Journal List > J Korean Ophthalmol Soc > v.51(12) > 1008701

Kim and Lee: Analysis on Elderly Inpatients with Infectious Keratitis: Causative Organisms, Clinical Aspects, and Risk Factors

Abstract

Purpose

To investigate the difference of the epidemiological, microbiological, and clinical characteristics and risk factors of inpatients with infectious keratitis between an elderly group (group I ≥ 60 years) and a younger group (group II < 60 years).

Methods

A retrospective chart review of 255 eyes (male/female: 158/97 eyes, I/II: 116/139 eyes) with infectious keratitis hospitalized at Yeungnam University Hospital between January 2004 and December 2008 was performed.

Results

The proportion of bacterial/fungal/herpes viral keratitis was 42/31/27% in group I and 74/8/17% in group II. The proportion of fungal keratitis in relation to bacterial keratitis was higher in group I, as compared to group II (p < 0.001). The ratio of Gram-positive/negative bacteria was 43/30% in group I and 48/46% in group II. The proportion of Gram-positive bacteria in relation to Gram-negative bacteria was higher in group I, as compared to group II (p = 0.025). The most commonly isolated microorganisms were Staphylococcus epidermidis (I/II: 9/10 eyes) among Gram-positive bacteria, Enterobacter species (I: 6 eyes) and Pseudomonas aeruginosa (II: 9 eyes) among Gram-negative bacteria, and Candida species (I: 6 eyes, II: 2 eyes) among fungi. Clinical aspects and treatment outcomes, such as previous ocular surgery (I/II: 23/9%), hypertension (26/7%), diabetes mellitus (17/7%), presentation at our clinic after 1 week (43/16%), initial visual acuity less than 0.1 (54/32%), hypopyon (28/15%), epithelial healing time (16/10 days), corneal perforation (18/5%), operative treatment (23/7%), and final visual acuity less than 0.1 (36/14%) were statistically significantly poorer in group I, as compared to group II. Risk factors for unimproved visual outcomes included fungal keratitis in group I and previous ocular surgery and ocular surface disease in group II.

Conclusions

Considering that clinical aspects and treatment outcomes are poor in elderly inpatients with infectious keratitis, special efforts are necessary for a more accurate differential diagnosis and appropriate early treatment to achieve successful treatment outcomes.

References

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Table 1.
Patient demographics according to study groups
Group Ⅰ≥ 60 years Group Ⅱ< 60 years
No. of eyes 116 139
Mean age ± SD (yr) 69.0 ± 6.1 39.5 ± 15.3
Sex ratio (male/female) 1.58 (71/45) 1.67 (87/52)
Table 2.
Incidence and positive culture rates of infectious keratitis
Culture No. of cases (%)
GroupⅠ≥ 60 years (N = 116)
GroupⅡ< 60 years (N = 139)
Bacteria Fungus [KOH +/-] Herpes Bacteria Fungus [KOH +/-] Herpes Amoeba
Positive 25 10* [7/3] 41 2 [1/1] 1
Negative 24 26 [10/16] 31 62 9 [2/7] 24
Total 49 (42.3) 36 (31.0) 31 (26.7) 103 (74.1) 11 (7.9) 24 (17.3) 1 (0.7)

* Two eyes had mixed fungal and bacterial infections (mixed Candida tropicalis and S. pneumoniae, mixed Fusarium species and E. faecalis)

Two eyes had mixed bacterial and bacterial infections (mixed Serratia marscens and P. aeruginosa, mixed S. epidermidis and S. pneumoniae)

Two eyes had mixed fungal and bacterial infections (mixed Candida albicans and S. pneumoniae, mixed Candida albicans and S. epidermidis).

