The primary objective of the current work was to determine whether pH could be used as a proxy measure for bacterial contamination (using reference standard sheep blood agar plates to measure total bacteria counts [TBCs] and MacConkey agar plates to measure total coliform counts [TCCs]) of bovine colostrum (BC). The hypothesis for this work was that bacteria produce acid by-products from their metabolism, thereby more highly contaminated BC is likely to be more acidic, based on lower pH measurement. A secondary objective was to identify optimal thresholds for pH to identify colostrum highly contaminated with total bacteria or coliform species, with industry thresholds for highly contaminated colostrum being TBCs > 100,000 CFU/mL and TCCs > 10,000 CFU/mL. One hundred and one samples were purposively selected from previously frozen BC samples. Sample pH was measured using a pH meter in duplicate, and bacteria counts were measured using the reference tests of 5% sheep blood agar and MacConkey agar plates for TBC and TCC, respectively. Small decreases in pH measurement were associated with increases in bacterial contamination of BC, particularly coliform species, which are those most implicated in the disruption of IgG absorption from colostrum. There was a statistically significant relationship between pH measurements and log-transformed bacterial measurements.

Literature about the discovery of the leprosy bacterium Mycobacterium leprae usually mentions the Hansen-Neisser controversy. It is an established narrative that Neisser tried to present himself as the discoverer of the leprosy bacterium. However, Neisser’s first publication on Mycobacterium leprae refers explicitly to Hansen’s original discovery. How did the notion of Neisser trying to claim Hansen’s discovery emerge? A thorough source-critical examination of Hansen’s and Neisser’s scientific and popular publications between 1874 and 1897 as well as of the literature dealing with the so-called controversy brought interesting new results. The notion that Neisser tried to steal Hansen’s discovery is based on a misreading of Neisser’s publications by Hansen’s biographer. But Neisser tried indeed to bypass Hansen in trying to prove that Mycobacterium leprae was the contagion causing leprosy. The competition between the two scientists resulted in a personal enmity. This study shows how the history of modern science is prone to myths and underlines the importance of source criticism when dealing with established narratives.

Compost amendments are a promising tool for building productivity in degraded rangelands, but the effect on biological soil crusts (biocrusts), the surface microbial communities found in drylands, has not been investigated. Biocrusts contribute both carbon uptake and other ecosystem services in drylands. We investigated how 6.3 mm of surface-dressed compost at a Tribal rangeland in central New Mexico, USA, affected temperature, carbon and nitrogen characteristics, the relative abundance of biocrust microbial communities (fungi and bacteria) – specifically cyanobacterial communities – as well as the resulting aggregate stability at the soil surface after 1 year. Surface temperature maxima increased with compost addition in cooler ambient conditions, and the δ13C signatures of the soils from compost addition plots were >1‰ lighter compared to controls, indicating >35% of soil carbon was compost-derived, but organic C, total N percentage and aggregate stability did not differ among compost treatments. Several compost-derived taxa became indicator species in the amended plots, and compost addition decreased cyanobacteria relative abundance up to 58%. While previous results show that compost may benefit plants from a slow-release fertilization effect and soil carbon in deeper soil layers increases, there could be complex impacts on biocrust organic carbon with changing temperature and microbial community.

Objectives: Periprosthetic joint infection (PJI) is one of the most serious and debilitating complications that can occur after total joint arthroplasty. Therefore, early diagnosis and appropriate treatment are important for a good prognosis. Recently, molecular diagnostic methods have been widely used to detect the causative microorganisms of PJI sensitively and rapidly. The Multiplex Loop- Mediated Isothermal Amplification (LAMP) method is faster and easier to perform compared to polymerase chain reaction (PCR)-based assays. Therefore, this study developed a multiplex LAMP assay for diagnosing bacterial PJI using LAMP technology and evaluated its analytical and clinical performance. Methods: We developed a multiplex LAMP assay for the detection of five bacteria: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus agalactiae, Pseudomonas aeruginosa, and Escherichia coli, frequently observed to be the causative agents of PJI. The method limit of detection (LOD) and cross-reactivity were determined by spiking standard strains into the joint synovial fluid. The LOD of the multiplex LAMP assay was compared with that of a quantitative real-time PCR (qPCR) assay. Clinical performance was evaluated using 20 joint synovial fluid samples collected from patients suspected of having bacterial PJI. Results: The LOD of the gram-positive bacterial multiplex LAMP assay and qPCR were 105/104 CFU/mL, 103/103 CFU/mL, and 105/104 CFU/mL against S. agalactiae, S. epidermidis, and S. aureus, respectively. For P. aeruginosa and E. coli, the LOD of the multiplex LAMP and qPCR assays were 105/104 and 106/104 CFU/mL, respectively. The multiplex LAMP assay detects target bacteria without cross-reacting with other bacteria, and exhibited 100% sensitivity and specificity in clinical performance evaluation. Conclusions: This multiplex LAMP assay can rapidly detect five high-prevalence bacterial species causing bacterial PJI, with excellent sensitivity and specificity, in less than 1 h, and it may be useful for the early diagnosis of PJI.

