Bioenergy recovery and carbon emissions benefits of short-term bio-thermophilic pretreatment on low organic sewage sludge anaerobic digestion: A pilot-scale study.

Sewage sludge in cities of Yangzi River Belt, China, generally exhibits a lower organic content and higher silt contentdue to leakage of drainage system, which caused low bioenergy recovery and carbon emission benefits in conventional anaerobic digestion (CAD). Therefore, this paper is on a pilot scale, a bio-thermophilic pretreatment anaerobic digestion (BTPAD) for low organic sludge (volatile solids (VS) of 4%) was operated with a long-term continuous flow of 200 days. The VS degradation rate and CH4 yield of BTPAD increased by 19.93% and 53.33%, respectively, compared to those of CAD. The analysis of organic compositions in sludge revealed that BTPAD mainly improved the hydrolysis of proteins in sludge. Further analysis of microbial community proportions by high-throughput sequencing revealed that the short-term bio-thermophilic pretreatment was enriched in Clostridiales, Coprothermobacter and Gelria, was capable of hydrolyzing acidified proteins, and provided more volatile fatty acid (VFA) for the subsequent reaction. Biome combined with fluorescence quantitative polymerase chain reaction (PCR) analysis showed that the number of bacteria with high methanogenic capacity in BTPAD was much higher than that in CAD during the medium temperature digestion stage, indicating that short-term bio-thermophilic pretreatment could provide better methanogenic conditions for BTPAD. Furthermore, the greenhouse gas emission footprint analysis showed that short-term bio-thermophilic pretreatment could reduce the carbon emission of sludge anaerobic digestion system by 19.18%.

Efficient nitrogen removal via simultaneous ammonium assimilation and heterotrophic denitrification of Paracoccus denitrificans R-1.

Although diverse microorganisms can remove ammonium and nitrate simultaneously, their metabolic mechanisms are not well understood. Paracoccus denitrificans R-1 showed the maximal NH4 + removal rate 9.94 mg L-1·h-1 and 2.91 mg L-1·h-1 under aerobic and anaerobic conditions, respectively. Analysis of the nitrogen balance calculation and isotope tracing experiment indicated that NH4 + was consumed through assimilation. The maximal NO3 - removal rate of strain R-1 was 18.05 and 19.76 mg L-1·h-1 under aerobic and anaerobic conditions, respectively. The stoichiometric consumption ratio of acetate to nitrate was 0.902 and NO3 - was reduced to N2 for strain R-1 through 15NO3 - isotopic tracing experiment, which indicated a respiratory process coupled with the oxidation of electron donors. Genomic analysis showed that strain R-1 contained genes for ammonium assimilation and denitrification, which effectively promoted each other. These findings provide insights into microbial nitrogen transformation and facilitate the simultaneous removal of NH4 + and NO3 - in a single reactor.

Rifampicin tolerance and growth fitness among isoniazid-resistant clinical Mycobacterium tuberculosis isolates from a longitudinal study.

Antibiotic tolerance in Mycobacterium tuberculosis reduces bacterial killing, worsens treatment outcomes, and contributes to resistance. We studied rifampicin tolerance in isolates with or without isoniazid resistance (IR). Using a minimum duration of killing assay, we measured rifampicin survival in isoniazid-susceptible (IS, n=119) and resistant (IR, n=84) isolates, correlating tolerance with bacterial growth, rifampicin minimum inhibitory concentrations (MICs), and isoniazid-resistant mutations. Longitudinal IR isolates were analyzed for changes in rifampicin tolerance and genetic variant emergence. The median time for rifampicin to reduce the bacterial population by 90% (MDK90) increased from 1.23 days (IS) and 1.31 days (IR) to 2.55 days (IS) and 1.98 days (IR) over 15-60 days of incubation, indicating fast and slow-growing tolerant sub-populations. A 6 log10-fold survival fraction classified tolerance as low, medium, or high, showing that IR is linked to increased tolerance and faster growth (OR = 2.68 for low vs. medium, OR = 4.42 for low vs. high, p-trend = 0.0003). High tolerance in IR isolates was associated with rifampicin treatment in patients and genetic microvariants. These findings suggest that IR tuberculosis should be assessed for high rifampicin tolerance to optimize treatment and prevent the development of multi-drug-resistant tuberculosis.

