A critical review of novel antibiotic resistance prevention approaches with a focus on postbiotics.

Antibiotic resistance is a significant public health issue, causing illnesses that were once easily treatable with antibiotics to develop into dangerous infections, leading to substantial disability and even death. To help fight this growing threat, scientists are developing new methods and techniques that play a crucial role in treating infections and preventing the inappropriate use of antibiotics. These effective therapeutic methods include phage therapies, quorum-sensing inhibitors, immunotherapeutics, predatory bacteria, antimicrobial adjuvants, haemofiltration, nanoantibiotics, microbiota transplantation, plant-derived antimicrobials, RNA therapy, vaccine development, and probiotics. As a result of the activity of probiotics in the intestine, compounds derived from the structure and metabolism of these bacteria are obtained, called postbiotics, which include multiple agents with various therapeutic applications, especially antimicrobial effects, by using different mechanisms. These compounds have been chosen in particular because they don't promote the spread of antibiotic resistance and don't include substances that can increase antibiotic resistance. This manuscript provides an overview of the novel approaches to preventing antibiotic resistance with emphasis on the various postbiotic metabolites derived from the gut beneficial microbes, their activities, recent related progressions in the food and medical fields, as well as concisely giving an insight into the new concept of postbiotics as "hyperpostbiotic".

Comparing proteome changes involved in biofilm formation by Streptococcus mutans after exposure to sucrose and starch.

Streptococcus mutans is a main organism of tooth infections including tooth decay and periodontitis. The aim of this study was to assess the influence of sucrose and starch on biofilm formation and proteome profile of S. mutans ATCC 35668 strain. The biofilm formation was assessed by microtiter plating method. Changes in bacterial proteins after exposure to sucrose and starch carbohydrates were analyzed using matrix-assisted laser desorption/ionization mass spectrometry. The biofilm formation of S. mutans was increased to 391.76% in 1% sucrose concentration, 165.76% in 1% starch, and 264.27% in the 0.5% sucrose plus 0.5% starch in comparison to biofilm formation in the media without sugars. The abundance of glutamines, adenylate kinase, and 50S ribosomal protein L29 was increased under exposure to sucrose. Upregulation of lactate utilization protein C, 5-hydroxybenzimidazole synthase BzaA, and 50S ribosomal protein L16 was formed under starch exposure. Ribosome-recycling factor, peptide chain release factor 1, and peptide methionine sulfoxide reductase MsrB were upregulated under exposure to sucrose in combination with starch. The results demonstrated that the carbohydrates increase microbial pathogenicity. In addition, sucrose and starch carbohydrates can induce biofilm formation of S. mutans via various mechanisms such as changes in the expression of special proteins.

Clostridium species diversity in gut microbiota of patients with renal failure.

The Pathology of digestive tract has long been known to be correlated with chronic kidney disease (CKD). The member of the major Firmicutes phylum especially Clostridium subcluster XIVa altered quantitatively and qualitatively in the gut microbiota of patients with End Stage Renal Disease (ESRD) and CKD. Therefore, in this study, the abundance of the species of Clostridium genus of Firmicutes phylum compared between intestine microbiota of patients with kidney failure and healthy individual. Fresh fecal specimens of 20 patients at different stages of CKD and 20 healthy individuals were collected. Bacterial DNA of samples were extracted to use for 16S ribosomal DNA sequencing targeting the V3-V4 region. Next generation sequencing (NGS) method at MiSeq system was used to find the diversity of gut microbiota composition. Totally, 11 (1.68%) of 651 bacterial strains which were isolated from forty fecal samples of both healthy volunteers and CKD/ESRD patients, were identified as Clostridium species. Eight genera of 11 Clostridium genera were related to Clostridium sensu stricto, and 3 other genera were as follows Vallitalea, Acidaminobacter and Caloramator. Among both group, the highest abundance was dedicated to Clostridium celatum genera. Sarcina maxima were not identified. The composition of Clostridium spp. showed the same frequency among CKD/ESRD and healthy groups (p < 0.05). The abundance of Clostridium spp. is virtually the same and not differs among healthy individuals and CKD/ESRD patients. Results of the present indicate despite of critical role of gut microbiota, some pathogens and their metabolites have no role on hemostasis and pathogenesis of kidney disorders.

