Lactational Breast Abscesses Caused by Methicillin-Resistant or Methicillin-Sensitive Staphylococcus aureus Infection and Therapeutic Effect of Ultrasound-Guided Aspiration.

Background and Objective: We investigated whether (1) there are any differences in lactational breast abscesses between patients from whom methicillin-resistant Staphylococcus aureus (MRSA) and those from whom methicillin-sensitive S. aureus (MSSA) were isolated from pus samples and (2) there are differences in the effects of ultrasound-guided aspiration. Materials and Methods: The clinical data of 171 patients with lactational breast abscesses treated by ultrasound-guided aspiration in Beijing from January to July 2018 were retrospectively analyzed. The patients were divided into MSSA infection ( N  = 132) and MRSA infection ( N  = 39) groups according to their bacterial culture results. Abscess cavity location, abscess cavity number, maximum abscess cavity size, antibiotic utilization rate, and cure rate were compared between the groups. Cure rate refers to the proportion of the total number of cases remaining after the elimination of failed cases. The number of ultrasound-guided aspiration procedures performed for healing between the two groups was also compared. Results: There were no significant differences in abscess cavity location, abscess cavity amount, and abscess cavity size between both groups. The antibiotic utilization rate of the two groups were 58.3% (MSSA, 77/132) and 69.2% (MRSA, 27/39), respectively, and there were no significant differences between both groups. The cure rates of ultrasound-guided aspiration of the two groups were 97.7% (MSSA, 129/132) and 92.3% (MRSA, 36/39), and there were no significant differences between both groups. There were also no significant differences in the median number of aspiration performed for cure between the MRSA infection group (median = 3, range = 1-10) and the MSSA infection group (median = 3, range = 1-14). Conclusion: Lactational breast abscesses are the same irrespective of the type of S. aureus infection. Treatment by ultrasound-guided aspiration for patients with MRSA infection can achieve the same effect as that for those with MSSA infection.