Prevalence, severity, and treatment of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) skin and soft tissue infections in 10 medical clinics in Texas: a South Texas Ambulatory Research Network (STARNet) study

Abstract

Objectives: Quantify the prevalence, measure the severity, and describe treatment patterns in patients who present to medical clinics in Texas with community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) skin and soft-tissue infections (SSTI).

Methods: Ten primary care clinics participated in this prospective, community-based study. Clinicians consented patients and collected clinical information, pictures, and wound swabs; data were processed centrally. MRSASelect™ was used for identification. Susceptibilities were determined via Etest®.

Results: Overall, 73 of 119 (61%) patients presenting with SSTIs meeting eligibility requirements had CA-MRSA. Among these, 49% were male, 79% were Hispanic, and 30% had diabetes. Half (56%) of the lesions were ≥ 5 cm in diameter. Most patients had abscesses (82%) and many reported pain scores of ≥ 7 of 10 (67%). Many presented with erythema (85%) or drainage (56%). Most received incision and drainage plus an antibiotic (64%). Antibiotic monotherapy was frequently prescribed: trimethoprim-sulfamethoxazole (TMP-SMX) (78%), clindamycin (4%), doxycycline (2%), and mupirocin (2%). The rest received TMP-SMX in combination with other antibiotics. TMP-SMX was frequently administered as one double-strength tablet twice daily. Isolates were 93% susceptible to clindamycin and 100% susceptible to TMP-SMX, doxycycline, vancomycin, and linezolid.

Conclusions: We report a predominance of CA-MRSA SSTIs, favorable antibiotic susceptibilities, and frequent use of TMP-SMX in primary care clinics.

Figure 1

Wound Characteristics for Patients with CA-MRSA SSTIs, n=73

Figure 2

Infected Body Sites for Patients with CA-MRSA SSTIs, n=73

Figure 3. Infection Severity for Patients with CA-MRSA SSTIs, n=70*

* Moderate or complicated infections were defined by the presence of either a lesion ≥ 5 cm or a patient history of diabetes. Lesion size was missing for 3 patients.

Figure 4. Treatment Approach for Patients with CA-MRSA SSTIs, n=72*

* Treatment approach was unavailable for 1 patient

Figure 5. Antibiotics Prescribed for Patients with CA-MRSA SSTIs, n=64*

*Antibiotics were not available for 9 patients †Combination therapy = TMP-SMX + beta-lactam (4/9), TMP-SMX + clindamycin (2/9), TMP-SMX + doxycycline (2/9), clindamycin + mupirocin (1/9)