Applied microbiology最新文献

{"title":"Thermal Inactivation of the Heat-Resistant Pathogens Salmonella Senftenberg 775W and Escherichia coli AW1.7 in Whey Concentrate","authors":"Gregor Fiedler, Stefan Nöbel, S. Matzen, M. Samtlebe, Charles M. A. P. Franz","doi":"10.3390/applmicrobiol4010036","DOIUrl":"https://doi.org/10.3390/applmicrobiol4010036","url":null,"abstract":"Pasteurized whey concentrate is used as a base for the production of ingredients for various food products. Whey concentrate (30% dry matter) was used to assess the thermal inactivation of Salmonella (S.) enterica serovar Senftenberg 775W (DSM 10062) and Escherichia (E.) coli AW1.7 (DSM 108612) strains in a pilot-scale pasteurizer mimicking industrial heat processing. These strains, chosen for their exceptional heat resistance, represent the most challenging scenario for pasteurization within the context of S. enterica and E. coli. Heat resistance was tested at temperatures of 56, 60, 64, 68, and 72 °C at an average holding time of 17.5 s. These exceptionally heat-resistant strains showed a relatively low reduction in numbers of between 0 and 4.2 log10 CFU/mL at lower inactivation temperatures of ≤68 °C. A reduction of at least 5 log10 CFU/mL, as required for adequate heat processing, was achieved for both species after heating at 72 °C for 17.5 s. This study shows that whey concentrate should not lead to contamination of food ingredients and can be considered safe after pasteurization at 72 °C for at least 17.5 s with respect to the pathogens tested.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"117 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140237746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Tale of Staphylococcus aureus Isolated from Mastitis Infections: The Effect of Antimicrobials and Bacterial Relatedness","authors":"Angela Perdomo, Maria Salazar, R. Janardhanan, Alexandra Calle","doi":"10.3390/applmicrobiol4010035","DOIUrl":"https://doi.org/10.3390/applmicrobiol4010035","url":null,"abstract":"Staphylococcus aureus is a common causative agent of mastitis in dairy cattle, posing a substantial threat to animal health and resulting in significant economic losses. Preventive measures are usually in place to control the spread of the organism between animals and around the dairy environment; however, mastitis outbreaks can still be recurrent. During this investigation, a total of 30 S. aureus isolates were obtained from six deceased cows, all diagnosed with chronic mastitis during an outbreak in West Texas. The aim of this study was to evaluate the response of the S. aureus isolates causing severe mastitis infections to iodine treatments and their antibiotic susceptibility, planktonic growth, and biofilm formation. Udder skin was inoculated with S. aureus and subjected to various iodine concentrations of 0.25%, 0.38%, 0.50%, 0.75%, and 1.00%, with exposure times of 15 s, 10 s, and 60 s. The same concentrations were tested on S. aureus’s biofilm formation. The results of the antimicrobial susceptibility test indicate that the exposure time did not influence the treatment. Lower iodine concentrations were compared with 1.00%, as the standard treatment used by the dairy for teat disinfection, and statistical difference (p < 0.001) was evident in the 0.00% iodine treatment compared to the other iodine concentrations. Moreover, a significant difference (p < 0.001) emerged when comparing the 0.25% and 0.38% iodine concentrations with 1.00%. No difference (p > 0.161) was detected between 0.50%, 0.75%, and 1.00%. These results suggest that, under the conditions investigated, iodine can be lowered to around 50% of the currently used dose without negatively impacting microbial control. On the other hand, S. aureus strains were susceptible to the tested antibiotics, demonstrating that antimicrobial resistance does not always play a role in the persistent mastitis infections caused by S. aureus. Further microbial phenotypic typing conducted on S. aureus strains indicated a possible common source of the infections, demonstrating the potential of there being resident S. aureus strains at this dairy farm.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"256 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140255576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of the Antibacterial Activity of Isatin against Campylobacter jejuni and Campylobacter coli Strains","authors":"Claudia B. Barroso, Liliane M. Seki, Wagner T. C. Esteves, Michele C. Nascimento, Aurea Echevarria","doi":"10.3390/applmicrobiol4010034","DOIUrl":"https://doi.org/10.3390/applmicrobiol4010034","url":null,"abstract":"Antibiotic resistance, particularly against fluoroquinolones and macrolides, has emerged globally among thermophilic Campylobacters (Campylobacter jejuni and Campylobacter coli), giving rise to concerns about the efficacy of antibiotic treatment of these bacteria. Thus, developing new antibacterials with excellent activity is important. Isatin (IST) and its derivatives have exhibited promising antibacterial activities in several pathogenic bacteria. However, its activity against Campylobacter is unknown. Therefore, this