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Purpose: To evaluate and compare bacterial growth on zirconia vs titanium healing caps. Materials and Methods: Streptococcus sanguinis (Ss) and Ftreptococcus nucleatum (Fn) were grown on titanium and zirconia healing caps that were fixed to the cover of a 96-well microtiter plate. A drop (10 µL) of bacterial suspension was placed on each healing cap and allowed to dry for 1 hour at 37°C. After this time, the cover was replaced on the plate such that the caps were completely immersed in fresh liquid medium. Each plate contained only one bacterial strain, with two control groups. Bacterial growth was monitored over 18 hours by following the optical density (OD) at 650 nm. One-way ANOVA comparison test was used for statistical analysis. Scanning electron microscope (SEM) images of healing caps of each material were taken after 48 hours of incubation with Ss or Fn to assess bacterial attachment and with no bacteria as a negative control. Results: Ss growth was similar in both types of healing cap, with no significant differences between these groups and the control (P = .990). However, there was significantly less growth of Fn on the zirconia caps than on the titanium samples (P < .0001) or the control (P < .0001). SEM imaging revealed obvious differences in the surface characteristics of the titanium and zirconia caps. The number of bacteria attached to the rough apical area was particularly high. Conclusions: The use of zirconia healing caps may reduce the growth of some bacterial species compared to that seen on titanium healing caps. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. This study aimed to investigate the interaction between Lactobacillus helveticus H9 (H9) and Bifidobacterium animalis ssp. lactis Probio-M8 (M8) through metabolomics analysis, focusing on understanding how co-culturing these strains can enhance bacterial growth and metabolism, thereby shortening the fermentation cycle and improving efficiency. The H9 and M8 strains were cultured individually and in combination (1:1 ratio) in milk. The fermented milk metabolomes were analyzed using solid-phase microextraction-gas chromatography-mass spectrometry. In the dual-strain fermentation, the M8 strain exhibited a 2.33-fold increase in viable bacterial count compared with single-strain fermentation. Additionally, the dual-strain fermentation resulted in greater metabolite abundance and diversity. Notably, the dual-strain fermented milk showed significantly elevated levels of metabolites, including 5-methyl-2-hexanone, (E)-3-octen-2-one, acetic acid, alanine, and 3-hydroxy-butanal. Our results demonstrated that co-culturing the M8 and H9 strains accelerated growth and fermentation efficiency. This enhancement effect is likely attributed to the strong proteolytic ability of the H9 strain, which hydrolyzes casein to produce small molecular peptides, alanine, tyrosine, and other growth-promoting factors. The insights gained from this study have significant implications for probiotics and the dairy industry, potentially leading to shorter fermentation cycles, enhanced cost-effectiveness, and improved nutritional and functional properties of future fermented milk products. Additionally, these findings may contribute to advancements in probiotic research and applications. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the impact of special ripening conditions on the cheese ripening process and the qualitative characteristics of the final product. The ripening chambers were specially designed to allow precise control of microclimatic conditions, including temperature, humidity, airflow, and most importantly, overpressure. Research methods included conducting microbiological analyses and Gas Chromatography/Mass Spectrometry (GC/MS) analysis of volatile components on cheese samples aged in a control and overpressure chamber over two months at 10-16 °C and 75-85 % relative humidity. The effect of ripening time (3.59-6.41 weeks, which is approximately 3 weeks and 4 days, and 6 weeks and 3 days, respectively) and overpressure (1.18- 3.31 mbar) was investigated by response surface methodology (RSM). The results showed that overpressure has successfully controlled bacterial and yeast growth during ripening time. Mould levels have shown different trends, with initial growth, followed by a decrease until the end of the ripening period. As for volatile compounds, the presence of 3,5 dihydroxydecanoic acid 1,5 lactone was found to be the most abundant aroma component found in cheese samples. It was concluded that the use of special ripening chambers with overpressure treatment could significantly enhance the microbial stability and aromatic profile of cheese, thereby improving its overall quality. [ABSTRACT FROM AUTHOR]

Riboflavin is an essential vitamin for humans and animals, with its annual demand experiencing a consistent upward trajectory. In recent years, newly constructed riboflavin producing strains are difficult to reach the level of industrial strains. Therefore, developing competitive strains is crucial for advancing the riboflavin industry. The expression level of the rib operon is strongly correlated with riboflavin biosynthesis. The strain S12, which overexpressed the rib operon of B. subtilis using plasmids with approximately 8 copies, achieved a 53.9 % increase in riboflavin biosynthesis during shake-flask fermentation. However, the strain cannot grow normally in a 7.5-L bioreactor. The expression of rib operon may have competed with cell growth for GTP or produced toxic intermediate ArP. Therefore, the strain S16 replaced ribA in rib operon with a monofunctional DHBP synthase, increased 20 % of riboflavicn production in a 7.5-L bioreactor. Furthermore, the strain S24, which overexpressed the rib operon using the phase-dependent promoter P yqgZ , attained a riboflavin production of 29 g/L in a 7.5-L bioreactor, achieving the highest reported riboflavin production to date. This study reports for the first time using the phase-dependent promoter for overexpression of rib operon, effectively regulated the relationship between cell growth and riboflavin production. [Display omitted] • The ribA in rib operon was replaced with a monofunctional DHBP synthase from a mutated ribA or a heterologous source. • The replacement solve the accumulation of toxic intermediate Arp, restore bacterial growth, enhance riboflavin production. • This study reports for the first time using the phase-dependent promoter for overexpression of rib operon. • The obtained strain effectively regulate growth and production, achieve a riboflavin yield of 29 g/L in a 7.5 L bioreactor. [ABSTRACT FROM AUTHOR]

The combined use of lytic bacteriophages with antibiotics is currently being explored as a strategy to enhance the effectiveness of infectious disease therapies, including those caused by Staphylococcus aureus. In this study, we investigated the synergistic potential of bacteriophage vB_SauM-515A1 (Herelleviridae family) and the first-line antibiotic linezolid against the methicillin-resistant S. aureus strain SA0413Rev. A checkerboard assay revealed a significant synergistic effect against planktonic cells (FIC = 0.225): a combination of 1/8 MIC of linezolid and 0.01 MOI of the bacteriophage completely inhibited bacterial growth. However, the impact on biofilm-associated cells depended on the treatment sequence. Sequential administration resulted in antagonism, while simultaneous application demonstrated a synergistic effect, as confirmed through scanning electron microscopy. Transcriptomic analysis of S. aureus SA0413Rev under the combined influence of linezolid (1/4 MIC) and bacteriophage vB_SauM-515A1 (10 MOI) predominantly reflected changes associated with productive bacteriophage infection, including alterations in nucleotide metabolism, activation of prophage regions, and virulence factors. Furthermore, both agents affected energy and carbon metabolism. These findings contribute to the development of combination therapy approaches for infections caused by S. aureus and highlight the importance of optimizing treatment conditions for maximal therapeutic efficacy. [ABSTRACT FROM AUTHOR]

Background: Lysosomal storage diseases (LSDs), a group of inborn errors of metabolism, include various subtypes, for example, mucopolysaccharidosis (MPS) and Gaucher disease (GD). Besides the physical/mental disabilities, they suffer from several oral deteriorations. Aim: To evaluate the oral health status of Egyptian children with LSD. Design: Thirty LSD children and thirty non‐LSD children were enrolled for this study according to the inclusion and exclusion criteria. Dental indices were used to assess caries prevalence and periodontal status. Saliva samples were collected from all enrolled children to estimate interleukin 6 (IL‐6), tumor necrosis factor‐α (TNF‐α), and protein levels as well as Streptococcus mutans and Lactobacilli colony counts. Results: Children with MPS and GD showed non‐significant differences in decayed, missing, or filled teeth (DMFT) scores (p =.115). Scores of dmft showed a significant increase in MPS, but not in GD children (p =.020, p =.127). Children with LSD showed significantly increased Modified Gingival Index (MGI), Plaque Index (PI), Oral Hygiene Index (OHI‐s) scores (p <.001) and salivary IL‐6 and TNF‐α (p =.007, p =.001, p <.0001, p =.002, respectively) and salivary total proteins (p =.001) levels. Unexpectedly, non‐significant differences were observed in salivary Streptococcus mutans or Lactobacilli counts in children with MPS and GD (p =.058, p =.420, p =.502, p =.053, respectively). Conclusion: To our knowledge, this is the first article that evaluates Egyptian children with LSD. We demonstrated high caries prevalence in primary teeth, not permanent teeth, in children with MPS and poor gingival/hygiene status in children with MPS and GD, which triggered a state of inflammation. The daily supplement intake prevented oral bacterial growth. The most probable cause of oral alterations is decreased salivary flow rate, as deduced from a significantly increased salivary protein. [ABSTRACT FROM AUTHOR]

