RESUMEN

Antimicrobial resistance (AMR) is global health concern escalating rapidly in both clinical settings and environment. The effluent from pharmaceuticals and hospitals may contain diverse antibiotics, exerting selective pressure to develop AMR. To study the aquatic prevalence of drug-resistant staphylococci, sampling was done from river Yamuna (3 sites) and wastewater (7 sites) near pharmaceutical industries in Delhi-NCR, India. 59.25% (224/378) were considered presumptive staphylococci while, methicillin resistance was noted in 25% (56/224) isolates. Further, 23 methicillin-resistant coagulase negative staphylococci (MR-CoNS) of 8 different species were identified via 16S rRNA gene sequencing. Multidrug resistance (MDR) was noted in 60.87% (14/23) isolates. PCR based detection of antibiotic resistance genes revealed the number of isolates containing mecA (7/23), blaZ (6/23), msrA (10/23), aac(6')aph (2") (2/23), aph(3')-IIIa (2/23), ant(4')-Ia (1/23), dfrG (4/23), dfrA(drfS1) (3/23), tetK (1/23) and tetM (1/23). The current research highlights the concerning prevalence of MDR-CoNS in aquatic environment in Delhi.

Asunto(s)

Antibacterianos , Coagulasa , Farmacorresistencia Bacteriana Múltiple , ARN Ribosómico 16S , Staphylococcus , Aguas Residuales , India/epidemiología , Aguas Residuales/microbiología , Staphylococcus/genética , Staphylococcus/efectos de los fármacos , Staphylococcus/aislamiento & purificación , Staphylococcus/clasificación , Farmacorresistencia Bacteriana Múltiple/genética , Coagulasa/metabolismo , Coagulasa/genética , ARN Ribosómico 16S/genética , Antibacterianos/farmacología , Prevalencia , Pruebas de Sensibilidad Microbiana

RESUMEN

Infections caused by Staphylococcus aureus pose a significant global public problem. Therefore, new antibiotics and therapeutic strategies are needed to combat this pathogen. This investigation delves into the effects of iclaprim, a newly discovered inhibitor of folic acid synthesis, on S. aureus virulence. The phenotypic and genotypic effects of iclaprim were thoroughly examined in relation to virulence factors, biofilm formation, and dispersal, as well as partial virulence-encoding genes associated with exoproteins, adherence, and regulation in S. aureus MW2, N315, and ATCC 25923. Then, the in vivo effectiveness of iclaprim on S. aureus pathogenicity was explored by a Galleria mellonella larvae infection model. The use of iclaprim at sub-inhibitory concentrations (sub-MICs) resulted in a reduction of α-hemolysin (Hla) production and a differential effect on the activity of coagulase in S. aureus strains. The results of biofilm formation and eradication assay showed that iclaprim was highly effective in depolymerizing the mature biofilm of S. aureus strains at concentrations of 1 MIC or greater, however, inhibited the biofilm-forming ability of only strains N315 and ATCC 25923 at sub-MICs. Interestingly, treatment of strains with sub-MICs of iclaprim resulted in significant stimulation or suppression of most virulence-encoding genes expression. Iclaprim did not affect the production of δ-hemolysin or staphylococcal protein A (SpA), nor did it impact the total activity of proteases, nucleases, and lipases. In vivo testing showed that sub-MICs of iclaprim significantly improves infected larvae survival. The present study offered valuable insights towards a better understating of the influence of iclaprim on different strains of S. aureus. The findings suggest that iclaprim may have potential as an anti-virulence and antibiofilm agent, thus potentially mitigating the pathogenicity of S. aureus and improving clinical outcomes associated with infections caused by this pathogen. KEY POINTS: • Iclaprim effectively inhibits α-hemolysin production and biofilm formation in a strain-dependent manner and was an excellent depolymerizing agent of mature biofilm • Iclaprim affected the mRNA expression of virulence-encoding genes associated with exoproteins, adherence, and regulation • In vivo study in G. mellonella larvae challenged with S. aureus exhibited that iclaprim improves larvae survival.

Asunto(s)

Antibacterianos , Biopelículas , Larva , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas , Staphylococcus aureus , Factores de Virulencia , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/patogenicidad , Staphylococcus aureus/genética , Biopelículas/efectos de los fármacos , Animales , Factores de Virulencia/genética , Antibacterianos/farmacología , Virulencia/efectos de los fármacos , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/tratamiento farmacológico , Larva/microbiología , Mariposas Nocturnas/microbiología , Proteínas Hemolisinas/genética , Ácido Fólico/farmacología , Ácido Fólico/biosíntesis , Antagonistas del Ácido Fólico/farmacología , Coagulasa/metabolismo , Modelos Animales de Enfermedad , Pirimidinas

RESUMEN

Multi-resistant Staphylococcus aureus (S. aureus) infection is a significant global health concern owing to its high mortality and morbidity rates. Coagulase (Coa), a key enzyme that activates prothrombin to initiate host coagulation, has emerged as a promising target for anti-infective therapeutic approaches. This study identified sinigrin as a potent Coa inhibitor that significantly inhibited S. aureus-induced coagulation at concentration as low as 32 mg/L. Additionally, at a higher concentration of 128 mg/L, sinigrin disrupted the self-protection mechanism of S. aureus. Thermal shift and fluorescence-quenching assays confirmed the direct binding of sinigrin to the Coa protein. Molecular docking analysis predicted specific binding sites for sinigrin in the Coa molecule, and point mutation experiments highlighted the importance of Arg-187 and Asp-222 as critical binding sites for both Coa and sinigrin. In vivo studies demonstrated that the combination of sinigrin with oxacillin exhibited greater antibacterial efficacy than oxacillin alone in the treatment of S. aureus-induced pneumonia in mice. Furthermore, sinigrin was shown to reduce bacterial counts and inflammatory cytokine levels in the lung tissues of S. aureus-infected mice. In summary, sinigrin was shown to directly target Coa, resulting in the attenuation of S. aureus virulence, which suggests the potential of sinigrin as an adjuvant for future antimicrobial therapies.

