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Professor Nie Yuhong: Reflections on a Case of Bacillus cereus Endophthalmitis

Posting time:2022-10-06 02:38:55

Professor Nie Yuhong: Reflections on a Case of Bacillus cereus Endophthalmitis

Editor's note: Endophthalmitis is a serious infectious eye disease with abrupt onset and rapid progression, which can lead to a sharp decline in vision, severe lack of light perception or loss of the eyeball. Bacillus cereus endophthalmitis is one of the most serious bacterial endophthalmitis. Most of them are caused by trauma and severely damage the eye tissue. Even after effective treatment, the final vision will still be lost within 48 hours, so the prognosis is extremely poor. . Recently, Professor Nie Yuhong from the People's Hospital of Wuhan University treated 3 patients with Bacillus cereus endophthalmitis. All cases underwent vitrectomy + foreign body removal + silicone oil filling + vitreous cavity injection, but 3 patients had no light after surgery. Sensation, 1 patient eventually enucleated the eyeball, 2 patients eventually became dependent on silicone oil, the eyeball was atrophied, and the cornea was completely white and cloudy. Professor Nie took a patient as an example to analyze the pathogenic mechanism, clinical signs and treatment of Bacillus cereus endophthalmitis in detail. A patient with Bacillus cereus endophthalmitis, male, 49 years old. Chief Complaint: Foreign body splash in left eye for 32 hours. History of present illness: The patient accidentally splashed a foreign object into his left eye when the lawnmower was mowing the lawn at about 10 am yesterday. He developed pain in the left eye early this morning, blurred vision, headache and nausea. Past history: None special. Auxiliary examination: orbital CT in the outer hospital showed a foreign body in the left eyeball. Specialist examination: Treatment: emergency left eye PPV + lens resection + foreign body removal + gas-liquid exchange + silicone oil filling + intravitreal injection (vancomycin and ceftazidime). Corneal edema was seen during the operation. After the corneal epithelium was cured, the hyphema and hemorrhage were washed out. No lens was seen in the pupil area. , Ultrasound crushed the lens, removed the foreign body with intraocular forceps, filled the vitreous cavity with silicone oil, and injected vancomycin and ceftazidime injections. Intraoperative sampling for bacterial culture and high-throughput sequencing showed that Bacillus cereus was infected. Bacterial culture results High-throughput sequencing results Follow-up: Despite active surgery and anti-infective treatment, the patient still has no light perception, corneal leukoplakia, and mild atrophy of the eyeball. Postoperative follow-up of patients with anterior segment pictures Extended thinking: Bacillus cereus endophthalmitis Bacillus cereus is a saprophytic bacteria that exists in soil, sewage, etc. Most of them are related to self-limiting food poisoning cases, and also exist in normal conjunctiva sac, generally not pathogenic. It belongs to G+ bacteria, can form spores, can resist drying, and survive at 8-50℃. Compared with Bacillus infections in other parts of the body, Bacillus cereus infection in the eyes can cause an extremely strong inflammatory response and is a more destructive bacterium that releases a variety of enzymes and exotoxins, which can cause damage within 24 hours. irreversible infection. The picture is quoted from the document The cereus matter of Bacillus endophthalmitis.[J] .Exp Eye Res, 2020, 193: 107959. (A) Bacillus cereus Gram stain (400X). (B) Flagella staining (1000X). (C) 1 μL of Bacillus cereus was dropped onto tryptic soy agar (TSA) + 5% sheep blood agar, incubated at 37°C for 18 h, and colonies with hemolytic characteristics were observed at each inoculation point. (D) Transmission electron microscopy (TEM) of Bacillus cereus. Black arrows indicate flagella and white arrows indicate fimbriae. Pathogenic Mechanisms Bacteria replicate rapidly in the body. Bacteria produce enzymes and toxins: hemolysin (HBL), non-hemolytic enterotoxin (NHE), matrix metalloproteinases, phospholipases, etc. Activates inflammatory response pathways and disrupts the blood-retinal barrier. The picture is quoted from the document The cereus matter of Bacillus endophthalmitis.[J] .Exp Eye Res, 2020, 193: 107959. Bacillus cereus endophthalmitis model. (A) Bacillus cereus infection of the eye following ocular trauma or surgery. (B) Bacteria grow rapidly in the vitreous cavity and migrate to the retina. (C) Bacillus cereus produces bacterial toxins and enzymes. These products lead to dysfunction and increased permeability of the blood-retinal barrier. (D) Bacterial envelope components activate the TLR pathway. (E) Activation of the TLR pathway leads to the production of pro-inflammatory mediators that recruit inflammatory cells (PMNs) to the eye. Clinical manifestations and signs The clinical manifestations and signs of Bacillus cereus endophthalmitis are similar to endophthalmitis caused by other bacteria, but occur more rapidly. Ocular clinical manifestations: severe eye pain, decreased visual acuity. Clinical signs of the eye: high eyelid and periorbital swelling, conjunctival hyperemia and edema, massive yellow secretions, corneal edema, anterior chamber cells, hypopyon, and proptosis, which can progress to panophthalmitis and orbital cellulitis. Corneal annular infiltrates are typical clinical signs of Bacillus endophthalmitis. The time between injury and vision deterioration is usually less than 48 hours, and light perception is often absent by the time of presentation. Systemic symptoms: fever, leukocytosis. Treatment is found in experimental Bacillus cereus endophthalmitis, early treatment (4h after infection) is effective, and the treatment effect is poor after 6h, so the treatment time window is very short, and timely and correct treatment is very important. Sensitive to vancomycin, levofloxacin, ofloxacin, tobramycin, and neomycin. Intravitreal injection: vancomycin (1mg/0.1ml). Fluoroquinolone and aminoglycoside antibiotics are used systemically. With the development of vitrectomy technology, the current rate of enucleation has decreased significantly. Professor Nie concluded that Bacillus cereus endophthalmitis has a rapid onset, early diagnosis and active treatment measures can save some vision, but the overall prognosis is poor. Penetrating wounds combined with soil-contaminated intraocular foreign bodies are risk factors for Bacillus cereus infection. If Bacillus cereus endophthalmitis is suspected, surgery should be performed as soon as possible. Vitrectomy combined with silicone oil filling can help patients save the eyeball. Expert Profile Nie Yuhong, MD, Deputy Chief Physician, graduated from the Zhongshan Ophthalmology Center of Sun Yat-sen University, and presided over 1 National Natural Science Foundation of He has rich clinical experience in macular hole, epimacular membrane, etc.), ocular trauma and other fundus diseases.

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