Multidrug Resistance and Virulence Profiling of Fomite-Resident Streptococcus species

Nose mask is a fomite and its usage was mandatory during the COVID-19 outbreak. Its effectiveness has been established; however, as a fomite, it can harbor opportunistic respiratory pathogens such as Streptococcus spp., which could complicate COVID-19 infections. This study profiled Streptococcus species resident on nose masks obtained from consenting participants. Phenotypic assays and 16S rRNA sequencing were used to identify Streptococcus spp. resident on the interior and exterior of 100 nose masks analyzed. Antibiotic resistance (AMR) was determined with disc diffusion and broth microdilution assays. AMR and virulence makers were profiled with primer-specific PCR amplification. 23% of the analyzed samples had Streptococcus isolates. The isolates were highly resistant to the antimicrobials, including conventional, last-resort antibiotics, disinfectants and antiseptics. All the isolates are multidrug resistant with 80-100% levels of AMR to the 16 antibiotics tested with a Multiple-Antibiotic Resistance index greater than 0.2, indicative of potential pathogens. The isolates harbored tetB, ermB, pbp2B, pbp2b1 (resistance) and lytA, lytA1, ply1, cbpA, lytA, pavA (virulence) markers, which might constitute a serious public health risk. Overall, the study emphasizes the need to assess mask usage and the risks associated with opportunistic pathogens that are resident on frequently used nose masks in the COVID-19 era.