RESUMEN
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.
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Antibacterianos , Personal de Salud , Infecciones Estafilocócicas , Staphylococcus aureus , Centros de Atención Terciaria , Humanos , Etiopía/epidemiología , Femenino , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/tratamiento farmacológico , Adulto , Masculino , Staphylococcus aureus/genética , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/aislamiento & purificación , Antibacterianos/farmacología , Persona de Mediana Edad , Pruebas de Sensibilidad Microbiana , Adolescente , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Adulto Joven , Factores de Virulencia/genética , Leucocidinas/genética , Niño , Exotoxinas/genética , Preescolar , Infección Hospitalaria/microbiología , Infección Hospitalaria/epidemiología , Farmacorresistencia Bacteriana/genética , Lactante , Anciano , Toxinas BacterianasRESUMEN
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.
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Toxinas Bacterianas , Exotoxinas , Leucocidinas , Staphylococcus aureus Resistente a Meticilina , Recurrencia , Infecciones de los Tejidos Blandos , Humanos , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Infecciones de los Tejidos Blandos/microbiología , Infecciones de los Tejidos Blandos/terapia , Infecciones de los Tejidos Blandos/tratamiento farmacológico , Masculino , Femenino , Infecciones Cutáneas Estafilocócicas/tratamiento farmacológico , Infecciones Cutáneas Estafilocócicas/microbiología , Antibacterianos/uso terapéutico , Adulto , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/diagnóstico , Infecciones Estafilocócicas/microbiología , Persona de Mediana Edad , Mupirocina/uso terapéuticoRESUMEN
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.
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Antibacterianos , Toxinas Bacterianas , Exotoxinas , Leucocidinas , Staphylococcus aureus Resistente a Meticilina , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas , Centros de Atención Terciaria , Leucocidinas/genética , Exotoxinas/genética , Nepal/epidemiología , Humanos , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Toxinas Bacterianas/genética , Centros de Atención Terciaria/estadística & datos numéricos , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/epidemiología , Antibacterianos/farmacología , Prevalencia , Femenino , Adulto , Masculino , Infección Hospitalaria/microbiología , Infección Hospitalaria/epidemiología , Persona de Mediana Edad , Adulto Joven , Adolescente , Proteínas Bacterianas/genéticaRESUMEN
Staphylococcus aureus (S. aureus) is an opportunistic infectious pathogen, which causes a high mortality rate during bloodstream infections. The early detection of virulent strains in patients' blood samples is of medical interest for rapid diagnosis. The main virulent factors identified in patient isolates include leukocidins that bind to specific membrane receptors and lyse immune cells and erythrocytes. Duffy antigen receptor for chemokines (DARC) on the surface of specific cells is a main target of leukocidins such as gamma-hemolysin AB (HlgAB) and leukocidin ED (LukED). Among them, HlgAB is a conserved and critical leukocidin that binds to DARC and forms pores on the cell membranes, leading to cell lysis. Current methods are based on ELISA or bacterial culture, which takes hours to days. For detecting HlgAB with faster response and higher sensitivity, we developed a biosensor that combines single-walled carbon nanotube field effect transistors (swCNT-FETs) with immobilized DARC receptors as biosensing elements. DARC was purified from a bacterial expression system and successfully reconstituted into nanodiscs that preserve binding capability for HlgAB. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) showed an increase of the DARC-containing nanodisc size in the presence of HlgAB, indicating the formation of HlgAB prepore or pore complexes. We demonstrate that this sensor can specifically detect the leukocidins HlgA and HlgAB in a quantitative manner within the dynamic range of 1 fM to 100 pM with an LOD of 0.122 fM and an LOQ of 0.441 fM. The sensor was challenged with human serum spiked with HlgAB as simulated clinical samples. After dilution for decreasing nonspecific binding, it selectively detected the toxin with a similar detection range and apparent dissociation constant as in the buffer. This biosensor was demonstrated with remarkable sensitivity to detect HlgAB rapidly and has the potential as a tool for fundamental research and clinical applications, although this sensor cannot differentiate between HlgAB and LukED as both have the same receptor.
Asunto(s)
Técnicas Biosensibles , Sistema del Grupo Sanguíneo Duffy , Leucocidinas , Staphylococcus aureus , Técnicas Biosensibles/métodos , Sistema del Grupo Sanguíneo Duffy/química , Sistema del Grupo Sanguíneo Duffy/metabolismo , Leucocidinas/química , Leucocidinas/metabolismo , Humanos , Staphylococcus aureus/aislamiento & purificación , Staphylococcus aureus/metabolismo , Proteínas Hemolisinas/química , Proteínas Hemolisinas/metabolismo , Receptores de Superficie Celular/metabolismo , Receptores de Superficie Celular/química , Nanotubos de Carbono/química , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Toxinas Bacterianas/química , Toxinas Bacterianas/metabolismoRESUMEN
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.
