Infection by Staphylococcus aureus in healthy carrier children residing in Pachuca, Hidalgo State, Mexico

  • Marco Antonio Becerril-Flores Universidad Autónoma del Estado de Hidalgo
  • César Arturo Gómez Durán
  • José Anselmo Hernández Ibarra
  • Erika Janet Varela-Prado
  • Areli Cruz Castañeda
  • Andrés Salas Casas
  • Juan Pablo Núñez-Martínez


Infections by Staphylococcus aureus are a great worldwide public health problem due to easiness of transmission, via inhalation or direct contact in hospitals. Among infected individuals there are asymptomatic carriers that cause propagation and transmission of these infections within the hospital population. In Mexico, studies about prevalence of infections in healthy carriers by this bacterium are scarce. We investigated the prevalence of pharyngeal infections by S. aureus in asymptomatic children (3 to 8 years old) resident in Pachuca, Hidalgo. There were previous old clinic inspections as part of the study wherein 138 healthy children were studied. Samples of exudates from children were obtained and seeded in selective and differential media and they were morphologically identified as S. aureus by Gram staining. Antibiotics resistance was determined for each sample of bacteria. Prevalence of S. aureus infection was 20.29%, 12.69% in girls, and 26.66% in boys. Pre-school children showed a higher rate of infection than those in elementary school but there was not a significant difference between them (Χ2=0.92, p>0.05). More than 40% of S. aureus strains were ß-hemolytic, and half of the bacteria isolated from children in preschool is resistant to any of the antibiotics studied and resistant to at least one of the antibiotics assayed. The greatest resistance was to ciprofloxacin and erythromycin. Finding children infected with S. aureus as healthy carriers may be, in fact an epidemiologic risk for the entire population. Furthermore, since there are resistant strains of this microorganism, physicians must be very sensible of resistant patterns when selecting antibiotics.