Increasing disease outbreaks and declining biodiversity underscore the need for understanding the impact pathogens have on wildlife populations. To understand how zoonoses impact wild animal welfare, we created a severity index. Using signs of disease information from a bacterial zoonotic disease database, we quantified severity of each sign of disease combined with the number of welfare domains and body systems the pathogen impacts to find the severity index value (SIV) of each unique host-pathogen relationship. We then investigated the effects of host-pathogen richness and conservation status against SIV. We found there to be a strong, negative correlation between increasing pathogen richness and SIV. Species of least concern (LC) were not significantly more likely to have higher SIV than species of conservation concern (CC), but CC species did not have a significant decline of SIV with increasing pathogen richness. This study provides an insight into the relationships between pathogen richness and the risk of pathogen infections to wildlife.

Antarctic glaciers have been considered classically uninhabited. However, they constitute an authentic biome and are populated by microorganisms that not only survive in them but also maintain an active metabolism. The South Shetland archipelago is a good study model to observe the diversity and evolution of the microbial populations that inhabit its glaciers. From a geological point of view, this archipelago is of considerable interest due to the intense and relatively recent volcanic eruptions on Deception Island. Additionally, it has been a place of transit for human and animal populations over time. All of these factors have influenced the composition and diversity of the microbial communities inhabiting the glacial ice. Among these microorganisms, a great diversity of bacteria, archaea, viruses and microeukaryotes such as algae and unicellular fungi have been identified thanks to high-throughput technologies. These cold-adapted microorganisms develop molecular mechanisms of adaptation to the extreme environment they inhabit and contribute to global energy cycles through the processing of organic and inorganic compounds. This review summarizes current knowledge on the biodiversity, ecology and molecular mechanisms of adaptation of cold-adapted microorganisms, and it details the specific characteristics of the microbial populations housed in the Antarctic glaciers in the South Shetland archipelago.

This study evaluated the effects of dietary yeast culture (YC) supplementation on rumen microbiota and lactation performance in dairy goats. Twenty mid-lactation dairy goats were selected and divided into two groups: the control (CON) group was fed a basal diet; the YC group was supplemented with 10 g of YC in 1 kg of basal diet. The administration of YC was associated with a significant increase in dry matter intake, milk yield, milk protein yield, and milk lactose yield in dairy goats (P < 0.05). Additionally, serum total protein, albumin, creatinine, glucose, superoxide dismutase, and catalase levels were increased (P < 0.05). Furthermore, there was an increase in rumen pH and NH3-N levels (P < 0.05), while volatile fatty acid levels were observed to decrease (P < 0.05). The study found no significant difference in the α-diversity of bacteria and fungi between the YC and CON groups (P > 0.05). However, 15 bacterial genera and 13 fungal genera were upregulated (P < 0.05), while 4 bacterial genera and 11 fungal genera were downregulated (P < 0.05) in the YC group. The relative abundance of pathogenic fungi Dipodascus and Gibberella decreased (P < 0.05). Correlation analysis revealed that the bacterial genera were not significantly correlated with lactation performance (P > 0.05), whereas fungal genera Dipodascus and Gibberella were significantly (P < 0.05) correlated with lactation performance. In conclusion, the study demonstrated that YC can influence the rumen microbial composition, reduce the abundance of harmful fungi in the rumen, and improve lactation performance in dairy goats, suggesting that the addition of YC to dairy goat diets has good application prospects.

Egg masses of Aplysia depilans consist of long and intertwined strings containing numerous capsules with eggs. Light microscopy stains and transmission electron microscopy revealed four layers in the gelatinous sheath that encircled and aggregated the chain of egg capsules. The outermost layer has a fluffy structure. The second, third, and fourth layers consisted of reticulated matrices with different densities. The second and third layers were divided into 5‒6 strata each. The fourth and innermost layer of the gelatinous sheath has a higher density and no visible stratification. This layer glues the tightly packed capsules to one another and to the outer layers of the gelatinous sheath. The thin wall of the capsules is formed by a homogeneous and highly electron-dense material. Inside the capsules, the eggs or embryos were bathed in an electron-lucent aqueous medium. Bacteria and diatoms were the most abundant microorganisms on the surface of egg strings. Bacteria penetrate the gelatinous sheath and appear to be involved in the degradation of the upper strata, but were never found inside the egg capsules. Metagenomic analysis revealed a large taxonomic diversity of bacteria associated with egg masses of A. depilans. Although 15 phyla could be recognized, the families Flavobacteriaceae (Bacteroidota), Lentisphaeraceae (Lentisphaerota), and Rhodobacteraceae (Pseudomonadota) represented 67.9% ± 11.6% of the relative abundance in the microbiome of the egg string samples. The presence of genera capable of decomposing polysaccharides, such as Tenacibaculum and Cellulophaga, supports the idea that bacteria are responsible for the degradation of the gelatinous layers of the egg strings.