Machine learning approaches identify immunologic signatures of total and intact HIV DNA during long-term antiretroviral therapy.

Understanding the interplay between the HIV reservoir and the host immune system may yield insights into HIV persistence during antiretroviral therapy (ART) and inform strategies for a cure. Here, we applied machine learning (ML) approaches to cross-sectional high-parameter HIV reservoir and immunology data in order to characterize host-reservoir associations and generate new hypotheses about HIV reservoir biology. High-dimensional immunophenotyping, quantification of HIV-specific T cell responses, and measurement of genetically intact and total HIV proviral DNA frequencies were performed on peripheral blood samples from 115 people with HIV (PWH) on long-term ART. Analysis demonstrated that both intact and total proviral DNA frequencies were positively correlated with T cell activation and exhaustion. Years of ART and select bifunctional HIV-specific CD4 T cell responses were negatively correlated with the percentage of intact proviruses. A leave-one-covariate-out inference approach identified specific HIV reservoir and clinical-demographic parameters, such as age and biological sex, that were particularly important in predicting immunophenotypes. Overall, immune parameters were more strongly associated with total HIV proviral frequencies than intact proviral frequencies. Uniquely, however, expression of the IL-7 receptor alpha chain (CD127) on CD4 T cells was more strongly correlated with the intact reservoir. Unsupervised dimension reduction analysis identified two main clusters of PWH with distinct immune and reservoir characteristics. Using reservoir correlates identified in these initial analyses, decision tree methods were employed to visualize relationships among multiple immune and clinical-demographic parameters and the HIV reservoir. Finally, using random splits of our data as training-test sets, ML algorithms predicted with approximately 70% accuracy whether a given participant had qualitatively high or low levels of total or intact HIV DNA . The techniques described here may be useful for assessing global patterns within the increasingly high-dimensional data used in HIV reservoir and other studies of complex biology.

Metformin facilitates viral reservoir reactivation and their recognition by anti-HIV-1 envelope antibodies.

The mechanistic target of rapamycin (mTOR) positively regulates multiple steps of the HIV-1 replication cycle. We previously reported that a 12-week supplementation of antiretroviral therapy (ART) with metformin, an indirect mTOR inhibitor used in type-2 diabetes treatment, reduced mTOR activation and HIV transcription in colon-infiltrating CD4+ T cells, together with systemic inflammation in nondiabetic people with HIV-1 (PWH). Herein, we investigated the antiviral mechanisms of metformin. In a viral outgrowth assay performed with CD4+ T cells from ART-treated PWH, and upon infection in vitro with replication-competent and VSV-G-pseudotyped HIV-1, metformin decreased virion release, but increased the frequency of productively infected CD4lowHIV-p24+ T cells. These observations coincided with increased BST2/tetherin (HIV release inhibitor) and Bcl-2 (pro-survival factor) expression, and improved recognition of productively infected T cells by HIV-1 envelope antibodies. Thus, metformin exerts pleiotropic effects on post-integration steps of the HIV-1 replication cycle and may be used to accelerate viral reservoir decay in ART-treated PWH.

Autographiviridae phage HH109 uses capsular polysaccharide for infection of Vibrio alginolyticus.

Autographiviridae phage HH109 is a lytic Vibrio alginolyticus E110-specific phage, but the molecular mechanism underlying host recognition of this phage remains unknown. In this study, a transposon mutagenesis library of E110 was used to show that several capsular polysaccharide (CPS) synthesis-related genes were linked to the phage HH109 infection. Gene deletion combined with multiple functional assays demonstrated that CPS serves as the receptor for the phage HH109. Deletions of CPS genes caused reduction or loss of capsule and reduced adsorption. Comparative genome analysis revealed that phage-resistant mutants harbored loss-of-function mutations in the previously identified genes responsible for CPS biosynthesis. The tail protein gp02 of phage HH109 was identified as the receptor-binding protein (RBP) on CPS using antibody blocking assay, immunofluorescence staining, and CPS quantification. Additionally, we found that the phage HH109 could degrade approximately 88% of mature biofilms. Our research findings provide a theoretical basis against vibriosis.

