African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5233

Full Length Research Paper

Bacterial identification and antibiotic susceptibility patterns of Staphyloccocus aureus isolates from patients undergoing tonsillectomy in Malaysian University Hospital

Saad Alasil1, Rahmat Omar1*, Salmah Ismail2, Mohd Yasim Yusof3 and Mahmood Ameen2
  1Department of Otorhinolaryngology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia. 2Department of Molecular Medicine, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia. 3Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
Email: [email protected]

  •  Accepted: 31 October 2011
  •  Published: 23 November 2011

Abstract

 

Diagnosis and treatment of chronic tonsillitis (CT) and recurrent tonsillitis (RT) are common problems seen in any otolaryngology clinic. Antibiotic therapy usually fails to prevent the recurrences of these infections leaving the patient with no choice but surgery (tonsillectomy). This study aims to identify the bacteriology of both tonsillar swabs and biopsies specimens among children and adult patients diagnosed with CT and RT (infected tonsils). In addition to obstructive sleep apnea (OSA) and tonsillar hypertrophy (TH) (non-infected tonsils) all undergoing elective tonsillectomy and to characterize the antibiotic susceptibility patterns of the most common isolate. A total number of 138 surgically removed palatine tonsils were collected from 72 patients. Six types of antibiotics were selected to test the susceptibility of Staphylococcus aureus isolates which are methicillin, gentamicin, erythromycin, co-trimoxazole, clindamycin and fusidic acid. The most common isolate was S. aureus (190 isolatre) followed by Haemophilus influenza(83), Streptococcus Group B (61), Haemophilus parainfluenza (33), Klebsiella pneumoniae (32), Streptococcus Group G (29), Streptococcus Group F (14), Streptococcus Group C (12), Pseudomonas aeruginosae (10) and Streptococcus Group A (9) and Streptococcus Group A (9). The number of S. aurues isolates in infected tonsils (RT and CT) was 145 (76.3%) while in non-infected tonsils (OSA and TH) was 45 (23.6%). Three susceptibility patterns were found among S. aureus isolates in all cases, (89.4%) susceptible to all the selected antibiotics, (10.6%) resistant to fusidic acid only, whereas 0.5% resistant to both methicillin and fusidic acid. There was a 30.5% difference in the type of bacterial isolates between tonsillar swab and biopsies. The high prevalence of S. aureus in patients with both infected and non-infected tonsils suggests that this bacterium might not be the aetiological agent of chronic and recurrent tonsillitis. In addition, the high susceptibility rate of methicilin among S. aurues isolates could be due to the fact that S. aurues represents part of the oropharynx normal flora. The increased rate of resistance 10.6% to fusidic acid among methicillin-susceptible S. aureus (MSSA) isolates makes this antibiotic a less potential drug of choice for patients with chronic and recurrent tonsillitis.

 

Key words: Antibiotic susceptibility, Staphylococcus aureus, tonsillectomyswab and biopsy.