Induction of proteome changes involved in biofilm formation of Enterococcus faecalis in response to gentamicin.

BACKGROUND: Enterococcus faecalis is a significant cause of nosocomial infections and other diseases, including endocarditis, bacteremia, and urinary tract infections. This microorganism forms biofilms to overcome difficult environmental conditions, such as lack of oxygen, lack of water, and the presence of antimicrobials. These biofilms make diseases difficult by changing their proteome contents, protecting the bacterium, and increasing their pathogenicity. This study aimed to evaluate gentamicin's effect on proteome changes and biofilm formation in E. faecalis. METHOD: Twenty-five clinical isolates and one standard isolate were selected for the experiments. A label-free/gel-free proteomic and microtiter plate techniques were used to study proteome changes and biofilm formation, respectively. RESULTS: Gentamicin significantly increased the biofilm formation in 62% of isolates and the rest of the isolates; no significant change was observed. The abundance of lactate utilization protein C, ribosomal RNA small subunit methyltransferase H, and protein translocase subunit SecA were increased. However, the abundances of proteins effective in cell division and metabolism, such as replication initiation protein and segregation and condensation protein A, were decreased. CONCLUSION: The present study's findings exhibited that antibiotics might have adverse effects on treatment and increase microorganisms' pathogenicity. It was observed in gentamicin as induction of biofilm formation through different mechanisms, particularly changes in the expression of specific proteins in E. faecalis.

AdeB efflux pump gene knockdown by mRNA mediated peptide nucleic acid in multidrug resistance Acinetobacter baumannii.

Multidrug-resistant Acinetobacter baumannii isolates cause critical problems in health-care environments. AdeABC is a resistance-nodulation-cell division (RND)-type multidrug efflux pump conferring resistance to clinically essential antibiotics in A. baumannii, such as ciprofloxacin. This study aimed to target adeB gene with antisense peptide nucleic acid (PNA) and investigate its effect on resistance to antibiotics. NCBI database was used to design appropriate PNA to target adeB gene, by connecting PNA to mRNA, the translation of mRNA can be prevented. Three clinical isolates and A. baumannii ATCC 17978 were treated with the designed PNA by electroporation and competence procedure. Minimum Inhibitory concentration (MIC) of ciprofloxacin, colistin, and tetracycline were determined by microbroth dilution method. In addition, the expression level of adeB gene was measured by quantitative real-time PCR (qRT-PCR). Isolates used in this study had mutations in gyrA and parC genes corresponding to resistance to ciprofloxacin. MIC of resistance to ciprofloxacin after treatment with PNA was reduced from 32 µg/ml to16 µg/ml in A. baumannii ATCC 17978 isolate. Susceptibility level of tetracycline, in the 2 clinical isolates was decreased from 64 µg/ml to 32 µg/ml and in the other isolate was reduced from 128 µg/ml to 64 µg/ml. The expression level of adeB gene was decreased in A. baumannii ATCC 17978 (P > 0.01) but not in clinical isolate (P = 0.107). Findings of the present study indicate overexpression of adeB efflux pump has extra effect on resistance to antibiotics in isolates with a defined mechanism of resistance. Antisense technology is a feasible technique to suppress the function of these genes, which may be further exploited to control multidrug-resistant isolates.

Antisense peptide nucleic acids againstftsZ andefaA genes inhibit growth and biofilm formation of Enterococcusfaecalis.