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Toxinas Bacterianas , Exotoxinas , Leucocidinas , Mascotas , Infecciones Estafilocócicas , Staphylococcus aureus , Leucocidinas/genética , Exotoxinas/genética , Gatos , Toxinas Bacterianas/genética , Animales , Staphylococcus aureus/genética , Staphylococcus aureus/aislamiento & purificación , Mascotas/microbiología , Humanos , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/veterinaria , Masculino , Enfermedades de los Gatos/microbiología , Enfermedades de los Gatos/diagnóstico , Femenino , Infecciones Cutáneas Estafilocócicas/microbiología , Infecciones Cutáneas Estafilocócicas/veterinaria , Familia , AdultoRESUMEN
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.
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Proteínas Bacterianas , Cefoxitina , Staphylococcus aureus Resistente a Meticilina , Reacción en Cadena en Tiempo Real de la Polimerasa , Infecciones Estafilocócicas , Humanos , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Staphylococcus aureus Resistente a Meticilina/clasificación , Cefoxitina/farmacología , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Infecciones Estafilocócicas/microbiología , Proteínas Bacterianas/genética , Antibacterianos/farmacología , Proteínas de Unión a las Penicilinas/genética , Pruebas de Sensibilidad Microbiana , Leucocidinas/genética , Exotoxinas/genética , Toxinas Bacterianas/genéticaRESUMEN
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.
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Atletas , Deportes , Infecciones Estafilocócicas , Staphylococcus aureus , Humanos , Staphylococcus aureus/aislamiento & purificación , Staphylococcus aureus/efectos de los fármacos , Infecciones Estafilocócicas/epidemiología , Portador Sano/epidemiología , Paris/epidemiología , Toxinas Bacterianas , Leucocidinas , Exotoxinas , Prevalencia , Higiene , Equipo Deportivo , Aniversarios y Eventos Especiales , Brotes de Enfermedades/prevención & controlRESUMEN
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.
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Bacteriemia , Biopelículas , Infecciones Comunitarias Adquiridas , Infecciones Estafilocócicas , Staphylococcus aureus , Humanos , Mozambique/epidemiología , Staphylococcus aureus/genética , Staphylococcus aureus/patogenicidad , Staphylococcus aureus/aislamiento & purificación , Virulencia/genética , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/epidemiología , Biopelículas/crecimiento & desarrollo , Preescolar , Bacteriemia/microbiología , Bacteriemia/epidemiología , Infecciones Comunitarias Adquiridas/microbiología , Lactante , Animales , Exotoxinas/genética , Toxinas Bacterianas/genética , Leucocidinas/genética , Factores de Virulencia/genética , Femenino , Masculino , Mariposas Nocturnas/microbiologíaRESUMEN
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.
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COVID-19 , SARS-CoV-2 , Infecciones Estafilocócicas , Staphylococcus aureus , Humanos , COVID-19/microbiología , COVID-19/epidemiología , COVID-19/virología , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/microbiología , Estudios Transversales , Masculino , Femenino , Staphylococcus aureus/genética , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/patogenicidad , Staphylococcus aureus/aislamiento & purificación , Adulto , SARS-CoV-2/genética , SARS-CoV-2/aislamiento & purificación , Persona de Mediana Edad , Toxinas Bacterianas/genética , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Staphylococcus aureus Resistente a Meticilina/patogenicidad , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Comorbilidad , Proteínas Bacterianas/genética , Virulencia/genética , Nigeria/epidemiología , Farmacorresistencia Bacteriana Múltiple/genética , Antibacterianos/farmacología , Portador Sano/epidemiología , Portador Sano/microbiología , Pruebas de Sensibilidad Microbiana , Proteínas de Unión a las Penicilinas/genética , Leucocidinas/genética , Exotoxinas/genética , Factores de Virulencia/genética , Adulto JovenRESUMEN
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.
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Antibacterianos , Toxinas Bacterianas , Exotoxinas , Hospitales Pediátricos , Leucocidinas , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas , Staphylococcus aureus , Centros de Atención Terciaria , Humanos , Leucocidinas/genética , Exotoxinas/genética , Vietnam/epidemiología , Masculino , Femenino , Toxinas Bacterianas/genética , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/epidemiología , Preescolar , Staphylococcus aureus/genética , Staphylococcus aureus/efectos de los fármacos , Estudios Prospectivos , Niño , Centros de Atención Terciaria/estadística & datos numéricos , Prevalencia , Lactante , Antibacterianos/farmacología , Artritis Infecciosa/microbiología , Artritis Infecciosa/epidemiología , Adolescente , Osteomielitis/microbiología , Osteomielitis/epidemiologíaRESUMEN
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).
