GNAT toxin may have a potential role in Pseudomonas aeruginosa persistence: an in vitro and in silico study.

Aims: Persistent cells are primarily responsible for developing antibiotic resistance and the recurrence of Pseudomonas aeruginosa. This study investigated the possible role of GNAT toxin in persistence. Materials & methods: P. aeruginosa was exposed to five MIC concentrations of ciprofloxacin. The expression levels of target genes were assessed. The GNAT/HTH system was bioinformatically studied, and an inhibitory peptide was designed to disrupt this system. Results: Ciprofloxacin can induce bacterial persistence. There was a significant increase in the expression of the GNAT toxin during the persistence state. A structural study of the GNAT/HTH system determined that an inhibitory peptide could be designed to block this system effectively. Conclusion: The GNAT/HTH system shows promise as a novel therapeutic target for combating P. aeruginosa infections.

Antibiotics are used to treat infections caused by bacteria. Over time, some of these infections have become more difficult to treat. This is because the bacteria can slow their growth and tolerate the antibiotic, known as persistence. It is important to find new ways to treat infections caused by persistent bacteria. This study researched a toxin­antitoxin system, called GNAT/HTH, that may play a role in bacterial persistence. This system could be a target for new antibiotics.

In Vitro and In Silico Investigation of some Type II TA Genes in H. Pylori.

BACKGROUND: In addition to antibiotic resistance, the entry of Helicobacter pylori into the persistence phase leads to recurrent and chronic infections, as well as the development of antibiotic resistance in persister cells. METHODS: In this study, after genetic confirmation of H. pylori in 20 biopsy specimens, the prevalence of the type II TA systems mazEF, relEB, yafQ/dinJ was investigated. Also, the most common system observed in the study in terms of structure, evolution, and molecular interaction was evaluated by bioinformatics tools. RESULTS: The results of the PCR test on 20 biopsy samples were positive for ureA and glmM genes. Moreover, yafQ/ dinJ was the only module positive in half of the samples (10 samples) in the PCR technique. The toxin residues and their interactions with the cognate antitoxin residues are revealed by docking analysis results. Furthermore, the multiple sequence alignment (MSA) of the YafQ toxin showed that this toxin has a low polymorphism among H. pylori species. The evolutionary study showed that the yafQ toxin had the highest sequence similarity among the bacteria Helicobacter cetorm (60% similarity) and Muricauda olearia (57.35 % similarity). CONCLUSIONS: Collectively, the data of the present study indicate that the YafQ/DinJ is the dominant type II TA system and has the highest frequency among the studied systems in H. pylori, and further studies are required to elucidate its exact role in this bacterium.

Economic evaluation of laboratory diagnostic test types in Covid-19 epidemic: A systematic review.

BACKGROUND: Corona 2 virus (SARS-CoV-2) is known as the causative agent of COVID-19 disease; the World Health Organization (WHO) declared it an epidemic on March 11, 2020. The Joint Guidelines of the Centers for Disease Control and Prevention (CDC) and the WHO including social distancing, the use of face masks, emphasis on hand washing, quarantine, and using diagnosis tests have been used widely, but the value of diagnostic interventions to prevent the transmission of SARS-CoV-2 is unclear. We compared the economic evaluation of different laboratory diagnostic interventions with each other and also with implementing the conservative CDC & WHO guidelines. MATERIAL AND METHODS: Electronic searches were conducted on PubMed, Embase, Science Direct, Scopus, Cochrane Library, Web of Knowledge, NHSEED, NHS Health Technology assessment (CRD), and Cost-Effectiveness Analysis Registry databases. Related articles were reviewed from January 2020 to the end of November 2021. RESULTS: Out of 1791 initial studies, 13 articles had the inclusion criteria. According to the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist, ten studies were of excellent quality, and the remaining two studies were of very good quality. Most studies were cost-effectiveness analysis studies. The entered studies had different time horizons. Diagnostic tests reviewed in the studies included real-time polymerase chain reaction (RT-PCR) test, immunoglobulin G (IgG) & Antigen, point of care tests. Although polymerase chain reaction (PCR) testing improves the quality of life and survival for patients with infected Covid-19 based on its greater effectiveness compared to standard protection protocols, due to the high cost of this intervention, it has been considered a cost-effective method in some countries. CONCLUSION: Since most studies have been conducted in developed countries, it unquestionably does not make sense to extend these results to low-income and developing countries. Therefore further studies are required in low-income and developing countries to evaluate the cost-effectiveness of laboratory-based diagnostic methods (RT-PCR) of covid-19 in variable prevalence of infectious cases.

