Access microbiology最新文献

{"title":"Tossing the coin of extended-spectrum β-lactamase: prevalence of extended-spectrum β-lactamase-producing Klebsiella pneumoniae isolated from patients with sepsis.","authors":"Beatrice Achan, Tonny Luggya, Robert Innocent Ebwongu, Simon Sekyanzi, Henry Kajumbula","doi":"10.1099/acmi.0.000962.v3","DOIUrl":"10.1099/acmi.0.000962.v3","url":null,"abstract":"<p><p><b>Background.</b> <i>Klebsiella pneumoniae</i> is part of the ESKAPE (<i>Enterococcus faecium</i>, <i>Staphylococcus aureus</i>, <i>K. pneumoniae</i>, <i>Acinetobacter baumannii</i>, <i>Pseudomonas aeruginosa</i> and <i>Enterobacter</i> spp.) group of multidrug-resistant (MDR) pathogens. <i>K. pneumoniae</i> is the leading cause of antimicrobial resistance-associated mortality and the second leading cause of nosocomial bloodstream infections (BSIs), globally and in sub-Saharan Africa. Therefore, it was aimed to determine the antibiotic resistance patterns of <i>K. pneumoniae</i> isolated from blood cultures of patients with features of sepsis at Mulago National Referral Hospital, Uganda. <b>Methods.</b> The cross-sectional study on patients with features of sepsis utilized <i>K. pneumoniae</i> (<i>n</i>=30) isolated from positive blood culture specimens. The antibiotic resistance profile was determined by the Clinical and Laboratory Standards Institute's Kirby-Bauer disc diffusion method, which was used to classify the isolates as susceptible, intermediate and resistant. <i>K. pneumoniae</i> isolates that were resistant to third-generation cephalosporins were subjected to extended-spectrum <i>β</i>-lactamase (ESBL) screening and confirmation using the double-disc synergy test using cefotaxime, ceftazidime, ceftriaxone, cefotaxime-clavulanic acid and ceftazidime-clavulanic acid. The results were analysed for frequencies. <b>Results.</b> <i>K. pneumoniae</i> isolates showed emerging resistance to imipenem at 13% (4 out of 30) followed by amikacin at 17% (5 out of 30). There was intermediate resistance to gentamycin at 60% (18 out of 30). However, <i>K. pneumoniae</i> showed the highest resistance to piperacillin at 100% (30 out of 30) followed by sulphamethoxazole-trimethoprim and cefepime, both showing a percentage of 97% (29 out of 30). Up to 16 out of 30 (53.3%) of <i>K. pneumoniae</i> were positive for ESBL production, whilst 14 out of 30 (46.7%) were negative. <b>Conclusion.</b> There was a high prevalence of antibiotic-resistant <i>ESBL</i>-producing <i>K. pneumoniae</i> isolates from BSI of patients with features of sepsis in Uganda's Mulago National Referral Hospital.</p>","PeriodicalId":94366,"journal":{"name":"Access microbiology","volume":"7 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11840160/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143470331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Immunogenicity of virus-like particle vaccine candidates against SARS-CoV-2 infection.","authors":"Hai Trong Nguyen, Ravendra Garg, Andrea Kroeker, Volker Gerdts, Darryl Falzarano, Qiang Liu","doi":"10.1099/acmi.0.000925.v3","DOIUrl":"10.1099/acmi.0.000925.v3","url":null,"abstract":"<p><p>Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to evolve, potentially leading to variants of concern that could become more transmissible, resist treatment, evade host immunity and reduce the effectiveness of currently available vaccines. Improved vaccines are still required as vaccination remains the most effective strategy against this virus. We have produced two SARS-CoV-2 virus-like particles (VLPs) using a baculovirus BacMam expression platform and examined their immunogenicity in mice. VLP1 contains the spike protein from the Wuhan strain, whereas VLP2 contains that of an Omicron variant. Mice immunized with VLP1 and boosted with VLP2 developed significantly higher antibodies in the sera, as well as higher numbers of IFN-γ secreting cells than the control group. Furthermore, both VLPs induced virus-neutralizing antibodies against Wuhan and Omicron variants. In conclusion, VLPs have the potential for the development of a safe and effective vaccine against SARS-CoV-2 variants.</p>","PeriodicalId":94366,"journal":{"name":"Access microbiology","volume":"7 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11833050/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143451404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The ratio between SARS-CoV-2 RNA viral load and culturable viral titre differs depending on the stage of infection: a case study of household transmission in an adult male.","authors":"Michael K Porter, Alexander Viloria Winnett, Linhui Hao, Natasha Shelby, Jessica A Reyes, Noah W Schlenker, Anne E Romano, Colton Tognazzini, Matthew Feaster, Ying-Ying Goh, Michael Gale, Rustem F Ismagilov","doi":"10.1099/acmi.0.000732.v3","DOIUrl":"10.1099/acmi.0.000732.v3","url":null,"abstract":"<p><p>Effective