Asunto(s)

Antibacterianos , Coagulasa , Simulación del Acoplamiento Molecular , Infecciones Estafilocócicas , Staphylococcus aureus , Coagulasa/metabolismo , Animales , Ratones , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/patogenicidad , Staphylococcus aureus/enzimología , Virulencia/efectos de los fármacos , Antibacterianos/farmacología , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/tratamiento farmacológico , Modelos Animales de Enfermedad , Citocinas/metabolismo , Oxacilina/farmacología , Sitios de Unión , Coagulación Sanguínea/efectos de los fármacos , Pulmón/microbiología , Pulmón/patología , Femenino , Ratones Endogámicos BALB C

RESUMEN

The Staphylococcus intermedius group (SIG) includes coagulase-positive staphylococci commonly found in animals. The taxonomic classification within the SIG has evolved with molecular techniques distinguishing five species. Despite their similarities, these species exhibit varied host affinities, with unclear implications for virulence and host interaction. This study aimed to investigate the presence of coagulase-positive staphylococci in pigeons and to detect genes encoding for selected virulence factors in isolated strains. Another goal was to determine the adhesion capabilities of randomly selected pigeon S. intermedius, S. delphini, and canine S. pseudintermedius strains to canine and pigeon corneocytes and their adhesion and invasion abilities to canine keratinocytes in vitro. In total, 121 coagulase-positive strains were isolated from domestic and feral pigeons. The most prevalent species were S. delphini B and S. intermedius in domestic and feral pigeons, respectively. We proved that pigeon strains carried genes encoding for exfoliative toxin SIET and leukotoxin Luk-I. Moreover, we found that S. intermedius showed higher adherence to pigeon than to canine corneocytes, aligning with its presumed natural host. No difference in adherence abilities of S. pseudintermedius to canine and pigeon corneocytes was observed. In this study, we also observed that S. pseudintermedius could successfully invade the canine keratinocytes, in contrary to S. delphini and S. intermedius. Moreover, only S. intermedius was not able to invade canine keratinocytes at all. These findings highlight the complex interplay between SIG bacteria, and their hosts, underscoring the need for further research to understand the mechanisms of host adaptation and pathogenicity within this group.

Asunto(s)

Adhesión Bacteriana , Columbidae , Especificidad del Huésped , Queratinocitos , Infecciones Estafilocócicas , Staphylococcus intermedius , Staphylococcus , Factores de Virulencia , Animales , Columbidae/microbiología , Perros , Factores de Virulencia/genética , Staphylococcus/genética , Staphylococcus/patogenicidad , Staphylococcus/clasificación , Staphylococcus/aislamiento & purificación , Queratinocitos/microbiología , Virulencia/genética , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/veterinaria , Staphylococcus intermedius/genética , Staphylococcus intermedius/patogenicidad , Coagulasa/metabolismo , Coagulasa/genética , Exfoliatinas/genética , Exfoliatinas/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo

RESUMEN

BACKGROUND: Coagulase-negative Staphylococcus species are an emerging cause of intramammary infection, posing a significant economic and public health threat. The aim of this study was to assess the occurrence of coagulase-negative Staphylococcus species in bovine milk and dairy farms in Northwestern Ethiopia and to provide information about their antibiotic susceptibility and virulence gene profiles. METHODS: The cross-sectional study was conducted from February to August 2022. Coagulase-negative Staphylococcus species were isolated from 290 milk samples. Species isolation and identification were performed by plate culturing and biochemical tests and the antimicrobial susceptibility pattern of each isolate was determined by the Kirby-Bauer disc diffusion test. The single-plex PCR was used to detect the presence of virulent genes. The STATA software version 16 was used for data analysis. The prevalence, proportion of antimicrobial resistance and the number of virulent genes detected from coagulase-negative Staphylococcus species were analyzed using descriptive statistics. RESULTS: Coagulase-negative Staphylococcus species were isolated in 28.6%, (95% CI: 23.5-34.2) of the samples. Of these, the S. epidermidis, S. sciuri, S. warneri, S. haemolyticus, S. simulans, S. chromogens, S. cohnii, and S. captis species were isolated at the rates of 11, 5.2, 3.4, 3.1, 3.1, 1, 1, and 0.7% respectively. All the isolates showed a high percentage (100%) of resistance to Amoxicillin, Ampicillin, and Cefotetan and 37.5% of resistance to Oxacillin. The majority (54.2%) of coagulase-negative isolates also showed multidrug resistance. Coagulase-negative Staphylococcus species carried the icaD, pvl, mecA, hlb, sec, and hla virulent genes at the rates of 26.5%, 22.1%, 21.7%, 9.6%, 9.6% and 8.4% respectively. CONCLUSION: The present study revealed that the majority of the isolates (54.2%) were found multidrug-resistant and carriage of one or more virulent and enterotoxin genes responsible for intramammary and food poisoning infections. Thus, urgent disease control and prevention measures are warranted to reduce the deleterious impact of coagulase-negative species. To the best of our knowledge, this is the first study in Ethiopia to detect coagulase-negative Staphylococcus species with their associated virulent and food poisoning genes from bovine milk.

