Escherichia coli virulence factors and serotypes in acute bacterial prostatitis

The role of red ginseng in men's reproductive health: a literature review

BACKGROUND

Red ginseng (RG) is a traditional herb commonly used in China, Korea, and other East Asian countries. Recently, it has demonstrated a better clinical value in men's reproductive health (MRH). The present review aimed to examine the effects of RG treatment on MRH.

RESULTS

Overall, 42 articles related to RG application in MRH were reviewed, of which 31 were animal experiments and 11 were clinical studies. Furthermore, this review analyzed the use of RG in some male reproductive diseases in clinical trials and determined the associated mechanisms of action. The mechanism of action of RG in MRH may be related to oxidative stress, regulation of sex hormones and spermatogenesis-related proteins, and anti-inflammation.

CONCLUSIONS

The application of RG for the treatment of male infertility, erectile dysfunction, and prostate diseases has the potential to contribute to MRH.

A comparison of different O-antigen serogroups of Escherichia coli in semen samples of fertile and infertile men

Objective

Male genital tract infections have been associated with infertility, and Escherichia coli has drawn increasing attention as an important bacterium in this context. This investigation aimed to characterize and compare the distributions of O-antigen serogroups of E. coli in the semen samples of fertile and infertile men.

Methods

In this case-control study, semen samples were collected from 618 fertile and 1,535 infertile men. The E. coli-positive samples were evaluated in terms of concentration, morphology, viability, and motility parameters according to the World Health Organization 2010 guidelines. Finally, different serogroups of E. coli were identified by multiplex polymerase chain reaction targeting the O-antigen variations of the bacterium.

Results

The prevalence of E. coli among fertile men was significantly higher than among infertile men (p<0.001). The sperm morphology, viability, and motility in the E. coli-positive fertile group were significantly higher than in the E. coli-positive infertile group (p<0.001). E. coli O6 was the most prevalent serogroup found in both groups. However, there was no significant difference in the frequency of different serogroups of E. coil between the two groups (p=0.55).

Conclusion

Despite the higher prevalence of E. coli among fertile men, E. coli had more detrimental effects on semen parameters in infertile men. There was no significant difference in E. coli serogroups between the fertile and infertile groups.

Prospective Study in Children with Complicated Urinary Tract Infection Treated with Autologous Bacterial Lysates

Antimicrobial bacteria resistance is an important problem in children with recurrent urinary tract infections (rUTI), thus it is crucial to search for alternative therapies. Autologous bacterial lysates (ABL) may be a potential treatment for rUTI. Twenty-seven children with rUTI were evaluated for one year, urine and stool cultures were performed, 10 colonies of each culture were selected and those identified as Escherichia coli were characterized by serology. For patients who presented ≥105 UFC/mL, an ABL was manufactured and administered orally (1 mL/day) for a month. Twelve children were monitored for ≥1-year, 218 urine and 11 stool samples were analyzed. E. coli (80.5%) was the main bacteria isolated from urine and feces (72%). E. coli of classical urinary serotypes (UPEC), O25:H4, O75:HNM, and O9:HNM were identified in patients with persistent urinary infection (pUTI). In 54% of patients treated with ABL, the absence of bacteria was observed in urine samples after 3 months of treatment, 42% of these remained without UTI between 10-12 months. It was observed that the use of ABL controlled the infection for almost 1 year in more than 60% of the children. We consider it necessary to develop a polyvalent immunogen for the treatment and control of rUTI.

Santos AC, Cayô R, Gales AC, A. T. Gomes T. Frequency and Diversity of Hybrid Escherichia coli Strains Isolated from Urinary Tract Infections

(1) Background: Hybrid uropathogenic Escherichia coli (UPEC) strains carry virulence markers of the diarrheagenic E. coli (DEC) pathotypes, which may increase their virulence potential. This study analyzed the frequency and virulence potential of hybrid strains among 452 UPEC strains. (2) Methods: Strains were tested for the DEC virulence diagnostic genes’ presence by polymerase chain reaction (PCR). Those carrying at least one gene were classified as hybrid and further tested for 10 UPEC and extraintestinal pathogenic E. coli (ExPEC) virulence genes and phylogenetic classification. Also, their ability to produce hemolysis, adhere to HeLa and renal HEK 293T cells, form a biofilm, and antimicrobial susceptibility were evaluated. (3) Results: Nine (2%) hybrid strains were detected; seven of them carried aggR and two, eae, and were classified as UPEC/EAEC (enteroaggregative E. coli) and UPEC/aEPEC (atypical enteropathogenic E. coli), respectively. They belonged to phylogroups A (five strains), B1 (three), and D (one), and adhered to both cell lineages tested. Only the UPEC/EAEC strains were hemolytic (five strains) and produced biofilm. One UPEC/aEPEC strain was resistant to third-generation cephalosporins and carried bla_CTX-M-15. (4) Conclusions: Our findings contribute to understanding the occurrence and pathogenicity of hybrid UPEC strains, which may cause more severe infections.

Comparative genome and evolution analysis of the locus of enterocyte effacement from enteropathogenic Escherichia coli Deng and its transcriptional response to ciprofloxacin

PURPOSE

In this study, we aimed to investigate the genomic characteristics and evolution of pathogenicity islands of an enteropathogenic Escherichia coli (EPEC) strain, and to obtain a transcriptional profile of EPEC under different concentrations of ciprofloxacin using microarray analysis.

METHODOLOGY

The complete EPEC Deng genome was sequenced and compared to genomes of 12 previously sequenced E. coli strains. A 180 min time course experiment was performed in which the effect of ciprofloxacin on EPEC Deng growth was evaluated. Microarray profiling was used to study the effect of varying ciprofloxacin pressure on genome-wide transcriptional expression. Differential expression of the genes identified using microarray data was confirmed using real-time quantitative reverse transcriptase PCR (RTQ). Target gene-defective recombineering strains were created to investigate the influence of the grlA gene on ciprofloxacin susceptibility.

