RESUMO
Staphylococcus aureus infection and colonization in patients may be transmitted to healthcare providers and the environment and subsequently cause healthcare-associated infections in other patients. Pathogenic S. aureus strains produce virulence factors, such as Panton-Valentine Leukocidin (PVL), that contribute to the severity of infections and aid in their spread. The emergence of antimicrobial resistance (AMR) is additional concern with respect to S. aureus infection. In this study, the virulence genes and antibiotic resistance profiles of S. aureus were characterized from patients' clinical isolates, healthcare workers' (HCWs') nasal colonization screenings, and the environment at a tertiary healthcare hospital in Addis Ababa, Ethiopia. A total of 365 samples were collected from September 2021 to September 2022: 73 patients' clinical specimens, 202 colonization screenings from HCWs, and 90 hospital environment's swabs. Fifty-one (25.2%) HCW and 10/90 (11.1%) environment S. aureus isolates were identified. Among the 134 isolates, 10 (7.5%) were methicillin-resistant S. aureus (MRSA). Three (4.1%), five (9.8%), and two (20.0%) of the MRSA isolates were identified from the patients, HCWs, and the environment, respectively. Overall, 118 (88.1%) were ampicillin and penicillin resistant; 70 (52.2%) were trimethoprim sulfamethoxazole resistant; and 28 (20.9%) were erythromycin resistant. S. aureus isolates from patients were more resistant to antibiotics than isolates from HCWs or the hospital environment (p<0.05). A total of 92/134 (68.6%) isolates possessed the lukfF-PV gene, which was identified in 62 (85.0%), 26 (51.0%), and 4 (40.0%) of the patient, HCWs, and the environment, respectively. The proportion of lukfF-PV gene containing S. aureus isolated from patient samples was statistically significant. Four (40.0%) of the MRSA isolates also had the lukfF-PV gene. The identification of highly AMR and virulence factors from patients, HCWs and the environment is concerning. Further studies are needed to identify potential transmission links and improve infection prevention and control.
Assuntos
Antibacterianos , Pessoal de Saúde , Infecções Estafilocócicas , Staphylococcus aureus , Centros de Atenção Terciária , Humanos , Etiópia/epidemiologia , Feminino , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/tratamento farmacológico , Adulto , Masculino , Staphylococcus aureus/genética , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/isolamento & purificação , Antibacterianos/farmacologia , Pessoa de Meia-Idade , Testes de Sensibilidade Microbiana , Adolescente , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Adulto Jovem , Fatores de Virulência/genética , Leucocidinas/genética , Criança , Exotoxinas/genética , Pré-Escolar , Infecção Hospitalar/microbiologia , Infecção Hospitalar/epidemiologia , Farmacorresistência Bacteriana/genética , Lactente , Idoso , Toxinas BacterianasRESUMO
Three family members attended their general practice and emergency department over a 3-month period with recurrent skin and soft tissue infections (SSTIs) such as paronychia, submandibular carbuncle and groin and gluteal abscess requiring surgical drainage. Only when two family members were concurrently admitted with abscesses requiring drainage under general anaesthetic was the definitive diagnosis reached. The wound swabs identified methicillin-resistant Staphylococcus aureus (MRSA) and subsequent identification of the exotoxin Panton-Valentine leukocidin (PVL). Following MRSA decolonisation therapy with mupirocin and octenidine, only one family member has had one recurrence of an SSTI with MRSA isolated from the wound. When patients present with a history of recurrent SSTIs or a family all have had similar presentations, the clinician should consider MRSA with PVL exotoxin infection. Then patients must be referred for confirmation to ensure management is effective for the SSTI and prescribe MRSA decolonisation therapy concurrently to reduce recurrence.
