History of Medicine


An Open Access Journal

Molecular profile of Streptococcus pneumoniae from Nasopharyngeal swabs of patients with pneumonia using RAPD and PCR detection of lytA, PsaA2, and HtrA virulence genes

Jaafar Gh. Alomairi
Faculty of Nursing, Medical Basic Science Department, University of Thi-Qar, Iraq
Baidaa Rasoul Dakhil
Thi-Qar Education Directorate, Thi-Qar, Iraq
Abdulaziz Salih Abdulaziz
Faculty of Vet. Medicine, Microbiology Department, University of Thi-Qar, Iraq


The present work does underline the molecular profiling of ten Streptococcus pneumoniae clinical strains isolated from nasopharyngeal swabs of patients suffering from pneumonia by the aid of RAPD technique and molecular detection of three virulence genes namely lytA, PsaA2, and HtrA. Nasopharyngeal swabs taken from patients with pneumonia, consulted a pulmonologist at Nasiriya Hospital in Iraq, were streaked on blood agar plates. Ten clinical strains showed typical Streptococcus pneumoniae colonial morphology:  Gram-positive diplococcic, small, grey, moist, and mucoid with typical green zone of α-hemolysis on blood agar plates. All tested clinical strains were sensitive to optochin on Müller Hinton agar plates. Confirmatory tests with VITEK2 system, bile solubility, and catalase test did verify the affiliation of the ten tested clinical strains as Streptococcus pneumoniae. The frequency of occurrence of lytA, PsaA2, and HtrA genes was 100% (n= 10 /10), 100% (n= 10/10), and 100% (n= 10 /10), respectively among the ten S. pneumoniae clinical strains. The RAPD-640 PCR did succeed to categorize the ten S. pneumoniae clinical strains under study into 9 groups strains (9 clades) according to the resultant DNA banding profile for each strain.  The present data would greatly suggest that the S. pneumoniae is the most prevailing pathogen among patients with pneumonia within the taken sample size.

Keywords: Streptococcus pneumoniae; Nasopharyngeal swabs; of patients with pneumonia; RAPD technique; PCR detection of lytA, PsaA2, and HtrA. ,


From 2021

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