RESULTS

Genomic comparisons revealed a close phylogenic relationship between EPEC Deng and E. coli strains O111_H_11128 and O26_H11_11368, with low genetic diversity among their type III secretion system genes and typically genetic variation in the map, tir, eae and espA genes of EPEC. It is noteworthy that 21 genes were down-regulated at all time points examined in the group exposed to 2 µg ml^-1 of ciprofloxacin. A grlA-mutant derivative with increased susceptibility to ciprofloxacin was discovered.

CONCLUSIONS

The present findings provide an overview of the phylogenetic characteristics of EPEC Deng and its transcriptional response to ciprofloxacin, further suggesting that GrlA may play a clinically important role in EPEC responses to ciprofloxacin.

Anti-Inflammatory and Antimicrobial Effects of a Novel Herbal Formulation (WSY-1075) in a Chronic Bacterial Prostatitis Rat Model

PURPOSE

The aim of this study was to investigate the anti-inflammatory and anti-oxidative effects of a multi-herbal formula known as WSY-1075 in the treatment of chronic bacterial prostatitis in a rat model.

MATERIALS AND METHODS

Experimental chronic bacterial prostatitis was induced in 32 Wistar rats by instillation of a bacterial suspension (Escherichia coli, 10⁸ colony-forming units [CFU]/mL) into the prostatic urethra. After the induction of prostatitis, the rats were randomly divided into one of 4 treatment groups: control (n=8), ciprofloxacin (n=8), WSY-1075 (400 mg/kg) (n=8), and WSY-1075 (400 mg/kg)+ciprofloxacin (n=8). After 4 weeks of treatment, microbiological data from prostate tissue cultures, level of prostatic pro-inflammatory cytokines (tumor necrosis factor-α [TNF-α], interleukin [IL]-6, and IL-8), anti-oxidant effects (superoxide dismutase [SOD]), and histological findings were noted.

RESULTS

The WSY-1075, ciprofloxacin, and WSY-1075+ciprofloxacin groups showed fewer CFUs in prostate tissue cultures than the control group. The WSY-1075, ciprofloxacin and WSY-1075+ciprofloxacin groups showed statistically significantly lower levels of the pro-inflammatory cytokines TNF-α, IL-6, and IL-8 than the control group. SOD levels in the WSY-1075, ciprofloxacin and WSY-1075+ciprofloxacin groups were significantly higher than in the control group.

CONCLUSIONS

This study found that WSY-1075 had anti-microbial effects, anti-inflammatory effects, and anti-oxidative effects in a chronic bacterial prostatitis rat model. We expect the WSY-1075 may be useful for the clinical treatment of chronic bacterial prostatitis.

Bacterial Prostatitis: Bacterial Virulence, Clinical Outcomes, and New Directions

Four prostatitis syndromes are recognized clinically: acute bacterial prostatitis, chronic bacterial prostatitis, chronic prostatitis/chronic pelvic pain syndrome, and asymptomatic prostatitis. Because Escherichia coli represents the most common cause of bacterial prostatitis, we investigated the importance of bacterial virulence factors and antimicrobial resistance in E. coli strains causing prostatitis and the potential association of these characteristics with clinical outcomes. A structured literature review revealed that we have limited understanding of the virulence-associated characteristics of E. coli causing acute prostatitis. Therefore, we completed a comprehensive microbiological and molecular investigation of a unique strain collection isolated from healthy young men. We also considered new data from an animal model system suggesting certain E. coli might prove important in the etiology of chronic prostatitis/chronic pelvic pain syndrome. Our human data suggest that E. coli needs multiple pathogenicity-associated traits to overcome anatomic and immune responses in healthy young men without urological risk factors. The phylogenetic background and accumulation of an exceptional repertoire of extraintestinal pathogenic virulence-associated genes indicate that these E. coli strains belong to a highly virulent subset of uropathogenic variants. In contrast, antibiotic resistance confers little added advantage to E. coli strains in these healthy outpatients. Our animal model data also suggest that certain pathogenic E. coli may be important in the etiology of chronic prostatitis/chronic pelvic pain syndrome through mechanisms that are dependent on the host genetic background and the virulence of the bacterial strain.

Relationship of biofilm formation and different virulence genes in uropathogenic Escherichia coli isolates from Northwest Iran

Background and objectives: The Escherichia coli (E. coli) bacterium is one of the main causative agents of urinary tract infections (UTI) worldwide. The ability of this bacterium to form biofilms on medical devices such as catheters plays an important role in the development of UTI. The aim of the present study was to investigate the possible relationship between virulence factors and biofilm formation of E. coli isolates responsible for urinary tract infection.

Materials and methods: A total of 100 E. coli isolates isolated from patients with UTI were collected and characterized by routine bacteriological methods. In vitro biofilm formation by these isolates was determined using the 96-well microtiter-plate test, and the presence of fimA, papC, and hly virulence genes was examined by PCR assay. Data analysis was performed using SPSS 16.0 software.

Results: From 100 E. coli isolates isolated from UTIs, 92% were shown to be biofilm positive. The genes papC, fimA, and hly were detected in 43%, 94% and 26% of isolates, respectively. Biofilm formation in isolates that expressed papC, fimA, and hly genes was 100%, 93%, and 100%, respectively. A significant relationship was found between presence of the papC gene and biofilm formation in E. coli isolates isolated from UTI (P<0.01), but there was no statistically significant correlation between presence of fimA and hly genes with biofilm formation (P<0.072, P<0.104).

