Outbreaks of Postoperative Bacterial Endophthalmitis Caused by Intrinsically Contaminated Ophthalmic Solutions -- Thailand, 1992, and Canada, 1993

Endophthalmitis is the syndrome of inflammation or infection of the ocular cavity and its adjacent structures and can result in severe sequelae, such as visual loss. Although most postoperative endophthalmitis following intraocular surgery is caused by infection with normal skin flora, cases associated with the intraoperative use of contaminated eye solutions or materials have been reported (1-3). This report summarizes outbreaks of postoperative bacterial (Pseudomonas aeruginosa or Bacillus spp.) endophthalmitis in Thailand and Canada; the outbreaks were associated with the intraoperative use of intrinsically contaminated basal salt solution (BSS) and hyaluronic acid. Thailand patients who had undergone extracapsular cataract extraction (ECCE) and intraocular lens implantation (IOL) in a hospital in Tak Province, Thailand, developed endophthalmitis less than or equal to 30 hours following surgery. P. aeruginosa, sensitive to gentamicin, amikacin, and piperacillin but resistant to kanamycin, ampicillin, tetracycline, chloramphenicol, and co-trimoxazole was isolated from intraocular fluid cultures from two of the patients. Because treatment with systemic and intravitreal antimicrobials failed, the infected eyes of all three patients were eviscerated.

An epidemiologic investigation by the Thai Field Epidemiology Training Program included a retrospective review of hospital records of all patients who had had cataract operations (predominantly ECCEs) in 1992, a case-control study to determine risk factors for infection, and environmental studies. No other patients with postoperative endophthalmitis were identified, and postoperative infections had not occurred in any of the six patients who had undergone other invasive ophthalmologic surgical procedures (scleral repair, evisceration, or eyelid operations) during September 29-October 2.

A case was defined as endophthalmitis in any patient who had had ophthalmic surgery at the hospital during September 29-October 2. Control patients were those who had had ophthalmic surgery performed by the surgeon who operated on the case-patient(s) on the same day. Risk for endophthalmitis was associated only with cataract surgery with IOL and the use of a BSS (three of four versus none of six; odds ratio {OR}=infinity, p=0.03, Fisher's exact test). P. aeruginosa with an antibiogram identical to that from cases was isolated from three of five unopened 100-mL bottles of BSS. P. aeruginosa was not isolated from cultures of other specimens, including specimens from hands of personnel, other ophthalmic medications and solutions, surgical instruments, or dressings.

During the year before this outbreak, BSS used in this hospital had been prepared in the hospital pharmacy. The contaminated bottles of BSS were from one batch prepared in the pharmacy on September 24 and had been distributed a few days later for use in the hospital operating room. A review of the procedures for production of BSS indicated that 100-cc bottles, their caps, and the tubes used for transferring the prepared BSS from the batch-container to the 100-cc bottles were routinely cleaned and placed under ultraviolet light overnight before use. After the 100-cc bottles were filled and capped, they were sterilized by autoclaving.

P. aeruginosa was isolated from swabs obtained from the inner surface of the solution-transfer tube. Solution from unused bottles was not cultured. In addition, on the day the implicated batch of BSS was autoclaved, the pressure in the steam autoclave was recorded to have been 10-12 pounds per square inch (psi) -- lower than the recommended standard of 15 psi. The inadequate sterilization, based on central supply records of the implicated batch of BSS, was detected only after the outbreak because the steam sterilizer was not monitored routinely with an indicator microorganism, and random samples of the implicated batch of BSS were distributed from the pharmacy. Canada

During July 19-23, 1993, of 42 patients who had undergone ECCE and IOL at a hospital in Montreal, Quebec, Canada, 14 had onset of endophthalmitis within 24-64 hours after surgery. Eleven of the 14 patients required vitrectomy and intravitreal administration of antimicrobial agents. Bacillus spp. (B. circulans {13 isolates} and B. brevis {one isolate}) were isolated from cultures of 32 intraocular fluid aspirates obtained from the 11 patients who underwent vitrectomy.

