Innate immunity of surfactant protein A and D in urinary tract infection with uropathogenic Escherichia coli

Objective To investigate the role of surfactant protein (SP) - A and SP - D in urinary tract infection mouse model, and evaluate the effects of SP-A and SP-D absence on urinary tract infection. Methods SP-A and SP-D double knockout (SP-A/D KO) mice were made. SP-A/D KO and wild-type (WT) C57BL/6 female mice were used for this study. The expression of SP-A and SP-D in kidney was detected by immunohistochemistry (IHC). The levels of p - p38 and p38 protein in kidneys were measured by Western blotting. Uropathogenic Escherichia coli or buffer was delivered into the bladder of female mice. At 24 and 48 h after inoculation, CFU of Escherichia coli in the kidney and urine of the treated and control mice were measured. Histological, cellular and molecular analysis were performed by several methods of H/E staining, IHC and Western blotting. The effects of SP-A and SP-D on bacterial growth were studied in vitro. Results SP-A and SP-D in kidney were located in the proximal tubules and collecting tubules. Compared with WT mice, infected SP - A/D KO mice with UPEC had higher CFU in kidneys and urine at 24 h and 48 h, increased inflammatory cells infiltration in kidneys（P＜0.05）. Compared with WT mice, SP - A/D KO mice had higher p38 MAPK phosphorylation levels in kidneys（P＜0.05）. Growth of Escherichia coli was greatly inhibited by both SP-A and SP-D（P＜0.05）. Conclusions Both SP-A and SP-D are expressed in kidney. SP-A and SP-D can attenuate UTI induced by UPEC which may be through inhibiting bacterial growth and modulating renal inflammation.     

Variable adherence of uropathogenic Escherichia coli to epithelial cells from women with recurrent urinary tract infection

The adherence of 74 Escherichia coli strains to vaginal and buccal epithelial cells from women with recurrent urinary tract infections was studied. The strains were isolated from the urine, vaginal introitus or anal mucosa of women with recurrent bacteriuria. Vaginal and anal isolates were judged to be associated with urinary tract infection if they had the same biotype and serotype as the strain isolated subsequently from the urine. Adherence levels of urinary and anal isolates, and vaginal isolates associated with urinary tract infection were similar for vaginal and buccal cells. Adherence of vaginal isolates not associated with urinary tract infection was significantly lower than adherence of urinary isolates for vaginal (p less than 0.001) and buccal (p less than 0.005) epithelial cells. A positive nonlinear correlation between vaginal and buccal adherence was observed for urinary (r equals 0.87, p less than 0.0001), vaginal (r equals 0.70, p less than 0.0005) and anal (r equals 0.32, p equals 0.047) isolates. Strains of O-serogroups commonly and less commonly associated with bacteriuria had similar adherence. The results suggest that adherence of vaginal isolates is associated with the ability to cause urinary tract infections. The strong correlation between vaginal and buccal cell receptivity suggests that susceptibility to such infections may be controlled by genotypic traits.     

Viable but nonculturable uropathogenic bacteria are present in the mouse urinary tract following urinary tract infection and antibiotic therapy

Involvement of the viable but nonculturable (VBNC) condition in recurrent urinary tract infections (UTIs) was investigated. VBNC bacteria are those which are alive but do not give rise to visible growth under nonselective growth conditions. Urine, bladder, and kidney samples collected over a 2-month period from BALB/c mice inoculated with the uropathogenic Escherichia coli strain J96 were examined to determine the level of culturable and viable bacteria. Urine from uninoculated mice was found to contain more viable than culturable bacteria. Inoculated mice had a transient increase in the level of culturable forms of the uropathogen in their urine, followed by a decrease to background levels; they also had multiple log higher levels of viable cells than culturable cells. The culturable pathogenic bacteria in mice that were inoculated and received antibiotic treatment dropped to undetectable levels within 1 week. At 2 out of 12 subsequent time points spanning an additional 65 days, culturable forms of the inoculated pathogenic bacteria were recovered. Polymerase chain reaction (PCR) analysis confirmed that DNA from the inoculated bacteria was present in a sample that yielded no culturable bacteria. These data indicate that the inoculated uropathogenic E. coli was not eliminated by antibiotic therapy, and suggest that these bacteria may escape detection by current standard culturability assays because they are VBNC. Received: 24 March 2000 / Accepted: 11 September 2000     

Urinary tract infection associated with urinary calculi. 1. The significance of urinary tract infection in urinary calculi

We investigated 158 cases of urinary stones (infection stones 56, metabolic stones 102) with special reference to pyuria, bacteriuria, stone culture and urease activities of isolated bacteria. Abacterial pyuria was noted in 9 out of 49 (18%) infection stones and in 53 of 77 (69%) metabolic stones. Bacteriuria was noted in 79% of the infection stones and 26% of the metabolic stones. Sixty-seven percent of the infection stones were infected with mainly urea splitting bacteria such as Proteus mirabilis and Staphylococcus. Twenty-three percent of metabolic stones were also infected. Though E. coli, a non-urea splitting bacteria, was isolated most frequently from metabolic stones, urease positive Staphylococcus and Pseudomonas were also isolated. Bacteria within stones could be predicted on the basis of urine culture results of only 20 of 41 infection stones and 8 of 24 metabolic stones. These facts are useful for selection of some antibiotics in the treatment of urinary tract infections associated with urinary calculi. Urinary infections of urea splitting bacteria in infection stones are thought to be initial factors of stone formation and those of non-urea splitting bacteria are to be superimposed. However, urea splitting bacteria in metabolic stones may convert them into infection stones in future.     

