270. Detection of Anaerobic Bacteria Directly from Clinical Specimens with PCR followed by Electrospray Ionization Mass Spectrometry (PCR/ESI-MS) vs. Anaerobic Culture
Session: Poster Abstract Session: Diagnostic Microbiology; Novel Molecular Methods
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
Posters
  • PCRESI-MS Detection of Anaerobic Pathogens following Antibiotics (Abst - 39238 Presentation 270) - Final.pdf (320.2 kB)
  • Background:

    Anaerobic bacteria are common pathogens in soft tissue and pulmonary infections, yet reports of anaerobic infections are increasingly rare.  We conducted a prospective evaluation of anaerobic culture vs PCR-ESI-MS among inpatients with suspected anaerobic infection.

    Methods:

    Patients with suspected infection were prospectively identified.  Aerobic, anaerobic culture (anaerobic chamber) and PCR/ESI-MS were performed on specimens obtained following initiation of antibiotics.

    Results:

    PCR/ESI-MS detected one or more pathogens in 12/13 cases. Aerobic bacteria were detected in 9/13 cases; in 5 cases (Table 1).  Agreement between culture and PCR/ESI-MS occurred for 62% of specimens (8/13), but anaerobic results agreed in only 15 % (2/13) of cases. 

    Table 1

    Specimen

    Aerobic Culture

    Anaerobic Culture

    PCR/ESI-MS

    Level (GE)#

    DOT*

    Pleural fluid

    (-)

    (-)

    Streptococcus pneumoniae

    75

    11

    Brain abscess Drainage

    S. mitis / oralis

    S. mitis / oralis

    Streptococcus intermedius

    164

    2

    Right knee tissue

    (-)

    Staphylococcus  epidermidis

    S. epidermidis

    113

    1

    Right hip fluid

    (-)

    (-)

    (-)

    N/A

    0

    Epidural Abscess Fluid

    Propionibacterium acnes

    P. acnes

    P. acnes

    184

    1

    Liver abscess

    Drainage

    Corynebacterium spp

    S. intermedius

    Streptococcus spp

    Fusobacterium nucleatum

    40

    58

    1

    Submental abscess

    Swab from OR

    (-)

      Peptostreptococcus

    Porphyromonas gingivalis

    48

    2

    left ankle infection

    Swab from OR

    Enterobacter cloacae complex

    Same as aerobic

    Enterobacter cloacae

    105

    7

    Left hip tissue

     

    Escherichia coli

    Enterococcus faecalis

     

    Bacteroides fragilis

    Escherichia coli

    E. faecalis   (vanA positive) 

    B. fragilis

    3888

    138

    2153

    6

    Pleural fluid

     

    Staphylococcus aureus

    (-)

    S. aureus  (mecA negative)

    C. albicans

    Bilophilia wadsworthia

    72

    119

    15

    6

    Left ankle tissue

    from OR

     

    Streptococcus mitis / oralis

    (-)

    Streptococcus oralis

    Streptococcus infantis/peroris

    Finegoldia magna

    81

    58

    74

    31

    Bone biopsy

     

    Staphylococcus aureus

    (-)

    S. aureus  (mecA negative)

    Fusobacterium nucleatum

    7

    11

    6

    Pleural fluid

    (-)

    (-)

    Fusobacterium nucleatum

    188

    2

    *DOT– Days of therapy; # GE -Genome equivalents; OR = operating room

    Conclusion:

    PCR/ESI-MS may have a role in detection of anaerobic pathogens and may complement conventional anaerobic culture when specimens are obtained after the start of antibiotics, or are not delivered to the lab in a timely fashion.

    John Farrell, MD, University of Illinois College of Medicine, Peoria, IL; Infectious Disease, University of Illinois College of Medicine, Peoria, IL, Ranga Sampath, PhD, Ibis Biosciences, Inc., A Division of Abbott, Carlsbad, CA and Robert A. Bonomo, MD, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH

    Disclosures:

    J. Farrell, None

    R. Sampath, Ibis Biosciences, an Abbott Company: Employee, Salary

    R. A. Bonomo, None

    Findings in the abstracts are embargoed until 12:01 a.m. PST, Oct. 2nd with the exception of research findings presented at the IDWeek press conferences.