Adjunctive Clindamycin in Invasive Group A/B Beta-Hemolytic Streptococcus

The researchers wanted to gather evidence about the efficacy of adding clindamycin to β-lactam antibiotics to treat patients with severe iGAS and those with iNABS infections.

Patients with invasive group A b-hemolytic streptococcal (iGAS) infections benefited from adjunctive clindamycin therapy, but not patients with invasive non-group A/B b-hemolytic streptococcal (iNABS) infections. These findings, from a retrospective, multicenter cohort study, were published in Lancet Infectious Diseases.

The Cerner Health Facts database, which contains clinical medical records from 233 hospitals in the United States, was used for this analysis. Records (N=1956) from inpatients admitted to 118 hospitals between 2000 and 2015 with any clinical cultures positive for b-hemolytic streptococci infection were included. Propensity matching in a 1:2 ratio was performed for patients who did or did not receive adjunctive clindamycin.

Of the patients who were positive for iGAS (n=1079) or iNABS (n=877), some patients received clindamycin (n=343; n=116, respectively) and some did not (n=736; n=761, respectively).

Among patients with iGAS, clindamycin recipients were significantly younger (P =.0008), less likely to be White (P =.016), more likely to receive penicillin and vasopressors (P <.0001 for both), had more instances of necrotizing fasciitis (P <.0001), and had more admittances to the intensive care unit (P =.0001).

Among patients with iNABS, clindamycin recipients were significantly younger (P =.023), had more instances of necrotizing fasciitis (P =.0006), and more likely to be female (P =.014), to be obese (P =.045), or to receive ampicillin (P =.0004).

To remove baseline discrepancies, propensity matching was performed, including 277 clindamycin-treated and 500 untreated patients with iGAS and 102 clindamycin-treated and 193 untreated patients with iNABS. Patients with iGAS receiving clindamycin had lower in-hospital mortality (adjusted odds ratio [aOR], 0.44; 95% CI, 0.23-0.81; P =.011).

Among patients without vasopressor-dependent shock or necrotizing fasciitis, clindamycin was associated with decreased mortality (OR, 0.48; 95% CI, 0.21-1.16; P =.11). Decreased mortality was associated with receiving more than 1 day of clindamycin treatment (OR, 0.45; 95% CI, 0.23-0.87; P =.016) or more than 2 days of clindamycin treatment (OR, 0.47; 95% CI, 0.23-0.94; P =.032).

Patients with iGAS receiving clindamycin had hospitalization durations of 7 (interquartile range [IQR], 5-11) days, which was longer than those not treated with clindamycin (6; IQR, 4-8 days; P <.0001).

In-hospital mortality was higher among patients with iNABS receiving clindamycin (aOR, 2.60; 95% CI, 0.94-7.52; P =.067).

This study was limited by not including data on clindamycin resistance.

The conclusions drawn from these data were that adjunct clindamycin in addition to b-lactam antibiotics significantly decreased mortality among patients with iGAS, regardless of vasopressor-dependent shock or necrotizing fasciitis status.


Babiker A, Li X, Lai YL, et al. Effectiveness of adjunctive clindamycin in β-lactam antibiotic-treated patients with invasive β-haemolytic streptococcal infections in US hospitals: a retrospective multicentre cohort study. Published online December 14, 2020. Lancet Infect Dis. doi:10.1016/S1473-3099(20)30523-5.