Conclusion: Results showed that fimA and hly genes do not seem to be necessary or sufficient for the production of biofilm in E. coli, but the presence of papC correlates with increased biofilm formation of urinary tract isolates. Overall, the presence of fimA, papC, and hly virulence genes coincides with in vitro biofilm formation in uropathogenic E. coli isolates.

Escherichia coli isolates from patients with bacteremic urinary tract infection are genetically distinct from those derived from sepsis following prostate transrectal biopsy

BACKGROUND

Transrectal ultrasound-guided (TRUS) prostate biopsy is a very common procedure that is generally considered relatively safe. However, severe sepsis can occur after TRUS prostate biopsies, with Escherichia coli being the predominant causative agent. A common perception is that the bacteria that cause post-TRUS prostate biopsy infections originate in the urinary tract, but this view has not been adequately tested. Yet other authors believe on the basis of indirect evidence that the pathogens are introduced into the bloodstream by the biopsy needle after passage through the rectal mucosa.

METHODS

We compared E. coli isolates from male patients with bacteremic urinary tract infection (B-UTI) to isolates of patients with post prostate biopsy sepsis (PPBS), in terms of their sequence types, determined by multi-locus sequence typing (MLST) and their virulence markers.

RESULTS

B-UTI isolates were much richer in virulence genes than were PPBS isolates, supporting the hypothesis that E. coli causing PPBS derive directly from the rectum. Sequence type 131 (ST131) strains and related strain from the ST131 were common (>30%) among the E. coli isolates from PPBS patients as well as from B-UTI patients and all these strains expressed extended spectrum beta-lactamases.

CONCLUSIONS

Our finding supports the hypothesis that E. coli causing PPBS derive directly from the rectum, bypassing the urinary tract, and therefore do not require many of the virulence capabilities necessary for an E. coli strain that must persist in the urinary tract. In light of the increasing prevalence of highly resistant E. coli strains, a new approach for prevention of PPBS is urgently required.

Preventive effect of ginsenoid on chronic bacterial prostatitis

Empirical antibiotic therapy is the preferred primary treatment modality for chronic bacterial prostatitis (CBP). However, this method of treatment has a low success rate and long-term therapy may result in complications and the appearance of resistant strains. Therefore a new alternative method for the prevention of CBP is necessary. There are several reports that ginsenoid has a preventive effect on urinary tract infection (UTI). To evaluate the preventive effect of ginsenoid on CBP compared to conventional antibiotics, we carried out an experiment in a rat model of the disease. Four groups of adult male Wistar rats were treated with the following medications: (1) control (no medication), (2) ciprofloxacin, (3) ginsenoid, and (4) ciprofloxacin/ginsenoid. All medications were given for 4 weeks, and then we created a CBP model in the animals by injecting an Escherichia coli Z17 (O2:K1;H(-)) suspension into the prostatic urethra. After 4 weeks, results of microbiological cultures of prostate and urine samples, as well as histological findings of the prostate in each group were analyzed. The microbiological cultures of the prostate samples demonstrated reduced bacterial growth in all experimental groups compared with the control group. Histopathological examination showed a significantly decreased rate of infiltration of inflammatory cells into prostatic tissue and decreased interstitial fibrosis in the ginsenoid group compared with the control group. Inhibition of prostate infection was greater in the group receiving both ginsenoid and antibiotic than in the single-medication groups. Although the findings of this study suggest a preventive effect of ginsenoid, preventive methods for CBP are still controversial.

Genome-wide transcriptome analysis of fluoroquinolone resistance in clinical isolates of Escherichia coli

OBJECTIVES

Coincident with their worldwide use, resistance to fluoroquinolones in Escherichia coli has increased. To identify the gene expression profiles underlying fluoroquinolone resistance, we carried out genome-wide transcriptome analysis of fluoroquinolone-sensitive E. coli.

METHODS

Four fluoroquinolone-sensitive E. coli and five fluoroquinolone-resistant E. coli clinical isolates were subjected to complementary deoxyribonucleic acid microarray analysis. Some upregulated genes' expression was verified by real-time polymerase chain reaction using 104 E. coli clinical isolates, and minimum inhibitory concentration tests were carried out by using their transformants.

RESULTS

A total of 40 genes were significantly upregulated in fluoroquinolone-resistant E. coli isolates (P < 0.05). The expression of phage shock protein operons, which are involved in biofilm formation, was markedly upregulated in our profile of fluoroquinolone-resistant E. coli. One of the phage shock protein operons, pspC, was significantly upregulated in 50 fluoroquinolone-resistant E. coli isolates (P < 0.0001). The expression of type I fimbriae genes, which are pilus operons involved in biofilm formation, were markedly downregulated in fluoroquinolone-resistant E. coli. Deoxyribonucleic acid adenine methyltransferase (dam), which represses type I fimbriae genes, was significantly upregulated in the clinical fluoroquinolone-resistant E. coli isolates (P = 0.007). We established pspC- and dam-expressing E. coli transformants from fluoroquinolone-sensitive E. coli, and the minimum inhibitory concentration tests showed that the transformants acquired fluoroquinolone resistance, suggesting that upregulation of these genes contributes to acquiring fluoroquinolone resistance.

CONCLUSIONS

Upregulation of psp operones and dam underlying pilus operons downregulation might be associated with fluoroquinolone resistance in E. coli.

Acute Escherichia coli prostatitis in previously health young men: bacterial virulence factors, antimicrobial resistance, and clinical outcomes

OBJECTIVES

To investigate clinical outcomes, bacterial virulence factors, and antimicrobial resistance in E. coli from young men presenting with acute bacterial prostatitis.

