Detection of macrolide resistant genes of streptococcus pneumoniae isolated from patients in Hospital USM and its clinical outcomes

• Main Author: Mahmud, Wan Norliyana Wan
• Format: Thesis
• Language: English
• Published: 2017
• Subjects: R Medicine
• Online Access: http://eprints.usm.my/45689/1/Dr.%20Wan%20Norliyana%20Wan%20Mahmud-24%20pages.pdf; http://eprints.usm.my/45689/

Streptococcus pneumoniae is one of the leading pathogen causing pneumonia, meningitis, bacteremia and bacterial otitis media worldwide. It cause more serious disease in young patients less than 5 years old, elderly aged more than 65 years and in patients with underlying medical condition such as malignancy, chronic obstructive airway disease, chronic liver disease, chronic renal disease, diabetes mellitus and smokers. Global increase in antibiotic resistance in S.pneumoniae remains a serious concern worldwide. In global multi-country study of antimicrobial susceptibility in S. pneumoniae, revealed that regional rates of antibiotic resistance were consistently the highest in Asia. The dramatic increase in in-vitro resistance of S.pneumoniae, particularly beta-lactams and macrolide antibiotic raised the questions on clinical impact of antimicrobial resistance on clinical outcomes. The aim of this study is to describe the clinical characteristics and outcome of S. pneumoniae infection, antibiotic susceptibility pattern, distribution of macrolide-resistance determinants and its relationship with macrolides susceptibility pattern and clinical outcomes among patients in Hospital Universiti Sains Malaysia, Kelantan. Methodology This is a descriptive cross sectional study conducted in Hospital Universiti Sains Malaysia. S.pneumoniae, in which non-duplicate isolates were collected from various clinical specimens from June 2014 to December 2015. Susceptibility to six antibiotics i.e penicillin, erythromycin, azithromycin, vancomycin, trimetophrim-sulfamethoxazole and amoxycillin-clavulanic acid were determined using E-test strips (BioMerieux SA, France). The results were interpreted according to CLSI guidelines. All isolates were subjected to polymerase chain reaction (PCR) analysis to detect macrolide-resistance determinants. Patients' clinical data including demographic, clinical diagnosis, risk factors, and outcomes were obtained from clinical notes. Results A total of 113 patients with positive growth of S. pneumoniae from clinical samples were included in the study. Community-acquired pneumonia is the predominant presentation of pneumococcal infection. Penicillin resistance rate was 7.1%, with MIC ranging between 0.012 – >32 μg/ml and MIC90 of 1μg/ml. Approximately 26.5% of the isolates resistant to erythromycin with MIC range of 0.03 – >256 1μg/ml and MIC90 of 32 μg/ml. Among the erythromycin-resistant isolates, majority were found to have mef(A) gene (50.4%), erm(B) gene (20%), 16.7% with combination of mef(A) and erm(B) and 13.3% with none of the two genes. There were no significant association between presence of macrolide resistance determinants with mortality (p = 0.837) or complications (p > 0.999 for empyema and cardiac complication; p = 0.135 for subdural abscess)Conclusion Overall, the isolates showed good susceptibility towards all antibiotics tested except for azithromycin. The outcome and complications of pneumococcal diseases were not significantly different between macrolide-resistance than those with macrolide-susceptible groups and were not affected by the presence of macrolide resistance determinants in the pneumococcal isolates.