The study aimed to evaluate the effects of multi-strain probiotic (MSP) on broiler growth, health, and nutrient utilization under high animal protein concentrate conditions. Male Ross-308 broilers were assigned to four groups: a control (C), MSP at 50 mg/kg (MSP50), MSP at 100 mg/kg (MSP100), and Zinc bacitracin (ZB) as a positive control. MSP supplementation significantly improved feed intake, weight gain, and feed conversion efficiency, with MSP100 demonstrating the best feed conversion ratio during both starter and finisher phases. MSP also enhanced dressing percentages and positively influenced blood lipid profiles. The supplementation reduced harmful bacterial growth (E. coli, Salmonella, Clostridium perfringens) while promoting beneficial bacteria (Lactobacillus). Moreover, MSP positively impacted gut histomorphology, showing higher villus height, width, and crypt depth in the MSP100 group. Digestibility of dry matter and crude protein was enhanced in birds fed the MSP100 diet. Overall, MSP supplementation exhibited positive effects on broiler performance, health, and nutrient digestibility, indicating its potential as an antibiotic alternative for improving practices in the poultry feed industry. [ABSTRACT FROM AUTHOR]

Background: Microorganisms in dental unit water (DUW) play a significant role in dental bioaerosols. If the methods used to decontaminate DUW also help improve air quality in dental clinics is worth exploring. In this study, we aim to identify the source of bacteria in dental bioaerosols and investigate the impact of waterline disinfectants on the quantity and composition of bacteria in DUW and bioaerosols. Methods: Two dental chair units in a separate treatment room are installed with two different waterline decontamination systems, a plasma or iodine cartridge. The experiment was performed in two phases, before and after installing the decontamination systems. Aerosol is generated via running airotor in the subject's mouth. Before and after the procedure, the air samples were collected with an active air sampling machine onto agar plate and filter paper for genomic DNA extraction. The subject's saliva and DUW samples were also collected. The samples were analyzed further with bacterial counting and metataxonomics analysis. Results: The bacteria present in the air sample after the aerosol-generating procedure were confirmed to be derived from the air-before, saliva, and DUW in 51.43%, 6.38%, and 18.60%, respectively. The saliva samples demonstrated the highest alpha diversity (within the sample), whereas the air samples had the least. Both waterline disinfectants effectively controlled bacteria in DUW but did not affect the bacterial number and composition in the air. Conclusions: Dental bioaerosols are composed of bacteria from saliva and DUW. Plasma and iodine showed a trend in controlling bacterial contamination in DUW but did not alter the bacterial count and composition in dental bioaerosols. [ABSTRACT FROM AUTHOR]

Tuberculosis remains a burden to this day, due to the rise of multi and extensively drug-resistant bacterial strains. The genome of Mycobacterium tuberculosis (Mtb) strain H37Rv underwent an annotation process that excluded small Open Reading Frames (smORFs), which encode a class of peptides and small proteins collectively known as microproteins. As a result, there is an overlooked part of its proteome that is a rich source of potentially essential, druggable molecular targets. Here, we employed our recently developed proteogenomics pipeline to identify novel microproteins encoded by non-canonical smORFs in the genome of Mtb using hundreds of mass spectrometry experiments in a large-scale approach. We found protein evidence for hundreds of unannotated microproteins and identified smORFs essential for bacterial survival and involved in bacterial growth and virulence. Moreover, many smORFs are co-expressed and share operons with a myriad of biologically relevant genes and play a role in antibiotic response. Together, our data presents a resource of unknown genes that play a role in the success of Mtb as a widespread pathogen. [ABSTRACT FROM AUTHOR]

Introduction: Platelet lysate (PL) demonstrates antimicrobial and anti-inflammatory properties offering potential for treatment of bacterial pneumonia in horses. It remains unknown whether nebulization is suitable for PL administration in horses. This pilot study characterized particle size and flow rate of pooled equine PL (single preparation) nebulized using an equine-specific nebulizer (Flexivent®). Methods: Protein composition and antimicrobial activity were compared before and after nebulization. Protein composition was evaluated according to growth factor, antimicrobial peptide and cytokine concentrations and proteomic analysis. To evaluate antimicrobial activity, bacterial growth inhibition [maximum growth (μmax); carrying capacity (K)] were determined for E. coli, Streptococcus equi subsp zooepidemicus and Rhodococcus equi (WT and MDR) using pre- and post-nebulized PL concentrations of 50%. Results: Flow rate and median particle size were 0.8 ml/min and 4.991 μm with 52% of particles ≤ 5 μm. Differences in PL protein composition were detected with nebulization. For E. coli and S. zooepidemicus , nebulization did not alter effect of PL on growth parameters. PL treatments decreased K for S. zooepidemicus (p = 0.009) compared to BHI. For R. equi K was increased post- vs. pre-nebulization (WT and MDR) and μmax increased pre- vs, post-nebulization (MDR). PL treatments increased K and μmax for MDR R. equi and μmax for WT R. equi compared to BHI (p ≤ 0.05). Conclusion: Nebulization of PL in vitro is technically feasible. The results of this study support further investigation to better characterize the effect of nebulization on PL and its suitability for nebulization in horses. [ABSTRACT FROM AUTHOR]

A complex interplay of genetic and environmental factors influences bacterial growth. Understanding these interactions is crucial for insights into complex living systems. This study employs a data-driven approach to uncover the principles governing bacterial growth changes due to genetic and environmental variation. A pilot survey is conducted across 115 Escherichia coli strains and 135 synthetic media comprising 45 chemicals, generating 13,944 growth profiles. Machine learning analyzes this dataset to predict the chemicals' priorities for bacterial growth. The primary gene-chemical networks are structured hierarchically, with glucose playing a pivotal role. Offset in bacterial growth changes is frequently observed across 1,445,840 combinations of strains and media, with its magnitude correlating to individual alterations in strains or media. This counterbalance in the gene-chemical interplay is supposed to be a general feature beneficial for bacterial population growth. Genetic and environmental factors shaping bacterial growth are explored using profiles of E. coli. Machine learning revealed glucose-dependent gene-chemical hierarchies and negative epistasis, highlighting mechanisms that maintain growth homeostasis. [ABSTRACT FROM AUTHOR]

