Postoperative endophthalmitis caused by an Enterobacter species

Journal

of Hospital

Infection

Postoperative

G. Ertuijlrul

Departments

(1994)

26,

167717

1

endophthalmitis caused Enterobacter species

Mirza *, Sarper Karakiiqiik *, Mehmet and Abdiilkadir Caglayangilf

by an

Doganayi-

of *Ophthalmology and TInfectious Diseases, Erciyes Faculty of Medicine, Kayseri 38039, Turkey Accepted

for

publication

10 December

Uniaersit~

1993

Summary:

Six patients (aged 8 to 75 years) who were operated upon during the same day developed bacterial endophthalmitis on the following day; seven eyes were affected. Two patients had intracapsular cataract extraction, one extracapsular lens extraction, t\vo extracapsular cataract extraction with intraocular lens implantation and one repair of bilateral scleral or corneoscleral perforations. Vitreous cultures taken from six eyes were positive for an Enterobacter sp. Despite antibiotic treatment systemically, subconjunctivall) and intravitreally, four eyes had to be eviscerated, while two eves showed evidence of shrinkage (phthisis); only one eye retained useful vision (9110). Cotton swabs used during surgery, prepared manuallv from cotton wool moistened with saline, were identified as the source of-infection; the batch had not been subjected to the prescribed autoclaving process. The importance of proper sterile procedures in association with surgery is emphasized. Keywords: bacteriaceae;

endophthalmitis; Enterobacter

ocular spp.

infections;

nosocomial

infections;

Entero-

Introduction

Endophthalmitis is a disastrous complication of intraocular surgery, with an incidence of O.l-0.5% of operations.‘x2 Clinically, the major determinants of visual prognosis are the virulence of the organism and the rapidity of institution of appropriate therapy.” Every effort should be made to establish an aetiological diagnosis. Many agents have been reported to be responsible for intra-operative contamination, including cotton balls, svvabs, drapes, dressings, masks and gowns, rubber gloves, syringes, sutures, surgical instruments, eye drops and irrigation solutions.‘,” We report an outbreak of endophthalmitis caused by an Enterobacter sp. in seven eyes operated on during the same day; unsterile cotton vvool swabs used during operation were identified as the source of infection. Case reports

Seven eyes in six patients were operated upon at the Ophthalmology 167

Clinic

168

G. E. Mirza

et al.

of Erciyes University Faculty of Medicine on 18 September 1990. Five patients had elective surgery on one eye for cataract and one had an emergency operation on both eyes after injury in a road traffic accident. Endophthalmitis was diagnosed clinically in all these eyes on the second postoperative day. The characteristics of the patients and their management are summarized in Table I. On the day following surgery, all the patients had intense pain and mild periorbital swelling; all showed hypopyon in the anterior chamber and the fundus was invisible. A diagnosis of endophthalmitis was made. All the patients immediately received intravenous cephazolin (1 g 8-hourly) and oral prednisolone, 40 to 60 mg daily. Eye drops of tobramycin and dexamethasone were administered at hourly intervals and midriatic and cycloplegic eye drops 5 times daily. The patients also received daily subconjunctival injections of a mixture of gentamicin and dexamethasone and daily sub-Tenon’s injections of triamcinolone. A vitreous tap was performed in patients 1 to 5; in patient 6, the anterior chamber reaction was not so intense. The aspirate (0.3 ml) was sent for culture and microscopy. Gentamicin 0.3 mg, cephazolin 2.25 mg and dexamethasone 0.4 mg in a total volume of 0.3 ml were injected intravitreally. Microscopically, Gram-negative bacilli and a few cocci or diplococci were seen. On the fourth postoperative day, all the vitreous cultures yielded an Enterobacter sp. resistant to many antibiotics, but sensitive to amikacin, aztreonam, cefotaxime, ceftazidime, ceftriaxone and cefoperazone. The vitreous taps were repeated and 0.3 mg amikacin and 0.1 mg dexamethasone were infected intravitreally. Cultures were again positive for the Enterobacter sp., with similar antibiotic susceptibility. There was no sign of improvement and the anterior chambers rapidly refilled with purulent material. Ceftriaxone 100 mg was injected daily, subconjunctivally, in all eyes. On the 6th postoperative day, anterior chamber irrigation and vitreous tap with antibiotic injection (amikacin) were repeated. The cultures obtained from the anterior chamber were still positive for the Enterobacter sp. Despite subconjunctival ceftriaxone and intravitreal amikacin, the inflammatory process progressed and the patients generally lost light perception and had intractable pain. Four eyes (Patients 1, 2, 3 and 4) were eviscerated between the 20th and the 64th postoperative days. Gross examination and histology of all were similar: the vitreous cavity was filled with purulent and fibrotic material. Two eyes (patient 5) showed evidence of shrinkage (phthisis). Only one eye (patient 6) retained useful vision (9/10) after a follow-up period of 2 years. Microbiology

and

epidemiology

After recognition of the outbreak on the day following surgery, the operating room was closed and a thorough search for the source was instigated. Cultures were obtained from various possible sources including