METHODS

Initial E. coli isolates from previously healthy young men with no factors compromising urinary tract anatomy or function were tested for virulence-associated genes by polymerase chain reaction (PCR) assays, phylogenetic grouping by triplex polymerase PCR, and antibiotic resistance.

RESULTS

All 18 patients responded to treatment, including 2 who required long-term therapy. E. coli were allocated to phylogenetic groups B2 (13 strains) and D (5 strains). Prostatitis isolates belonged to clones mainly represented by extraintestinal pathogenic E. coli (ExPEC) and preferentially uropathogenic E. coli and displayed marked accumulation of virulence genes (hly, cdt1, clb, pap, sfa/foc, fyuA, iroN, kpsMT(II), and traT) characteristic of highly virulent ExPEC. All phylogenetic group B2 strains coded for at least 1 toxin with carcinogenic potential (Colibactin, cytolethal distending toxins, or cytotoxic necrotizing factor). In contrast to their accumulation of virulence-associated traits, prostatitis strains were sensitive to standard antibiotics.

CONCLUSIONS

The phylogenetic background and accumulation of an exceptional repertoire of extraintestinal pathogenic virulence-associated genes indicate that these E. coli strains belong to a highly virulent subset of uropathogenic variants. In contrast, antibiotic resistance was minimal in these E. coli strains from previously healthy, young outpatients.

A systematic review of outbreak and non-outbreak studies of extraintestinal pathogenic Escherichia coli causing community-acquired infections

A systematic review of outbreak and non-outbreak studies of infections caused by extraintestinal pathogenic Escherichia coli (ExPEC) was conducted. This review examines the epidemiology, seasonality, source or mode of transmission, and temporal changes, based on E. coli serogroup, in ExPEC causing sporadic vs. outbreak-associated infections. Twelve outbreak and 28 non-outbreak studies were identified. The existence of ExPEC outbreaks was well supported. Three of four outbreak reports indicated peak periods during the winter months. Serogroups associated with outbreak infections ranged from 1% to 26% (average 11·4%) vs. (range 1-15%, average 3·5%) for serogroups associated with sporadic infections; the distribution of serogroups also differed for outbreak and non-outbreak infections. Study authors indicated that the outbreaks may have resulted from foodborne transmission, but direct evidence was unavailable. This review provides evidence that the epidemiology of endemic vs. epidemic ExPEC infections differs; however, study reporting quality limited epidemiological inferences.

Safety and efficacy of levofloxacin 750 mg for 2 weeks or 3 weeks compared with levofloxacin 500 mg for 4 weeks in treating chronic bacterial prostatitis

OBJECTIVE

To compare the safety and efficacy of levofloxacin 750 mg QD for 2 weeks or levofloxacin 750 mg QD for 3 weeks to levofloxacin 500 mg QD for 4 weeks in treating chronic bacterial prostatitis (CBP).

RESEARCH DESIGN AND METHODS

This was a randomized, multicenter, double-blind, noninferiority study. The primary efficacy end point was investigator assessment of clinical success in the modified intent-to-treat (mITT) population at post-therapy. National Institutes of Health-Chronic Prostatitis Symptom Index (NIH-CPSI) scores were utilized to evaluate subject-reported responses post-therapy.

RESULTS

A total of 241 subjects were enrolled. At post-therapy (test of cure [TOC]), clinical success rates for levofloxacin-treated subjects (750 mg QD for 3 weeks [64.9%, 48/74]) were noninferior to 500 mg QD for 4 weeks (69.3%, 52/75: 95% CI, -19.5%, 10.6%). Success rates with levofloxacin 750 mg QD for 2 weeks (63.0%, 46/73) were not noninferior to therapy with levofloxacin 500 mg QD for 4 weeks (95% CI, -21.5%, 8.9%) at TOC. At 3 and 6 months post-therapy, clinical success rates were clinically higher for the 500-mg, 4-week treatment group, and statistical analysis demonstrated both groups were not noninferior to standard therapy with levofloxacin 500 mg (95% CI, -32.5%, -0.6% for both 750-mg groups at 6 months). NIH-CPSI scores showed similar trends. Overall, adverse event (AE) rates were similar for the three treatment groups; however, discontinuation of therapy due to AEs was higher with the 750-mg dose (p = 0.02, and p = 0.13 for 750 mg, 2 weeks and 750 mg, 3 weeks versus 500 mg for 4 weeks, respectively). The main limitation of this study was that no bacterial cultures were required.

CONCLUSIONS

Higher doses for shorter durations were determined to be no worse than standard therapy with levofloxacin 500 mg for a longer duration at the TOC visit. However, at the 6-month follow-up visit, the levofloxacin 750-mg dose administered for either 2 weeks or 3 weeks was inferior to the standard therapy, suggesting that a longer duration of treatment may help extend the relapse-free interval in patients with CBP.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov, nct00402688.

A multiplex PCR method to detect 14 Escherichia coli serogroups associated with urinary tract infections

Urinary tract infections (UTIs) are one of the most common bacterial infections and are predominantly caused by uropathogenic Escherichia coli (UPEC). E. coli strains belonging to 14 serogroups, including O1, O2, O4, O6, O7, O8, O15, O16, O18, O21, O22, O25, O75 and O83, are the most frequently detected UPEC strains in a diverse range of clinical urine specimens. In the current study, the O-antigen gene clusters of E. coli serogroups O1, O2, O18 and O75 were characterized. A multiplex PCR method based on O-antigen-specific genes was developed for the simultaneous detection of all 14 E. coli serogroups. The multiplex PCR method was shown to be highly specific and reproducible when tested against 186 E. coli and Shigella O-serogroup reference strains, 47 E. coli clinical isolates and 10 strains of other bacterial species. The sensitivity of the multiplex PCR method was analyzed and shown to detect O-antigen-specific genes in samples containing 25 ng of genomic DNA or in mock urine specimens containing 40 colony-forming units (CFUs) per ml. Five urine specimens from hospital were examined using this multiplex PCR method, and the result for one sample was verified by the conventional serotyping methods. The multiplex PCR method developed herein can be used for the detection of relevant E. coli strains from clinical and/or environmental samples, and it is particularly useful for epidemiologic analysis of urine specimens from patients with UTIs.