public health measures for communicable diseases rely on the ability to identify infectious individuals and prevent transmission from those individuals. For severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the presence of replication-competent virus in specimens from an individual is the gold standard for confirming infectiousness. However, viral culture from clinical specimens is difficult and infrequently performed. Instead, infectiousness may be inferred based on the abundance of viral RNA (or viral load) in a specimen, which is more easily assessed. For this reason, understanding the relationship between RNA viral load and infectious viral titre has important implications for public health strategy. In this case report, we quantified incident, longitudinal SARS-CoV-2 viral loads collected from saliva and nasal-swab specimens, and viral titre from nasal-swab specimens. We observed that the relationship between viral load and viral titre decreases by over five orders of magnitude throughout the course of the infection. Our work demonstrates the potential for infectious virus even in specimens with low viral loads collected during the early phases of infection.</p>","PeriodicalId":94366,"journal":{"name":"Access microbiology","volume":"7 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11833051/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143451405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantification of Pseudomonas aeruginosa biofilms using electrochemical methods.","authors":"Lily Riordan, Perrine Lasserre, Damion Corrigan, Katherine Duncan","doi":"10.1099/acmi.0.000906.v4","DOIUrl":"10.1099/acmi.0.000906.v4","url":null,"abstract":"<p><p>Currently, 2.29% of deaths worldwide are caused by antimicrobial resistance (AMR), compared to 1.16% from malaria and 1.55% from human immunodeficiency virus and acquired immunodeficiency syndrome. Furthermore, deaths resulting from AMR are projected to increase to more than 10 million <i>per annum</i> by 2050. Biofilms are common in hospital settings, such as medical implants, and pose a particular problem as they have shown resistance to antibiotics up to 1000-fold higher than planktonic cells because of dormant states and reduced growth rates. This is compounded by the fact that many antibiotics target mechanisms of active metabolism and are therefore less effective. The work presented here aimed to develop a method for biofilm quantification, which could be translated into the clinical setting, as well as used in the screening of antibiofilm agents. This was carried out alongside crystal violet staining, as a published point of reference. This work builds upon work previously presented by Dunphy <i>et al.</i>, in which the authors attempted to quantify the biofilm formation of <i>Pseudomonas aeruginosa</i> strain using hyperspectral imaging. Here, using electrochemical impedance spectroscopy and square wave voltammetry, the biofilm formation of two <i>P. aeruginosa</i> strains was detected within an hour after seeding <i>P. aeruginosa</i> on the sensor. A 40% decrease in impedance modulus was shown when <i>P. aeruginosa</i> biofilm had formed, compared to the media-only control. As such, this work offers a starting point for the development of real-time biofilm sensing technologies, which can be translated into implantable materials.</p>","PeriodicalId":94366,"journal":{"name":"Access microbiology","volume":"7 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11829079/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143434886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Whole-genome sequencing of the Streptomyces coelicolor bldA39 mutant (J1700) reveals hundreds of previously unknown mutations.","authors":"Jack W Stone, John T Munnoch, Paul A Hoskisson","doi":"10.1099/acmi.0.000958.v3","DOIUrl":"10.1099/acmi.0.000958.v3","url":null,"abstract":"<p><p>We report the genome sequence of the <i>bldA39</i> (J1700) mutant of <i>Streptomyces coelicolor</i>, a historically important strain that is deficient in sporulation and antimicrobial production. The <i>S. coelicolor</i> J1700 strain was used extensively from the 1980s onwards to underpin important discoveries in development and antibiotic production in <i>Streptomyces</i>. The <i>bldA</i> gene encodes a leucyl tRNA, required for the translation of the rare TTA codon found in ~2% of genes in <i>Streptomyces</i>. The whole genome of <i>S. coelicolor</i> J1700 was obtained via Illumina sequencing and mapped to the <i>S. coelicolor</i> M145 reference genome. Analysis of the genome sequence compared to <i>S. coelicolor</i> M145 identified the known <i>bldA39</i> mutation (T>C) and revealed more than 300 further mutations, likely associated with the <i>S. coelicolor</i> J1501 genetic background the strain was created in, including the nature of the <i>hisA1</i> and <i>uraA1</i> alleles used extensively in genetic mapping experiments and several mutations in natural product biosynthetic gene clusters. This work highlights the importance of whole-genome sequencing of historically important strains.