-
Pathogens (Basel, Switzerland) Mar 2024Urinary tract infections occupy a special niche among diseases of infectious etiology. Many microorganisms associated with urinary tract infections, such as , spp., , ,...
Urinary tract infections occupy a special niche among diseases of infectious etiology. Many microorganisms associated with urinary tract infections, such as , spp., , , , , , spp., and spp., can form biofilms. The aim of this research was to study the effect of the enzyme L-lysine-Alpha-oxidase (LO) produced by the fungus on the biofilm formation process of microorganisms associated with urinary tract infections. Homogeneous LO showed a more pronounced effect than the culture liquid concentrate (cCL). When adding samples at the beginning of incubation, the maximum inhibition was observed in relation to 5960-cCL 86%, LO 95%; 1669-cCL 85%, LO 94%; 6392-cCL 83%, LO-98%; and 3057-cCL 70%, LO-82%. The minimum inhibition was found in spp. Scanning electron microscopy was carried out, and numerous morphological and structural changes were observed in the cells after culturing the bacterial cultures in a medium supplemented with homogeneous LO. For example, abnormal division was detected, manifesting as the appearance of joints in places where the bacteria diverge. Based on the results of this work, we can draw conclusions about the possibility of inhibiting microbial biofilm formation with the use of LO; especially significant inhibition was achieved when the enzyme was added at the beginning of incubation. Thus, LO can be a promising drug candidate for the treatment or prevention of infections associated with biofilm formation.
PubMed: 38535596
DOI: 10.3390/pathogens13030252 -
Carbohydrate Research Apr 2024Moraxella nonliquefaciens is a commensal of the human upper respiratory tract (URT) but on rare occasions is recovered in cases of ocular, septic and pulmonary...
Moraxella nonliquefaciens is a commensal of the human upper respiratory tract (URT) but on rare occasions is recovered in cases of ocular, septic and pulmonary infections. Hence there is interest in the pathogenic determinants of M. nonliquefaciens, of which outer membrane (OM) structures such as fimbriae and two capsular polysaccharide (CPS) structures, →3)-β-D-GalpNAc-(1→5)-β-Kdop-(2→ and →8)-α-NeuAc-(2→, have been reported in the literature. To further characterise its surface virulence factors, we isolated a novel CPS from M. nonliquefaciens type strain CCUG 348T. This structure was elucidated using NMR data obtained from CPS samples that were subjected to various degrees of mild acid hydrolysis. Together with GLC-MS data, the structure was resolved as a linear polymer composed of two GalfNAc residues consecutively added to Kdo, →3)-β-D-GalfNAc-(1→3)-α-D-GalfNAc-(1→5)-α-(8-OAc)Kdop-(2→. Supporting evidence for this material being CPS was drawn from the proposed CPS biosynthetic locus which encoded a potential GalfNAc transferase, a UDP-GalpNAc mutase for UDP-GalfNAc production and a putative CPS polymerase with predicted GalfNAc and Kdo transferase domains. This study describes a unique CPS composition reported in Moraxella spp. and offers genetic insights into the synthesis and expression of GalfNAc residues, which are rare in bacterial OM glycans.
Topics: Humans; Polysaccharides; Moraxella; Transferases; Uridine Diphosphate; Bacterial Capsules; Polysaccharides, Bacterial
PubMed: 38507941
DOI: 10.1016/j.carres.2024.109095 -
Frontiers in Public Health 2024This study aimed to investigate the epidemiological characteristics of common pathogens contributing to childhood lower respiratory tract infections (LRTIs) in Xiangtan...
OBJECTIVE
This study aimed to investigate the epidemiological characteristics of common pathogens contributing to childhood lower respiratory tract infections (LRTIs) in Xiangtan City, Hunan Province before and during the coronavirus disease 2019 (COVID-19) pandemic.
METHODS
A total of 11,891 enrolled patients, aged 1 month to 14 years, diagnosed with LRTIs and admitted to Xiangtan Central Hospital from January 2018 to December 2021 were retrospectively reviewed in this study. Specifically, the epidemiological characteristics of these pathogens before and during the COVID-19 pandemic were analyzed.
RESULTS
There was a significant decrease in the number of children hospitalized with LRTIs during the COVID-19 pandemic (2020-2021) compared to data from 2018 to 2019 (before the COVID-19 pandemic). Of these cases, 60.01% (7,136/11,891) were male and 39.99% (4,755/11,891) were female. 78.9% (9,381/11,891) cases occurred in children under 4 years of age. The average pathogen detection rate among 11,891 hospitalized LRTIs children was 62.19% (7,395/11,891), with the average pathogen detection rate of 60.33% (4,635/7,682) and 65.57% (2,670/4,209) before and during COVID-19 pandemic, respectively. The detection rates of adenovirus (ADV), (BP) and () decreased dramatically, while the detection rates of influenza viruses (IFV), parainfluenza viruses (PIV), respiratory syncytial virus (RSV), (), (), and () increased significantly during the COVID-19 pandemic. Overall, RSV, (MP), , and IFV were the major pathogens causing LRTIs in hospitalized children before and during the COVID-19 pandemic.