Table 3.
Cultured microorganisms of infectious keratitis
Organisms No. of isolates (%)
GroupⅠ≥ 60 years (N = 37) GroupⅡ< 60 years (N = 48)
N Subtotal Total N Subtotal Total
Bacteria 27 (73.0) 45 (93.7)
Gram (+) cocci 16 (43.2) 23 (47.9)
Staphylococcus species
Coagulase () S. epidermidis 9 10
S. haemolyticus 1
Coagulase (+) S. aureus 1 4
Streptococcus species
S. pneumoniae 4 3
Enterococcus species
E. faecalis 2 5
Gram () rods 11 (29.8) 22 (45.8)
Enterobacter species
E. aerogens 4 3
E. cloacae 2 2
Pseudomonas species
P. aeruginosa 3 9
Morganella morganii 1 1
Delftia 1
Serratia species
S. marscens 4
S. liquefaciens 1
Klebsiella species
K. pnuemoniae 1
E.coli 1
Fungus 10 (27.0) 2 (4.2)
Yeasts 6 (16.2) 2 (4.2)
Candida species
C. albicans 4 2
C. tropicalis 2
Filamentous fungi 4 (10.8)
Aspergillus species 2
Fusarium species 1
Syncephalastrum 1
Acanthamoeba A. castellani 1 (2.1)
Table 4.
Age and sex distributions of patients with infectious keratitis
Age No. of cases (%)
GroupⅠ≥ 60 years
GroupⅡ< 60 years
Bacteria (N = 29)
Fungus (N = 36)
Herpes (N = 31)
Total (N = 116)
Age Bacteria (N = 103)
Fungus (N = 11)
Herpes (N = 24)
Total (N = 139)
M* F M F M F M F M F M F M F M F
60–69 22 8 10 9 10 8 42 (36.2) 25 (21.5) 0–9 3 1 3 (2.2) 1 (0.7)
70–79 8 9 11 3 5 5 24 (20.7) 17 (14.7) 10–19 7 3 3 1 10 (7.2) 5 (3.6)
80–89 2 2 1 1 2 5 (4.3) 3 (2.6) 20–29 6 16 1 1 1 7 (5.0) 18 (12.9)
30–39 11 5 1 11 (7.9) 6 (4.3)
40–49 15 5 2 1 4 2 21 (15.1) 8 (5.8)
50–59 21 11 6 1 8 2 35 (25.2) 14 (10.1)
Total 32(27.6) 17(14.7) 23(19.8) 13(11.2) 16(13.8) 15(12.9) 71(61.2) 45(38.8) Total 63(45.3) 40(28.8) 8(5.8) 3(2.2) 16(11.5) 8(5.8) 87(62.6) 52(37.4)

* M = Male

F = Female

One case (0.7%) of acanthamoeba infection is included in 5 cases.

Table 5.
Occupation of patients with infectious keratitis
Occupation No. of cases (%)
GroupⅠ≥ 60 years
GroupⅡ< 60 years
Bacteria Fungus Herpes Total Bacteria Fungus Herpes Total
(n = 49) (n = 36) (n = 31) (n = 116) (n = 103) (n = 11) (n = 24) (n = 139)
Farmer 27 25 10 62 (53.4) 22 8 3 33 (23.7)
Housewife 13 4 5 22 (19.0) 9 1 2 12 (8.6)
Unemployed 4 4 12 20 (17.2) 1 3 4 (2.9)
Laborer 3 2 5 (4.3) 23 3 26 (18.7)
Office worker 2 1 3 (2.6) 24 1 5 30 (21.6)
Unknown 2 2 4 (3.5) 1 2 3 (2.2)
Student 23 1 6 31*(22.3)

* One case (0.7%) of acanthamoeba infection is included in 31 cases.

Table 6.
Identified predisposing factors in patients with infectious keratitis
Predisposing factor No. of cases*
GroupⅠ≥ 60 years (N = 116)
GroupⅡ< 60 years (N = 139)
Bacteria (N = 49) Fungus (N = 36) Herpes (N = 31) Total Bacteria (N = 103) Fungus (N = 11) Herpes (N = 24) Total
Trauma vector Vegetable 23 24 47 25 7 32
Grass 10 14 24 9 3 12
Tree 11 8  19 12 4 16
Thorn 2 2  4 4 4
Soil, Stone 8 3 1 12 8 2 10
Finger 6 1 1 8 7 7
Water 3 3 6 7 1 1 9
Metal 2 2 14 14
Unknown 4 1 5 3 1 4
Contact lens 24 1 2 28
Previous ocular surface disease and surgery Herpetic keratitis 6 6 3 3
Bullous keratopathy 3 1 1 5 2 2
PED 2 1 3 2 2
RES§ 1 1 2 1 1 2
Trichiasis 1 1 2 1 1
Atopic conjunctivitis 1 1 1 1
Phlyctenular keratitis 1 1 1 1
POS 14 2 11 27 9 4 13
Systemic disease Hypertension 13 8 9 30 8 2 10
Diabetes mellitus 8 5 7 20 7 3 10
CVA# 2 3 5
Asthma 2 1 3
Heart problem 2 2 1 1
Rheumatic disease 2 2 2 2
Hepatitis B or C 1 1 2 1 1
Gout 1 1
Thyroid disease 1 1 1 1
Colon cancer 1 1
Atopic dermatitis 1 1
Budd-chiari SD 1 1

