Deciphering the structure of a multi-drug resistant Acinetobacter baumannii short-chain dehydrogenase reductase.

The rapidly increasing threat of multi-drug-resistant Acinetobacter baumannii infections globally, encompassing a range of clinical manifestations from skin and soft tissue infections to life-threatening conditions like meningitis and pneumonia, underscores an urgent need for novel therapeutic strategies. These infections, prevalent in both hospital and community settings, present a formidable challenge to the healthcare system due to the bacterium's widespread nature and dwindling effective treatment options. Against this backdrop, the exploration of bacterial short-chain dehydrogenase reductases (SDRs) emerges as a promising avenue. These enzymes play pivotal roles in various critical bacterial processes, including fatty acid synthesis, homeostasis, metabolism, and contributing to drug resistance mechanisms. In this study, we present the first examination of the X-ray crystallographic structure of an uncharacterized SDR enzyme from A. baumannii. The tertiary structure of this SDR is distinguished by a central parallel ß-sheet, consisting of seven strands, which is flanked by eight α-helices. This configuration exhibits structural parallels with other enzymes in the SDR family, underscoring a conserved architectural theme within this enzyme class. Despite the current ambiguity regarding the enzyme's natural substrate, the importance of many SDR enzymes as targets in anti-bacterial agent design is well-established. Therefore, the detailed structural insights provided in this study open new pathways for the in-silico design of therapeutic agents. By offering a structural blueprint, our findings may provide a platform for future research aimed at developing targeted treatments against this and other multi-drug-resistant infections.

Crystallographic structure determination and analysis of a potential short-chain dehydrogenase/reductase (SDR) from multi-drug resistant Acinetobacter baumannii.

Bacterial antibiotic resistance remains an ever-increasing worldwide problem, requiring new approaches and enzyme targets. Acinetobacter baumannii is recognised as one of the most significant antibiotic-resistant bacteria, capable of carrying up to 45 different resistance genes, and new drug discovery targets for this organism is an urgent priority. Short-chain dehydrogenase/reductase enzymes are a large protein family with >60,000 members involved in numerous biosynthesis pathways. Here, we determined the structure of an SDR protein from A. baumannii and assessed the putative co-factor comparisons with previously co-crystalised enzymes and cofactors. This study provides a basis for future studies to examine these potential co-factors in vitro.

Structural characterisation of hemagglutinin from seven Influenza A H1N1 strains reveal diversity in the C05 antibody recognition site.

Influenza virus (IV) causes several outbreaks of the flu each year resulting in an economic burden to the healthcare system in the billions of dollars. Several influenza pandemics have occurred during the last century and estimated to have caused 100 million deaths. There are four genera of IV, A (IVA), B (IVB), C (IVC), and D (IVD), with IVA being the most virulent to the human population. Hemagglutinin (HA) is an IVA surface protein that allows the virus to attach to host cell receptors and enter the cell. Here we have characterised the high-resolution structures of seven IVA HAs, with one in complex with the anti-influenza head-binding antibody C05. Our analysis revealed conserved receptor binding residues in all structures, as seen in previously characterised IV HAs. Amino acid conservation is more prevalent on the stalk than the receptor binding domain (RBD; also called the head domain), allowing the virus to escape from antibodies targeting the RBD. The equivalent site of C05 antibody binding to A/Denver/57 HA appears hypervariable in the other H1N1 IV HAs. Modifications within this region appear to disrupt binding of the C05 antibody, as these HAs no longer bind the C05 antibody by analytical SEC. Our study brings new insights into the structural and functional recognition of IV HA proteins and can contribute to further development of anti-influenza vaccines.

Structural characterization of a Type B chloramphenicol acetyltransferase from the emerging pathogen Elizabethkingia anophelis NUHP1.

Elizabethkingia anophelis is an emerging multidrug resistant pathogen that has caused several global outbreaks. E. anophelis belongs to the large family of Flavobacteriaceae, which contains many bacteria that are plant, bird, fish, and human pathogens. Several antibiotic resistance genes are found within the E. anophelis genome, including a chloramphenicol acetyltransferase (CAT). CATs play important roles in antibiotic resistance and can be transferred in genetic mobile elements. They catalyse the acetylation of the antibiotic chloramphenicol, thereby reducing its effectiveness as a viable drug for therapy. Here, we determined the high-resolution crystal structure of a CAT protein from the E. anophelis NUHP1 strain that caused a Singaporean outbreak. Its structure does not resemble that of the classical Type A CATs but rather exhibits significant similarity to other previously characterized Type B (CatB) proteins from Pseudomonas aeruginosa, Vibrio cholerae and Vibrio vulnificus, which adopt a hexapeptide repeat fold. Moreover, the CAT protein from E. anophelis displayed high sequence similarity to other clinically validated chloramphenicol resistance genes, indicating it may also play a role in resistance to this antibiotic. Our work expands the very limited structural and functional coverage of proteins from Flavobacteriaceae pathogens which are becoming increasingly more problematic.