Changes in performance, cecal microflora counts and intestinal histology of Japanese quails fed diets containing different fibre sources.

The purpose of this experiment was to investigate how various fiber sources impact the performance, microbial population, and intestinal histology of Japanese quail that was performed in a completely randomized design for 42 days. The dietary treatments involved a fiber-free corn-soybean meal-based diet (control, CTL), and CTL with added levels of sunflower hulls (SFH) and sugar beet pulp (SBP) (20 and 40 g kg-1). Body weight gain (BWG) and feed intake (FI) were recorded weekly. Carcass characteristics, cecal microbial population, blood variables and intestinal histology were measured on the 42 day of age. Adding 40 g kg-1 of SBP led to a significant decrease in body weight gain and an increase in the feed conversion ratio of birds from 1 to 21 days (P < 0.05). The relative weight of the gastrointestinal tract and gizzard increased significantly in birds that consumed SFH. Blood triglyceride concentration decreased with the inclusion of fiber in the diet. However, there was a notable increase in blood cholesterol concentration in the birds that were fed SBP (20 and 40 g kg-1) in comparison to those fed SFH (P < 0.05). The population of E. Coli in the cecum increased significantly in the birds that were fed 4 g kg-1 of SBP as opposed to those fed 20 and 40 g kg-1 of SFH (P < 0.05). The villus height of the jejunum in birds that were fed 20 g kg-1 and 40 g kg-1 of SFH demonstrated a significant increase in comparison to the other treatments (P < 0.05). In general, the findings of this research indicated that the inclusion of 40 g kg-1 of SBP in the diet had a negative impact on performance and other physiological parameters. However, the use of SFH and 20 g kg-1 of SBP yielded similar results to birds in the CTL, and in some cases, even better outcomes.

Meta-analysis of oral microbiome reveals sex-based diversity in biofilms during periodontitis.

Sex is an often overlooked, yet compulsory, biological variable when performing biomedical research. Periodontitis is a common yet progressively debilitating chronic inflammatory disorder affecting the tissues supporting teeth that ultimately leads to tooth loss if left untreated. The incidence of periodontitis is sex biased, with increased prevalence in males compared with females but with unknown etiology. We performed a sex-specific meta-analysis using publicly available oral microbiome data from different sampling sites of patients with periodontitis and periodontally healthy controls; sex balance was established for each periodontal health condition. Our results show sex-based diversity in oral biofilms of individuals with periodontitis but not in their saliva, with increased abundance of several periodontal pathogens in subgingival plaques from females compared with males. We devised a quantitative measure, uniquely defined as the Microsexome Index (MSI), which indicates that sexual dimorphism in subgingival bacterial composition is a distinct feature of reduced microbial diversity during periodontitis but not under healthy conditions. In addition, we found that smoking exacerbates microsexome diversity in supragingival biofilms, particularly during periodontitis. Taken together, we provide insights regarding sex-based diversity in periodontitis, a disease with multiorgan associations, and provide the rationale for further mechanistic, diagnostic, and therapeutic studies.

Protocol for rapid and cost-effective extraction of genomic DNA from a wide range of wild yeast species for use in PCR-based applications.

Isolation of amplifiable genomic DNA is a prerequisite for the implementation of PCR-based techniques. Here we present a protocol for isolating the genomic DNA from a variety of wild yeast species. This can be completed in approximately 1 h and does not require sophisticated laboratory equipment. We describe steps for growing yeast cells, genomic data extraction, and downstream assay for amplification of specific sequences from the genomic DNA. We then detail procedures for gel electrophoresis and analysis of the results. For complete details on the use and execution of this protocol, please refer to Kristjuhan et al.1.

Surgical site infection in severe trauma patients in intensive care: epidemiology and risk factors.