* Number of eyes which has been identified for predisposing factors such as trauma vector, previous ocular surface disease or surgery, and systemic disease before the time of presentation (Sum of the number of eyes with each subgroup does not add up to 100% because of no history of identified predisposing factors)

One case of acanthamoeba infection is included in 28 cases

PED = Persistent epithelial defect

§ RES = Recurrent erosion syndrome

POS = Previous ocular surgery

# CVA = Cerebrovascular disease.

Table 7.
Characteristics of symptom duration and used topical medications prior to patient presentation to our clinic
Characteristic No. of cases (%)
GroupⅠ≥ 60 years
GroupⅡ< 60 years
Bacteria Fungus Herpes Total Bacteria Fungus Herpes Total
Period* ≤ 1 week 36 14 16 66 (56.9) 94 6 17 117 (84.2)
> 1 week 13 22 15 50 (43.1) 9 5 7 22 (15.8)
N 49 36 31 116 (100) 103 11 24 139 (100)
Topical medication Antibiotics 24 14 8 46 51 4 9 64
Antifungals 1 1 2 1 1 2
Antivirals 1 2 3 6 6
Steroids 11 9 2 22 13 1 3 17
N§ 25 24 11 60 54 5 14 73

* Days between symptom onset and patient presentation at our clinic

One case (0.7%) of acanthamoeba infection is included in 22 cases

Ocular topical medications used prior to clinical presentation at our clinic

§ N = Number of eyes which has been identified for the use of topical medication and topical antibiotics by patients before, or at the time of presentation (Sum of the number of eyes with each subgroup does not add up to 100% because of overlap of subgroups).

Table 8.
Clinical characteristics of infectious keratitis at initial presentation
Corneal lesion No. of cases (%)
GroupⅠ≥ 60 years
GroupⅡ*< 60 years
Bacteria Fungus Herpes Total Bacteria Fungus Herpes Total
(N = 49) (N = 36) (N = 31) (N = 116) (N = 103) (N = 11) (N = 24) (N = 139)
Location Central 22 18 14 54 (46.5) 45 6 10 61 (43.9)
Paracentral 19 14 13 46 (39.7) 45 5 8 59 (42.4)
Marginal§ 8 4 4 16 (13.8) 12 6 18 (13.0)
Total 1 1 (0.7)
Size < 3 mm 30 19 13 62 (53.4) 80 8 13 102 (73.4)
≥ 3 mm 19 17 18 54 (46.6) 23 3 11 37 (26.6)
Hypopyon Yes 10 14 8 32 (27.6) 16 4 1 21 (15.1)
No 39 22 23 84 (72.4) 87 7 23 118 (84.9)

* One case of acanthamoeba infection is not presented in groupⅡ(paracentral location, less than 3 mm size & no hypopyon)

Corneal lesion is located within 2 mm radius from the center of the cornea

Corneal lesion is between central and marginal cornea

§ Corneal lesion is located within 2 mm from the limbus

Corneal lesion involved nearly total cornea.

Table 11.
Methods of therapy in infectious keratitis
Treatment No. of cases (%)
GroupⅠ≥ 60 years
GroupⅡ< 60 years
Bacteria Fungus Herpes Total Bacteria Fungus Herpes Total
(N = 49) (N = 36) (N = 31) (N = 116) (N = 103) (N = 11) (N = 24) (N = 139)
Medical treatment 41 23 25 89 (76.7) 96 10 22 129*(92.8)
AMT 7 4 6 17 (14.7) 6 1 2 9 (6.5)
Conjunctival flap 5 5 (4.3) 1 1 (0.7)
Evisceration 1 4 5 (4.3)

* One case (0.7%) of acanthamoeba infection is included in 129 cases

AMT = Amniotic membrane transplantation.

