[Normal conjunctival flora in healthy infants aged from 1 to 4 months].
OBJECTIVE
To investigate the normal conjunctival bacterial flora isolated from healthy infants aged from 1 to 4 months and to analyze its correlated factors.


METHODS
This was a cross-sectional study. From January to March 2009, 109 cases of healthy babies aged from 1 to 4 months were selected through simple random sampling when they accepted health examination provided by Tianjin Medical University Eye Center and Tianjin Women and Children's Health Center. Conjunctival swabs were taken from both eyes and inoculated onto blood agar plates. The isolated bacteria were classified professionally. The distribution of different bacteria was investigated as well as the possible correlated factors by using t-test, χ(2) test and binary logistic regression of SPSS 11.5.


RESULTS
26 cases of healthy babies (23.9%) got positive culture results which consisted 44 strains of ocular bacterial isolates. 25 strains were gram-positive cocci, while 18 strains gram-positive bacilli, and 1 strain gram-negative bacillus. The first three isolated bacteria were Diphthamide bacillus (17/44, 38.6%), Staphylococcus epidermidis (16/44, 36.4%), and Staphylococcus aureus (6/44, 13.6%). The two subtypes of Staphylococci coexisted with Diphthamide bacillus in 8 eyes of 36 eyes from which bacteria were isolated. The bacterial isolation rate through every month age group had no significant difference (χ(2) = 0.351, P > 0.05). There was no significant difference in the group of positive isolation (26 cases, 36 eyes) or negative isolation (83 cases, 166 eyes) through breast, formula or mixed feeding (χ(2) = 1.182, P > 0.05). The gender had no influence on the detection of bacteria (χ(2) = 0.001, P > 0.05). The birth weight, gestational age or examined age between the two groups had no significant difference (t = 0.078, t = 0.940, t = 0.686, P > 0.05). The gender, age, birth weight, gestational age and the way of feeding had no correlation with existence of conjunctival flora in these healthy infants (Wald χ(2) = 0.001, Wald χ(2) = 0.003, Wald χ(2) = 0.117, Wald χ(2) = 1.307, Wald χ(2) = 1.490, P > 0.05).


CONCLUSIONS
The normal conjunctival flora might establish during the initial months of little babies. Staphylococcus epidermidis and Diphthamide bacillus are the most common bacteria. Future studies should be conducted to make sure whether there would be some factors correlated with the culture results.
Tianjin Medical University Eye Center, Tianjin, China.
Ning
N
Hua
Wen-jiang
WJ
Ma
Jian-tao
JT
Wang
Ting
T
Shi
Xiao-rong
XR
Li
D003228:Conjunctiva / Q000382:microbiology*; D003353:Corynebacterium diphtheriae / Q000302:isolation & purification*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D013212:Staphylococcus epidermidis / Q000302:isolation & purification*