Clinical and Microbiological Profile of Bacillus Keratitis

Kushal K. Choudhuri, M.D., Savitri Sharma, M.D., Prashant Garg, M.S., and Gullapalli N. Rao, M.D.

Purpose. To examine the clinical and microbiological profile of as well as osteomyelitis and surgical wound infection. The fre- Bacillus keratitis. Methods. A retrospective review was done of all quent association of Bacillus in causing severe posttraumatic en- medical and laboratory records of patients with infectious keratitis dophthalmitis has been well documented in the literature.1 How- in an urban tertiary level eye-care center in South India between ever, descriptions of corneal ulcer caused by Bacillus are hard to January 1991 and June 1997. Results. Nineteen eyes of 17 patients come by, and the literature consists of only a few case reports.2–4 having microbiologically proven Bacillus keratitis were reviewed. This study was undertaken to report the clinical and microbiologic The mean age of the patients was 32.64 years (range, 3–70). The duration of symptoms ranged from 1 day to 3 months, with 11 eyes profile of this unusual clinical entity in a large series of patients. seen within a week of onset of symptoms. Trauma (five eyes), lagophthalmos (two eyes), topical corticosteroid therapy (one eye), bullous keratopathy (two eyes), previous corneal scars (two eyes), MATERIALS AND METHODS and diabetes (one eye) were identified as predisposing factors. Severe corneal features, disproportionate to the duration of symp- The medical charts and laboratory records of all patients with toms, were present in most of the eyes. Gram stain of corneal culture-proven Bacillus keratitis seen at our institute between scrapings showed variably stained bacilli in eight (42.1%) cases. January 1991 and June 1997 were retrospectively reviewed. Only Polymicrobial infection was present in six eyes (two fungal, four those with a significant bacterial growth from corneal scrapings bacterial). Of the 16 isolates tested for in vitro antibiotic suscep- were considered for analysis. According to institute protocol, all tibility, 100% were sensitive to gentamicin, 15 (93.75%) were sensitive to ciprofloxacin and norfloxacin, 14 (87.5%) were sen- cases of infectious keratitis, after relevant history recording and sitive to chloramphenicol, and 10 (62.5%) were sensitive to cefa- careful slit-lamp examination, were subjected to scraping of the zolin. Whereas 12 (63.1%) eyes required only medical therapy, ulcer at the slit-lamp by using a sterile no. 15 blade on Bard Parker adjunctive procedures were required in seven (36.8%) eyes. The handle under 4% lignocaine topical anesthesia. From the material ulcers healed (mean time to healing, 37.4 ± 28.6 days) in 16 eyes obtained, three smears were prepared: 10% potassium hydroxide (lost to follow-up, three). Visual acuity had improved after treat- (KOH) with calcofluor white, Gram, and Giemsa stains. Material ment in 10 (71.4%) of 14 eyes in whom vision could be recorded. also was directly inoculated on various culture media depending Conclusion. Bacillus is an unusual pathogen in the clinical setting on the amount available. These included two sheep-blood agar of infectious keratitis. The infection is mostly amenable to treat- (aerobic and anaerobic incubation), one chocolate agar (5% CO ), ment with commonly used antibiotics, and the final outcome is 2 and one each of Sabouraud’s dextrose agar, brain heart infusion often satisfactory. Escherichia Key Words: Infectious keratitis—Bacillus—Treatment out- broth, thioglycolate broth, and nonnutrient agar with come—Microbiology. coli overlay. All media except Sabouraud’s agar were incubated at 37°C. Sabouraud’s agar was incubated at 27°C. All plates and broth media were incubated for 7 days, after which if the broth media were still negative, a terminal blind subculture onto chocolate agar was done. Culture isolates were identified by standard Over the past two decades, organisms of the genus Bacillus microbiologic procedures. Sensitivity to gentamicin, ciprofloxa- other than B. anthracis have increasingly been recognized as im- cin, chloramphenicol, norfloxacin, and cefazolin was determined portant pathogens in the causation of food poisoning and other by using the Bauer–Kirby disk-diffusion method. A significant nongastrointestinal infections, particularly in drug addicts, in the growth was defined as (a) growth in any one medium correlating immunosuppressed, and in those with prosthetic cardiac valves. with the smear report, (b) growth of the same organism in two They are known to cause septicemia, meningitis, and endocarditis solid media, (c) confluent growth of the organism in one solid medium at the inoculum site, or (d) repeated isolation of the same Submitted March 31, 1999. Revision received June 17, 1999. Accepted organism from another sample from the same lesion. June 24, 1999. In most cases the treatment was started based on the smear From the Cornea Service (K.K.C., P.G., G.N.R.) and Jhaveri Microbi- report. In case of a positive smear showing Bacillus organisms, ology Centre (S.S.), L.V. Prasad Eye Institute, L.V. Prasad Marg, Banjara fortified cefazolin (5%) and gentamicin (1.4%) was started every Hills, Hyderabad, India. Address correspondence and reprint requests to Dr. S. Sharma, L.V. minute for 5 min and then every 30 min for the first 72 h, after Prasad Eye Institute, L.V. Prasad Marg, Banjara Hills, Hyderabad 500 034, which it was tapered according to the clinical response. In the India. E-mail: [email protected] absence of smear positivity, ciprofloxacin (0.3%) was started at a

