Table 11.
Laboratory Diagnosis of Periocular Structure Infections/Conjunctivitis, Orbital and Periorbital Cellulitis, and Lacrimal and Eyelid Infections
| Etiologic Agents | Diagnostic Procedures | Optimum Specimens | Transport Issues and Optimal Transport Time |
|---|---|---|---|
| Bacteria | |||
|
Haemophilus influenzae
Streptococcus pneumoniae Staphylococcus aureus Moraxella catarrhalis and other spp Streptococcus pyogenes Escherichia coli Other Enterobacteriaceae Neisseria gonorrhoeae |
Gram stain Aerobic bacterial culture |
Conjunctival swab | Swab transport device, RT, 2 h |
|
Actinomyces spp Other anaerobic bacteria (rare cause of canaliculitis) |
Anaerobic bacterial culture | Conjunctival scraping or biopsy | Sterile anaerobic container, RT, immediately |
| Chlamydia trachomatis | Direct fluorescent antibody stain NAATa,b |
Conjunctival swab | Virus swab transport device, RT, 2 h |
| Viruses | |||
| HSV | HSV NAAT HSV culture |
Conjunctival swab | Virus swab transport device, RT, 2 h |
| VZV | VZV NAAT | Conjunctival swab | Virus swab transport device, RT, 2 h |
| Adenovirus | Adenovirus NAAT | Conjunctival swab | Virus swab transport device, RT, 2 h |
| Herpes B virus | c | ||
Abbreviations: HSV, herpes simplex virus; NAAT, nucleic acid amplification test; RT, room temperature; VZV, varicella zoster virus.
aNAATs for detection of C. trachomatis have not yet been approved in the United States for use with conjunctival swab specimens. Individual laboratories, however, may have validated NAATs for examination of specimens obtained from patients with conjunctivitis, and studies suggest that NAATs are more sensitive than cultures.
bUse of NAAT for detection of C. trachomatis is considered an “off-label” use of this test. Laboratories that offer such testing must conduct in-house validation of these assays before offering NAAT as a diagnostic test.
cCulturing of specimens thought to harbor herpes B virus (primate origin) requires use of biosafety level 4 precautions in the laboratory, and testing is almost always referred to a specialized reference laboratory. Consult the laboratory when herpes B virus is suspected.