Background: When assessing the genotoxicity of substances containing probiotic candidates, such as lactic acid-producing bacteria, using the in vitro micronucleus test (MNT), bacterial growth in the test medium may reduce the pH of the medium. The low medium pH is known to induce cytotoxicity and false-positive results. In the TK6 cell system, it is difficult to completely remove the bacteria from the medium by washing post-treatment, leading to bacterial growth during the recovery period in the short-term treatment. In the present study, the low pH range yielding false positives in the TK6 cell MNT was investigated using media supplemented with acetic, lactic, or formic acids, which are non-genotoxic bacterial metabolites. Additionally, to suppress the bacterial growth during the recovery period using antibiotics, i.e., penicillin/streptomycin (P/S), gentamicin sulfate (GM), and amphotericin B (AP), the maximum applicable concentrations of them that did not affect TK6 cell growth or micronucleus induction were determined. Then, we conducted an MNT using a substance containing live lactic acid-producing bacteria to verify the effectiveness of the antibiotics. Results: Acetic, lactic, and formic acids induced micronuclei in TK6 cells (false positive) at an initial pH of ≤ 6.2 and ≤ 6.0 in 3 h treatment with and without S9 mix, respectively, and of ≤ 6.7 in the continuous treatment. Media supplemented with P/S, GM, and AP did not affect TK6 cell growth or micronucleated cell frequencies in the negative and positive controls ≤ 400 unit/mL-400 µg/mL, ≤ 250, and ≤ 20 µg/mL, respectively. In an MNT with fermented milk containing live lactic acid-producing bacteria, supplementation with P/S or GM to media for the recovery cultures suppressed the bacterial growth, decreasing pH, and cytotoxicity. Conclusion: This study revealed the low pH ranges yielding false positives in the TK6 cell MNT under short-term and continuous treatment conditions. These values will serve as references for interpreting the biological relevance of results. Under short-term treatment, optimal antibiotic supplementation in recovery cultures suppressed bacterial growth in the test substance and prevented the decrease in pH that could yield false positives. This approach might be useful for evaluating the genotoxicity of test substances containing probiotic candidates using the MNT. [ABSTRACT FROM AUTHOR]

Mineral dissolution by bacteria is thought to depend on mineral properties, solution chemistry, and the carbon sources metabolized. To investigate whether mineral particle size could impact the effectiveness of weathering and the molecular mechanisms employed by bacteria, the strain Caballeronia mineralivorans PML1(12) was considered. Through microcosm and kinetic experiments, we quantified changes in biotite dissolution, bacterial growth, siderophore biosynthesis, and acidification. The use of different solution chemistries, carbon sources, and particle sizes (from <20 to 500 µm) allowed us to decipher the relative role of acidification- and chelation-driven mineral weathering by bacteria. Results revealed a faster dissolution for smaller particles (<100 µm) that strongly affected both solution chemistry and bacterial physiology, while larger particles (>100 µm) showed a slower and steady dissolution with minimal impact on bacterial processes. These findings underscore the influence and feedback effects of particle size on the dynamics of dissolution and the mechanisms employed by bacteria. [ABSTRACT FROM AUTHOR]

In nature, organisms experience combinations of stressors. However, laboratory studies use batch cultures, which simplify reality and focus on population-level responses to individual stressors. 1,2,3,4,5 In recent years, bacterial stress responses have been examined with single-cell resolution using microfluidics. 6,7,8,9,10,11,12 Here, we use a microfluidic approach to simultaneously provide a physical stressor (shear flow) and a chemical stressor (H 2 O 2) to the human pathogen Pseudomonas aeruginosa. By treating cells with levels of flow and H 2 O 2 that commonly co-occur in human host tissues, 13,14,15,16,17,18 we discover that previous reports significantly overestimate the H 2 O 2 levels required to block bacterial growth. Specifically, we establish that flow increases H 2 O 2 effectiveness 50-fold, explaining why previous studies lacking flow required much higher concentrations. Using natural H 2 O 2 levels, we identify the core H 2 O 2 regulon, characterize OxyR-mediated dynamic regulation, and demonstrate that multiple H 2 O 2 scavenging systems have redundant roles. By examining single-cell behavior, we serendipitously discover that the combined effects of H 2 O 2 and flow block pilus-driven surface migration. Thus, our results counter previous studies and reveal that natural levels of H 2 O 2 and flow synergize to restrict bacterial motility and survival. By studying two stressors at once, our research highlights the limitations of oversimplifying nature and demonstrates that physical and chemical stress can combine to yield unpredictable effects. [Display omitted] • Shear flow and H 2 O 2 combine to block bacterial migration and growth • Natural levels of H 2 O 2 trigger a small, clearly defined regulon • Shear flow enhances H 2 O 2 effectiveness by replenishing H 2 O 2 Here, Sharma et al. use microfluidics to simultaneously provide a physical stressor (shear flow) and a chemical stressor (H 2 O 2) to the human pathogen Pseudomonas aeruginosa. The replenishing power of shear flow increases H 2 O 2 effectiveness 50-fold, allowing natural levels of H 2 O 2 to block bacterial migration and growth. [ABSTRACT FROM AUTHOR]

Infections caused by Gram‐negative bacteria present a significant risk to human health worldwide. Novel strategies are needed to deal with the challenge caused by drug‐resistant bacteria. Here, we report a new approach to combat infections by targeting iron‐binding proteins to suppress bacterial growth. We investigated the function of the conserved periplasmic binding protein FecB from Vibrio alginolyticus. FecB was known to play a crucial role in the bacterial growth and to relate with biofilm formation. We then solved the crystal structures and elucidated the binding mechanism of FecB with ferric ion chelated by citrate. The results indicated that FecB binds weakly to one citrate molecule and strongly to the Fe3+‐(citrate)2 complex. Based on these results, a structure‐based virtual screening approach was conducted against FecB to identify small molecules that block ferric citrate uptake. Further evaluations in vivo and in vitro demonstrated that salvianolic acid C significantly suppressed bacterial growth, indicating that targeting bacterial nutrient absorption is a promising strategy for identifying potential antibacterial drugs. [ABSTRACT FROM AUTHOR]

New Delhi metallo‐β‐lactamase‐1 (NDM‐1)‐producing bacteria are resistant to nearly all available β‐lactam antibiotics and have become a public health threat. Antibiotic resistance often carries fitness costs, which typically manifest as a reduced bacterial growth rate. Here, we investigated the mechanism of fitness cost in NDM‐1‐producing bacteria. Our findings revealed that strains expressing blaNDM‐1 exhibited a significant growth defect under high osmotic stress. This fitness cost was attributed to the anchoring of NDM‐1 to the bacterial outer membrane via its leader peptide, which destabilized the outer membrane. Replacing the membrane‐anchoring residue Cys26 in the leader peptide with alanine not only restored outer membrane stability but also ameliorated the bacterial fitness cost. Furthermore, the anchoring of NDM‐1 to the membrane increased bacterial susceptibility to the membrane‐disrupting antibiotic colistin, both in vitro and in vivo, as confirmed in engineered and clinically isolated strains. In conclusion, membrane anchoring of NDM‐1 increased the permeability of the bacterial outer membrane, thereby reducing the fitness of NDM‐1‐producing bacteria and enhancing their susceptibility to colistin. These results not only elucidate the mechanism of fitness cost associated with NDM‐1 but also provide new insights into the rational use of colistin to combat infections caused by NDM‐1‐producing bacteria. [ABSTRACT FROM AUTHOR]

Objective Animals Studied Procedures Results Conclusion This retrospective study evaluates the efficacy of povidone‐iodine (PI) and polyhexamethylene biguanide (PHMB) as preoperative antiseptics in equine ophthalmic procedures.Horses that underwent routine ophthalmic surgery and procedures.Data were collected retrospectively from the medical records of equine patients undergoing ophthalmic procedures. Inclusion criteria were sampling for aerobic microbial culture at three different time points (T0: pre‐irrigation, T1: post‐irrigation, and T2: postoperatively) and T0 showing bacterial growth. Microbiological outcomes were assessed semi‐quantitatively by creating a scoring system to describe the bacterial load. Furthermore, the species detected were evaluated. Poisson regression analysis was performed to evaluate the efficacy of the disinfectants.Eighty eyes (75 horses) met the inclusion criteria, with 36 cases being aseptically prepared with PI and 44 with PHMB. Both antiseptics significantly reduced the bacterial load and number of bacterial species (p < .001) between time points T0 and T1, and T0 and T2. PHMB showed a reduction in the bacterial load by 64% (CI: 51%–73%) whereas PI reduced it by 48% (CI: 36%–58%) between time points T0 and T1. The reduction in the number of bacterial species between time points T0 to T1 was significantly greater in the PHMB group (85%, CI: 70%–93%), compared to PI (47%, CI: 26%–62%).Both PHMB and PI reduced the bacterial load and number of species on the ocular surface and eyelids significantly, with 0.1% PHMB being superior to 0.2% PI. Therefore, PHMB can be considered as a good alternative in preoperative antisepsis in equine ophthalmic procedures. [ABSTRACT FROM AUTHOR]