301 302 K.K. CHOUDHURI ET AL. similar dosage. Treatment was modified according to the sensitiv- ondary to leprosy. One patient (5) was using topical corticosteroids ity pattern obtained from the laboratory if response to the medi- and occasionally antiviral drops for recurrent herpes simplex kera- cation was inadequate. Adjunctive procedures like tissue adhesive titis. Two eyes (14 and 17) had postcataract surgery bullous ker- application, tarsorrhaphy, vitreous sampling, and intraocular anti- atopathy, and two eyes (7 and 8) had previous corneal scars. Pa- biotic injections and therapeutic penetrating keratoplasties (PKs) tient 19 was diabetic. None of the patients wore contact lenses, and were performed whenever necessary. Antifungal antibiotics were none had chronic dacryocystitis. added in case of mixed infection with fungus. The characteristics The maximal dimensions of the epithelial defects and infiltrates of the ulcer at initial presentation, the microbiologic profile, and are tabulated in Table 2. The ulcers were mostly central (seven) response to treatment were analyzed. These form the basis of our and paracentral (seven) in location, with only two being peripheral. report. The ulcers >9 mm in diameter (three eyes) were not included in this analysis, as it was difficult to guess the initial location of the lesion in these eyes. Thirteen (68.42%) of the infiltrates extended to the posterior one third of the stroma, with only six (31.57%) RESULTS confined to the anterior two thirds of the stroma. A ring infiltrate was seen in two eyes (6 and 15). Eye 11 had a pigmented plaque, Nineteen eyes of 17 patients were identified for the analysis. and eye 17 had only a faint granular superficial infiltration. Three Two patients had simultaneous bilateral corneal ulcers (eyes 2, 3, eyes had perforation (3, 9, and 16), whereas two more (10 and 13) 10, 11). The patients varied in age from 3 to 70 years (mean, 32.64 perforated within 1 week of starting therapy. Significant anterior years; median, 30 years). The age distribution was triphasic, with chamber reaction was seen in eight eyes. Two eyes (10 and 16) had four patients younger than 10 years, four patients older than 60 exudates filling up the entire anterior chamber (Fig. 1). Hypopyon years, and nine patients aged between 18 and 45 years. in the other eyes ranged in height from 0.5 to 3 mm. Visual acuity Fourteen (82.35%) of these were male and three were female at presentation is shown in Table 1 and Fig. 2. Endophthalmitis subjects. Patient 7 complained of a whitish opacity developing was clinically suspected in three eyes (15, 16, and 19). Two eyes over the cornea in an otherwise blind eye; the rest complained (10, 11) of another patient had severe polymicrobial keratitis. The primarily of pain, redness, watering, and decreased vision in the corneal features were severe in most cases compared with the affected eye(s). The duration of symptoms ranged from 1 day to 3 duration of symptoms. The corneal scraping smear, culture, and months. Eleven (57.8%) eyes were seen within 1 week of the onset sensitivity results are depicted in Table 3 (only significant growth of symptoms. Table 1 outlines various clinical details of the pa- is noted). tients. On as many as 11 occasions, bacilli were not seen in the Gram- A predisposing factor related to trauma could be identified in stained smears. Of these 11 eyes, two specimens revealed only five eyes. Some dust particle had fallen in the eyes of two children fungus, and one showed only Gram-positive cocci in smears. Of (1 and 12), and mud had fallen in the eye of another (4). The the remaining eight specimens, when bacilli were demonstrable, symptoms started after the eye was rubbed vigorously. One 8-year- Gram-positive rods were seen in only three. Three of the smears old child sustained injury to the eye with a metal rod (16), and showed Gram-variable bacilli (Fig. 3), and two showed Gram- another 18-year-old patient had trauma with a metal wire (6). In negative bacilli. The morphology of the bacilli, however, re- addition to these, seven eyes had some local predisposing factors. sembled that of typical Bacillus species (thick, beaded body, trun- Two eyes of the same patient (2 and 3) had lagophthalmos sec- cated ends, and often in chains). Spores (characteristic feature of