Enterococcus faecalis is one of the important causes of nosocomial infections. Nowadays, increasing prevalence of antibiotic-resistant bacteria and slow progress in recognizing new antimicrobial agents has limited the efficiency of conventional antibiotics, which cause to find novel strategies to overcome bacteria. Therefore, in this study, we aimed to assess the role of efaA gene in the biofilm formation and the role of ftsZ gene in the controlling of bacterial growth by the anti-sense PNAs(Peptide Nucleic Acid).E. faecalis ATCC® 29212™was used for the study of PNAs designed to targeting the start codon section of the ftsZ andefaA genes. PNA attachment to RNA was confirmed by blotting. Electroporation technique was used for the intracellular transfer of anti-ftsZ PNAs. The spot-plating method was used to the assessment of alteration in bacterial growth. Biofilm formation assay and real-time PCR were used for detection of biofilm inhibitory effect of cell penetrating peptide (CPP) conjugated to anti-efaA PNAs.ByftsZ PNAs treatment, no growth was seen from the strain in agar by a spot plating method and the inhibition zone of anti-ftsZ PNAs was not seen. PNAs against the efaA gene decreased by 95% the expression of the efaA gene and biofilm formation. In addition, the(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) MTT assay showed no toxicity on MCF7 cells for both of anti-ftsZand anti-efaA PNAs.This study used new genetic and molecular tools to inhibit pathogenicity and infection by E. faecalis. In this study, we suggested that efaA gene plays a critical role in the biofilm formation and anti-efaA PNAs could decrease the formation of biofilm, as well as, anti-ftsZ PNAs could eliminate bacterial growth.

Microbial balance in the intestinal microbiota and its association with diabetes, obesity and allergic disease.

Recent studies have been considered to symbiotic interactions of the human gastrointestinal microbiota and human lifestyle-related disorders. The human gastrointestinal microbiota continuously stimulates the immune system against opportunistic and pathogen bacteria from infancy. Changes in gastrointestinal microbiota have been associated with numbers of human diseases such as allergic diseases, autoimmune encephalitis, atherosclerosis, colorectal cancer, obesity, diabetes etc. In this review article, we evaluate studies on the roles of human gastrointestinal microbiota and interference pathogenicity in allergic diseases, obesity, and diabetes. Several studies indicated association between allergic diseases and changes in bacterial balance such as increased of Clostridium spp., some species of Bifidobacterium spp., or decreased of Bacteroidetes phylum and some species of Bifiobacterium spp. and production of specific short-chain fatty acids due to food type, delivery modes of infant, infant evolvement environment and time of getting bacteria at an early-life age. In addition, obesity and diabetes are associated with food type, production of short chain fatty acids undergo fermentation of the intestinal microbiota, metabolic endotoxemia, endocannabinoid system and properties of the immune system. Well-characterized underlying mechanisms may provide novel strategies for using prebiotic and probiotic to prevent and treatment of allergic diseases, obesity, diabetes, and other lifestyle-related disorders.

Laboratory Cross-Contamination of Mycobacterium tuberculosis: A Systematic Review and Meta-analysis.

BACKGROUND: Microbiological cultures are the mainstay of the diagnosis of tuberculosis (TB). False-positive TB results lead to significant unnecessary therapeutic and economic burden and are frequently caused by laboratory cross-contamination. The aim of this meta-analysis was to quantify the prevalence of laboratory cross-contamination. METHODS: Through a systematic review of five electronic databases, we identified studies reporting rates of laboratory cross-contamination, confirmed by molecular techniques in TB cultures. We evaluated the quality of the identified studies using the National Institute of Health (NIH) Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies, and conducted a meta-analysis using standard methodology recommended by the Cochrane Collaboration. RESULTS: Based on 31 eligible studies evaluating 29,839 TB cultures, we found that 2% (95% confidence intervals [CI] 1-2%) of all positive TB cultures represent false-positive results secondary to laboratory cross-contamination. More importantly, we evaluated the rate of laboratory cross-contamination in cases where a single-positive TB culture was available in addition to at least one negative TB culture, and we found a rate of 15% (95% CI 6-33%). Moreover, 9.2% (91/990) of all patients with a preliminary diagnosis of TB had false-positive results and received unnecessary and potentially harmful treatments. CONCLUSIONS: Our results highlight a remarkably high prevalence of false-positive TB results as a result of laboratory cross-contamination, especially in single-positive TB cultures, leading to the administration of unnecessary, harmful treatments. The need for the adoption of strict technical standards for mycobacterial cultures cannot be overstated.