Formulation, Standardization, and a Preliminary Before-After Clinical Trial on Effect of a Traditional Herbal Formula (Maqliasa) on Manifestations of Ulcerative Colitis.

BACKGROUND: Ulcerative Colitis (UC) is a chronic condition that represents a group of intestinal disorders causing prolonged inflammation of the digestive tract. Nowadays, efforts to investigate new remedies have led to a committed movement toward the integration of traditional and complementary medicine into mainstream medicine. In Traditional Persian Medicine (TPM), Maqliasa is one of the most frequent gastrointestinal prescriptions which is claimed to be effective in both remission and recurrent phases of UC. OBJECTIVE: The aim of this pilot study was to examine the effect of Maqliasa on UC symptoms. METHODS: Through a non-randomized before-after uncontrolled clinical trial, 13 outpatients with active UC were enrolled in the study. They continued their conventional drug regimens plus Maqliasa capsules (2 capsules t.i.d.) for 28 days. Three visits were arranged for each patient- the first admission, day 14th admission and day 28th admission. The patients were evaluated by Lichtiger Colitis Activity Index. Wilcoxon signed-rank test was used for statistical analysis. RESULTS: The Lichtiger colitis activity index improved in the study group was compared to the corresponding baseline values: baseline score: 7.8 ± 0.5; after two weeks: 5.9 ± 0.6 (P=0.002); after four weeks: 3.6 ± 0.5 (P=0.001). CONCLUSIONS: This study showed the promising effect of Maqliasa in the treatment of active UC. However, due to some of the limitations of the study, conducting future high-quality randomized clinical trials would be crucial.

Antimutagenic and Synergistic Cytotoxic Effect of Cisplatin and Honey Bee Venom on 4T1 Invasive Mammary Carcinoma Cell Line.

INTRODUCTION: Honey bee venom (HBV) has various biological activities such as the inhibitory effect on several types of cancer. Cisplatin is an old and potent drug to treat most of the cancers. Our aim in the present study was to determine antimutagenic and cytotoxic effects of HBV on mammary carcinoma, exclusively and in combination with cisplatin. METHODS: In this study, 4T1 cell line was cultured in RPMI-1640 with 10% fetal bovine serum (FBS), at 37°C in humidified CO2 incubator. The cell viabilities were examined by the MTT assay. Also, HBV was screened for its antimutagenic activity via the Ames test. The results were assessed by SPSS software version 19 and one-way ANOVA method considering p < 0.05 level of significance. RESULTS: The results showed that 6 mg/ml of HBV, 20 µg/ml of cisplatin, and 6 mg/ml HBV with 10 µg/ml cisplatin could induce approximately 50% of 4T1 cell death. The concentration 7 mg/ml of HBV with of 62.76% inhibitory rate showed the highest antimutagenic activity in comparison with other treatment groups. CONCLUSIONS: The MTT assay demonstrated that HBV and cisplatin could cause cell death in a dose-dependent manner. The cytotoxic effect of cisplatin also promoted by HBV. Ames test outcomes indicated that HBV could act as a significant mutagenic agent. The antimutagenic activity of HBV was increased considerably in the presence of S9 mix. Therefore, our findings have revealed that HBV can enhance the cytotoxic effect of cisplatin drug and its cancer-preventing effects.

Reliability and validity of the Persian version of patient assessment of constipation- quality of life (PAC-QOL) questionnaire.

AIM: The present study aimed to assess the reliability and validity of Persian version of patient assessment of constipation: quality of life (PAC-QOL) questionnaire in Iranian patients. BACKGROUND: Chronic constipation has significant effects on daily living, wellbeing and individuals' quality of life (QOL). Validated tools can help us to assessing QOL in affected ones and facilitating clinical management of them. METHODS: The English version of Patient Assessment of Constipation: Quality of Life (PAC-QOL) was translated into the Persian language and was confirmed by back-translation. One hundred and forty patients with functional constipation, according Rome III criteria, completed the questionnaires .The questionnaires were analyzed using Cronbach's Alpha internal consistency score to determine the reliability. Twenty medical experts were then asked to evaluate the PAC-QOL and the results were used to calculate the Content Validity Ratio (CVR) and Content Validity Index (CVI). RESULTS: Due to obtained value for Cronbach`s α (0.975) and also for the subscale of physical discomfort (0.930), psychosocial discomfort (0.975) and worries and concerns (0.915), the internal consistency is established. According to medical experts' opinions, the value of CVR ranged from 0.5 to 0.8 and the value of CVI was 0.81. CONCLUSION: The Persian version of PAC-QOL questionnaire is shown to have acceptable reliability and validity to be used for psychometric evaluation in Iranian patients complaining of functional constipation.