The significant economic losses caused by S. abortus equi in donkey husbandry have increased interest in exploring the potential of phages and their enzymes as control strategies. In this study, a S. abortus equi phage, designated 4FS1, was isolated from sewage at a donkey farm. Transmission electron microscopy (TEM) revealed a typical icosahedral head and a long, non-contractile tail. It exhibited a short latent period of 20 min and a burst size of 160 plaque-forming units (PFU) per cell. It demonstrated a broad host range, infecting 36 out of 60 salmonella strains, with an optimal multiplicity of infection (MOI) of 0.01 for S. abortus equi S1. The phage titer remained stable at 109 PFU/mL between 37°C and 50°C and exceeded 108 PFU/mL at pH from 5.0 to 10.0. After 1 h of UV exposure, the titer remained at 107 PFU/mL and showed no significant variation across NaCl concentrations from 2.5 to 15%. The genome of phage 4FS1 consists of a 42,485 bp linear double-stranded DNA molecule with a G + C content of 49.07%. Of the 56 predicted open reading frames (ORFs), 32 were functional annotated, with no virulence or drug resistance genes identified. ORF36 was predicted to encode a depolymerase responsible for endorhamnosidase activity. Recombinant expression of the Dpo36 protein in prokaryotes significantly reduced biofilm formation and removal. Combined with healthy donkey serum, Dpo36 inhibited bacterial growth in vitro and enhanced the survival rates of mice infected with S. abortus equi. These findings highlight the promising potential of phages and their depolymerases as novel therapeutic agents against S. abortus equi. [ABSTRACT FROM AUTHOR]

Ribosomally synthesized and posttranslationally modified peptides (RiPPs) are a structurally diverse group of natural products that bacteria employ in their survival strategies. Herein, we characterized the structure, the biosynthetic pathway, and the mode of action of a RiPP family called bufferins. With thousands of homologous biosynthetic gene clusters throughout the bacterial phylogenetic tree, bufferins form by far the largest family of RiPPs modified by multinuclear nonheme iron-dependent oxidases (MNIO, DUF692 family). Using Caulobacter vibrioides bufferins as a model, we showed that the conserved Cys residues of their precursors are transformed into 5-thiooxazoles, further expanding the reaction range of MNIO enzymes. This rare modification is installed in conjunction with a partner protein of the DUF2063 family. Bufferin precursors are rare examples of bacterial RiPPs found to feature an N-terminal Sec signal peptide allowing them to be exported by the ubiquitous Sec pathway. We reveal that bufferins are involved in copper homeostasis, and their metal-binding propensity requires the thiooxazole heterocycles. Bufferins enhance bacterial growth under copper stress by complexing excess metal ions. Our study thus describes a large family of RiPP metallophores and unveils a widespread but overlooked metal homeostasis mechanism in bacteria. [ABSTRACT FROM AUTHOR]

Background: In diagnosing chronic orthopedic implant infections culture of sonicate represents a supplement to tissue cultures. However, the extent to which biofilm forms on implant surfaces and the degree of dislodgement of bacteria by sonication remains unclear. In this in vivo study using a low bacterial inoculum, we aimed to determine whether a variable effect of sonication could be observed in a standardized in vivo model. Materials and Methods: Seven Wistar rats underwent surgery with intramuscular implantation of two bone xenograft implants, each containing two steel plates. The grafts were inoculated with approximately 500 colony forming units (CFU) of Staphylococcus epidermidis ATCC 35984. After 20 days the rats were sacrificed, and the steel plates were removed from the bone grafts. Epifluorescence microscopy and scanning electron microscopy (SEM) were used to visualize biofilm formation and dislodgement on the plate surfaces. In addition to cultures of sonicate, a quantitative S. epidermidis specific PCR was developed for enumeration of bacteria. Results: A chronic, low-grade implant infection was successfully established, with all animals remaining in good health. All infected bone graft implants yielded abundant growth of S. epidermidis, with a median of 3.25 (1.6–4.6) × 10⁷ CFU per/graft. We were unable to distinguish infected plates from negative controls using epifluorescence microscopy. On infected plates small colonies of staphylococci were identified by SEM. The number of bacteria detected in the sonicate was low with 500 (100–2400) CFU/plate and 475 (140–1821) copies/plate by qPCR. The difference in area covered by fluorescent material before and after sonication was 10.1 (5.7–12.3) %, p = 0.018. Conclusion: Despite the pronounced infection in the surrounding tissue, only few bacteria were detected on the surface of the steel implants. This is evident from the minimal findings by SEM before sonication, as well as the very low CFU counts and DNA copies in the sonicate. Sonication did not show variable effectiveness, indicating it is a valuable addition to, but not a replacement for biopsy cultures in cases of implant-associated infections with low-virulence microorganisms. [ABSTRACT FROM AUTHOR]

We observed multiple gray bats (Myotis grisescens) in 2022 with large patches of fur loss (i.e., alopecia) on the dorsal surface of their body. Alopecia in wildlife has been linked to multiple possible factors and often is a sign of suboptimal health. In 2023, we designed an experiment to compare prevalence of alopecia in gray bats across various reproductive stages, characterize the severity of alopecia lesions, and determine the ectoparasites and microbiota present on the regions of fur loss. We harp-trapped four summer gray bat roosts 2–3 times between 11 April–30 August 2023 and collected skin swabs and scrapes from each bat with alopecia. We determined the severity of the alopecia lesions on a scale 0–7 by summing the degree of redness (0–2), skin condition (0–1), and percentage of fur loss (0–4). We cultured the skin swabs for fungal and bacterial growth and examined skin scrapes under a microscope to determine the presence of subcutaneous mites. We found no evidence that subcutaneous mites cause the fur loss. We determined that prevalence of alopecia in M. grisescens varies throughout the summer. Prevalence is highest for female bats that are or recently were lactating, reaching an average of 6% ± 6 SD (0–15% range) of captured females exhibiting fur loss during the pup rearing period. Alopecia is most prevalent in male bats in early summer (1% ± 2 SD; 0–4% range). Lactating females had more severe cases than males and were often associated with skin redness due to unknown causes. Bats with alopecia did not differ in body condition, determined from body mass, from bats without alopecia. Future studies could investigate the role of stress in possible autoimmune responses contributing to alopecia. Conservation strategies aimed at reducing stress and supporting nutritional requirements during the summer are likely beneficial to M. grisescens. [ABSTRACT FROM AUTHOR]

Polyproline sequences are deleterious to cells because they stall ribosomes. In bacteria, EF-P plays an important role in overcoming such polyproline sequence-induced ribosome stalling. Additionally, numerous bacteria possess an EF-P paralog called EfpL (also known as YeiP) of unknown function. Here, we functionally and structurally characterize EfpL from Escherichia coli and demonstrate its role in the translational stress response. Through ribosome profiling, we analyze the EfpL arrest motif spectrum and find additional sequences beyond the canonical polyproline motifs that both EF-P and EfpL can resolve. Notably, the two factors can also induce pauses. We further report that EfpL can sense the metabolic state of the cell via lysine acylation. Overall, our work characterizes the role of EfpL in ribosome rescue at proline-containing sequences, and provides evidence that co-occurrence of EF-P and EfpL is an evolutionary driver for higher bacterial growth rates. EF-P plays an important role in overcoming polyproline sequence-induced stalling in bacteria. Here, the authors show that its paralog, EfpL, can also resolve this type of stalling, and also sense cellular metabolic states via lysine acylation. [ABSTRACT FROM AUTHOR]