Docosahexaenoic acid attenuates the detrimental effect of palmitic acid on human endothelial cells by modulating genes from the atherosclerosis signaling pathway.

The formation of atherosclerotic changes leads to dysfunction in numerous cell types, especially endothelial cells. In the current experiment, we aimed to show the therapeutic effect of Docosahexaenoic acid on palmitic-induced atherosclerotic changes in the human endothelial lineage. Human Umbilical Vein Endothelial cells were incubated with 1 mM palmitic acid for 48 hours and then exposed to 40 µM docosahexaenoic acid for next 24 hours. Cellular atherosclerosis and lipid removal were confirmed by the application of Oil red O solution. The cell survival rate was studied by using MTT assay and flow cytometry analysis of Annexin V. We also measured the protein level of tumor necrosis factor-α and granulocyte-macrophage colony-stimulating factor by immunofluorescence imaging. The transcription level of genes participating in the atherosclerosis signaling pathway was monitored in atherosclerotic endothelial cells before and after treatment with docosahexaenoic acid. The viability of the cells was reduced after 48 hours incubation with palmitic acid. It is noteworthy that the number of viable endothelial cells was increased after exposure to docosahexaenoic acid. Compared with the cells that received palmitic acid, Oil red O staining showed a decrease in the cellular content of fatty acid after incubation with docosahexaenoic acid (P < 0.05). PCR array indicated that the modulation of key genes played a role in atherosclerosis and reached near-control levels. These data support the notion that incubation of atherosclerotic human endothelial cells with docosahexaenoic acid could return the detrimental effects of palmitic acid by modulation of the atherosclerosis signaling pathway.

Frequency of Smear-Negative Tuberculosis in Northwest Iran.

BACKGROUND: Microscopic smear examination is the most common test in tuberculosis (TB) detection. It is, however, not strong enough to identify TB in the majority of afflicted individuals; thus, a significant number of TB patients are smear negative and capable of transmitting the infection. The aim of this study was to evaluate the rate of smear-negative TB in northwest Iran. METHODS: In this cross-sectional study, 329 TB-confirmed patients were evaluated through culture up to March 1, 2015, in northwest Iran. The demographic and clinical features of the smear-negative and smear-positive TB patients were compared. The χ2 test was used to compare the frequency of the variables. All the statistical analyses were conducted using SPSS, version 16 (Chicago, IL, USA). RESULTS: Seventy-five cases were smear negative and 254 were smear positive. Smokers, asthmatics, and extra-pulmonary TB patients were primarily among the smear-negative cases. The rate of mortality was also relatively higher among the smear-negative TB patients. CONCLUSION: Totally, 22.8% of the TB cases in northwest Iran were smear negative, with a relatively higher rate of mortality than those with positive smears. A delay in these patients' return to TB diagnosis and treatment centers increases the chance of transmission to others. This is a very sensitive issue in centers where there is no equipment for TB cultivation. Thus, it is essential to equip centers without TB cultivation facilities and to use appropriate diagnostic techniques in centers with those facilities to help rapidly detect smear-negative cases.

Linezolid: a promising option in the treatment of Gram-positives.

Linezolid, an oxazolidinone antimicrobial agent that acts by inhibiting protein synthesis in a unique fashion, is used in the treatment of community-acquired pneumonia, skin and soft-tissue infections and other infections caused by Gram-positive bacteria including VRE and methicillin-resistant staphylococci. Currently, linezolid resistance among these pathogens remains low, commonly <1.0%, although the prevalence of antibiotic resistance is increasing in many countries. Therefore, the development of resistance by clinical isolates should prompt increased attention of clinical laboratories to routinely perform linezolid susceptibility testing for this important agent and should be taken into account when considering its therapeutic use. Considering the importance of linezolid in the treatment of infections caused by Gram-positive bacteria, this review was undertaken to optimize the clinical use of this antibiotic.

The role of gut microbiota and probiotics in preventing, treating, and boosting the immune system in colorectal cancer.

