Evaluation of different methods for detecting methicillin resistance in Staphylococcus aureus isolates in a university hospital located in the Northeast of Brazil

Júnior, Francisco Canindé de Sousa; Néri, Gildelane da Silva; Silva, Ana Karine; Araújo, Bibiana Priscila Rodrigues Câmara de; Guerra, Myrian Júlia de Paiva Dourado; Fernandes, Maria José de Britto Costa; Milan, Eveline Pı́polo; Melo, Maria Celeste Nunes de

doi:10.1590/s1517-83822010000200009

Cited by 13 publications

(7 citation statements)

References 24 publications

(32 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Phenotypic MRSA identification was confirmed by the disk diffusion method using a cefoxitin disk; all of the isolates were resistant to cefoxitin (100%). The usefulness of the cefoxitin disk in predicting methicillin resistance has been reported, with sensitivity values reaching 100% [ 26 , 27 ]. However, identification of the mecA gene is the most reliable method of detecting MRSA isolates [ 28 ].…”

Section: Discussionmentioning

confidence: 99%

The Link between Occurrence of Class I Integron and Acquired Aminoglycoside Resistance in Clinical MRSA Isolates

et al. 2021

View full text Add to dashboard Cite

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial infections because of its high resistance. Here, we study the antibiotic resistance in MRSA clinical isolates and their relation to integron I occurrence. A total of 88 clinical Staphylococcusaureus isolates were collected. MRSA were identified by the disk diffusion method (DDM) and confirmed by PCR, and antibiogram was determined by DDM. Integron I, II and the aacA4 gene were investigated by PCR. Integrase-positive strains were analyzed for the presence of resistance gene cassettes by sequencing. All isolates were identified as MRSA by DDM and confirmed by PCR. All isolates were resistant to ampicillin and cefoxitin. Concerning aminoglycosides, the frequency of resistance was reported for streptomycin (60.7%), tobramycin (37.1%) gentamicin (36%), and for amikacin (15.9%). Integron I was detected in 41 isolates (46.6%), while integron II was detected in three isolates (3.4%). Sequencing of the integron I-cassette indicated the exclusive prevalence of addA gene variants mediating aminoglycoside resistance. The aacA4 gene was found in DNA of 31 isolates (35.22%). This study revealed the high existence of MRSA. Furthermore, the AacA4 gene and class I integron harboring aadA gene were predominant in MRSA isolates.

show abstract

Section: Discussionmentioning

confidence: 99%

The Link between Occurrence of Class I Integron and Acquired Aminoglycoside Resistance in Clinical MRSA Isolates

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Cefoxitin is recommended as a phenotypic marker because it predicts mecA gene mediated methicillin resistance 20,32 .…”

Section: Discussionmentioning

confidence: 99%

Prevalence of resistance phenotypes in Staphylococcus aureus and coagulase-negative isolates of venous ulcers of primary healthcare patients

Martins

Santos

Leão

et al. 2012

Rev. Soc. Bras. Med. Trop.

View full text Add to dashboard Cite

Introduction:In venous ulcers, the presence of Staphylococcus aureus and coagulase-negative staphylococcus resistance phenotypes can aggravate and limit the choices for treatment. Methods: Staphylococcus isolated from 69 patients (98 ulcers) between October of 2009 and October of 2010 were tested. The macrolide, lincosamide, streptogramin B (MLS B ) group resistance phenotype detection was performed using the D-test. Isolates resistant to cefoxitin and/or oxacillin (disk-diffusion) were subjected to the confirmatory test to detect minimum inhibitory concentration (MIC), using oxacillin strips (E-test®). Results: The prevalence of S. aureus was 83%, and 15% of coagulase-negative staphylococcus (CoNS). In addition were detected 28% of methicillin-resistant Staphylococcus aureus (MRSA) and 47% of methicillin-resistant coagulase-negative staphylococcus (MRCoNS). Among the S. aureus, 69.6% were resistant to erythromycin, 69.6% to clindamycin, 69.6% to gentamicin, and 100% to ciprofloxacin. Considering the MRSA, 74% were highly resistant to oxacillin, MIC ≥ 256µg/mL, and the MLS B c constitutive resistance predominated in 65.2%. Among the 20 isolates sensitive to clindamycin, 12 presented an inducible MLS B phenotype. Of the MRCoNS, 71.4%were resistant to erythromycin, ciprofloxacin and gentamicin. Considering the isolates positive for β-lactamases, the MIC breakpoint was between 0.5 and 2µg/mL. Conclusions: The results point to a high occurrence of multi-drug resistant bacteria in venous ulcers in primary healthcare patients, thus evidencing the need for preventive measures to avoid outbreaks caused by multi-drug resistant pathogens, and the importance of healthcare professionals being able to identifying colonized versus infected venous ulcers as an essential criteria to implementing systemic antibacterial therapy.