Assuntos
Toxinas Bacterianas , Exotoxinas , Leucocidinas , Staphylococcus aureus Resistente à Meticilina , Recidiva , Infecções dos Tecidos Moles , Humanos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Infecções dos Tecidos Moles/microbiologia , Infecções dos Tecidos Moles/terapia , Infecções dos Tecidos Moles/tratamento farmacológico , Masculino , Feminino , Infecções Cutâneas Estafilocócicas/tratamento farmacológico , Infecções Cutâneas Estafilocócicas/microbiologia , Antibacterianos/uso terapêutico , Adulto , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/diagnóstico , Infecções Estafilocócicas/microbiologia , Pessoa de Meia-Idade , Mupirocina/uso terapêuticoRESUMO
AIMS: Since December 2022, an increase in invasive disease caused by Streptococcus pyogenes has been observed in the Czech Republic, with a shift in the clinical presentation and age of patients. Unlike in previous years, invasive disease is more common in children and adolescents under 18 years of age and in previously healthy middle-aged adults. An increase has been noticed in the number of S. pyogenes isolates from primarily sterile sites such as haemoculture, cerebrospinal fluid, pleural effusion fluid, joint fluid, and postmortem specimens. Routine emm gene typing revealed emm1 to be the predominant emm type of S. pyogenes. Between January 2023 and July 2023, 46% of all S. pyogenes isolates from invasive cases were assigned to the emm1 type. The globally spread M1UK sublineage is characterized by differences in the expression of seven genes, including the streptococcal pyrogenic toxin A (speA) gene, compared to historical emm1 iGAS strains. The aim of this study is to determine whether the more toxigenic M1UK sublineage is associated with the increase in invasive disease in the Czech Republic. METHODS: Whole genome sequencing of 41 S. pyogenes isolates from patients with invasive disease recovered in the Czech Republic in 2018 and 2019 and from December 2022 to May 2023 was performed using the MiSeq instrument (Illumina). Bioinformatics analysis was performed using freely available online tools the Bacterial and Viral Bioinformatics Resource Center. RESULTS: Based on whole genome sequencing data of 41 emm1 isolates of S. pyogenes from patients with invasive infectious disease recovered in 2018 and 2019 and from December 2022 to May 2023, the M1UK sublineage was found to be predominant from December 2022 to May 2023. CONCLUSION: The reason for the spread of the M1UK sublineage in the Czech Republic late in 2022 and in the first half of 2023 is not entirely clear, but it may be related to reduced immunity due to limited GAS transmission during lockdowns, especially in children. Another factor that may have contributed to the high incidence of invasive infectious diseases is the seasonal circulation of respiratory viruses.
Assuntos
Antígenos de Bactérias , Proteínas da Membrana Bacteriana Externa , Proteínas de Transporte , Infecções Estreptocócicas , Streptococcus pyogenes , Humanos , República Tcheca/epidemiologia , Streptococcus pyogenes/genética , Streptococcus pyogenes/isolamento & purificação , Infecções Estreptocócicas/microbiologia , Infecções Estreptocócicas/epidemiologia , Adolescente , Antígenos de Bactérias/genética , Criança , Proteínas de Transporte/genética , Adulto , Proteínas da Membrana Bacteriana Externa/genética , Pré-Escolar , Pessoa de Meia-Idade , Prevalência , Adulto Jovem , Proteínas de Bactérias/genética , Lactente , Feminino , Masculino , Exotoxinas/genética , IdosoRESUMO
Continued detection of Panton-Valentine leukocidin-positive Staphylococcus aureus in samples from a family with severe repeated skin infections and their pet cat suggests transmission between the family and the cat. Decolonizing the pet led to successful elimination of the bacteria from the household. Clinicians should consider pet cats as possible reinfection sources.
Assuntos
Toxinas Bacterianas , Exotoxinas , Leucocidinas , Animais de Estimação , Infecções Estafilocócicas , Staphylococcus aureus , Leucocidinas/genética , Exotoxinas/genética , Gatos , Toxinas Bacterianas/genética , Animais , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Animais de Estimação/microbiologia , Humanos , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/veterinária , Masculino , Doenças do Gato/microbiologia , Doenças do Gato/diagnóstico , Feminino , Infecções Cutâneas Estafilocócicas/microbiologia , Infecções Cutâneas Estafilocócicas/veterinária , Família , AdultoRESUMO
The epidermal growth factor receptor (EGFR) is an important target for cancer therapies. Many head and neck cancer (HNC) cells have been reported to overexpress EGFR; therefore, anti-EGFR therapies have been attempted in patients with HNC. However, its clinical efficacy is limited owing to the development of drug resistance. In this study, we developed an EGFR-targeting immunotoxin consisting of a clinically proven anti-EGFR IgG (cetuximab; CTX) and a toxin fragment (LR-LO10) derived from Pseudomonas exotoxin A (PE) using a novel site-specific conjugation technology (peptide-directed photo-crosslinking reaction), as an alternative option. The immunotoxin (CTX-LR-LO10) showed specific binding to EGFR and properties of a typical IgG, such as stability, interactions with receptors of immune cells, and pharmacokinetics, and inhibited protein synthesis via modification of elongation factor-2. Treatment of EGFR-positive HNC cells with the immunotoxin resulted in apoptotic cell death and the inhibition of cell migration and invasion. The efficacy of CTX-LR-LO10 was evaluated in xenograft mouse models, and the immunotoxin exhibited much stronger tumor suppression than CTX or LR-LO10. Transcriptome analyses revealed that the immunotoxins elicited immune responses and altered the expression of genes related to its mechanisms of action. These results support the notion that CTX-LR-LO10 may serve as a new therapeutic agent targeting EGFR-positive cancers.
