Molecular Identification of Prevalent Streptococcus Pyogenes Serogroup Associated with Respiratory Tract Infections in Children

Abstract

The current study intends to characterize the respiratory tract infections that have an association with gram positive bacterial pathogens, emm typing, the pattern of antibacterial resistance in isolated pathogens, phenotyping of virulence factor and molecular detection of Macrolide resistance gene. Various samples from patients with respiratory tract infections were collected and identification and antimicrobial susceptibility of clinical isolates was performed as per standard laboratory procedure.  Macrolides (Eruthromycin, Clindamycin)-resistant isolates were again subjected to MIC method. Macrolide-inducible resistance to clindamycin (D test) was conducted upon Erythromycin and Clindamycin discs. Multiplex PCR was used to detect the resistance genes in all the three types of macrolide resistance strains. Serum Opacity Factor (SOF) was detected for all the isolates of GAS. Every isolate was checked to produce biofilm through micro titre plate method. Bacterial growth got registered in 156 (36.28%) samples. The most common isolate from URI samples was GAS i.e., 64 (14.9%), only to be followed by GGS 38(8.8%), GCS 29 (6.7%) and Staphylococcus aureus 18 (4.2%). Among GAS, only one isolate was recorded from blood, whereas 8.50% from sputum and the rest. All 71 GAS isolates were found to exhibit sensitivity towards Penicillin and Ceftriazone. GAS exhibited 55% Mtype of resistance whereas 40% were resistant to cMLS and 5% to iMLS. GCS showcased an equal number of cMLS and M type too. GGS portrayed 54.54% resistance to cMLS followed by 36.36% to Mtype and 9.09% to iMLS. The current study found iMLS type with least resistance. The current study identified that Streptococcus pyogenes is the most common bacteria that cause and recur the infection. The prevalence of resistance tends to change geographically and periodically. For this purpose and to achieve a sound public health outcome, periodical screening of antibiotic-resistance pattern becomes inevitable.