VIRULENCE CHARACTERISTICS AND DNA FINGERPRINTS OF ESCHERICHIA COLI ISOLATED FROM WOMEN WITH ACUTE UNCOMPLICATED PYELONEPHRITIS

Purpose

Previous studies indicated that acute pyelonephritis in infants is initiated by the dominance of uropathogenic strains in fecal flora. Such pathogenic evidence, however, is still lacking for adult women. In this study, the validity of a fecal-perineal-urethral hypothesis in acute uncomplicated pyelonephritis of adult women was assessed at a genetic level.

Materials and Methods

A total of 1,200 Escherichia coli isolates from the urine and rectal swab of 12 adult women with acute uncomplicated pyelonephritis were examined. The clonality of the urinary and fecal isolates was evaluated by genotyping of 6 urovirulence determinants and pulsed-field gel electrophoresis. Furthermore, urovirulence genotypes were examined in E. coli isolates from the rectal swab of 30 normal healthy women (mean 26.7 isolates per person).

Results

The E. coli strains causing pyelonephritis were present in the rectal swab in 10 of 12 patients and were a predominant fecal clone in 9 cases. Also, P-fimbriated strains dominated in the fecal flora in 10 of 30 normal healthy women.

Conclusions

The clonal identity of the urinary and fecal strains in acute pyelonephritis clearly supports the fecal-perineal-urethral hypothesis.     

Biofilm formation in uropathogenic Escherichia coli strains: relationship with prostatitis, urovirulence factors and antimicrobial resistance

PURPOSE: Escherichia coli strains are the most frequent cause of urinary tract infections. Biofilm formation allows the strains to persist a long time in the genitourinary tract and interfere with bacterial eradication. We determined the possible relationships between the different urinary tract infections, and in vitro biofilm formation, the presence of urovirulence factors and nalidixic acid resistance. MATERIALS AND METHODS: A total of 151 E. coli strains collected from patients with cystitis (44 strains), pyelonephritis (75) and prostatitis (32) were analyzed for in vitro biofilm formation, the phylogenetic group, the presence of several urovirulence factors and resistance to nalidixic acid. RESULTS: E. coli strains causing prostatitis produced biofilm in vitro more frequently than those causing other urinary tract infections and had a higher frequency of hemolysin (p = 0.03 and 0.0002, respectively). However, only hemolysin was independently associated with prostatitis. On the other hand, strains forming biofilm presented a significantly higher frequency of hemolysin and type 1 fimbriae expression. CONCLUSIONS: Although hemolysin is the main virulence factor by which E. coli causes acute prostatitis, the association between hemolysin and biofilm formation may result in increased ability of E. coli strains to persist in the prostate.     

Escherichia coli Virulence Factors and Serotypes in Acute Bacterial Prostatitis

Background Escherichia coli is the most frequent pathogen in both acute bacterial prostatitis and acute uncomplicated urinary infections. To assess the virulence profiles of E. coli in acute prostatitis, the serotypes and virulence factor (VF) genotypes were determined.
Methods We studied 107 E. coli isolates from cases of acute bacterial prostatitis, 76 isolates from acute pyelonephritis, 194 isolates from acute cystitis and 80 fecal isolates from healthy people. All pyelonephritis and cystitis isolates were from women. Seven urovirulence determinants were analyzed by DNA colony hybridization, including the genes for type 1 fimbria (pil) , P fimbria (pap) , S fimbria (sfa) , afimbrial adhesin AFA-I (afal), α -hemolysin (hly) , cytotoxic necrotizing factor 1 (cnfl) and aerobactin (aer). 0:H:K serotypes were also determined.
Results With the exception of pil and afal , all VFs were significantly more often associated with prostatitis, pyelonephritis and cystitis isolates than with the fecal isolates. The prevalence of sfa, hly and cnfl was higher in prostatitis isolates than in pyelonephritis and cystitis isolates, and the pap⁺sfa⁺hly⁺cnf⁺ genotype was dominant among prostatitis isolates (48.8%). Nine O serotypes(01, 02, 04, 06, 01 6, Ol 8, 022, 025 and 075) accounted for 79.4%, 73.7% and 78.4% of the prostatitis, pyelonephritis and cystitis strains, respectively. There was an apparent correlation between serotype and genotype in uropathogenic E. coli.
Conclusion The predominance of O serotypes in female urinary tract infections and a high percentage of multiple VFs among the prostatitis isolates suggested that VFs play important roles in the pathogenesis of acute bacterial prostatitis.     

