Change of pathogeus and pathogen persistence in chronic urinary tract infections in childhood. E. coli-O-serotypes in follow-up

In 171 children with urinary tract infections, all strains of E. coli O isolated from the urine in the course of two years were serotyped. The serogroups 06, 02, 08 and 01 were predominant. Follow-up examinations revealed a 78% incidence of reinfection, while relapses (= identical E. coli serotypes or pathogen species) only occurred in 22% of all new episodes. Two thirds of all reinfections by E. coli occurred within two months of the previous E. coli infection.     

Alport syndrome with a peculiar pattern of distribution of the alpha3-alpha6 chains of type IV collagen in renal basement membrane

Chronic bacteriuria is a common occurrence among spinal-cord injury patients and others with neuropathic bladders. If bacteria are present in the urinary tract, the patient may develop symptoms of infection or remain asymptomatic. We have compared virulence properties of 28 Escherichia coli isolates from patients with symptomatic urinary tract infections (UTI) and 29 E. coli isolates from patients with asymptomatic bacteriuria (ABU). Bacteria from patients with symptomatic UTI were more likely to be hemolytic than isolates from patients with ABU (P = 0.05) or fecal isolates obtained from healthy volunteers (P < 0.001). Bacteria from patients with symptomatic UTI were also more likely than strains isolated from patients with ABU (P = 0.08) or fecal strains (P < 0.001) to exhibit D-mannose-resistant hemagglutination of human erythrocytes. The results suggest that E. coli isolates from nonimmunocompromised patients who require intermittent catheterization and who develop symptomatic UTI may be distinguished from bacteria recovered from patients who remain asymptomatic and possibly from normal fecal E. coli.     

Urodynamic factors influence the duration of Escherichia coli bacteriuria in deliberately colonized cases

PURPOSE: We evaluated the influence of urodynamic factors on the establishment of bacteriuria, after deliberate intravesical inoculation with Escherichia coli. MATERIALS AND METHODS: Nine women and 7 men with recurrent symptomatic urinary tract infections underwent intravesical injection of E. coli 83972. This strain had documented ability to persist in the urinary tract and it lacks expressed virulence factors associated with urinary tract infection. RESULTS: Successful long-term colonization (5 months to 3 years) was achieved in 6 of 12 patients with neurogenic bladder disorder, including normal or high bladder capacity, normal or low detrusor pressure and residual urine. Short-term bacteriuria (13 days) occurred in 1 but long-term bacteriuria was not established in the 4 patients with normal lower urinary tract function. Occasionally urine samples from the colonized patients contained other bacterial strains, which cleared spontaneously except for a Klebsiella strain that became established in 2 and subsequently eliminated E. coli 83972. CONCLUSIONS: E. coli 83972 bacteriuria could only be established in a subset of patients with defective bladder voiding, suggesting that urodynamic defects permit a nonvirulent strain to establish in the urinary tract, but that additional host factors determine if bacteriuria will persist.     

A cluster of Escherichia coli O157:H7 infections with the hemolytic-uremic syndrome and death in California. A mandate for improved surveillance

In mid-January 1993, an outbreak of Escherichia coli O157:H7 infections associated with eating hamburger patties at a fast-food restaurant chain (chain A) was reported in Washington State. From mid-December to mid-January, 9 cases of E coli O157:H7-associated bloody diarrhea and the hemolytic-uremic syndrome had been reported in San Diego County, California. A total of 34 persons had bloody diarrhea, the hemolytic-uremic syndrome, or E coli O157:H7 organisms isolated from stool during the period November 15, 1992, through January 31, 1993. Organisms of E coli O157:H7 identified from 6 persons were indistinguishable from those of the Washington outbreak strain. Illness was associated with eating at chain A restaurants in San Diego (odds ratio, 13; 95% confidence interval, 1.7, 99) and with eating regular-sized hamburgers (odds ratio, undefined; lower-limit 95% confidence interval, 1.3). Improved surveillance by mandating laboratory- and physician-based reporting of cases of E coli O157:H7 infection and the hemolytic-uremic syndrome might have alerted health officials to this outbreak sooner, which could have resulted in earlier investigation and the institution of measures to prevent more cases.     

