Optimization of petroleum hydrocarbon degradation process in contaminated environments could be feasible using biosurfactant-producing bacteria. The aim of this study was to investigate crude oil degradation potential of biosurfactant-producing bacteria isolated from a marine ecosystem in Nigeria. Sediment and water samples were collected from ten marine locations in Nigeria, and physicochemical analyses were carried out on them. Isolates were identified and screened for biosurfactant production and crude oil degradation after 7 days of incubation. The screened isolates were assayed for biosurfactant production and crude oil degradation for 35 days and analysed every 7 days for changes in pH, OD and total petroleum hydrocarbon content. The strains with the highest yields were identified using PCR-based molecular method. Twenty bacterial species were isolated from the marine locations, and 15 of these isolates showed good potential for biosurfactant production and crude oil degradation. The isolates with the highest biosurfactant production using oil spread and emulsification index tests are Pseudomonas aeruginosa Sihong_820_11, P. aeruginosa Strain P73 and Atlantibacter hermannii Strain K167. In addition, these bacterial isolates have the highest crude oil degradation efficiencies of 87%, 68% and 68%, respectively. The findings revealed that biosurfactant-producing bacteria isolated from marine ecosystems within Nigeria could effectively degrade crude oil in contaminated sites. In addition, bacteria with higher potential for biosurfactant production are more efficient in crude oil degradation.

Bioluminescent bioreporters are widely used across various scientific disciplines due to the well-characterized bacterial bioluminescence mechanism. However, solvent-induced membrane perturbations may confound the use of bioreporters in assessing cellular toxicity from environmental contaminants. This study investigated the solvent effect, wherein membrane damage increases intracellular availability of bioluminescent reaction precursors, increasing the light produced. A new online in situ monitoring system was also tested with multiple bioluminescent reporters, including a newly constructed Pseudomonas fluorescens M3A strain, exposed to toluene, trichloroethylene, acetone, phenol and creosote derived from beechwood tar. Additional tests included the introduction of carbon nanotubes, fullerene and fullerenol. A solvent effect was confirmed by the detection of increased bioluminescent signal and the occurrence of fatty acid release (P<0.05). Phenol (25 p.p.m.), a benchmark for bactericidal activity, demonstrated luminescence enhancement via the solvent effect. Membrane toxicity assays showed that P. fluorescens M3A responded sensitively to sublethal and lethal membrane disruptions, whereas Vibrio fischeri MJ1 did not exhibit a solvent effect, and its luminescence changes were not correlated with viability (P>0.05). These results indicate that P. fluorescens M3A is a sensitive biosensor for detecting environmental contaminants and identifying both lethal and sublethal membrane perturbations. The findings underscore essential considerations when utilizing bacterial bioluminescence as a proxy for gene expression or cellular physiology.

Duplication and segregation of genetic material are vital for cell proliferation. Deletion of DNA replication regulators, such as YabA and ParA, leads to over-initiation of DNA replication. However, the viability of the ΔyabA ΔparA double mutant suggests additional regulatory mechanisms. Using a transposon mutagenesis library, yybE was identified as a potential candidate. Bioinformatic analysis of yybE suggests that it encodes a putative LysR-type transcriptional regulator (LTTR). LTTRs are established regulators of metabolic processes, leading to the hypothesis that YybE might link metabolic processes to DNA replication. However, under the tested conditions, deletion of yybE did not result in detectable changes to DNA replication frequency, origin segregation or chromosome morphology.

The Ralstonia solanacearum species complex (RSSC) is a globally distributed group of Gram-negative, soil-borne bacteria that cause wilt diseases on a broad range of hosts. Due to these pathogens’ impact on economically important plant species, there is a need for consolidated and visualized information on RSSC pathogen isolation data. We developed an interactive dashboard designed to allow users to explore the diversity and biogeography of the RSSC. The dashboard visualizes data in the form of maps, charts and tables, with a variety of user-interactive filters for taxonomic, geographic and host of isolation specifications. This Ralstonia Wilt Dashboard will aid in communicating knowledge to researchers, regulatory scientists and other stakeholders to improve disease control and regulation. This report highlights the deployment of the Ralstonia Wilt Dashboard and provides four case studies that address focused, scientific questions (https://ralstoniadashboard.shinyapps.io/RalstoniaWiltDashboard/).