Pharmacological principles in the treatment of urinary tract infections

The ideal antibacterial drug for urinary tract infections should eliminate most urinary pathogens but not alter the colonic flora. Levels in the urine can be attained with the beta-lactam and aminoglycoside antibiotics which are up to several powers of 10 higher than the minimal inhibitory concentration values of the causative organisms. At these levels even penicillin G eliminates many Gram-negative urinary pathogens. Trimethoprim has a lesser propensity to select resistant organisms than most other antimicrobials. It occurs in vaginal secretions and reduces the number of Enterobacteriaceae surrounding the urethral orifice, thereby diminishing the chance of an ascending reinfection, and it is often effective in the treatment of bacterial prostatitis as it reaches therapeutic concentrations in prostatic secretions. Tetracycline therapy, however, carries a substantial chance of bacterial resistance at the next reinfection of the urinary tract, as these antibiotics produce almost uniform resistance in Escherichia coli in the faecal flora. Failure to respond to single-dose therapy actually implies the presence of antibody-coated bacteria in the urine, which in turn implies an upper tract or prostatic infection. This is an easy means of indicating which patients require further evaluation by intravenous pyelography or cystoscopy.     

Classification and diagnosis of prostatitis: a gold standard?

The National Institutes of Health Classification System for prostatitis has now been accepted by the North American and International urology community. This categorization system consists of category I (acute bacterial prostatitis), category II (chronic bacterial prostatitis), category III (chronic prostatitis/chronic pelvic pain syndrome - CP/CPPS) and category IV asymptomatic inflammatory prostatitis. The evaluation of a patient with category I and category II bacterial prostatitis consists of history and physical examination and urine culture for lower urinary tract localization cultures, respectively. The clinical tests for the evaluation of CP/CPPS can be classified as mandatory, recommended and optional. Mandatory evaluations include history and physical examination, urinalysis and urine culture. Recommended evaluations include lower urinary tract localization tests, symptom index, flow rate, residual urine determination and urine cytology. Optional evaluations include semen analysis and culture, urethral swab, urodynamics, cystoscopy, imaging, and prostate specific antigen determination. The physician must individualize a rational diagnostic strategy for each patient. There is no 'gold standard' for the diagnosis and evaluation of patients presenting with prostatitis.     

Detailed histopathological examination contributes to the assessment of Escherichia coli urovirulence.

To determine the usefulness of detailed histopathological evaluation in the assessment of urovirulence of different Escherichia coli strains in a mouse model of ascending, unobstructed urinary tract infection, and to evaluate the relationship between susceptibility to urinary tract infection and renal levels of P fimbrial receptor glycolipids in different mouse strains, female Swiss Webster and Balb/c mice were inoculated transurethrally with one of four different well-characterized wild type E. coli strains or with an E. coli K-12 laboratory strain, and renal glycolipid levels were determined for both mouse strains. In Swiss Webster mice, each of the wild type E. coli strains was more virulent than the laboratory strain by both microbiological and histopathological criteria. Despite the common origin and identical virulence factor profiles of the three urosepsis isolates studied, one was significantly less urovirulent than the other two. Paradoxically, this strain stimulated a greater degree of leukocytosis than did the more urovirulent strains. Balb/c mice were significantly more susceptible to infection with this strain than were Swiss Webster mice, a difference possibly contributed to by the significantly higher renal levels of P fimbrial receptor glycolipids in Balb/c mice. Detailed histopathological analysis revealed significant differences in virulence between bacterial strains, and in susceptibility to infection between different mouse strains, that were inapparent from culture results alone.     

