**11. Gram negative bacteria**

**Figure 14.** *Nocardia asteroides* cultures from cornea sample of patient in figure 12.

(Figure 16), and the cultures grows visible colonies in 7 days. (Figure 17)

**Figure 15.** Post-penetrate keratoplasty contaminated with *Mycobacterium chelonae*

1000 X (Left).

72 Common Eye Infections

**Non tuberculous Mycobacterium:***Mycobacterium chelonae, M intracelulare* are rapidly growing bacteria (7 to 8 days) and are related to low pain or indolent keratitis with torpid evolution, diffi‐ culty in diagnosis and with poor results in the treatment. The risky antecedent are corneal ero‐ sions or cornea transplant (Figure 15). The topical treatment needs long time and various antibiotics; fourth generation quinolones, amikacyn and clarytromycin. In the smears often it is observed Gram irregular and curved bacilli that in Zihel-Neelsen stain appear in a reddish color

**Figure 16.** Corneal smear Zihel-Neelsen stained, showing acid-fast bacilli (black arrow) of the patient in figure 12

**Pseudomonas aeruginosa:** Keratitis caused by *Pseudomonas* that are initiated by the prolonged use of contaminated contact lens, or by traumatic erosion over the corneal epithelium, rapidly progress into cornea stroma and edema in clear cornea zones (Figure 18), these ulcers are pain‐ ful, and without early antibiotic treatment can progress to endophtalmitis and in some rare cas‐ es to severe panophthalmia and vision loss. In the Gram stain of the smear it is observed red small rods (Figure 19), in blood agar white-gray mucous colonies are developed in 18 to 24 hours surrounded by beta hemolytic zone and greenish fluorescein pigment (Figure 20).

**Figure 18.** *Pseudomonas,* post-trauma keratitis with hypopyon and corneal vessels in unresponsive case to topic anti‐ biotic treatment.

**Figure 19.** Gram negative rods, (black arrow) in the smear from corneal ulcer from patient in figure 15. 1000 X.

**Capnocytophagasputigena.***Capnocytophaga* is a rare keratitis cause, it was described in immu‐ no suppressed patients as risk factor but it was also found in normal young adult patients, (Fig‐ ure 21). *Capnocytophaga* is normal flora in human and animal (dogs) mouth and the cornea contamination can be by its own patient saliva, in contact lens wearers that use saliva for hu‐ mectation before putting on his contact lens. In Gram stain smears it appears like negative long rod, (Figure 22) it is a bacterium that grows in 5 to 10% CO2 environment and move away from the site of seed because it is *flagellae* as is showed in cultures. (Figure 23)

**Figure 21.** Paracentral, temporal inferior corneal ulceration, caused by *Capnocytophaga sputigena* in a young adult male.

**Figure 23.** C strikes seeds of *Capnocytophaga sputigena* obtained in the corneal sample culture from patient in figure 21.

**Moraxella lacunata.** Keratitis related to *Moraxella lacunata* or other *Moraxella* species are ob‐ served in patients ofany age, in some cases,the authors [19] describe some immunodeficien‐ cy in elderly or malnourished people. Keratitis appear like an abscess or like non severe keratitis, with chronic evolution (Figure 24), in the smears Gram and Giemsa stained appear like broad rods (Figure 25) and in culture the colonies are small and translucent (Figure 26), *Moraxella* is a non fermentative bacteria.

**Figure 24.** Corneal abscesses in an adult female caused by *Moraxella lacunata.*

**Figure 20.** Gray mucous colonies of *Pseudomonas aeruginosa* surrounded by greenish hemolytic zone of fluorescein

**Capnocytophagasputigena.***Capnocytophaga* is a rare keratitis cause, it was described in immu‐ no suppressed patients as risk factor but it was also found in normal young adult patients, (Fig‐ ure 21). *Capnocytophaga* is normal flora in human and animal (dogs) mouth and the cornea contamination can be by its own patient saliva, in contact lens wearers that use saliva for hu‐ mectation before putting on his contact lens. In Gram stain smears it appears like negative long rod, (Figure 22) it is a bacterium that grows in 5 to 10% CO2 environment and move away from

**Figure 21.** Paracentral, temporal inferior corneal ulceration, caused by *Capnocytophaga sputigena* in a young adult

**Figure 22.** Long and folded Gram negative rod of *Capnocytophaga sputigena* (black arrow) in the secretion keratitis

the site of seed because it is *flagellae* as is showed in cultures. (Figure 23)

pigment.

74 Common Eye Infections

male.

from patient in figure 21

**Figure 25.** Gram negative broad rods *Moraxella*, from a cornea scraping smear Gram stained. 1000 X.

**Figure 26.** White-yellow colonies, in the C strikes from cornea samples and conjunctiva samples.

**Neisseria gonorrhoae, N meningitidis**. Keratitis related to *Neisseria* conjunctivitis or menin‐ gitis is always severe and painful, it appears in newborns and in young adults involved in sexual activities. The conjunctiva with unilateral presentation is often observed with a very important edema (chemosis) and for this reason, the patient can no open the eye, after the oral or intravenous administration of adequate antibiotic from betalactamic group, the con‐ junctiva return to normality and the ophthalmologist can explore searching corneal deep ul‐ cers (Figure 27). An early laboratory diagnostic is mandatory by Gram stain on the abundant conjunctiva secretion, always is observed intracellular Gram negative diplococcic in polymorphonuclear leukocytes (Figure 28), in cultures in agar chocolate and CO2 ambient colonies are small, gray-translucent, oxidase test positive, and by sugar fermentation, semi automated, automated test or latex coaglutination can be specie recognized, and tested for betalactamic antibiotic susceptibility (figure 29).