Introduction: Streptococcus suis serotype (cps) 2 is an important bacterial pathogen in piglet nurseries and an emerging zoonotic agent without effective vaccines available. Immunoglobulin (Ig)M plays an essential role in host defense against S. suis. In mice, non-conventional B-1 cells are a major source of protective IgM against encapsulated bacterial pathogens, such as S. pneumoniae. Two IgM+CD21− B-1-like cell subpopulations, distinguishable by CD11R1 expression, were described in pigs, but their properties and functions are poorly understood. This study aimed at a first characterization of the porcine early IgM B cell response against S. suis cps 2. Methods: We analyzed the same healthy pigs, naturally colonized by different S. suis serotypes, including cps 2, at four and eight weeks of age serologically and determined the frequency of different peripheral B cell subpopulations by flow cytometry. Furthermore, we isolated conventional IgM+CD21+ B-2 cells as well as non-conventional B-1-like cell subpopulations from peripheral blood of eight-weeks-old pigs to evaluate their potential of IgM secretion in response to innate and adaptive stimuli in vitro. Results: Between the fourth and eighth week of life, a characteristic increase of S. suis cps 2-binding serum IgM antibodies, restricting bacterial growth, was observed. Moreover, we show for the first time that the significant increase of anti- S. suis serum IgM is associated with a relative increase of peripheral non-conventional IgM+CD21− B-1-like cells in vivo , particularly of the IgM+CD21− CD11R1− subpopulation. Noteworthy, sorted IgM+CD21− CD11R1− B-1-like cells from eight-weeks-old pigs spontaneously secreted IgM in vitro. In addition, both non-conventional IgM+CD21− B cell subpopulations, in contrast to conventional IgM+CD21+ B-2 cells, produced anti- S. suis IgM upon toll-like receptor (TLR) stimulation underlining their innate-like characteristics. We furthermore observed that both B-1-like subpopulations secrete S. suis cps 2-binding IgM upon stimulation with T cell-associated factors with highest amounts in IgM+CD21−CD11R1− B-1-like cells even exceeding anti- S. suis IgM levels produced by B-2 cells. Conclusion: Porcine non-conventional B-1-like cells are a potent source of S. suis -binding IgM indicating a role in immunity during a critical phase of piglet rearing. [ABSTRACT FROM AUTHOR]

This study investigated the antibacterial and anti-biofilm properties of postbiotics derived from Lactobacillus plantarum and their effect on the expression of antibiotic resistance genes (ermB and blaKPC) in Enterococcus faecalis and Pseudomonas aeruginosa , respectively. Cell-free supernatants (CFSs) were analyzed through gas chromatography–mass spectrometry (GC-MS), which showed that butyric acid (14.31%) was the major compound, other metabolites present in CFSs included lactic acid (5.94%), hdroxyacetone (5,21%), benzoic acid (3.12%), Pyrrolo[1,2-a] pyrazine-1,4-dione (1.91%), 2,3-Butanediol (1.04%), and 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (0.73.%). To investigate the effect of postbiotics on bacterial growth and biofilm formation, minimal inhibitory concentration (MIC) and microtiter plate assays were used. MIC results showed that resistant En. faecalis and P. aeruginosa can grow at concentrations of 2.5 and 5 mg/ml, respectively, after exposure to postbiotics. Furthermore, the microtiter plate results showed that postbiotics significantly reduced biofilm formation: 51%, 45%, and 39% in En. faecalis and 46%, 38%, and 27% in P. aeruginosa at different concentrations. Real-time polymerase chain reaction also confirmed the reduction of resistance genes (ermB; P  = 0.007 and blaKPC; P  = 0.02) expression. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay showed that the cell survival rate was 80%. These findings suggest that postbiotics from L. plantarum may be a promising approach for combating bacterial growth, biofilm formation, and antibiotic resistance. [ABSTRACT FROM AUTHOR]

Non-tuberculous mycobacteria (NTM) represent a diverse group of mycobacterial species known for causing opportunistic infections, especially in individuals with underlying health conditions. Unlike Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, NTM species exhibit different pathogenic characteristics and drug resistance mechanisms, making them increasingly relevant in clinical settings. PtkA is a crucial protein tyrosine kinase that regulates bacterial growth, stress response, and virulence by phosphorylating various substrates in Mtb. Understanding whether PtkA homologs exist in NTM could provide insights into their virulence and resistance mechanisms. In silico approaches, which utilize computational tools for sequence alignment, structure prediction, and functional annotation, offer a powerful means to identify homologous proteins across different species. In this article, we have employed tools like BLAST (Basic Local Alignment Search Tool), protein structure databases, and the NTM database to identify PtkA homologs in NTM genomes, providing a foundation for further studies. [ABSTRACT FROM AUTHOR]

This research investigated the inhibition of *Escherichia coli* ATCC 25922 (E. coli) bacterial growth in situ, specifically on the stems and aerial parts of *Agastache mexicana* subsp. mexicana (Amm) or "purple toronjil" and on food-grade paper, both contained within Kraft paper bags with a plastic window. The qualitative phytochemical profile of an aqueous extract of Amm revealed the presence of various compounds including alkaloids, coumarins, tannins, flavonoids, saponins, triterpenes, and sterols. The results indicate that these secondary metabolites exhibit a synergistic bactericidal effect, especially when combined with temperature and starvation stress. This was quantified using a decay equation referred to as the bacterial growth inhibition profile of E. coli (BGIPEc). Calculations, which included first derivatives, gradients based on substrate effects and temperature as well as the area under the curve of BGIPEc, demonstrated that higher temperatures led to the greater inhibition of colony forming units (CFUs), further enhanced by the presence of secondary metabolites. Additionally, a shorter half-life corresponded to a faster change rate and a lower area under the curve, indicating a reduced survival rate over time. At lower temperatures, E. coli exhibited a survival effect, which was corroborated by the preceding calculations. [ABSTRACT FROM AUTHOR]

Backgrounds/Objectives: Skin wound healing is a physiological process orchestrated by epithelial and mesenchymal cells able to restore tissue continuity by re-organizing themselves and the ECM. This research study aimed to develop an optimized in vitro experimental model of full-thickness skin, to address molecular and morphological modifications occurring in the re-epithelization and wound healing process. Methods: Wound healing starting events were investigated within an experimental window of 8 days at the molecular level by gene expression and immunofluorescence of key epidermal and dermal biomarkers. To mirror the behavior of infected wounds, the established wound healing model was then colonized with S. aureus, and the efficacy of a novel antibacterial agent, XZ.700, was investigated. Viable counts (CFU/tissue), IF, and ultrastructural analysis (SEM) were performed to evaluate S. aureus colonization inside and around the wound bed in an experimental window of 3 h of colonization and 24 h of treatment. Results: Endolysin showed an efficacy in counteracting bacterial growth and invasion within the wound bed, reducing the S. aureus load compared to its placebo, thanks to its selective antimicrobial activity interfering with biofilm formation. Conclusions: The preclinical in vitro infected wound model on FT-kin showed interesting applications to assess the repair efficacy of dermo-pharmaceutical and cosmetic formulations. [ABSTRACT FROM AUTHOR]

The control of 'sheath blight' in rice (Oryza sativa L.), which is caused by the fungus Rhizoctonia oryzae-sativae, has become problematic due to the excessive application of fungicides and their consequent harmful effects. Hence, the search for less contaminating alternatives to conventional chemical products is necessary. This study evaluated the in vitro inhibitory activity of four bacterial strains on the growth of R. oryzae-sativae in both tryptone soy broth (TSB) and mineral medium (MM). The results demonstrated that all evaluated strains (Bacillus tequilensis SMNCT17-02, Priestia aryabhattai SMNCH17-07, Burkholderia vietnamiensis TUR04-01, and Burkholderia vietnamiensis TUR04-03) inhibited the growth of R. oryzae-sativae. Specifically, the activity of B. tequilensis SMNCT17-02 resulted in the smallest area of R. oryzae-sativae growth in both TSB medium (8.54 cm2) and MM (5.53 cm2), suggesting a notable antifungal effect. When evaluating the action of supernatants generated by the growth of the four bacterial strains in TSB and MM culture media, significant inhibition of R. oryzae-sativae growth was only observed for supernatants produced in MM. This inhibition was attributed to the presence of soluble secondary metabolites. These results offer new perspectives in biotechnology, suggesting the possibility of developing effective products based on easily extractable soluble secondary metabolites, thus promoting sustainable agriculture. [ABSTRACT FROM AUTHOR]