Comparison of Escherichia coli strains recovered from human cystitis and pyelonephritis infections in transurethrally challenged mice

Urinary tract infection, most frequently caused by Escherichia coli, is one of the most common bacterial infections in humans. A vast amount of literature regarding the mechanisms through which E. coli induces pyelonephritis has accumulated. Although cystitis accounts for 95% of visits to physicians for symptoms of urinary tract infections, few in vivo studies have investigated possible differences between E. coli recovered from patients with clinical symptoms of cystitis and that from patients with symptoms of pyelonephritis. Epidemiological studies indicate that cystitis-associated strains appear to differ from pyelonephritis-associated strains in elaboration of some putative virulence factors. With transurethrally challenged mice we studied possible differences using three each of the most virulent pyelonephritis and cystitis E. coli strains in our collection. The results indicate that cystitis strains colonize the bladder more rapidly than do pyelonephritis strains, while the rates of kidney colonization are similar. Cystitis strains colonize the bladder in higher numbers, induce more pronounced histologic changes in the bladder, and are more rapidly eliminated from the mouse urinary tract than pyelonephritis strains. These results provide evidence that cystitis strains differ from pyelonephritis strains in this model, that this model is useful for the study of the uropathogenicity of cystitis strains, and that it would be unwise to use pyelonephritis strains to study putative virulence factors important in the development of cystitis.     

Epitopes of the P-fimbrial adhesin of E. coli cause different urinary tract infections

PURPOSE: This is a study of the interaction of the tip protein of P-fimbriae E. coli, its specific urothelial adhesin, and urothelial receptors for the adhesin. This tip protein has several epitopes that adhere to different isoreceptors containing the urothelial alpha-gal-1-4 beta-gal disaccharide. Renal tubular cells of our monkey model contain the globoside isoreceptor, and thus ureteral inoculation of E. coli with the class II tip protein leads to pyelonephritis. The class III tip protein adheres to the Forssman antigen and causes cystitis in humans. MATERIALS AND METHODS: An E. coli strain, DS17 which originally caused pyelonephritis in a child, is P-fimbriated and contains a class II tip adhesin. A mutant was produced to contain a class III tip adhesin. Eight monkeys had a ureteral inoculation of E. coli DS17 and 4 monkeys with E. coli DS17-1. In addition, we studied in vitro adherence by these strains. RESULTS: We show that in vitro adherence by the tip protein of P-fimbriae to bladder cells of the monkey occurs by several mechanisms, adhering to specific receptors for the class II and III epitopes of the tip protein as well as by means of type 1 fimbriae. In addition, the PapE protein of the fibrillum of the P-fimbriae adheres to fibronectin. As always, electrostatic and hydrophobic interaction remain important contributions to adherence. E. coli DS17 caused pyelonephritis, but DS17-1 caused cystitis. Bacteriuria was prolonged by DS17 infection. CONCLUSION: The site of a urinary tract infection from P-fimbriated E. coli can be predicted by the epitope of the tip protein of P-fimbriae.     

Modulation of P-fimbriation by ciprofloxacin in uropathogenic Escherichia coli

BACKGROUND: The aim of this study was to determine the effect of ciprofloxacin at subinhibitory concentrations on the expression of P fimbriae of uropathogenic Escherichia coli. Thirty-nine strains of Escherichia coli isolated from out patients with urinary tract infection were studied. Thirty-nine of these strains had been previously characterized as P-fimbriated and the remaining non fimbriated strain was used as a negative control. METHODS: Fimbriation was quantitatively studied by electron microscope observation of the strains before and after treatment. To determine possible qualitative variations in the fimbrial proteins and in the external membrane (OMPs), extraction and electrophoretic separation was performed in polyacrylamide gels. RESULTS: No qualitative differences were observed in the OMPs profile and fimbrial proteins induced by ciprofloxacin in any of the strains studied. However, electron microscopic observation generally showed a decrease in the percentage fimbriated bacterial cells by the antimicrobial effect. CONCLUSIONS: The mechanism of action of ciprofloxacin at subinhibitory doses may correspond to a process of fimbrial protein synthesis inhibition secondary to the initiation of general repair mechanism of the cell exposed to the antimicrobial and not to a process of specific mutations which qualitatively affect fimbrial protein composition.     

