Related Experiment Video
Updated: Jul 28, 2025
Author Spotlight: Oral Candida Diagnosis to Advance Clinical Treatment Regimen for pSS Patients
Published on: March 1, 2024
Conjunctival sac flora and drug susceptibility analysis in normal children in East China
Mingming Jiang1,2,3, Jing Zhang4,5,6, Xiaomei Wan1,2,3
1Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, No.5 Yan'erdao Road, Shinan District, Qingdao, Shandong, China.
Insights
Conjunctival sac flora in children is mainly Gram-positive cocci, with Staphylococcus epidermidis increasing with age. This flora is generally sensitive to quinolone antibiotics like moxifloxacin.
Area of Science:
- Ophthalmology
- Microbiology
- Pediatrics
Background:
- The conjunctival sac microbiome plays a role in ocular health.
- Understanding the distribution and antimicrobial susceptibility of conjunctival flora in children is crucial for effective treatment of eye infections.
Purpose of the Study:
- To investigate the distribution characteristics of conjunctival sac flora in normal children in East China.
- To assess the susceptibility of common topical antimicrobial agents against these microorganisms.
Main Methods:
- Microorganism cultures of the conjunctival sac were analyzed in 1258 normal children (2516 eyes).
- The microdilution method was used to determine minimum inhibitory concentration (MIC) values for drug susceptibility testing.
- Exclusion criteria included ocular surface diseases and recent topical antimicrobial use.
Main Results:
- The incidence of conjunctival sac microorganisms was 32.87%, with Gram-positive cocci being the most prevalent (91.54%).
- Staphylococcus epidermidis (52.12%), Streptococcus (12.09%), and Staphylococcus aureus (10.76%) were the most frequently detected bacteria.
- Staphylococcus epidermidis showed increased prevalence with age and high sensitivity to gatifloxacin, while Streptococcus exhibited high resistance to tobramycin.
Conclusions:
- Conjunctival sac flora in children is dominated by Gram-positive cocci, primarily S. epidermidis, S. aureus, and Streptococcus.
- S. epidermidis prevalence increases with age, and Streptococcus is more common than S. aureus in children aged 0-6 years.
- The flora is generally sensitive to quinolones (moxifloxacin, gatifloxacin), but Streptococcus shows high resistance to tobramycin.
Purpose:
To investigate the distribution characteristics of conjunctival sac flora and assess the susceptibility of commonly used topical antimicrobial agents in normal children under the age of 18 in East China.
Methods:
In 2019, a study was conducted at Qingdao Eye Hospital of Shandong First Medical University to analyze the microorganism cultures of conjunctival sac in 1258 normal children (2516 eyes; average age, 6.21 ± 3.78 years) in East China. Exclusion criteria included children with ocular surface diseases and those who had used any topical antimicrobial agents recently. The microorganism species in the conjunctival sac were analyzed using the M-38A protocol (microdilution method; investigators read the minimum inhibitory concentration [MIC] values) by the Clinical and Laboratory Standards Institute to determine drug susceptibility.
Results:
The incidence of conjunctival sac microorganism in children was 32.87% (827/2516), a total of 541 cases (male 293, female 248). Children with conjunctival sac flora in a single eye were 255 and in both eyes were 286 (no statistical difference, P > 0.05). The concordance rate of children with binocular conjunctival sac flora was 32.16% (174/541; male 84, female 90). A total of 42 species of bacteria were detected. Children with Gram-positive cocci accounted for the highest proportion, 91.54% (757/827). The top three bacteria with the highest detection rates were Staphylococcus epidermidis (S. epidermidis; 52.12%), Streptococcus (12.09%), and Staphylococcus aureus (S. aureus; 10.76%). Streptococcus mitis (5.20%) accounted for the highest proportion of Streptococcus.S. epidermidis had the highest proportion in all age groups and was positively correlated with age (r = 0.89, P = 0.03). Before six years of age, the streptococcal proportion(mainly S. mitis) was greater than that of Staphylococcus aureus. The drug susceptibility analysis showed that S. epidermidis was most sensitive to gatifloxacin (98.61%), while it had the highest resistance rate to erythrocin (87.94%). S. aureus had the highest susceptibility to moxifloxacin (100%). Streptococcus was most sensitive to moxifloxacin (96.97%) and had the highest resistance rate to tobramycin (92.93%).
Conclusions:
Conjunctival sac flora in children was dominated by Gram-positive cocci, mainly S. epidermidis, S. aureus, and Streptococcus. S. epidermidis increased with age; the proportion of Streptococcus was higher than S. aureus among children aged 0-6 years. The typical conjunctiva sac flora was generally sensitive to quinolones, such as moxifloxacin and gatifloxacin; Streptococcus displayed high resistance to tobramycin antibiotics; and the female children had higher resistance to tobramycin than the male children.
Related Concept Videos
01:20Sputum Studies II: Culture and Sensitivity
Sputum culture and sensitivity is a medical procedure used to diagnose bacterial infections in the respiratory tract and select the most appropriate antibiotics for treatment. This process involves analyzing sputum samples of thick and opaque secretions produced in the lungs and airways. These samples are collected from patients and then sent to the laboratory for analysis.
The test can identify various pathogens responsible for respiratory infections, including Streptococcus,...
01:26Sputum Studies I: Gram Stain, cytology, and Acid-fast smear and culture
Gram Stain
The Gram Stain is an integral part of sputum studies. It involves the staining of sputum, which permits...