Distribution of afaE adhesins in Escherichia coli isolated from Japanese patients with urinary tract infection

PURPOSE: Afimbrial adhesin is known to be one of the most prevalent virulence factors in uropathogenic Escherichia coli. A recent report showed that the new subtype afaE8 predominated in afa positive isolates from patients with pyelonephritis (55.6%), suggesting that this subtype may be an important factor in ascending urinary tract infections. MATERIALS AND METHODS: A total of 457 E. coli strains consisting, of 194, 76 and 107 isolates from patients with cystitis, pyelonephritis and prostatitis, respectively, and 80 isolates from the rectal flora of healthy individuals were subjected to polymerase chain reaction to determine the afa operon as well as afaE subtypes.RESULTS: We identified 32 afa positive isolates of 377 strains (8.5%) and 2 of 80 strains (2.5%) from urinary tract infection isolates and normal flora, respectively. When afaE subtypes were determined, the afaE3 subtype predominated in afa positive isolates from cystitis (64.7%), pyelonephritis (66.7%) and prostatitis (50%). However, the afaE8 subtype was absent from urinary tract infection isolates, while only 1 isolate from the stool of a healthy adult harbored this subtype. CONCLUSIONS: Our data show that the afaE3 subtype predominated in pyelonephritis as well as in other urinary tract infections, indicating that the afa gene may be important in urinary tract infection. However, the distribution of afaE subtypes may be diverse in different areas of the world.     

Serum antibody titers in urethritis and chronic bacterial prostatitis.

Serum antibody titers were measured by direct bacterial agglutination technique against various strains of Escherichia coli found in the fecal flora of a control group of men who had no history of genitourinary tract infection, against the strains of E. coli responsible for urethral infection in 7 men with urethritis, and against the strains of E. coli responsible for prostatic infection in 25 men with chronic prostatitis. Low serum titers were found in both the control group (median titer of 1:20) and in the urethritis group (median titer of 1:10). Excluding 3 men who had self-agglutinating strains, 18 of 22 (82 per cent) in the prostatitis group had serum titers of 1:320 or greater (median titer of 1:640). Measurement of serum antibody titers by this technique can be a valuable adjunct to diagnosis in cases of chronic prostatitis due to strains of E. coli.     

青少年尿路感染细菌分布以及耐药性分析

【摘要】 目的 探究近一年来深圳光明新区尿路感染青少年患者细菌分布情况和耐药情况。方法将2014年7月到2015年7月就诊光明新区医院的18~20岁尿路感染患者44例作为研究对象,收集中段尿分离培养细菌共得1382株菌落,分析尿路感染细菌的种类、分布和通过药敏试验分析耐药性。结果〓革兰氏阳性菌20.12%,真菌3.04%,革兰氏阴性菌76.85%;屎肠球菌37.41%,近平滑假丝酵母菌38.10%,大肠埃希菌50.47%。金黄色葡萄球菌对环丙沙星耐药性最强,屎肠球菌耐药性最强的为左氧氟沙星,粪肠球菌耐药性最强的为克林霉素,大肠埃希菌耐药性最强的为头孢曲松,铜绿假单胞菌耐药性最强的为氨曲南,肺炎克雷伯菌耐药性最强的为头孢曲松,柠檬酸杆菌耐药性最强的为环丙沙星。结论〓对于18~20的青少年岁的尿路感染患者,革兰氏阴性菌尤其是大肠埃希菌为主产生耐药性较为广泛。     

The presence of the virulence island containing the usp gene in uropathogenic Escherichia coli is associated with urinary tract infection in an experimental mouse model

PURPOSE: A putative virulence island commonly noted in the genome of uropathogenic Escherichia coli strains has recently been reported. We have observed that the island includes a gene consisting of a protein designated uropathogenic specific protein (usp) and 3 small open reading frames (orfU1-3). In our current study we assessed the importance of the genes located in the putative virulence island in the pathogenesis of urinary tract infection using a mouse pyelonephritis model. MATERIALS AND METHODS: A total of 427 E. coli strains isolated from the urine of 194, 76 and 107 subjects suffering from cystitis, pyelonephritis and prostatitis, respectively, and 50 isolates from the feces of healthy individuals were examined for genotypes and serotypes. In addition, several recombinant E. coli strains possessing usp and/or orfU1 to 3 were constructed for evaluating the significance of these genes using an experimental pyelonephritis mouse model. RESULTS: The usp was significantly more often associated with uropathogenic E. coli strains (79.4% from cystitis, 93.4% from pyelonephritis and 88.8% from prostatitis) than with fecal E. coli strains from healthy individuals (24%). Furthermore, usp was frequently associated with all common serotypes of uropathogenic E. coli (71.7% to 100%). In challenge experiments using the mouse urinary tract infection model the vector possessing usp significantly enhanced the infectibility of the E. coli host cell, whereas the 3 small proteins at the downstream of usp failed to show the effect. CONCLUSION: Our results indicate that usp may contribute to the causation of urinary tract infection and may be considered a major virulence determinant of uropathogenic E. coli.     