Table 12.
Risk factors for unimproved visual outcome in infectious keratitis (univariate analysis)
Factor GroupⅠ≥ 60 years
GroupⅡ< 60 years
No. of pts. (%)* OR 95% CI p-value No. of pts. (%) OR 95% CI p-value
Gender
Female 13/45 (28.9) 1.00 9/52 (17.3) 1.00
Male 26/71 (36.6) 1.42 0.64∼3.18 0.395 17/87 (19.5) 1.16 0.48∼2.83 0.746
Previous ocular surface disease
No or unknown 28/96 (29.2) 1.00 19/127 (15.0) 1.00
Yes 11/20 (55.0) 2.97 1.11∼7.95 0.026 7/12 (58.3) 7.96 2.29∼27.69 0.001
Previous ocular surgery
No or unknown 27/89 (30.3) 1.00 20/126 (15.9) 1.00
Yes 12/27 (44.4) 1.84 0.76∼4.44 0.177 6/13 (46.2) 4.54 1.38∼14.94 0.007
Systemic disease
No or unknown 21/65 (32.3) 1.00 19/117 (16.2) 1.00
Yes 18/51 (35.3) 1.14 0.53∼2.48 0.738 7/22 (31.8) 2.41 0.87∼6.69 0.087#
Ocular trauma history
No or unknown 13/36 (36.1) 1.00 9/35 (25.7) 1.00
Yes 26/80 (32.5) 0.85 0.37∼1.95 0.706 17/104 (16.3) 0.56 0.23∼1.42 0.222
Use of steroid eyedrops
No or unknown 33/94 (35.1) 1.00 25/122 (20.5) 1.00
Yes 6/22 (27.3) 0.69 0.25∼1.94 0.488 1/17 (5.9) 0.24 0.03∼1.92 0.150
Symptom duration
≤ 1 week 21/66 (31.8) 1.00 20/117 (17.1) 1.00
> 1 week 18/50 (36.0) 1.21 0.56∼2.62 0.640 6/22 (27.3) 1.82 0.63∼5.22 0.265
Location
Others 16/62 (25.8) 1.00 8/78 (10.3) 1.00
Central 23/54 (42.6) 2.13 0.97∼4.67 0.057# 18/61 (29.5) 3.66 1.47∼9.15 0.004
Size
< 3 mm 15/62 (24.2) 1.00 16/102 (15.7) 1.00
≥ 3 mm 24/54 (44.4) 2.51 1.14∼5.53 0.021 10/37 (27.0) 1.99 0.81∼4.90 0.132
Hypopyon
No 25/84 (29.8) 1.00 17/118 (14.4) 1.00
Yes 14/32 (43.8) 1.84 0.79∼4.25 0.157 9/21 (42.9) 4.46 1.63∼12.18 0.002
Epithelial healing time
≤ 10 days 8/42 (19.0) 1.00 13/98 (13.3) 1.00
> 10 days 31/74 (41.9) 3.04 1.25∼7.52 0.012 13/41 (31.7) 3.04 1.26∼7.32 0.011
Initial BCVA§
≥ 0.1 13/54 (24.1) 1.00 10/94 (10.6) 1.00
< 0.1 26/62 (41.9) 2.28 1.02∼5.08 0.043 16/45 (35.6) 4.63 1.89∼11.35 0.001
Culture
Negative 29/81 (35.8) 1.00 16/95 (16.8) 1.00
Positive 10/35 (28.6) 0.72 0.30∼1.70 0.454 10/44 (22.7) 1.45 0.60∼3.52 0.412
Organisms
Others 21/80 (26.3) 1.00 24/128 (18.8) 1.00
Fungi 18/36 (50.0) 2.81 1.24∼6.39 0.012 2/11 (18.2) 0.96 0.20∼4.75 0.963

* (%) = Percentage of eyes which had unimproved visual outcome

OR = Odds ratio

CI = Confidence interval

§ BCVA = Best corrected visual acuity

p<0.05

# p<0.1.

Table 13.
Risk factors for unimproved visual outcome in infectious keratitis (multivariate analysis)
Factor GroupⅠ≥ 60 years
Factor GroupⅡ< 60 years
OR* 95% CI p-value OR 95% CI p-value
Previous ocular surface disease 2.74 0.96∼5.76 0.074 Previous ocular surface disease 4.66 1.97∼9.74 0.040§
Initial BCVA less than 0.1 1.26 0.61∼2.54 0.631 Initial BCVA less than 0.1 1.98 0.94∼4.12 0.240
Epithelial healing time more than 10 days 2.01 0.84∼4.26 0.172 Epithelial healing time more than 10 days 2.24 0.96∼4.51 0.146
Central location 1.57 0.76∼3.41 0.321 Central location 2.29 0.97∼4.53 0.137
Size more than 3 mm 1.66 0.78∼3.58 0.275 Systemic disease 1.32 0.61∼2.72 0.662
Fungal keratitis 2.86 1.23∼6.11 0.023§ Previous ocular surgery 4.80 2.01∼9.98 0.032§
Hypopyon 1.89 0.91∼4.21 0.316

* OR = Odds ratio

CI = Confidence interval

BCVA = Best corrected visual acuity

§ p<0.05.

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