TABLE 1. Clinical features of patients with Bacillus keratitis

Duration of Visual acuity Size of Location of Final visual Eye no. Age/Sex Predisposing factor symptoms at presentation infiltrate (mm) infiltrate acuity 1 6M Dust fall 3 days 20/20 1 × 1 P 20/20 2 30M Lagophthalmos 3 mo 20/400 3 × 3 PC 20/30 3 30M Lagophthalmos 3 mo PL/PR 4.5 × 4 C PL/PR 4 3M Mud fall 10 days NA 11 × 11 T NA 5 22M Recurrent HSV keratitis 10 days 20/100 2 × 2 C 20/50 6 18M Metal wire injury 4 days 20/100 3.5 (Ring) PC 20/40 7 32M Old scar 1 wk No PL 3.2 × 3 C No PL 8 35M Old scar 1 day PL/PR 4 × 4 PC HM 9 30M Unknown 1 mo PL/PR 6 × 6 C PL/PR 10 65M Unknown 7 days PL/PR 11 × 11 T PL/PR 11 65M Unknown 2 mo PL/PR 7 × 6 C PL/PR 12 3F Dust fall 2 days NA 6 × 6 PC NA 13 36M Unknown 3 days 20/400 4 × 4 C 20/80 14 65M PBK 15 days PL/PR 4.5 × 4.5 C PL/PR 15 19F Unknown 4 days ?PL/PR 10 (Ring) C No PL 16 8M Metal rod injury 1 day PL/PR 3 × 3 P CF 17 70M ABK 2 days PL/PR Faint infiltrate PC CF 18 45M Unknown 15 days 20/70 1 × 1 PC 20/40 19 65F Diabetes 3 days HM 1 × 1 PC 20/30

P, peripheral; PC, paracentral; C, central; T, total; NA, not avilable; PBK, pseudophakic bullous keratopathy; ABK, aphakic bullous keratopathy; PL, perception of light; PR, projection of rays; HM, hand movement.