As natural predators of bacteria, tailed bacteriophages can be used in biocontrol applications, including antimicrobial therapy. Also, phage lysis is a detrimental factor in technological processes based on bacterial growth and metabolism. The spectrum of bacteria bacteriophages interact with is known as the host range. Phage science produced a vast amount of host range data. However, there has been no attempt to analyse these data from the viewpoint of modern phage and bacterial taxonomy. Here, we performed a meta-analysis of spotting and plaquing host range data obtained on strains of production host species. The main metric of our study was the host range value calculated as a ratio of lysed strains to the number of tested bacterial strains. We found no boundary between narrow and broad host ranges in tailed phages taken as a whole. Family-level groups of strictly lytic bacteriophages had significantly different median plaquing host range values in the range from 0.18 (Drexlerviridae) to 0.70 (Herelleviridae). In Escherichia coli phages, broad host ranges were associated with decreased efficiency of plating. Bacteriophage morphology, genome size, and the number of tRNA-coding genes in phage genomes did not correlate with host range values. From the perspective of bacterial species, median plaquing host ranges varied from 0.04 in bacteriophages infecting Acinetobacter baumannii to 0.73 in Staphylococcus aureus phages. Taken together, our results imply that taxonomy of bacteriophages and their bacterial hosts can be predictive of intraspecies host ranges. [ABSTRACT FROM AUTHOR]

Patients with end‐stage renal disease (ESRD) undergoing chronic hemodialysis are at an increased risk of developing spondylodiscitis, an infectious condition affecting the vertebral column. In this case report, we present a 22‐year‐old male with ESRD, a history of hyperoxaluria, nephrolithiasis, and anemia, who developed spondylodiscitis. Notably, pathological examination of tissue samples obtained during surgical intervention revealed the presence of polarized calcium oxalate crystals within the lumbar laminae and spinal discs, a rare finding in this clinical context. The deposition of these crystals may have contributed to the development and progression of spondylodiscitis by creating an environment conducive to bacterial growth and infection. This case highlights the importance of comprehensive pathological assessment in ESRD patients with spondylodiscitis, as it may uncover uncommon manifestations that could have implications for disease management. Further research is necessary to elucidate the underlying mechanisms of this rare presentation and its impact on the clinical course and treatment of spondylodiscitis in ESRD patients undergoing hemodialysis. [ABSTRACT FROM AUTHOR]

Despite their serious disadvantages, which include higher upfront costs, the possibility of malfunctions due to corrosiveness, and a negative impact on the organoleptic properties of the food and possibly its nutritional importance, conventional antibacterial techniques such as pasteurization, pressure preparation, and radioactive substances are also valid as synthetic antiseptics, in fact, reduce bacterial growth in food to varying degrees. Most importantly, these cleaning techniques remove all contaminants, including various (often helpful) microorganisms found naturally in food. One potential solution to some of these issues is bacteriophage bio-control, a common and inexpensive method that uses lytic bacteriophages taken from the environment to selectively target harmful bacteria and eliminate significantly reduce their stages of feeding. It has been claimed that using bacteriophages on food is a novel way to prevent the growth of germs in vegetables. This review highlights the role of bacteriophages in food safety and their advantages in detail. [ABSTRACT FROM AUTHOR]

Environmental abuses and subsequent array of health hazards by petroleum products have emerged as a global concern that warrants proper remediation. Pyrene (PYR), a polycyclic aromatic hydrocarbon, is a xenobiotic by-product during crude petroleum processing. Biodegradation potential of two bacterial isolates (MK4 and MK9) of Brevibacterium sediminis from oil contaminated sites was explored. MK4 and MK9 could degrade PYR up to 23 and 59% (1000 mg.L− 1), respectively. A first-order formalism with the rate constant for MK4 and MK9 were found to be 0.022 ± 0.001 and 0.081 ± 0.005 day− 1, respectively with the corresponding half life period of 31.4 ± 1.4 and 8.6 ± 0.60 days respectively. Both the isolates produce biosurfactants as established by drop collapse assay, oil spreading and emulsification activity studies. Decrease in pH, change in absorbance (bacterial growth), and catechol formation support adaptation capability of the isolates to degrade PYR by using it as a source of carbon. PYR ring cleavage was induced by the ring hydroxylating dioxogenase enzyme present in the strains, as identified by PCR assay. In silico analyses of the PYR degrading enzyme revealed its higher binding affinity (-7.6 kcal.mol− 1) and stability (Eigen value:1.655763 × 10− 04) to PYR, as further supported by other thoeroretical studies. MK9 strain was more efficient than the MK4 strain in PYR degradation. Studies gain its prominence as it reports for the first time on the aptitude of B. sediminis as novel PYR-degrading agent that can efficiently be used in the bioremediation of petroleum product pollution with a greener approach. [ABSTRACT FROM AUTHOR]

In response to the escalating crisis of antimicrobial resistance (AMR), there is an urgent need to research and develop novel antibiotics. This study presents the synthesis and assessment of innovative 4-aminoquinoline-benzohydrazide-based molecular hybrids bearing aryl aldehydes (HD1-23) and substituted isatin warheads (HS1-12), characterized using multispectroscopic techniques with high purity confirmed by HRMS. The compounds were evaluated against a panel of clinically relevant antibacterial strains including the Gram-positive Enterococcus faecium, Bacillus subtilis, and Staphylococcus aureus and a Gram-negative Pseudomonas aeruginosa bacterial strain. Preliminary screenings revealed that several test compounds had significant antimicrobial effects, with HD6 standing out as a promising compound. Additionally, HD6 demonstrated impressively low minimum inhibitory concentrations (MICs) in the range of (8–128 μg/mL) against the strains B. subtilis, S. aureus and P. aeruginosa. Upon further confirmation, HD6 not only showed bactericidal properties with low minimum bactericidal concentrations (MBCs) such as (8 μg/mL against B. subtilis) but also displayed a synergistic effect when combined with the standard drug ciprofloxacin (CIP), highlighted by its FICI value of (0.375) against P. aeruginosa, while posing low toxicity risk. Remarkably, HD6 also inhibited a multidrug-resistant (MDR) bacterial strain, marking it as a critical addition to our antimicrobial arsenal. Computation studies were performed to investigate the possible mechanism of action of the most potent hybrid HD6 on biofilm-causing protein (PDB ID: 7C7U). The findings suggested that HD6 exhibits favorable binding free energy, which is supported by the MD simulation studies, presumably responsible for the bacterial growth inhibition. Overall, this study provides a suitable core for further synthetic alterations for their optimization as an antibacterial agent. [ABSTRACT FROM AUTHOR]

Tigecycline is a last-resort antimicrobial in humans. Tetracyclines are the most widely used antimicrobials in livestock. Mobile tigecycline resistance genes [tet(X)] are disseminated worldwide, and tetracycline use may have promoted the selection of tet(X) genes. Thus, the selective pressure on tet(X) genes and their plasmids in livestock must be elucidated. We performed a retrospective study to clarify the prevalence of tigecycline-resistant Escherichia coli from pigs in Thailand. Screening for tigecycline resistance was performed on 107 E. coli strains from 25 samples, and tet(X)-carrying plasmids were characterized. tet(X) genes were cloned and expressed in E. coli. Bacterial growth rate in the presence of tetracycline as a result of the presence of tet(X) genes was also evaluated. Thirty-two tet(X4)-harboring tigecycline-resistant E. coli strains were detected in 10/25 samples (40%). The tet(X4) genes were carried on various Inc-type plasmids and flanked by ISCR2. The tet(X)-carrying plasmids were transferred to E. coli and Klebsiella pneumoniae. Acquisition of tet(X) genes and their plasmids improved bacterial growth in the presence of tetracycline. In summary, tetracycline use exerts selective pressure on tet(X) genes and their various backbone plasmids; therefore, a reduced amount of tetracycline use is important to limit the spreading of tet(X) genes. [ABSTRACT FROM AUTHOR]