The gut microbiome plays a significant role in developing colorectal cancer (CRC). The gut microbiome usually acts as a protective barrier against harmful pathogens and infections in the intestine, while also regulating inflammation by affecting the human immune system. The gut microbiota and probiotics play a role not only in intestinal inflammation associated with tumor formation but also in regulating anti-cancer immune response. As a result, they associated with tumor progression and the effectiveness of anti-cancer therapies. Research indicates that gut microbiota and probiotics can be used as biomarkers to predict the impact of immunotherapy and enhance its efficacy in treating CRC by regulating it. This review examines the importance of gut microbiota and probiotics in the development and progression of CRC, as well as their synergistic impact on anti-cancer treatments.

Antibody humanization methods - a review and update.

This article reviews recent advances achieved during recent years on various aspects of antibody humanization theories and techniques. Common methods for producing humanized antibodies including framework-homology-based humanization, germline humanization, complementary determining regions (CDR)-homology-based humanization and specificity determining residues (SDR) grafting, as well as advantages and disadvantages of each of these methods and their applications are discussed.

Chronic kidney disease and gut microbiota.

Chronic kidney disease (CKD) refers to a range of various pathophysiological processes correlated with abnormal renal function and a progressive loss in GFR. Just as dysbiosis and altered pathology of the gut are accompanied with hypertension, which is a significant CKD risk factor. Gut dysbiosis in CKD patients is associated with an elevated levels of uremic toxins, which in turn increases the CKD progression. According to research results, the gut-kidney axis has a role in the formation of kidney stones, also in IgAN. A number of researchers have categorized the gut microbiota as enterotypes, and others, skeptical of theory of enterotypes, have suggested biomarkers to describe taxa that related to lifestyle, nutrition, and disease status. Metabolome-microbiome studies have been used to investigate the interactions of host-gut microbiota in terms of the involvement of metabolites in these interactions and are yielded promising results. The correlation between gut microbiota and CKD requires further multi-omic researches. Also, with regard to systems biology, studies on the communication network of proteins and transporters such as SLC and ABC, can help us achieve a deeper understanding of the gut-liver-kidney axis communication and can thus provide promising new horizons in the treatment of CKD patients. Probiotic-based treatment is an approach to reduce uremic poisoning, which is accomplished by swallowing microbes those can catalyze URS in the gut. If further comprehensive studies are carried out, we will know about the probiotics impact in slowing the renal failure progression and reducing inflammatory markers.

COVID-19, HIV, and Cryptococcal Meningitis Coinfections with Abnormal Laboratory Findings.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first introduced in China in 2019, and it has rapidly spread all around the world. Cryptococcus neoformans is the leading cause of fungal meningitis in human immunodeficiency virus- (HIV-) infected patients. A variety of laboratory tests have been introduced for rapid diagnosis of meningitis. Methods: Here, we report a case of coinfection with COVID-19 and cryptococcal meningitis in a HIV-positive patient with abnormal laboratory findings. In this case, COVID-19 was positive by polymerase chain reaction (PCR) and computerized tomography (CT) scan diagnosis. Cryptococcal antigen testing of CSF was negative, whereas India ink staining and cerebrospinal fluid (CSF) culture confirmed the presence of C. neoformans. Results: Although the patient was in a critical stage of illness, serum and CSF levels of procalcitonin were abnormally low, within normal limits. On the other hand, although initial lumbar puncture had showed elevated protein level, the repeat CSFs presented remarkably reduced protein levels. Our findings indicate that despite COVID-19 infection, procalcitonin level may remain normal in HIV-associated cryptococcal meningitis, and findings of an apparently normal procalcitonin level should not exclude the possibility of infection. Also, antigen testing may present false-negative result, and it should not be the sole laboratory method for diagnosis of infectious meningitis. Consequently, CSF culture and staining is recommended, even when antigen testing of organism is negative and CSF profile is unremarkable. Conclusion: Laboratory information should be combined with a good understanding of clinical manifestations of patient to determine if meningitis is present and confirmed COVID-19 should not ignore possibility of other infections for consideration.

Natural Products as a Potential Source of Promising Therapeutics for COVID-19 and Viral Diseases.