</p>","PeriodicalId":94366,"journal":{"name":"Access microbiology","volume":"7 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11836424/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143461548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genome sequences of pathogenic and non-pathogenic Pantoea ananatis strains in maize (Zea mays L.).","authors":"Izabela Moura Duin, Viviane Yumi Baba, Katherine M D'Amico-Willman, Fernanda Neves Paduan, Vanessa Hitomi Sugahara Rodrigues, Jose C Huguet-Tapia, Jeffrey Bryant Jones, Marcelo G Canteri, Rui Pereira Leite Júnior, Maria Isabel Balbi-Peña","doi":"10.1099/acmi.0.000709.v3","DOIUrl":"10.1099/acmi.0.000709.v3","url":null,"abstract":"<p><p>We performed genome sequencing and comparative analysis of <i>Pantoea ananatis</i> strains isolated from corn leaves expressing typical bacterial leaf streak (BLS) and maize white spot (MWS) symptoms to confirm bacterial identity and to understand the relationship among these strains and <i>P. ananatis</i> strains isolated from different plant hosts in Brazil. In pathogenicity tests, strains 4.2 and 13.3 isolated from symptomatic BLS leaves were non-pathogenic on corn. In contrast, strain B13 isolated from MWS-diseased leaf tissue caused symptoms typical of MWS. Our comparative analysis revealed that all three strains are very genetically similar. The G+C (%) content of strains 4.2 and 13.3 was 53.5%, while the B13 content was 53.7%. Average nucleotide identity (ANI) analysis showed that strains B13 and 13.3, B13 and 4.2, and 4.2 and 13.3 shared ANIs of 99.17%, 99.15% and 99.99%, respectively. Strains 13.3, B13, and 4.2 shared ~99% ANI with <i>P. ananatis</i> type strain LMG 2665. To the best of our knowledge, these are the first genome sequences of <i>P. ananatis</i> strains isolated from corn in Brazil.</p>","PeriodicalId":94366,"journal":{"name":"Access microbiology","volume":"7 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11829076/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143434882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Campylobacter fetus subsp. fetus: an unforeseen cause of abortion in regional Australia.","authors":"Immanuella Owusu-Ansa, Manjeera Ramadas, Nikhitha Jacob, Femi E Ayeni","doi":"10.1099/acmi.0.000889.v5","DOIUrl":"10.1099/acmi.0.000889.v5","url":null,"abstract":"<p><p><i>Campylobacter fetus (C. fetus)</i> subsp. <i>fetus,</i> a Gram-negative bacterium, is an established cause of abortion and infertility in cattle, sheep and goats. Human infections have been rarely reported. In contrast to TORCH infections, this <i>Campylobacter</i> species is hardly recognized as a cause of abortion in humans. Since 1947 after the first case report in France, there have been only 11 reported cases of pregnant women worldwide and no published reports in Australia, pregnant or otherwise. The case in this study was compared to the first reported infection of <i>C. fetus</i> in 1947 to raise awareness and educate doctors and midwives, subsequently impacting prenatal and antenatal counselling in these regions. A Venn diagram was constructed to highlight the similarities between this and the index case. The similarities found included the clinical state of the patient post-abortion and the all-important history of exposure to farm animals that suffered recent deaths on the farms of both patients. Some of the differences included the time of onset of symptoms to the time of abortion, the choice of antibiotics by both treating teams and the presentation of sepsis, suggesting the importance of <i>C. fetus</i> subsp. <i>fetus</i> as a perinatal infection.</p>","PeriodicalId":94366,"journal":{"name":"Access microbiology","volume":"7 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11829075/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143434879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of the virulence of community- and hospital- isolated Acinetobacter baumannii in HeLa cell line and insect model, Galleria mellonella.","authors":"Nazmul Hasan Muzahid, Aarthi Ramesh, Tan Hock Siew, Md Zobaer Hasan, Kumaran Narayanan, Sadequr Rahman","doi":"10.1099/acmi.0.000858.v3","DOIUrl":"10.1099/acmi.0.000858.v3","url":null,"abstract":"<p><p><i>Acinetobacter baumannii</i> is an important nosocomial pathogen causing high infections and morbidity among affected individuals, and most studies focus on nosocomial strains. However, <i>A. baumannii</i> can also be isolated from healthy community individuals. This study compared the pathogenicity of hospital and community <i>A. baumannii</i> isolates using <i>Galleria mellonella</i> and human cell cultures. The insect