Assuntos
ADP Ribose Transferases , Receptores ErbB , Exotoxinas , Neoplasias de Cabeça e Pescoço , Imunoglobulina G , Imunotoxinas , Exotoxina A de Pseudomonas aeruginosa , Fatores de Virulência , Humanos , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/metabolismo , Receptores ErbB/imunologia , Animais , Imunotoxinas/farmacologia , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/imunologia , Neoplasias de Cabeça e Pescoço/metabolismo , Camundongos , Imunoglobulina G/farmacologia , Linhagem Celular Tumoral , Exotoxinas/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto , Cetuximab/farmacologia , Camundongos Nus , Toxinas Bacterianas , Apoptose/efeitos dos fármacos , Camundongos Endogâmicos BALB C , Feminino , Movimento Celular/efeitos dos fármacos , Antineoplásicos/farmacologiaRESUMO
INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) expresses the Panton-Valentine leukocidin (PVL) virulence gene, which is associated with community and hospital-acquired severe MRSA infections. The objective of this study was to determine the prevalence and antibiotic susceptibility profile with a focus on the presence of the PVL gene among MRSA isolates in healthcare settings. METHODOLOGY: A total of 1,207 clinical specimens and 304 hospital environment swabs were collected in a tertiary care hospital in Nepal, and investigated following basic microbiological techniques. S. aureus was confirmed with the coagulase test. An antibiotic susceptibility test (AST) was performed by the Kirby-Bauer method and screening for MRSA was carried out by the cefoxitin disc diffusion method guided by the Clinical and Laboratory Standards Institute (CLSI), 2020. DNA was extracted and used in a polymerase chain reaction (PCR) to detect mecA and PVL genes. RESULTS: Of the 1,511 samples, 45 (2.9%) S. aureus (23 clinical and 22 environmental) were isolated. Among them, 69.6% (16/23) and 27.3% (6/22) were MRSA in clinical and environmental isolates, respectively. Twelve (52.2%) clinical isolates and seven (31.8%) environmental isolates were multidrug resistant. The majority of isolates were susceptible to vancomycin and linezolid. The PVL gene was detected in 18.2% (n = 4/22) of the MRSA isolates, of which three were from clinical sources and one was from an environmental swab. CONCLUSIONS: The prevalence of MRSA, and PVL-producing S. aureus were higher in the hospital setting. Hence, immediate and urgent implementation of infection control and sanitation measures are needed in the hospital.
Assuntos
Antibacterianos , Toxinas Bacterianas , Exotoxinas , Leucocidinas , Staphylococcus aureus Resistente à Meticilina , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas , Centros de Atenção Terciária , Leucocidinas/genética , Exotoxinas/genética , Nepal/epidemiologia , Humanos , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Toxinas Bacterianas/genética , Centros de Atenção Terciária/estatística & dados numéricos , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/epidemiologia , Antibacterianos/farmacologia , Prevalência , Feminino , Adulto , Masculino , Infecção Hospitalar/microbiologia , Infecção Hospitalar/epidemiologia , Pessoa de Meia-Idade , Adulto Jovem , Adolescente , Proteínas de Bactérias/genéticaRESUMO
Athletes are vulnerable to Staphylococcus aureus infections due to skin-to-skin contact and skin abrasions during training and competitions involving sharied sport equipment or toiletries, which promote the spread of the bacteria between athletes and within sport teams. This results not only in higher prevalence of S.aureus carriage among athletes compared to the general population, but also in outbreaks of infections, particularly skin infections, within sports teams. To limit the spread of S. aureus among athletes, a decolonization protocol can be applied when clustered cases of S. aureus infections occur, especially if Panton-Valentine leukocidin-producing strains are implicated. Finally, to avoid exposing athletes to S.aureus transmission/colonization, it is recommended to establish strict and clearly formulated individual and collective hygiene rules and to regularly disinfect shared sports equipment.
