Background: Infections caused by MDROs are associated with significant morbidity and mortality. Early detection of these organisms causing colonization or infection may help prevent their transmission and improve patient outcomes.
Methods: A molecular diagnostic panel using TaqMan assays was designed to screen for twenty-six multidrug-resistance genes that impact four major classes of antibiotics: aminoglycosides, β-lactams, fluoroquinolones, and macrolides. In addition, a multiplex molecular panel (TEM-PCR^TM) was used to identify commonly encountered respiratory pathogens and four resistance genes associated with MRSA. Patient demographics, discharge diagnosis, and sputum culture results were also obtained.
Results: We enrolled 302 patients with mean age of 55yrs and 52% females. The most common discharge diagnoses were pneumonia 31%, URI 11%, sepsis 10%, COPD and HCAP 8%. Among 302 patients, the following resistance genes were detected: qnrS (1), SHV (7), TEM (143), OXA-1 (2), ACT/MIR (7), CTX-M (3), blaCMY (1), ermC (206), ermA (55), ermB (132), and mecA (53). Females had higher or similar rates of detection of all resistance genes except for Staphylococcus aureus, males had a higher rate of detection of the mecA gene (19 vs 14%). One of the S. aureus pathogenicity genes (PVL) was noted in 12 patients. Those patients with HCAP had high detection rates of TEM (34%), ermB (41%) and ermC (54%) while COPD patients had higher detection rates for ACT/MIR (4%). Pneumonia patients had high detection rates of TEM, ermB and ermC. Sputum cultures were positive in 17% of 119 specimens; the most common organisms were Pseudomonas and MRSA. In contrast, TEM-PCR was positive in 55% of 302 specimens; MRSA, Pneumococcus and Haemophilus influenza were the most common organisms, which matched culture results. At least one MDRG was detected in 76% of patients with negative sputum cultures. Of the 53 positive MRSA patients detected via TEM-PCR, 92% had at least one MDRG detected via TaqMan assay but in only 80% of MRSA negative patients.
Conclusion: MDRGs were detected in our hospitalized patients from the respiratory tract. Further studies are needed to assess the benefit of molecular testing of MDRG for screening and management of patients at high risk of MDROs infection.
A. Gaba, None
M. Thompson, None
J. Edwards, None
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