RESUMEN

Background: Staphylococcus aureus infections are a significant cause of morbidity and mortality in pediatric populations worldwide. The Staphylo Research Network conducted an extensive study on pediatric patients across Colombia from 2018 to 2021. The aim of this study was to describe the epidemiological and microbiological characteristics of S. aureus in this patient group. Methods: We analyzed S. aureus isolates from WHONET-reporting centers. An "event" was a positive culture isolation in a previously negative individual after 2 weeks. We studied center characteristics, age distribution, infection type, and antibiotic susceptibilities, comparing methicillin sensitive (MSSA) and resistant S. aureus (MRSA) isolates. Results: Isolates from 20 centers across 7 Colombian cities were included. Most centers (80%) served both adults and children, with 55% offering oncology services and 85% having a PICU. We registered 8,157 S. aureus culture isolations from 5,384 events (3,345 MSSA and 1,961 MRSA) in 4,821 patients, with a median age of 5 years. Blood (26.2%) and skin/soft tissue (18.6%) were the most common infection sources. Most isolates per event remained susceptible to oxacillin (63.2%), clindamycin (94.3%), and TMP-SMX (98.3%). MRSA prevalence varied by city (<0.001), with slightly higher rates observed in exclusively pediatric hospitals. In contrast, the MRSA rate was somewhat lower in centers with Antimicrobial Stewardship Program (ASP). MRSA was predominantly isolated from osteoarticular infections and multiple foci, while MSSA was more frequently associated with recurrent infections compared to MRSA. Conclusions: This is the largest study of pediatric S. aureus infections in Colombia. We found MSSA predominance, but resistance have important regional variations. S. aureus remains susceptible to other commonly used antibiotics such as TMP-SMX and clindamycin. Ongoing monitoring of S. aureus infections is vital for understanding their behavior in children. Prospective studies within the Staphylored LATAM are underway for a more comprehensive clinical and genetic characterization.

RESUMEN

Infections caused by methicillin-susceptible Staphylococcus aureus (MSSA) are still associated with significant morbidity and mortality. Treatment failures of cefazolin (CFZ) have been reported and probably related to the inoculum effect. New treatments for severe MSSA infections are needed and ceftaroline fosamil (CPT) could be an option. Our aim was to describe the clinical characteristics of five patients with complicated MSSA bacteremia failing CFZ and successfully treated with CPT. We performed a retrospective chart review in a Hospital in Buenos Aires, Argentina; in a 12-month period, five patients (24%) of 21 with MSSA bacteremia experienced CFZ failure and were salvaged with CPT. The median time of CFZ therapy was 10 days before changing to CPT; four patients had evidence of metastatic spread and 2 had endocarditis. All patients experienced microbiological and clinical cure with CPT, which was used as monotherapy in 4 and in combination with daptomycin in another. One patient discontinued CPT due to neutropenia on day 23 of treatment. In patients with MSSA BSI failing current therapy, CPT could be a good therapeutic option.

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Las infecciones causadas por Staphylococcus aureus sensible a la meticilina (SASM) todavía se asocian con una morbilidad y mortalidad significativas. Se han informado fallas en el tratamiento de cefazolina (CFZ) probablemente relacionadas con efecto inóculo. Nuevos tratamientos son necesarios para estas infecciones y ceftarolina fosamil (CPT) podría ser una opción. Nuestro objetivo fue describir las características clínicas de cinco pacientes con bacteriemia por SASM complicada con falla a CFZ y que fueron exitosamente tratados con CPT. Realizamos una revisión retrospectiva de historias clínicas en un hospital de Buenos Aires, Argentina; en un período de 12 meses, cinco pacientes (24%) de 21 con bacteriemia por SASM experimentaron falla a CFZ y fueron tratados con CPT. La mediana de tiempo de la terapia con CFZ fue de 10 días antes de cambiar a CPT; cuatro pacientes presentaban evidencia de diseminación metastásica y 2 tenían endocarditis. Todos los pacientes experimentaron curación microbiológica y clínica con CPT, que se utilizó como monoterapia en 4 y en combinación con daptomicina en otro. Un paciente interrumpió CPT debido a neutropenia el día 23 de tratamiento. En enfermos con infecciones graves por SASM que fallan en la terapia actual, CPT podría ser una buena opción terapéutica.