Assuntos
Atletas , Esportes , Infecções Estafilocócicas , Staphylococcus aureus , Humanos , Staphylococcus aureus/isolamento & purificação , Staphylococcus aureus/efeitos dos fármacos , Infecções Estafilocócicas/epidemiologia , Portador Sadio/epidemiologia , Paris/epidemiologia , Toxinas Bacterianas , Leucocidinas , Exotoxinas , Prevalência , Higiene , Equipamentos Esportivos , Aniversários e Eventos Especiais , Surtos de Doenças/prevenção & controleRESUMO
BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen that can cause many community and hospital-acquired infections. This study was conducted to investigate the SCCmec gene types responsible for methicillin resistance in MRSA isolates isolated from hospitalised patients. MATERIAL AND METHODS: MRSA isolates isolated from samples sent from various clinics to Gaziantep University Hospital Microbiology Laboratory between March 2021-January 2022 were included in the study. Bacteria were identified using by VITEK 2 automated system. Cefoxitin (FOX) resistance was determined by the disc diffusion method according to EUCAST standards. Cefoxitin resistance was confirmed by the Penicillin Binding Protein 2' latex agglutination test. Types of mecA, mecC, coa, nuc, Panton Valentin Leukocidin (PVL), ccrC2, class A mec, SCCmec types in isolates detected as MRSA were investigated by real-time PCR. RESULTS: In this study, 116 isolates meeting the study criteria were examined. By detecting the nuc and coa genes in all isolates by PCR, the phenotypic identification of S.aureus was confirmed. While the mecA gene was detected in all MRSA isolates, no mecC gene was detected in any isolates. Detected SCCmec types were as follows; SCCmec Type 1 (2.6%), Type II (28.4%), Type III (12.9%), Type IVa (11.2%), Type IVb (3.4%), Type IVc (3.4%), Type IVg (12.1%), Type V (0.9%), Type VII (4.3%), Type VIII (18.1%), Type IX (0.9%), Type XII (1.7%). On the other hand, SCCmec Type VI, X, XI and XIII were not found in any isolate. It was determined that four of the MRSA isolates (3.4%) carried the PVL gene that two (50%) of these were found in SCCmec Type VIII. CONCLUSION: Monitoring of FOX resistance is an effective and safe method for determination of MRSA isolates. The change in the mec gene causes resistance, which should be monitored regularly with molecular methods. Our study is the first study in Turkey.
Assuntos
Proteínas de Bactérias , Cefoxitina , Staphylococcus aureus Resistente à Meticilina , Reação em Cadeia da Polimerase em Tempo Real , Infecções Estafilocócicas , Humanos , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Staphylococcus aureus Resistente à Meticilina/classificação , Cefoxitina/farmacologia , Reação em Cadeia da Polimerase em Tempo Real/métodos , Infecções Estafilocócicas/microbiologia , Proteínas de Bactérias/genética , Antibacterianos/farmacologia , Proteínas de Ligação às Penicilinas/genética , Testes de Sensibilidade Microbiana , Leucocidinas/genética , Exotoxinas/genética , Toxinas Bacterianas/genéticaRESUMO
Staphylococcus aureus is a frequent agent of bacteraemia. This bacterium has a variety of virulence traits that allow the establishment and maintenance of infection. This study explored the virulence profile of S. aureus strains causing paediatric bacteraemia (SAB) in Manhiça district, Mozambique. We analysed 336 S. aureus strains isolated from blood cultures of children younger than 5 years admitted to the Manhiça District Hospital between 2001 and 2019, previously characterized for antibiotic susceptibility and clonality. The strains virulence potential was evaluated by PCR detection of the Panton-Valentine leucocidin (PVL) encoding genes, lukS-PV/lukF-PV, assessment of the capacity for biofilm formation and pathogenicity assays in Galleria mellonella. The overall carriage of PVL-encoding genes was over 40%, although reaching ~ 70 to 100% in the last years (2014 to 2019), potentially linked to the emergence of CC152 lineage. Strong biofilm production was a frequent trait of CC152 strains. Representative CC152 and CC121 strains showed higher virulence potential in the G. mellonella model when compared to reference strains, with variations within and between CCs. Our results highlight the importance of monitoring the emergent CC152-MSSA-PVL+ and other lineages, as they display important virulence traits that may negatively impact the management of SAB paediatric patients in Manhiça district, Mozambique.
Assuntos
Bacteriemia , Biofilmes , Infecções Comunitárias Adquiridas , Infecções Estafilocócicas , Staphylococcus aureus , Humanos , Moçambique/epidemiologia , Staphylococcus aureus/genética , Staphylococcus aureus/patogenicidade , Staphylococcus aureus/isolamento & purificação , Virulência/genética , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/epidemiologia , Biofilmes/crescimento & desenvolvimento , Pré-Escolar , Bacteriemia/microbiologia , Bacteriemia/epidemiologia , Infecções Comunitárias Adquiridas/microbiologia , Lactente , Animais , Exotoxinas/genética , Toxinas Bacterianas/genética , Leucocidinas/genética , Fatores de Virulência/genética , Feminino , Masculino , Mariposas/microbiologiaRESUMO
BACKGROUND: Staphylococcus aureus (S. aureus) associated with COVID-19 has not been well documented. This cross-sectional study evaluated the association between nasal S. aureus carriage and COVID-19. METHODS AND RESULTS: Nasopharyngeal samples were collected from 391 participants presenting for COVID-19 test in Lagos, Nigeria, and S. aureus was isolated from the samples. Antimicrobial susceptibility test was done by disc diffusion method. All S. aureus isolates were screened for the presence of mecA, panton-valentine leucocidin (PVL) and toxic shock syndrome toxin (TSST) virulence genes by polymerase chain reaction. Staphylococcal protein A (spa) typing was conducted for all the isolates. Participants with COVID-19 had double the prevalence of S. aureus (42.86%) compared to those who tested negative (20.54%). A significant association was seen between S. aureus nasal carriage and COVID-19 (p = 0.004). Antimicrobial sensitivity results showed resistance to oxacillin (100%), cefoxitin (53%), and vancomycin (98.7%). However, only 41% of the isolates harbored the mecA gene, with SCCmecV being the most common SCCmec type. There was no association between the carriage of virulence genes and COVID-19. A total of 23 Spa types were detected, with t13249 and t095 being the two most common spa types. CONCLUSION: This study examined the association between nasal S. aureus carriage and SARS-COV-2 infection. Further research is required to fully explore the implications of S. aureus co-infection with COVID-19.