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Toxinas Bacterianas , Exotoxinas , Leucocidinas , Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Humanos , Staphylococcus aureus/genética , Antibacterianos/farmacología , Lituania/epidemiología , Prevalencia , Staphylococcus aureus Resistente a Meticilina/genética , ARN Ribosómico 16S , Farmacorresistencia Bacteriana , Infecciones Estafilocócicas/epidemiología , Eritromicina , TetraciclinaRESUMEN
Introduction: Staphylococcus aureus (S. aureus) is a prominent pathogen responsible for both hospital-acquired and community-acquired infections. Among its arsenal of virulence factors, Panton-Valentine Leucocidin (PVL) is closely associated with severe diseases such as profound skin infections and necrotizing pneumonia. Patients infected with pvl-positive S. aureus often exhibit more severe symptoms and carry a substantially higher mortality risk. Therefore, it is crucial to promptly and accurately detect pvl-positive S. aureus before initiating protective measures and providing effective antibacterial treatment. Methods: In this study, we propose a precise identification and highly sensitive detection method for pvl-positive S. aureus based on recombinase-assisted amplification and the CRISPR-ERASE strip which we previously developed. Results: The results revealed that this method achieved a detection limit of 1 copy/µL for pvl-positive plasmids within 1 hour. The method successfully identified all 25 pvl-positive and 51 pvl-negative strains among the tested 76 isolated S. aureus samples, demonstrating its concordance with qPCR. Discussion: These results show that the CRISPR-ERASE detection method for pvl-positive S. aureus has the advantages of high sensitivity and specificity, this method combines the characteristics of recombinase-assisted amplification at room temperature and the advantages of ERASE test strip visualization, which can greatly reduce the dependence on professional laboratories. It is more suitable for on-site detection than PCR and qPCR, thereby providing important value for rapid on-site detection of pvl.
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Infecciones Estafilocócicas , Staphylococcus aureus , Humanos , Staphylococcus aureus/genética , Virulencia/genética , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas/genética , Infecciones Estafilocócicas/microbiología , Leucocidinas/genética , Recombinasas/genéticaRESUMEN
Previous studies have mainly focused on outpatient cases of skin and soft tissue infections (SSTIs), with limited attention to inpatient occurrences. Thus, we aimed to compare the clinical parameters of inpatients with SSTIs, performed genomic characterization, and determined the subtypes of Panton-Valentine leucocidin (PVL) bacteriophages of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from these patients. We found that PVL-positive patients had shorter hospital stays (mean, 9 vs. 24 days; p < 0.001) and abscess resolution durations (mean, 8 vs. 13 days; p < 0.01). PVL-positive MRSA-induced SSTIs were more frequently associated with abscesses [36/55 (65.5%) vs. 15/124 (12.1%), p < 0.001], with 52.7% undergoing incision and drainage; over 80% of PVL-negative patients received incision, drainage, and antibiotics. In PVL-positive patients receiving empirical antibiotics, anti-staphylococcal agents such as vancomycin and linezolid were administered less frequently (32.7%, 18/55) than in PVL-negative patients (74.2%, 92/124), indicating that patients with PVL-positive SSTIs are more likely to require surgical drainage rather than antimicrobial treatment. We also found that the ST59 lineage was predominant, regardless of PVL status (41.3%, 74/179). Additionally, we investigated the linear structure of the lukSF-PV gene, revealing that major clusters were associated with specific STs, suggesting independent acquisition of PVL by different strain types and indicating that significant diversity was observed even within PVL-positive strains detected in the same facility. Overall, our study provides comprehensive insights into the clinical, genetic, and phage-related aspects of MRSA-induced SSTIs in hospitalized patients and contributes to a more profound understanding of the epidemiology and evolution of these pathogens in the Chinese population.
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Infecciones Comunitarias Adquiridas , Staphylococcus aureus Resistente a Meticilina , Infecciones de los Tejidos Blandos , Infecciones Estafilocócicas , Infecciones Cutáneas Estafilocócicas , Humanos , Pacientes Internos , Infecciones de los Tejidos Blandos/epidemiología , Estudios Retrospectivos , Leucocidinas/genética , Infecciones Estafilocócicas/epidemiología , Infecciones Cutáneas Estafilocócicas/epidemiología , Exotoxinas/genética , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Absceso , Infecciones Comunitarias Adquiridas/epidemiologíaRESUMEN
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.