Responses of natural killer cell activity to acute laboratory stressors in healthy men at different times of day

BACKGROUND: Five renal recipients with neurovesical dysfunction (NVD) were retrospectively reviewed focusing on anatomical and urodynamic abnormalities of the lower urinary tract and their management prior to kidney transplantation. METHODS: The underlying anomalies in these 5 patients were a posterior urethral valve (1 with an imperforate anus; n = 2), meningomyelocele (n = 2) and a congenital short urethra with an imperforate anus (n = 1). Their urinary tracts were evaluated prior to transplantation with voiding cystourethrography, urethrocystoscopy, cystometrography and electromyography of the external urethral sphincter to identify a possible focus of urinary tract infection, urine storage and voiding function. RESULTS: All 5 patients had NVD proven by urodynamic studies or by documentation of urinary retention in the absence of mechanical outlet obstruction. Bilateral high grade vesicoureteral reflux was noted in all patients, requiring ureteroneocystostomy. Clean intermittent catheterization (CIC) was ultimately employed for bladder emptying in all patients. Two patients with poor bladder compliance underwent augmentation cystoplasty before transplantation. The Mitrofanoff procedure was used in 2 patients with structural urethral abnormalities to access the bladder for catheterization. After eradication of possible sources of infection and establishment of a low-pressure urine storage system with bladder emptying by CIC, kidney transplantation was performed. Following kidney transplantation, all of the recipients were asymptomatic for urinary tract infections using CIC. Although 1 patient lost his graft due to chronic rejection, the other 4 other patients have good renal function. CONCLUSION: Kidney transplantation in patients with NVD can be performed provided that their urinary tract problems are properly resolved.     

Hemagglutination ability and adherence to the Buffalo green monkey kidney cell line of uropathogenic Escherichia coli

The hemagglutination ability and adherence capacity to the Buffalo green monkey (BGM) kidney cell line of 160 wild-type strains of Escherichia coli isolated from bacteriuric patients were investigated. It was found that P-fimbriated E. coli strains adhered significantly better to BGM cells than did strains in which P-fimbriae were not detected, which is in accordance with the capacity of P-fimbriated strains to cause unobstructive pyelonephritis and with receptor distribution for P-fimbriae in the urinary tract. The strains which exhibited other adhesions, alone or simultaneously, showed reduced adherence to BGM cells, while non-agglutinating strains, mostly isolated from urine of patients with asymptomatic bacteriuria, did not adhere at all or adhered poorly to the utilized cell line. The BGM cells served as a good experimental model for investigation of uropathogenic E. coli adherence; because these cells originate from the upper urinary tract, they are viable and not coated with Tamm-Horsfall protein.     

Urinary tract infections in infants, an insidious clinical picture

Three boys aged 4, 5 and 7 weeks drank poorly, vomited and were lethargic. There were metabolic disorders attributable to a urinary tract infection. Ultrasonography revealed anatomical anomalies. After antibiotic treatment and, if necessary, surgical correction, the patients recovered. Follow-up was uncomplicated except persisting polyuria in one of the patients. A urinary tract infection in young children is difficult to recognise because of the aspecific presenting symptoms. It can cause a severe metabolic disturbance in which hyponatraemia and hyperkalaemia develop (pseudohypoaldosteronism), combined with metabolic acidosis and polyuria. A high alertness for urinary tract infections in young children with these aspecific symptoms is needed as well as metabolic and urologic evaluation.     

Characteristics of the interaction between thrombin exosite 1 and the sequence 269-287 [correction of 269-297] of platelet glycoprotein Ibalpha

A 6-week-old child with acute urinary tract infection caused by Shiga toxin-producing Escherichia coli (STEC) O5:H-developed hemolytic-uremic syndrome (HUS). Molecular and phenotypic analysis of the urinary isolate indicated that it lacked uropathic properties and that it was probably of intestinal origin. Nevertheless, the patient did not experience a diarrheal prodrome, nor was STEC or Shiga toxin detected in his feces at any time. Examination of the patient's serum pointed to recent infection with E. coli O5, with no evidence of exposure to E. coli O157, O111, or O26. A review of 13 previously reported cases of HUS associated with acute urinary tract infection indicated that this was the first case of nondiarrheal HUS in which infection with the most common STEC serogroups was specifically excluded. This case illustrates the need to investigate patients with nondiarrheal HUS for infection with STEC.     

