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Veterinary Medicine and Science May 2024Companion animals, including dogs and cats, are frequently identified as sources of Pasteurella multocida, a bacterium that can be transmitted to humans and cause...
BACKGROUND
Companion animals, including dogs and cats, are frequently identified as sources of Pasteurella multocida, a bacterium that can be transmitted to humans and cause infections.
OBJECTIVES
This survey defines the prevalence, antibiotic sensitivity, capsular types, lipopolysaccharide (LPS) types and virulence factors of P. multocida isolated from cats.
METHODS
A total of 100 specimens from various cat breeds were collected. P. multocida was characterized using both biochemical tests and PCR. Genotypes of isolates were determined using capsular and LPS typing methods. Additionally, virulotyping was performed by detecting the presence of 12 virulence-associated genes. Disk diffusion was used to determine the antibiotic sensitivity of the isolates.
RESULTS
The prevalence of P. multocida in cats was 29%. Among the isolates, the majority were capsular type A (96.5%) and type D (3.4%), with a predominant presence of type A. Twenty-six of the isolates (89.66%) belonged to LPS genotype L6, whereas three isolates (10.3%) belonged to genotype L3. Among the 12 virulence genes examined, sodC, oma87, ptfA, nanB and ompH showed remarkable prevalence (100%). The toxA gene was detected in four isolates (13.8%). Variations were observed in other virulence genes. The nanH gene was present in 93.1% of the isolates, whereas the pfhA gene was detected in 58.6% of the isolates. The exbD-tonB, hgbB, sodA and hgbA genes showed prevalence rates of 96.5%, 96.5%, 96.5% and 82.8%, respectively. Additionally, particular capsule and LPS types were associated with specific virulence genes. Specifically, the toxA and pfhA genes were found to be more prevalent in isolates with capsular type A and LPS genotype L6. Most isolates were resistant to ampicillin, clindamycin, lincomycin, streptomycin and penicillin.
CONCLUSIONS
According to this epidemiological and molecular data, P. multocida from cats possess several virulence-associated genes and are resistant to antimicrobial medicines commonly used in humans and animals. Thus, it is crucial to consider the public health concerns of P. multocida in humans.
Topics: Cats; Animals; Humans; Dogs; Pasteurella multocida; Pasteurella Infections; Anti-Bacterial Agents; Lipopolysaccharides; Cat Diseases; Dog Diseases
PubMed: 38519838
DOI: 10.1002/vms3.1424 -
Cureus Feb 2024Background Invasive meningococcal disease (IMD) is a bacterial infection caused by Neisseria meningitidis, which primarily affects the meninges, with a high incidence in...
Background Invasive meningococcal disease (IMD) is a bacterial infection caused by Neisseria meningitidis, which primarily affects the meninges, with a high incidence in young children. The most effective technique for preventing IMD is vaccination, which has been available for over 40 years through meningococcal polysaccharide capsule-containing vaccines. This study aims to assess the parental knowledge of meningococcal disease and vaccination in the Makkah region of Saudi Arabia. Methodology A cross-sectional study was conducted between September and December 2023 among 597 parents in the Makkah region using a validated online survey. The collected data were analyzed using the Statistical Package for the Social Sciences (SPSS). Results The study sample included 597 parents, of which 339 (56.8%) were female and 258 (43.2%) were male. Our research demonstrated that 388 (65%) participants had an insufficient understanding of IMD, while 209 (35%) had a sufficient understanding. There was a significant correlation between the knowledge score and the completion of the routine vaccination and whether vaccinating a child is essential for the protection of other members of society. Conclusions Based on our study, only around one-third of the participants demonstrated a sufficient level of knowledge regarding IMD and its vaccination. To provide a more accurate assessment of the Saudi population, additional research should be conducted in various regions and cities.
PubMed: 38510876
DOI: 10.7759/cureus.54450 -
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 -
Microbiology Spectrum Apr 2024Capsular polysaccharides (CPS) in are pivotal for bacterial virulence and present extensive diversity. While oral streptococci show pronounced antigenicity toward...
