Is There a Correlation between Helicobacter Pylori and Enterohepatic Helicobacter Species and Gallstone Cholecystitis?

BACKGROUND Cholecystitis is a common surgical condition. Recently, several authors have reported that DNA of bile tolerant Helicobacter spp. has been found in the human bile colonizing the biliary tract. The aim of this study was to evaluate the association between the presence of Helicobacter spp. and gallstone cholecystitis. METHODS In this case-control study, gallstones, bile, and gallbladder mucosa were collected from 25 patients without gallstone disease, 24 with acute cholecystitis, and 28 with chronic cholecystitis. The presence of Helicobacter pylori (H. pylori), Helicobacter bilis (H. bilis), Helicobacter hepaticus (H. hepaticus) , and Helicobacter pullorum (H. pullorum) were investigated by polymerase chain reaction (PCR) using species-specific primers. RESULTS In this study, 77 subjects with acute and chronic cholecystitis and control groups with a mean age of 46.85 ± 14.53 years, including 58 (67.25%) women and 19 (32.75%) men were included. DNA of 10 Helicobacter spp. was detected in the bile of the patients with cholecystitis including eight H. pylori and two H. bilis. However, we could not detect H. hepaticus and H. pullorum DNA in the samples. Moreover, there was an association between H. pylori and acute cholecystitis (p = 0.048), which was found to be stronger in 31-40-year-olds group (p = 0.003). CONCLUSION We found an association between the presence of H. pylori DNA and acute gallstone cholecystitis. There is not statistically significant correlation between three enterohepatic Helicobacter spp. ( H. bilis, H. hepaticus , and H. pullorum) and cholelithiasis. Given the low sample size of the patients, more studies are required to clear the clinical role of Helicobacter spp. in the gallstone disease and cholecystitis.

The Inhibition Effect of Lactobacilli Against Growth and Biofilm Formation of Pseudomonas aeruginosa.

The emergence of antibiotic-resistant and food-spoilage microorganisms has renewed efforts to identify safe and natural alternative agents of antibiotics such as probiotics. The aim of this study was the isolation of lactobacilli as potential probiotics from local dairy products with broad antibacterial and anti-biofilm activities against antibiotic-resistant strains of Pseudomonas aeruginosa and determination of their inhibition mechanism. Antibiotic susceptibility and classification of acquired resistance profiles of 80 P. aeruginosa strains were determined based on Centers for Disease Control and Prevention (CDC) new definition as multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan-drug-resistant (PDR) followed by antibacterial assessment of lactobacilli against them by different methods. Among the 80 P. aeruginosa strains, 1 (1.3%), 50 (62.5%), and 78 (97.5%) were PDR, XDR, and MDR, respectively, and effective antibiotics against them were fosfomycin and polymyxins. Among 57 isolated lactobacillus strains, two strains which were identified as Lactobacillus fermentum using biochemical and 16S rDNA methods showed broad inhibition/killing and anti-biofilm effects against all P. aeruginosa strains. They formed strong biofilms and had bile salts and low pH tolerance. Although investigation of inhibition mechanism of these strains showed no bacteriocin production, results obtained by high-performance liquid chromatography (HPLC) analysis indicated that their inhibitory effect was the result of production of three main organic acids including lactic acid, acetic acid, and formic acid. Considering the broad activity of these two L. fermentum strains, they can potentially be used in bio-control of drug-resistant strains of P. aeruginosa.

Resistotyping, phenotyping and genotyping of New Delhi metallo-ß-lactamase (NDM) among Gram-negative bacilli from Iranian patients.

PURPOSE: The purpose of this study was to investigate New Delhi metallo-ß-lactamase (NDM) production among Gram-negative bacilli. METHODOLOGY: Antibiogram-resistotyping and detection of New Delhi metallo-ß-lactamase (NDM) in clinical isolates of Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa and comparative evaluation of the diagnostic performance of three phenotypic methods for NDM detection, with PCR considered as the gold standard, were performed. Minimum inhibitory concentration (MIC) of antibiotics against NDM-positive strains using E-tests and clonal relationship analysis using enterobacterial repetitive intergenic consensus (ERIC)-PCR in these strains were determined. RESULTS: The most effective antibiotics against strains of the species K. pneumoniae were Colistin, Chloramphenicol and Tigecycline; against P. aeruginosa were Fosfomycin and Polymyxins, and against A. baumannii were Polymyxins, Ampicillin/Sulbactam and Minocycline. Overall, 66, 31 and 40 different resistotypes were observed among K. pneumoniae, A. baumannii and P. aeruginosa strains, respectively. The blaNDM-1 gene was detected in 28 (8.5 %) strains of the bacteria investigated. The sensitivities and specificities of the Meropenem-EDTA combined disk test, the meropenem-dipicolinic acid combined disk test and the modified Hodge test methods for NDM detection were 96.43, 55.15; 96.43, 54.85; and 89.29, 35.15, respectively. Additionally, in spite of the low positive predictive values of these tests, their negative predictive values were high. ERIC-PCR results revealed two main clusters in NDM-positive strains of each of the species P. aeruginosa and A. baumannii, and ten main clusters in K. pneumoniae. In all the NDM-positive strains maximum MIC rates (>256) were observed for all beta-lactam antibiotics. CONCLUSION: There were high levels of antibiotic resistance and a high frequency of multi-drug resistance and extensive-drug resistance profiles, as well as highly prevalent blaNDM-1 genes in the bacteria investigated.

