Synthesis of ZIF-8/ZnFe2O4/GO-OSO3H nanocomposite as a superior and reusable heterogeneous catalyst for the preparation of pyrimidine derivatives and investigation of their antimicrobial activities.

In this report, we synthesized some pyrimidine derivatives by multi-component reaction of urea, benzaldehydes, and 1,3-indandione in the presence of ZIF-8/ZnFe2O4/GO-OSO3H nanocomposite under reflux conditions. Initially, graphene oxide was prepared from graphite, and then it was sulfonated using ClOSO3H. Next, GO-OSO3H nanosheets were used to support ZIF-8/ZnFe2O4 nanostructure. The construction of the synthesized structure was established using different spectral techniques such as X-ray crystallography (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX/Mapping), Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM), and Brunauer-Emmett-Teller (BET). The present method provides various benefits including the efficiency of outcomes, easy separation of the catalyst, and excellent yield of the products within short reaction times. Moreover, the antibacterial activities of pyrimidine derivatives were investigated via the agar-well diffusion method on gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria and the obtained results illustrated reasonable effects.

Evaluation of anti-biofilm potential of biosurfactant extracted from Nocardia species.

INTRODUCTION: Bacterial natural products such as biosurfactants and surface-active agents are important compounds which exhibit many applications in the fields of medicine. AIM: The aim of the present study was to isolate and identify Nocardia strains with high biosurfactant production and antibiofilm ability. MATERIALS AND METHODS: In the present study, a biosurfactant producing Nocardia species was isolated and identified by a laboratory method. Nocardia species were initially screened and then tested for their ability to produce biosurfactant. The oil spreading test and the surface tension measurements showed that one strain was a biosurfactant producer. The strain with the best surface activity results was selected for further studies and identified by 16S rRNA gene sequencing method. Fourier transform infrared spectroscopy (FTIR) and compositional analysis proved a biosurfactant structure. RESULTS: Oil spreading test and blue agar plate test confirmed biosurfactants and extracellular anionic glycolipids. E24% assay using olive oil revealed strong emulsifying characteristic of the extracted biosurfactant with 100% emulsifying strength. FTIR spectrum indicated the presence of aliphatic hydrocarbon chain (lipid) along with the polysaccharide portion, confirming the glycolipid nature of the biosurfactant. The stability of the biosurfactant produced in different conditions was significant. Increasing concentration of BS significantly inhibited Pseudomonas aeruginosa biofilm. CONCLUSIONS: N. coubleae can be a representative of the genus Nocardia for the production of biosurfactants with beneficial physicochemical properties.

Association between Presence of RmpA, MrkA and MrkD Genes and Antibiotic Resistance in Clinical Klebsiella pneumoniae Isolates from Hospitals in Tehran, Iran.

BACKGROUND: Klebsiella pneumoniae is an opportunistic pathogen causing nosocomial infection in human. This study aimed to investigate the relationship between the presence of genes involved in biofilm formation in K. pneumoniae isolated from patients and the presence of antibiotic resistance genes. METHODS: Biochemical tests were used for the identification of K. pneumonia isolated from urine samples referred to hospitals in Tehran, Iran, from Sep 2018 to Jan 2020. The antibiotic resistance pattern was performed and biofilm formation was assessed phenotypically. Finally, ß-lactamase genes and adhesion genes were detected by the PCR method. RESULTS: We collected 457 K. pneumoniae isolates from hospitals in Tehran, Iran. 110 isolates were resistant to imipenem. Fifty isolates were positive for metallo-ß-lactamases that thirty-nine isolates (35.45%) has blaKPC gene, 18 isolates (16.36%) had blaVIM-1 gene and 9 isolates (8.18%) had blaIMP-1 gene detected by PCR. Sixty isolates (54.54%) had strong biofilm, 35 isolates (31.81%) had moderate biofilm and 15 isolates (13.63%) had weak biofilm. The presence of adhesion genes in K. pneumoniae isolates significantly correlated with resistance genes (P<0.001). CONCLUSION: It is clear antibacterial resistance has been significant association with biofilm formation in K. pneumoniae isolates. Therefore, understanding resistance pattern and mechanisms leading to biofilm formation can facilitate efficient treatment of infections caused by K. pneumoniae.

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.

Antibacterial Activity of Gold Nanoparticles Conjugated by Aminoglycosides Against A. baumannii Isolates from Burn Patients.