Asunto(s)

Bacteriemia , Daptomicina , Infecciones Estafilocócicas , Antibacterianos/uso terapéutico , Bacteriemia/tratamiento farmacológico , Bacteriemia/microbiología , Cefazolina/uso terapéutico , Cefalosporinas , Daptomicina/uso terapéutico , Humanos , Meticilina/uso terapéutico , Estudios Retrospectivos , Terapia Recuperativa , Infecciones Estafilocócicas/complicaciones , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus , Ceftarolina

RESUMEN

Abstract Infections caused by methicillin-susceptible Staphylococcus aureus (MSSA) are still associated with significant morbidity and mortality. Treatment failures of cefazolin (CFZ) have been reported and probably related to the inoculum effect. New treatments for severe MSSA infections are needed and ceftaroline fosamil (CPT) could be an option. Our aim was to describe the clinical characteristics of five patients with com plicated MSSA bacteremia failing CFZ and successfully treated with CPT. We performed a retrospective chart review in a Hospital in Buenos Aires, Argentina; in a 12-month period, five patients (24%) of 21 with MSSA bacteremia experienced CFZ failure and were salvaged with CPT. The median time of CFZ therapy was 10 days before changing to CPT; four patients had evidence of metastatic spread and 2 had endocarditis. All patients experienced microbiological and clinical cure with CPT, which was used as monotherapy in 4 and in combination with daptomycin in another. One patient discontinued CPT due to neutropenia on day 23 of treatment. In patients with MSSA BSI failing current therapy, CPT could be a good therapeutic option.

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Resumen Las infecciones causadas por Staphylococcus aureus sensible a la meticilina (SASM) todavía se asocian con una morbilidad y mortalidad significativas. Se han informado fallas en el tratamiento de cefazolina (CFZ) probablemente relacionadas con efecto inóculo. Nuevos tratamientos son necesarios para estas infecciones y ceftarolina fosamil (CPT) podría ser una opción. Nuestro objetivo fue describir las características clínicas de cinco pacientes con bacteriemia por SASM complicada con falla a CFZ y que fueron exitosamente tratados con CPT. Realizamos una revisión retrospectiva de historias clínicas en un hospital de Buenos Aires, Argentina; en un período de 12 meses, cinco pacientes (24%) de 21 con bacteriemia por SASM experimentaron falla a CFZ y fueron tratados con CPT. La mediana de tiempo de la terapia con CFZ fue de 10 días antes de cambiar a CPT; cuatro pacientes presentaban evidencia de diseminación metastásica y 2 tenían endocarditis. Todos los pacientes experimen taron curación microbiológica y clínica con CPT, que se utilizó como monoterapia en 4 y en combinación con daptomicina en otro. Un paciente interrumpió CPT debido a neutropenia el día 23 de tratamiento. En enfermos con infecciones graves por SASM que fallan en la terapia actual, CPT podría ser una buena opción terapéutica.

RESUMEN

Aim: To find alternative compounds against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA), novel derivatives from dehydroabietic acid were synthesized. Methods & results: Compound 12 was the most effective against 15 MRSA and 11 MSSA with minimum inhibitory concentration values ranging from 3.9 to 15.6 µg/ml. Although less active than 12, compound 11, followed by 25 and 13, also exhibited anti-staphylococcal activity. Additional studies showed that compound 12 is devoid of toxic effect on non-target cells. A structure-activity relationship study revealed that an oxime at C-13 together with a hydroxyl at C-12 could play a key role in the activity. Conclusion: These structures, in particular compound 12, could arise as templates for the development of agents against MRSA and MSSA.