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TABLE 2. Extent of epithelial defects and stromal infiltrates in follow-up (Fig. 2). In two eyes of two children (3-year-olds), vi- eyes with Bacillus keratitis sual acuity could not be recorded. No. of cases Longest Epithelial defect Stromal infiltrate diameter (mm) (n = 19) (n = 18)a DISCUSSION 1–37 6 3–69 9 6–90 1Bacillus is not usually implicated as a pathogenic organism in >9 3 3 corneal ulcers. In the past, a few case reports have been pub- 2–4 5–8 a Eye no. 17 had only faint cellular infiltrates in the midstroma and lished. Some other reports included Bacillus species as an endothelial exudates. etiologic agent in occasional cases of microbial keratitis. Our own unpublished data show that Bacillus is identified as a causative organism in 1.4% of all bacterial keratitis. A recently published Bacillus species in culture) were not seen in any of the corneal- study from South India reports the incidence of Bacillus keratitis in scraping smears. Six eyes had polymicrobial keratitis, four of ∼2% of all bacterial corneal ulcers.9 Bacillus is known as an or- which were associated with other bacteria (eyes 2, 10, 12, and 16), ganism of high virulence, capable of causing serious ocular mor- and two had associated fungal infection (eyes 11, 13). Speciation bidity, especially in posttraumatic endophthalmitis.10 This is sup- of the Bacillus isolates was possible in 12 (63.1%) of 19 isolates. posedly due to the various toxins like phospholipases, proteases, Bacillus subtilis was the most common (three) followed by B. and hemolysins, which rapidly destroy the inner coats of the eye- megateriens (two), B. cereus (two), and B. polymyxa (two). Ba- ball. It is not clear whether the organism is equally destructive cillus coagulans, B. licheniformis, and B. firmus accounted for one while causing corneal ulcer. It is with this intent that this retro- case each. spective study was undertaken. Figure 4 summarizes the therapeutic strategy used in our pa- Our results show that this organism is capable of causing kera- tients and the results obtained. Ciprofloxacin (0.3%) eye drops titis in patients of all age groups. A male preponderance among the were used as monotherapy in eight eyes. Fortified cefazolin and affected population cannot be clearly explained. Bacillus is known fortified gentamicin were used together in five eyes, and chloram- to be commonly found in soil and is also particularly associated phenicol drops were used in two eyes. In four eyes, medical treat- with trauma due to contaminated metallic foreign body.1 The pre- ment needed to be altered. One eye with perforation (no. 3) un- disposing factors identified in our patients (dust particle, mud, derwent therapeutic PK with tarsorrhaphy as the primary proce- injury with wire and metal rod) should be added to those already dure. The graft subsequently failed. In six eyes that underwent known: contact lens wear.2 injury with vegetable matter4 or garden additional procedures, topical medications were still the mainstay tools,7 and exposure to biologic insecticide.5 In our series there of therapy. Two eyes (11 and 13) with mixed fungal infection were were two patients with bilateral simultaneous corneal ulcers treated with natamycin (5%) along with antibacterial antibiotics. caused by the same organism. One of them had leprosy with lag- Whereas eye 11 was lost to follow-up, eye 13 healed with a final ophthalmos in both eyes, which explains the bilateral disease. The visual acuity of 20/80 after 3 months. On the whole, the ulcers other patient, however, did not have any local or obvious systemic healed in 16 (84.2%) of 19 eyes. Three eyes (10, 11, and 15) of two predisposing factor, and his condition was particularly intriguing. patients were lost to follow-up. The time taken for the ulcers to A majority (87.5%) of the ulcers were central or paracentral in heal ranged from 1 to 120 days (mean, 37.4 ± 28.6 days; median, origin, and 68.42% had deep stromal involvement. When consid- 30 days). Posttreatment visual acuity was better than pretreatment ered together, these two findings indicate a potentially poorer vi- visual acuity in 10 (71.4%) of 14 eyes that were available for sual outcome. Corneal ring infiltrate has been described in the literature in the clinical setting of traumatic endophthalmitis caused by Bacillus species.10 Two of our patients had ring infiltrates. One (no. 6) did not have any evidence of endophthalmitis. The other (no. 15) had total corneal infiltrate with an inaccurate PR. She was treated presumptively as having endophthalmitis with systemic and topical antibiotics. However, a vitreous sampling was not done, and she was lost to follow-up after 4 days. Endophthalmitis was clinically suspected in two additional eyes (16 and 19). The first patient was an 8-year-old child who sustained injury to his eye with a metal rod 1 day before and was treated elsewhere with ciprofloxacin (0.3%) and gentamicin (0.3%) drops every 3 h before being referred to our center. His visual acuity was light perception with accurate projection of rays, and he had a 3-mm peripheral deep corneal infiltrate in an area of sealed penetrating corneal injury (Fig. 1). The anterior chamber was full of exudates (Fig. 1). Scrapings from the ulcer revealed FIG. 1. Slit-lamp photograph under diffuse illumination showing pe- gram- positive cocci and gram-variable bacilli (Fig. 3) in smears, ripheral deep corneal infiltrate in an area of sealed penetrating cor- and cultures grew significant Staphylococcus epidermidis and B. neal injury in an 8-year-old child (eye no. 16). cereus. Vitreous biopsy did not show any organism on Gram stain

Cornea, Vol. 19, No. 3, 2000 304 K.K. CHOUDHURI ET AL.