Serogroup epidemiology of invasive meningococcal disease (IMD) is constantly evolving, varying by time and location. Surveillance reports have indicated a rise in meningococcal serogroup Y (MenY) in some regions in recent years. This systematic literature review explores the evolving epidemiology of MenY IMD globally based on review of recent articles and national surveillance reports published between 1 January 2010 and 25 March 2021. Generally, MenY incidence was low (<0.2/100,000) across all ages in most countries. The reported incidence was more frequent among infants, adolescents, and those aged ≥65 years. More than 10% of all IMD cases were MenY in some locations and time periods. Implementation of vaccination evolved over time as the rise in MenY IMD percentage occurred. Cases decreased in countries with quadrivalent vaccine programs (e.g., United Kingdom, the Netherlands, United States, and Australia), whereas the MenY burden increased and made up a large proportion of cases in areas without vaccine programs. Continuous monitoring of epidemiologic changes of IMD is essential to establish MenY burden and for implementation of prevention strategies.

In this comprehensive review, Acidithiobacillus ferrooxidans, an acidophilic bacterium, has been thoroughly examined as a plausible analogue for microbial life in Venus's lower cloud layer. Given its ability to adapt to extreme conditions, including low pH environments and metal-rich settings, Acidithiobacillus ferrooxidans is considered a promising candidate for studying life analogues in Venus's clouds. This article comprehensively analyses the bacterium's distinctive phenotypic and genotypic features, investigating its metabolic pathways, adaptive strategies and potential ecological niche within Venusian cloud ecosystems. After careful consideration of the environmental parameters characterizing Venus, the unidentified UV absorber in its clouds, and the prospects for microbial life, this review underscores the imperative nature of future Venus missions and the pivotal role that Acidithiobacillus ferrooxidans may play in exploring the possible habitability of Venus and advancing astrobiological research.

Iodine (I) is a trace element with health and environmental significance. Iodate (IO3-), iodide (I-) and organic iodine (org-I) are the major species of iodine that exist in the environment. Dissimilatory IO3--reducing bacteria reduce IO3- to I- directly under anoxic conditions via their IO3- reductases that include periplasmic iodate reductase IdrABP1P2, extracellular DMSO reductase DmsEFAB and metal reductase MtrCAB. IdrAB and DmsEFAB reduce IO3- to hypoiodous acid (HIO) and H2O2. The reaction intermediate HIO is proposed to be disproportionated abiotically into I- and IO3- at a ratio of 2:1. The H2O2 is reduced to H2O by IdrP1P2 and MtrCAB as a detoxification mechanism. Additionally, dissimilatory Fe(III)- and sulfate-reducing bacteria reduce IO3- to I- directly via their IO3- reductases and indirectly via the reduction products Fe(II) and sulfide in the presence of Fe(III) and sulfate, respectively. I--oxidizing bacteria oxidize I- to molecular iodine (I2) directly under oxic conditions via their extracellular multicopper iodide oxidases IoxAC. In addition to I2, a variety of org-I compounds are also produced by the I--oxidizing bacteria during I- oxidation. Furthermore, ammonia-oxidizing bacteria oxidize I- to IO3- directly under oxic conditions, probably via their intracellular ammonia-oxidizing enzymes. Many bacteria produce extracellular reactive oxygen species that can oxidize I- to triiodide (I3-). Bacteria also accumulate I- during which I- is oxidized to HIO by their extracellular vanadium iodoperoxidases. The HIO is then transported into the bacterial cells. Finally, bacteria methylate I- to org-I CH3I, probably via their methyltransferases. Thus, bacteria play crucial and versatile roles in the global biogeochemical cycling of iodine via IO3- reduction, I- oxidation and accumulation and org-I formation.

In the present study, we assessed the sponge fauna, sponge-associated, and planktonic prokaryotic communities residing in Burgers' Zoo Ocean aquarium, Arnhem, the Netherlands. The Ocean aquarium consisted of separate displays and life support systems, and included fish-only systems in addition to a large, 750,000 L tank containing a living, tropical coral reef ecosystem. Sponges were observed throughout the aquarium system and were identified as belonging to the genera Chalinula, Chondrilla, Chondrosia, Cinachyrella, Stylissa, Suberites and Tethya. There was a highly significant difference in composition between sponge-associated and planktonic prokaryotic communities. The tanks in which the sponges were sampled appeared to have a secondary structural effect on prokaryotic composition with sponges and water from the same tanks sharing several microorganisms. Both sponge-associated and planktonic prokaryotic communities housed prokaryotic taxa, which were highly similar to microorganisms previously recorded in sponges or coral reef environments, including taxa potentially involved in nitrification, denitrification, sulphur oxidation, and antibiotic biosynthesis. Several abundant microorganisms were only recorded in sponges and these may play a role in maintaining water quality in the aquarium system. Potential pathogens, e.g. related to Photobacterium damselae, and beneficial organisms, e.g. related to Pseudovibrio denitrificans, were also detected. The present study showed that Burgers' Zoo Ocean aquarium housed diverse free-living and host-associated prokaryotic communities. Future research should focus on identifying conditions and microbial communities conducive to a healthy aquarium environment.