Experimental prostatitis in nonhuman primates: II. Ascending acute prostatitis

Bacterial prostatitis is a common cause of urinary tract infection in males, but little is known of its pathophysiology. To study this, we developed a nonhuman primate model using a wild-type clinical isolate of Escherichia coli. Primates have a prostatic anatomy that is similar to humans, which makes them ideal as an animal model of this disease. The monkeys had a urethral inoculation of this organism and were then followed with urine, blood, and semen cultures, white blood counts, and renal scans. They were sacrificed at from 10 days to 4 weeks, and their genitourinary tracts histologically examined. The prostatitis paralleled that reported in humans, and we conclude that the infection occurs by the ascending route. The organisms causing the infection in man do so in our primate model, and the histologic change is also the same. Thus, the primate model holds promise for studies to help us understand this disease.     

慢性非细菌性前列腺炎患者的前列腺液和前列腺组织中的细菌16SrRNA基因检测

目的:探讨细菌在慢性非细菌性前列腺炎病因中的作用,评估细菌16S核糖体核糖核酸(16SrRNA)基因在前列腺液标本和前列腺组织标本中检出的差异.方法:应用PCR方法检测38例慢性非细菌性前列腺炎患者的前列腺液和前列腺组织中细菌16SrRNA基因,同时对照检测尿道拭子和直肠拭子以及穿刺枪头拭子的细菌16SrRNA基因.结果:细菌16SrRNA基因的检出率在前列腺液中和前列腺组织中分别为 78.9%和81.5%(P＞ 0.05).细菌基因信号在前列腺液标本中和尿道拭子中各有30例( 78.9%)和4例( 10.5%)呈阳性(P＜ 0.01);在前列腺组织中和直肠拭子中各有31例( 81.5%)和6例( 15.8%)呈阳性(P＜ 0.01),无一例穿刺枪头拭子阳性.结论:慢性非细菌性前列腺炎患者的前列腺液和前列腺组织中均有细菌16SrRNA基因的检出,其病因可能与细菌感染有关. 细菌16SrRNA基因的检出在前列腺液标本和前列腺组织标本中差异无统计学意义.     

Experimental prostatitis in nonhuman primates: I. Bacterial adherence in the urethra

Both man and monkey possess urothelial (transitional cell) receptors for P-fimbriae of Escherichia coli; however, the male urethra has pseudostratified columnar cells. We studied adherence using scanning electron microscopy and found that P-fimbriae were the principal mediators of adherence to these cells as well. The monkey, therefore, should be a good model for the study of the ascending route of infection in prostatitis, the route thought to occur in man.     

A case of acute bacterial prostatitis caused by gram positive cocci]

This report describes our experience with sulbactam/cefoperazone in the treatment of a 36-year-old man with acute prostatitis (complicated with bilateral epididymitis) caused by S. salivarius. The patient had no past history suggesting the relationship between this organism and the route of infection. The isolated strain exhibited a high susceptibility to the drug and symptoms subsided after treatment with a daily dose of 4 g sulbactam/cefoperazone for 7 days. Usually, the most causative bacteria of acute prostatitis are either GNR or E. faecalis. However, as in the present case, there may be very few cases in which the infection has been caused by a strain of Streptococcus species.     