CONCLUSION
Public health interventions for COVID-19 prevention are beneficial to reduce the incidence of LRTIs in children by limiting the prevalence of ADV, MP, BP, and , but which have limited restrictive effects on other common LRTIs-associated pathogens. Collectively, the data in this study comprehensively investigated the effects of COVID-19 pandemic on the epidemiological characteristics of respiratory pathogens, which will be beneficial for improving early preventive measures.
Topics: Child; Humans; Male; Female; Child, Preschool; Child, Hospitalized; Retrospective Studies; Staphylococcus aureus; Pandemics; COVID-19; Respiratory Tract Infections; Respiratory Syncytial Viruses
PubMed: 38476493
DOI: 10.3389/fpubh.2024.1367614 -
Foods (Basel, Switzerland) Mar 2024To expound on the correlation between the microorganism communities and the formation of off-odour in Xuanwei ham, the microorganism communities and volatile compounds...
To expound on the correlation between the microorganism communities and the formation of off-odour in Xuanwei ham, the microorganism communities and volatile compounds were investigated in the biceps femoris (BF) and semimembranosus (SM) of Xuanwei ham with different quality grades (normal ham and spoiled ham). The single molecule real-time sequencing showed that differential bacteria and fungi were more varied in normal hams than in spoiled hams. Headspace solid-phase microextraction-gas chromatography (HS-SPME-GC-MS) results indicated that aldehydes and alcohols were significantly higher in spoiled hams than those in normal hams ( < 0.05). The off-odour of spoiled hams was dominated by ichthyic, malodourous, sweaty, putrid, sour, and unpleasant odours produced by compounds such as trimethylamine (SM: 13.05 μg/kg), hexanal (BF: 206.46 μg/kg), octanal (BF: 59.52 μg/kg), methanethiol (SM: 12.85 μg/kg), and valeric acid (BF: 15.08 μg/kg), which are positively correlated with , , , sp., , and . Furthermore, the physicochemical property and quality characteristics results showed that high moisture (BF: 56.32 g/100 g), pH (BF: 6.63), thiobarbituric acid reactive substances (TBARS) (SM: 1.98 MDA/kg), and low NaCl content (SM: 6.31%) were also responsible for the spoilage of hams with off-odour. This study provided a deep insight into the off-odour of Xuanwei ham from the perspective of microorganism communities and a theoretical basis for improving the flavour and overall quality of Xuanwei hams.
PubMed: 38472889
DOI: 10.3390/foods13050776 -
The Journal of Allergy and Clinical... Jun 2024The respiratory microbiome has been associated with the etiology and disease course of asthma.
BACKGROUND
The respiratory microbiome has been associated with the etiology and disease course of asthma.
OBJECTIVE
We sought to assess the nasopharyngeal microbiota in children with a severe asthma exacerbation and their associations with medication, air quality, and viral infection.
METHODS
A cross-sectional study was performed among children aged 2 to 18 years admitted to the medium care unit (MCU; n = 84) or intensive care unit (ICU; n = 78) with an asthma exacerbation. For case-control analyses, we matched all cases aged 2 to 6 years (n = 87) to controls in a 1:2 ratio. Controls were participants of either a prospective case-control study or a longitudinal birth cohort (n = 182). The nasopharyngeal microbiota was characterized by 16S-rRNA-gene sequencing.
RESULTS
Cases showed higher Shannon diversity index (ICU and MCU combined; P = .002) and a distinct microbial community composition when compared with controls (permutational multivariate ANOVA R = 1.9%; P < .001). We observed significantly higher abundance of Staphylococcus and "oral" taxa, including Neisseria, Veillonella, and Streptococcus spp. and a lower abundance of Dolosigranulum pigrum, Corynebacterium, and Moraxella spp. (MaAsLin2; q < 0.25) in cases versus controls. Furthermore, Neisseria abundance was associated with more severe disease (ICU vs MCU MaAslin2, P = .03; q = 0.30). Neisseria spp. abundance was also related with fine particulate matter exposure, whereas Haemophilus and Streptococcus abundances were related with recent inhaled corticosteroid use. We observed no correlations with viral infection.
CONCLUSIONS
Our results demonstrate that children admitted with asthma exacerbations harbor a microbiome characterized by overgrowth of Staphylococcus and "oral" microbes and an underrepresentation of beneficial niche-appropriate commensals. Several of these associations may be explained by (environmental or medical) exposures, although cause-consequence relationships remain unclear and require further investigations.