Assuntos
COVID-19 , SARS-CoV-2 , Infecções Estafilocócicas , Staphylococcus aureus , Humanos , COVID-19/microbiologia , COVID-19/epidemiologia , COVID-19/virologia , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , Estudos Transversais , Masculino , Feminino , Staphylococcus aureus/genética , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/patogenicidade , Staphylococcus aureus/isolamento & purificação , Adulto , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , Pessoa de Meia-Idade , Toxinas Bacterianas/genética , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Comorbidade , Proteínas de Bactérias/genética , Virulência/genética , Nigéria/epidemiologia , Farmacorresistência Bacteriana Múltipla/genética , Antibacterianos/farmacologia , Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Testes de Sensibilidade Microbiana , Proteínas de Ligação às Penicilinas/genética , Leucocidinas/genética , Exotoxinas/genética , Fatores de Virulência/genética , Adulto JovemRESUMO
Streptococcus pyogenes is a significant human pathogen, producing a range of virulence factors, including streptococcal pyrogenic exotoxin B (SpeB) that is associated with foodborne outbreaks. It was only known that this cysteine protease mediates cleavage of transmembrane proteins to permit bacterial penetration and is found in 25% of clinical isolates from streptococcal toxic shock syndrome patients with extreme inflammation. Its interaction with host and streptococcal proteins has been well characterized, but doubt remains about whether it constitutes a superantigen. In this study, for the first time it is shown that SpeB acts as a superantigen, similarly to other known superantigens such as staphylococcal enterotoxin A or streptococcal pyrogenic exotoxin type C, by inducing proliferation of murine splenocytes and cytokine secretion, primarily of interleukin-2 (IL-2), as shown by cytometric bead array analysis. IL-2 secretion was confirmed by enzyme-linked immunosorbent assay (ELISA) as well as secretion of interferon-γ. ELISA showed a dose-dependent relationship between SpeB concentration in splenocyte cells and IL-2 secretion levels, and it was shown that SpeB retains activity in milk pasteurized for 30 min at 63°C.
Assuntos
Proteínas de Bactérias , Proliferação de Células , Exotoxinas , Interferon gama , Interleucina-2 , Baço , Streptococcus pyogenes , Superantígenos , Animais , Interleucina-2/metabolismo , Superantígenos/imunologia , Superantígenos/metabolismo , Exotoxinas/metabolismo , Exotoxinas/imunologia , Interferon gama/metabolismo , Interferon gama/imunologia , Camundongos , Baço/microbiologia , Baço/citologia , Baço/imunologia , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Streptococcus pyogenes/imunologia , Streptococcus pyogenes/metabolismo , Feminino , Camundongos Endogâmicos BALB CRESUMO
Clostridium perfringens is a kind of anaerobic Gram-positive bacterium that widely exists in the intestinal tissue of humans and animals. And the main virulence factor in Clostridium perfringens is its exotoxins. Clostridium perfringens type C is the main strain of livestock disease, its exotoxins can induce necrotizing enteritis and enterotoxemia, which lead to the reduction in feed conversion, and a serious impact on breeding production performance. Our study found that treatment with exotoxins reduced cell viability and triggered intracellular reactive oxygen species (ROS) in human mononuclear leukemia cells (THP-1) cells. Through transcriptome sequencing analysis, we found that the levels of related proteins such as heme oxygenase 1 (HO-1) and ferroptosis signaling pathway increased significantly after treatment with exotoxins. To investigate whether ferroptosis occurred after exotoxin treatment in macrophages, we confirmed that the protein expression levels of antioxidant factors glutathione peroxidase 4/ferroptosis-suppressor-protein 1/the cystine/glutamate antiporter solute carrier family 7 member 11 (GPX4/FSP1/xCT), ferroptosis-related protein nuclear receptor coactivator 4/transferrin/transferrin receptor (NCOA4/TF/TFR)/ferritin and the level of lipid peroxidation were significantly changed. Based on the above results, our study suggested that Clostridium perfringens type C exotoxins can induce macrophage injury through oxidative stress and ferroptosis.