study was conducted to evaluate the antibacterial activity of isatin against 29-Campylobacter strains (C. jejuni-17 and C. coli-12) and investigate the effects at the cellular level. The minimal inhibitory concentrations (MICs) of isatin were between <1.0 and 16.0 µg/mL in Campylobacter strains. Most strains presented with MIC = 8.0 µg/mL (76%). The minimal bactericidal concentration (MBC) was determined to be 16.0 µg/mL for 72% of the Campylobacter strains tested. The 50% inhibitory concentration (IC50) value for isatin was 125.63 µg/mL on the MRC-5 normal cell line, suggesting that isatin can be considered a safe substance in terms of cytotoxicity. In this study, we demonstrated the potential of isatin based on its low toxicity and effectiveness in vitro against antibiotic-resistant Campylobacter strains, which indicates that this compound could be an attractive candidate for future use in multidrug-resistant Campylobacter treatment.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140257951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surveillance of Bacterial Meningitis in the Italian Hospital of Desio: A Twenty-Year Retrospective Study","authors":"J. Intra, D. Carcione, Roberta Maria Sala, Claudia Siracusa, Paolo Brambilla, V. Leoni","doi":"10.3390/applmicrobiol4010033","DOIUrl":"https://doi.org/10.3390/applmicrobiol4010033","url":null,"abstract":"Bacterial meningitis is a severe infection with a high fatality rate, and affects children in particular. Three vaccines against the most common bacterial causatives of meningitis, Haemophilus influenzae type b, Streptococcus pneumoniae, and Neisseria meningitides, exist. Monitoring the type and incidence of bacterial meningitis is important for making future prevention and control plans. In this study, we retrospectively analyzed data regarding bacterial meningitis recovered in the Italian Hospital of Desio from 2000 to 2019. Samples from a total of 128 patients were included. Streptococcus pneumoniae was the most common microorganism, isolated in 45 cases, followed by Neisseria meningitidis (14), Listeria monocytogenes (8), Streptococcus agalactiae (group B) (4), and Haemophilus influenzae type b (2). The implementation of vaccination schedules decreased the number of bacterial meningitis cases caused by H. influenzae type b, S. pneumoniae, and N. meningitidis. Considering the bacterial meningitis cases in subjects aged 0–12 years, no H. influenzae type b strain was isolated, five cases of N. meningitidis were identified before the introduction of vaccination, and seven S. pneumoniae strains were isolated before the introduction of the PCV13 vaccination. Surveillance studies allowed us to monitor changes in bacteria distribution and to guide vaccination strategies.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"53 S1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140264834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Complementation of an Escherichia coli K-12 Mutant Strain Deficient in KDO Synthesis by Forming D-Arabinose 5-Phosphate from Glycolaldehyde with Fructose 6-Phosphate Aldolase (FSA)","authors":"Emma Guitart Font, G. Sprenger","doi":"10.3390/applmicrobiol4010032","DOIUrl":"https://doi.org/10.3390/applmicrobiol4010032","url":null,"abstract":"KDO (2-keto-3-deoxy-D-manno-octulosonate) is a landmark molecule of the Gram-negative outer membrane. Mutants without KDO formation are known to be barely viable. Arabinose 5-phosphate (A5P) is a precursor of KDO biosynthesis and is normally derived from ribulose 5-phosphate by A5P isomerases, encoded by kdsD and gutQ genes in E. coli K-12. We created a kdsD gutQ-deficient double mutant of strain BW25113 and confirmed that these cells are A5P auxotrophs. Fructose 6-phosphate aldolase (FSA) is known to utilize (among other donors such as dihydroxyacetone or hydroxyacetone) glycolaldehyde (GoA) as a donor compound and to provide A5P in vitro when glyceraldehyde 3-phosphate is the acceptor. We show here that this FSA function in vivo fully reverses the growth defect and the A5P deficiency in kdsD gutQ double mutants. Expression of both plasmid-encoded fsaA, fsaAA129S, or fsaB genes as well as a chromosomally integrated form of fsaAA129S led to maximal OD600 values of >2.2 when GoA was added exogenously (together with glucose as a C source) at a concentration of 100 µM (Ks values in the range of 4–10 µM). Thus, a novel bio-orthogonal bypass to overcome an A5P deficiency was opened. Lower GoA concentrations led to lower growth yields. Interestingly, mutant strains with recombinant fsa genes showed considerable growth yields even without exogenous GoA addition, pointing to yet unknown endogenous GoA sources in E. coli metabolism. This is a further example of the usefulness of FSA in rewiring central metabolic pathways in E. coli.