model, <i>G. mellonella</i>, and <i>in vitro</i> HeLa cell line were used with ten <i>A. baumannii</i> isolates (six community and four hospital isolates from Segamat, Malaysia). <i>G. mellonella</i> killing assays and HeLa cell adherence, invasion and cytotoxicity assays were performed to investigate the virulence and invasion potential of the isolates. Out of the ten isolates investigated, three community and two hospital isolates were found to be highly virulent in the <i>G. mellonella</i> infection model, killing 100% of larvae within 96 h. These strains were also found to be invasive and have significant cytotoxicity in HeLa cells. Our study revealed that community- and hospital-isolated <i>A. baumannii</i> could be equally virulent judged by both model systems. Undoubtedly, besides hospital settings, the presence of highly virulent <i>A. baumannii</i> in community reservoirs poses a significant public health risk and requires additional investigation.</p>","PeriodicalId":94366,"journal":{"name":"Access microbiology","volume":"7 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11829074/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143434881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-quality PacBio draft genome sequences of 17 free-living Bradyrhizobium and four related Nitrobacteraceae strains isolated from arid soils in the Santa Catalina Mountains of Southern Arizona.","authors":"Melanie R Kridler, Amanda Howe, Jimaree A Legins, Christina Guerrero, Ryan P Bartelme, Bridget Taylor, Paul Carini","doi":"10.1099/acmi.0.000884.v3","DOIUrl":"10.1099/acmi.0.000884.v3","url":null,"abstract":"<p><p>Non-symbiotic <i>Bradyrhizobium</i> are among the most abundant and ubiquitous microbes in bulk soils globally. Despite this, most available genomic resources for <i>Bradyrhizobium</i> are derived from plant-associated strains. We present high-quality draft genomes for 17 <i>Bradyrhizobium</i> and four <i>Nitrobacteraceae</i> cultures isolated from bulk semiarid soils in Arizona, USA. The genome sizes range from 5.99 to 10.4 Mbp. Phylogenomic analysis of the 21 genomes indicates they fall into four clades. Two of the clades are nested within the <i>Bradyrhizobium</i> genus. The other two clades were associated with <i>Nitrobacteraceae</i> outgroups basal to <i>Bradyrhizobium</i>. All genomes lack genes coding for molybdenum or vanadium nitrogenases, and <i>nod</i> genes that code for proteins involved in nodulation, suggesting these isolates are free-living, non-symbiotic and do not fix dinitrogen gas. These genomes offer new resources for investigating free-living <i>Bradyrhizobium</i> lineages.</p>","PeriodicalId":94366,"journal":{"name":"Access microbiology","volume":"7 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11825986/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143434884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Beyond lectures: leveraging competition, peer discussion and real-world scenarios in a digital card game to enhance learning of microbiology and immunology concepts.","authors":"Michael J Dillon, James Edwards, Alexandra Hughes, Holly N Stephenson","doi":"10.1099/acmi.0.000900.v3","DOIUrl":"10.1099/acmi.0.000900.v3","url":null,"abstract":"<p><p>Teaching the complex interactions between hosts and pathogens is a fundamental yet educationally challenging aspect of life science and healthcare education. The intricate mechanisms of the immune system can pose significant barriers to students' understanding of infectious disease diagnosis and treatment. To address this, we used a web-based digital whiteboard platform to design a card-based competitive game called Micro-Immune Battles, aimed at more actively engaging students with microbiology and immunology to better develop their knowledge and underlying concepts. The game facilitates learning through a series of infectious disease scenarios, providing student teams with 'immune system response cards' that represent various immune elements. Working in teams, learners must construct sequential card cascades that correctly correspond to the specified pathogen in the scenario. This reinforces the temporal progression of immune responses whilst encouraging the application of theoretical knowledge to practical cases. Scoring is determined by the accuracy and speed of card placements, incentivizing rapid yet correct synthesis of knowledge. Points are deducted for incorrect placements, introducing an element of calculated risk-taking and critical reasoning. Analysis showed statistically significant improvements in microbiology and immunology knowledge after playing the game.</p>","PeriodicalId":94366,"journal":{"name":"Access microbiology","volume":"7 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11825987/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143434877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}