**Figure 27.** Deep cornea ulceration near the *limbus*, in a male young adult in a case of *Neisseria gonorrhoae* kerato conjunctivitis.

#### **12. Fungal keratitis**

Mainly ocular trauma, surgical trauma like corneal transplantation (PKP), Laser in situ kera‐ tomieleusis (LASIK) or Photorefractive keratectomy (PRK), use of contaminated contact lens and dry eye originated from tears alterations are the most common precipitating events for fungal keratitis, some of them are caused by opportunistic white filamentous,melanized, or yeast like fungus. Early diagnosis and treatment of these chronic and torpid in clinical evo‐ lution infections are important, to achieve a better visual acuity.

**Figure 28.** Intracellular in polymorphonuclear leukocyte, Gram negative diplococci observed in conjunctiva secretion in patient from Figure 24 1000X

**Figure 29.** Antibiogram in Mueller-Hinton Blood agar by diffusion disk method (Kirby and Bauer) of Neisseria gonor‐ *rhoeae*

Some of opportunistic fungus are normal flora in the mouth mucous like Candida, others arrive to conjunctiva in the spores forms and do not cause any harmful to conjunctiva or cor‐ nea because the normal blink and tear film wash them away [20], the risky factor mentioned above can cause the entrance of the fungi living cells to deep cornea and originate edema and other chronic keratitis with severe clinical manifestations even the ocular loss.

White filamentous Fungi.

**Figure 26.** White-yellow colonies, in the C strikes from cornea samples and conjunctiva samples.

betalactamic antibiotic susceptibility (figure 29).

conjunctivitis.

76 Common Eye Infections

**12. Fungal keratitis**

**Neisseria gonorrhoae, N meningitidis**. Keratitis related to *Neisseria* conjunctivitis or menin‐ gitis is always severe and painful, it appears in newborns and in young adults involved in sexual activities. The conjunctiva with unilateral presentation is often observed with a very important edema (chemosis) and for this reason, the patient can no open the eye, after the oral or intravenous administration of adequate antibiotic from betalactamic group, the con‐ junctiva return to normality and the ophthalmologist can explore searching corneal deep ul‐ cers (Figure 27). An early laboratory diagnostic is mandatory by Gram stain on the abundant conjunctiva secretion, always is observed intracellular Gram negative diplococcic in polymorphonuclear leukocytes (Figure 28), in cultures in agar chocolate and CO2 ambient colonies are small, gray-translucent, oxidase test positive, and by sugar fermentation, semi automated, automated test or latex coaglutination can be specie recognized, and tested for

**Figure 27.** Deep cornea ulceration near the *limbus*, in a male young adult in a case of *Neisseria gonorrhoae* kerato

Mainly ocular trauma, surgical trauma like corneal transplantation (PKP), Laser in situ kera‐ tomieleusis (LASIK) or Photorefractive keratectomy (PRK), use of contaminated contact lens and dry eye originated from tears alterations are the most common precipitating events for fungal keratitis, some of them are caused by opportunistic white filamentous,melanized, or

**Fusarium:***Fusarium solani* are the most frequent cause of keratitis in the series published [21]. In México, 37.2 % fungal keratitis is caused by *F solani, F dimerum, F oxysoporum*, trauma was referred in 35.5 % cases. 75% of cases were observed in males, 38.1% with agricultural activi‐ ties referred as risk factor, and only 25% in females. In 18 % cases were observed at slit lamp satellite lesions [22], (Figure 30) and 6 % progressed to inflammatory or fungal endophthal‐ mitis, this complication is not frequent in the course of keratitis. [23, 24]

In the laboratory, the diagnosis is made in the scraped sample from the cornea infiltrate as above referred, stained with PAS (Figure 31) or, calcofluor-Evans Blue (Cellfluor) and epi‐ fluorescent light microscopy. In the cultures *Fusarium* grows fast, cottony white colonies ap‐ pear at 48 or 72 hours in Sabouraud-Emmons at 37o C incubation (Figure 32) [23]. In microcultures for identification, round or piriform microconidia and long-curved macroco‐ nidia 3 to 4 cells are characteristic for specie identification.

**Figure 30.** Satellite lesions, hypopyon in anterior and posterior chamber in a *Fusarium* keratitis in 45 year-old male.

