Abstract

OBJECTIVE:

To determine the microbiology, particularly the prevalence of MRSA, in pediatric patients with community-acquired bacterial lymphadenitis. Long considered a nosocomial organism, methicillin-resistant Staphylococcus aureus (MRSA) has recently emerged as a cause of community-acquired infections. Resistance to other classes of antibiotics, including clindamycin, is prevalent amongst S. aureus, as well.

METHODS:

A retrospective review of the medical records and culture results of patients under the age of 18 who underwent trans-cervical surgical drainage of abscessed lymph nodes between the years 2000 and 2006.

RESULTS:

Sixty-two patients were identified for whom microbiology data were available. Six infections were classified as parapharyngeal on imaging; the remainder involved cervical chain lymph nodes. Forty-nine patients grew microorganisms on culture while 13 collections had no growth. The most common organism was S. aureus (63% of positive cultures); followed by beta-hemolytic group A Streptococcus (22%). Of S. aureus isolates, 27% were oxacillin-resistant (MRSA). All MRSA isolates were sensitive to clindamycin and trimethoprim/sulfamethoxazole; 63% were sensitive to ciprofloxacin, and 25% sensitive to erythromycin. Of methicillin-sensitive S. aureus isolates, 100, 86, and 82% were sensitive to trimethoprim/sulfamethoxazole, clindamycin, and ciprofloxacin, respectively. All MRSA isolates were identified during the latter half of the study period (2003-2006); none grew prior to 2003.

CONCLUSIONS:

MRSA is a common pathogen in community-acquired lymphadenitis, and its incidence is rising. Resistance to clindamycin, a drug commonly used to treat MRSA, is prevalent amongst methicillin-sensitive S. aureus. This has important implications regarding the empiric treatment of lymphadenitis in children.