Virulence Traits in Escherichia Coli Strains Isolated from Outpatients with Urinary Tract Infections

This study aims to characterize phenotypic and genotypic virulence traits in Escherichia coli strains, isolated from outpatients with urinary tract infections, comparing with those obtained from inpatients. Information on the pathogenic behavior of the uropathogenic strains was obtained by monitoring different biological properties, such as autoagglutination, hemagglutination, adhesiveness to and invasion of human bladder (HT1376) cells, biofilm formation, phylogenetic grouping, and virulence-related genes. The results show similar behavior in the two groups concerning autoagglutination, hemagglutination, and biofilm formation. None of the strains examined was invasive. However, in strains from outpatients there was an increased adhesion to HT1376 cells compared with clinical strains, a significant higher presence of genes codifying for adhesins and cell protection factors, and a lower proportion of strains belonging to B1 group. These findings add further information on the pathogenic traits of community E. coli, since strains isolated from the outpatients' group were differently “armed” in comparison with those of clinical cases, and more suitable to infect healthy individuals.

Molecular epidemiology of uropathogenic Escherichia coli

Escherichia coli is the most common cause of complicated as well as uncomplicated urinary tract infections (UTIs). Most of these uropathogenic E. coli (UPEC) strains exhibit certain virulence factors (VFs), including adhesins, iron uptake systems, synthesis of cytotoxins, and specific O:K:H serotypes. Molecular epidemiological studies of UPEC have contributed to the discovery of uropathogenic VFs, to an understanding of the pathogenesis of UTIs as ascending infections, and to the clarification of genetic linkages between different virulence genes such as pathogenicity islands (PAIs), which are one of the mechanisms for horizontal VF gene transfers between the same or related species. Uropathogenic VFs not only play an important role individually but also work cooperatively in a fine-tuned manner with coordinated regulation and expression.

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.

Ultrastructural stages of biofilm development of Escherichia coli on urethral catheters and effects of antibiotics on biofilm formation

OBJECTIVES

Biofilm formation on biomaterials by various kinds of bacteria renders the infection chronic, and the bacteria can become resistant to the immune system and antibiotics. Developmental biofilm stages of Escherichia coli on urethral catheters have not yet been thoroughly demonstrated. We aimed to show biofilm formation of E. coli on urethral catheters, and the effects of various antibacterial agents on this formation using scanning electron microscopy.

METHODS

Using urine infected with uropathogenic E. coli type O4 (10(5) to 10(6) colony forming units/mL), biofilm was formed on latex/silicone balloon catheters in a modified Robbin's device. The study included an infected-only group and four antibiotic study groups (ciprofloxacin, cefuroxime, gentamicin, and trimethoprim). The catheters were infused with the antibiotic solutions once before placement in the modified Robbin's devices. Ten 5-mm catheter samples were taken for all groups on the first, fourth, and seventh days. The 4 and 12-hour and 2-day samplings were also taken from the infected-only group. The catheter samples were evaluated by scanning electron microscopy and given scores according to the level of formation.

RESULTS

The biofilm layers emerged between 4 and 12 hours after infection in the infected-only group and had developed completely between 12 and 24 hours. The antibiotics, especially cefuroxime, significantly delayed this process for up to 4 days. However, the biofilm had developed completely in almost all catheter samples after 4 to 7 days.

CONCLUSIONS

Biofilm of E. coli on urethral catheters had completed their maturation at 12 to 24 hours. For short-term urethral catheterization, a single dose of antibiotic can delay the development of biofilm for up to 4 days but eventually cannot prevent it.

Escherichia coli isolates associated with uncomplicated and complicated cystitis and asymptomatic bacteriuria possess similar phylogenies, virulence genes, and O-serogroup profiles

The genetic and serological characteristics of Escherichia coli isolates from patients with uncomplicated cystitis (UC), complicated cystitis (CC), and complicated asymptomatic bacteriuria (CASB) were determined. Phylogenetic group B2 was predominant in all categories. The prevalences of 14 out of 18 virulence factor genes were similar among the three categories, while pap, iha, ompT, and PAI were more frequently seen in isolates associated with UC than CC or CASB.

Increased biofilm formation in Escherichia coli isolated from acute prostatitis

Using crystal violet binding assay, we examined the potential for biofilm formation in 194, 76 and 107 isolates from urine of patients with uncomplicated acute cystitis, pyelonephritis and prostatitis, respectively. The prostatitis isolates showed significantly higher optical density (OD) values compared with cystitis and pyelonephritis isolates (OD(540): 0.82, 0.29 and 0.43, respectively, P<0.0001). Similarly, strains of serotypes O4 and O22, which were commonly isolated from prostatitis, exhibited significantly higher OD values than did other strains. Furthermore, when the 21 prostatitis isolates were examined for expression of curli fimbriae, eight of 12 strains with a high OD value, but only three of nine with a low OD value, expressed curli fimbriae (P=0.0195). These results suggest an association between acute bacterial prostatitis and biofilm formation.

Subtyping of uropathogenic Escherichia coli according to the pathogenicity island encoding uropathogenic-specific protein: Comparison with phylogenetic groups

BACKGROUND

Phylogenetic analysis has been used widely to characterize extraintestinal pathogenic Escherichia coli in molecular epidemiological studies. We have recently reported a putative pathogenicity island (PAI), carrying uropathogenic-specific protein (usp) and a unique mosaic structure of small open reading frames following usp, providing four subtypes of PAIusp classified from their sequential patterns.

