Infective endophthalmitis, as a serious ophthalmic emergency, can cause inflammation of intraocular tissue and even periorbital tissue in a short time, resulting in a sharp decline in vision and even enucleation. Therefore, it is very important to clarify the pathogenic causes and clinical characteristics [Li et al 4]. The Chinese PLA General Hospital is the largest medical center in North China, and the patients’ of which possess fine regional representation. This study involved the demographic, the microbial spectra and antimicrobial susceptibilities, and the relationship with VA during the past 30 years.
In terms of samples collection, the collection rate of vitreous biopsy was the highest in this study. While, that of ocular surface secretion which could have been easier to get was only nearly 1/3 of vitreous biopsy. On the one hand, it showed the proportion of vitrectomy to endophthalmitis was relatively high, on the other hand, it reflected samples of ocular surface secretion is prone to be polluted [Leal et al 5]. For the reason of possible pollution, vitreous biopsy is recommended as the first choice for endophthalmitis according to the guide to the microbiology laboratory for diagnosis of infectious diseases by the Infectious Diseases Society of America and the American Society for Microbiology and Laboratory branch of Beijing Medical Association [Miller et al 6; Laboratory branch of Beijing Medical Association 7]. But whether it’s vitreous biopsy, aqueous humor, or venous blood, the positive detection rate was low (all below 50%). So it highlights the importance of the microbial spectrum as perfect as possible [Grandi et al 8].
In this study, GPC was the commonest pathogen (39.3%), followed by GNB (32.0%), fungi (16.4%), and GPB (11.4%). The sequence was similar to the research from a tertiary hospital in Shanghai over a 10-year period and [Liu et al 9]. In a review of 25 years in India, Joseph et al. reported [Joseph et al 10] that the ratio of GPC, GNB, GPB and fungi was respectively 45.8%, 25.9%, 13.8% and 12.0%. While a report of a public health program from the Autonomous Community of Madrid showed that, the ratio of fungi was only 4.6% [Gentile et al 11]. Uppuluri et al. observed that Hispanics, Asians and Pacific Islanders, and Native Americans get a higher risk of being infected with fungi endophthalmitis than Whites, and the opinion of them is racial disparity makes the difference [Uppuluri et al 12].
At present, it is generally considered that vancomycin and ceftazidime are the best empirical antibiotic combination to treat bacterial endophthalmitis [Baig et al 13; Meyer et al 14]. This is consistent with our research result. To gram negative bacteria (whether GPC or GPB), antimicrobial susceptibility of vancomycin was 100%; to GNB, antimicrobial susceptibility of ceftazidime and imipenem were the same as the best (both 91.5%). Despite high antimicrobial susceptibility, imipenem and amikacin are rarely used in the treatment of patients with endophthalmitis. Risks associated with imipenem include seizures and nephrotoxicity, and risks associated with include nephrotoxicity, ototoxicity with deafness, and vertigo [Grzybowski et al 15]. But when it comes to intravenous administration, except for the susceptibility and the side effects, the blood-retinal barrier and therapeutic intraocular concentrations should also be considered [Das et al 16; Davies et al 17].
Endophthalmitis infected with GNC is rare and has not been indexed from multi-case studies. It is occasionally reported as individual case and the pathogens were all Neisseria [Bollam et al 18; Yusuf et al 19; Páez et al 20]. Similarly to the overwhelming majority of the reported, two cases in this study were both EnE. One was with liver abscess and diabetes, and the other was almost immunocompetent (without immunocompromise, intravenous drug abuse, et al.). But Goh reported a case of ExE with Neisseria because of glaucoma filtering bleb in 2020 [Goh et al 21].
Generally speaking, the prognosis of endophthalmitis is bad. Although VA of the total improved to 2.12 ± 0.93 with statistical significance at last, only 22.9% of eyes got relatively good VA (≤ 1.0). Besides, VA of ExE improved through the treatment but EnE did not. And VA of ExE was superior to EnE at last in this study. The outcome of EnE is worse than ExE, which is a common phenomenon. Balaskas [Balaskas & Potamitou 22] considered it was because of the more aggressive pathogens typically involved with this condition (i.e., more virulent organisms) and because of compromised host immunity and delay in diagnosis.
If it’s classified by pathogens, it could be seen with a better prognosis in endophthalmitis with GPC and fungi. While, there are a lot of contradictory researches on that, especially on fungus [Gounder et al 23; Simakurthy & Tripathy 24; Das et al 25; Ishikawa et al 26]. Factors related to final visual prognosis include control of diabetes and renal disease, immunocompromise condition, baseline visions, severe vitritis, and a longer interval from sepsis onset to ocular symptoms [Peng et al 27; Ang et al 28]. Analysing from the current study, especially multi-case study of tertiary referral center, we found that well internal medicine management created superior restoring conditions for endophthalmitis infected with fungus. Considering the hospital which provided these cases in this study is a large comprehensive hospital, experience on internal medicine management would work.
The main limitation of this study include: 1. Due to the limitations of patients’ economic affordability, some bacteria may not be identified, and anaerobic culture is not carried out routinely. 2. As a hospital-based study, selection bias might exist in the cases, who may represent more severe cases of infection.