Asunto(s)

Antibacterianos , Coagulasa , Pruebas de Sensibilidad Microbiana , Leche , Staphylococcus , Animales , Leche/microbiología , Bovinos , Staphylococcus/genética , Staphylococcus/efectos de los fármacos , Staphylococcus/aislamiento & purificación , Staphylococcus/enzimología , Etiopía , Coagulasa/genética , Coagulasa/metabolismo , Estudios Transversales , Antibacterianos/farmacología , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/veterinaria , Virulencia/genética , Factores de Virulencia/genética , Femenino , Genes Bacterianos/genética , Mastitis Bovina/microbiología

RESUMEN

Bacterial adhesins are cell-surface proteins that anchor to the cell wall of the host. The first stage of infection involves the specific attachment to fibrinogen (Fg), a protein found in human blood. This attachment allows bacteria to colonize tissues causing diseases such as endocarditis. The study of this family of proteins is hence essential to develop new strategies to fight bacterial infections. In the case of the Gram-positive bacterium Staphylococcus aureus, there exists a class of adhesins known as microbial surface components recognizing adhesive matrix molecules (MSCRAMMs). Here, we focus on one of them, the clumping factor A (ClfA), which has been found to bind Fg through the dock-lock-latch mechanism. Interestingly, it has recently been discovered that MSCRAMM proteins employ a catch-bond to withstand forces exceeding 2 nN, making this type of interaction as mechanically strong as a covalent bond. However, it is not known whether this strength is an evolved feature characteristic of the bacterial protein or is typical only of the interaction with its partner. Here, we combine single-molecule force spectroscopy, biophysical binding assays, and molecular simulations to study the intrinsic mechanical strength of ClfA. We find that despite the extremely high forces required to break its interactions with Fg, ClfA is not by itself particularly strong. Integrating the results from both theory and experiments we dissect contributions to the mechanical stability of this protein.

Asunto(s)

Coagulasa , Fibrinógeno , Staphylococcus aureus , Staphylococcus aureus/metabolismo , Staphylococcus aureus/química , Coagulasa/metabolismo , Coagulasa/química , Fibrinógeno/química , Fibrinógeno/metabolismo , Unión Proteica , Adhesinas Bacterianas/metabolismo , Adhesinas Bacterianas/química , Humanos , Estabilidad Proteica

RESUMEN

Coagulase-negative Staphylococcus (CoNS) species inhibiting Staphylococcus aureus has been described in the skin of atopic dermatitis (AD) patients. This study evaluated whether Staphylococcus spp. from the skin and nares of AD and non-AD children produced antimicrobial substances (AMS). AMS production was screened by an overlay method and tested against NaOH, proteases and 30 indicator strains. Clonality was assessed by pulsed-field gel electrophoresis. Proteinaceous AMS-producers were investigated for autoimmunity by the overlay method and presence of bacteriocin genes by polymerase chain reaction. Two AMS-producers had their genome screened for AMS genes. A methicillin-resistant S. aureus (MRSA) produced proteinaceous AMS that inhibited 51.7% of the staphylococcal indicator strains, and it was active against 60% of the colonies selected from the AD child where it was isolated. On the other hand, 57 (8.8%) CoNS from the nares and skin of AD and non-AD children, most of them S. epidermidis (45.6%), reduced the growth of S. aureus and other CoNS species. Bacteriocin-related genes were detected in the genomes of AMS-producers. AMS production by CoNS inhibited S. aureus and other skin microbiota species from children with AD. Furthermore, an MRSA colonizing a child with AD produced AMS, reinforcing its contribution to dysbiosis and disease severity.

Asunto(s)

Coagulasa , Dermatitis Atópica , Staphylococcus aureus Resistente a Meticilina , Microbiota , Piel , Staphylococcus , Dermatitis Atópica/microbiología , Humanos , Staphylococcus aureus Resistente a Meticilina/genética , Piel/microbiología , Niño , Coagulasa/genética , Coagulasa/metabolismo , Staphylococcus/genética , Bacteriocinas/genética , Antibacterianos/farmacología , Preescolar , Pruebas de Sensibilidad Microbiana

RESUMEN

Pet food have been considered as possible vehicles of bacterial pathogens. The sudden boom of the pet food industry due to the worldwide increase in companion animal ownership calls for pet food investigations. Herein, this study aimed to determine the frequency, antimicrobial susceptibility profile, and molecular characteristics of coagulase-negative staphylococci (CoNS) in different pet food brands in Brazil. Eighty-six pet food packages were screened for CoNS. All isolates were identified at species level by MALDI-TOF MS and species-specific PCR. Antimicrobial susceptibility testing was performed by disc diffusion and broth microdilution (vancomycin and teicoplanin only) methods. The D-test was used to screen for inducible clindamycin phenotype (MLS-B). SCCmec typing and detection of mecA, vanA, vanB, and virulence-encoding genes were done by PCR. A total of 16 (18.6 %) CoNS isolates were recovered from pet food samples. Isolates were generally multidrug-resistant (MDR). All isolates were completely resistant (100 %) to penicillin. Resistances (12.5 % - 75 %) were also observed for fluoroquinolones, sulfamethoxazole-trimethoprim, tetracycline, rifampicin, erythromycin, and tobramycin. Isolates were susceptible to vancomycin (MICs <0.25-1 µg/mL) and teicoplanin (MICs <0.25-4 µg/mL). Intriguingly, 3/8 (37.5 %) CoNS isolates with the ERYRCLIS antibiotype expressed MLS-B phenotype. All isolates harboured blaZ gene. Seven (43.8 %) isolates carried mecA; and among them, the SCCmec Type III was the most frequent (n = 5/7; 71.4 %). Isolates also harboured seb, see, seg, sej, sem, etb, tsst, pvl, and hla toxin virulence-encoding genes (6.3 % - 25 %). A total of 12/16 (75 %) isolates were biofilm producers, while the icaAB gene was detected in an S. pasteuri isolate. Herein, it is shown that pet food is a potential source of clinically important Gram-positive bacterial pathogens. To the best of our knowledge, this is the first report of MLS-B phenotype and MR-CoNS in pet food in Latin America.