UNLABELLED
Capsular polysaccharides (CPS) in are pivotal for bacterial virulence and present extensive diversity. While oral streptococci show pronounced antigenicity toward pneumococcal capsule-specific sera, insights into evolution of capsule diversity remain limited. This study reports a pneumococcal CPS-like genetic locus in , a predominant oral . The discovered locus comprises 15 genes, mirroring high similarity to those from the Wzy-dependent CPS locus of . Notably, elicited a reaction with pneumococcal 19B antiserum. Through nuclear magnetic resonance analysis, we ascertained that its CPS structure matches the chemical composition of the pneumococcal 19B capsule. By introducing the glucosyltransferase gene from a pneumococcal serotype 19C, we successfully transformed antigenicity from 19B to 19C. Furthermore, substituting serotype-specific genes, and , with their counterparts from pneumococcal serotype 19A and 19F enabled to generate 19A- and 19F-specific CPS, respectively. These findings underscore that harbors a versatile 19B-like CPS adaptable to other serotypes. Remarkably, after deleting the locus's initial gene, , responsible for sugar transfer, we noted halted CPS production, elongated bacterial chains, and diminished biofilm formation. A similar phenotype emerged with the removal of the distinct gene , which encodes a putative autolysin. These data highlight the importance of CPS for biofilm formation and propose a potential shared ancestry of its CPS locus with .
IMPORTANCE
Diverse capsules from are vital for bacterial virulence and pathogenesis. Oral streptococci show strong responses to a wide range of pneumococcal capsule-specific sera. Yet, the evolution of this capsule diversity in relation to microbe-host interactions remains underexplored. Our research delves into the connection between commensal oral streptococcal and pneumococcal capsules, highlighting the potential for gene transfer and evolution of various capsule types. Understanding the genetic and evolutionary factors that drive capsule diversity in and its related oral species is essential for the development of effective pneumococcal vaccines. The present findings provide fresh perspectives on the cross-reactivity between commensal streptococci and , its influence on bacteria-host interactions, and the development of new strategies to manage and prevent pneumococcal illnesses by targeting and modulating commensal streptococci.
Topics: Streptococcus pneumoniae; Streptococcus; Polysaccharides; Serogroup; Pneumococcal Vaccines; Genetic Engineering; Bacterial Capsules; Polysaccharides, Bacterial
PubMed: 38488366
DOI: 10.1128/spectrum.01885-23 -
NPJ Biofilms and Microbiomes Mar 2024In environments characterized by extended multi-stress conditions, pathogens develop a variety of immune escape mechanisms to enhance their ability to infect the host.... (Review)
Review
In environments characterized by extended multi-stress conditions, pathogens develop a variety of immune escape mechanisms to enhance their ability to infect the host. The capsules, polymers that bacteria secrete near their cell wall, participates in numerous bacterial life processes and plays a crucial role in resisting host immune attacks and adapting to their niche. Here, we discuss the relationship between capsules and bacterial virulence, summarizing the molecular mechanisms of capsular regulation and pathogenesis to provide new insights into the research on the pathogenesis of pathogenic bacteria.
Topics: Bacterial Capsules; Virulence; Bacteria
PubMed: 38480745
DOI: 10.1038/s41522-024-00497-6 -
Biological Research Mar 2024The convergence of hypervirulence and carbapenem resistance in the bacterial pathogen Klebsiella pneumoniae represents a critical global health concern. Hypervirulent K....
BACKGROUND
The convergence of hypervirulence and carbapenem resistance in the bacterial pathogen Klebsiella pneumoniae represents a critical global health concern. Hypervirulent K. pneumoniae (hvKp) strains, frequently from sequence type 23 (ST23) and having a K1 capsule, have been associated with severe community-acquired invasive infections. Although hvKp were initially restricted to Southeast Asia and primarily antibiotic-sensitive, carbapenem-resistant hvKp infections are reported worldwide. Here, within the carbapenemase production Enterobacterales surveillance system headed by the Chilean Public Health Institute, we describe the isolation in Chile of a high-risk ST23 dual-carbapenemase-producing hvKp strain, which carbapenemase genes are encoded in a single conjugative plasmid.
RESULTS
Phenotypic and molecular tests of this strain revealed an extensive resistance to at least 15 antibiotic classes and the production of KPC-2 and VIM-1 carbapenemases. Unexpectedly, this isolate lacked hypermucoviscosity, challenging this commonly used hvKp identification criteria. Complete genome sequencing and analysis confirmed the K1 capsular type, the KpVP-1 virulence plasmid, and the GIE492 and ICEKp10 genomic islands carrying virulence factors strongly associated with hvKp. Although this isolate belonged to the globally disseminated hvKp clonal group CG23-I, it is unique, as it formed a clade apart from a previously reported Chilean ST23 hvKp isolate and acquired an IncN KPC-2 plasmid highly disseminated in South America (absent in other hvKp genomes), but now including a class-I integron carrying bla and other resistance genes. Notably, this isolate was able to conjugate the double carbapenemase plasmid to an E. coli recipient, conferring resistance to 1st -5th generation cephalosporins (including combinations with beta-lactamase inhibitors), penicillins, monobactams, and carbapenems.
