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Background Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) are one of the most common outpatient bacterial infections. Although bacterial and host factors are reported to be associated with UTI pathogenesis, little is known about the host age-related differences in bacterial virulence factors and antimicrobial susceptibility. Methods PCRs were carried out to detect K1 capsule antigen, 15 virulence factors, and phylogenetic groups in E. coli isolates. Antimicrobial susceptibility of selected agents was determined by the disk diffusion method. Isolates were divided into 6 groups based on their host age. Results The results showed that virulence factors PapGII, PapGIII, Cnf1, Aer, Usp, Iha, OmpT, HlyA, and Sat, had highest frequencies in the host age group 0–3. Phylogenetic group B2 dominated in our isolates (59.6%) followed by group D (20.7%). In addition, 77.4% of strains isolated from 0 to 3 age group belonged to phylogenetic group B2. Antimicrobial susceptibility tests showed that E. coli strains isolated were significantly more resistant to antimicrobial agents as host age increased. Phylogenetic group B2 isolates were more susceptible to antimicrobial agents, compared to A, B1, and D isolates. Conclusion We found E. coli isolated from elders were more resistant to antimicrobial agents and had less virulence factors.

Background: FimH adhesin is proposed to enhance Escherichia coli kidney infection by acting with PapGII adhesin, but genetic epidemiology study and animal study have not been widely conducted to confirm this hypothesis. Methods: We compared the prevalence of adhesin gene and their coexistent pattern between upper and lower urinary tract infection (UTI) strains. fimH mutant (EC114FM), papGII mutant (EC114PM) and fimH/papGII double mutant (EC114DM) were constructed from a pylonephritogenic strain (EC114). We compared among these strains for the infection ability in bladders and kidneys of female BALB/c mice challenged transurethrally with these bacteria and assessed 1, 3, and 7 days after inoculation. Results: Strains carrying fimH-only genotype were significantly more prevalent in lower UTI (P

Background/Purpose Helicobacter pylori is a human gastric pathogen. Antibiotic resistance of H. pylori has become a problem increasing the failure of H. pylori eradication. Therefore alternative approaches are required. The aim of this study was to evaluate the anti- H. pylori activity of Lactobacillus pentosus strain LPS16 and the mechanism of its killing effect. Methods The anti- H. pylori activity of LPS16 was determined by the disc diffusion test and time killing assay. High-performance liquid chromatography analysis was used to analyze the secreted compounds of LPS16. Sixty H. pylori strains isolated from different gastric diseases, having different antibiotic susceptibility were collected to analyze the spectrum of anti- H. pylori activity of LPS16. Adhesion ability of LPS16 to gastric epithelial cell lines was assayed by flow cytometry. Results The anti- H. pylori activity of LPS16 depended on the secreted component, and lactic acid mediated bactericidal activity against H. pylori . The bactericidal activity did not vary significantly among the strains isolated from different diseases having different antibiotic susceptibility. Moreover, LPS16 can adhere on gastric epithelial cell lines AKG and MKN45. Conclusion L. pentosus strain LPS16 had the broad-spectrum anti- H. pylori activity, suggesting that it can be used to prevent H. pylori infection.

Background Matrix-assisted laser desorption/ionization–time of flight mass spectrometry (MALDI-TOF MS) is a valuable method for rapid identification of blood stream infection (BSI) pathogens. Integration of MALDI-TOF MS and blood culture system can speed the identification of causative BSI microorganisms. Materials and methods We investigated the minimal microorganism concentrations of common BSI pathogens required for positive blood culture using BACTEC FX and for positive identification using MALDI-TOF MS. The time to detection with positive BACTEC FX and minimal incubation time with positive MALDI-TOF MS identification were determined for earlier identification of common BSI pathogens. Results The minimal microorganism concentrations required for positive blood culture using BACTEC FX were >10 7 –10 8 colony forming units/mL for most of the BSI pathogens. The minimal microorganism concentrations required for identification using MALDI-TOF MS were > 10 7 colony forming units/mL. Using simulated BSI models, one can obtain enough bacterial concentration from blood culture bottles for successful identification of five common Gram-positive and Gram-negative bacteria using MALDI-TOF MS 1.7–2.3 hours earlier than the usual time to detection in blood culture systems. Conclusion This study provides an approach to earlier identification of BSI pathogens prior to the detection of a positive signal in the blood culture system using MALDI-TOF MS, compared to current methods. It can speed the time for identification of BSI pathogens and may have benefits of earlier therapy choice and on patient outcome.

Background/Purpose(s) Gram-negative peritonitis is a frequent and serious complication of peritoneal dialysis (PD). No previous reports have focused on Klebsiella pneumoniae infection. The aim of this study was to investigate the host and bacterial factors associated with K. pneumoniae PD-related peritonitis. Methods We retrospectively studied K. pneumoniae PD-peritonitis cases treated at a university hospital in southern Taiwan during 1990–2011, and analyzed the clinical features and outcomes and bacterial characteristics of serotypes, hypermucoviscosity (HV), and virulence-associated genes such as wabG, uge, and rmpA in K. pneumoniae PD-related peritonitis. Fifty-four isolates of K. pneumoniae -related community-acquired urinary tract infection (UTI) and 76 morphologically different nonpathogenic K. pneumoniae isolates from healthy adults were used as controls. Results K. pneumoniae was the second most common monomicrobial pathogen causing Gram-negative PD-related peritonitis ( n = 13, 2.7%), and the most common pathogen involved in polymicrobial peritonitis (16/43, 37.2%) and associated with high catheter removal rate (7/16, 43.8%). Compared with Escherichia coli peritonitis cases, patients with monomicrobial K. pneumoniae peritonitis also had insignificantly higher incidence of sepsis/bacteremia [ n = 5 (38%), p = 0.11] and a higher mortality rate [ n = 3 (23%), p = 0.36]. The prevalence of K1/K2 ( n = 1, 7.7%) serotypes was low, but there was a higher prevalence of serotype K20 ( n = 3, 23.1%) in K. pneumoniae isolates derived from monomicrobial PD-related peritonitis compared with control groups. HV phenotype ( p rmpA genotype ( p = 0.007) were absent in the peritonitis group. Conclusion This is the first study focused on clinical and microbiological characteristics of K. pneumoniae PD-related peritonitis. K. pneumoniae was a common Gram-negative pathogen causing monomicrobial and polymicrobial PD-related peritonitis in southern Taiwan. The bacterial characteristics with low percentage of capsular serotype K1/K2, no significant HV, and absence of rmpA suggest a different pathogenesis in K. pneumoniae PD-related peritonitis compared with that in UTI and liver abscess.