Asunto(s)

Antibacterianos , Clindamicina , Coagulasa , Pruebas de Sensibilidad Microbiana , Staphylococcus , Staphylococcus/efectos de los fármacos , Staphylococcus/genética , Staphylococcus/aislamiento & purificación , Brasil , Antibacterianos/farmacología , Coagulasa/metabolismo , Animales , Clindamicina/farmacología , Meticilina/farmacología , Alimentación Animal/microbiología , Microbiología de Alimentos , Mascotas/microbiología , Farmacorresistencia Bacteriana Múltiple/genética

RESUMEN

BACKGROUND: Recently, linezolid-resistant staphylococci have become an emerging problem worldwide. Understanding the mechanisms of resistance, molecular epidemiology and transmission of linezolid-resistant CoNS in hospitals is very important. METHODS: The antimicrobial susceptibilities of all isolates were determined by the microdilution method. The resistance mechanisms and molecular characteristics of the strains were determined using whole-genome sequencing and PCR. RESULTS: All the strains were resistant to oxacillin and carried the mecA gene; 13 patients (36.1%) had prior linezolid exposure. Most S. epidermidis and S. hominis isolates were ST22 and ST1, respectively. MLST typing and evolutionary analysis indicated most linezolid-resistant CoNS strains were genetically related. In this study, we revealed that distinct CoNS strains have different mechanisms of linezolid resistance. Among ST22-type S. epidermidis, acquisition of the T2504A and C2534T mutations in the V domain of the 23 S rRNA gene, as well as mutations in the ribosomal proteins L3 (L101V, G152D, and D159Y) and L4 (N158S), were linked to the development of linezolid resistance. In S. cohnii isolates, cfr, S158Y and D159Y mutations in the ribosomal protein L3 were detected. Additionally, emergence of the G2576T mutation and the cfr gene were major causes of linezolid resistance in S. hominis isolates. The cfr gene, G2576T and C2104T mutations, M156T change in L3 protein, and I188S change in L4 protein were found in S. capitis isolates. CONCLUSION: The emergence of linezolid-resistant CoNS in the environment is concerning because it involves clonal dissemination and frequently coexists with various drug resistance mechanisms.

Asunto(s)

Antibacterianos , Linezolid , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas , Centros de Atención Terciaria , Linezolid/farmacología , Humanos , China/epidemiología , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/epidemiología , Antibacterianos/farmacología , Femenino , Masculino , Persona de Mediana Edad , Tipificación de Secuencias Multilocus , Anciano , Secuenciación Completa del Genoma , Staphylococcus/efectos de los fármacos , Staphylococcus/genética , Staphylococcus/clasificación , Staphylococcus/enzimología , Coagulasa/metabolismo , Coagulasa/genética , ARN Ribosómico 23S/genética , Adulto , Resistencia a la Meticilina/genética , Mutación , Proteínas Bacterianas/genética

RESUMEN

Milk is a source of essential nutrients, but food safety across the milk supply chain has emerged as an integral part of food trade. Of the several food safety hazards, antimicrobial-resistant Staphylococcus species have emerged as one of the major microbial hazards with significant public health concerns. The present crosssectional study was undertaken with the objective to isolate Staphylococcus species from the milk supply chain, characterize isolates for antimicrobial resistance, and trace the origin of isolates using molecular techniques. Samples collected from the formal and informal milk supply chains showed prevalence of Staphylococcus species of 4.3% (n=720); isolates were identified as coagulase-positive (S. aureus 67.7% and S. intermedius 6.4%) and coagulase-negative (S. lentus 9.6%, S. sciuri 3.2%, S. xylosus 3.2%, S. schleiferi 3.2%, S. felis 3.2%, and S. gallinarum 3.2%) species. Staphylococcus isolates showed antimicrobial resistance to methicillin (32.2%), ß-lactam (41.9%), and macrolide-lincosamide-streptogramin B (3.2%). Staphylococcus isolates phenotypically resistant to methicillin also carried the mecA gene and displayed diverse pulsed field gel electrophoresis (PFGE) profiles, indicating their diverse origins in the milk supply chain. Based on the similarity of PFGE profile, the origin of one of the Staphylococcus isolates was traced to the soil in contact with milch cows. The findings of this study highlight the need for more comprehensive microbial risk analysis studies across the milk supply chain, capacity building, creation of awareness among stakeholders about the judicious use of antimicrobials, and protection of public health using a One-Health approach.