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"4 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140081237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transcriptional Response of Salmonella enterica to Bacteriophage Treatments with Differential Multiplicities of Infection","authors":"Catherine W. Y. Wong, Siyun Wang","doi":"10.3390/applmicrobiol4010027","DOIUrl":"https://doi.org/10.3390/applmicrobiol4010027","url":null,"abstract":"Salmonella enterica (S. enterica) is a causative agent of numerous foodborne outbreaks, as current industrial measures may be <90% effective. Therefore, bacteriophages have been suggested as an antimicrobial treatment against S. enterica, but it is currently unclear if there is an optimal bacteriophage multiplicity of infection (MOI) against S. enterica. Two bacteriophage cocktails at MOIs 1, 10, 100, 1000 and 10,000 were co-inoculated against four S. enterica strains (S. Enteritidis, S. Newport, S. Muenchen and S. Typhimurium), and populations were estimated on days 0–3. The transcriptional profiles of 20 genes previously indicated to be differentially expressed after bacteriophage treatment were studied by extracting RNA from all four S. enterica strains after bacteriophage SE14, SF5 and SF6 treatment on days 0, 1 and 3, and RT-qPCR was conducted to determine the expression of the 20 selected genes. The results showed that an MOI of 1000 was the most optimal in reducing S. Enteritidis populations to undetectable levels from day 0 to 3. The cas1 (SOS response) and mod (DNA modification and recombination) genes were highly upregulated between 2.5- and 5-fold on day 0 for S. Enteritidis S5-483 and S. Typhimurium S5-536 at MOIs of 1000 and 10,000. On day 3, hsdS (DNA modification and recombination) was upregulated by ~1-fold for S. enteritidis S5-483 after an MOI of 1000. Understanding an optimal bacteriophage MOI can be beneficial to implementing effective and optimal bacteriophage treatments in the industry. Knowledge of S. enterica’s transcriptional response after bacteriophage treatment provides further insight into how S. enterica can survive bacteriophage infection.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"11 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139961042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combination Screening of a Naïve Antibody Library Using E. coli Display and Single-Step Colony Assay","authors":"Mieko Kato, Y. Hanyu","doi":"10.3390/applmicrobiol4010016","DOIUrl":"https://doi.org/10.3390/applmicrobiol4010016","url":null,"abstract":"The use of single-domain camelid antibodies, termed VHHs or nanobodies, has found increasing application in diagnosis, pharmaceutical development, and research because of their superior properties, such as small size, elevated stability, high water solubility, and excellent affinity for the antigen. Antigen-specific VHHs are generated by screening VHH display libraries via bio-panning. However, the bio-panning step needs to be repeated multiple times, which is time-consuming and laborious. Here, we developed a simple and rapid screening method that combined Escherichia coli display and a single-step colony assay to successfully identify positive clones from a naïve VHH library. The library was constructed from peripheral blood mononuclear cells of alpaca, and VHHs were displayed on the surface of E. coli using the inverse autotransporter intimin. Libraries enriched by magnetic cell sorting were screened directly using a single-step colony assay. Colonies formed on the hydrophilic filter and antigen-coated membrane. The expression of VHHs was induced, and those bound to the antigen on the membrane were detected as positive clones. Screening and identification of positive clones required only two days, which saves considerable time and resources compared to existing protocols.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"49 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139603409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of Bacteria-Derived Exopolysaccharides in Inflammatory Bowel Disease with a Special Focus on Cyanobacterial Exopolysaccharides","authors":"Devaprakash Manoharan, Sivakumar Natesan, Muriel Billamboz, S. Jawhara","doi":"10.3390/applmicrobiol4010017","DOIUrl":"https://doi.org/10.3390/applmicrobiol4010017","url":null,"abstract":"Instances of inflammatory bowel disease (IBD), a chronic inflammatory condition of the gastrointestinal tract, are rapidly increasing in western and newly industrialized countries. Exopolysaccharides (EPSs) are one of the strategies to enhance the gut microbiota and modulate the immune-inflammatory response deregulation in IBD patients. EPSs are produced by commensal bacteria such as Lactobacillus and Bifidobacterium. Additionally, Cyanobacteria species are promising sources of novel EPS and have potential pharmaceutical and therapeutic applications. The presence of uronic acids and sulphate groups in Cyanobacterial EPSs is an important factor that gives EPSs an anionic charge that is not seen in other prokaryotic species. This feature may impact their physico-chemical characteristics and biological properties. Additionally, Cyanobacterial EPSs have a wide range of biotechnological applications that include use as thickeners, stabilizers, and gelling agents in the food and pharmaceutical sectors. The present review focuses on the role of EPSs in IBD, with a special focus on EPSs derived from Cyanobacteria. This review also covers the biological properties of Cyanobacterial EPS in immuno-inflammatory responses and against pathogens as well as its role in biotechnological applications. Overall, Cyanobacterial EPSs have therapeutic potential against IBD due to their anti-inflammatory and immunoregulatory properties that can reduce inflammation and regulate the immune response and restore the gut microbiota of patients.