Antibacterial Activities of 5-Nitro-2-uryl and 5-Nitro-2-Imidazolyl Derivatives of 1,3,4-Thiadiazole

Introduction: Nitrofurans and nitroimidazoles are broad-spectrum antimicrobial agents, which affect the microbial DNA. The aim of the present study was to evaluate the new derivatives of these two groups of antimicrobials against certain Gram-positive and Gram-negative bacterial strains. Materials and Methods: Seven new derivatives of nitrofurans and nitroimidazoles were synthesized, and 6.4 mg of each derivative was dissolved in dimethyl sulfoxide. Then, 8 serial dilutions (0.5, 1, 2, 4, 8, 16, 32, and 64 μg/ml) of each derivative was prepared using Muller-Hinton broth, and the minimum inhibitory concentration for each derivative was measured and compared to ciprofloxacin (standard). Results: All the derivatives had no antibacterial effects against Gram-negative bacteria (minimum inhibitory concentration > 64 μg/ml); only 2-(5-nitro-2-furyl)-5-(n-pentylsulfunyl)-1,3,4-thiadiazole exhibited mild antibacterial effects against Klebsiella pneumonia (minimum inhibitory concentration of 16-32 μg/ml). The antibacterial effects of the derivatives against Gram-positive bacteria also showed variations from complete inhibition of the growth of Staphylococcus epidermidis and Bacillus subtilis (minimum inhibitory concentration < 0.5 μg/ml) by 2-(5-nitro-2-furyl)-5-(n-buthylthio)-1,3,4-thiadiazole to no inhibition of S. epidermidis and streptococcus pyogenes. Conclusion: These compounds have weak antibacterial effects; only two derivatives showed antibacterial effects similar to that of the positive control

Comparison of myocardial perfusion between the users of two antiepileptic medications: valproate vs. carbamazepine

Objective(s): The prevalence of coronary artery disease (CAD) is high in patients with epilepsy using antiepileptic drugs (AED). Epilepsy, AED, or the type and duration of AED use , may contribute to higher CAD risk.In this study, myocardial perfusion imaging (MPI) was compared between patients using carbamazepine and valproate.Method: Out of 73 patients receiving carbamazepine or valproate monotherapy for more than 2 years, visited at a tertiary referral clinic, 32 patients participated in a 2-day stress and rest phases MPI. For each phase, 15-25 mCi 99mTc-MIBI was injected, at peak exercise or by pharmacologic stimulation for the stress phase. SPECT with cardiac gating was done by a dual-head gamma camera and processed and quantified. Scans with at least one definite reversible hypo-perfusion segment were considered abnormal.Results: Seventeen patients received carbamazepine monotherapy and 15 valproates. Age and duration of AED use were similar between the groups. Two scans were abnormal (6.3%) both in valproate group (13.3%). Duration of AED use was higher in patients with abnormal scans. In patients receiving monotherapy >2 years, the frequency of abnormal MPI was similar between groups (P-value=0.12).  In patients receiving monotherapy > 5 years, prevalence of abnormal MPI was higher in the valproate group (28.6% vs. 0.0%; P-value=0.042). Considering valproate subgroup, ischemic patients had higher duration of AED use, comparing with the normal patients (17.0±4.2 vs. 6.4±4.8, P-value=0.014).Conclusion: MPIs were abnormal in patients receiving valproate after 5 years compared to patients receiving carbamazepine. Long-term valproate use may increase the risk of CAD

Detection of Extended-Spectrum beta-Lactamases among Acinetobacter Baumannii Isolated from Hospitals of Qazvin, Iran

BACKGROUND፡ Acinetobacter baumannii is a major contributor to nosocomial infections. Extended-spectrum ßlactamase (ESBL)-producing A. baumannii is spreading worldwide. We aimed to determine the frequency of ESBLencoding genes in clinical isolates of A. baumannii and to access their clonal relationship by repetitive extragenic palindromicPCR (rep-PCR). METHODS: In this descriptive cross-sectional study, 203 isolates of A. baumannii were collected from Qazvin hospitals. The Identification of isolates was performed by standard laboratory methods. To verify ESBL production, all isolates were screened by disk agar diffusion and confirmed by the combined disk method. Subsequently, ESBL-encoding genes were detected by PCR and sequencing. Possible clonal association of ESBL-producing isolates was evaluated using rep-PCR. RESULTS: Two hundred (98.5%) isolates showed reduced susceptibility to one of the antibiotics used in the ESBL screening test, of which 127 isolates (62.6%) produced ESBL. PCR results showed blaOXA-1 (20.5%) was the most prevalent gene followed by blaTEM-1 (20%), blaGES-1 (15.7%), blaCTX-M-15 (7.9%), and blaPER-1 (1.6%). Rep-PCR results revealed that ESBL-producing isolates belonged to clones A (85%), B (13.4%), and C (1.6%). CONCLUSION: Our study showed the significant presence of blaOXA-1, blaTEM-1, blaGES-1, blaCTX-M-15, and blaPER-1 genes in ESBLproducing A. baumannii isolates in the studied hospitals. This is the first report on the emergence of blaOXA-1 gene in these isolates in Iran. The use of comprehensive antimicrobial treatment guidelines based on laboratory data and appropriate infection control interventions are essential