Development of a rapid assay for detecting gyrA mutations in Escherichia coli and determination of incidence of gyrA mutations in clinical strains isolated from patients with complicated urinary tract infections

The MICs of ofloxacin for 743 strains of Escherichia coli isolated from 1988 to 1994 were determined by testing. The strains were from patients with urinary tract infections complicated by functional or anatomical disorders of the urinary tract. Those determined to be ofloxacin resistant (MIC, > or =12.5 microg/ml) comprised 3 of 395 strains (1.3%) from the 1988 to 1990 group, 2 of 166 strains (1.2%) from the 1991 to 1992 group, and 7 of 182 strains (3.8%) from the 1993 to 1994 group. The incidence of resistant strains increased significantly during this period. The percentage of isolates with moderately decreased susceptibilities to ofloxacin (MIC, 0.39 to 3.13 microg/ml) also rose during the same period. To determine the incidence of gyrA mutations in urinary-tract-derived strains of E. coli, we developed a simple and rapid assay based on PCR amplification of the region of the gyrA gene containing the mutation sites followed by digestion of the PCR product with a restriction enzyme. Using this assay, we examined all 182 strains isolated in 1993 and 1994 for the presence of mutations at Ser-83 and Asp-87 in the gyrA gene. Of these strains, 33 (18.1%) had mutations in the gyrA gene. The incidences of mutations at Ser-83, at Asp-87, and at both codons were 10.4 (19 strains), 4.4 (8 strains), and 3.3% (6 strains), respectively. To determine the correlation of the mutations in the gyrA gene with susceptibilities to quinolones (nalidixic acid, ofloxacin, norfloxacin, and ciprofloxacin), we further examined 116 strains for which the MICs of ofloxacin were > or =0.2 microg/ml that were chosen from the isolates in the 1988 to 1992 group. The MICs of nalidixic acid for the strains without mutations at either Ser-83 or Asp-87 were < or =25 microg/ml, whereas those for the strains with single mutations or double mutations were from 50 to >800 microg/ml. For the fluoroquinolones, significant differences in the distributions of the MICs were observed among the strains without mutations, with single mutations, and with double mutations. The accumulation of mutations in the gyrA gene was associated with an increase in fluoroquinolone resistance. Ofloxacin MICs for the majority of the strains with single and double mutations were 0.39 to 3.13 and 6.25 to 100 microg/ml, respectively. This study demonstrates a chronological increase in the percentage of not only highly fluoroquinolone-resistant strains, corresponding to those with double mutations in the gyrA gene, but also strains with moderately decreased susceptibilities to fluoroquinolones, corresponding to those with single mutations. This increase in the incidence of strains with a single mutation in the gyrA gene portends a further increase in the incidence of strains with clinically significant resistance to fluoroquinolones.     

Increased urinary adrenomedullin excretion in children with urinary-tract infection

BACKGROUND: Adrenomedullin (AM), a smooth-muscle relaxant peptide, is stimulated by cytokines and bacterial endotoxins. We hypothesized that urinary-tract infections may be associated with elevated urinary AM excretion. METHODS: AM in urine was quantified in eleven children with urinary-tract infection and 11 age- and sex-matched controls by radioimmunoassay. RT-PCR was used to demonstrate local AM mRNA expression in the urinary tract. RESULTS: In healthy controls but not in diseased children there was a significant correlation between AM and creatinine in urine (r = 0.91, P < 0.001). AM levels in children with urinary-tract infection were significantly higher than in controls (0.6 +/- 0.41 vs 0.15 +/- 0.14 ng/micromol creatinine; P < 0.001; (means +/- SD)). There was a significant correlation between white cell count and AM in urine (r = 0.78, P < 0.001). AM mRNA was expressed in renal tissue, renal pelvis, ureter, bladder, and urethra. CONCLUSION: The smooth-muscle relaxant peptide adrenomedullin that is synthesized in tissue of the human urinary tract is elevated in urine of patients with urinary-tract infections. A possible consequence might be the interference with the ureteral anti-reflux mechanisms.     

Antibiotic resistance in bacterial urinary tract infections, 1991 to 1997

This study assessed changing patterns of antibiotic resistance in Escherichia coli urinary tract infections at a university student health center during three periods: the first 6 months each of 1991, 1994, and 1997. Urine culture and sensitivity results were taken from available medical records of female patients having urine cultures during the three periods (1991, n = 739; 1994, n = 938; 1997, n = 863); age and ethnicity were also noted. In E. coli isolates (the majority of positive cultures), resistance to four antibiotics changed significantly: ampicillin (30% to 45% to 39%), carbenicillin (29% to 42% to 39%), tetracycline (29% to 40% to 23%), and trimethoprim/sulfamethoxazole (15% to 32% to 15%). The results raise questions regarding the future clinical reliability of several commonly used antibiotics in the treatment of urinary tract infection.     