Interaction of a pyelonephritogenic Escherichia coli strain with the tissue components of the mouse urinary tract

Immediately following the introduction of cells of a pyelonephritogenic strain of Escherichia coli (expressing both GS and MS adhesins) into the mouse bladder, these cells were found to be randomly distributed on the mucosal surfaces of both the bladder and the kidney. After 24 hr. these adherent bacterial cells had proliferated to form nonrandomly distributed adherent microcolonies on both mucosal surfaces and large masses within the renal ducts. Large amounts of amorphous material, which we presume to be of both host and bacterial origin, was associated with the bacterial microcolonies on the infected tissues. The removal of urinary slime and tissue coat material by acid pretreatment increased both the degree and the apparent avidity of bacterial adhesion to the bladder mucosa. The adherent bacteria on the bladder mucosa were radically elongated, while those on the kidney mucosa usually retained their short rod-like morphological characteristics. These data suggest that pyelonephritogenic bacteria adhere to mucosal surfaces in both the bladder and kidney, and proliferate to form adherent microcolonies within which bacteria are associated with large amounts of amorphous extracellular material.     

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.     

Idiopathic hypercalciuria associated with urinary tract infection in children

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

PCR检测泌尿系感染者尿大肠杆菌的探讨

目的：探讨聚合酶链反应（PCR）检测泌尿系感染患者尿内大肠杆菌的敏感性，方法：采用PCR及细菌培养的方法检测55例泌尿系感染患者尿内大肠杆菌，并对两种方法进行比较，结果：泌尿系感染症状反复发作而细菌培养常为阴性的患者，用PCR法检测常为阳性，PCR法检测阳性率明显高于细菌培养法，结论：采用PCR法检测泌尿系感染患者悄内大肠杆菌具有较高的敏感性。     

Escherichia coli strains causing urinary tract infection in uncircumcised infants resemble urosepsis-like adult strains

PURPOSE: Urinary tract infection (UTI) is the most frequent bacterial infection in infants younger than 90 days, and mainly affects uncircumcised males. In an attempt to unravel further the pathophysiology of UTI in this age group we used molecular methods to characterize Escherichia coli strains responsible for community acquired UTI in male and female infants and in adults. MATERIALS AND METHODS: A total of 79 E. coli isolates from uncircumcised male and female infants with UTI and no urinary tract abnormalities and 41 E. coli pyelonephritis isolates from nonhost compromised adults with bacteremia were characterized in terms of phylogenic relatedness and virulence factors. RESULTS: Males were infected by strains with a genetic background and virulence factors different from those affecting females but similar to those of adult pyelonephritis strains. CONCLUSIONS: Our molecular approach indicates that uncircumcised male infants are at higher risk for infection with highly virulent uropathogenic E. coli strains than are females. Preputial colonization may have a key role in the selection of such strains.     

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.     

The role of fimbriae of Escherichia coli in urinary tract infections]

The incidence of P-fimbriated E. coli from patients with pyelonephritis, cystitis and asymptomatic bacteriuria was 78.6%, 31.9% and 22.2%, respectively. Almost all of the P-fimbriated E. coli have also type-1 fimbriae. In the in vitro test, P-fimbriated E. coli attached to the uroepithelial cells in higher number than the type 1 fimbriated E. coli. The results of the adhesion inhibition test suggested that simultaneous presence of P-and type 1 fimbriae is the most significant virulence factor in urinary tract infections.     

尿路感染大肠埃希菌遗传种系分型及其耐药性的相关性探讨

目的探讨尿路感染大肠埃希菌不同遗传种系分型与耐药性的相关性。方法选取我院2013年1月至2014年3月分离的122株入院后48 h内尿路感染大肠埃希菌与108株入院后48 h后尿路感染大肠埃希菌作为临床研究对象,所有样本均选自尿路感染患者的中段尿,其中患者入院后48 h内分离到的尿路感染大肠埃希菌归为社区感染菌,患者入院后48 h后分离到的尿路感染大肠埃希菌归为医院感染菌,采用API20E肠杆菌科细菌鉴定试剂盒与梅里埃公司ATB微生物半自动分析仪鉴定菌株,用制片扩散法测定尿路感染大肠埃希菌的药物敏感性,对比不同遗传种系分型尿路感染大肠埃希菌耐药性、产超广谱β-内酰胺酶(extended spectrumβ-lactamases,ESBLs)率以及在医院感染与社区感染中的分布情况。结果根据试验结果可知,社区感染菌中与医院感染菌中均为D型比例最高,社区感染菌与医院感染菌的各遗传种系分型间无统计学差异(P0.05);230株大肠埃希菌中,共检出产酶菌株138株,单产ESBLs76株,单产AmpC酶34株,同时检出ESBLs和AmpC酶28株。230株大肠埃希菌对抗生素的耐药性为:对临床常用抗生素耐药性从高到低依次为:复方新诺明81.7%、哌拉西林76.7%、氨苄西林74.2%、氨苄西林舒巴坦61.7%、丁胺卡那霉素61.7%、头孢呋辛60.8%、头孢泊肟59.2%、氨曲南59.2%、哌拉新林他巴唑32.5%、头孢唑林68.3%、庆大霉素57.5%、头孢噻肟43.3%、头孢吡肟38.3%、头孢西丁33.3%、亚胺培南0.8%。单产头孢菌素酶(AmpC酶)、ESBLs及同时产ESBLs和AmpC酶的大肠埃希菌对除亚胺培南外的14种抗生素的耐药率均高于平均水平。结论医院感染大肠埃希菌D型与社区感染大肠埃希菌B1型的产ESBLs率最高,大肠杆菌D型对大部分抗菌药物高度耐药。