Heteroresistance to clarithromycin and metronidazole in patients with a Helicobacter pylori infection: a systematic review and meta-analysis.

BACKGROUND: Antimicrobial resistance of H. pylori can lead to treatment failure. Importantly, several studies have reported on heteroresistance, i.e. the presence of resistant and susceptible H. pylori populations in the same sample and/or a difference in the susceptibility patterns between biopsy samples. This meta-analysis aims to provide comprehensive data on the prevalence of metronidazole and clarithromycin heteroresistance and the approaches to their detection. MATERIAL AND METHODS: A systematic review was performed after the search of MEDLINE, Scopus and Web of Science. The study outcomes were the weighted pooled prevalence of heteroresistance to clarithromycin and metronidazole in H. pylori positive samples and/or isolates with a subanalysis by continent. RESULTS: A total of 22 studies that had investigated 3852 H. pylori positive patients were included in the meta-analysis. Heteroresistance to clarithromycin was reported in 20 studies, with a weighted pooled prevalence of 6.8% (95% CI 5.1-8.6; 3654 H. pylori positive patients; the substantial heterogeneity I2 = 55.6%). Heteroresistance to metronidazole was reported in 12 studies, with a weighted pooled prevalence of 13.8% (95% CI 8.9-18.6; 1670 H. pylori positive patients; the substantial heterogeneity I2 = 60.9%). The weighted pooled prevalence of clarithromycin heteroresistance was similar in Asia and Europe (p = 0.174584), however, metronidazole heteroresistance was detected more often in Europe (p < 0.00001). Clarithromycin heteroresistance was detected more often by phenotype rather than by using genotyping methods (12 vs 8 studies), whereas heteroresistance to metronidazole was detected only by phenotype. CONCLUSION: The prevalence of heteroresistance to clarithromycin and/or metronidazole is not negligible and can be detected in approximately 7 and 14% of H. pylori positive samples, respectively. These findings highlight the need to raise the awareness of gastroenterologists and microbiologists to the heteroresistance to clarithromycin and metronidazole in patients with a H. pylori infection.

Persister cells as a possible cause of antibiotic therapy failure in Helicobacter pylori.

BACKGROUND AND AIM: Due to the failure of antibiotic treatment and recurrence of infection in patients with Helicobacter pylori, this study was designed to find the possible cause of treatment failure and recurrence of the H. pylori infections in Ilam, Iran. METHODS: One hundred patients with specific symptoms of H. pylori infection were selected, and after taking a biopsy specimen, identification of H. pylori, antibiotic susceptibility assay, and persister cell assay were performed. In addition, after treatment, patients with persister cells were followed for possible recurrence of infection. Furthermore, an antibiotic susceptibility assay was performed. RESULTS: Our results demonstrated that, among 100 patients, 50% (n = 50) showed positive results for the existence of H. pylori. Among the susceptible isolates, 18% (n = 9) were persister cells that were sensitive to clarithromycin as confirmed by a 5 folds higher than the Minimal Inhibitory Concentration (MIC) of clarithromycin. The data were confirmed by following up the suspected patients. CONCLUSION: Our results demonstrated that persister cells in H. pylori infections may be responsible to recurrent infection and antibiotic treatment failure. However, more research is needed to obtain more information in this area.

Anticancer properties of colicin E7 against colon cancer.

