Microbiology
Farzad Mohammadi Ebli; Zoheir Heshmatipour; Khadijeh Daneshjou; Seyed Davood Siadat
Abstract
Background & Objective: Streptococcus pneumoniae, Haemophilus influenzae and Streptococcus pyogenes are among the most important causes of infection in human. Inventing rapid methods to identify these species can help in providing appropriate and effective treatment options. Therefore, the current ...
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Background & Objective: Streptococcus pneumoniae, Haemophilus influenzae and Streptococcus pyogenes are among the most important causes of infection in human. Inventing rapid methods to identify these species can help in providing appropriate and effective treatment options. Therefore, the current study aimed to develop a multiplex touch-down PCR method to identify rapidly the aforementioned species patients' sputum samples, simultaneously.Methods: A total of 50 sputum samples of patients with respiratory infections resistant to treatment were collected. After DNA extraction and primer design, the complete capsule (CAP) region II, capsular polysaccharide biosynthesis (cpsA) and the structural regulator of transcription (spy) genes were amplified for detecting H. influenzae, S. pneumoniae and S. pyogenes by multiplex touch-down PCR.Results: Among 50 samples prepared from patients with different diseases, 27 samples were positive for amplified genes. The frequency of presence of pathogens in the collected samples included 14% H. influenzae, 20% S. pneumoniae and 20% S. pyogenes. Also, in some patients, the simultaneous presence of two or three pathogens were observed.Conclusion: In general, it can be concluded that the PCR touchdown method developed in the present study is an effective and fast method for the simultaneous identification of H. influenzae, S. pneumoniae and S. pyogenes pathogens in clinical samples of patients.
Microbiology
Zoheir Heshmatipour; Nasibeh Arabameri; Shima Eftekhar Ardebili; Zeinab Jafari Bidhendi
Abstract
Background & Objective: Pseudomonas aeruginosa is an opportunistic pathogen and one of the most common causes of nosocomial infections. This bacterium's antibiotic resistance to the common fluoroquinolone antibiotics, especially ciprofloxacin, is due to mutations in the gyrA and parC genes. This ...
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Background & Objective: Pseudomonas aeruginosa is an opportunistic pathogen and one of the most common causes of nosocomial infections. This bacterium's antibiotic resistance to the common fluoroquinolone antibiotics, especially ciprofloxacin, is due to mutations in the gyrA and parC genes. This study aimed to investigate the effect of the mutation in (gyrA, parC) on ciprofloxacin resistance in clinical isolates of Pseudomonas aeruginosa.Methods: A total of 140 clinical samples were collected from hospitals. The samples were identified by standard biochemical tests, and the antibiotic resistance was investigated by the disk diffusion method. DNA was extracted from 30 isolates, and PCR was performed. PCR-sequencing was carried out to assess gyrA and parC mutations in drug-resistant isolates. NCBI-Blast and MEGA7 software was used to analyze the nucleotide sequences.Results: 30 clinical isolates were 80% resistant to ciprofloxacin; meanwhile, in 21 samples, mutations were observed. 87/5% of mutations were related to gyrA (Thr83 → Ile), 79/16 % parC (Ser87 → Leu), and 4/18% (Glu91 → Lys). The antibiotic resistance to ciprofloxacin and mutations in gyrA and parC genes in resistant isolates are significantly related to each other (P<0.05). Conclusion: The mutations in the gyrA and parC genes play an essential role in resistance to ciprofloxacin in clinical isolates of Pseudomonas aeruginosa.