Asunto(s)

Antibacterianos , Leche , Staphylococcus , Leche/microbiología , Animales , Staphylococcus/efectos de los fármacos , Staphylococcus/genética , Staphylococcus/aislamiento & purificación , Antibacterianos/farmacología , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/epidemiología , Microbiología de Alimentos , Humanos , Bovinos , Proteínas Bacterianas/genética , Coagulasa/genética , Coagulasa/metabolismo , Farmacorresistencia Bacteriana/genética

RESUMEN

This study was condcuted to examine the association of area under the curve (AUC)/minimum inhibitory concentration (MIC) and trough concentration (Ctrough) of vancomycin with treatment outcome and nephrotoxicity in infections caused by Enterococcus spp. and coagulase-negative Staphylococci (CoNS). Peak and trough concentrations were used to calculate AUC in 89 patients receiving vancomycin for infections with Enterococcus spp. (n = 65) or CoNS (n = 24). Correlations between Ctrough, AUC/MIC, early clinical response (ECR), and nephrotoxicity were assessed and cutoff values were determined. Sixty-three (70.8%) patients showed improvement in ECR and 10 (11.2%) experienced nephrotoxicity. Enterococcus spp. infections displayed correlations between AUC/MIC and ECR for AUC0-24 h/MIC (r2 = 0.27, P ≤ .05) and AUC24-48 h/MIC (r2 = 0.28, P ≤ .05), but not for Ctrough (r2 = 0.21, P > .05). There were no correlations between Ctrough (r2 = 0.26, P > .05), AUC0-24 h/MIC (r2 = -0.12, P > .05), AUC24-48 h/MIC (r2 = 0.01, P > .05) and ECR for CoNS. In the CoNS group, a moderate correlation was found between ECR and Ctrough at a cutoff value of 6.9 µg/mL. In addition, nephrotoxicity is also moderately associated with AUC0-24 h and AUC24-48 h at 505.7 and 667.1 µg•h/mL, respectively. A strong correlation between nephrotoxicity and Ctrough was observed when the cutoff value was 18.9 µg/mL. AUC/MIC during the first 48 h was a determinant of vancomycin efficacy in Enterococcus infections but not for CoNS. Ctrough was not correlated with clinical outcome. Nephrotoxicity could be predicted using Ctrough and AUC for infections with both pathogens.

Asunto(s)

Antibacterianos , Área Bajo la Curva , Enterococcus , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas , Staphylococcus , Vancomicina , Humanos , Masculino , Femenino , Vancomicina/farmacocinética , Vancomicina/efectos adversos , Vancomicina/sangre , Vancomicina/administración & dosificación , Vancomicina/uso terapéutico , Antibacterianos/farmacocinética , Antibacterianos/efectos adversos , Antibacterianos/administración & dosificación , Antibacterianos/sangre , Antibacterianos/uso terapéutico , Persona de Mediana Edad , Staphylococcus/efectos de los fármacos , Estudios Prospectivos , Anciano , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/microbiología , Enterococcus/efectos de los fármacos , Adulto , Infecciones por Bacterias Grampositivas/tratamiento farmacológico , Coagulasa/metabolismo , Resultado del Tratamiento , Anciano de 80 o más Años

RESUMEN

Since September 2018, serious meningitis has been found on some breeding-duck farms in Shandong Province, China. A large number of ducks exhibit severe neurological symptoms. The ducks were randomly selected for laboratory testing. Duck brain samples were collected using standard sterile techniques, and the staphylococci isolates were detected in 404 (70.14%) out of 576 brain samples. A total of 525 coagulase-negative staphylococci (CoNS) strains were isolated, including 6 species: Staphylococcus sciuri (S. sciuri) (67.24%, 353/525), Staphylococcus epidermidis (S. epidermidis) (9.71%, 51/525), Staphylococcus saprophyticus (S. saprophyticus) (8.38%, 44/525), Staphylococcus lentus (S. lentus) (7.62%, 40/525), Staphylococcus haemolyticus (S. haemolyticus) (2.48%, 13/525), and Staphylococcus xylosus (S. xylosus) (4.57%, 24/525). Mixed strain infections were detected in 121 (29.95%) infected presentations. The antimicrobial susceptibility testing indicated that 40.38% of the isolates exhibited multi-drug resistance, and 53.90% of the strains were methicillin-resistant strains by amplification of the methicillin resistance gene (mecA) gene. Through experimental reproduction of the disease, we determined that the CoNS strains were the leading pathogens causing bacterial meningitis in ducks. Although these CoNS strains does not directly cause the death of sick ducks, they still cause large economic losses due to the retarded growth and development of the sick ducks, lower feed returns, and lower grades of processed duck products. The results of this study will contribute to our understanding of the epidemiology and pathogenesis of CoNS and be helpful in the prevention and treatment of the infection.

Asunto(s)

Coagulasa , Patos , Meningitis Bacterianas , Enfermedades de las Aves de Corral , Infecciones Estafilocócicas , Staphylococcus , Animales , Staphylococcus/efectos de los fármacos , Staphylococcus/aislamiento & purificación , Staphylococcus/enzimología , Enfermedades de las Aves de Corral/microbiología , Enfermedades de las Aves de Corral/epidemiología , Infecciones Estafilocócicas/veterinaria , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/epidemiología , Coagulasa/metabolismo , Meningitis Bacterianas/veterinaria , Meningitis Bacterianas/microbiología , Meningitis Bacterianas/epidemiología , China/epidemiología , Antibacterianos/farmacología