Laboratory and clinical study of sulbactam/cefoperazone (SBT/CPZ) on bacterial prostatitis]

The cefoperazone and sulbactam concentrations in human prostatic fluid were measured following intravenous administration of sulbactam/cefoperazone (SBT/CPZ) and its clinical efficacy and safety in the treatment of 11 patients with acute or chronic bacterial prostatitis were evaluated. Cefoperazone concentrations in prostatic fluid (PF) one hour after an intravenous infusion of SBT/CPZ at a dose of 1 g and 2 g were 0.57 +/- 0.26 micrograms/ml and 1.37 +/- 0.86 micrograms/ml, respectively, both exceeding the MIC against most of the isolated strains from expressed prostatic secretion (EPS). The sulbactam levels in PF at doses of 1 g and 2 g of SBT/CPZ were 0.30 +/- 0.18 micrograms/ml and 0.38 +/- 0.13 micrograms/ml, respectively, both of which were high enough to potentiate antimicrobial activity of cefoperazone. The peak of MIC distribution of sulbactam/cefoperazone against E. coli (14 strains) and S. epidermidis (21 strains) isolated from EPS of patients with bacterial prostatitis was in a range of 0.1-0.2 micrograms/ml and 0.2-0.78 micrograms/ml as described for the cefoperazone concentration, respectively, which were superior to those of cefoperazone, ceftazidime and piperacillin, all compared as control, SBT/CPZ exhibited 8 fold or more potent antimicrobial activity than cefoperazone against beta-lactamase producing E. coli and CNS. Clinically, SBT/CPZ was given to 11 patients diagnosed as having bacterial prostatitis in a daily dose of 2-4 g for 5 to 8 days. The drug was found to be effective in all (100%) of 5 patients with acute prostatitis and in 3 (75.0%) of 4 patients who were judged to be assessable among 6 chronic patients. No side effects of any kind were observed in any of the patients treated. In laboratory tests, a transient thrombocytopenia was reported for one patient. SBT/CPZ is particularly useful in the treatment of acute bacterial prostatitis caused by GNR. This drug is useful for chronic prostatitis those, caused primarily by CNS which is susceptible to this agent. This drug is available as an injectable form, subjects for its appropriate usage will be those who show acute exacerbation of infection or who do not respond to oral therapy.     

Bacterial prostatitis

Objectives

The prostatitis syndrome is classified into bacterial prostatitis (acute and chronic), chronic pelvic pain syndrome and asymptomatic prostatitis. The aim of this report is to review current management standards for bacterial prostatitis.

Methods

A research was performed on literature dealing with acute and chronic bacterial prostatitis.

Results

There is a consensus on diagnostic management of bacterial prostatitis comprising microbiological sampling of midstream urine in acute bacterial prostatitis and performance of a bacterial localisation test in chronic bacterial prostatitis. Approximately 10 % of acute bacterial prostatitis cases eventually develop into chronic bacterial prostatitis and further 10 % into chronic pelvic pain syndrome. Bacterial isolates causing acute bacterial prostatitis are highly virulent strains comprising an array of different virulence factors. Presumably, the additional ability of isolates to form biofilms might be one factor amongst others to facilitate development of chronic bacterial prostatitis. Therapy for infectious prostatitis is standardised with antibiotics as the primary agents, empirically administered in acute prostatitis and after susceptibility testing in chronic bacterial prostatitis. Fluoroquinolones exhibit more favourable pharmacological properties; therefore, fluoroquinolones have been recommended as first-line agents in the treatment for chronic bacterial prostatitis. Antibiotic resistance to fluoroquinolones, however, is increasing and is posing significant clinical problems. Further studies on alternative antibiotics active within the prostate are therefore needed both for prophylaxis in transrectal prostate biopsy, for example, and for therapy of chronic bacterial prostatitis.

Conclusions

Bacterial prostatitis has developed into well-managed entities with increasing antimicrobial resistance being the most severe drawback of yielding therapeutic success.     

Characterization of Escherichia coli strains causing urinary tract infections in patients with transposed intestinal segments