METHODS

A total of 427 E. coli isolates from uncomplicated urinary tract infections (194 cystitis, 76 pyelonephritis, and 107 prostatitis) and 50 fecal isolates were examined for phylogenetic grouping and PAIusp subtyping as well as the prevalence of virulence factors (VF) and O serogroups.

RESULTS

Both phylogenetic group B2 and usp-positive strains were equally predominant in cystitis, pyelonephritis and prostatitis (B2, 80.9%, 86.8%, and 86.9%; usp, 79.4%, 93.4%, and 88.8%, respectively). Furthermore, each PAIusp subtype was shown to be closely associated with several VF genes as well as several common O serogroups of uropathogenic E. coli.

CONCLUSIONS

In molecular epidemiological studies, PAIusp subtyping will provide additional informative findings of E. coli strains belonging to phylogenetic group B2.

Detection of Escherichia coli 16S RNA and cytotoxic necrotizing factor 1 gene in benign prostate hyperplasia

OBJECTIVES

Inflammation and occasionally necrosis is observed in the prostate tissue from patients with benign prostate hyperplasia (BPH). The etiology of prostatic inflammation/necrosis is unknown, but bacteria may be involved.

MATERIALS AND METHODS

Retrospective analysis of archival prostate tissue samples collected during 1982-1997 was undertaken. Three hundred fifty-two specimens from patients with BPH obtained via transurethral resection of prostate (TURP) were studied for the presence of Escherichia coli 16S RNA and E. coli virulence factor genes: cytotoxic necrotizing factor (cnf1), alpha-hemolysin (hly), an autotransported protein (sat), and P fimbriae (papC).

RESULTS

E. coli 16S RNA was detected in 12 (3%) samples and cnf1 gene in six (1.5%) samples, with two samples being positive for both markers. hly, sat, papC genes were not detected. Of 6 cnf1-positive samples, severe inflammation and necrosis were present in four and three samples, respectively. Of eight E. coli-positive/cnf1-negative samples, five showed signs of severe inflammation and two showed severe necrosis.

CONCLUSIONS

A small proportion of patients with BPH undergoing TURP are positive for E. coli 16S RNA and cnf1 gene in the prostate tissue. Further studies are needed to show that particular E. coli genotypes are involved in the development of prostatic inflammation/necrosis in BPH.

Mouse model for acute bacterial prostatitis in genetically distinct inbred strains

OBJECTIVES

Prostatitis is a common urologic disease seen in adult men. As many as 50% of men will experience an episode of prostatitis in their lifetime, and 2% to 3% of men will have bacterial prostatitis. Because the pathogenic mechanisms of prostatitis remain unclear, we developed a reproducible mouse model of bacterial prostatitis in which to study the etiology and host factors associated with infection susceptibility.

METHODS

Male BALB/c, C3H/HeJ, C3H/HeOuJ, C57BL/6J, and (BALB/c x C3H/HeJ)F1 mice 13 weeks old were inoculated intraurethrally with 2 x 10(6) or 2 x 10(8) Escherichia coli. Control mice were inoculated with phosphate-buffered saline. The animals were killed at 5 days after inoculation to assess the intensities of the bladder and prostate infections.

RESULTS

Significant bladder or prostate infections were not present in the BALB/c, C57BL/6J, or (BALB/c x C3H/HeJ)F1 mice at either inoculum dose. In contrast, both C3H/HeJ and C3H/HeOuJ mice developed high bladder infections and severe, acute prostatitis at both doses. Control mice infected with phosphate-buffered saline had no bladder or prostate infections. The P values were less than 0.01 for the comparison of bladder and prostate colony-forming units between C3H/HeJ or C3H/HeOuJ and BALB/c, C57BL/6J, or F1 mice.

CONCLUSIONS

The strain-dependent differences in susceptibility indicate that genetic factors may play a major role in the etiology of bacterial prostatitis. Because F1 mice did not develop significant bladder and prostate infections, similar to the BALB/c parents, it appears that infection susceptibility is a recessive trait. The availability of this model will allow us to investigate the immunology, genetics, and histopathologic features of bacterial infection of the prostate.

Phylogenetic and pathotypic comparison of concurrent urine and rectal Escherichia coli isolates from men with febrile urinary tract infection

Among men with febrile urinary tract infection (FUTI), whether the host's fecal flora is the source for the urine strain ("fecal-urethral" hypothesis), and whether pathogenesis is driven by prevalence versus special pathogenicity, are unknown. Accordingly, pretherapy urine isolates from 65 men with FUTI were compared with concurrent rectal isolates from the same hosts according to serotype, genomic profile, phylogenetic group, and virulence genotype. The host's multiple rectal colonies included only the urine clone in 25% of subjects, the urine clone plus additional clones in 22%, and only nonurine clones in 54%. Compared with the 67 unique rectal clones, the 65 urine isolates were significantly enriched for phylogenetic group B2, virulence-associated serotypes, and specific virulence genes and contained more virulence genes (median, 10 versus 6: P < 0.001). In multivariable models, phylogenetic group B2, hlyD (hemolysin), cnf1 (cytotoxic necrotizing factor), iroN (siderophore receptor), ompT (outer membrane protease), and malX (pathogenicity island marker) most strongly predicted urine source. These findings challenge the fecal-urethral and prevalence hypotheses for FUTI pathogenesis and instead strongly support the possibility of alternate infection routes in some men and the special pathogenicity hypothesis. They also identify specific bacterial traits as potential targets for anti-FUTI interventions.