Background.Bartonella species are increasingly recognized as a significant cause of blood culture–negative infective endocarditis. Their diagnosis is often challenging, leading to delays and suboptimal treatment outcomes.Case report. This report includes a concise literature review and a case involving a 77-year-old male with a history of bovine aortic valve replacement. The patient presented with lethargy, fever, unintentional weight loss and acute kidney injury. Despite repeated blood cultures and extensive diagnostic evaluations yielding negative results, the definitive diagnosis was achieved post-surgery when valve PCR identified Bartonella species, likely linked to cat exposure. The patient was successfully treated with an extended course of doxycycline and rifampicin, leading to clinical resolution.Conclusion. This case highlights the diagnostic complexities of Bartonella endocarditis, including negative blood cultures, subacute clinical presentation and its ability to mimic autoimmune glomerulonephritis, leading to unnecessary immunosuppressive therapy. It underscores the need for improved diagnostic approaches and clinician awareness to identify at-risk populations, such as those with cat exposure or poor hygiene, ensuring the correct diagnostic investigation for an early antibiotic intervention.

Meyerozyma guilliermondii, a haploid yeast (phylum Ascomycota), is useful in bioprocessing and bioremediation, and is an infrequent pathogen of humans. The availability of highly accurate, long-read DNA sequencing methods provided the opportunity to improve the M. guilliermondii genome assembly. Using Pacific Biosciences (PacBio) HiFi technology, we generated a chromosome-level, telomere-to-telomere assembly for the M. guilliermondii type strain ATCC 6260. This assembly closed gaps in the current reference sequence and resolved a translocation artefact that affected the size and structure of chromosomes 4 and 5. The improved genome sequence is available publicly and will facilitate future studies of this species.

Background. Carbapenem-resistant Gram-negative bacteria (CR-GNB), particularly metallo-β-lactamase (MBL) producers, are WHO critical-priority pathogens. In Libya, laboratory-based data are scarce, and no study has assessed endemic medicinal plants as adjunctive options. Objectives. To generate baseline data on carbapenem resistance and MBL production among clinical Gram-negative pathogens in Misurata, Libya, and to preliminarily evaluate the antibacterial activity and phytochemical composition of Arbutus pavarii extracts. Methods. We conducted a cross-sectional study of 244 non-duplicate clinical isolates. Carbapenem susceptibility was determined by Kirby-Bauer disc diffusion; MBL production was confirmed by double-disc synergy and combined-disc tests. Ethanolic and aqueous extracts from A. pavarii leaves, stems and fruits were tested against resistant isolates by disc diffusion. Phytochemicals were profiled by HPLC. Results. The predominant carbapenem-resistant species were Acinetobacter baumannii (29.5%), Klebsiella pneumoniae (26.2%) and Pseudomonas aeruginosa (19.7%). Resistance to both imipenem and meropenem exceeded 60% across these isolates, and MBL activity was detected in 54.5% of carbapenem-resistant K. pneumoniae. Among plant extracts, the aqueous leaf extract showed the highest antibacterial activity against MBL-producing isolates (mean inhibition zone 9.46±7.61 mm at 100%), slightly exceeding the corresponding ethanolic extract (9.31±7.30 mm). Both extracts demonstrated concentration-dependent effects (P<0.05; ANOVA/Kruskal-Wallis). HPLC analysis identified catechin and quercetin as major components, which may underlie the observed activity. Conclusions. This first laboratory-based report from Libya documents high rates of CR-GNB and MBL production and introduces A. pavarii as a promising endemic plant with adjunctive antibacterial potential. Findings support enhanced AMR surveillance and the exploration of resource-sensitive alternatives in African healthcare settings.