Non-specific seminal tract infection and male infertility: a bacteriological study

70 infertile males with epididymal tenderness, pus cells in the semen, and/or history of urinary tract infection were studied by semen culture examination. Significant growth of Streptococcus fecalis, Escherichia coli, coagulase positive Staphylococci, Proteus valgaris, Pseudomonas pyocyanea, and beta hemolytic Strepticocci was found in 42.9% of the cases. Most of the tested strains were sensitive to ampicillin, cotrimoxazole, nitrofurantoin, erythromycin, and chloramphenicol. In a control group of 20 healthy fertile males, only an insignificnat growth of Staphylococcus albus and Streptococcus facalis was found in 65% of the samples. Nonspecific seminal tract infection can be an important cause of male infertility. These infections may affect fertility in several ways: by damaging sperm, hampering their motility, altering the chemical composition of the seminal fluid, or by producing an inflammatory structure in the tract. Seminal infection could also be the cause of the chronicity of urinary tract infection by acting as the reservoir of infection.     

Serum response of Escherichia coli strains causing dyspepsia and urinary tract infection: relation to alpha-hemolysin production and O type

A total of 109 alpha-hemolytic and 104 nonhemolytic Escherichia coli isolates from children with dyspepsia and urinary tract infections were investigated for resistance to the bactericidal activity of human serum. A significantly higher proportion of serum resistance was found in alpha-hemolytic E. coli isolates than in nonhemolytic isolates (P < 0.01). An association between the titer of alpha-hemolysin produced and serum resistance was found.     

Binding characteristics of S fimbriated Escherichia coli to isolated brain microvascular endothelial cells

To assess the role of S fimbriae in the pathogenesis of Escherichia coli meningitis, transformants of E. coli strains with or without S fimbriae plasmid were compared for their binding to microvessel endothelial cells isolated from bovine brain cortices (BMEC). The BMEC's displayed a cobblestone appearance, were positive for factor VIII, carbonic anhydrase IV, took up fluorescent-labeled acetylated low density lipoprotein, and exhibited gamma glutamyl transpeptidase activity. Binding of S fimbriated E. coli to BMEC was approximately threefold greater than nonfimbriated E. coli Similarly S fimbriated E. coli bound to human brain endothelial cells approximately threefold greater than nonfimbriated E. coli. Binding was reduced approximately 60% by isolated S fimbriae and about 80% by anti-S adhesin antibody. Mutating the S adhesin gene resulted in a complete loss of the binding, whereas mutagenesis of the major S fimbriae subunit gene sfaA did not significantly affect binding. Pretreatment of BMEC with neuraminidase or prior incubation of S fimbriated E. coli with NeuAc alpha 2,3-sialyl lactose completely abolished binding. These findings indicate that S fimbriated E. coli bind to NeuAc alpha 2,3-galactose containing glycoproteins on brain endothelial cells via a lectin-like activity of SfaS adhesin. This might be an important early step in the penetration of bacteria across the blood-brain barrier in the development of E. coli meningitis.     

Localization of a domain in the FimH adhesin of Escherichia coli type 1 fimbriae capable of receptor recognition and use of a domain-specific antibody to confer protection against experimental urinary tract infection

The FimH subunit of type 1-fimbriated Escherichia coli has been implicated as an important determinant of bacterial adherence and colonization of the urinary tract. Here, we sought to localize the functionally important domain(s) within the FimH molecule and to determine if antibodies against this domain would block adherence of type 1-fimbriated E. coli to the bladder mucosa in situ and in vivo in an established mouse model of cystitis. We generated translational fusion proteins of disparate regions of the FimH molecule with an affinity tag MalE, and tested each of the fusion products in vitro for functional activity. The minimum region responsible for binding mouse bladder epithelial cells and a soluble mannoprotein, horseradish peroxidase, was contained within residues 1-100 of the FimH molecule. We validated and extended these findings by demonstrating that antibodies directed at the putative binding region of FimH or at synthetic peptides corresponding to epitopes within the binding domain could specifically block type 1 fimbriae-mediated bacterial adherence to bladder epithelial cells in situ and yeast cells in vitro. Next, we compared the ability of mice passively immunized intraperitoneally with antisera raised against residues 1-25 and 253-264 of FimH or 1-13 of FimA to resist bladder colonization in vivo after intravesicular challenge with type 1-fimbriated E. coli. Only the antibody directed at the putative binding region of FimH (anti- s-FimH1-25) significantly reduced E. coli bladder infections in the experimental mouse model of urinary tract infections. Similar results were obtained when the mice were actively immunized with synthetic peptides corresponding to residues 1-25 and 253-264 of FimH or 1-13 of FimA. The mechanism of protection was attributed, at least in part, to inhibition of bacterial adherence to the bladder surface by s-FimH1-25-specific antibody molecules that had filtered through the kidneys into the urine. The level of FimH antibodies entering the bladder from the circulatory system of the immunized mice was found to be markedly enhanced upon bacterial challenge. The potential broad spectrum activity of the protective FimH antibody was indicated from its serologic cross-reactivity with various urinary tract bacterial isolates bearing type 1 fimbriae. These findings could be relevant in the design of an efficacious and broadly reactive FimH vaccine against urinary tract infections.     