**Figure 31.** Septate hyphae in corneal scraping smear stained with PAS 1000 X

**Figure 32.** *Fusarium solani* culture from Figure 30 patient

**Aspergillus** In keratomycose cases *Aspergillus fumigatus, A. nidulans A. flavus, A. niger,* and other species are often isolated, corneal infections are severe and with a poor response to an‐ tifungal treatment because *Aspergillus* are intrinsically resistant, in Mexico 10.6 % of fungal keratitis was caused by *Aspergillus* in a serial study including 219 cases; 26% patients in‐ volved in agricultural activities, 78.6% males and 21.4 females, 26% cases were eviscerated with the ocular loss (Figure 33) [25].

In Sabouraud-Emmons without cicloeximide media growth white greenish-blue or black *Aspergillus niger* colonies in 3 to 4 incubation 27o C days or in blood agar plates (Figure 34), and in microcultures and cotton blue stain shows the characteristic collumela and conidiophores with phialides uniseriate or biseriate with round or oval conidia growing over them (Figure 35).

pear at 48 or 72 hours in Sabouraud-Emmons at 37o

78 Common Eye Infections

nidia 3 to 4 cells are characteristic for specie identification.

**Figure 31.** Septate hyphae in corneal scraping smear stained with PAS 1000 X

**Figure 32.** *Fusarium solani* culture from Figure 30 patient

with the ocular loss (Figure 33) [25].

microcultures for identification, round or piriform microconidia and long-curved macroco‐

**Figure 30.** Satellite lesions, hypopyon in anterior and posterior chamber in a *Fusarium* keratitis in 45 year-old male.

**Aspergillus** In keratomycose cases *Aspergillus fumigatus, A. nidulans A. flavus, A. niger,* and other species are often isolated, corneal infections are severe and with a poor response to an‐ tifungal treatment because *Aspergillus* are intrinsically resistant, in Mexico 10.6 % of fungal keratitis was caused by *Aspergillus* in a serial study including 219 cases; 26% patients in‐ volved in agricultural activities, 78.6% males and 21.4 females, 26% cases were eviscerated

C incubation (Figure 32) [23]. In

**Figure 33.** *Aspergillus flavus* keratitis, three weeks after trauma contaminated with organic soil material.

**Figure 34.** *Aspergillus nidulans* colony from keratomycose patient in Figure 33

**Figure 35.** *Aspergillus niger* conidial head, uniseriate phialides and round conidia in lactophenol blue direct micro‐ scopic observation from microcultures.

**Filamentous Melanized fungus.** Many species of opportunistic filamentous melanized (for‐ merly Dematiaceous) fungus related to keratomycoses have been described. *Curvularia, Al‐ ternaria, Phialophora, Scyntalydium, Cladosporium, Scedosporium* in India patients serial studies [26]. In Mexico in a serial patients study of 219 cases 19.1% was caused by melanized fungus [25]. Clinical signs and symptoms seems to keratomycoses caused by white filamentous fun‐ gus, (Figure 36) in rare cases the corneal scraping samples shows brown fungal cells (Figure 37), and in microcultures the identification are made by its morphological characteristics.

**Figure 36.** Keratomycose caused by *Curvularia lunata* showing satellite lesions.

**Figure 37.** Brown hyphae in cornea smear stained with Schiff periodic acid 400X

**Figure 38.** *Curvularia lunata* microcultures from the sample of fungal keratitis in the patient of figure 36

**Candida.** The yeast fungus *Candida albicans, C parapsilosis, C dubliniensis, C tropicalis*, are of‐ ten isolated from corneal samples in patient with keratitis with post surgical trauma like in cornea transplant, meantime the patient is topically treated with corticosteroids (Figure 39), or in diabetic type 1 or 2patients. The infiltrate is dense and similar to bacterial keratitis, but without antibiotic treatment response, are indolent and of chronic course, in smears of the corneal secretion can be observed yeast like cells in the PAS stain (Figure 40).

**Filamentous Melanized fungus.** Many species of opportunistic filamentous melanized (for‐ merly Dematiaceous) fungus related to keratomycoses have been described. *Curvularia, Al‐ ternaria, Phialophora, Scyntalydium, Cladosporium, Scedosporium* in India patients serial studies [26]. In Mexico in a serial patients study of 219 cases 19.1% was caused by melanized fungus [25]. Clinical signs and symptoms seems to keratomycoses caused by white filamentous fun‐ gus, (Figure 36) in rare cases the corneal scraping samples shows brown fungal cells (Figure 37), and in microcultures the identification are made by its morphological characteristics.

**Figure 36.** Keratomycose caused by *Curvularia lunata* showing satellite lesions.

80 Common Eye Infections

**Figure 37.** Brown hyphae in cornea smear stained with Schiff periodic acid 400X

**Figure 38.** *Curvularia lunata* microcultures from the sample of fungal keratitis in the patient of figure 36

The colonies are obtained in 24 to 48 hours, in blood agar mediums, chocolate agar, Sabouraud-Emmons media, it is suggested to make susceptibility test for Fluconazol and Voriconazole or‐ amphotericin B as recommended by CLSI (Clinical and Laboratory Standard Institute)

**Figure 39.** Candida keratomycose in a young male after penetrating keratoplasty for keratoconus

**Figure 40.** Buddy yeast like cells stained with PAS from corneal smear in patient in Figure 39 1000 X.

**Figure 41.** Creamy-white colonies of Candida *tropicalis* in Sabouraud media.