CONCLUSIONS
We reported the isolation in Chile of high-risk carbapenem-resistant hvKp carrying a highly transmissible conjugative plasmid encoding KPC-2 and VIM-1 carbapenemases, conferring resistance to most beta-lactams. Furthermore, the lack of hypermucoviscosity argues against this trait as a reliable hvKp marker. These findings highlight the rapid evolution towards multi-drug resistance of hvKp in Chile and globally, as well as the importance of conjugative plasmids and other mobile genetic elements in this convergence. In this regard, genomic approaches provide valuable support to monitor and obtain essential information on these priority pathogens and mobile elements.
Topics: Humans; Klebsiella pneumoniae; Chile; Escherichia coli; Klebsiella Infections; Plasmids; Anti-Bacterial Agents; Carbapenems; Bacterial Proteins; beta-Lactamases
PubMed: 38475927
DOI: 10.1186/s40659-024-00485-2 -
International Journal of Molecular... Mar 2024Enteropathogenic (EPEC) produce a capsule of polysaccharides identical to those composing the O-antigen polysaccharide of its LPS (lipopolysaccharide) molecules. In...
Enteropathogenic (EPEC) produce a capsule of polysaccharides identical to those composing the O-antigen polysaccharide of its LPS (lipopolysaccharide) molecules. In light of this, the impact of O26 polysaccharides on the immune evasion mechanisms of capsulated O26 EPEC compared to non-capsulated enterohemorrhagic (EHEC) was investigated. Our findings reveal that there was no significant difference between the levels in EPEC and EHEC of rhamnose (2.8:2.5), a molecule considered to be a PAMP (Pathogen Associated Molecular Patterns). However, the levels of glucose (10:1.69), heptose (3.6:0.89) and N-acetylglucosamine (4.5:2.10), were significantly higher in EPEC than EHEC, respectively. It was also observed that the presence of a capsule in EPEC inhibited the deposition of C3b on the bacterial surface and protected the pathogen against lysis by the complement system. In addition, the presence of a capsule also protected EPEC against phagocytosis by macrophages. However, the immune evasion provided by the capsule was overcome in the presence of anti-O26 polysaccharide antibodies, and additionally, these antibodies were able to inhibit O26 EPEC adhesion to human epithelial cells. Finally, the results indicate that O26 polysaccharides can generate an effective humoral immune response, making them promising antigens for the development of a vaccine against capsulated O26
Topics: Humans; Enteropathogenic Escherichia coli; Immune Evasion; Enterohemorrhagic Escherichia coli; Escherichia coli Infections; Escherichia coli Proteins; Lipopolysaccharides; Vaccine Development
PubMed: 38474124
DOI: 10.3390/ijms25052878 -
MBio Apr 2024(), a Gram-positive bacterium, is responsible for causing a wide variety of invasive infections. The emergence of multi-drug antibiotic resistance has prompted the...
UNLABELLED
(), a Gram-positive bacterium, is responsible for causing a wide variety of invasive infections. The emergence of multi-drug antibiotic resistance has prompted the search for antimicrobial alternatives. Phage-derived peptidoglycan hydrolases, known as endolysins, are an attractive alternative. In this study, an endolysin active against , designated SP-CHAP, was cloned, produced, purified, biochemically characterized, and evaluated for its antimicrobial properties. Cysteine, histidine-dependent amidohydrolase/peptidase (CHAP) domains are widely represented in bacteriophage endolysins but have never previously been reported for pneumococcal endolysins. Here, we characterize the first pneumococcal endolysin with a CHAP catalytic domain. SP-CHAP was antimicrobial against all serovars tested, including capsular and capsule-free pneumococci, and it was found to be more active than the most widely studied pneumococcal endolysin, Cpl-1, while not affecting various oral or nasal commensal organisms tested. SP-CHAP was also effective in eradicating biofilms at concentrations as low as 1.56 µg/mL. In addition, a mouse nasopharyngeal colonization model was employed, which showed that SP-CHAP caused a significant reduction in colony-forming units, even more than Cpl-1. These results indicate that SP-CHAP may represent a promising alternative to combating infections.
IMPORTANCE
Considering the high rates of pneumococcal resistance reported for several antibiotics, alternatives are urgently needed. In the present study, we report a -targeting endolysin with even greater activity than Cpl-1, the most characterized pneumococcal endolysin to date. We have employed a combination of biochemical and microbiological assays to assess the stability and lytic potential of SP-CHAP and demonstrate its efficacy on pneumococcal biofilms and in an mouse model of colonization. Our findings highlight the therapeutic potential of SP-CHAP as an antibiotic alternative to treat infections.