INTRODUCTION: Cancer is a major public health problem in the modern world. Every year, new cases of cancer are diagnosed around the world. Cancer cells are altered cells that have escaped the mechanisms that regulate natural growth. Bacteriocins are cationic peptides synthesized by ribosomes that are secreted by almost all groups of bacteria. Some bacteriocins have shown selective toxicity to cancer cells compared to normal cells. This makes them other candidates for research and clinical trials. AIM: Due to the high prevalence of colon cancer and its therapeutic problems, this study was performed on colicin E7 to evaluate its anti-colon cancer properties. MATERIAL AND METHODS: For this reason, colE7 was cloned in pet32c vector and purified protein was affected on HT-29 cells to evaluate the expression of p53 and bcl2. RESULTS: Our in silco analysis demonstrated that colicin E7 has 87.23% confidence as anticancer peptide by ACPred-FL program. First, a PCR reaction was performed using specific primers of the colicin E7 gene, which formed the 1728 bp fragment that belongs to this gene. CONCLUSIONS: Colicin E7 decreased the expression of bcl2 and increased P53. The results of this study showed the general effect of colicin E7 on cancer cells in vitro, which can be evaluated in the future with further experiments.

Ethanolic Extract of Berberis Vulgaris Fruits Inhibits the Proliferation of MCF-7 Breast Cancer Cell Line Through Induction of Apoptosis

BACKGROUND: As it is obvious, there is much documentation that shows the importance of breast cancer treatment in patients. High expressions of P53 and Bcl-2 are associated with breast cancer, which are reliable factors to follow up the breast cancer. Berberis vulgaris is used as a traditional medicine in cancer. Despite of the fact that many researches have demonstrated its anti-cancer properties, there are no scientific documents to show its efficacy in detail in breast cancer. OBJECTIVE: Because of traditional use of B. vulgaris and little knowledge about its effects, our research was focused on determining the efficacy and toxicity of B. vulgaris. For this reason, we determined the efficacy of B. vulgaris on breast cancer cells. METHOD: As described in Method section, standard protocols including MTT assay and qPCR were performed to identify the effect of B. vulgaris ethanolic extract against breast cancer cells. RESULTS: Our results clearly demonstrated that 35 mg/ml had IC50 against 3t3 normal cells, and 9 mg/ml of B. vulgaris was effective against MCF-7 breast cancer cells. The results demonstrated that even at only 1 mg/ml concentration of B. vulgaris, crude extract was effective, 9 mg/ml and 12 mg/ml of extract had better anti-cancer activity compared with doxorubicin. CONCLUSION: Despite that the role of anticancer properties of B. vulgaris was clearly defined in some patents, our results demonstrated the potency of B. vulgaris against breast cancer, but further analysis should be performed to candidate this herb as an anti-breast cancer drug.

Novel Information about Neisseria meningitidis: Identification of the Most Important Type II Toxin Antitoxin Systems.

BACKGROUND: Toxin antitoxin systems is the one of the important elements among pathogenic bacteria which have proven roles such as biofilm formation, cell programmed death and persister cells formation. Neisseria meningitidis causing serious diseases in humans must be highlighted. OBJECTIVE: The current study aimed to identify the mazEF and relBE TA systems in N. meningitidis. METHOD: The potential TA loci were searched in RASTA database by bioinformatics analysis and then, experimental analysis was performed by PCR assay. PCR products were confirmed by sequencing. RESULTS: Our findings demonstrated that mazEF and relBE TA systems were positive by PCR assay and results of sequencing confirmed the PCR results. CONCLUSION: Notably, our highlighted findings are the first report of mazEF and RelBE TA loci in N. meningitides. Finally, we strongly recommended that laboratory experiments should be performed to identify the roles of these TA loci in N. meningitides.

