Antibacterial effect of cerium oxide nanoparticle against Pseudomonas aeruginosa.

BACKGROUND: Antibiotics have been widely used for the treatment of bacterial infections for decades. However, the rapid emergence of antibiotic-resistant bacteria has created many problems with a heavy burden for the medical community. Therefore, the use of nanoparticles as an alternative for antibacterial activity has been explored. In this context, metal nanoparticles have demonstrated broad-spectrum antimicrobial activity. This study investigated the antimicrobial activity of naked cerium oxide nanoparticles dispersed in aqueous solution (CNPs) and surface-stabilized using Pseudomonas aeruginosa as a bacterial model. METHODS: Gelatin-polycaprolactone nanofibers containing CNPs (Scaffold@CNPs) were synthesized, and their effect on P. aeruginosa was investigated. The minimum inhibitory and bactericidal concentrations of the nanoparticls were determined in an ATCC reference strain and a clinical isolate strain. To determine whether the exposure to the nanocomposites might change the expression of antibiotic resistance, the expression of the genes shv, kpc, and imp was also investigated. Moreover, the cytotoxicity of the CNPs was assessed on fibroblast using flow cytometry. RESULTS: Minimum bactericidal concentrations for the ATCC and the clinical isolate of 50 µg/mL and 200 µg/mL were measured, respectively, when the CNPs were used. In the case of the Scaffold@CNPs, the bactericidal effect was 50 µg/mL and 100 µg/mL for the ATCC and clinical isolate, respectively. Interestingly, the exposure to the Scaffold@CNPs significantly decreased the expression of the genes shv, kpc, and imp. CONCLUSIONS: A concentration of CNPs and scaffold@CNPs higher than 50 µg/mL can be used to inhibit the growth of P. aeruginosa. The fact that the scaffold@CNPs significantly reduced the expression of resistance genes, it has the potential to be used for medical applications such as wound dressings.

Bacterial biofilm in colorectal cancer: What is the real mechanism of action?

Human colorectal cancer is the third most common cancer around the world. Colorectal cancer has various risk factors, but current works have bolded a significant activity for the microbiota of the human colon in the development of this disease. Bacterial biofilm has been mediated to non-malignant pathologies like inflammatory bowel disease but has not been fully documented in the setting of colorectal cancer. The investigation has currently found that bacterial biofilm is mediated to colon cancer in the human and linked to the location of human cancer, with almost all right-sided adenomas of colon cancers possessing bacterial biofilm, whilst left-sided cancer is rarely biofilm positive. The profound comprehension of the changes in colorectal cancer can provide interesting novel concepts for anticancer treatments. In this review, we will summarize and examine the new knowledge about the links between colorectal cancer and bacterial biofilm.

Brucella melitensis VirB12 recombinant protein is a potential marker for serodiagnosis of human brucellosis.

BACKGROUND: The numerous drawbacks of current serological tests for diagnosis of brucellosis which mainly results from cross reactivity with LPS from other gram-negative bacteria have generated an increasing interest to find more specific non-LPS antigens. Previous studies had indicated that Brucella VirB12 protein, a cell surface protein and component of type IV secretion system, induces antibody response during animal infection. However, this protein has not yet been tested as a serological diagnostic marker in human brucellosis. METHODS: Recombinant VirB12 protein was prepared and evaluated the efficacy of it in an indirect enzyme-linked immunosorbent assay (ELISA) for brucellosis with sera collected from different region of Iran and the results were compared with a commercial ELISA kit. RESULTS: Sera from human brucellosis patients strongly reacted to the purified recombinant VirB12. The sensitivity, specificity, accuracy, negative predictive value and positive predictive value of recombinant VirB12-based ELISA related to the commercial-ELISA method were 87.8, 94, 90, 80 and 96.6% respectively. CONCLUSIONS: We concluded that antigenic VirB12 have a property value that can be considered as a candidate for using in serodiagnostic tests for human brucellosis.

[Serotype distribution and antimicrobial resistance rates of Shigella spp. isolates in Tehran, Iran]. / Tahran'da izole edilen Shigella türlerinin serotip dagilimi ve antimikrobiyal direnç oranlari.