BACKGROUND AND OBJECTIVE: Today, resistance to multiple classes of antibiotics, and notably to the ß-lactam and aminoglycosides in A. baumannii is becoming a great problem and it necessitates to make a new approach to combat with multidrug-resistant (MDR), extensive drug-resistance (XDR) or Pandrug-resistant (PDR) isolates. In this case, a new strategy and ways should be designed and introduced against such infections. Therefore the aim of the present study was the evaluation of antibacterial activity of nanoconjugate gentamicin and amikacin with gold against clinical isolates of A. baumannii that were collected from burn wound infection. There are some patents of gold nanoparticles that are conjugated with antibiotics (WO2017161296A1, US20090181101A1). METHODS: Eighteen A. baumannii were collected from burn wound infections. For confirmation and detection of aminoglycoside-resistant genes, PCR was carried out. Gold nanoparticles and nanoconjugates were prepared according to the protocol. For the evaluation of the nanoconjugate, Dynamic light cattering, Transmission electron microscopy and FTIR Analysis were carried out. Then, the antibacterial activity of nanoconjugates was conducted by using micro broth dilution method. RESULT: Prevalence of aminoglycoside-resistant genes was aacC1, aphA6, aadA1, aadB genes 55.5%, 22.2%, 38.8% and 22.2% respectively. Synthesis of bare nanoconjugates resulted in nanoparticle in a size of 10 nm. Amikacin bound to Gnps showed excellent antibacterial activity (94.5%) and just one isolate showed intermediate resistance. Also, gentamicin bound to Gnps had a good antimicrobial effect (50%) in contrast to gentamicin alone. CONCLUSION: Our study showed that a combination of amikacin and gentamicin with Gnps has a significant antibacterial efficiency against clinical isolates of A. baumannii. Gnps can be used as extraordinary molecular carriers for targeting, and delivery of the antibiotic molecules to the specific infection.

Detection of VIM-1 and IMP-1 genes in Klebsiella pneumoniae and relationship with biofilm formation.

Klebsiella pneumoniae is an important human pathogen that is considered in recent years due to nosocomial infections resistant to treatment as well as the ability to form biofilms particularly in patients with urinary tract infection in ICU or hospital. The aim of this study was to evaluate the prevalence of VIM1, IMP1 genes and their ability to form biofilm in K. pneumoniae strains isolated from patients with urinary tract infection. In the study, using culture and biochemical methods, 1807 K. pneumoniae samples were isolated from patients with urinary tract infection hospitalized or referred to hospitals in Qom in 2013-2014. For isolation of MBL producing isolates, Double Disk Synergy Test (DDST) was used. Then MBL positive isolates were examined for the presence of VIM1, IMP1 genes using PCR method. Furthermore, all strains were investigated for biofilm formation by phenotypic microplate method. From 3165 urine samples cultured, 1807 isolates of K. pneumoniae were isolated and 109 strains (93.2%) were positive for MBL enzymes production. PCR results showed that the prevalence of VIM1 and IMP1 genes are 15.6 and 6.4%, respectively. The Phenotypic method indicated that 91.2% of isolates formed biofilm. Biofilm formation in K. pneumoniae isolates is high and there is a significant relationship between strong biofilm formation and prevalence of VIM1 and IMP1 genes. Also due to the presence of MBL genes in K. pneumoniae and horizontal transfer of genes to other bacteria, and to control the indiscriminate use of antibiotics, the hospital infection control methods must be considered.

Sleep quality and insomnia in nurses with different circadian chronotypes: morningness and eveningness orientation.

BACKGROUND: Morningness and eveningness preference (chronotype), an endogenous component of the circadian clock could play a key role in a worker's ability for adjusting to shift work. Morning types are those individuals who prefer going to bed and waking up early, whereas Evening types tend to sleep at later hours and find it difficult to get up in the morning. OBJECTIVE: The objective of this study was to survey, the relationship between morningness-eveningness type, sleep quality and insomnia in shift worker nurses. PARTICIPANTS: The participants comprised 160 nurses working in three different wards in two university hospitals in Iran. METHODS: Nurses completed the Horne and Ostberg questionnaire to assess the distribution of morningness or eveningness preference, the Pittsburg Sleep Quality Index and Insomnia Severity Index questionnaire to measure self reported sleep quality and insomnia. Demographic information was also collected in order to explore the relationship between circadian rhythms, sleep quality and prevalence of insomnia in shift workers. RESULTS: The results showed that the prevalence of poor sleep quality was high. More than half of the participants had poor sleep. Evening type nurses had worse sleep quality in our study (P < 0.05). There is not any significant association between the shift type and age of the nurses with their quality of sleep (P > 0.05). CONCLUSIONS: The results suggested that nurses who had a morning sleep preference had better sleep quality. A survey of chronotype of nurses could be useful, so that individuals may be assigned to different shifts according to their sleep preference.