Related Experiment Videos

Fluoroquinolone resistance among Streptococcus pneumoniae in Hong Kong linked to the Spanish 23F clone

P L Ho1, W C Yam, T K Cheung

  • 1University of Hong Kong Special Administrative Region, China. plho@hkucc.hku.hk

Emerging Infectious Diseases
|December 19, 2001
PubMed

Insights

Streptococcus pneumoniae serotypes 6A/B, 19F, and 23F are common in Hong Kong. Ciprofloxacin-resistant strains share genetic similarities, suggesting capsular switching in these Streptococcus pneumoniae isolates.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Genetics

Background:

  • Streptococcus pneumoniae is a leading cause of bacterial infections.
  • Antibiotic resistance in S. pneumoniae is a growing public health concern.
  • Understanding serotype distribution and genetic relatedness is crucial for vaccine development and treatment strategies.

Purpose of the Study:

  • To investigate the serotype prevalence of mucosal Streptococcus pneumoniae isolates in Hong Kong.
  • To analyze the genetic relatedness of ciprofloxacin-resistant and susceptible S. pneumoniae strains.
  • To explore the phenomenon of capsular switching in these isolates.

Main Methods:

  • Collection and serotyping of 140 mucosal Streptococcus pneumoniae isolates.
  • Pulsed-field gel electrophoresis (PFGE) for genetic profiling.
  • Comparison of genetic patterns between antibiotic-resistant and susceptible isolates.

Main Results:

  • Serotypes 6A/B, 19F, and 23F comprised 73% of the isolates.
  • A distinct group of related PFGE patterns was observed in both ciprofloxacin-resistant (14/15) and susceptible (12/16) isolates.
  • These prevalent strains showed evidence of capsular switching and genetic similarity to the Spanish 23F clone.

Conclusions:

  • Serotypes 6A/B, 19F, and 23F are dominant in Hong Kong mucosal S. pneumoniae isolates.
  • A genetically related clone, potentially undergoing capsular switching, is prevalent among both ciprofloxacin-resistant and susceptible strains.
  • The findings highlight the importance of monitoring Streptococcus pneumoniae epidemiology and antibiotic resistance.

Related Concept Videos

Mechanism of Antibiotic Resistance in MRSA01:25

Mechanism of Antibiotic Resistance in MRSA

Antibiotic resistance in bacteria arises when microorganisms evolve the ability to withstand drugs designed to kill them or inhibit their growth, rendering once-effective treatments useless. This phenomenon, driven by genetic change and selection under antibiotic exposure, poses a profound threat to modern medicine. Mechanisms include drug-inactivating enzymes (e.g., β-lactamases), efflux pumps that eject antibiotics, mutations altering antibiotic targets, decreased drug uptake, and acquisition...
Inhibitors of Bacterial DNA Synthesis01:28

Inhibitors of Bacterial DNA Synthesis

Bacterial pathogens depend on precise and efficient DNA replication to sustain infection. Two type II topoisomerases—DNA gyrase and topoisomerase IV—are critical to this process, as they resolve DNA supercoiling and unlink chromosomes during replication. Fluoroquinolones, synthetic derivatives of quinolones, exploit this mechanism by stabilizing the transient DNA–enzyme cleavage complex, preventing strand religation, and causing lethal double-strand breaks. These antibiotics are selectively...
Clinical Significance of Antibiotic Resistance01:25

Clinical Significance of Antibiotic Resistance

Methicillin-resistant Staphylococcus aureus (MRSA) presents a critical public health threat, arising from its capacity to resist β-lactam antibiotics due to acquisition of the mecA gene within the staphylococcal cassette chromosome mec (SCCmec). This gene encodes penicillin-binding protein 2a (PBP2a), which impairs binding efficacy of methicillin and other β-lactams. MRSA has evolved into distinct clonal lineages impacting humans and animals alike, reinforcing its significance within the One...
Development of Antibiotic Resistance01:30

Development of Antibiotic Resistance

Antibiotic resistance is a major public health concern that arises when bacteria evolve mechanisms to withstand the effects of antibiotic treatments. This resistance can be intrinsic, acquired through genetic mutations, or transferred between bacteria via horizontal gene transfer. The development of antibiotic resistance poses significant challenges in treating bacterial infections and necessitates ongoing research to develop new therapeutic strategies.Intrinsic resistance occurs when bacterial...
Gene Regulation in Microbial Communities: Quorum Sensing01:28

Gene Regulation in Microbial Communities: Quorum Sensing

Quorum sensing is a mechanism of bacterial communication that enables coordinated gene expression in response to changes in population density. This facilitates collective behaviors that enhance survival, resource acquisition, and ecological adaptation. This process relies on small signaling molecules called autoinducers that accumulate as bacterial populations grow. When a critical threshold concentration of autoinducers is reached, bacterial cells collectively modify gene expression,...