RESUMEN

PURPOSE: Coagulase-negative staphylococci (CoNS) are Gram-positive organisms that are a known component of normal skin flora and the most common cause of nosocomial bacteremia. For CoNS species, the vancomycin MIC breakpoint for susceptibility set by the Clinical and Laboratory Standards Institute is ≤4 µg/mL. There has been published reports of vancomycin heteroresistance in CoNS with vancomycin MICs of 2 to 4 µg/mL. The aim of this retrospective cohort analysis was to assess the clinical impact of vancomycin MICs <2 µg/mL versus ≥2 µg/mL in adult patients with CoNS bloodstream infections. METHODS: Adult patients admitted to University Medical Center New Orleans with a blood culture positive for CoNS were assessed. The primary outcome was difference in 30-day mortality. Secondary outcomes were in-hospital, all-cause mortality; duration of bacteremia; hospital length of stay; and percentage of oxacillin-resistant CoNS. FINDINGS: There was no difference in mortality in the vancomycin MIC <2 µg/mL group versus the vancomycin MIC ≥2 µg/mL group at 30 days (15.4% vs 17.4%; P = 1). In-hospital, all-cause mortality was also not different between groups (11.5% vs 13%; P = 1). Hospital length of stay between groups was 28.2 days versus 21 days (P = 0.692). Median duration of bacteremia was 1 day in both groups (P = 0.975), and median scheduled duration of antibiotic therapy was 14.9 days and 19.5 days (P = 0.385). The source and mode of acquisition of CoNS were similar between groups. Of all CoNS isolates, 58.7% (44 of 75) were oxacillin resistant. Staphylococcus epidermidis was the most common CoNS species at 66.7% (50 of 75). Of all isolates, 30.7% (23 of 75) had a vancomycin MIC ≥2 µg/mL, and 87% (20 of 23) of these were S. epidermidis. There was a higher percentage of S. epidermidis in the vancomycin MIC ≥2 µg/mL group than in the MIC <2 µg/mL group (87% vs 57.7%; P = 0.012). CoNS with a vancomycin MIC ≥2 µg/mL were also more likely to be oxacillin resistant (78.3% vs 50%; P = 0.005). IMPLICATIONS: There was no difference in clinical outcomes in adult patients with a CoNS bloodstream infection with a vancomycin MIC <2 µg/mL versus ≥2 µg/mL. At present, vancomycin remains appropriate empiric therapy for CoNS bloodstream infection. Further research is needed to determine if there is a true clinical impact of a vancomycin MIC ≥2 µg/mL in CoNS infections.

Asunto(s)

Antibacterianos , Bacteriemia , Coagulasa , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas , Staphylococcus , Vancomicina , Humanos , Vancomicina/uso terapéutico , Vancomicina/farmacología , Bacteriemia/tratamiento farmacológico , Bacteriemia/microbiología , Bacteriemia/mortalidad , Masculino , Estudios Retrospectivos , Femenino , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/microbiología , Persona de Mediana Edad , Antibacterianos/uso terapéutico , Antibacterianos/farmacología , Coagulasa/metabolismo , Staphylococcus/efectos de los fármacos , Staphylococcus/aislamiento & purificación , Anciano , Resultado del Tratamiento , Adulto , Tiempo de Internación/estadística & datos numéricos

RESUMEN

The species- and clone-specific susceptibility of Staphylococcus cells for bacteriophages is governed by the structures and glycosylation patterns of wall teichoic acid (WTA) glycopolymers. The glycosylation-dependent phage-WTA interactions in the opportunistic pathogen Staphylococcus epidermidis and in other coagulase-negative staphylococci (CoNS) have remained unknown. We report a new S. epidermidis WTA glycosyltransferase TagE whose deletion confers resistance to siphoviruses such as ΦE72 but enables binding of otherwise unbound podoviruses. S. epidermidis glycerolphosphate WTA was found to be modified with glucose in a tagE-dependent manner. TagE is encoded together with the enzymes PgcA and GtaB providing uridine diphosphate-activated glucose. ΦE72 transduced several other CoNS species encoding TagE homologs, suggesting that WTA glycosylation via TagE is a frequent trait among CoNS that permits interspecies horizontal gene transfer. Our study unravels a crucial mechanism of phage-Staphylococcus interaction and horizontal gene transfer, and it will help in the design of anti-staphylococcal phage therapies.IMPORTANCEPhages are highly specific for certain bacterial hosts, and some can transduce DNA even across species boundaries. How phages recognize cognate host cells remains incompletely understood. Phages infecting members of the genus Staphylococcus bind to wall teichoic acid (WTA) glycopolymers with highly variable structures and glycosylation patterns. How WTA is glycosylated in the opportunistic pathogen Staphylococcus epidermidis and in other coagulase-negative staphylococci (CoNS) species has remained unknown. We describe that S. epidermidis glycosylates its WTA backbone with glucose, and we identify a cluster of three genes responsible for glucose activation and transfer to WTA. Their inactivation strongly alters phage susceptibility patterns, yielding resistance to siphoviruses but susceptibility to podoviruses. Many different CoNS species with related glycosylation genes can exchange DNA via siphovirus ΦE72, suggesting that glucose-modified WTA is crucial for interspecies horizontal gene transfer. Our finding will help to develop antibacterial phage therapies and unravel routes of genetic exchange.

Asunto(s)

Infecciones Estafilocócicas , Staphylococcus epidermidis , Humanos , Staphylococcus epidermidis/genética , Staphylococcus epidermidis/metabolismo , Staphylococcus aureus/genética , Coagulasa/metabolismo , Glucosa/metabolismo , Ácidos Teicoicos/metabolismo , Staphylococcus/metabolismo , Fagos de Staphylococcus/genética , ADN/metabolismo , Pared Celular/metabolismo , Infecciones Estafilocócicas/metabolismo