Synergistic effect between catechin and ciprofloxacin on chronic bacterial prostatitis rat model

BACKGROUND

Chronic bacterial prostatitis (CBP) is the most common urological disease in adult men. Antibiotic therapy is the gold standard of treatment. However, long-term therapy resulted in many side-effects and bacterial resistance. Because of these reasons, we need new treatment modality that could replace traditional antibiotic therapy. Catechin, an extract of green tea, has antimicrobial effect against various bacteria and synergy effect to antibiotics. We evaluate the synergistic effects of catechin on the treatment of CBP in an animal model.

METHODS

An experimental CBP model was induced in 70 male Wistar rats by instillation of 0.2 mL bacterial suspension (E-coli Z17, O2:K1:H-) containing 1 x 10(8) CFU/mL into the prostatic urethra. Microbiologically and histologically proven CBP model was demonstrated in 58.6% (41 of 70) of the rats after 4 weeks of bacterial instillation. The 41 rats demonstrating CBP were randomly divided into four groups; the control, catechin, ciprofloxacin and catechin with ciprofloxacin groups. All drug treatments were conducted over a period of 2 weeks. After treatment, the results were analyzed with microbiological cultures and histological findings of the prostate and urine samples to compare each group.

RESULTS

Microbiological cultures and histological findings of the prostate and urine samples demonstrated reduced bacterial growth and improved inflammatory responses in all three experimental groups compared with the control group. The catechin group showed coherent trends of decrease in bacterial growth and improvements in prostatic inflammation compared with the control group, but not to a statistically significant degree (P > 0.05). However, the ciprofloxacin and catechin with ciprofloxacin groups showed statistically significant decreases in bacterial growth and improvements in prostatic inflammation compared with the control group (P < 0.05). The catechin with ciprofloxacin group showed a statistically significant decrease in bacterial growth and improvements in prostatic inflammation compared with the ciprofloxacin group (P < 0.05).

CONCLUSIONS

These results suggest that catechin may be an effective material in CBP treatment. Particularly, combination treatment of catechin and ciprofloxacin has synergistic effect. Therefore, we suggest that the combination of catechin and ciprofloxacin may be effective in treating CBP with a higher success rate.

Distribution and genetic association of putative uropathogenic virulence factors iroN, iha, kpsMT, ompT and usp in Escherichia coli isolated from urinary tract infections in Japan

PURPOSE

Many virulence factors (VFs) have been reported in uropathogenic Escherichia coli. Recently we found a putative uropathogenic island including a gene encoding uropathogenic specific protein (USP). We have described the association between usp and other VFs reported previously. In the current study we examined epidemiological associations among 5 putative uropathogenic VFs.

MATERIALS AND METHODS

In 427 E. coli strains, including 194, 76 and 107 isolates from patients with cystitis, pyelonephritis and prostatitis, respectively, and 50 isolates from the stool of healthy adults, we detected catecholate siderophore receptor (iroN), iron regulated gene A homologue adhesin (iha), group II capsule (kpsMT) and outer membrane protease T (ompT) by polymerase chain reaction assays. We analyzed their distribution and genetic association.

RESULTS

Relative prevalence ratios of iroN, iha, kpsMT, ompT and usp were 2.0 to 4.3 times more frequently in urinary tract infection isolates than in fecal isolates. Isolates from prostatitis were frequently associated with iroN, ompT and usp, whereas isolates from pyelonephritis frequently harbored usp. Together with iroN and iha we noted S-/F-fimbriae and iucD aerobactin (OR 95.9 and 187.2), while usp showed a close association with kpsMT and ompT (OR 38.3 and 38.4, respectively).

CONCLUSIONS

Of the putative uropathogenic VFs examined iroN, iha, kpsMT, ompT and usp were frequently associated with urinary tract infection. Especially iroN and usp were most frequently associated with prostatitis. Some VFs were closely associated with a specific anatomical site of infection. Strong associations among several VFs might indicate not only well-known genetic linkages, but also unknown functional linkages among these VFs.

Effects of androgen deprivation on chronic bacterial prostatitis in a rat model

BACKGROUND

Many attempts have been made to improve the treatment success rate of chronic bacterial prostatitis (CBP). However, no treatment modality has achieved complete cure. The growth and development of the prostate is under direct hormonal control, and it is possible that prostatitis may be directly influenced by its hormonal milieu in a similar fashion to benign prostatic hyperplasia and prostate cancer. Therefore, the effects of androgen deprivation on the treatment of CBP were investigated in rats.

METHODS

Experimental CBP was induced in one hundred, male Wistar rats by instillation of bacterial suspension (Escherichia coli Z17, O2: K1: H-) containing 1 x 10(8) CFU/ microL into the prostatic urethra. Microbiologically and histologically proven CBP was demonstrated in 62% (62 of 100) of the rats after 4 weeks of bacterial instillation. The 62 rats demonstrating CBP were randomly divided into five groups: control; castration; finasteride; estrogen; and levofloxacin groups. All drug treatments were conducted over a period of 4 weeks.

RESULTS

Microbiological cultures and histological findings of the prostate and urine samples demonstrated reduced bacterial growth and improved inflammatory responses in all four experimental groups compared with the control group. The castration and estrogen groups showed coherent trends of decrease in bacterial growth and improvements in prostatic inflammation compared with the control group, but not to a statistically significant degree (P > 0.05). However, the finasteride and levofloxacin groups did show statistically significant decreases in bacterial growth and improvements in prostatic inflammation compared with the control group (P < 0.05).

CONCLUSION

These results suggest that androgen deprivation is an effective modality in CBP treatment. In particular, the finasteride treatment reduced the severity of CBP in the animal model without reducing the systemic testosterone level. The combination of finasteride and levofloxacin maybe one of the effective treatment modalities for CBP.

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.