BACKGROUND: Severe trauma is the leading cause of disability and mortality in the patients under 35 years of age. Surgical site infections (SSI) represent a significant complication in this patient population. However, they are often inadequately investigated, potentially impacting the quality of patient outcomes. The aim of this study was to investigate the epidemiology of SSI and risk factors in severe trauma patients. METHODS: We conducted a multicenter retrospective cohort study screening the severe trauma patients (STP) admitted to two intensive care units of an academic institution in Marseille between years2018 and 2019. Those who underwent orthopedic or spinal surgery within 5 days after admission were included and classified into two groups according to the occurrence of SSI (defined by the Centers for Disease Control (CDC) international diagnostic criteria) or not. Our secondary goal was to evaluate STP survival at 48 months, risk factors for SSI and microbiological features of SSI. RESULTS: Forty-seven (23%) out of 207 STP developed an SSI. Mortality at 48-months did not differ between SSI and non-SSI patients (12.7% vs. 10.0%; p = 0.59). The fractures of 22 (47%) severe trauma patients with SSI were classified as Cauchoix 3 grade and 18 (38%) SSI were associated with the need for external fixators. Thirty (64%) severe trauma patients with SSI had polymicrobial infection, including 34 (72%) due to Gram-positive cocci. Empirical antibiotic therapy was effective in 31 (66%) cases. Multivariate analysis revealed that risk factors such as low hemoglobin, arterial oxygenation levels, hyperlactatemia, high serum creatinine and glycemia, and Cauchoix 3 grade on the day of surgery were associated with SSI in severe trauma patients. The generated predictive model showed a good prognosis performance with an AUC of 0.80 [0.73-0.88] and a high NPV of 95.9 [88.6-98.5] %. CONCLUSIONS: Our study found a high rate of SSI in severe trauma patients, although SSI was not associated with 48-month mortality. Several modifiable risk factors for SSI may be effectively managed through enhanced perioperative monitoring and the implementation of a patient blood management strategy.

Acute and persistent responses after H5N1 vaccination in humans.

To gain insight into how an adjuvant impacts vaccination responses, we use systems immunology to study human H5N1 influenza vaccination with or without the adjuvant AS03, longitudinally assessing 14 time points including multiple time points within the first day after prime and boost. We develop an unsupervised computational framework to discover high-dimensional response patterns, which uncover adjuvant- and immunogenicity-associated early response dynamics, including some that differ post prime versus boost. With or without adjuvant, some vaccine-induced transcriptional patterns persist to at least 100 days after initial vaccination. Single-cell profiling of surface proteins, transcriptomes, and chromatin accessibility implicates transcription factors in the erythroblast-transformation-specific (ETS) family as shaping these long-lasting signatures, primarily in classical monocytes but also in CD8+ naive-like T cells. These cell-type-specific signatures are elevated at baseline in high-antibody responders in an independent vaccination cohort, suggesting that antigen-agnostic baseline immune states can be modulated by vaccine antigens alone to enhance future responses.

Pathogenic Bacteria and Antimicrobial Resistance in Hospital-Acquired Urinary Tract Infections among Patients with Diabetic Nephropathy.

OBJECTIVE: Hospital-acquired urinary tract infections (UTIs) are common complications in patients with diabetic nephropathy (DN), leading to increased mortality and increased medical resource utilisation. This study investigated hospital-acquired UTIs in patients with DN, focusing on prevalent pathogens and drug resistance to inform clinical management. METHODOLOGY: This retrospective study analysed 141 patients with hospital-acquired UTIs admitted to The Affiliated Hospital of Qingdao University from January 1, 2013 to December 31, 2022, using the Yidu Cloud database. Among them, 109 had DN, and 32 had nondiabetic nephropathy (NDN). Patient demographics, pathogen distribution, and antibiotic resistance were statistically evaluated. RESULTS: The incidence of hospital-acquired UTIs was significantly higher in patients with DN compared to those with NDN (p < 0.0001), with a higher prevalence in women (p = 0.004). Gram-negative bacteria, particularly Escherichia coli (E. coli) and Klebsiella pneumoniae, were the primary pathogens in patients with DN and NDN. E. coli infections were more common in the DN group (p = 0.017). These pathogens exhibited high susceptibility to carbapenems, ß-lactamase inhibitors, amikacin, nitrofurantoin, and minocycline; However, they showed significant resistance to quinolones, cephalosporin, and penicillins. CONCLUSIONS: Preventing hospital-acquired UTIs in patients with DN is crucial. Effective treatment requires selecting antibacterial drugs based on pathogen resistance profiles.