PURPOSE: Transposition of intestinal segments into the urinary tract predisposes to urinary tract infections. We characterized bacterial infections in these patients and examined the virulence genotype and persistence of Escherichia coli isolates. MATERIALS AND METHODS: We followed 26 patients who underwent bladder reconstructive surgery using transposed intestinal segments. E. coli strains isolated from the urine of these patients were genotyped for established virulence determinants and the frequency of carriage was compared with E. coli strains isolated from community acquired urinary infections and the fecal flora of anonymous volunteers. A longitudinal study of E. coli strains in 9 patients was also done using pulsed field gel electrophoresis. RESULTS: E. coli was the most frequently isolated organism, responsible for 59% (62 of 105) of monobacterial infections. Other bacteria isolated included Klebsiella species, Proteus species and Enterococcus faecalis. Community acquired E. coli strains were more likely to carry multiple determinants for particular adhesins (P and S fimbriae) and toxins (alpha-hemolysin and cytotoxic necrotizing factor) than fecal strains. Carriage frequency for bladder reconstruction strains was intermediary and not significantly different. The key finding was that E. coli strains persisted for prolonged periods, including 2 years in certain patients, often despite various antimicrobial treatments. CONCLUSIONS: This study highlights that further steps must be taken to prevent and treat urinary tract infections in this susceptible group. Particular attention should be given to the treatment of persistent infections.     

Does the chronic prostatitis/pelvic pain syndrome differ from nonbacterial prostatitis and prostatodynia?

PURPOSE: The new consensus classification considers the chronic prostatitis/pelvic pain syndrome (CPPS) based on presence or absence of leukocytes in the expressed prostatic secretions, post-massage urine or seminal fluid analysis. We compared classification based on evaluation of these 3 specimens to the traditional classification based on expressed prostatic secretion examination alone. MATERIALS AND METHODS: A prospective clinical and laboratory protocol was used to evaluate symptomatic patients who had no evidence of urethritis, acute bacterial prostatitis or chronic bacterial prostatitis. RESULTS: Thorough clinical and microbiological evaluation of 310 patients attending our prostatitis clinic was used to select a population of 140 subjects who provided optimal expressed prostatic secretion, post-massage urine and semen specimens. Inflammation was documented in 111 (26%) of 420 samples, including 39 expressed prostatic secretion samples with 500 or greater leukocytes/mm.3, 32 post-massage urine samples with 1 or greater leukocytes/mm.3 and 40 seminal fluid specimens with 1 or greater million leukocytes/mm.3. Of the 140 subjects 73 (52%) had inflammatory chronic prostatitis/pelvic pain according to the consensus criteria but only 39 (28%) had nonbacterial prostatitis according to traditional expressed prostatic secretion criteria (p <0.001). CONCLUSIONS: The new consensus concept of inflammatory chronic prostatitis/pelvic pain includes almost twice as many patients as the traditional category of nonbacterial prostatitis.     

Clinico-bacteriological studies on the etiology of bacterial prostatitis. II. Virulence factors of E. coli in bacterial prostatitis

The virulence factors of E. coli in bacterial prostatitis were studied using 59 E. coli isolated from uncomplicated prostatitis. O-antigens of prostatitis-derived E. coli belonged to some specific serotypes such as 0-4, 6, 18, 22 and the haemolysin production was positive in 64.4%. With regard to the fimbriae, the majority of the strains had type 1 fimbriae (81.4%). Mannose resistant (MR) fimbriae were also positive in 59.3% and both type 1 and MR fimbriae were positive in 55.9%. Among MR strains, P-fimbriated and S-fimbriated strains were present in 25.7% and 28.6%, respectively, indicating that these two MR fimbriae were not always specific for the prostatitis-derived E. coli. Although the specific adhesion of E. coli onto the human prostatic epithelium mediated by MR-fimbriae was equivocal, that mediated by type 1 fimbriae was observed clearly. Therefore, type 1 fimbriae was thought to be one of the most significant virulence factors in the pathogenesis of prostatitis caused by E. coli.     

Clinico-bacteriological studies on the etiology of bacterial prostatitis. I. The distribution of clinical isolates and bacteria-specific immunoglobulin in EPS

The distribution of clinical isolates from patients with prostatitis and pathogenicity of the isolates were studied. A new method for measuring the bacteria-specific immunoglobulins in expressed prostatic secretion (EPS) was developed and used for the detection of local immuno-reaction against pathogenic bacteria in the cases with prostatitis. There were no cases with increased antibodies specific for gram-positive cocci (GPC), indicating that the pathogenecity of GPC in bacterial prostatitis was doubtful. On the other hand, specific antibodies against gram negative rods (GNR) were elevated in all cases with acute prostatitis and changes of the antibody titers were correlated well to clinical courses. The present clinico-statistic and immuno-biological studies re-confirmed that E. coli was the main organism in uncomplicated bacterial prostatitis.