Assuntos
Antioxidantes , Clostridium perfringens , Animais , Humanos , Antiporters , Exotoxinas , Ácido GlutâmicoRESUMO
BACKGROUND: We aimed to investigate the clinical features, antimicrobial susceptibility and pvl gene expression in Staphylococcus aureus causing acute hematogenous bone and joint infections (BJIs) in children in Vietnam. METHODS: In this prospective study, the demographics, microbiology and clinical outcomes of pediatric patients with acute hematogenous BJIs were collected from September 2022 to September 2023. Antimicrobial susceptibility profiles were determined using VITEK2 Compact system. The pvl gene encoding the Panton-Valentine leukocidin (PVL) toxin was detected by using polymerase chain reaction. Mann-Whitney, χ 2 and Fisher test were used for statistical analysis. RESULTS: In total, 78 patients (46 boys) with S. aureus acute hematogenous BJIs were recruited at the National Children's Hospital, Hanoi, Vietnam. Of all S. aureus isolates, 84.6% were methicillin-resistant S. aureus . All S. aureus isolates were susceptible to vancomycin, ciprofloxacin and levofloxacin; 97% of methicillin-resistant S. aureus isolates was resistant to clindamycin (minimum inhibitory concentration ≥8 µg/mL). The pvl gene was detected in 83.3% of isolates, including 57 methicillin-resistant S. aureus isolates. Patients in the pvl -positive group had significantly higher C-reactive protein levels than those in the pvl -negative group ( P = 0.04). In addition, all 8 children with septic shock were infected with pvl -positive S. aureus . CONCLUSIONS: PVL is a prevalent virulence factor of S. aureus in Vietnam. Furthermore, high inflammatory parameters (C-reactive protein) may be present at the time of diagnosis in PVL positivity-related acute hematogenous BJIs. Further research is necessary to enhance our understanding of the varying correlations between virulence factors and outcomes of S. aureus BJIs.
Assuntos
Antibacterianos , Toxinas Bacterianas , Exotoxinas , Hospitais Pediátricos , Leucocidinas , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas , Staphylococcus aureus , Centros de Atenção Terciária , Humanos , Leucocidinas/genética , Exotoxinas/genética , Vietnã/epidemiologia , Masculino , Feminino , Toxinas Bacterianas/genética , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/epidemiologia , Pré-Escolar , Staphylococcus aureus/genética , Staphylococcus aureus/efeitos dos fármacos , Estudos Prospectivos , Criança , Centros de Atenção Terciária/estatística & dados numéricos , Prevalência , Lactente , Antibacterianos/farmacologia , Artrite Infecciosa/microbiologia , Artrite Infecciosa/epidemiologia , Adolescente , Osteomielite/microbiologia , Osteomielite/epidemiologiaRESUMO
Antibiotic resistance has become an urgent threat to health care in recent years. The use of drug delivery systems provides advantages over conventional administration of antibiotics and can slow the development of antibiotic resistance. In the current study, we developed a toxin-triggered liposomal antibiotic delivery system, in which the drug release is enabled by the leukotoxin (LtxA) produced by the Gram-negative pathogen, Aggregatibacter actinomycetemcomitans. LtxA has previously been shown to mediate membrane disruption by promoting a lipid phase change in nonlamellar lipids, such as 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-methyl (N-methyl-DOPE). In addition, LtxA has been observed to bind strongly and nearly irreversibly to membranes containing large amounts of cholesterol. Here, we designed a liposomal delivery system composed of N-methyl-DOPE and cholesterol to take advantage of these interactions. Specifically, we hypothesized that liposomes composed of N-methyl-DOPE and cholesterol, encapsulating antibiotics, would be sensitive to LtxA, enabling controlled antibiotic release. We observed that liposomes composed of N-methyl-DOPE were sensitive to the presence of low concentrations of LtxA, and cholesterol increased the extent and kinetics of content release. The liposomes were stable under various storage conditions for at least 7 days. Finally, we showed that antibiotic release occurs selectively in the presence of an LtxA-producing strain of A. actinomycetemcomitans but not in the presence of a non-LtxA-expressing strain. Together, these results demonstrate that the designed liposomal vehicle enables toxin-triggered delivery of antibiotics to LtxA-producing strains of A. actinomycetemcomitans.