Helicobacter pylori in oral cavity: current knowledge.

The oral cavity may play a role as a reservoir and in the transmission and colonization of Helicobacter pylori. The route of transmission for H. pylori is not fully understood. The prevalence of this pathogen varies globally, affecting half of the world's population, predominantly in developing countries. Here, we review the prevalence of H. pylori in the oral cavity, the characteristics that facilitate its colonization and dynamics in the oral microbiome, the heterogeneity and diversity of virulence of among strains, and noninvasive techniques for H. pylori detection in oral samples. The prevalence of H. pylori in the oral cavity varies greatly, being influenced by the characteristics of the population, regions where samples are collected in the oral cavity, and variations in detection methods. Although there is no direct association between the presence of H. pylori in oral samples and stomach infection, positive cases for gastric H. pylori frequently exhibit a higher prevalence of the bacterium in the oral cavity, suggesting that the stomach may not be the sole reservoir of H. pylori. In the oral cavity, H. pylori can cause microbiome imbalance and remodeling of the oral ecosystem. Detection of H. pylori in the oral cavity by a noninvasive method may provide a more accessible diagnostic tool as well as help prevent transmission and gastric re-colonization. Further research into this bacterium in the oral cavity will offer insights into the treatment of H. pylori infection, potentially developing new clinical approaches.

Cronobacter sakazakii induced sepsis-associated arrhythmias through its outer membrane vesicles.

Sepsis-induced arrhythmia, linked to sudden cardiac death, is associated with gut microbiota, though the exact relationship is unclear. This study aimed to elucidate the relationship between Cronobacter sakazakii (C. sakazakii) and arrhythmia. The relative abundance of C. sakazakii was increased in cecal ligation and puncture (CLP)-induced septic mice. Live C. sakazakii, supernatant, and outer membrane vesicles (OMVs) resulted in premature ventricular beat (PVB), sinus arrhythmia (SA), and increased arrhythmia and mortality in sepsis model through dysregulated ion channel proteins. Moreover, short-chain fatty acids (SCFAs) showed antibacterial effects in vitro. We confirmed sodium acetate (C2) and sodium butyrate (C4) protect from C. sakazakii-induced arrhythmia, and C2 and C4 protected from septic arrhythmia by activating free fatty acid receptor 2 and 3 (FFAR2 and FFAR3) in mice. These findings point to how C. sakazakii's OMVs trigger arrhythmia, and SCFAs may be a treatment for septic arrhythmia.

Epidemiological, Phylogenetic, and Resistance Heterogeneity Among Acinetobacter baumannii in a Large U.S. Deep South Healthcare system.

Background: Acinetobacter baumannii (Ab) disease in the United States is commonly attributed to outbreaks of 1 or 2 monophyletic carbapenem resistance (CR) Ab lineages that vary by region. However, there is limited knowledge regarding CRAb epidemiology and population structures in the U.S. Deep South, and few studies compare contemporary CR and carbapenem-susceptible (Cs) Ab, despite relative prevalence of the latter. Methods: We performed a multiyear analysis of 2462 Ab cases in a large healthcare system in Birmingham, AL, and 89 post-2021 Ab isolates were sequenced and phenotyped by antibiotic susceptibility tests. Results: Although the cumulative CR rate was 17.7% in our cohort, rates regularly increased in winter months as result of seasonal changes in case incidence of CsAb, specifically. Genotyped CRAb belonged to clonal group (CG) 1, CG2, CG108, CG250, or CG499, with local clones of CG108, CG250, and CG499 persisting over multiple months. There was no clonal expansion of any CsAb lineage. Among CRAb isolates, levels of ß-lactam antibiotic resistance and the repertoire of related genetic resistance determinants, which included the novel CR-conferring FtsI A515V polymorphism, differed according to CG. CG108 and CG499 isolates displayed specific heteroresistance to sulbactam and trimethoprim/sulfamethoxazole, respectively, which resulted in discrepant susceptibility results in microbroth versus agar-based antibiotic susceptibility tests modalities. Conclusions: We report an unusually high degree of CRAb phylogenetic diversity principally driven by emergent U.S. lineages harboring novel resistance elements that must be incorporated into diagnostic, surveillance, and preclinical research efforts.

