Abstract
Endophthalmitis is a potential vision-threatening complication following surgical procedures (postoperative endophthalmitis [POE]), trauma (posttraumatic endophthalmitis [PTE]), and bacteremic seeding of the eye from a distant infection site (endogenous endophthalmitis [EE]). Several studies have revealed the polybacterial characteristics of endophthalmitis, which make the administration of antibiotics to treat the disease challenging. However, until now, the polybacterial communities of POE, PTE, and EE have not been precisely studied. Hence, the present study was designed to identify the bacterial community of endophthalmitis through 16S rRNA gene libraries. Of the 40 intraocular samples tested, 30 libraries were constructed with bacterial nested-PCR-positive samples. The obtained recombinant clones were screened through amplified rRNA gene restriction analysis (ARDRA) to identify unique clones. The multiple types of ARDRA patterns (
P
= 0.345) and diverse bacterial sequences (
P
= 0.277) within the libraries revealed the polybacterial nature of infection in POE, PTE, and EE. Moreover, to the best of our knowledge, this is the first report on polybacterial infection in EE. Gram-positive bacteria, including
Bacillus
spp. (
n
= 19),
Streptococcus
spp. (
n
= 18),
Staphylococcus
spp. (
n
= 6),
Exiguobacterium
spp. (
n
= 3),
Gemella
spp. (
n
= 2),
Enterococcus
spp. (
n
= 2), a
Lysinibacillus
sp. (
n
= 1), a
Clostridium
sp. (
n
= 1), and a
Nocardia
sp. (
n
= 1), and Gram-negative bacteria, including
Serratia
spp. (
n
= 18),
Pseudomonas
spp. (
n
= 10),
Enterobacter
spp. (
n
= 8),
Acinetobacter
spp. (
n
= 3),
Pantoea
spp. (
n
= 3), a
Haemophilus
sp. (
n
= 1), and a
Massilia
sp. (
n
= 1), were identified. Interestingly, among them, 10 bacterial species were not previously reported to be associated with endophthalmitis or other ocular infections. Besides, the presence of 4 unidentifiable clones suggests the possibility of novel organisms that might cause eye infections. Therefore, it is recommended that, in addition to the polybacterial nature of POE, PTE, and EE infections, the spectrum of the pathogenic bacterial community identified in this work should be considered while administering antibiotic therapy in suspected endophthalmitis cases.