Pathogen Identification in Suspected Cases of Pyogenic Spondylodiscitis.
Pyogenic spinal infection continues to represent a worldwide problem. In approximately one-third of patients with pyogenic spondylodiscitis, the infectious agent is never identified. Of the cases that lead to organismal identification, bacteria are more commonly isolated from the spine rather than fungi and parasites. This study applied universal prokaryotic16S rRNAPCR as a rapid diagnostic tool for the detection of bacterial agents in specimens from patients suspected of pyogenic spondylodiscitis. Gram and Ziehl-Neelsen staining were used as a preliminary screening measure for microbiologic evaluation of patient samples. PCR amplification targeting16S rRNAgene was performed on DNA extracted from 57 cases including specimens from epidural abscesses, vertebral, and disc biopsies. Positive samples were directly sequenced. MRI findings demonstrated that disc destruction and inflammation were the major imaging features of suspected pyogenic spondylodiscitis cases, as 44 cases showed such features. The most common site of infection was the lumbar spine (66.7%), followed by thoracic spine (19%), the sacroiliac joint (9.5%), and lumbar-thoracic spine (4.8%) regions. A total of 21 samples amplified the16S rRNA-PCR product. Sanger sequencing of the PCR products identified the following bacteriological agents:Mycobacterium tuberculosis(n= 9; 42.9%),Staphylococcus aureus(n= 6; 28.5%),Mycobacterium abscessus(n= 5; 23.8%), andMycobacterium chelonae(n= 1; 4.8%). 36 samples displayed no visible16S rRNAPCR signal, which suggested that non-bacterial infectious agents (e.g., fungi) or non-infectious processes (e.g., inflammatory, or neoplastic) may be responsible for some of these cases. The L3-L4 site (23.8%) was the most frequent site of infection. Single disc/vertebral infection were observed in 9 patients (42.85%), while 12 patients (57.15%) had 2 infected adjacent vertebrae. Elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) inflammatory markers were noted in majority of the patients. In conclusion, microbiological methods and MRI findings are vital components for the proper diagnosis of pyogenic spondylodiscitis. Our findings suggest that molecular methods such as clinical application of16S rRNAPCR and sequencing may be useful as adjunctive diagnostic tools for pyogenic spondylodiscitis. The rapid turnaround time of16S rRNAPCR and sequencing submission and results can potentially decrease the time to diagnosis and improve the therapeutic management and outcome of these infections. AlthoughS. aureusandM. tuberculosiswere the most common causes of pyogenic spinal infections in this study, other infectious agents and non-infectious etiologies should be considered. Based on study results, we advise that antibiotic therapy should be initiated after a definitive etiological diagnosis.
Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical SciencesAhvaz, Iran; Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical SciencesAhvaz, Iran.
Ahmad Farajzadeh
AF
Sheikh
Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical SciencesAhvaz, Iran; Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical SciencesAhvaz, Iran.
Azar D
AD
Khosravi
Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical SciencesAhvaz, Iran; Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical SciencesAhvaz, Iran; Molecular Biology Research Center, Baqiyatallah University of Medical ScienceTehran, Iran.
Hamed
H
Goodarzi
Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical SciencesAhvaz, Iran; Department of Infectious Diseases, Razi Teaching Hospital, Ahvaz Jundishapur University of Medical SciencesAhvaz, Iran.
Roohangiz
R
Nashibi
Department of Neurosurgery, Golestan Teaching Hospital, Ahvaz Jundishapur University of Medical SciencesAhvaz, Iran; Department of Neurosurgery, Tehran Medical Science Branch, Islamic Azad UniversityTehran, Iran.
Alireaza
A
Teimouri
Department of Radiology, Razi Teaching Hospital, Ahvaz Jundishapur University of Medical Sciences Ahvaz, Iran.
Azim
A
Motamedfar
Molecular Biology Research Center, Baqiyatallah University of Medical Science Tehran, Iran.
Reza
R
Ranjbar
Department of Infectious Diseases, Razi Teaching Hospital, Ahvaz Jundishapur University of Medical Sciences Ahvaz, Iran.
Sara
S
Afzalzadeh
Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences Ahvaz, Iran.
Mehrandokht
M
Cyrus
Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical SciencesAhvaz, Iran; Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical SciencesAhvaz, Iran.
Mohammad
M
Hashemzadeh
D001419:Bacteria / Q000145:classification* / Q000166:cytology / Q000235:genetics / Q000302:isolation & purification*; D001424:Bacterial Infections / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000382:microbiology / Q000473:pathology; D001431:Bacteriological Techniques / Q000379:methods*; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D015299:Discitis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000382:microbiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S
MRI; bacterial agents; biopsy; polymerase chain reaction; pyogenic spondylodiscitis