Comparison of quinolone and beta-lactam resistance among Escherichia coli strains isolated from urinary tract infections.

The growing frequency of antibiotic resistances is now a universal problem. Increasing resistance to new generations of ß-lactam and quinolone antibiotics in multidrug-resistant Enterobacteriaceae isolates is considered an emergency health issue worldwide. The aim of this study was to evaluate plasmid-mediated quinolone resistance genes in ESBL-producing Escherichia coli isolated from urinary tract infections (UTIs). In our study ESBL-producing isolates were assessed by screening methods. After determination of antimicrobial susceptibility testing, detection of ESBLs and quinolone resistance genes was performed. A total of 97 ESBL-producing E. coli were determined. The bla-TEM, bla-SHV and bla-CTX-M genes were detected in 90 isolates. The bla-TEM was the most frequently detected gene (46.4%), followed by bla-SHV (31.9%) and bla-CTX-M (14.4%). The most prevalent quinolone resistance gene among ESBL-producing isolates was oqxAB which was found in 67 isolates (69.1%). The frequencies of the aac(6')-Ib-cr, qnr and qepA were 65 (67%), 8 (8.2%) and 6 (6.2%), respectively. Our data indicate that the prevalence of plasmid-mediated quinolone resistance genes in ESBL-positive isolates is increasing. The co-dissemination of PMQR and ESBL genes among E. coli isolates can be considered a threat to public health. Therefore, prescription of antibiotics against infectious disease should be managed carefully.

Fever,Weight Loss and Early Satiety due to Gastric Inflammatory Myofibroblastic Tumor; Case Report and Literature Review.

Gastric inflammatory myofibroblastic tumor (IMT) is a rare tumor with and unpredictable prognosis usually find in young adults. We present an 18-yearold man with gastric IMT. He complained of epigastric pain, intermittent fever and night sweating associated with weight loss since two years ago. Physical examination showed anemic and cachestic features with mild abdominal tenderness in palpitation as well as an abdominal mass in epigastrium. Abdominal CT scan revealed a huge mass that was arising from the stomach. Upper endoscopy revealed a submucosal lesion in fundus of stomach of approximately 8cm. Endoscopic ultrasound showed a large sub-mucosal non homogenous fundal mass with areas of calcification. The patient underwent laparoscopic partial gastrectomy. Histopathologyand immunohistochemistryevaluation revealed an IMT.

Efficacy of Clarithromycin Containing Bismuth-Based Regimen as a Second-Line Therapy in Helicobacter Pylori Eradication.

BACKGROUND The eradication of Helicobacter pylori infection, commonly prevailing in the stomach, has been important since its introduction. Adequate preparations should be made in finding alternatives when faced with first-line treatment failures. Currently, ideal second-line treatments are indistinct and varied among countries as result of different antibiotic resistance patterns. We aimed to evaluate the safety and efficacy of a clarithromycin-containing bismuth-based quadruple regimen as a second-line treatment. METHODS Forty-eight H.pylori-positive patients with proven gastric or duodenal ulcers and/or erosions who had previously failed to respond to furazolidone-containing regimens were enrolled. They received pantoprazole (40 mg-bid), amoxicillin (1gr-bid), bismuth subcitrate (240 mg-bid), and clarithromycin (500mg-bid) for 10 days. Eight weeks after treatment, a (14)C-urea breath test was performed for the re-evaluation of H. pylori eradication. RESULTS Forty-three patients completed the study. H.pylori eradication rates were 79.2% (95% CI=65.00-89.53) and 88.4% (95% CI=74.91-96.11) according to intention-to-treat and per-protocol analyses, respectively. All patients had excellent compliance to treatment and one did not continue therapy because of adverse effects. CONCLUSION In developing countries such as Iran, a ten-day clarithromycin-containing bismuth-based quadruple regimen is encouraged as a second-line treatment because of the acceptable rate of eradication and low adverse effects.