Topics: Humans; Asthma; Child; Child, Preschool; Male; Nasopharynx; Female; Microbiota; Adolescent; Cross-Sectional Studies; Case-Control Studies; RNA, Ribosomal, 16S; Disease Progression; Prospective Studies; Bacteria
PubMed: 38467291
DOI: 10.1016/j.jaci.2024.02.020 -
Frontiers in Epidemiology 2023COVID-19 has emerged as a highly contagious and debilitating disease caused by the SARS-CoV-2 virus and has claimed the lives of over 7.7 million people worldwide....
INTRODUCTION
COVID-19 has emerged as a highly contagious and debilitating disease caused by the SARS-CoV-2 virus and has claimed the lives of over 7.7 million people worldwide. Bacterial co-infections are one of many co-morbidities that have been suggested to impact the outcome of COVID-19 in patients. The goals of this study are to elucidate the presence of bacteria in the nasopharynx of SARS-CoV-2 positive and negative patients and to describe demographic categories that may be associated with the detection of these organisms during one of the initial waves of the COVID-19 pandemic.
METHODS
To this end, we investigated SARS-CoV-2 and bacterial co-detection from outpatient RT-PCR testing in Texas.
RESULTS
The results indicate that , , , , and were the most frequently detected bacteria in both SARS-CoV-2 positive and SARS-CoV-2 negative patients and that these bacteria were present in these two patient populations at similar proportions. We also detected in a significantly larger proportion of males relative to females and people under 65 years of age relative to those 65 and over. Finally, we observed that SARS-CoV-2 was more commonly detected in Hispanics compared to non-Hispanics; however, low disclosure rates make volunteer bias a concern when interpreting the effects of demographic variables.
DISCUSSION
This study describes the bacteria present in the nasopharynx of SARS-CoV-2 positive and negative patients, highlights associations between patient demographics and SARS-CoV-2 as well as bacterial co-detection. In addition, this study highlights RT-PCR based molecular testing as a tool to detect bacteria simultaneously when SARS-CoV-2 tests are performed.
PubMed: 38455907
DOI: 10.3389/fepid.2023.1274800 -
Medical Microbiology and Immunology Mar 2024Multidrug-resistant clinical isolates of Moraxella catarrhalis have emerged, increasing the demand for the identification of new treatment and prevention strategies. A...
Multidrug-resistant clinical isolates of Moraxella catarrhalis have emerged, increasing the demand for the identification of new treatment and prevention strategies. A thorough understanding of how M. catarrhalis can establish an infection and respond to different stressors encountered in the host is crucial for new drug-target identification. Formaldehyde is a highly cytotoxic compound that can be produced endogenously as a by-product of metabolism and exogenously from environmental sources. Pathways responsible for formaldehyde detoxification are thus essential and are found in all domains of life. The current work investigated the role of the system consisting of the S-hydroxymethyl alcohol dehydrogenase (AdhC), a Zn-dependent class III alcohol dehydrogenase, and the S-formyl glutathione hydrolase (FghA) in the formaldehyde detoxification process in M. catarrhalis. Bioinformatics showed that the components of the system are conserved across the species and are highly similar to those of Streptococcus pneumoniae, which share the same biological niche. Isogenic mutants were constructed to study the function of the system in M. catarrhalis. A single fghA knockout mutant did not confer sensitivity to formaldehyde, while the adhC-fghA double mutant is formaldehyde-sensitive. In addition, both mutants were significantly cleared in a murine pulmonary model of infection as compared to the wild type, demonstrating the system's importance for this pathogen's virulence. The respective phenotypes were reversed upon the genetic complementation of the mutants. To date, this is the first study investigating the role of the AdhC-FghA system in formaldehyde detoxification and pathogenesis of M. catarrhalis.
Topics: Animals; Mice; Moraxella catarrhalis; Streptococcus pneumoniae; Formaldehyde; Glutathione; Hydrolases
PubMed: 38448747
DOI: 10.1007/s00430-024-00785-0 -
Carbohydrate Polymers May 2024Published work has shown that glycoconjugate vaccines, based on truncated detoxified lipopolysaccharides from Moraxella catarrhalis attached through their reducing end...
Published work has shown that glycoconjugate vaccines, based on truncated detoxified lipopolysaccharides from Moraxella catarrhalis attached through their reducing end to a carrier protein, gave good protection for all three serotypes A, B, and C in mice immunisation experiments. The (from the non-reducing end) truncated LPS structures were obtained from bacterial glycosyl transferase knock-out mutants and contained the de-esterified Lipid A, two Kdo residues and five glucose moieties. This work describes the chemical synthesis of the same outer Moraxella LPS structures, spacer-equipped and further truncated from the reducing end, i.e., without the Lipid A part and containing four or five glucose moieties or four glucose moieties and one Kdo residue, and their subsequent conjugation to a carrier protein via a five‑carbon bifunctional spacer to form glycoconjugates. Immunisation experiments both in mice and rabbits of these gave a good antibody response, being 2-7 times that of pre-immune sera. However, the sera produced only recognized the immunizing glycan immunogens and failed to bind to native LPS or whole bacterial cells. Comparative molecular modelling of three alternative antigens shows that an additional (2 → 4)-linked Kdo residue, not present in the synthetic structures, has a significant impact on the shape and volume of the molecule, with implications for antigen binding and cross-reactivity.