Assuntos
Aggregatibacter actinomycetemcomitans , Antibacterianos , Lipossomos , Lipossomos/química , Antibacterianos/farmacologia , Antibacterianos/química , Aggregatibacter actinomycetemcomitans/efeitos dos fármacos , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacologia , Liberação Controlada de Fármacos , Colesterol/química , Colesterol/metabolismo , Testes de Sensibilidade Microbiana , Exotoxinas/metabolismo , Exotoxinas/química , Fosfatidiletanolaminas/química , Sistemas de Liberação de MedicamentosRESUMO
AIM: Due to the importance of exotoxin A and pyocyanin in the pathogenicity of this bacterium, we decided to evaluate the prevalence of genes encoding these virulence factors in clinical isolates of P.aeruginosa.
Assuntos
Infecções por Pseudomonas , Piocianina , Humanos , Pseudomonas aeruginosa/genética , Proteínas de Bactérias/genética , Exotoxinas/genética , Fatores de Virulência/genética , Infecções por Pseudomonas/epidemiologia , Infecções por Pseudomonas/microbiologiaRESUMO
This study aimed to determine resistance to antimicrobials of Staphylococcus aureus strains isolated from clinical specimens in Lithuanian hospitals and to identify the genes conferring resistance and virulence. The study was carried out from June 2019 to September 2021. S. aureus strains were isolated from skin, soft tissues, blood, lower respiratory tract, urine and other specimens. Antibiotic susceptibility testing was performed using the disc diffusion method according to EUCAST guidelines. All isolates were analyzed for detection of the ermA, ermC, mecA, mecC, tetK, tetM, and lukF-PV genes by multiplex real-time PCR. The 16S rRNA coding sequence was applied as an internal PCR control. Altogether, 745 S. aureus strains were analyzed. Antimicrobial susceptibility testing revealed that all isolates were susceptible to rifampin and vancomycin. Of the 745 strains, 94.8% were susceptible to tetracycline, 94.5% to clindamycin, and 88.3% to erythromycin. The lowest susceptibility rate was found for penicillin (25.8%). Six percent of the tested strains were methicillin-resistant S. aureus (MRSA). The majority of methicillin-resistant strains were isolated from skin and soft tissues (73.3%), with a smaller portion isolated from blood (17.8%) and respiratory tract (8.9%). The ermC gene was detected in 41.1% of erythromycin-resistant S. aureus strains, whereas ermA was detected in 32.2% of erythromycin-resistant S. aureus strains. 69.2% of tetracycline-resistant S. aureus strains had tetK gene, and 28.2% had tetM gene. 7.3% of S. aureus isolates harbored lukF-PV gene. The frequency of the pvl gene detection was significantly higher in MRSA isolates than in methicillin-susceptible S. aureus isolates (p < 0.0001).
Assuntos
Toxinas Bacterianas , Exotoxinas , Leucocidinas , Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Humanos , Staphylococcus aureus/genética , Antibacterianos/farmacologia , Lituânia/epidemiologia , Prevalência , Staphylococcus aureus Resistente à Meticilina/genética , RNA Ribossômico 16S , Farmacorresistência Bacteriana , Infecções Estafilocócicas/epidemiologia , Eritromicina , TetraciclinaRESUMO
Large transcellular pores elicited by bacterial mono-ADP-ribosyltransferase (mART) exotoxins inhibiting the small RhoA GTPase compromise the endothelial barrier. Recent advances in biophysical modeling point toward membrane tension and bending rigidity as the minimal set of mechanical parameters determining the nucleation and maximal size of transendothelial cell macroaperture (TEM) tunnels induced by bacterial RhoA-targeting mART exotoxins. We report that cellular depletion of caveolin-1, the membrane-embedded building block of caveolae, and depletion of cavin-1, the master regulator of caveolae invaginations, increase the number of TEMs per cell. The enhanced occurrence of TEM nucleation events correlates with a reduction in cell height due to the increase in cell spreading and decrease in cell volume, which, together with the disruption of RhoA-driven F-actin meshwork, favor membrane apposition for TEM nucleation. Strikingly, caveolin-1 specifically controls the opening speed of TEMs, leading to their dramatic 5.4-fold larger widening. Consistent with the increase in TEM density and width in siCAV1 cells, we record a higher lethality in CAV1 KO mice subjected to a catalytically active mART exotoxin targeting RhoA during staphylococcal bloodstream infection. Combined theoretical modeling with independent biophysical measurements of plasma membrane bending rigidity points toward a specific contribution of caveolin-1 to membrane stiffening in addition to the role of cavin-1/caveolin-1-dependent caveolae in the control of membrane tension homeostasis.
