PP3 - An analysis of Streptococcus pneumoniae isolates observed at a paediatric tertiary care hospital in Sri Lanka

Abstract

Introduction

Invasive pneumococcal disease is associated with significant morbidity and mortality, especially among children below 5 years in developing countries. Pneumococcal infections caused by antibiotic-resistant strains complicate treatment.

 Objectives

This analysis describes the sources and antibiotic susceptibility patterns of Streptococcus pneumoniae isolates from diagnostic cultures performed at the Lady Ridgeway Hospital for Children in Colombo (LRH) in 2024.

 Design, setting, and methods

A retrospective descriptive analysis was conducted on all Streptococcus pneumoniae isolates from routine samples received at the LRH microbiology laboratory from January 1, 2024, to December 31, 2024. The age and sex of patients, specimen types, and clinical information were extracted from the request forms. Pneumococci were identified using bile solubility and optochin susceptibility tests. Antibiotic susceptibility (AST) was tested with disc diffusion methods. Isolates from sterile sites were sent to the reference laboratory for determination of the minimum inhibitory concentration (MIC). The data was analyzed using SPSS (version 22.0).

 Results

A total of 136 Streptococcus pneumoniae isolates were identified. Among the patients, 75% (102/136) were under the age of five, and 64.7% (88/136) were boys. The majority, 51.5% (70/136), were respiratory specimens, including 48 sputum, nine nasopharyngeal aspirates, six endotracheal aspirates, three bronchoalveolar lavage, two gastric aspirates, one lung tissue, and one nasal swab. Ear swabs accounted for 44.9% (61/136), and there was one pus sample. Four blood culture isolates were from one meningitis and three pneumonia patients, all of whom were under 5 years old.

AST by disc diffusion test for all the isolates revealed high rates of non-susceptibility to penicillin (88.4%), co-trimoxazole (73.2%), erythromycin (62.3%), and clindamycin (40%). Susceptibility to vancomycin (100%) and chloramphenicol (99%) was excellent. MIC testing of the four blood culture isolates at the reference laboratory showed 100% susceptibility to penicillin, cefotaxime, vancomycin, and levofloxacin.

 Conclusion

Of the pneumococcal infections studied, a greater proportion was among children below 5 years.  Higher rates of non-susceptibility to penicillin, cotrimoxazole, and erythromycin were evident. These findings highlight the importance of preventing pneumococcal disease among children antibiotic resistant strains complicate the treatment.