An epidemiologic investigation conducted by the hospital included a case-control study to determine risk and environmental factors for infection. A case (n=14) was defined as endophthalmitis in any patient who had had ophthalmic surgery at the hospital during July 19-23. Controls (n=28) were all other patients who had ophthalmic surgery performed at the same hospital during the same time period. Risk for endophthalmitis was not associated with any of the assessed potential risk factors, including exposure to specific surgical team members, medications, or solutions.

Cultures were obtained from samples of all solutions and ointments used pre-operatively; a random sample of all unidose or presterilized solutions used intraoperatively; other ophthalmic medications and solutions; surgical instruments; dressings; and operating-room air. Bacillus spp. (heavy growth) was isolated only from four previously unopened syringes containing commercially prepared hyaluronic acid solution from the same lot. The unopened syringes of hyaluronic acid were manufactured in Sweden and had been used at the hospital for approximately 5 months. A review of product-storage procedures in the hospital indicated that the commercially prepared hyaluronic acid syringes were stored at 64 F (18 C) in the hospital; the storage temperature recommended by the manufacturer was 36-46 F (2-8 C). Cultures of specimens obtained from the commercially prepared hyaluronic acid (labeled "sterile") yielded B. circulans (five isolates) and B. licheniformis (one isolate) by phenotypic methods at the Bureau of Microbiology, Laboratory Center for Disease Control, Health Canada, Ottawa.

Cataract surgery was suspended temporarily when the first case of postoperative endophthalmitis was recognized in a patient who had had surgery on July 19 and 64 hours later sought care in an emergency department for eye pain and blurred vision. Surgery was resumed after identification of the source of the infection. The hospital discontinued use of the implicated brand of hyaluronic acid on July 23; no additional cases of Bacillus spp. postoperative endophthalmitis have been detected.

Reported by: W Swaddiwudhipong, MD, T Tangkitchot, MD, N Silarug, MD, Dept of Community and Social Medicine, Dept of Ophthalmology, Mae Sot General Hospital, Tak; Field Epidemiology Training Program, Div of Epidemiology, Ministry of Public Health, Bangkok, Thailand. MA Miller, MD, Dept of Microbiology, Sir Mortimer B. Davis-Jewish General Hospital, J Chen, MD, Dept of Ophthalmology, Royal Victoria Hospital, Montreal, Quebec, Canada. Health and Welfare, Canada. Center for Drug Evaluation and Research, Food and Drug Administration. Hospital Infections Program, National Center for

Editorial Note

Editorial Note: Postoperative endophthalmitis is a rare complication of ECCE with IOL: in recent years in the United States, the incidence of endophthalmitis after ECCE with IOL has been less than 0.2% (4,5). Infection with gram-positive bacteria accounts for most such cases of endophthalmitis following ECCE with IOL, suggesting that exposure usually occurs during surgery as the result of introduction of organisms from the patient's skin or ocular surface tissues (6). However, infection with the same microorganism in multiple patients can result from a common source, such as contaminated saline, lens, or lens solution (1-3).

The outbreaks of postoperative endophthalmitis described in this report resulted from the intraoperative use of solutions believed to have been sterile. The microorganisms that caused these outbreaks -- P. aeruginosa and Bacillus spp. -- have been reported rarely as etiologic agents of postoperative endophthalmitis (4,7,8). In the outbreak in Thailand, inadequate sterilization may have allowed contaminants to survive in the containers and solution. In the outbreak in Canada, failure to maintain the commercially prepared hyaluronic acid at the manufacturer's recommended storage temperature may have facilitated proliferation of microbial contaminants to achieve concentrations exceeding minimum infectious doses for the eye.