Background: A global pandemic has recently been observed due to the new coronavirus disease, caused by SARS-CoV-2. Since there are currently no antiviral medicines to combat the highly contagious and lethal COVID-19 infection, identifying natural sources that can either be viricidal or boost the immune system and aid in the fight against the disease can be an essential therapeutic support. Methods: This review was conducted based on published papers related to the herbal therapy of COVID-19 by search on databases including PubMed and Scopus with herbal, COVID-19, SARS-CoV-2, and therapy keywords. Results: To combat this condition, people may benefit from the therapeutic properties of medicinal plants, such as increasing their immune system or providing an antiviral impact. As a result, SARS-CoV-2 infection death rates can be reduced. Various traditional medicinal plants and their bioactive components, such as COVID-19, are summarized in this article to assist in gathering and debating techniques for combating microbial diseases in general and boosting our immune system in particular. Conclusion: The immune system benefits from natural products and many of these play a role in activating antibody creation, maturation of immune cells, and stimulation of innate and adaptive immune responses. The lack of particular antivirals for SARS-CoV-2 means that apitherapy might be a viable option for reducing the hazards associated with COVID-19 in the absence of specific antivirals.

Diversity of Bacteroidaceae family in gut microbiota of patients with chronic kidney disease and end stage renal disease.

Background: Human intestine microbiota are known to be directly and indirectly altered during some diseases such as kidney complications. Bacteroides is considered as the main and the most abundant phylum among human gut microbiota, which has been classified as enterotype 1. This study aimed to assess the abundance of Bacteroides spp. in fecal flora of end-stage renal disease (ESRD) and chronic kidney disease (CKD) patients and compare it with the Bacteroides composition among fecal flora of healthy individual. Methods: Fresh fecal samples were collected from 20 CKD/ESRD patients and 20 healthy individual without any kidney complications. The pure microbial DNA was extracted by QIAamp Stool Mini Kit from stool samples. MiSeq system was used to analyze the intestinal composition by next generation sequencing method. Results: A number of 651 bacterial strains were isolated and identified from 40 fecal samples of both patients and healthy groups. Bioinformatics analysis defined 18 different types of Bacteroides species which included 2.76% of all strains. Statistical analysis showed no significant difference between study groups (P>0.05). In both healthy and patient groups three species including B. dorei, B. uniformis, and B. ovatus have allocated the most abundance to themselves. The lowest abundance was related to B. eggerthii, A. furcosa and B. barnesiae among CKD/ESRD patients and A. furcosa, B. barnesiae, and B. coprocola had the lowest abundance among healthy people. Conclusion: This study indicates despite all previous evidence of Bacteroides role in gut microbiota, it had no different distribution between healthy persons and CKD/ESRD patients.

The Association between Diet and Multiple Sclerosis.

BACKGROUND: Multiple sclerosis (MS) is a chronic autoimmune disease of the Central Nervous System (CNS) that affects individuals between the ages of 20 and 40 years, with a higher prevalence among women. Prevalence of this disease has increased significantly in recent decades in different geographical areas. There is evidence to suggest that both genetic and environmental factors play a role in the development of MS. OBJECTIVE: This study aims to investigate the potential relationship between diet and MS in the Azeri population of the East Azerbaijan province of Iran. METHODS: 467 MS patients and 260 non-related healthy individuals under the age of 15 completed a dietary demographic questionnaire. The relationship between food consumption and MS was evaluated using the obtained data. RESULTS: MS patients had a significantly higher consumption of fat, high-fat dairy, fast food, soybean, sausages and kielbasa, pickles, and leftover food (p-value=0.0001), while healthy individuals had a higher consumption of fruit (p-value=0.0001). Consumption of Meat, sweets, and fizzy drinks was also found to be higher in MS patients (p-value<0.05). There was no significant difference in the consumption of vegetables, cakes biscuits, and spices between the two groups (p-value>0.05). CONCLUSION: The results suggest that fruit consumption under the age of 15 may be a protective factoragainst MS, while the consumption of fat, high-fat dairy, fast food, soybean, sausages and kielbasa, pickles, leftover food, meat, sweets, sauce, and fizzy drinks under the age of 15, maybe risk factors for MS.