Purpose: Although 5% povidone-iodine (PVP-I) is frequently used as an ocular antiseptic agent, there is a lack of consensus regarding the effects of PVP-I concentration, storage after opening, and compounded preparation on PVP-I antisepsis. We performed a series of in-vitro experiments to determine the impact of these factors on PVP-I's inhibition of common causes of post-procedural eye infection. Methods: Inhibition of microorganism growth was measured in-vitro as a function of active PVP-I exposure time. In control experiments, PVP-I was inactivated before microorganism exposure. Tested PVP-I solutions varied in concentration (0.6%, 5%, or 10%), length of storage after opening (0, 7, or 30 days), and preparation (commercial vs.compounded from stock PI solution). Tested pathogens included S. epidermidis, S. viridans, P. aeruginosa, methicillin-resistant S. aureus, methicillin-sensitive S. aureus, and C. albicans. Results: PVP-I solutions inhibited all bacterial growth by 3 min and fungal growth by 15 s. Compared to 5% PVP-I, the 0.6% PVP-I was less effective in inhibiting S. viridans growth (200 ± 0 colonies vs. 7 ± 8 at 30 s, P = 0.0004; 183 ± 21 vs. 0 ± 0 at 1 min, P = 0.018), but more effective in inhibiting P. aeruginosa (30 ± 20 vs. 200 ± 0 at 15 s, P = 0.019). Compared to commercial and newly-opened PVP-I solutions, compounded preparations and solutions stored for 7 or 30 days after bottle opening either preserved or improved antiseptic efficacy against tested microorganisms. Conclusions: Concentration of PVP-I solution affects antiseptic efficacy within 1 min of exposure, but all solutions performed equivalently at 3 min. In contrast to results of prior studies investigating dilute PVP-I, the 0.6% PVP-I did not demonstrate a uniformly equivalent or superior anti-septic effect. Compounded preparation and storage length after bottle opening did not decrease PVP-I antiseptic activity. [ABSTRACT FROM AUTHOR]

To evaluate bacterial growth in the bladder as a major virulence factor during urinary tract infections (UTIs), we assessed the variability of uropathogenic bacterial growth in urine samples over multiple timepoints from 3 postmenopausal women with no history of UTI. Following IRB approval, postmenopausal women who never had a UTI provided mid-stream urine samples 3 times daily (8 a.m., 12 p.m., and 4 p.m.), twice a week over 2 weeks, as well as dietary intake logs. Each sample was studied for pH and bacterial growth using 3 uropathogenic Escherichia coli (E.coli) strains (LRPF007, KE40, UTI89), 1 uropathogenic Enterococcus faecalis strain (HRH40), and 1 non-pathogenic E. coli strain (W3110). Similar mean growth yields were observed for the uropathogenic strains (mean ∆OD 600 = 0.1-0.13) with high variability (standard deviation [SD] = 0.12-0.28) and lower mean growth for the non-pathogenic strain (mean ∆OD 600 = 0.05). Urine from each individual at different collection times never had the same bacterial growth potential for any bacterial strain. There were significant associations between urine pH decrease with higher fat (P =.017), vitamin D (P =.02), magnesium (P =.049), fluid (P =.013), and ash (P =.01) intake. Major variations were observed in the bacterial growth response in the urine of the same individuals. These variations imply a requirement for a normalization procedure, eg, growth in synthetic urine, for analysis of bacterial growth in urine. There were significant associations between decreased urine pH and several nutrients found in foods that are classified as highly acidic. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To compare the antibacterial activities of different types of honey against common bacterial isolates cultured from wounds of dogs and cats. METHODS: 4 types of honey were used including a medical-grade manuka honey, a non-medical-grade manuka honey, a locally sourced non-medical-grade honey (non-MGH), and a commercially sourced non-MGH. Bacterial isolates were obtained from clinical wound cultures of dogs and cats including Staphylococcus pseudintermedius, Escherichia coli, Enterococcus faecalis, and Pseudomonas aeruginosa. The macro-broth dilution method was used to analyze the MIC and minimum bactericidal concentration. The percentage of growth inhibition was assessed for different types of honey at different concentrations using a generalized linear regression model. RESULTS: Medical-grade honey exhibited the lowest minimum bactericidal concentration against S pseudintermedius, E faecalis, and P aeruginosa, alongside the lowest MIC at 90% with statistically significant higher bacterial growth inhibition in medium and low concentrations. Non-medical-grade manuka honey had a similar bactericidal activity against S pseudintermedius and P aeruginosa compared to locally and commercially sourced non-MGH. CONCLUSIONS: In this in vitro study, MGH exhibited superior antibacterial activity against all bacterial isolates compared to other types of honey. CLINICAL RELEVANCE: Medical-grade honey displayed the greatest antibacterial activity against common wound pathogens and could be considered over other types of honey for wound management in cats and dogs. Locally and commercially sourced non-MGH appears to have a comparative efficacy against certain bacteria compared to non-medical-grade manuka honey and is more cost effective. Further in vivo studies are needed to confirm these findings. [ABSTRACT FROM AUTHOR]

Intrauterine Ureaplasma infection is associated with chorioamnionitis and preterm birth. The difficulty of detecting Ureaplasma species by conventional culture methods makes definitive diagnosis of clinical infection challenging. Thus far, quantitative tests for Ureaplasma have been performed using adult cervical samples, amniotic fluid, and pediatric bronchial secretions, but quantification of bacterial count in central nervous system infections caused by Ureaplasma species has not been unreported. We report a case of culture-negative Ureaplasma meningitis in a preterm infant in whom novel techniques to identify this pathogen and quantify bacterial count were effective. We suspected meningitis based on a sustained reduction in cerebrospinal fluid (CSF) glucose levels. Multiple CSF cultures were sterile. We confirmed infection by Ureaplasma species using the melting temperature mapping method. Treatment with erythromycin and ciprofloxacin resulted in a gradual decrease in the bacterial count in the CSF to 0. Our study highlights the potential utility of the melting temperature mapping method as a new diagnostic tool for culture-negative Ureaplasma meningitis and establishes the utility of serial quantification of bacterial count to monitor response to therapy. [ABSTRACT FROM AUTHOR]

Exopolysaccharides (EPSs) synthesized by probiotic bacteria have the potential to be used as food additives with health benefits. The goal of the present work was to investigate the production of EPSs by probiotic strains isolated from traditional dairy products in Kerman (Iran) and to characterize the produced EPS. The EPS production pattern was assessed by the pattern of bacterial growth as well as the effects of temperature and acidity changes on EPS production. To characterize the EPSs, FTIR spectroscopy was performed. The antibiofilm activity of the extracted EPS was evaluated by determining the pre- and post-adhesion treatments of EPS. Finally, the highest EPS-producing isolate was identified by molecular methods. Of the 15 selected isolates, the highest amount of EPS (0.53 g/L) was observed for the D-8 isolate. This isolate was identified as Enterococcus hirae strain D-8 by morphological, biochemical, and 16S rDNA gene sequencing analysis. The highest EPS production was observed at 30°C and pH 7.5 and started at the late logarithmic phase. FTIR analysis of the EPSs revealed diverse functional groups, including (O–H), (C–H), (C=O), and aldehyde groups. The results of this research showed that bacterial EPSs not only inhibited biofilm formation but also disrupted the established biofilms of some strains. These results highlight the importance of investigating strains that are able to produce EPS to deal with antibiotic resistance and biofilm disruption. [ABSTRACT FROM AUTHOR]