In the United States, although the proportion of hospitals that produce their own ophthalmic solutions is unknown, most ophthalmic solutions used intraoperatively probably are commercially prepared. However, in 1990, an outbreak of postoperative endophthalmitis caused by P. aeruginosa was associated with exposure to or use of an intrinsically contaminated indomethacin ophthalmic preparation prepared in a community pharmacy (Food and Drug Administration {FDA}, unpublished data, 1990). Following this outbreak, on November 29, 1990, FDA issued a letter of alert to pharmacists regarding pharmacists' compounding of sterile drug products. Recognition of the potential for this problem also has been addressed in various guidelines for the preparation of sterile ophthalmic products (9,10).

Although outbreaks of postoperative endophthalmitis caused by microorganisms present in intrinsically contaminated solutions occur infrequently, such outbreaks underscore the needs for 1) strict quality control by the producers of such solutions, 2) strict adherence by the users of commercial products to product-storage procedures specified by manufacturers' instructions, and 3) heightened surveillance by ophthalmologists, hospital epidemiologists, and other infection-control personnel for cases of postoperative endophthalmitis associated with invasive ocular operations.

References

1. Ayliffe GA, Barry DR, Lowbury EJ, Roper-Hall MJ, Walker WM. Postoperative infection with Pseudomonas aeruginosa in an eye hospital. Lancet 1966;1:1113-7.

2. O'Day DM. Fungal endophthalmitis caused by Paecilomyces lilacinus after intraocular lens implantation. Am J Ophthal 1977;83:130-1.

3. McCray E, Rampell N, Solomon SL, Bond WW, Martone WJ, O'Day D. extraction and intraocular lens implantation. J Clin Microbiol 1986;24:625-8.

4. Kattan HM, Flynn HW, Pflugfelder SC, Robertson C, Forster RK. Nosocomial endophthalmitis survey: current incidence of infection after intraocular surgery. Ophthalmology 1991;98:227-38.

5. Menikoff JA, Speaker MG, Marmor M, Raskin EM. A case-control study of risk factors for postoperative endophthalmitis. Ophthalmology 1991;98:1761-8.

6. Sherwood DR, Rich WJ, Jacob JS, Hart RJ, Fairchild YL. Bacterial contamination of intraocular and extraocular fluids during extracapsular cataract extraction. Eye 1989;3:308-12.

7. Hemady R, Zaltas M, Paton B, Foster CS, Baker AS. Bacillus-induced endophthalmitis: new series of 10 cases and review of the literature. Brit J Ophthal 1990;74:26-9.

8. Weber DJ, Hoffman KL, Thoft RA, Baker AS. Endophthalmitis following intraocular lens implantation: report of 30 cases and review of literature. Rev Infect Dis 1986;8:12-20.

9. <1206>Sterile products for home use. In: United State Pharmacopeia. 23rd revision. Rockville, Maryland: United States Pharmacopeial Convention, Inc., 1995:1963-75.

10. Reynolds LA, Closson. Extemporaneous ophthalmic preparations. Vancouver, Washington: Applied Therapeutics, Inc, 1993.

+------------------------------------------------------------------- -------+ |             | | Erratum and Addendum: Vol. 45, No. 23 | |             | | SOURCE: MMWR 45(24);516 DATE: Jun 21, 1996 | |             | | In the article "Outbreak of Postoperative Endophthalmitis | | Caused by Intrinsically Contaminated Ophthalmic Solutions -- | | Thailand, 1992, and Canada, 1993" on page 492, in the second | | paragraph, the fourth line should read "... was recorded to have | | been 12 pounds per square inch (psi)...." | | Additional information regarding the outbreak in Thailand is | | available in: Swaddiwudhipong W, Tangkitchot T, Silarug N. An | | outbreak of Pseudomonas aeruginosa postoperative endophthalmitis | | caused by contaminated intraocular irrigating solution. Trans R Soc | | Trop Med Hyg 1995;89:288. | |             | +------------------------------------------------------------------- -------+

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