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Penicillin susceptibility of non-serotypeable Streptococcus pneumoniae from ophthalmic specimens

Fumiko Kojima1, Yoshiko Nakagami, Koichi Takemori

  • 1Infectious Diseases Laboratory, Department of Health Sciences, School of Medicine, Kyushu University, Fukuoka, 812-8582, Japan.

Microbial Drug Resistance (Larchmont, N.Y.)
|September 28, 2006
PubMed

Insights

Nontypeable Streptococcus pneumoniae eye infections show intermediate penicillin resistance. Alterations in penicillin-binding protein genes were observed in resistant strains, suggesting widespread resistance mechanisms.

Area of Science:

  • Microbiology
  • Ophthalmology
  • Genetics

Background:

  • Nontypeable Streptococcus pneumoniae (NT SP) are a common cause of ophthalmic infections.
  • Penicillin resistance in S. pneumoniae is a growing public health concern.
  • Understanding resistance mechanisms in ocular NT SP is crucial for effective treatment.

Purpose of the Study:

  • To determine penicillin susceptibility of NT SP isolated from ocular infections.
  • To investigate the presence of penicillin-binding protein (PBP) gene alterations in these isolates.
  • To correlate PBP gene alterations with penicillin resistance levels.

Main Methods:

  • E-test was used to determine penicillin Minimum Inhibitory Concentrations (MICs) for 25 ophthalmic NT SP isolates.
  • Polymerase Chain Reaction (PCR) was employed to detect alterations in the pbp1a and pbp2b genes.
  • Isolates were categorized as penicillin-sensitive (PSSP), intermediately resistant (PISP), or resistant (PRSP).

Main Results:

  • Out of 25 isolates, 15 were penicillin-sensitive (PSSP) and 10 were intermediately resistant (PISP). No penicillin-resistant strains (PRSP) were detected.
  • PBP gene alterations were found in 20% of PSSP isolates (3/15) and 20% of PISP isolates (2/10).
  • Alterations in pbp1a or pbp2b genes were associated with intermediate penicillin resistance in NT SP.

Conclusions:

  • Penicillin resistance is present among NT SP strains causing ophthalmic infections.
  • PBP gene alterations, particularly in pbp1a and pbp2b, are associated with intermediate penicillin resistance.
  • These findings highlight the need for continued surveillance and understanding of antibiotic resistance in ocular pathogens.

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