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Published on: February 23, 2014
Hospital-acquired pneumonia caused by multidrug-resistant Streptococcus pneumoniae serotype 15A
Hidemasa Akazawa1, Shinnosuke Fukushima1,2, Kenta Nakamoto1
1Department of Infectious Diseases, Okayama University Hospital, 2-5-1 Shikata-cho, Kitaku, Okayama, 700-8558, Japan.
Background:
Streptococcus pneumoniae remains a common cause of community-acquired pneumonia but is an infrequent pathogen in hospital-acquired pneumonia (HAP). Non-vaccine serotypes of multidrug-resistant (MDR) S. pneumoniae strains have been emerging globally, posing an increased risk of nosocomial infection.
Case:
A 71 year-old man developed pneumonia on postoperative day 4 following spinal fusion surgery. Despite initial treatment with ampicillin/sulbactam, his condition deteriorated, requiring ICU admission and mechanical ventilation. Microbiological testing confirmed S. pneumoniae as a causative pathogen, and ceftriaxone was empirically administered based on the local antibiogram. However, antimicrobial susceptibility testing revealed resistant profiles to penicillin (minimum inhibitory concentration [MIC], 8 µg/mL), ceftriaxone (MIC, 16 µg/mL), meropenem (MIC, 1 µg/mL), macrolides, and clindamycin, while demonstrating susceptibility to levofloxacin and vancomycin. The therapeutic regimen was subsequently adjusted to levofloxacin, resulting in clinical improvement. The isolate was later identified as serotype 15A, sequence type 63 (ST63).
Conclusion:
This case highlights that MDR S. pneumoniae can cause early-onset HAP and may not be covered by standard empiric therapies, emphasizing the need for careful evaluation of treatment response. Continued surveillance of infections caused by vaccine-escape clones like MDR serotype 15A is essential, given their increasing clinical relevance.
Insights
Multidrug-resistant Streptococcus pneumoniae can cause early hospital-acquired pneumonia, often missed by standard treatments. Surveillance of emerging strains like MDR serotype 15A is crucial for effective patient care.
Area of Science:
- Infectious Diseases
- Clinical Microbiology
- Critical Care Medicine
Background:
- Streptococcus pneumoniae is a frequent cause of community-acquired pneumonia but rarely causes hospital-acquired pneumonia (HAP).
- Emerging global strains of multidrug-resistant (MDR) S. pneumoniae, particularly non-vaccine serotypes, increase the risk of nosocomial infections.
- MDR S. pneumoniae poses a significant challenge due to resistance to common antibiotics.
Purpose of the Study:
- To report a case of early-onset HAP caused by a multidrug-resistant Streptococcus pneumoniae serotype 15A.
- To highlight the limitations of standard empiric antibiotic therapies against emerging MDR S. pneumoniae strains.
- To emphasize the importance of antimicrobial susceptibility testing and surveillance of vaccine-escape clones.
Main Methods:
- A case study of a 71-year-old male patient who developed HAP post-spinal fusion surgery.
- Initial treatment with ampicillin/sulbactam, followed by empirical ceftriaxone, with subsequent adjustment to levofloxacin based on susceptibility testing.
- Identification of the causative pathogen as S. pneumoniae serotype 15A, sequence type 63 (ST63), with detailed antimicrobial resistance profiling.
Main Results:
- The patient experienced clinical deterioration requiring ICU admission and mechanical ventilation despite initial antibiotic treatment.
- The S. pneumoniae isolate exhibited resistance to penicillin, ceftriaxone, meropenem, macrolides, and clindamycin.
- Treatment with levofloxacin led to clinical improvement, indicating susceptibility to this agent.
Conclusions:
- MDR S. pneumoniae, including serotype 15A, can cause early-onset HAP and may evade standard empiric treatment regimens.
- Close monitoring of treatment response and prompt antimicrobial susceptibility testing are vital for managing HAP.
- Continuous surveillance of vaccine-escape MDR S. pneumoniae clones is essential due to their growing clinical significance.
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