High level of resistance to metronidazole and clarithromycin among Helicobacter pylori clinical isolates in Qazvin province, Iran

The treatment of patients with Helicobacter pylori infection has many limitations, especially because of antibiotic resistance. We aimed to investigate the prevalence and mechanism of antibiotic resistance to metronidazole and clarithromycin in H. pylori isolates collected from patients with gastrointestinal symptoms in Qazvin, Iran. In this cross-sectional study, antibiotic susceptibility testing to clarithromycin and metronidazole was performed among 80 clinical strains isolated from H. pylori-positive dyspeptic patients referred to Qazvin hospital from July 2018 to November 2018. Polymerase chain reaction (PCR) and sequencing tests were performed to determine the type of mutations in the rdxA gene in metronidazole-resistant isolates, and the 23SrRNA gene in clarithromycinresistant isolates. Thirteen (40.6%) and Twenty-one (65.6%) isolates were resistant to clarithromycin and metronidazole, respectively. 37.5% and 59.4% of clarithromycin and metronidazole resistant isolates had MIC>256. In clarithromycin-resistant isolates, mutations in the 23SrRNA gene was seen at A2143G (15.6%), A2142G (9.4%), C2195T (6.3%), C2244T (3.1%), and G2212A (3.1%) locations. In one isolate, three simultaneous mutations were recorded in locations A2143G, G2110A, and C2121T. Mutations in the rdxA gene in metronidazole-resistant isolates, were missense. High resistance to metronidazole and clarithromycin antibiotics were seen in H. pylori isolates in Qazvin province. This is the frst report of new mutation sites G2212A, G2110A, and C2121T on the 23SrRNA gene in clarithromycin-resistant isolates. It is necessary to evaluate the current situation in terms of resistance and identify the mechanisms involved in its occurrence for the successful treatment of infections caused by this organism

High level of resistance to metronidazole and clarithromycin among Helicobacter pylori clinical isolates in Qazvin province, Iran

resistance. We aimed to investigate the prevalence and mechanism of antibiotic resistance to metronidazole and clarithromycin in H. pylori isolates collected from patients with gastrointestinal symptoms in Qazvin, Iran. In this cross-sectional study, antibiotic susceptibility testing to clarithromycin and metronidazole was performed among 80 clinical strains isolated from H. pylori-positive dyspeptic patients referred to Qazvin hospital from July 2018 to November 2018. Polymerase chain reaction (PCR) and sequencing tests were performed to determine the type of mutations in the rdxA gene in metronidazole-resistant isolates, and the 23SrRNA gene in clarithromycinresistant isolates. Thirteen (40.6%) and Twenty-one (65.6%) isolates were resistant to clarithromycin and metronidazole, respectively. 37.5% and 59.4% of clarithromycin and metronidazole resistant isolates had MIC>256. In clarithromycin-resistant isolates, mutations in the 23SrRNA gene was seen at A2143G (15.6%), A2142G (9.4%), C2195T (6.3%), C2244T (3.1%), and G2212A (3.1%) locations. In one isolate, three simultaneous mutations were recorded in locations A2143G, G2110A, and C2121T. Mutations in the rdxA gene in metronidazole-resistant isolates, were missense. High resistance to metronidazole and clarithromycin antibiotics were seen in H. pylori isolates in Qazvin province. This is the first report of new mutation sites G2212A, G2110A, and C2121T on the 23SrRNA gene in clarithromycin-resistant isolates. It is necessary to evaluate the current situation in terms of resistance and identify the mechanisms involved in its occurrence for the successful treatment of infections caused by this organism

Phenotype and genetic determination of resistance to common disinfectants among bioflm-producing and non-producing Pseudomonas aeruginosa strains from clinical specimens in Iran