Asunto(s)

Abietanos/síntesis química , Antibacterianos/síntesis química , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Abietanos/química , Abietanos/farmacología , Abietanos/toxicidad , Antibacterianos/química , Antibacterianos/farmacología , Antibacterianos/toxicidad , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Aberraciones Cromosómicas/inducido químicamente , Eritrocitos/efectos de los fármacos , Hemólisis/efectos de los fármacos , Humanos , Leucocitos Mononucleares/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Cebollas/efectos de los fármacos , Cebollas/genética , Relación Estructura-Actividad

RESUMEN

The aim of this letter was to point out some methodological concerns about an article written by Shi et al. and published in the journal. There is an increasing trend in the isolation of Methicillin-susceptible Staphylococcus aureus bacteremia and a variety of questions regarding the best therapy to treat this condition. These concerns might lead to selection, publication and information bias that prevent the generalization and application of these results in our clinical practice.

Asunto(s)

Bacteriemia , Infecciones Estafilocócicas , Antibacterianos , Cefazolina , Humanos , Meticilina , Penicilinas , Staphylococcus aureus

RESUMEN

Staphylococcus aureus is a pathogen associated a different kind of infection. Molecular markers are useful tools to study microbial epidemiology. Twenty two methicillin-resistant S. aureus (MRSA) and 23 methicillin-susceptible S. aureus (MSSA) were studied by mecA gene, SCCmec cassette, Panton Valentine leucocidin (PVL) and spa polymorphism. The clinical data patients were analyzed. MSSA was prevalent in samples different from skin and soft tissue (SST) and in hospitalized patients, whereas MRSA in SST. SCCmec type IV was predominant, followed by type I. Low presence of PVL was found. In MRSA 11 different types of spa were detected, t019 was the most frequent and associated with outpatient, 17 types were found in MSSA and t189 was prevalent. spa t002 was present in MSSA and MRSA. We found 11 types of spa not reported in our country.

Asunto(s)

Hospitales , Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Staphylococcus aureus , Adulto , Antibacterianos , Argentina , Proteínas Bacterianas , Toxinas Bacterianas , Humanos , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Pruebas de Sensibilidad Microbiana

RESUMEN

INTRODUCTION: When clinicians think about Staphylococcus aureus bacteria, what comes to the mind of most is the dreaded methicillin-resistant form. However, clinicians should not forget the methicillin-susceptible type, which is just as virulent. CASE PRESENTATION: The authors present the case of a 20-year-old woman who was admitted with septic shock and multi-organ failure and was found to have disseminated methicillin-susceptible Staphylococcus aureus (MSSA) infection. The patient had persistent blood cultures positive for MSSA. A transesophageal echocardiogram showed a 1.1 cm vegetation in the mitral valve, and the patient had bilateral pleural effusions that grew MSSA. An MRI of the brain showed multiple areas consistent with infarctions thought to be secondary to septic emboli. The patient underwent a mitral valve replacement and was treated with a prolonged course of parenteral nafcillin. DISCUSSION: This case illustrates a severe clinical presentation and management of MSSA infections.

Asunto(s)

Meticilina/farmacología , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/aislamiento & purificación , Adulto , Antibacterianos/uso terapéutico , Femenino , Humanos , Nafcilina/uso terapéutico , Infecciones Estafilocócicas/diagnóstico , Staphylococcus aureus/efectos de los fármacos , Adulto Joven