Determination of Acquired Resistance Profiles of Pseudomonas aeruginosa Isolates and Characterization of an Effective Bacteriocin-Like Inhibitory Substance (BLIS) Against These Isolates.

BACKGROUND: The emergence of pan-drug resistant strains (PDR) of Pseudomonas aeruginosa has led to renewed efforts to identify alternative agents, such as bacteriocins and bacteriocin-like inhibitory substances (BLISs). OBJECTIVES: The aims of this study were to determine the acquired resistance profiles of multidrug-resistant (MDR), extensively drug-resistant (XDR), and PDR P. aeruginosa isolates based on the revised definitions of the CDC and ECDC and to screen and characterize effective BLISs against these isolates. PATIENTS AND MATERIALS: In a cross-sectional study, 96 P. aeruginosa strains were isolated during a 12-month period. The resistance profiles of these isolates were determined as MDR, XDR, and PDR, and the data were analyzed using WHONET5.6 software. A BLIS against the P. aeruginosa strains was characterized based on its physicochemical properties, size, growth curves, and production profiles. RESULTS: Among the 96 isolates of P. aeruginosa, 2 (2.1%), 94 (97.9%), and 63 (65.6%) were non-MDR, MDR, and XDR, respectively, and 1 (1.1%) was PDR. The most effective antibiotics against these isolates were polymyxins and fosfomycin. A BLIS isolated from the P. aeruginosa DSH22 strain had potent activity against 92 (95.8%) of the 96 isolates. The BLIS was heat stable, (up to 100°C for 10 min), UV stable, and active within a pH range of 3 - 9. The activity of BLIS disappeared when treated with trypsin, proteinase K, and pepsin, indicating its proteinous nature. Based on its size (25 kDa), the BLIS may belong to the large colicin-like bacteriocin family. BLIS production started in the midexponential phase of growth, and the maximum level (2700 AU/mL) occurred in the late-stationary phase after 25 hours of incubation at 30°C. CONCLUSIONS: This BLIS with broad-spectrum activity may be a potential agent for the treatment or control of drug-resistant strains of P. aeruginosa infection.

Frequency assessment of ß-lactamase enzymes in Escherichia coli and Klebsiella isolates in patients with urinary tract infection.

BACKGROUND: Production of ß-lactamase enzymes is the most common and important mechanism of resistance in Gram-negative bacteria. The objective of this study was to assess frequency of three main ß-lactamase enzymes, including extended spectrum ß-lactamases (ESBLs), metallo-ß-lactamase (MBL), and Klebsiella pneumoniae carbapenemase (KPC) enzymes in Escherichia coli and Klebsiella spp. isolated from nosocomial and community urinary tract infections (UTI). MATERIALS AND METHODS: In a cross-sectional study from March to December 2012, midstream urine samples were obtained from patients suspicious of UTI who were hospitalized or referred to Al-Zahra Hospital, Isfahan, Iran. Samples were cultured and E. coli and Klebsiella spp. were isolated. Prevalence of ESBLs, KPC, and MBLs producing E. coli and Klebsiella spp. were studied by double-disk (combined-disk), the modified Hodge test and imipenem-ethylenediaminetetraacetic acid combined disc methods respectively. In addition, their antimicrobial susceptibility patterns determined and resistant to carbapenem drugs confirmed by minimum inhibitory concentrations based on E-test method. RESULTS: A total of 1080 E. coli and 484 Klebsiella strains were isolated during study period. Among 720 E. coli and 384 Klebsiella isolates from hospitalized patients, 300 (41.7%) and 198 (51.5%) were ESBLs producers, respectively. In out-patients samples, the rate of ESBLs production was 25% (90/360) and 40% (40/100) in E. coli and Klebsiella isolates, respectively. Prevalence of MBLs producing in hospital E. coli and Klebsiella isolates were 0.3% (2/720) and 2.6% (10/384), and for KPC data were 1.4% (10/720) and 48.4% (186/384), respectively. No MBLs and KPC producing isolate was seen in non-hospital E. coli and Klebsiella isolates except for one non-hospital KPC producing Klebsiella isolate. CONCLUSION: The result of our study showed high prevalence of ESBLs and KPC, but low prevalence of MBLs in cultured bacteria from urine samples of patients with acute UTI. In addition, KPC was the main carbapenem resistance mechanism in Klebsiella and E. coli isolates.