FIG. 2. Visual acuity of patients with Bacillus keratitis before and after treatment. and did not grow any organism subsequently. He was treated with tion of the infiltrate and clearing of exudates from the anterior intravitreal vancomycin (1 mg) and gentamicin (200 ␮g) and topi- chamber (Fig. 5) and healed with a scar and cataract at 1 month cal fortified gentamicin/cefazolin drops along with systemic cefa- with a final visual acuity of counting fingers. zolin and gentamicin. He showed rapid improvement with resolu- The other patient with suspected endophthalmitis was a 65-year-

TABLE 3. Laboratory findings of the corneal scrapings from 19 eyes with Bacillus keratitis

Antibiotic susceptibility results Eye no. Gram stain Culture results CH CZ G CIP NOR 1. Gm+ bacilli B. polymyxa SSSS S 2. Gm− bacilli Bacillis spp. R R S S S Micrococcus spp. ND ND ND ND ND 3. Gm− bacilli Bacillus spp. R R S S S 4. No organisms B. subtilis RRS S S 5. No organisms B. firmus SSSS S 6. Gm-variable, bacilli B. cereus SSSS S 7. No organisms B. megateriens SSSS S 8. No organisms Bacillus spp. ND ND ND ND ND 9. Gm-variable, bacilli B. licheniformis SSSS S 10. No organisms B. subtilis SSSS S P. aeruginosa IRSSS 11. Fungal filaments B. subtilis SSSS S P. aeruginosa IRSSS Bipolaris spp. ND ND ND ND ND 12. No organisms Bacillus spp. S R S R R S. epidermidis IRRRR 13. Fungal filaments Bacillus spp. S S S S S UIH fungus ND ND ND ND ND 14. Gm+ bacilli B. megateriens SSSS S 15. Gm+ bacilli B. polymyxa SRSS S 16. Gm+ cocci B. cereus SI SS S Gm-variable bacilli S. epidermidis SSSS S 17. No organisms Bacillus spp. S R S S S 18. No organisms Bacillus spp. S S S S S 19. Gm+ cocci B. coagulans SSSS S

UIH, unidentified hyaline; ND, not done; R, resistant; I, intermediate; S, sensitive; CH, chloramphenicol; CZ, cefazolin; G, gentamicin; CIP, ciprofloxacin; NOR, norfloxacin.