Topics: Rabbits; Animals; Mice; Lipopolysaccharides; Moraxella catarrhalis; Lipid A; Antibodies, Bacterial; Glycoconjugates; Oligosaccharides; Glucose; Carrier Proteins
PubMed: 38431400
DOI: 10.1016/j.carbpol.2024.121928 -
American Journal of Veterinary Research May 2024To evaluate the prevalence of oral bacteria in the conjunctiva of brachycephalic and nonbrachycephalic dogs.
OBJECTIVE
To evaluate the prevalence of oral bacteria in the conjunctiva of brachycephalic and nonbrachycephalic dogs.
ANIMALS
12 brachycephalic (9.58 ± 3.55 years) and 12 nonbrachycephalic (8.33 ± 4.92 years) dogs without systemic disease, regardless of breed and sex, were included in the study, and half of the dogs in each group had periodontitis.
METHODS
This prospective study investigated clinical data including craniofacial ratio, ophthalmic examination results, and periodontal status of the included dogs. Bacterial samples were collected by swabbing the oral mucosa and conjunctival surfaces. The presence and quantity of bacteria were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, 16S rRNA sequencing analysis, and the 10-fold dilution method. Statistical analyses were performed to assess correlations and factors influencing the presence of oral bacteria in the conjunctiva.
RESULTS
The most common bacteria in the conjunctival flora in both groups were Micrococcus luteus, Corynebacterium spp, and Staphylococcus spp. The prevalence of oral bacteria on the conjunctival surface was 33%, with a significantly higher incidence in brachycephalic dogs (P = .027). Oral bacteria detected in the conjunctiva were predominantly Frederiksenia canicola, Neisseria spp, and Moraxella spp. Multiple regression analysis identified age, craniofacial ratio, and gingival index as factors influencing the presence of oral bacteria in the conjunctival flora.
CLINICAL RELEVANCE
Oral resident bacteria have often been isolated from severe infectious corneal ulcers. This study provided evidence that brachycephalic dogs may require dental prophylaxis to reduce their oral bacterial load and that the association of oral bacteria in ocular diseases should be considered.
Topics: Animals; Dogs; Conjunctiva; Female; Male; Dog Diseases; Prospective Studies; Craniosynostoses; RNA, Ribosomal, 16S; Mouth; Bacteria
PubMed: 38422613
DOI: 10.2460/ajvr.23.11.0260 -
Frontiers in Veterinary Science 2024It has been recognized that capripoxvirus infections have a strong cutaneous tropism with the manifestation of skin lesions in the form of nodules and scabs in the...
INTRODUCTION
It has been recognized that capripoxvirus infections have a strong cutaneous tropism with the manifestation of skin lesions in the form of nodules and scabs in the respective hosts, followed by necrosis and sloughing off. Considering that the skin microbiota is a complex community of commensal bacteria, fungi and viruses that are influenced by infections leading to pathological states, there is no evidence on how the skin microbiome is affected during capripoxvirus pathogenesis.
METHODS
In this study, shotgun metagenomic sequencing was used to investigate the microbiome in pox lesions from hosts infected with lumpy skin disease virus and sheep pox virus.
RESULTS
The analysis revealed a high degree of variability in bacterial community structures across affected skin samples, indicating the importance of specific commensal microorganisms colonizing individual hosts. The most common and abundant bacteria found in scab samples were , , and , irrespective of host. Bacterial reads belonging to the genera , , , and were identified.
DISCUSSION
This study is the first to investigate capripox virus-associated changes in the skin microbiome using whole-genome metagenomic profiling. The findings will provide a basis for further investigation into capripoxvirus pathogenesis. In addition, this study highlights the challenge of selecting an optimal bioinformatics approach for the analysis of metagenomic data in clinical and veterinary practice. For example, direct classification of reads using a kmer-based algorithm resulted in a significant number of systematic false positives, which may be attributed to the peculiarities of the algorithm and database selection. On the contrary, the process of assembly requires a large number of target reads from the symbiotic microbial community. In this work, the obtained sequencing data were processed by three different approaches, including direct classification of reads based on k-mers, mapping of reads to a marker gene database, and assembly and binning of metagenomic contigs. The advantages and disadvantages of these techniques and their practicality in veterinary settings are discussed in relation to the results obtained.
PubMed: 38420205
DOI: 10.3389/fvets.2024.1321202