3.2 Co-infection in COVID-19 patients
Among all the 55 COVID-19 patients, 42 cases (42/55, 76.4%) had RT-PCR positive detection against at least one of other respiratory pathogens, including bacterial co-infection (35/55, 63.6%) and viral co-infection (13/55, 23.6%). As shown in Figure 1 , four types of bacteria and five types of viruses were detected in COVID-19 patients. Among co-infected cases, 83.3% (35/42) were detected with bacterial pathogens, which was as follows: SP (25/42, 59.5%), HI (16/42, 38.1%), MC (6/42, 14.3%), and PA (4/42, 9.5%). Moreover, 31.0% (13/42) of co-infected patients were detected with viral pathogens, which included IFV-B (8/42, 19.0%), HRV (3/42, 7.1%), IFV-A (1/42, 2.4%), RSV (1/42, 2.4%) and PIV3 (1/42, 2.4%). In addition, 64.3% (27/42) of co-infected cases were detected with a single pathogen, followed by 35.7% (15/42) with more than one pathogen. The common combination of co-infection (more than one pathogen) were SP+HI+MC (3/42, 7.1%), SP+HI (2/42, 4.8%), SP+HI+PA (2/42, 4.8%) and SP+MC (2/42, 4.8%). More information regarding the distribution of co-infection of other respiratory pathogens in COVID-19 patients was showed in Figure 1 .