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Toxinas Bacterianas , Enterotoxinas , Exotoxinas , Leucocidinas , Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Superantígenos , Superantígenos/genética , Toxinas Bacterianas/genética , Exotoxinas/genética , Enterotoxinas/genética , Leucocidinas/genética , Humanos , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Infecciones Estafilocócicas/microbiología , Japón/epidemiología , Secuenciación Completa del Genoma , Duplicación de Gen , Masculino , Femenino , Persona de Mediana Edad , Anciano , Brotes de Enfermedades , Evolución Molecular , Adulto , Infecciones Comunitarias Adquiridas/microbiologíaRESUMEN
Staphylococcus aureus is a gram-positive pathogen that poses a major health concern, in part due to its large array of virulence factors that allow infection and evasion of the immune system. One of these virulence factors is the bicomponent pore-forming leukocidin LukAB. The regulation of lukAB expression is not completely understood, especially in the presence of immune cells such as human polymorphonuclear neutrophils (hPMNs). Here, we screened for transcriptional regulators of lukAB during the infection of primary hPMNs. We uncovered that PerR, a peroxide sensor, is vital for hPMN-mediated induction of lukAB and that PerR upregulates cytotoxicity during the infection of hPMNs. Exposure of S. aureus to hydrogen peroxide (H2O2) alone also results in increased lukAB promoter activity, a phenotype dependent on PerR. Collectively, our data suggest that S. aureus uses PerR to sense the H2O2 produced by hPMNs to stimulate the expression of lukAB, allowing the bacteria to withstand these critical innate immune cells.IMPORTANCEStaphylococcus aureus utilizes a diverse set of virulence factors, such as leukocidins, to subvert human neutrophils, but how these toxins are regulated is incompletely defined. Here, we identified the peroxide-sensitive repressor, PerR, as a required protein involved in the induction of lukAB in the presence of primary human neutrophils, a phenotype directly linked to the ability of PerR to sense H2O2. Thus, we show that S. aureus coordinates sensing and resistance to oxidative stress with toxin production to promote pathogen survival.
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Infecciones Estafilocócicas , Staphylococcus aureus , Humanos , Neutrófilos , Peróxido de Hidrógeno/toxicidad , Peróxido de Hidrógeno/metabolismo , Factores de Virulencia/genética , Factores de Virulencia/metabolismo , Proteínas Bacterianas/metabolismo , Leucocidinas , Infecciones Estafilocócicas/microbiologíaRESUMEN
Staphylococcus aureus strains that produce the toxin Panton-Valentine leukocidin (PVL-SA) frequently cause recurrent skin and soft tissue infections. PVL binds to and kills human neutrophils, resulting in the formation of neutrophil extracellular traps (NETs), but the pathomechanism has not been extensively studied. Furthermore, it is unclear why some individuals colonized with PVL-SA experience recurring infections whereas others are asymptomatic. We thus aimed to (1) investigate how PVL exerts its pathogenicity on neutrophils and (2) identify factors that could help to explain the predisposition of patients with recurring infections. We provide genetic and pharmacological evidence that PVL-induced NET formation is independent of NADPH oxidase and reactive oxygen species production. Moreover, through NET proteome analysis we identified that the protein content of PVL-induced NETs is different from NETs induced by mitogen or the microbial toxin nigericin. The abundance of the proteins cathelicidin (CAMP), elastase (NE), and proteinase 3 (PRTN3) was lower on PVL-induced NETs, and as such they were unable to kill S. aureus. Furthermore, we found that neutrophils from affected patients express higher levels of CD45, one of the PVL receptors, and are more susceptible to be killed at a low PVL concentration than control neutrophils. Neutrophils from patients that experience recurring PVL-positive infections may thus be more sensitive to PVL-induced NET formation, which might impair their ability to combat the infection.
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Antiinfecciosos , Toxinas Bacterianas , Trampas Extracelulares , Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Humanos , Staphylococcus aureus/metabolismo , Trampas Extracelulares/metabolismo , Exotoxinas , Leucocidinas , Recurrencia , Antiinfecciosos/metabolismoRESUMEN
Panton-Valentine leukocidin (PVL) is a pore-forming exotoxin produced by certain Staphylococcus (S.) aureus strains, which is responsible for the increased virulence of the pathogen. Thus, infections caused by PVL-positive S. aureus tend to recur. Usually, the infection is a smear infection, which can cause folliculitis and purulent lid margin inflammation in addition to the classic mucocutaneous abscesses. Recently, recurrent genitoanal infections caused by PVL-positive S. aureus have also been described. In most cases, this is a sexually transmitted disease. Currently, it is assumed that most infections are imported from abroad. In addition to treatment of these infections, decolonization should be performed for prophylaxis of recurrence.