Legal rights of veterinarians under veterinary Good Samaritan statutes and equine liability statutes

OBJECTIVE: To determine the prevalence and clinical features of Candida species in hospital-acquired urinary tract infections (UTI) in a neonatal intensive care unit. DESIGN: A retrospective study was conducted of hospital-acquired UTI occurring in infants admitted to a neonatal intensive care unit between January 1, 1989, and June 30, 1995. Hospital-acquired infection was defined as one occurring in an infant who was at least 7 days of age and hospitalized since birth. Urinary tract infection was defined by a urine culture yielding a single organism with > 1000 colony-forming units/ml from a suprapubic aspiration or > 10,000 colony-forming units/ml via urethral catheterization. RESULTS: Fifty-seven infants had 60 UTI during the study period. Candida spp. were responsible for 25 of 60 (42%) UTI. The median gestational age of infants with candidal UTI was 26 weeks (range, 23 to 37) which was significantly less than that for infants with bacterial UTI, 28 weeks (range, 23 to 40) (P = 0.04). Candidemia was present in 13 of 25 (52%) candidal UTI which was significantly more often than bacteremia with bacterial UTI, 3 of 35 (8%) (odds ratio, 11.6; 95% confidence interval, 2.8 to 47.8). The median age of infection for candidal UTI was 34 days (range, 9 to 228), which was significantly earlier than for bacterial UTI, 79 days (range, 7 to 247) (P = 0.003). Renal pelvis fungus balls were present in 7 of 20 (35%) infants with candidal UTI who had renal ultrasound studies. CONCLUSIONS: Candida spp. were the pathogens identified in 42% of hospital-acquired urinary tract infections in a neonatal intensive care unit. Candidemia was associated with 52% of candidal UTI and bacteremia with 8% of bacterial UTI. Candidal UTI occurred significantly earlier than bacterial UTI. Renal fungus balls were present in 35% of infants with candidal UTI.     

Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1995). II. Background of patients

Clinical background was investigated on patients with urinary tract infections (UTIs) from whom 785 bacterial strains were isolated in 11 hospitals during the period from June, 1995 through May, 1996. 1. Distributions of age and sex of patients and type of infections. Among the patients examined, those with ages 50 years or older were the most frequent (males: 80.5%, females: 69.7%), and, among females, those with ages in the 20's were 12.6%. With regard to types of infections, more than a half of infections among males were of complicated types, but most of infections among females were of uncomplicated types, especially among females of ages less than 60 years. 2. Ages of patients and types of pathogens. The higher the ages of patients, the lesser became the isolation frequencies of Proteus spp. and Serratia spp., but the higher were those of Klebsiella spp. and Pseudomonas spp. 3. Effect of antibiotic use on isolation frequencies of pathogens. Use of antibiotics decreased pathogens isolated from patients with uncomplicated UTIs drastically (237 isolates before antibiotics compared to 33 after). Even isolated pathogens from patients with complicated UTIs decreased drastically with the use of antibiotics when indwelling catheters were not in use (200 isolates before antibiotics compared to 83 after), but when indwelling catheters were in use, antibiotics apparently failed to decrease the isolation frequency. 4. Surgical procedures and types of causative organisms for UTIs. Escherichia coli was the most frequently isolated organism from uncomplicated cases of UTIs. From cases of complicated UTIs without indwelling catheters, Enterococcus faecalis was the most frequently isolated, followed by E. coli, P. aeruginosa and Klebsiella spp. When a surgical procedures were not done, E. coli was isolated most frequently. From cases of complicated UTIs with indwelling catheters, P. aeruginosa, E. faecalis and S. aureus were the organisms that were mainly isolated, with isolation frequencies of 23.9%, 17.3% and 12.7%, respectively. When no surgical procedures were used, isolation frequencies of P. aeruginosa, Klebsiella spp. and E. faecalis were 25.7%, 14.3% and 14.3%, respectively.