Enterobacter

endophthalmitis

169

eye drops, ointments and irrigation solutions (balanced salt solutions), chlorhexidine and benzalkonium chloride solutions, the operating table, air ventilation pipes, tap water, the scrub-up area and various places in the operating room. Cultures vvere obtained from various materials in the sterile store such as sterile packs, drapes, operating suits, masks, caps, operation gloves, dressings, sutures and disposable syringes. Culture of the soiled surgical instruments used on the day of operation was not possible since they were cleaned and re-sterilized immediately after the operations. However, cultures were obtained from the instruments inside the tin tray immediately after autoclaving to check the effecti\.eness of sterilization. Most of the cotton swabs inside the closed autoclav,e drum vvere used up during the operations; cultures could be obtained only from those remaining inside the drum. Svvabs outside the drum w:ere not available for culturing. ,411 specimens were inoculated on blood agar and EnIB agar and incubated overnight at 37°C. Only one culture exhibited a profuse growth: this was obtained from the remaining cotton svvabs inside the closed drum. The isolates from the cotton swabs and from vitreous aspirates exhibited common biochemical and antimicrobial susceptibility properties; they were susceptible to amikacin, aztreonam, cefotaxime, ceftazidime, ceftriasone, and cefoperazone, but resistant to ampicillin/sulbactam, cefurosime, gentamicin, netilmicin, and tobramycin. The bacterial isolates were identified as Entevobactev sp. according to standard criteria;” speciation \vas not carried out. In 1990, at the time of the outbreak, swabs vvere prepared in the clinic b> immersing small pieces of cotton vvool in physiological saline and making small rolls (approximately 5 cm) manually. Those cotton svvabs vvere put into the autoclave drum, the lid was closed and an indicator tape (autoclav-e tape, 3M, USL4) attached on top of the lid before autoclaving. Unfortunately, on the operation morning, the personnel failed to remove the used indicator tape from the top of the drum and attach a new one. The drum with the used tape, and its unsterile contents, was therefore returned to the operating room vvithout being autoclaved; it was concluded that the definite source of infection vvas those unsterile cotton swabs used during all operations on that day. Sterilization processes in the hospital were inspected, the personnel were instructed in order to minimize human error, and specific measures were taken to prevent further nosocomial infections. Discussion

Despite improvements in intraocular surgery, endophthalmitis still remains a catastrophic hospital infection. In one survey of endophthalmitis, Staphylococcus epidermidis was found to be the most common causative

170

G. E. Mirza

et al.

organism. It was concluded that 75% of postoperative endophthalmitis was caused by Gram-positive bacteria, 16% by Gram-negative bacteria and 8% by fungi.7 Patients with diabetes mellitus are generally at higher risk of developing infective endophthalmitis. * Our patients did not have diabetes or any other significant systemic disorder. Antibiotics penetrate poorly into the vitreous humour after periocular or systemic administration. 9,10Although some authors suggest conventional therapy without intra-vitreal injection,“‘12 intravitreal injections appear to be of the greatest value in treating cases of endophthalmitis due to highly virulent organismq4 doses that are non-toxic to the retina have been studied in detail.13 Although cephalosporins are among the commonest agents to be injected intravitreally before the results of microbiological investigation are known,14 bacteria encountered in hospital, including Enterobacter spp., may exhibit resistance to these agents. 4 The Enterobacter sp. obtained from our vitreous aspirates was resistant to cefuroxime but sensitive to cefotaxime, ceftazidime, cetriaxone, and cefoperazone. Satisfactory results have been reported elsewhere with parenteral ceftriaxone.” We also performed daily subconjunctival injections of ceftriaxone after the antibiotic sensitivity of the strain was known. Intravitreal amikacin has been used in endophthalmitis patients with success. I6 Since the Enterobacter sp. from our aspirates was also susceptible to amikacin, we injected this antibiotic intravitreally; however, it failed to inhibit bacterial growth, as demonstrated by repeat cultures. Vitrectomy is both diagnostic and therapeutic in endophthalmitis.4 Although we did not perform vitrectomy with a surgical vitrector, we replaced a significant amount of vitreous with antibiotics during aspiration and antibiotic injection. Despite every effort, visual outcome may be poor for the patients once endophthalmitis develops, because microorganisms in hospital infections are highly virulent and resistant to most antibiotics. It is best to avoid the infection before it occurs. About 7000 eye operations have been performed since the establishment of our clinic in 1975, using similarly prepared cotton swabs and applying the same sterilization method; these are the only casesof nosocomial endophthalmitis that we have encountered. The problem was caused by a failure of staff to carry out the prescribed sterilization process. Disposable (cellulose) sterile sponges have now become more available locally and have been used in all eye operations since this outbreak occurred. We conclude that any material used during ocular surgery should be carefully sterilized before each operation and procedures utilized that remove any chance of human error. When an outbreak occurs in a clinic, appropriate treatment must be started without delay and urgent and strenuous efforts made to identify the source of infection to eliminate the risk of any further occurrence.

