New drug in pipeline may help fight multidrug resistant-Staphylococcus aureus

51st ICAAC

Issue: October 2011

CHICAGO — New study results indicate that ceftaroline was consistently active against Staphylococcus aureus in patients of all ages, according to findings presented here at the 51st Interscience Conference on Antimicrobial Agents and Chemotherapy.

The study compared S. aureus characteristics from adult and pediatric patients from the 2009 AWARE Surveillance Program.Kevin Krause, BA, senior scientist at Cerexa Inc., Oakland, Calif., presented the findings and said that ceftaroline, the active form of CPT fosamil (Teflaro, Forest), was consistently active in vitro independent of patient age groups.

“Although this drug is not yet approved for use in children, the basic finding of this study is that there is no difference in resistance isolates between the pediatric and adult age groups,” Krause told Infectious Diseases in Children. He added that there are consistent minimum inhibitory concentrations (MIC₉₀) across all age groups with ceftaroline.

The researchers collected 2,311 consecutive S. aureus isolates from 52 sites representing the nine US census regions. Isolates were stratified for analysis by patient age in years: aged 2 years or younger (n=195); aged 3 to 5 years (n=52); aged 6 to 14 years (n=122); aged 15-17 years (n=47); aged 18-64 years (n=1,232); and aged 65 and older (n=663).

Data on nosocomial or community-acquired status was available for 1,511 of the studied isolates. Within this subset, children aged 0 to 2 years (19%) and patients aged older than 18 years (19.3%) were nearly three times more likely to have a nosocomial S. aureus compared with children and adolescents aged 3 to 17 years (7.2%).

Isolates from children aged 0 to 2 years and adults were 50.4% resistant to two or more classes of drugs. Isolates from patients aged 3 to 17 years were 38.5% multidrug-resistant. Methicillin-resistant S. aureus (MRSA) rates varied little across age groups, ranging from 42.3% in the 3- to 5-year-old age group to 53.3% in the 15- to 17-year-old age group.

The researchers noted a correlation between patient age and levofloxacin, with the highest resistance seen in adults aged 65 years and older (62%) and patients aged 18 to 64 years (58%). Children aged 15 years to 17 years had the third highest levofloxacin (Levaquin, Janssen) resistance rate (30%), followed by 27% for children aged 6 to 14 years. The rates dropped to 19% for children aged 5 years and younger.

Five linezolid-resistant S. aureus isolates (MIC > 8 mcg/mL) were recovered from five patients ranging in age from 14 to 68 years. In contrast, ceftaroline retained consistent activity against isolates with varying resistance phenotypes. Infection source and patient age also had no effect on ceftaroline MIC, according to Krause and colleagues.

Ceftaroline is a broad-spectrum cephalosporin active against MRSA. CPT fosamil was approved for use in 2009 for treatment of adult patients with acute bacterial skin and skin structure infections and community-acquired bacterial pneumonia and is currently under review in Europe.

MICs were determined using Clinical and Laboratory Standards Institute methods. — by Cassandra A. Richards

Disclosures: Mr. Krause reports working for Cerexa.

For more information:

Krause K. #G3-179. Profile of Staphylococcus aureus Isolated from United States (USA) Pediatric Patients During the 2009 Ceftaroline AWARE Surveillance Program. Presented at: 51st ICAAC. Sept. 17-20, 2011. Chicago.

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