FRIDAY, July 8 (HealthDay News) -- Cases of pneumonia in children caused by Staphylococcus aureus bacteria doubled over the last decade at a Texas hospital, and most of those infections were caused by a particularly aggressive, antibiotic-resistant strain, researchers say.

The investigators looked at the records of 117 children, median age less than one year, who were hospitalized with staph pneumonia at Texas Children's Hospital between 2001 and 2009. Nearly 60 percent of the children had to be treated in the intensive care unit and 30 percent required mechanical ventilation.

Three-quarters of the cases were caused by methicillin-resistant S. aureus(MRSA) while the other 25 percent of cases were caused by antibiotic-susceptible S. aureus. Of the children with MRSA, 90 percent had an aggressive strain called USA300 and were more likely to have complicated pneumonia requiring video-assisted surgery for diagnosis and treatment.

Some of the children with staph pneumonia were also infected with viruses, most often influenza virus. These patients tended to have more severe pneumonia, with higher rates of ICU care and respiratory failure, according to the report published in the July issue of The Pediatric Infectious Disease Journal.

On average, the children in the study required three weeks of treatment with antibiotics. One child died, the study authors noted in a news release from the journal's publisher.

The study offers an update on the "clinical characteristics, admission trends, and molecular epidemiology" of S. aureus pneumonia, lead author Dr. Maria A. Carrillo-Marquez of Texas Children's Hospital in Houston, and colleagues stated in the news release.

The authors called for further studies to identify the best treatment methods for children with S. aureus pneumonia, particularly in cases involving antibiotic-resistant or aggressive strains.

More information

The Nemours Foundation has more about children and pneumonia.