Comparison of Characteristics of Streptococcus dysgalactiae subsp. equisimilis Isolates Causing Repetitive vs Single Infections

Abstract

No study has described Streptococcus dysgalactiae subsp. equisimilis (SDSE) isolates that cause repetitive infections (recurrence and reinfection). We compared the microbiological characteristics of SDSE causing repetitive infections with those causing single infections. Three patients with invasive infections were identified based on their medical records, and multiple SDSE isolates were collected at intervals over three weeks, using a laboratory repository. Isolates from 12 patients with single-episode infections served as controls. Six isolates were collected from three patients with first and second episodes of infection. All isolates causing either repetitive or single-episode infection were subjected to emm typing, multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), and random amplified polymorphic DNA (RAPD) analyses. Amplification of five virulence genes ( sicG , prtF1 , prtF2 , lmb , and cbp ), biofilm formation (BF), and cell invasion abilities (CIAs) were measured as virulent phenotypes. We observed close genetic similarities in the data obtained by emm typing, MLST, PFGE, and RAPD in four isolates from two patients, suggesting recurrence, whereas two isolates from one patient indicated genetic differences in these data, suggesting re-infection. The presence of the five virulence genes and the BF and CIA measurements appeared not to contribute to repetitive infections, compared with isolates causing single-episode infection. In conclusion, clinicians encountering patients with repetitive infections should be aware of both possibilities: recurrence with closely related strains and reinfection with different strains.

Human Keratinocyte Entry of Noninvasive <i>Streptococcus dysgalactiae</i> Subsp. <i>equisimilis</i> from Humans and Companion Animals: Relatedness with Lancefield Group, Source, Virulence-Associated Genes, and Antimicrobial Resistance Phenotype

“…Although SDSE is highly susceptible to β-lactam-class antimicrobials, several reports have identified high rates of resistance to classes of macrolide, lincosamide, or tetracycline (13). Furthermore, profiling of virulence-associated genes (VAGs) encoding fibronectin-binding protein 1/2 (prtF1/prtF2), laminin-binding protein (lmb), collagen-binding protein (cbp), streptococcal inhibitor of complement-mediated cell lysis (sicG), biofilm regulatory protein (brpA), sortase of pilus island 1 (srtp1), and sortase of pilus island 2 (srtp2) has been documented (12,(14)(15)(16)(17). SDSE is increasingly isolated from horses with respiratory, reproductive, or other diseases.…”

Pathogenicity and drug resistance of animal streptococci responsible for human infections

“…Additionally, this species is characterized by many virulence factors. The presence of a different number of pathogenicity factors has been reported in both subspecies, including protein M, streptolysins O and S, streptokinase, hyaluronidase, C5a peptidase, streptococcal complement inhibitors, pyrogenic toxins, and DNases [125][126][127][128]. This presence increases the potential for S. dysgalactiae infections.…”

“…Baracco [4] also highlighted patients with burns in his study because there is a risk of infection with these streptococci during skin transplants. Fujita et al [126] noted that bacteraemia caused by SDSE can recur. Rantala [139] indicated that the most common clinical symptom of recurrent infection is cellulitis.…”

“…Fujita et al . [126] noted that bacteraemia caused by SDSE can recur. Rantala [139] indicated that the most common clinical symptom of recurrent infection is cellulitis.…”

Genetic relatedness of Streptococcus dysgalactiae isolates causing recurrent bacteraemia

“…Various emm types have been reported in studies of recurrent SDSE bacteraemia [5,6] but no specific emm type has been associated with an increased risk [11]. Evidence for close genetic relatedness between SDSE clones that cause recurrence has previously been reported [6,12,13]. In these studies, pulsefield gel electrophoresis or rep-PCR was used to determine similarity between isolates.…”