75

64

SO

8

8

41

2

3

4

5

5

6

ECCE, Extracapsular I,P, light perception;

52

Xge

1

Patient No

F

M

hl

F

M

M

F

Sex

cataract

I.5 mfc

0.3

LP

15cmhm

LP

lmhm

ICCE,

30 cm fc

Preoperative visual acuity

I. Characteristics

Intraocular lens; conj, conjunctival.

perforation

Cortical and posterior subcapsular cataract

Scleral

Corncosclcral perforation

Mature

Posterior subcapsular cataract Entumescent cataract

Entumescent cataract

Preoperative diagnosis

cataract extraction; IOL, NLP, nu light percrption;

R

L

R

L

R

R

I,

Eye side

Table

repair

perforation

cataract

ICCE with alpha-chymotrypsin zonulolysis

Scleral repair

Corneoscleral perforation

extraction;

sp.

sp.

fc, finger

counting;

Vitreous culture not obtained; conjunctival culture negative

Enterobacter

Enterobacter

sp.

Enterobacter

ECCE

+ IOL

sp.

Enterobacter

sp.

ICCE

Enterobacter

Culture

sp.

+ 101,

of the patients

Enterobacter

ECCE

ECCE

Operation

management

Intracapsular

and

hm,

hand

Eviscerated 51 st postoperative Eviscerated 20th postoperative Eviscerated 64th postoperative Eviscerated 22nd postoperative Eye ball shrinkage (phthisis), Eye ball shrinkage (phthisis), 0.9

Outcome final visual

day

day

day

day

movements;

LP

NLP

on

on

on

on

and acuity

172

G. E. Mirza

et al.

References 1. Hassan IJ, MacGowan AP, Cook SD. Endophthalmitis at the Bristol Eye Hospital: an 1 l-year review of 47 patients. J Hosp Infect 1992; 22: 271-278. 2. Koul S, Philipson A, Philipson BT. Incidence of endophthalmitis in Sweden. ACTA Ophthalmol 1989; 67: 499-503. 3. Mandelbaum S, Forster RK. Bacterial Endophthalmitis. In: Fraunfelder FT, Roy FH, Eds. Current Ocular Therapy. Philadelphia: W. B. Saunders Co. 1990; 533-535. 4. Jaffe NS, Jaffe MS, Jaffe GF. Endophthalmitis. In: Jaffe NS, Jaffe MS, Jaffe GF, Eds. Cataract surgery and its complications, 5th edn. St. Louis: CV Mosby 1990; 506-542. 5. Erbag 0, Acar NS, Aksaray S, Duman S. 18 Olguda g&de gelisen iatrojenik infeksiyonlar (Iatrogenic eye infections occurring in 18 cases). Congress Book, Fourth National Infectious Diseases Congress, 27-30 April 1993 Izmir, Turkey, 1993; 22. 6. Farmer JJ, Kelly MT. Enterobacteriaceae. In: Balows A, Hausler Jr. WJ, Herrman KL, Isenberg HD, Shadomy HJ Eds. Manual of Clinical Microbiology. Washington DC, American Society for Microbiology 1991; 360-383. 7. Driebe WI, Mandelbaum S, Forster RK, Schwartz LK, Culbertsor WW. Pseudophakic endophthalmitis: diagnosis and management. Ophthalmology 1986; 93: 442-448. 8. Kattan HM, Flynn Jr HW, Pflugfelder SC, Robertson C, Forster RK. Nosocomial endophthalmitis survey. Current incidence of infection after intraocular surgery. Ophthalmology 1991; 98: 227-238. 9. Miglioli PA, Dorigo MT. Antibiotic levels in aqueous and vitreous humor after intraocular administration. Chemotherapy 1989; 35: 406-409. 10. Barza M. Doft B. Lvnch E. Ocular oenetration of ceftriaxone. ceftazidime. and vancomydin after subdonjunctival injechon in humans. Arch 0ph;halmol 1993: 111: 492-494. 11. Akyol N, ijnliicerci HC, Aydm I, Giilgor, A. Konvansiyonel yolla endoftalmi tedavisi. Tiirk Oftalmoloji Gazetesi 1990; XX(S): 324-327. 12. Heaven CJ, Mann PJ, Boase DL. Endophthalmitis following extracapsular cataract surgery: a review of 32 cases. BrJ Ophthalmol 1992; 76: 419-423. 13. Peyman GA, Schulman JA. Intravitreal drug therapy. Jpn J Ophthalmol 1989; 33: 392-404. 14. Forster RK. Endophthalmitis. In: Duane TD, Jaeger EA, Eds. Clinical Ophthalmology (Vol. 4/Ch. 24) Philadelphia: Harper & Row Publishers 1986; l-20. 15. Wang FD, Wang LS, Liu YC, Liu CY, Lin CL, Wong WW. Successful treatment of metastatic endophthalmitis. Case reports. Ophthalmologica 1989; 198: 124128. 16. Talamo JH, D’Amico DJ, Kenyon KR. Intravitreal amikacin in the treatment of bacterial endophthalmitis. Arch Ophthalmol 1986; 104: 1483-1485.