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"60 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139602910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Toward Effects of Hydrophobicity on Biosurfactant Production by Bacillus subtilis Isolates from Crude-Oil-Exposed Environments","authors":"Seyedeh Zahra Hashemi, J. Fooladi, Maliheh Vahidinasab, Philipp Hubel, J. Pfannstiel, Evelina Pillai, Holger Hrenn, Rudolf Hausmann, Lars Lilge","doi":"10.3390/applmicrobiol4010015","DOIUrl":"https://doi.org/10.3390/applmicrobiol4010015","url":null,"abstract":"Background: Due to their structural features, biosurfactants reveal promising physicochemical properties, making them interesting for various applications in different fields, such as the food, cosmetics, agriculture, and bioremediation sectors. In particular, the bioproduction of surfactin, one of the most potent microbially synthesized biosurfactant molecules, is of great interest. However, since the wild-type productivities are comparably low, stimulatory environmental conditions have to be identified for improved bioproduction This study aims to find a correlation between the hydrophobicity and production of the biosurfactant surfactin by B. subtilis isolates from crude-oil-contaminated soil and water. Methods: The surfactin production yield was characterized in adapted batch cultivations using high-performance thin-layer liquid chromatography (HPTLC). Defined hydrophobic environmental conditions were achieved by supplementation with hexadecane or polystyrene beads, and the effects on biosurfactant production were measured. Adaptations at the protein level were analyzed using mass spectrometry measurements. Results: The correlation between hydrophobicity and surfactin production was characterized using Bacillus subtilis strains ZH1 and P7 isolated from crude-oil-contaminated soil and water. Since these isolates show the biodegradation of crude oil and hexadecane as hydrophobic substrates, respectively, a first-time approach, using polystyrene beads, was applied to provide a hydrophobic environment. Interestingly, contrary to popular opinion, reduced biosurfactant production was determined. Using mass spectrometric approaches, the physiological effects of co-cultivation and the cellular response at the protein level were investigated, resulting in altered quantities of stress proteins and proteins involved in the carbon metabolism counter to polystyrene beads. Conclusions: Contrary to common opinion, increasing hydrophobicity does not have a stimulating effect, and even reduces the effect on the bioproduction of surfactin as the main biosurfactant using selected B. subtilis strains.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"120 27","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139613970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"16S rRNA Gene Sequencing-Based Identification and Comparative Analysis of the Fecal Microbiota of Five Syntopic Lizard Species from a Low-Mountain Area in Western Bulgaria","authors":"I. Lazarkevich, S. Engibarov, Simona Mitova, E. Vacheva, Steliyana Popova, Nikola Stanchev, Rumyana T. Eneva, Y. Gocheva, Ivanka Boyadzhieva, M. Gerginova","doi":"10.3390/applmicrobiol4010013","DOIUrl":"https://doi.org/10.3390/applmicrobiol4010013","url":null,"abstract":"Studies on the gut microbiome of free-living reptiles in Europe are generally fragmentary and still missing in Bulgaria. We aimed to identify and compare the fecal microbiota profiles of five syntopic lizard species from three families: the European green lizard (Lacerta viridis), the common wall lizard (Podarcis muralis), the meadow lizard (Darevskia praticola) (Lacertidae), the European snake-eyed skink (Ablepharus kitaibelii) (Scincidae), and the European slow worm (Anguis fragilis) (Anguidae), which coinhabit a low mountainous area in the western part of the country. A high-throughput sequencing of the hypervariable V3-V4 region of the 16S rRNA gene, performed on the Illumina HiSeq2500 platform, was used. The core microbiota of lizard hosts seems to be species-specific. A dynamic phyla proportion between hosts was found. The richest alpha diversity was observed in D. praticola, and the lowest alpha diversity was observed in P. muralis and A. fragilis. Within the three lacertids, the microbiota of D. praticola and L. viridis were more closely related to each other than they were to those of P. muralis. Sharing a largely common trophic resource (all species except A. fragilis are mainly insectivorous) was not an indication of similarity in their gut microbial communities.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"66 13","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139526729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}