RESUMEN

Introduction Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) have become common in hospitals and the community environment, and this wide resistance has limited patient treatment. Clindamycin (CL) represents an important alternative therapy for infections caused by S. aureus. Antimicrobial susceptibility testing using standard methods may not detect inducible CL resistance. This study was performed to detect the phenotypes of resistance to macrolides-lincosamides-streptogramin B (MLSB) antibiotics, including CL, in clinical samples of S. aureus from patients at a tertiary hospital in Santa Maria, State of Rio Grande do Sul, Brazil. Methods One hundred and forty clinical isolates were submitted to the disk diffusion induction test (D-test) with an erythromycin (ER) disk positioned at a distance of 20mm from a CL disk. The results were interpreted according to the recommendations of the Clinical and Laboratory Standards Institute (CLSI). Results In this study, 29 (20.7%) of the 140 S. aureus samples were resistant to methicillin (MRSA), and 111 (79.3%) were susceptible to methicillin (MSSA). The constitutive resistance phenotype (cMLSB) was observed in 20 (14.3%) MRSA samples and in 5 (3.6%) MSSA samples, whereas the inducible resistance phenotype (iMLSB) was observed in 3 (2.1%) MRSA samples and in 8 (5.8%) MSSA samples. Conclusions The D-test is essential for detecting the iMLSB phenotype because the early identification of this phenotype allows clinicians to choose an appropriate treatment for patients. Furthermore, this test is simple, easy to perform and inexpensive. .

Asunto(s)

Humanos , Antibacterianos/farmacología , Clindamicina/farmacología , Eritromicina/farmacología , Staphylococcus aureus/efectos de los fármacos , Farmacorresistencia Bacteriana Múltiple , Pruebas de Sensibilidad Microbiana , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Fenotipo , Staphylococcus aureus/genética , Staphylococcus aureus/aislamiento & purificación , Centros de Atención Terciaria

RESUMEN

OBJECTIVES: Although colonization traditionally is considered a risk factor for Staphylococcus aureus infection, the relationship between contemporary S aureus colonization and infection is not well characterized. We aimed to relate the presence of colonizing and disease-causing strains of S aureus within individuals and households. STUDY DESIGN: In a prospective study of 163 pediatric outpatients (cases) with community-associated S aureus skin and soft tissue infections in St Louis, infection isolates were obtained from cases and colonization cultures were obtained from cases and their household contacts (n = 562). Molecular typing by repetitive sequence-based polymerase chain reaction was used to compare infecting and colonizing isolates within each case. The infecting strain from each case was compared with S aureus strains colonizing household contacts. The colonization status of cases was followed for 12 months. RESULTS: A total of 27 distinct strain types were identified among the 1299 S aureus isolates evaluated. Between 1 and 6 distinct strain types were detected per household. A total of 110 cases (67%) were colonized at 1 or more body sites with the infecting strain. Of the 53 cases with an infecting strain that did not match a colonizing strain, 15 (28%) had 1 or more household contacts with a colonizing strain that matched the infecting strain. Intrafamilial strain-relatedness was observed in 105 families (64%). CONCLUSION: One-third of cases were colonized with a different strain type than the strain causing the skin and soft tissue infection. Fewer than one-third of cases with discordant infecting and colonizing isolates could be linked to the strain from another household contact, suggesting acquisition from sources outside the household.

Asunto(s)

Infecciones Comunitarias Adquiridas/epidemiología , ADN Bacteriano/genética , Composición Familiar , Piel/microbiología , Infecciones de los Tejidos Blandos/epidemiología , Infecciones Estafilocócicas/epidemiología , Staphylococcus aureus/genética , Adolescente , Niño , Preescolar , Infecciones Comunitarias Adquiridas/genética , Infecciones Comunitarias Adquiridas/microbiología , Femenino , Estudios de Seguimiento , Humanos , Incidencia , Lactante , Masculino , Reacción en Cadena de la Polimerasa , Estudios Prospectivos , Factores de Riesgo , Infecciones de los Tejidos Blandos/genética , Infecciones de los Tejidos Blandos/microbiología , Infecciones Estafilocócicas/genética , Staphylococcus aureus/aislamiento & purificación , Estados Unidos/epidemiología , Adulto Joven