Topics: Animals; Mice; Peptide Hydrolases; Streptococcus pneumoniae; Cysteine; Histidine; Amidohydrolases; Endopeptidases; Anti-Bacterial Agents; Pneumococcal Infections; Bacteriophages; Biofilms
PubMed: 38470268
DOI: 10.1128/mbio.00069-24 -
Scientific Reports Mar 2024Here, we conducted a comprehensive analysis of 356 Klebsiella pneumoniae species complex (KpSC) isolates that were classified as classical (cl), presumptive...
Here, we conducted a comprehensive analysis of 356 Klebsiella pneumoniae species complex (KpSC) isolates that were classified as classical (cl), presumptive hypervirulent (p-hv) and hypermucoviscous-like (hmv-like). Overall, K. pneumoniae (82.3%), K. variicola (2.5%) and K. quasipneumoniae (2.5%) were identified. These isolates comprised 321 cl-KpSC, 7 p-hv-KpSC and 18 hmv-like-KpSC. A large proportion of cl-KpSC isolates were extended-spectrum-β-lactamases (ESBLs)-producers (64.4%) and 3.4% of isolates were colistin-resistant carrying carbapenemase and ESBL genes. All p-hv-KpSC showed an antibiotic susceptible phenotype and hmv-like isolates were found to be ESBL-producers (8/18). Assays for capsule production and capsule-dependent virulence phenotypes and whole-genome sequencing (WGS) were performed in a subset of isolates. Capsule amount differed in all p-hv strains and hmv-like produced higher capsule amounts than cl strains; these variations had important implications in phagocytosis and virulence. Murine sepsis model showed that most cl strains were nonlethal and the hmv-like caused 100% mortality with 3 × 10 CFUs. Unexpectedly, 3/7 (42.9%) of p-hv strains required 10 CFUs to cause 100% mortality (atypical hypervirulent), and 4/7 (57.1%) strains were considered truly hypervirulent (hv). Genomic analyses confirmed the diverse population, including isolates belonging to hv clonal groups (CG) CG23, CG86, CG380 and CG25 (this corresponded to the ST3999 a novel hv clone) and MDR clones such as CG258 and CG147 (ST392) among others. We noted that the hmv-like and hv-ST3999 isolates showed a close phylogenetic relationship with cl-MDR K. pneumoniae. The information collected here is important to understand the evolution of clinically important phenotypes such as hypervirulent and ESBL-producing-hypermucoviscous-like amongst the KpSC in Mexican healthcare settings. Likewise, this study shows that mgrB inactivation is the main mechanism of colistin resistance in K. pneumoniae isolates from Mexico.
Topics: Animals; Mice; Klebsiella pneumoniae; Klebsiella; Colistin; Phylogeny; Klebsiella Infections; beta-Lactamases; Anti-Bacterial Agents; Phenotype; Microbial Sensitivity Tests
PubMed: 38467675
DOI: 10.1038/s41598-024-55546-z -
Nature Communications Mar 2024Bacterial evolution is affected by mobile genetic elements like phages and conjugative plasmids, offering new adaptive traits while incurring fitness costs. Their...
Bacterial evolution is affected by mobile genetic elements like phages and conjugative plasmids, offering new adaptive traits while incurring fitness costs. Their infection is affected by the bacterial capsule. Yet, its importance has been difficult to quantify because of the high diversity of confounding mechanisms in bacterial genomes such as anti-viral systems and surface receptor modifications. Swapping capsule loci between Klebsiella pneumoniae strains allowed us to quantify their impact on plasmid and phage infection independently of genetic background. Capsule swaps systematically invert phage susceptibility, revealing serotypes as key determinants of phage infection. Capsule types also influence conjugation efficiency in both donor and recipient cells, a mechanism shaped by capsule volume and conjugative pilus structure. Comparative genomics confirmed that more permissive serotypes in the lab correspond to the strains acquiring more conjugative plasmids in nature. The least capsule-sensitive pili (F-like) are the most frequent in the species' plasmids, and are the only ones associated with both antibiotic resistance and virulence factors, driving the convergence between virulence and antibiotics resistance in the population. These results show how traits of cellular envelopes define slow and fast lanes of infection by mobile genetic elements, with implications for population dynamics and horizontal gene transfer.
Topics: Phenotype; Plasmids; Serogroup; Genome, Bacterial; Bacteriophages
PubMed: 38448399
DOI: 10.1038/s41467-024-46147-5