Antibacterial, anti-swarming and anti-biofilm formation activities of Chamaemelum nobile against Pseudomonas aeruginosa

Chamomile ( Chamaemelum nobile ) is widely used throughout the world, and has anti-inflammatory, deodorant, bacteriostatic, antimicrobial, carminative, sedative, antiseptic, anti-catarrhal, and spasmolytic properties. Because of the increasing incidence of drug-resistant bacteria, the development of natural antibacterial sources such as medical herbs for the treatment of infectious diseases is necessary. Extracts from different plant parts such as the leaves, flowers, fruit, and bark of Combretum albiflorum, Laurus nobilis , and Sonchus oleraceus were found to possess anti-quorum sensing (QS) activities. In this study, we evaluated the effect of C. nobile against Pseudomonas aeruginosa biofilm formation

The mazEF toxin-antitoxin system as a novel antibacterial target in Acinetobacter baumannii

Although analysis of toxin-antitoxin (TA) systems can be instructive, to date, there is no information on the prevalence and identity of TA systems based on a large panel of Acinetobacter baumannii clinical isolates. The aim of the current study was to screen for functional TA systems among clinical isolates of A. baumannii and to identify the systems’ locations. For this purpose, we screened 85 A. baumannii isolates collected from different clinical sources for the presence of the mazEF, relBE and higBA TA genes. The results revealed that the genes coding for the mazEF TA system were commonly present in all clinical isolates of A. baumannii. Reverse transcriptase-polymerase chain reaction analysis showed that transcripts were produced in the clinical isolates. Our findings showed that TA genes are prevalent, harboured by chromosomes and transcribed within A. baumannii. Hence, activation of the toxin proteins in the mazEF TA system should be investigated further as an effective antibacterial strategy against this bacterium.

Synthesis and evaluation of monoclonal antibody against Plasmodium falciparum merozoite surface antigen 2.

OBJECTIVE: To assess the quality of expressed MSP-2 and also to confirm the immune response against different domains of these proteins. METHODS: Mice were immunized with a schizont extract to stimulate the immune system to make antibodies against different antigens of the late stage parasite including production of antibodies against different domains of Plasmodium falciparum (P. falciparum) MSP-2. B lymphocytes of immunized mice were extracted from the spleen and the fusion was performed using NS-1 myeloma cells and the hybridoma cells were assayed by ELISA either with a schizont extract or different domains of MSP-2 and/or by IFAT with whole schizont preparation. Fusion of NS-1 and spleen cells was performed. The positive hybrids were cloned and ELISA was applied against different dilutions. The positive clones were transferred to a small tissue culture flask and after developing they were assayed against schizont extract and the different MSP-2 domains. The positive clones were expanded to large (75 cm(2)) flask and cultured under the same conditions, checking them using both ELISA and IFAT and the positive cells were frozen as soon as possible. RESULTS: A total number of 7 fusions including 26 plates (2 496 wells) were performed, of which 1 336 hybrids were produced and the overall efficiency (1 336/2496 × 100) was about 53%. ELISA was performed to detect the positive hybrids against crude schizont extract by which the highest frequency to crude schizont extract was found for the supernatant of the hybrids produced in fusion number 3 (66 out of 315 hybrids). The supernatant of both B5 and F1 hybridoma cells were more positive against domain 2 of the MSP-2 recombinant protein in Western blotting test. Western blotting results also showed that different domains of the MSP-2 recombinant protein and also the MSP-2 of the P. falciparum parasite were recognized by some of the positive clones and also immune sera. CONCLUSIONS: Bringing together all the results of this study it has been confirmed that some clones have recognized both schizont extract and different domains of the MSP-2 recombinant protein and therefore confirming the quality of the MSP-2 domains.

Cross-Reaction between the Crude Hydatid Cyst Fluid Antigens of Human and Animals Origin in Response to Human IgG Class and Subclasses.

The current work aimed to evaluate the cross-reactivity of human immune sera against crude hydatid fluid antigens of sheep, human, mouse, cattle, as well as B fraction of cystic fluid antigen. 30 balb/c mice were infected with sheep hydatid cyct fluid antigen containing protoscolex after the viability of these protoscolices was assessed. ANOVA was used to test the difference of themean of optical density (OD) values among case and control groups. The highest human IgG class antibody was against antigen B (0.93) and the lowest against cattle HCF antigen (0.32). The differences between responses to these antigens were statistically significant (P < 0.001). The sensitivity and specificity of ELISA test used for evaluating the responses of human total IgG to different hydatid cyst fluid (HCF) antigens among the case and control groups were 100 and 95.8%, respectively. Cross-reaction of human IgG class and subclasses responses was found almost for all the antigens with the best reaction against human and cattle (HCF) antigens and antigen B using a ratio of mean OD value to each antigen divided by the cut-off point value for the same antigen. Human sera showed a considerable cross-reactivity against all antigens by using ELISA.

