Liquid versus solid culture media for the microbiological diagnosis of eye infections: a retrospective comparative study
In brief
Liquid media detected growth in 72.5% of eye samples, versus 51% on agar
In this retrospective study of 102 ocular specimens, liquid broth grew organisms in 72.5% of samples, compared with 51% on solid media; 29 isolates appeared only in liquid cultures. The advantage persisted at seven days and after contaminants were excluded, supporting broth-first bedside inoculation when samples are scarce, though the findings need confirmation in other settings.
- Journal
- Diagnostic microbiology and infectious disease (Q2)
- Published
- 5 October 2026
- Study design
- Cohort / observational study
- Evidence level
- Level 3, Low (CEBM 3b)
- Authors
- Abdurrahman Sarmis, Omer Faruk Yilmaz, Serap Karaca, Busra Guneysu Yarar, Burak Ozben, Deniz Turan, et al.
- PMID
- 42843129
- DOI
- 10.1016/j.diagmicrobio.2026.117682
Why clinicians should know about it
- Picked for Microbiology (medical) (top studies of the week, 11 October 2026): Liquid vs solid media for ocular infection culture
Abstract
BACKGROUND: Ocular infections are an important cause of preventable vision loss, yet culture yield is limited by small specimen volumes and low bacterial loads. Comparisons of liquid and solid media in ocular infection are scarce. We evaluated four bedside-inoculated media: two liquid (Brucella broth, thioglycolate broth) and two solid (chocolate agar, 5% sheep blood agar). METHODS: We retrospectively analysed 102 ocular specimens collected between January 2023 and August 2025, each inoculated simultaneously onto all four media at the bedside. Because solid media were incubated for 7 days and liquid media for up to 21 days, positivity was compared at matched cut-offs of 24 hours, 48 hours and 7 days using McNemar and Cochran's Q tests, and all comparisons were repeated after excluding contaminant cultures. RESULTS: Growth was detected in 77.5% of specimens. At least one liquid medium was positive in 72.5% of cases versus 51.0% for solid media (p=0.0002). Brucella broth had the highest positivity (65.7%), followed by thioglycolate broth (60.8%); both solid media yielded 49.0%. Twenty-nine isolates, including Serratia marcescens, Streptococcus pneumoniae and Candida parapsilosis, were recovered exclusively from liquid media. At the matched 7-day cut-off, liquid media remained superior before (70.6% vs 51.0%; p=0.0005) and after (69.8% vs 53.1%; p=0.0022) excluding contaminants, with an identical odds ratio of 5.00. The solid media agreed almost perfectly (κ=0.922), indicating redundancy. CONCLUSIONS: Liquid media, particularly Brucella and thioglycolate broths, should be prioritised for bedside inoculation of ocular specimens. When specimen volume is limited, liquid-only inoculation avoids missing clinically significant pathogens.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.