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Updated: Jul 5, 2026
Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
Published on: May 8, 2013
Current problems in the diagnosis and treatment of hospital-acquired methicillin-resistant Staphylococcus aureus
Masahiro Sakaguchi1, Nobuaki Shime, Naohisa Fujita
1Department of Emergency and Intensive Care Medicine, Otsu Municipal Hospital, Otsu, Japan.
Purpose:
We aimed evaluate clinical problems in the diagnosis and treatment of hospital-associated pneumonia due to methicillin-resistant Staphylococcus aureus (MRSA-HAP) at a single institute.
Methods:
Forty-two patients, diagnosed with MRSA-HAP by a primary physician, who had received antimicrobial therapy during a period of 18 consecutive months at University Hospital, Kyoto Prefectural University of Medicine, were enrolled in the study. For comparison, 36 patients in whom MRSA was recovered from the respiratory tract during the same period, but who were not treated for pneumonia, were chosen as untreated controls. A clinical pulmonary infection score (CPIS) was calculated retrospectively by a chart review. The CPIS was calculated on day 1 and day 3. In the treated group, serum concentrations of each therapeutic drug used were also evaluated.
Results:
The day-1 and day-3 CPIS showed a similar trend in the two at groups, at 2.5 +/- 1.8 and 3.9 +/-1.9, respectively, in the treated group and 2.9 +/- 1.9 and 3.8 +/- 1.6 in the control group. Only two (5%) patients in the treated group showed a CPIS of more than 6 on day 1. Only five patients (12%) in the treated group were treated with antimicrobials at appropriate target therapeutic serum concentrations. The 30-day mortality in the treated group was significantly higher than that in the control group, even when we matched the baseline morbidity of patients using the Acute Physiology and Chronic Health Evaluation II (APACHE II) score.
Conclusion:
This study revealed the clinical problems in our setting, in that MRSA colonization in the respiratory tract was frequently treated as pneumonia, and antimicrobial dosage was frequently insufficient. Prudent differential diagnosis of and treatment for HAP due to MRSA infection should be considered.
Insights
Hospital-associated pneumonia (HAP) due to methicillin-resistant Staphylococcus aureus (MRSA) is often misdiagnosed and undertreated. Insufficient antimicrobial dosing and inappropriate treatment of MRSA colonization as pneumonia led to higher mortality rates in treated patients.
Area of Science:
- Infectious Diseases
- Clinical Medicine
- Pharmacology
Background:
- Hospital-associated pneumonia (HAP) poses a significant clinical challenge, particularly when caused by multidrug-resistant organisms like methicillin-resistant Staphylococcus aureus (MRSA).
- Accurate diagnosis and effective treatment are crucial for improving patient outcomes and preventing the spread of resistant infections.
Purpose of the Study:
- To evaluate clinical challenges in the diagnosis and treatment of MRSA-HAP.
- To identify factors contributing to suboptimal patient outcomes in MRSA-HAP cases.
Main Methods:
- Retrospective chart review of 42 patients diagnosed with MRSA-HAP and treated with antimicrobials.
- Comparison with 36 patients with respiratory tract MRSA recovery but no pneumonia treatment.
- Calculation of Clinical Pulmonary Infection Score (CPIS) on days 1 and 3, and assessment of therapeutic drug serum concentrations.
Main Results:
- Similar CPIS trends were observed between treated and untreated groups.
- Only 5% of treated patients had a CPIS > 6 on day 1, and 12% received appropriate antimicrobial serum concentrations.
- The 30-day mortality was significantly higher in the treated MRSA-HAP group compared to controls, even after adjusting for baseline severity (APACHE II score).
Conclusions:
- Respiratory tract MRSA colonization is frequently misdiagnosed as pneumonia, leading to inappropriate antimicrobial use.
- Antimicrobial dosages were often insufficient, contributing to poor outcomes.
- Prudent differential diagnosis and optimized treatment strategies are essential for managing MRSA-HAP.
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