In this study, antimicrobial resistance patterns and serotype distributions of Shigella spp. isolated from pediatric and adult patients with diarrhea, inhabiting in Tehran, were investigated. Stool specimens of 1350 patients with diarrhea who were admitted to the seven different hospitals in Tehran from November 2003 till March 2005 were taken into the study. Antibacterial susceptibility patterns of Shigella spp. isolates were determined by standard disk diffusion method. Overall isolation rate of Shigella spp. was found as 11.5 percent. S. sonnei was the most frequent species (55.1%) followed by S. flexneri (30.8%), S. boydii (9.6%) and S. dysenteria (4.5%). Resistance rates to ampicillin (81.4%), trimethoprim-sulphamethoxazole (93.6%), chloramphenicol (28.2%) and tetracycline (98.7%) were high, whereas low resistance rates to cefixime (5.1%) and nalidixic acid (2.6%) were detected. All isolates were found susceptible to ceftriaxone and ciprofloxacine. These data may help physicians for choosing appropriate empirical chemotherapy although subsequent antibacterial susceptibility testing is always recommended.

An evaluation study on phenotypical methods and real-time PCR for detection of Mycobacterium tuberculosis in sputa of two health centers in Iran.

BACKGROUND AND OBJECTIVES: For further confirmation of the previous in-house real-time PCR and CYP 141 target as a rapid and cheap diagnostic technique and a new target for direct detection of Mycobacterium tuberculosis, we evaluated and compared the results of smear, culture and real-time PCR in sputa that were collected from 2 health centers. Moreover we tried to evaluate the diagnostic accuracy of phenotypical methods for detection of tuberculosis that have been applied in two health centers of Iran. MATERIALS AND METHODS: Thirty two sputa (including 15 smear positive and 17 smear negative) and 53 Sputa (29 smear and culture positive and 24 smear and culture negative specimens) were collected from tuberculosis suspected patients from health center No. 1 and 2 respectively. A Taqman probe was used for direct detection of M. tuberculosis using the specific primers. RESULTS: Because of the results, data of health center No. 1 was not reliable. The average number of bacteria that was detected in health center No. 2 by real time PCR was 1.2E+003-7.3+004; 1.4E+004-1.29+005 and 8.27E+005-1.07+006 for one to three plus smear result groups, respectively. The overall sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of real-time PCR were 96.5% (28/29), 95.8% (23/24), (96.6%) and (96%), respectively. CONCLUSION: Compared with the results of previous studies and being a good correlation between real-time PCR and phenotypic methods, emphasize that CYP141 is a good target for quantification of M. tuberculosis in sputa and real-time PCR can be a good method for evaluation of smear microscopy. Moreover, further surveillance is needed to evaluate the phenotypical methods and final decisions that are taken in health centers of Iran that can be observed and evaluated by the cheap molecular methods like in-house methods.

Species-specific PCR for the Diagnosis and Determination of Antibiotic Susceptibilities of Brucella Strains Isolated from Tehran, Iran.

BACKGROUND: Brucellosis is an endemic zoonotic disease in the Middle East. This study intended to design a uniplex PCR assay for the detection and differentiation of Brucella at the species level and determining the antibiotic susceptibility pattern of Brucella in Iran. METHODS: Sixty-eight Brucella specimens (38 animal and 30 human specimens) were analyzed using PCR (using one pair of primers). Antibiotic susceptibility patterns were evaluated and compared using the E-Test and disk diffusion susceptibility test. Tigecycline susceptibility pattern was compared with other antibiotics. RESULTS: Thirty six isolates of B. melitensis, 2 isolates of B. abortus and 1 isolate of B. suis from the 38 animal specimens, 24 isolates of B. melitensis and 6 isolates of B. abortus from the 30 human specimens were differentiated. The MIC50 values of doxycycline for human and animal specimens were 125 and 10 µg/ml, respectively, tigecycline 0.064 µg/ml for human specimens and 0.125µg/ml for animal specimens, and trimethoprim/ sulfamethoxazole and ciprofloxacin 0.065 and 0.125µg/ml, respectively, for both human and animal specimens. The highest MIC50 value of streptomycin in the human specimens was 0.5µg/ml and 1µg/ml for the animal specimens. The greatest resistance shown was to tetracycline and gentamicin, respectively. CONCLUSION: Uniplex PCR for the detection and differentiation of Brucella at the strain level is faster and less expensive than multiplex PCR, and the antibiotics doxycycline, rifampin, trimethoprim-sulfamethoxazole, ciprofloxacin, and ofloxacin are the most effective antibiotics for treating brucellosis. Resistance to tigecycline is increasing, and we recommend that it be used in a combination regimen.