Background: Pseudomonas aeruginosa is a common pathogen in Hospitalized patients, and its various resistance mechanisms contribute to patient morbidity and mortality. The main aims of the present study were to assess the susceptibility of bioflm-producing and non-producing P. aeruginosa isolates to the fve commonly used Hospital disinfectants, to evaluate the synergistic efect of selected disinfectants and Ethylene-diamine-tetra acetic acid (EDTA), and the efect of exposure to sub-inhibitory concentrations of Sodium hypochlorite on antimicrobial susceptibility test. Results: The results showed that sodium hypochlorite 5% and Ethanol 70% were the most and least efective disinfectants against P. aeruginosa, respectively. The addition of EDTA signifcantly increased the efectiveness of the selected disinfectants. The changes in the antibiotic-resistance profles after exposure to sub-inhibitory concentrations of disinfectants were observed for diferent classes of antibiotics (Carbapenems, Aminoglycosides, Cephalosporins, Fluoroquinolones). As well as near the all isolates harbored efux pump genes and 117 (97.5%) of isolates produced bioflm. Conclusion: In the current study, the mixture of disinfectant and EDTA were the most suitable selection to disinfect Hospital surfaces and instruments. Also, it was clear that exposure to sub-inhibitory concentrations of Sodium hypochlorite results in resistance to some antibiotics in P. aeruginosa species. Strong and intermediate bioflm formers belonged to MDR/XDR strains. Future studies should include more complex microbial communities residing in the Hospitals, and more disinfectants use in Hospitals. Keywords: Nosocomial infection, Disinfectant-resistance, Bioflm, Hospital disinfectants, Pseudomonas aeruginosa, Clinical isolate

Emergence of plasmid-mediated quinolone-resistant determinants in Klebsiella pneumoniae isolates from Tehran and Qazvin provinces, Iran

Background. Plasmid-mediated quinolone resistance is an increasing clinical concern, globally. The major objective of the present study was to identify the qnr-encoding genes among the quinolone non-susceptible K. pneumoniae isolates obtained from two provinces in Iran. Methods. A total of 200 K. pneumoniae isolates were obtained from hospitals of Qazvin and Tehran, Iran. The identification of bacterial isolates was carried out by standard laboratory methods and API 20E strips. Susceptibility to quinolone compounds were examined by standard Kirby-Bauer disk diffusion method according to the CLSI guideline. PCR and sequencing were employed to detect qnrA, qnrB and qnrS-encoding genes. Results. Of 200 K. pneumoniae isolates, 124 (62%) were nonsusceptible to quinolone compounds among those 66 (53.2%) and 58 (46.8%) isolates showed high and low-level quinolone resistance rates, respectively. Out of 124 quinolone non-susceptible isolates, qnr-encoding genes were present in 49 (39.5%) isolates with qnrB1 (30.6%) as the most dominant gene followed by qnrB4 (9.7%), and qnrS1 (1.6%) either alone or in combination. Conclusions. This study, for the first time, revealed the high appearance of qnrB1, qnrS1 and qnrB4 genes among the clinical isolates of K. pneumoniae in Iran. Therefore, the application of proper infection control measures and well-established antibiotic administration guideline should be strictly considered within our medical centers

Biodegradation of Paraoxan as an Organophosphate Pesticide with Pseudomonas plecoglocissida Transfected by opd Gene

Background: Organophosphate pesticides (OP) are applied to agricultural farms and can be carried away into closely sewerage and gullies, which consequently carry water to rivers and lakes and when distributed in the environment they become polluted and require remediation. Objectives: The current study aimed at producing a genetically engineered Pseudomonas plecoglossicida capable of biodegradation of the organophosphate pesticides, paraoxon. Methods: Genetically engineered P. plecoglossicida was initially made by transferring polymerase chain reaction (PCR) product of opd gene from Flavobacterium sp. ATCC 27551 into the chromosome of P. plecoglossicida. Results: The constructed strain could hydrolyze paraoxon to p-nitrophenol and di-ethylphosphate in paraoxon supplemented in complete supplement mixture (CSM) medium. The isolate could use paraoxon as the only source of carbon. Thus, the bacteria degraded the organophosphate pesticides, and utilized nutrient products of their degradation. Conclusions: The observed versatility of genetically engineered P. plecoglossicida in biodegradation of xenobiotics suggested that this strain may be useful for the multipurpose bioremediation of contaminated agricultural and industrial sites. Keywords: Organophosphates; Pesticide; Bioremediation; Pseudomonas plecoglossicid