show abstract

“…La presencia de aislados con disparidad entre los resultados fenotípicos y moleculares demuestra que la detección de la resistencia mediante métodos fenotípicos y la amplificación del gen mecA no deben ser utilizados como métodos separados para la detección de la resistencia a la meticilina, ya que pueden haber otros mecanismos de resistencia involucrados. En cuanto a los métodos fenotípicos, es recomendable que para la detección de la resistencia a la meticilina se usen en paralelo los antibióticos cefoxitina y oxacilina, ya que la prueba con oxacilina puede detectar la resistencia a la meticilina mediada por varios mecanismos incluyendo el gen mecA y con la cefoxitina se puede predecir la resistencia a la meticilina mediada por el gen mecA, teniendo en cuenta que actúa como inductor de la expresión de dicho gen [30][31][32][33].…”

Section: Discussionunclassified

“…Los porcentajes de sensibilidad al antibiótico cefoxitina, encontrados en esta investigación, son similares a los de otros autores, quienes reportaron valores hasta del 100% de sensibilidad [26,29,[34][35][36][37][38][39]. Todos ellos concluyeron que la prueba de difusión por disco con cefoxitina es excelente para predecir la presencia de mecA en Staphylococcus aureus, ya que presenta un alto grado de sensibilidad y especificidad en comparación con la reacción en cadena de la polimerasa y es muy preciso para la detección de resistencia a la meticilina.…”

Section: Discussionunclassified

Comparación de métodos fenotípicos y moleculares para la detección de resistencia a meticilina en Staphylococcus aureus

Morales-Parra

García-Cuan

2015

Med. Lab.

View full text Add to dashboard Cite

Introducción: la detección de resistencia a meticilina en aislados de Staphylococcus aureus por el laboratorio es difícil debido a la heterogeneidad en la expresión fenotípica en estas bacterias. Objetivos: comparar métodos fenotípicos y moleculares para la detección de resistencia a meticilina en Staphylococcus aureus. Materiales y métodos: se evaluó la resistencia a la meticilina en 50 aislados de Staphylococcus aureus por los métodos de difusión en agar, microdilución en caldo y dilución en agar. Se utilizó la reacción en cadena de la polimerasa para detectar el gen de resistencia mecA como estándar de referencia. Se determinó para cada método la sensibilidad, especificidad, valores predictivos y eficiencia. Resultados: la resistencia a la meticilina se encontró en el 50% (25/50) de los aislados de Staphylococcus aureus por los métodos de difusión en agar, microdilución en caldo (cefoxitina) y dilución en agar, y en el 52% (26/50) por microdilución en caldo (oxacilina). El 42,0% (21/50) de los aislados presentaron el gen mecA. Del total de aislados, 10 (20%) demostraron un fenotipo discrepante al obtenido molecularmente, siete falsamente resistentes y tres falsamente sensibles. La sensibilidad de los métodos fenotípicos varió entre 85,7% y 90,5%, la especificidad entre 75,9% y 79,3%, el valor predictivo positivo entre 72,0% y 76,0%, el valor predictivo negativo entre 88,5% y 92,0% y la eficiencia entre 80,4% y 84,0%. Conclusiones: los resultados demostraron que los métodos fenotípicos son confiables para la detección de resistencia a la meticilina de Staphylococcus aureus.

show abstract

Evaluation of different methods for detecting methicillin resistance in Staphylococcus aureus isolates in a university hospital located in the Northeast of Brazil

Cited by 13 publications

References 24 publications

The Link between Occurrence of Class I Integron and Acquired Aminoglycoside Resistance in Clinical MRSA Isolates

The Link between Occurrence of Class I Integron and Acquired Aminoglycoside Resistance in Clinical MRSA Isolates

Prevalence of resistance phenotypes in Staphylococcus aureus and coagulase-negative isolates of venous ulcers of primary healthcare patients

Comparación de métodos fenotípicos y moleculares para la detección de resistencia a meticilina en Staphylococcus aureus

Contact Info

Product

Resources

About