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FIG. 3. Gram-stained corneal scraping of eye no. 16 showing gram- FIG. 5. Slit-lamp optical section of eye no. 16 showing resolution of positive thick bacilli along with gram-negative bacilli (gram-variable) the anterior chamber exudates within 3 days of intensive topical and of similar morphology (original magnification ×1,250). intravitreal therapy. old diabetic woman (no. 19) who had sudden painful loss of vision cillus keratitis. Apart from the two eyes of a patient with bilateral in one eye of 3 days’ duration. Visual acuity was hand movement, polymicrobial keratitis (nos. 10 and 11) and another (no. 15) for and she had a 1-mm paracentral infiltrate along with vitreous exu- whom there was no follow-up, the infection could be controlled in dates. Scrapings from the ulcer showed gram-positive cocci in all instances. The overall prognosis in this condition thus appears pairs but subsequently showed significant growth of B. coagulans to be reasonably good. alone. Pars plana vitrectomy was done. Vitreous sample showed Gram-stain smear results were not very encouraging in this gram-positive cocci in smears but did not grow any organism. She study, as only on three occasions were definite gram-positive ba- was treated with topical fortified gentamicin and cefazolin drops cilli resembling Bacillus species seen; however, a notable finding along with oral ciprofloxacin, 750 mg twice daily, and intravitreal was presence of gram-variable bacilli in three smears (Fig. 3). vancomycin (1 mg) and amikacin (400 ␮g). She healed with a scar Bacillus species are known to have variable staining patterns;11 after 4 months, and her final best corrected visual acuity was therefore, presence of gram-variable or gram-negative bacilli with 20/30. morphology similar to Bacillus should raise a suspicion for this Analysis of the in vitro susceptibility test showed that all 16 group of organisms. A high level of suspicion would lead to rec- isolates tested were sensitive to gentamicin, and 15 were suscep- ognition of more cases. The organisms are not difficult to grow; tible to both ciprofloxacin and norfloxacin. Fourteen isolates were therefore, a careful correlation of clinical and microbiologic find- sensitive to chloramphenicol. When tested against cefazolin, 10 ings would help to determine the diagnosis and effectively treat isolates were sensitive, and one showed intermediate sensitivity. this condition in most cases. Among the 15 eyes that healed without therapeutic PK, ciprofloxa- In conclusion, as per the Medline search, we described one of cin was used as monotherapy in eight eyes, a cefazolin/gentamicin the largest series of Bacillus keratitis. Bacillus should always be combination was used in five eyes, and chloramphenicol drops considered in the differential diagnosis when there is a history of were used for two eyes. Exhibiting a good measure of activity, a injury to eye after dust falling in the eye, or trauma with a metallic combination of cefazolin and gentamicin or a fluoroquinolone foreign body. Eyes with preexisting local predisposing factors such alone appears to be efficacious as first-line treatment against Ba- as lagophthalmos, old scar, or bullous keratopathy also are likely

FIG. 4. Therapeutic strategy and outcome in patients with Bacillus keratitis.

Cornea, Vol. 19, No. 3, 2000 306 K.K. CHOUDHURI ET AL. to be infected with Bacillus species. The keratitis is usually central 4. Tabbara KF, Tarabay N. Bacillus licheniformis corneal ulcer. Am J or paracentral and varies in severity, which is often disproportion- Ophthalmol 1979;87:717–9. ate to the duration of symptoms. The organisms are usually sus- 5. Samples JR, Buettner H. Ocular infections caused by a biological ceptible to commonly used antibacterial agents, and the ulcers heal insecticide. J Infect Dis 1983;148:614. satisfactorily with medical therapy. 6. Horsburgh BJ, Stark DJ, Harrison JD. Ocular injuries caused by mag- pies. MedJAust1992;157:756–9. Acknowledgment: Financial support was given by Hyderabad Eye Re- 7. Clinch TE, Palmon FE, Robinson MJ, Cohen EJ, Barron BA, Laibson search Foundation, Hyderabad, India. PR. Microbial keratitis in children. Am J Ophthalmol 1994;117:65–71. 8. Ormerod LD, Smith RE. Contact lens associated microbial keratitis. Arch Ophthalmol 1986;104:79–83. REFERENCES 9. Srinivasan M, Gonzales CA, George C, et al. Epidemiology and ae- tiological diagnosis of corneal ulceration in Madurai, South India. Br 1. Affeldt JC, Flynn HW, Forster RK, Mandelbaum S, Clarkson JG, Jarus J Ophthalmol 1997;81:965–71. GD. Microbial endophthalmitis resulting from ocular trauma. Ophthal- mology 1987;94:407–13. 10. O’Day DM, Smith RS, Gregg CR, et al. The problem of Bacillus 2. Donzis PB, Mondino BJ, Weissman BA. Bacillus keratitis associated species infection with special emphasis on the virulence of Bacillus with contaminated contact lens care systems. Am J Ophthalmol 1988; cereus. Ophthalmology 1981;88:833–8. 105:195–7. 11. Turnbull PCB, Kramer JM. Chapter 28. Bacillus. In: Murray PR, ed. 3. Van Bijsterveld OP, Richards RD. Bacillus infections of the cornea. Manual of clinical microbiology. 6th ed. Washington, DC; ASM Press, Arch Ophthalmol 1965;74:91. 1995:349.

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