RESUMEN

Staphylococcus schleiferi and Staphylococcus coagulans are opportunistic pathogens of animals and humans. They were previously classified as Staphylococcus schleiferi subs. schleiferi and Staphylococcus schleiferi subs. coagulans, respectively, and recently reclassified as separate species. S. coagulans, is frequently associated with dogs, whereas S. schleiferi is more commonly isolated from humans. Coagulase activity status is a defining characteristic of the otherwise closely related species. However, the use of coagulase tests originally developed to distinguish S. aureus from non-coagulase-producing staphylococci, for this purpose is questionable and the basis for their host preference has not been elucidated. In the current study, a putative coa gene was identified and correlated with coagulase activity measured using a chromogenic assay with human and bovine prothrombin (closely related to canine prothrombin). The results of the tests performed with human prothrombin showed greater reactivity of S. coagulans isolates from humans than isolates obtained from dogs with the same substrate. Our data suggest that unlike S. coagulans isolates from humans, isolates from dogs have more coagulase activity with bovine prothrombin (similar to canine prothrombin) than human prothrombin. Differences in nuc and 16s rRNA genes suggest a divergence in S. coagulans and S. schleiferi. Phenotypic and genotypic variation based on the number of IgG binding domains, and the numbers of tandem repeats in C-terminal fibronectin binding motifs was also found in protein A, and fibronectin-binding protein B respectively. This study identified a coa gene and associated phenotypic activity that differentiates S. coagulans and S. schleiferi and identified key phylogenetic and phenotypic differences between the species.

Asunto(s)

Enfermedades de los Perros , Infecciones Estafilocócicas , Animales , Humanos , Perros , Bovinos , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Coagulasa/genética , Coagulasa/metabolismo , ARN Ribosómico 16S/genética , Fibronectinas/genética , Filogenia , Protrombina , Staphylococcus/metabolismo , Infecciones Estafilocócicas/veterinaria

RESUMEN

BACKGROUND: Venous access device-related bloodstream infection (VAD-BSI) with coagulase-negative staphylococci (CoNS) is a common complication after allogeneic hematopoietic cell transplantation (alloHCT). Standard systemic antimicrobial therapy for uncomplicated VAD-BSI with methicillin-resistant CoNS consists of intravenous (IV) vancomycin (vanco). This requires hospitalization, needs new competent venous access, exposes patients to potential toxicity (mainly renal) and increases the risk of commensal flora dysbiosis with selection of vanco-resistant enterococci. Combined with VAD management (removal or antibiotic locks), oral minocycline (mino) has been evaluated as an alternative systemic therapy for the treatment of uncomplicated VAD-BSIs with CoNS at our center, primarily when the reference treatment with IV vanco was not possible (renal failure or allergy) or when hospitalization was refused by patients. Here, we retrospectively report our single center experience with this mino-based approach. PATIENTS AND METHODS: From January 2012 to December 2020, 24 uncomplicated VAD-BSIs with CoNS in 23 alloHCT patients were treated with oral mino as systemic antibiotic therapy in combination with VAD management. VAD were implantable ports (n = 17), tunneled catheter (n = 1) or PIC-lines (n = 6). Staphylococci were S. epidermidis (n = 21) or S. haemolyticus (n = 3). Mino was administered with a loading dose of 200 mg followed by 100 mg BID for 7-14 days. For 8 VAD-BSIs, patients were initially treated with IV vanco for the first 1-3 days followed by oral mino, while 16 VAD-BSIs were treated with oral mino as the sole antimicrobial agent for systemic therapy. VAD management consisted of catheter removal (for tunneled catheters and PIC-lines, n = 7) or antibiotic locks with vanco (n = 15) or gentamicin (n = 2) administered at least 3 times a week for 14 days (for ports). RESULTS: Overall, clearance of bacteremia (as assessed by negativity for the same CoNS of surveillance peripheral blood cultures drawn between day+ 3 and +30 after initiation of systemic therapy) was achieved in all but 1 patient (with port) who had persistent bacteremia at day +9. No complication such as suppurative thrombophlebitis, endocarditis, distant foci of infection or BSI-related death was observed in any patient during the 3-month period after initiation of treatment. Regarding the 17 port-BSI cases for which VAD conservative strategy was attempted, failure of 3-month VAD preservation was documented in 7/17 cases and 3-month recurrence of VAD-BSI was observed in 3/17 cases (with 1 patient with cellulitis). Treatment with mino was well tolerated except for a mild skin rash in one patient. CONCLUSION: Further prospective studies are needed to evaluate efficacy and safety of this approach.

Asunto(s)

Bacteriemia , Infecciones Relacionadas con Catéteres , Trasplante de Células Madre Hematopoyéticas , Infecciones Estafilocócicas , Humanos , Minociclina/uso terapéutico , Coagulasa/metabolismo , Coagulasa/uso terapéutico , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/etiología , Estudios Retrospectivos , Infecciones Relacionadas con Catéteres/tratamiento farmacológico , Infecciones Relacionadas con Catéteres/epidemiología , Staphylococcus/metabolismo , Antibacterianos/efectos adversos , Vancomicina/uso terapéutico , Bacteriemia/tratamiento farmacológico , Bacteriemia/etiología , Bacteriemia/epidemiología , Trasplante de Células Madre Hematopoyéticas/efectos adversos

RESUMEN

Staphylococcus aureus (S. aureus) induces a variety of infectious diseases in humans and animals and is responsible for hospital- and community-acquired infections. The aim of this study was to investigate how bilobetin, a natural compound, attenuates S. aureus virulence by inhibiting two key virulence factors, von Willebrand factor-binding protein (vWbp) and staphylocoagulase (Coa). The results showed that bilobetin inhibited Coa- or vWbp-induced coagulation without affecting S. aureus proliferation. The Western blotting and fluorescence quenching assays indicated that bilobetin did not affect the expression of vWbp and Coa but directly bound to the proteins with KA values of 1.66 × 104 L/mol and 1.04 × 104 L/mol, respectively. To gain further insight into the mechanism of interaction of bilobetin with these virulence factors, we performed molecular docking and point mutation assays, which indicated that the TYR-6 and TYR-18 residues on vWbp and the ALA-190 and ASP-189 residues on Coa were essential for the binding of bilobetin. In addition, the in vivo studies showed that bilobetin ameliorated lung tissue damage and inflammation caused by S. aureus, thereby improving the survival of mice. Furthermore, the use of bilobetin as an adjuvant in combination with vancomycin was more effective in the treatment of a mouse model of pneumonia. Taken together, bilobetin had a dual inhibitory effect on vWbp and Coa by reducing the virulence of S. aureus, suggesting that it is a viable lead compound against S. aureus infections.