Evaluation of human papillomavirus infections in prostatic disease: a cross-sectional study in Iran.

BACKGROUND: The role of inflammation in prostate diseases is suggested by the presence of inflammatory cells within the prostate in benign prostatic hyperplasia (BPH) and prostate cancer (PCa) patients. In addition, bacterial and viral infection may lead to chronic and recurrent inflammation of the prostate. The human papillomaviruses (HPVs) are a family of sexually transmitted viruses which have been implicated in the aetiology of cervical cancer and several other malignancies. This study evaluated the frequency of HPV infection in individuals with prostatic disease in Iran. MATERIALS AND METHODS: The study included formalin fixed paraffin- embedded tissue samples of 196 primary prostate cases, including 29 PCa and 167 BPH samples. HPV DNA was purified and amplified through MY09/MY11 and GP5+/GP6+ primers with nested PCR. All patients were interviewed using a questionnaire to collect demographic information. RESULTS: Nested PCR showed that HPV DNA was found in 17.2 percent of PCa samples and 4.8 percent of BPH samples (not significant). CONCLUSIONS: Our data do not support a significant role of HPV infection in prostatic disease in Iranian patients, but demographic data indicated a probable association between presence of HPV DNA and risk of inflammation in prostate tissue which might lead to prostate carcinoma. Further studies are required to elucidate any roles of HPV infection in prostatic disease.

Peptide-based Polyclonal Antibody Production against P110 Protein of Mycoplasma genitalium.

Mycoplasma genitalium (M.genitalium) is a sexually transmitted pathogen. Detection of this microorganism in clinical specimens by culture is rather difficult and time consuming. The aim of this study was to produce polyclonal antibody against a synthetic peptide from P110 protein of M.genitalium in order to develop a diagnostic tool for detection of this microorganism in clinical specimens. A synthetic peptide from P110 protein was conjugated to Keyhole Limpet Hemocyanin (KLH) and used for immunization of a white New Zealand rabbit. The produced antibody was purified by affinity chromatography and its specific interaction with immunizing peptide was determined by ELISA. Immunoreactivity of the antibody was also tested by Western blotting in bacterial cell lysate prepared from M.genitalium G-37. To confirm its application as a diagnostic tool, indirect immunofluorescent staining method was performed on M.genitalium-infected PBMC using anti-P110 as the primary antibody. The results showed that produced antibody has excellent reactivity with immunizing peptide and also detected a single band of 110 kDa corresponding to P110 protein. M.genitalium-infected PBMC showed a bright fluorescent signal in IF staining. This antibody might be used as a tool in diagnostic applications.

Prospective evaluation of a new "paper urease test" for ultra-rapid detection of Helicobacter pylori.

BACKGROUND: The purpose of this study was to determine the sensitivity, specificity, and positive and negative predictive values of a newly developed paper urease test (PUT) for ultra-rapid detection of helicobacter pylori (HP) in gastric mucosa. MATERIAL/METHODS: 100 patients (43 men) with a mean age of 57+/-6.8 years participated. Patients presenting for upper endoscopy with no recent exposure to HP-altering drugs were enrolled. Gastric biopsy specimens were tested by the PUT and histology methods, and then the patients underwent [13C] urea breath tests (UBT). HP was considered positive when either UBT or histology demonstrated it, and negative if HP was not detected in either UBT or histology. The PUT was reported at 15 minutes. RESULTS: 87 of 100 patients tested positive for HP. The PUT correctly identified 74 of 87 HP-positive and 13 of 13 HP-negative patients, yielding sensitivity, specificity, and positive and negative predictive values of 87%, 100%, 100% and 53.5%, respectively, in this population. CONCLUSIONS: Rapidly available and reliable results from the PUT can facilitate clinical decision prior to patient discharge from the endoscopy suite. We recommend PUT for screening of HP in endoscopy candidates, due to high specificity, rapid reaction, simplicity and low cost. A positive result shows a definite diagnosis, although a negative result needs further diagnostic methods.