Incidence of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in patients with urinary tract infection / Incidência de Klebsiella pneumoniae produtoras de beta-lactamases de espectro estendido em pacientes com infecção do trato urinário

CONTEXT AND OBJECTIVES: Resistant bacteria are emerging worldwide as a threat to favorable outcomes from treating common infections in community and hospital settings. The present investigation was carried out to study the incidence of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae in patients with urinary tract infection in different seasons of the year, in order to determine the prevalence of the genes blaTEM, blaSHV and blaCTX-M, which are responsible for ESBL production among ESBL-producing K. pneumoniae, in three cities in Iran, and to investigate the antimicrobial susceptibility pattern of K. pneumoniae in different seasons. DESIGN AND SETTING: Retrospective study carried out among patients with urinary tract infections in five hospitals in Iran. METHOD: Two hundred and eighty-eight clinical isolates of K. pneumoniae were collected between March 2007 and April 2008 from five hospitals in three cities in Iran. ESBLs were identified by phenotypic and genotypic methods. ESBL-producing Klebsiella pneumoniae were evaluated against non-beta-lactam antibiotics. Genes coding for ESBLs (blaSHV, TEM and CTX-M) were screened. RESULTS: Among the 288 clinical isolates of K. pneumoniae, 37.7 percent, 46.7 percent and 15.6 percent were obtained from hospitals in Ilam, Tehran and Tabriz, respectively, of which 39.4 percent, 50.7 percent and 45.8 percent were ESBL-producing K. pneumoniae in Ilam, Milad and Emam Reza hospitals, respectively. CONCLUSION: According to the results from this study, resistance to third-generation cephalosporins is higher during the cold months than during the warm months.

CONTEXTO E OBJETIVOS: As bactérias resistentes estão surgindo em todo o mundo como uma ameaça ao resultado favorável no tratamento de infecções comuns em ambientes comunitários e hospitalares. O presente estudo foi realizado com o objetivo de avaliar a incidência de Klebsiella pneumoniae produtoras de beta-lactamases de espectro estendido (BLEEs) em pacientes com infecção do trato urinário em diferentes estações do ano, para verificar a prevalência dos genes blaTEM, blaSHV e blaCTX-M responsáveis para a produção de BLEEs em K. pneumoniae productoras de BLEEs, em três cidades do Irã, e investigar o perfil de sensibilidade antimicrobiana de K. pneumoniae em diferentes estações. DESENHO E LOCAL: Estudo retrospectivo realizado em pacientes com infecções do trato urinário em cinco hospitais no Irã. MÉTODO: Duzentos e oitenta e oito isolados clínicos de K. penumoniae foram coletados entre março de 2007 e abril de 2008 em cinco hospitais de três cidades no Irã. BLEEs foram identificados por métodos fenotípicos e genotípicos. K. pneumoniae produtoras de BLEEs foram avaliadas contra antibióticos não beta-lactâmicos. Os genes codificadores de BLEEs (blaSHV, TEM e CTX-M) foram investigados. RESULTADOS: Entre os 288 isolados clínicos de K. pneumoniae, 37,7 por cento, 46,7 por cento e 15,6 por cento eram provenientes dos hospitais em Ilam, Tehran e Tabriz, respectivamente, dos quais 39,4 por cento, 50,7 por cento e 45,8 por cento eram K. pneumoniae produtoras de BLEEs nos hospitais em Ilam, Milad e Eman Reza, respectivamente. CONCLUSÃO: De acordo com os resultados deste estudo, a resistência às cefalosporinas de terceira geração é maior nos meses frios do que nos meses quentes.