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal disorder in preterm infants with a high mortality rate. The aetiology of NEC appears to be multifaceted; however, gut microbiota dysbiosis likely plays a significant role. This systematic review aimed to describe how the gut microbiota of preterm infants with NEC differs from infants without NEC (PROSPERO: CRD42022344126). Databases were searched from inception to 22 June 2022 to identify eligible studies that examined the gut microbiota composition of preterm infants with and without NEC using sequencing methods. Results were described narratively. We identified 28 eligible studies. Overall, findings were heterogeneous and no single gut microbiota signature was associated with NEC in all studies. Importantly, 3 studies reported no difference in the gut microbiota composition between NEC and healthy infants, while studies reported a difference using one or more analytical method (i.e. alpha diversity, beta diversity or differential abundance analysis). Of note, NEC (or development of NEC) was positively associated with increased detection and/or abundance of Enterobacteriaceae (n=11 studies), Clostridium (n=8) and Proteobacteria (n=2). The taxa most frequently associated with NEC (Enterobacteriaceae, Clostridium, and Proteobacteria) may play an important role in the pathogenesis of NEC and should be further explored.

Background. Nitrate-dependent iron (Fe 2+ ) oxidation (NDFO) is an important biogeochemical process, but whether NDFO provides a direct metabolic benefit to facultative anaerobes with diverse lifestyles, such as Salmonella enterica , and what role the respiratory nitrate reductases play in this process is unknown. Methods. This study investigated NDFO in S. enterica serovar Typhimurium strain SL1344. We compared the WT strain with a ∆ narGHIJ ∆ narZYW mutant (∆ nar ), which lacks the primary respiratory nitrate reductase (Nar). Cultures were grown anaerobically in lysogeny broth medium amended with 4 mM nitrate and 10 mM FeSO₄ as defined nitrate and iron sources. Growth, nitrate depletion, nitrite accumulation, and Fe 2+ oxidation were monitored over 14 days. Abiotic controls amended with either nitrate or nitrite were included to control for abiotic iron oxidation. Results. There was no significant difference in the growth rate and biomass production between the WT and ∆ nar strains. However, there was significant variation in nitrite reduction and iron oxidation. 56.9% of the nitrate was depleted from the growth medium (initially 4 mM) with the WT cultures compared to 19.7% with the ∆ nar strain. Fe 2+ oxidation in the WT cultures reached a Fe² + /Fe total ratio of ~0.52–0.61 during exponential growth and was consistent during the stationary phase, whereas for the mutant, the maximum Fe² + /Fe total ratio was ~0.78, which returned to a more reduced state in stationary phase (Fe² + /Fe total ~0.95). Abiotic controls amended with nitrite showed rapid Fe 2+ oxidation, highlighting the role of nitrite as an oxidant. Conclusion. The respiratory nitrate reductases are the primary drivers of NDFO in S. enterica SL1344 and are required for the generation of nitrite, which then abiotically oxidizes Fe 2+ to Fe 3+ . This did not confer a growth advantage, suggesting NDFO is an indirect consequence of nitrate respiration rather than a direct energy-conserving pathway in this organism.

Tuberculosis (TB) remains a large global health threat, including increasing cases in generally low-incidence areas of the USA. However, the knowledge, attitudes and practices (KAP) regarding TB in these low-incidence areas are underexplored, precluding planning for effective health communication in these areas regarding travel to high-incidence areas or potential future outbreaks in currently low-incidence areas. Using the health belief model as a theoretical framework, we developed a KAP survey to assess public perceptions of TB in Colorado, a currently low-incidence area. We collected complete responses from n=225 adults. We found that participants had higher self-assessed knowledge than actual knowledge about TB. We also found that while participants recognized TB as a global health threat, they were not personally worried about contracting TB. However, a portion of participants indicated that they would feel shame if they contracted TB. Public knowledge and risk perception about TB could be improved by providing information in low-incidence areas on the public health burden of TB. Additionally, providing health communication to focus on emotion management and reducing stigma about the disease would be important to promote healthcare-seeking and treatment compliance in case of a future outbreak.