Antibacterial effect of intraprostatic zinc injection in a rat model of chronic bacterial prostatitis

High levels of prostatic zinc are associated with prostatic antimicrobial activities and are depressed in patients with chronic prostatitis. We investigated the inhibition of bacterial growth in the rat prostate with chronic prostatitis after intraprostatic injection of zinc and compared two different types of zinc delivery. Ninety male Wistar rats were used in the study. Experimental chronic bacterial prostatitis was induced by instillation of bacterial suspension (Escherichia coli 10(8) per ml) into the prostatic urethra. Animals were followed for 4 weeks and then injected intraprostatically with either 0.2 ml of zinc liposome (ZL) or zinc solution (ZS) (0.04 M zinc sulphate) or 0.2 ml of phosphate-buffered saline (PBS) for the controls. Ten rats in each group were sacrificed 4, 6 and 8 weeks after injection. The inhibition of inflammation and its consequences were analyzed microbiologically and histologically. Prostatic zinc concentrations were measured by inductively coupled plasma atomic emission spectrometry. Microbiological culture of the prostates demonstrated bacterial growth inhibition by the intraprostatic injection of zinc. The average infection rates and mean log(10) cfu/g of the zinc-treated groups were significantly lower than those of the controls. The histopathology showed resolving prostatitis in zinc-treated groups compared with the controls. Prostatic zinc levels were higher in the zinc-treated groups than in the controls 4 and 6 weeks after zinc injection (P<0.05). However, the ZL and ZS groups were found to be effectively identical in terms of prostatic zinc levels, bacterial cfu, and histological findings throughout the experiment period. The intraprostatic injection of zinc inhibited bacterial growth by increasing zinc levels in the rat prostatitis model. Our results suggest that the local application of zinc to the prostate may be a new treatment for chronic bacterial prostatitis at the point of its pathogenesis.

Structural and sequence diversity of the pathogenicity island of uropathogenic Escherichia coli which encodes the USP protein

A total of 321 uropathogenic Escherichia coli (UPEC) strains and 12 strains of E. coli isolated from stool samples of healthy individuals, which were previously shown to be positive in colony hybridization test using the usp (encoding for the uropathogenic-specific protein) DNA probe, were examined by PCR amplification to determine the size of the usp gene and the pathogenicity island (PI). Three types of size variation were observed for the usp gene and four types for the PI. Sequencing analysis of the PIs from seven representative strains (six UPEC and one from a normal healthy individual) revealed that the usp genes can be classified into two groups, each having different sequences in the 3'-terminal region. The peptides encoded by the three open reading frames (ORFs) downstream of usp had identical 23 amino acid residues in the C-terminal region. The subregion encoding these small ORFs has a mosaic structure constituted of six segments. The positions of these segments vary from strain to strain, and in some strains, two to four segments are deleted. This indicates that rearrangements occur frequently in this region and the mosaic arrangement apparently contributes to the size variation observed in the PCR examination of the usp genes and PIs.

Murine monoclonal antibodies against Escherichia coli O4 lipopolysaccharide and H5 flagellin

Two murine monoclonal antibodies (MAb), 2C5-F10 and 8D1-H10, reactive with Escherichia coli O4 and H5 antigens, respectively, were generated and characterized. Enzyme immunoassays and immunoblots demonstrated that MAb 2C5-F10 reacted specifically with lipopolysaccharide O antigen of E. coli O4 isolates, while MAb 8D1-H10 reacted with E. coli strains expressing H5 flagella.

Characterization of a putative virulence island in the chromosome of uropathogenic Escherichia coli possessing a gene encoding a uropathogenic-specific protein

This study was initiated to search for a homologue of the Vibrio cholerae zot gene in uropathogenic Escherichia coli (UPEC) using a specific DNA probe. The faint signal obtained at low stringency with some UPEC strains associated with prostatitis cases prompted us to examine UPEC strains by PCR using primers designed from the conserved regions of the proteins of the Zot group of putative NTPases containing the classical NTP binding motif. This led to the discovery of a DNA fragment in UPEC strains which hybridized with a probe designed from the PCR. Further analysis of this DNA fragment revealed an ORF which was designated as uropathogenic specific protein (Usp). The gene encoding Usp was 1038 bp long and codes for 346 amino acids with an appropriate SD sequence. Upstream and downstream analysis of usp revealed motifs of prokaryotic consensus promoters and three small ORFs with SDs and ribosome binding sites transcribed in the same direction of usp. The proximity of these set of genes in a specific area of the bacterial chromosome resembling a block of genes preferentially associated with UPEC coupled with the presence of a motif matching that of a Tn3 transposon family lead us to believe that this could be an hitherto unknown pathogenicity island.

Identification of S, F1C and three PapG fimbrial adhesins in uropathogenic Escherichia coli by polymerase chain reaction

S and F1C fimbrial adhesins often expressed by uropathogenic Escherichia coli are genetically homologous. A multiply primed polymerase chain reaction (PCR) was developed for discriminating the S (sfa) and F1C (foc) fimbrial operons. A total of 270 uropathogenic E coli strains and 80 fecal isolates were examined. PCR specifically detected the sfa and foc alleles in 105 (93%) of 113 sfa/foc+ strains by DNA hybridization. Furthermore, 87% of sfa+ uropathogenic E. coli simultaneously possessed the genes encoding the class III P fimbrial adhesin (prsG(J96)), alpha-hemolysin and cytotoxic necrotizing factor 1. Statistical analysis showed the class II P fimbrial adhesin (papG(IA2)) and F1C fimbria to be associated with high relative virulence in pyelonephritis and cystitis, respectively. The multiply primed PCR developed should be useful for assessing the contribution of the S and F1C fimbriae in the pathogenesis of urinary tract infections.

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.