in urinary infections. Nevertheless, a significant proportion of urinary strains had few pathogenic properties. Strains rich in pathogenic properties were more commonly isolated from upper urinary-tract infections than from lower-tract infections; this indicates that the properties of the invading organism may influence the localisation of infection.

Comparison of Urinary Lactic Dehydrogenase with Antibody-Coated Bacteria in the Urine Sediment as Means of Localizing the Site of Urinary Tract Infection

Two noninvasive methods of localizing the site of urinary tract infection, urinary lactic dehydrogenase (LDH) isoenzymes and antibody coating of bacteria in the urinary sediment, have been prospectively compared with the bladder washout technique in a series of children with urinary tract infection. Fifteen children had infection localized in the upper tract. Urinary LDH isoenzymes correctly localized the infection in 14 children; however, the infection was correctly localized by the antibody coating of bacteria in only eight patients (P less than .02). Fourteen children had lower tract infection by the bladder washout technique. Urinary LDH isoenzymes localized the infection in all 14 children, whereas the antibody coating correctly localized the infection in ten children (P less than .05). This study shows the urinary LDH isoenzyme pattern to be a more accurate technique than the detection of antibody-coated bacteria for localizing the site of urinary tract infection.

Urinary Tract Infection Localization in Women

The site of urinary infection in 51 adult women was determined by the bladder-washout technique (BW). Of the 37 patients with proved upper-tract infection shown by BW, 16 had upper-tract symptoms, three had lower-tract symptoms, and 18 were asymptomatic; 31 had antibody-coated bacteria (ACB), and six had no ACB. Of 14 patients with proved lower-tract infection shown by BW, three had upper-tract symptoms, five had lower-tract symptoms, and six were asymptomatic; none had ACB. All 31 women whose infecting bacteria were coated with antibody proved to have an upper-tract infection shown by BW. A subset of the population of adult women with upper-tract infection have organisms emanating from their ureters at BW localization, which are not coated with antibody. Physicians must be cautious in interpreting results that are negative for ACB.

Factors related to host recognition of bacterial antigens which cause urinary infection

Some gram-negative bacteria isolated from the urinary tract have on their surfaces antigens identical to or similar to those of human blood groups A, B, or (H) O. Human isoantibodies to these antigens appear to play some part in the immunologic response to urinary infections. It is postulated from this observation that human isoantibodies A and B persist because they are important segments in resistance to infections rather than reactions to other human tissues (as in transfusions or transplantation). To further assess the relationship between bacterial antigens similar to those of blood groups A or B and host isoantibody response we performed an in-depth study of this relationship in 13 patients with urinary infection of upper or lower tracts. Isoantibody of the immunoglobulin M class appeared to be the antibody which reacted with both bacteria and human erythrocytes. Patients with infections of the upper tracts had proportionately more cross-reacting anti-B antibody than those with lower tract infections, but the amounts of anti-A antibody were roughly equivalent in both types of infection. Response of a given host was genetically pre-determined. Some deficiency in host recognition of bacterial antigens was noted since only 4 of 13 patients recognized bacterial A or B antigens while all normals did so. Study of the defined cross-reactions between bacterial and blood group antigens offers further opportunities for definition of the genetic components of immunity to urinary infections.

Coccidoidouria: clinical significance.

Twelve patients had urine cultures positive for Coccidioides immitis. Ten patients showed the usual criteria for dissemination, but 2 were believed, before urine culture, to have only chronic pulmonary involvement. In 8 patients, there was impairment of host defense mechanisms due either to associated disease or immunosuppressive drug therapy. Only 2 of 11 patients tested reacted to coccidioidin skin-test antigen. Colony counts of C. immitis in the first voided morning urine spacimens ranged from 0.03/ml to 17/ml. With prostatic involvement, colony counts in the expressed secretions ranged from 15/ml to 120/ml. The site of urinary tract coccidioidomycosis, which could be adduced in 9 patients, was the upper tract in 1, lower tract in 6, and in both upper and lower tracts in 2. In patients with lower tract infection, the prostate was involved in 4 and the epididymis in 2.

Efficacy of Trimethoprim-Sulfamethoxazole in Bacteriuria

Sixty-three patients with bacteriuria were treated in a randomized double-blind study with the combination of trimethoprim and sulfamethoxazole (TMP-SMZ) or SMZ alone. Twenty-one of 32 patients treated with TMP-SMZ were cured by the time of followup compared with 14 of 31 treated with SMZ alone. Of the 26 patients infected with sulfonamide-resistant organisms, the combination cured 11 of 15, whereas SMZ alone cured three of 11. Thirty-five females had upper urinary tract infection. TMP-SMZ cured 12 of 18, and SMZ alone cured six of 17. An additional 48 patients with 50 episodes of infection were treated with the combination in an open-label study. Seventeen of 27 patients with upper tract infection were cured after two weeks of therapy. Therapy for seven days cured 12 of 14 episodes of asymptomatic or lower tract infection. Ten patients experienced side effects with the combination drug. There was no hematologic toxicity. In both studies, TMP-SMZ effectively eradicated sulfonamide-resistant pathogens, and a two week course of treatment cured two-thirds of females with upper tract infection.