ENOVAT: the European Network for Optimization of Veterinary Antimicrobial Treatment.

The global antimicrobial resistance crisis has been the driver of several international strategies on antimicrobial stewardship. For their implementation on field level, the veterinary sector encounters several specific challenges and in particular: (i) a shortage of experts in key disciplines related to antimicrobial stewardship, (ii) a lack of evidence-based antimicrobial treatment guidelines, and (iii) inferior diagnostic tests available compared to human medicine. The present white paper describes how the COST Action ENOVAT (the European Network for Optimization of Veterinary Antimicrobial Treatment, CA18217), comprising 332 persons from 51 countries, worked towards solutions to these challenges. Initially, surveys were conducted to explore the present state in Europe in terms of existing antimicrobial use guidelines and microbiology practices performed. Concurrently, various research activities were launched to optimize diagnostics, including development of epidemiological cut-offs, clinical breakpoints and matrix-assisted laser desorption ionization time of flight mass spectrometry interpretive criteria. Also, guidelines drafting groups working towards evidence-based antimicrobial treatment guidelines for six conditions in food-producing and companion animals were established. The processes and outcomes, also in terms of capacity building, are summarized in this white paper where emphasis is placed on sustainability of the activities. Although several ENOVAT initiatives and spin-off projects will continue beyond the Action, we recommend that a new European veterinary research agenda is launched focusing on research and funding leading to long-term impacts on veterinary antimicrobial use.

Antimicrobial resistance is an urgent global public health threat that is amplified by over- and misuse of antimicrobials. As a result of antimicrobial resistance, antibiotics and other antimicrobial medicines become ineffective and infections become difficult or impossible to treat. This goes for human infections, but also for infections in animals. In a recently finished European project called ENOVAT we tried to tackle the problem of antimicrobial resistance in animals. We focused on two topics. First we optimized and harmonized diagnostics of bacterial infections in the laboratory, and second we developed evidence-based treatment guidelines to support veterinary practitioners on how and when to use antibiotics in the best way. Improved diagnostics and new treatment guidelines can help veterinary practitioners to a more sensible antibiotic choice and with that less over- and misuse of antimicrobials. This article summarizes the process and progress of the work done in the ENOVAT project. Emphasis is also put on how the project benefitted from a unique consortium encompassing 332 professionals with diverse backgrounds, from 51 countries.

Integration of soil microbiology and metabolomics to elucidate the mechanism of the accelerated infestation of tobacco by the root-knot nematode.

Introduction: Tobacco root-knot nematode (TRKN) disease is a soil-borne disease that presents a major hazard to the cultivation of tobacco, causing significant reduction in crop quality and yield, and affecting soil microbial diversity and metabolites. However, differences in rhizosphere soil microbial communities and metabolites between healthy tobacco soils and tobacco soils with varying degrees of TRKN infection remain unclear. Methods: In this study, diseased rhizosphere soils of tobacco infected with different degrees of TRKN [severally diseased (DH) soils, moderately diseased (DM) soils, and mildly diseased (DL) soils] and healthy (H) rhizosphere soils were collected. Here, we combined microbiology with metabolomics to investigate changes in rhizosphere microbial communities and metabolism in healthy and TRKN-infected tobacco using high-throughput sequencing and LC-MS/MS platforms. Results: The results showed that the Chao1 and Shannon indices of bacterial communities in moderately and mildly diseased soils were significantly higher than healthy soils. The Proteobacteria, Actinobacteria, Ascomycota, Burkholderia, Bradyrhizobium and Dyella were enriched in the rhizosphere soil of healthy tobacco. Basidiomycota, Agaricales, Pseudeurotiaceae and Ralstonia were enriched in severally diseased soils. Besides, healthy soils exhibited a relatively complex and interconnected network of bacterial molecular ecologies, while in severally and moderately diseased soils the fungal molecular networks are relatively complex. Redundancy analysis showed that total nitrogen, nitrate nitrogen, available phosphorus, significantly affected the changes in microbial communities. In addition, metabolomics results indicated that rhizosphere soil metabolites were significantly altered after tobacco plants were infected with TRKNs. The relative abundance of organic acids was higher in severally diseased soils. Spearman's analyses showed that oleic acid, C16 sphinganine, 16-hydroxyhexadecanoic acid, D-erythro-3-methylmalate were positively correlated with Basidiomycota, Agaricales, Ralstonia. Discussion: In conclusion, this study revealed the relationship between different levels of TRKN invasion of tobacco root systems with bacteria, fungi, metabolites and soil environmental factors, and provides a theoretical basis for the biological control of TRKN disease.