The vertebrate gut microbiota is a critical determinant of organismal function, yet whether and how gut microbial communities affect host fitness under natural conditions remains largely unclear. We characterised associations between a fitness proxy—individual growth rate—and bacterial gut microbiota diversity and composition in threespine stickleback fish introduced to large semi‐natural ponds. We detected a 63% higher richness of bacterial taxa (α‐diversity) in the guts of high‐fitness fish compared to low‐fitness fish, which might be driven by stronger bacterial dispersal among high‐fitness fish according to the fit of a neutral community model. Further, microbial communities of high‐fitness fish were more similar to one another (i.e., exhibited lower β‐diversity) than those of low‐fitness fish. The lower β‐diversity found to be associated with higher host fitness is consistent with the Anna Karenina principle—that there are fewer ways to have a functional microbiota than a dysfunctional microbiota. Our study links differences in α‐ and β‐diversity to a fitness‐related trait in a vertebrate species reared under naturalistic conditions and our findings provide a basis for functional tests of the fitness consequences of host‐microbiota interactions. [ABSTRACT FROM AUTHOR]

Summary: This work aimed to determine the total anthocyanin and phenolic contents and antioxidant capacity of extracts of the black rice's cold, hot and ultrasonic‐assisted extracts and their preservative effect on the storage quality of beef patties. The three extracts exhibited high anthocyanin, phenolic content and antioxidant capacity, and they were used in beef patties at five treatments (negative control without extract, positive control with 0.01% butylated hydroxytoluene (BHT), 7.5% cold extract, 7.5% hot extract and 7.5% ultrasound‐assisted extract). Raw and cooked beef patties were tested at 0, 3, 6, 9 and 12 days of cold storage in aerobically packaged polyethylene containers regarding pH, oxidative stability, antioxidant capacity and microbial quality. While adding black rice extracts did not influence the proximate composition of raw samples (P > 0.05), it slowed down the pH and lipid oxidation during storage and provided pH and thiobarbituric acid reactive substances (TBARS) stability in all final products. The BHT and treatments with extract indicated a higher 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) value than the negative control. Also, the incorporation of black rice extracts slightly retarded bacterial growth. These results suggest that the black rice extracts at 7.5% can be used effectively to protect beef patties from microbial spoilage and oxidation during cold storage for 12 days. [ABSTRACT FROM AUTHOR]

Biofilms are subjected to many environmental pressures that can influence community structure and physiology. In the oral cavity, and many other environments, biofilms are exposed to forces generated by fluid flow; however, our understanding of how oral biofilms respond to these forces remains limited. In this study, we developed a linear rocker model of fluid flow to study the impact of shear forces on Streptococcus gordonii and dental plaque‐derived multispecies biofilms. We observed that as shear forces increased, S. gordonii biofilm biomass decreased. Reduced biomass was largely independent of overall bacterial growth. Transcriptome analysis of S. gordonii biofilms exposed to moderate levels of shear stress uncovered numerous genes with differential expression under shear. We also evaluated an ex vivo plaque biofilm exposed to fluid shear forces. Like S. gordonii, the plaque biofilm displayed decreased biomass as shear forces increased. Examination of plaque community composition revealed decreased diversity and compositional changes in the plaque biofilm exposed to shear. These studies help to elucidate the impact of fluid shear on oral bacteria and may be extended to other bacterial biofilm systems. [ABSTRACT FROM AUTHOR]

Aquaculture faces significant challenges due to bacterial pathogens like Aeromonas hydrophila, which can severely impact production and fish health. Understanding the relationship between environmental factors, host susceptibility, and bacterial virulence is crucial for effectively managing and mitigating the risks associated with A. hydrophila in aquaculture systems. A. hydrophila, found ubiquitously in aquatic environments, possesses various virulence factors that enhance its pathogenicity. These factors are closely linked to environmental conditions, such as temperature and pH, which play pivotal roles in bacterial growth, survival, and pathogenic potential. Fluctuations in temperature and pH significantly influence A. hydrophila's metabolic activity and growth rate, thereby modulating its virulence and overall pathogenicity. Ammonia, a byproduct of aquatic organism metabolism and organic matter decomposition, can accumulate to toxic levels in aquaculture settings, compromising fish health and immune function. Elevated ammonia concentrations worsen A. hydrophila infections by compromising host immunity and creating favorable conditions for bacterial proliferation. Oxygen concentration, host signals, and diet formulation are significantly impacting the susceptibility of aquatic organisms to infection. These factors are the most crucial in shaping the ecology, physiology, and pathogenicity of A. hydrophila in aquaculture. There is limited information on how these environmental factors modulate the virulence genes of such important fish pathogens. The knowledge of A. hydrophila virulence and its interplay with environmental factors paves the way for developing strategies to prevent and control diseases in aquaculture. [ABSTRACT FROM AUTHOR]

Bacteria are key organisms in energy and nutrient cycles, and predicting the effects of temperature change on bacterial activity is important in assessing global change effects. A changing in situ temperature will affect the temperature adaptation of bacterial growth in lake water, both long term in response to global change, and short term in response to seasonal variations. The rate of adaptation may, however, depend on whether temperature is increasing or decreasing, since bacterial growth and turnover scale with temperature. Temperature adaptation was studied for winter (in situ temperature 2.5 °C) and summer communities (16.5 °C) from a temperate lake in Southern Sweden by exposing them to a temperature treatment gradient between 0 and 30 °C in ~ 5 °C increments. This resulted mainly in a temperature increase for the winter and a decrease for the summer community. Temperature adaptation of bacterial community growth was estimated as leucine incorporation using a temperature Sensitivity Index (SI, log growth at 35 °C/4 °C), where higher values indicate adaptation to higher temperatures. High treatment temperatures resulted in higher SI within days for the winter community, resulting in an expected level of community adaptation within 2 weeks. Adaptation for the summer community was also correlated to treatment temperature, but the rate of adaption was slower. Even after 5 weeks, the bacterial community had not fully adapted to the lowest temperature conditions. Thus, during periods of increasing temperature, the bacterial community will rapidly adapt to function optimally, while decreasing temperature may result in long periods of non-optimal functioning. [ABSTRACT FROM AUTHOR]

The encapsulation of bacteria in emulsion droplets offers various advantages over other conventional methods of encapsulation, such as improvements in bacterial viability, and may serve as microenvironments for bacterial growth. Nevertheless, changes in temperature may affect bacterial viability and droplet stability. In this study, the encapsulation of bacteria in single water-in-oil (W/O) and double water-in-oil-in-water (W1/O/W2) emulsions under cold storage and temperature-modulated release were investigated. The microencapsulation of bacteria in emulsion droplets was achieved by using a flow-focusing microfluidic device. Droplet stability was determined by measuring changes in droplet size and creaming behaviour at different temperatures. The thermal properties of the samples were determined by using differential scanning calorimetry, while the release of bacteria with changes in temperature was determined by measuring the colony form unit (CFU) of the released bacteria and conducting fluorescence microscopy. Higher bacterial viability was observed for encapsulated samples compared to free cells, indicating the ability of the emulsion system to improve bacterial viability during cold-temperature storage. The crystallisation temperature was lowered in the presence of bacteria, but the melting temperature was similar with or without bacteria. Storage in freezing temperatures of −20 °C and −80 °C led to extensive droplet destabilisation, with the immediate release of encapsulated bacteria upon thawing, where the temperature-modulated release of encapsulated bacteria was achieved. This study provides an overview of the potential application of emulsion droplets for bacterial encapsulation under cold-temperature storage and the controlled release of encapsulated bacteria mediated by changes in temperature, which is beneficial for various applications in industries such as food and pharmaceuticals. [ABSTRACT FROM AUTHOR]