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Toxinas Bacterianas , Enfermedades de Transmisión Sexual , Infecciones Estafilocócicas , Humanos , Staphylococcus aureus , Exotoxinas , Infecciones Estafilocócicas/diagnóstico , Leucocidinas , ReinfecciónAsunto(s)
Infecciones Comunitarias Adquiridas , Infección Hospitalaria , Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Humanos , Staphylococcus aureus Resistente a Meticilina/genética , Meticilina , Infección Hospitalaria/epidemiología , Staphylococcus aureus , Hospitales , Infecciones Estafilocócicas/epidemiología , Infecciones Comunitarias Adquiridas/epidemiología , Leucocidinas , ExotoxinasRESUMEN
This paper aims to describe the investigation and control of an outbreak of USA300 ST8 Panton-Valentine leucocidin (PVL)-positive meticillin-resistant Staphylococcus aureus (MRSA), confirmed by whole genome sequencing (WGS), within a maternity and neonatal setting in the UK. The identification of two linked PVL-MRSA cases led to an outbreak investigation. A lookback exercise conducted using the infection control surveillance database, typing of saved MRSA isolates, enhanced patient screening, and staff screening were used to identify further cases. Environmental screening was also performed. Genetic relatedness between isolates was assessed by WGS. During the outbreak, 18 cases were identified between 11th July 2021 and 22nd December 2022: 10 cases were infections and eight cases were colonizations. A healthcare worker (HCW) tested positive for colonization with the same strain, and environmental swabbing identified contaminated information technology equipment in the hospital. The outbreak was brought to an end by exclusion of the colonized HCW from work, and infection prevention and control measures. Since the end of the outbreak, cases of PVL-MRSA with similar molecular profiles have been found in the community. It is likely that the HCW played a role in the transmission of PVL-MRSA. Their exclusion from work and decolonization were key to preventing further cases. WGS was valuable in identifying and linking cases. The identification of community cases of PVL-MRSA with similar molecular profiles confirms transmission of the organism outside of healthcare settings.
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Toxinas Bacterianas , Infección Hospitalaria , Brotes de Enfermedades , Exotoxinas , Control de Infecciones , Leucocidinas , Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Femenino , Humanos , Recién Nacido , Toxinas Bacterianas/genética , Infección Hospitalaria/epidemiología , Infección Hospitalaria/microbiología , Infección Hospitalaria/prevención & control , Transmisión de Enfermedad Infecciosa/prevención & control , Exotoxinas/genética , Maternidades , Control de Infecciones/métodos , Leucocidinas/genética , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Tipificación Molecular , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/prevención & control , Reino Unido/epidemiología , Secuenciación Completa del GenomaRESUMEN
In 2010 a single isolate of a trimethoprim-resistant multilocus sequence type 5, Panton-Valentine leucocidin-positive, community-associated methicillin-resistant Staphylococcus aureus (PVL-positive ST5 CA-MRSA), colloquially named WA121, was identified in northern Western Australia (WA). WA121 now accounts for ~14â% of all WA MRSA infections. To gain an understanding of the genetic composition and phylogenomic structure of WA121 isolates we sequenced the genomes of 155 WA121 isolates collected 2010-2021 and present a detailed genomic description. WA121 was revealed to be a single clonally expanding lineage clearly distinct from sequenced ST5 strains reported outside Australia. WA121 strains were typified by the presence of the distinct PVL phage φSa2wa-st5, the recently described methicillin resistance element SCCmecIVo carrying the trimethoprim resistance (dfrG) transposon Tn4791, the novel ß-lactamase transposon Tn7702 and the epidermal cell differentiation inhibitor (EDIN-A) plasmid p2010-15611-2. We present evidence that SCCmecIVo together with Tn4791 has horizontally transferred to Staphylococcus argenteus and evidence of intragenomic movement of both Tn4791 and Tn7702. We experimentally demonstrate that p2010-15611-2 is capable of horizontal transfer by conjugative mobilization from one of several WA121 isolates also harbouring a pWBG749-like conjugative plasmid. In summary, WA121 is a distinct and clonally expanding Australian PVL-positive CA-MRSA lineage that is increasingly responsible for infections in indigenous communities in northern and western Australia. WA121 harbours a unique complement of mobile genetic elements and is capable of transferring antimicrobial resistance and virulence determinants to other staphylococci.