David Taylor-Robinson: Medical Microbiologist and Research Pioneer of Sexually Transmitted Infections.

David Taylor-Robinson has been an inspiration to many investigators in the field of sexually transmitted infections (STIs) as, arguably, the father of modern mycoplasmology. Born in 1931, his career as a physician-scientist was initially in virology, researching chickenpox and the common cold, for both of which he made key discoveries at a time when little was known about these conditions. Soon, however, David's attention turned to bacteriology, developing a passionate interest in mycoplasmas and chlamydia. This gave rise to research collaborations all around the world in marginalized and regional communities, stretching from Tristan da Cunha and Antarctica to the South Pacific and sub-Saharan Africa. He was the discoverer of Mycoplasma genitalium, which today is a commonly diagnosed and increasingly antibiotic-resistant pathogen of the genitourinary tract and a significant cause of female infertility. His problem-solving mindset led to research on associations between mycoplasmas with rheumatological conditions and chlamydia with coronary artery plaque formation late into his working life. Throughout his distinguished career, David Taylor-Robinson, affectionately truncated to "DTR" to all who knew him professionally, has been a beloved mentor to hundreds of aspiring scientists, some of whom are now leaders in their field. His open-door policy meant that there was rarely a time when there was no visiting researcher from each of the six inhabited continents under his expert tutelage. A strong work ethic and drive for scientific excellence, allied to his unstinting kindness and jovial demeanor, has provided a source of inspiration to a wide diaspora of research colleagues over more than six decades. This is as much David's legacy to medical science as the undoubted public health impact of his own pioneering research on STIs.

Bacillus cereus infection of the penis: an unusual infection.

Background: Bacillus cereus (B. cereus) is a Gram-positive, rod-shaped, motile organism, found in the environment and may exist in contaminated food sources such as reheated rice, vegetables and may lead to gastrointestinal symptoms after ingestion including diarrhea, nausea, and vomiting due to enterotoxigenic and emetic toxins. Non-gastrointestinal infections of Bacillus cereus have been reported in the literature, which include cutaneous and non-cutaneous infections in immunocompetent and immunocompromised individuals. Case presentation: A 38-year-old man presented with a one-week history of penile swelling and redness that started after an episode of severe diarrhea and vomiting, which soiled his genital region few hours after vigorous intercourse with his wife. This has led to infection of the penile skin by an unusual organism: Bacillus (B.) cereus. The patient was treated using fucidic acid ointment applications for 2 weeks achieving complete recovery. Clinical discussion: The recovery of B. cereus from the penile infection in our patient reveals the first case of such an unusual infection, though this pathogen has been reported to cause a wide range of non-GI tract infections, which include bacteremia, meningitis, endocarditis, endophthalmitis, pneumonia, and soft tissue diseases. Virulence factors allow this organism to induce diarrhea in addition to having dermonecrotic, cytotoxic, hemolytic properties resulting in a wide range of dermatologic presentations. Conclusion: The authors report a unique case of penile skin infection caused by B. cereus, an unusual culprit for an uncommon presentation successfully treated with fucidic acid ointment. This is the first case in literature describing such an entity.