Assuntos
Caveolina 1 , Células Endoteliais , Animais , Camundongos , Cavéolas/metabolismo , Caveolina 1/metabolismo , Membrana Celular/metabolismo , Células Endoteliais/metabolismo , Exotoxinas/metabolismoRESUMO
RTX toxins are important virulence factors produced by a wide range of Gram-negative bacteria. They are secreted as water-soluble proteins that are able to bind to the host cell membrane and insert hydrophobic segments into the lipid bilayer that ultimately contribute to the formation of transmembrane pores. Ion diffusion through these pores leads then to cytotoxic and cytolytic effects on the hosts. Several reports have evidenced that the binding of several RTX toxins to the target cell membrane may take place through a high-affinity interaction with integrins of the ß2 family that is highly expressed in immune cells of the myeloid lineage. However, at higher toxin doses, cytotoxicity by most RTX toxins has been observed also on ß2-deficient cells in which toxin binding to the cell membrane has been proposed to occur through interaction with glycans of glycosylated lipids or proteins present in the membrane. More recently, cumulative pieces of evidence show that membrane cholesterol is essential for the mechanism of action of several RTX toxins. Here, we summarize the most important aspects of the RTX toxin interaction with the target cell membrane, including the cholesterol dependence, the recent identification in the sequences of several RTX toxins of linear motifs coined as the Cholesterol Recognition/interaction Amino acid Consensus (CRAC), and the reverse or mirror CARC motif, which is involved in the toxin-cholesterol interaction.
Assuntos
Toxinas Bacterianas , Toxinas Bacterianas/metabolismo , Membrana Celular/metabolismo , Bicamadas Lipídicas/metabolismo , Exotoxinas/metabolismo , Colesterol/metabolismoRESUMO
Delayed wound healing caused by bacterial infection remains a major challenge in clinical treatment. Exotoxins incorporated in bacterial extracellular vesicles play a key role as the disease-causing virulence factors. Safe and specific antivirulence agents are expected to be developed as an effective anti-bacterial infection strategy, instead of single antibiotic therapy. Plant-derived extracellular vesicle-like nanoparticles have emerged as promising therapeutic agents for skin diseases, but the elucidations of specific mechanisms of action and clinical transformation still need to be advanced. Here, dandelion-derived extracellular vesicle-like nanoparticles (TH-EVNs) are isolated and exert antivirulence activity through specifically binding to Staphylococcus aureus (S. aureus) exotoxins, thereby protecting the host cell from attack. The neutralization of TH-EVNs against exotoxins has considerable binding force and stability, showing complete detoxification effect in vivo. Then gelatin methacryloyl hydrogel is developed as TH-EVNs-loaded dressing for S. aureus exotoxin-invasive wounds. Hydrogel dressings demonstrate good physical and mechanical properties, thus achieving wound retention and controlled release of TH-EVNs, in addition to promoting cell proliferation and migration. In vivo results show accelerated re-epithelialization, promotion of collagen maturity and reduction of inflammation after treatment. Collectively, the developed TH-EVNs-laden hydrogel dressings provide a potential therapeutic approach for S. aureus exotoxin- associated trauma.
Assuntos
Anti-Infecciosos , Infecções Estafilocócicas , Taraxacum , Hidrogéis/química , Staphylococcus aureus , Cicatrização , Exotoxinas , Antibacterianos/farmacologia , Infecções Estafilocócicas/tratamento farmacológico , BandagensRESUMO
OBJECTIVES: Globally, the isolation of community-associated methicillin-resistant Staphylococcus aureus (MRSA) harbouring both the Panton-Valentine leucocidin (PVL) and toxic shock syndrome toxin 1 (TSST-1) genes is rare. However, we encountered an outbreak of the ST22-PT clone exhibiting this phenotype in Japan. Notably, the TSST-1 gene was duplicated in most of the strains. This study aimed to elucidate the mechanisms underlying this gene duplication. METHODS: A total of 90 MRSA isolates were collected from the skin of outpatients in Fukuoka City, Japan, between 2017 and 2019. Whole-genome sequencing was performed on MRSA strains that were PVL and TSST-1 positive. RESULTS: A total of 43 (47.8%) strains produced TSST-1, 20 (22.2%) produced PVL, and 16 (17.8%) produced both. Fifteen isolates were classified as ST22/SCCmec type IVa (ST22-PT clone) and one as ST1/SCCmec type V (ST1-PT clone). Three distinct ST22-PT clones were identified: Fukuoka clone I (one PVL gene and one TSST-1 gene), Fukuoka clone II (addition of a TSST-1 gene to Fukuoka clone I), and Fukuoka clone III (marked by a chromosomal inversion in a large region from Fukuoka clone II). DISCUSSION: Fukuoka clone I may have integrated a novel pathogenicity island bearing the TSST-1 gene, leading to the emergence of Fukuoka clone II with a duplicated TSST-1 gene. This duplication subsequently instigated a chromosomal inversion in a large region owing to the homologous sequence surrounding TSST-1, giving rise to Fukuoka clone III. These findings provide crucial insights into the genetic evolution of MRSA.