Asunto(s)

Coagulasa , Infecciones Estafilocócicas , Humanos , Ratones , Animales , Coagulasa/genética , Coagulasa/metabolismo , Coagulasa/farmacología , Proteínas Portadoras/metabolismo , Staphylococcus aureus , Virulencia , Factor de von Willebrand/metabolismo , Factor de von Willebrand/farmacología , Simulación del Acoplamiento Molecular , Infecciones Estafilocócicas/tratamiento farmacológico , Factores de Virulencia/genética , Factores de Virulencia/metabolismo

RESUMEN

Background: The objective of this study was to isolate Staphylococcus spp. and to characterize the resistance profile in nasal samples from pigs slaughtered for consumption. Material and Methods: Intranasal swabs were collected from 100 pigs immediately after bleeding in a slaughterhouse located in the largest pork production region in Brazil, these samples were cultured and isolated to identify Staphylococcus spp. in coagulase positive (CoPS) and coagulase negative (CoNS) and molecular identification of Staphylococcus aureus and then subjected to the disk-diffusion test to identify the bacterial resistance profile and search for the mecA gene. Results: Of the 100 samples collected, it was possible to isolate 79 Staphylococcus spp., of these, 72.15% were classified as CoNS and 27.85% of the isolates classified as CoPS. Among the CoPS isolates, 77.27% were identified as S. aureus. Through the disk-diffusion test, it was possible to verify isolates resistant to clindamycin and erythromycin (98.73%), chloramphenicol (93.67%), and doxycycline (89.87%). There was amplification of the mecA gene in 30.38% of Staphylococcus spp. Conclusion: The results of this study highlight the need for the careful use of antibiotics in swine production, in addition to aiming at continuous surveillance in relation to the rate of multiresistant microorganisms within these environments, focused on large industrial centers; such results also indicate the importance of understanding, through future studies, possible pathways to transmission of these microorganisms directly, or indirectly, through meat products derived from these pigs, which can be considered neglected diffusers of variants of Staphylococcus spp. resistant to antibiotics or carriers of important resistance genes related to One Health.

Asunto(s)

Infecciones Estafilocócicas , Enfermedades de los Porcinos , Animales , Porcinos , Staphylococcus/genética , Staphylococcus aureus/genética , Coagulasa/metabolismo , Proteínas Bacterianas/genética , Pruebas de Sensibilidad Microbiana/veterinaria , Antibacterianos/farmacología , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/veterinaria , Infecciones Estafilocócicas/microbiología , Enfermedades de los Porcinos/epidemiología

RESUMEN

The massive use of antibiotics has resulted in an alarming increase in antibiotic resistance in Staphylococcus aureus (S. aureus). This study aimed to identify the inhibitory effect of salicin on S. aureus. Coagulase (Coa) activity was assessed using in vitro Coa assays and Western blot, thermal shift assay (TSA), fluorescence quenching and molecular docking experiments were conducted to verify the interaction between salicin and Coa. An in vivo mouse pneumonia model demonstrated that salicin can reduce the virulence of S. aureus. In vitro Coa assays elucidated that salicin directly inhibited Coa activity. The Western blot and TSA results suggested that salicin did not block the expression of Coa but affected the thermal stability of the protein by binding to Coa. The fluorescence quenching, molecular docking and molecular dynamics assays have found that the most promising binding site between salicin and Coa was GLN-97. The pneumonia model of mice infected with S. aureus revealed that salicin could not only reduce the content of lung bacteria in mice but also prolong their survival. Salicin was identified as a novel anti-infective candidate compound with the potential to target Coa and inhibit its activity by binding to it, which would facilitate the development of roadmaps for future research.

Asunto(s)

Staphylococcus aureus Resistente a Meticilina , Neumonía , Infecciones Estafilocócicas , Animales , Ratones , Staphylococcus aureus , Coagulasa/metabolismo , Coagulasa/farmacología , Proteínas Bacterianas , Simulación del Acoplamiento Molecular , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/microbiología , Antibacterianos/farmacología

RESUMEN

Aim: Our primary objective was to investigate the protective effects and mechanisms of isovanillic acid in mice infected with Staphylococcus aureus Newman. Methods: In vitro coagulation assays were used to validate vWbp and Coa as inhibitory targets of isovanillic acid. The binding mechanism of isovanillic acid to vWbp and Coa was investigated using molecular docking and point mutagenesis. Importantly, a lethal pneumonia mouse model was used to assess the effect of isovanillic acid on survival and pathological injury in mice. Results & Conclusion: Isovanillic acid reduced the virulence of S. aureus by directly binding to inhibit the clotting activity of vWbp and Coa, thereby reducing lung histopathological damage and improving the survival rate in mice with pneumonia.

Asunto(s)

Coagulasa , Infecciones Estafilocócicas , Ratones , Animales , Coagulasa/metabolismo , Staphylococcus aureus/metabolismo , Simulación del Acoplamiento Molecular , Infecciones Estafilocócicas/prevención & control