Construction of metronidazole capped in gold nanoparticles against Helicobacter pylori: antimicrobial activity improvement.

INTRODUCTION: Helicobacter pylori is considered a major agent causing gastritis and peptic ulcer disease. Unfortunately, the occurrence of increasing drug resistance to this bacterium would result in some difficulties in its treatment. Therefore, the application of nanotechnology has been suggested to resolve such problems. Nanoparticles usage in medical research has been expanded in recent years. Among nanometals, gold nanoparticles have exclusive features that can be used in such applications. Using nanotechnology in medical science could help mankind to solve this problem in the future. AIM: Our aim in this research was to investigate the antimicrobial effect of gold nanoparticles on H. pylori strains. MATERIALS AND METHODS: Gold nanoparticles were synthesized by the Turkevich method. Then, their size and dispersion were investigated using spectrophotometry, DLS, and TEM microscopy. Subsequently, the combination of metronidazole and gold nanoparticles was obtained by mixing method, and then the anti-helicobacter effects of the two were evaluated according to CLSI. RESULTS: The highest size of gold nanoparticles was between 12 and 9 nm, and the maximum absorbance was 522 nm; however, in conjugated state, the maximum absorbance was 540 nm, which indicated the accumulation of drug-conjugated nanoparticles in the conjugate state. Some changes indicated the binding of metronidazole to gold nanoparticles. Antimicrobial testing of gold nanoparticles and metronidazole did not affect the Helicobacter pylori. Therefore, the combination of gold nanoparticles and metronidazole had a 17-mm growth inhibition zone. CONCLUSIONS: The anti-helicobacter effects of metronidazole significantly increased in conjugation with gold nanoparticles.

Prevalence and molecular characterization of non-tuberculous mycobacteria in hospital soil and dust of a developing country, Iran.

The presence and diversity of mycobacteria that are capable of survival in a harsh and adverse condition, such as hospital environments, have not been comprehensively studied. This study aimed to assess the frequency and diversity of mycobacteria in hospital soil and dust of a developing country using a combination of molecular and conventional methods. A total of 318 hospital dust and soil samples collected from 38 hospitals were analysed using standard protocols for characterization of mycobacteria. The conventional tests were used for preliminary identification and Runyon's classification, the PCR amplification of the hsp65 gene and sequence analyses of 16SrRNA were applied for genus and species identification. In total, 28 samples (8.8 %) were positive for mycobacteria. The isolates included 33 mycobacteria species including 19 rapidly growing and 14 slowly growing organisms. The most prevalent species were M. setense and M. lentiflavum, five isolates (15.1 %) each, M. fortuitum, four isolates (12.12 %) and M. kumamotonense and M. massiliense/abscessus complex three isolates (9.1 %) each, M. arupense and M. frederiksbergense, two isolates (6 %) each. The remaining isolates consisted the single strains of eight various mycobacterium species, the results of our study revealed that soil and dust in hospitals can be the reservoir of mycobacteria. This reaffirms the fact that these organisms due to intrinsic resistance can persist in hospitals and create a threat to patient's health, in particular to those who suffer from weakness of immunity.

Species diversity and molecular characterization of nontuberculous mycobacteria in hospital water system of a developing country, Iran.

BACKGROUND: Hospital environment is of crucial importance in cross-transmission of opportunistic pathogens to the patients. Nontuberculous mycobacteria have the remarkable capability to withstand the adverse condition of hospital environments and pose a potential threat to the health of patients. The current study aimed to assess the frequency and diversity of mycobacteria in hospital water of a developing country using a combination of conventional and molecular methods. METHODS: A total of 148 hospital water samples collected from 38 hospitals were analyzed for the presence of mycobacteria using standard protocols for isolation and characterization of the isolates. The conventional tests were used for preliminary identification and Runyon's classification, the PCR amplification of hsp65 gene and sequence analysis of 16S rRNA were applied for the genus and species identification. RESULTS: A total of 71 [48%] isolates including 30 rapidly growing and 41 slowly growing mycobacteria were recovered. The three most prevalent species were M. lentiflavum, 28.2%, M. paragordonae, 21.1%, and M. fredriksbergense, 9.8%, followed by M. simiae and M. novocastrense, 7%, M. canariasense and M. cookii like, 5.6%, M. setense, 4.2%, M. fortuitum and M. gordonae, 2.8%, and the single isolates of M. austroafricanum, M. massiliense, M. obuense, and M. phocaicum like. CONCLUSION: The results of our study show that the hospital water resources, drinking or non-drinking can be the reservoir of a diverse range of mycobacteria. This reaffirms the fact that these organisms due to intrinsic resistance to common antiseptic and disinfectant solutions persist in hospitals and create a threat to the patient's health and in particular to those that suffer from weakness of immunity.