**Author details**

example, the sonication (physical separation technique based on ultrasonic waves) and the use of selective media as MacConkey agar (MCk) and mannitol-salt agar (MSA) seeded by a perfect open streak for a good separation of the microorganisms, for positive and negative Gram bacteria, respectively. Talking about the fungi infections, the good sample collected by the ophthalmologists has been sufficient for a fungi growth and a direct observation of the macromorphology and micromorphology for the identification. However, the molecular techniques have revolutionized the ocular infection and coinfection diagnosis; these techni‐ ques are more sensitive, specific, and rapid and impact in the best outcome for the patient. The molecular techniques consist in the amplification of conserved regions of the different microorganisms involved in ocular infection, for example, Gram (+)/Gram (−) bacteria; Generic Fungi; herpes viruses I, II, and zoster; Cytomegalovirus; *Chlamydia* sp.; adenovirus; *Mycobac‐ terium tuberculosis* complex (MTC) and no *Mycobacterium tuberculosis* complex (NTC)*; Toxo‐ plasma gondii*; and *Acanthamoeba* spp. by polymerase chain reaction (PCR). The PCR helps us for the identification of coinfection caused not only bacteria-bacteria or bacteria-fungi but also

Chocolate agar (ChA), Columbia agar (CA), Brain-Heart Infusion (BHI), Sabouraud dextrose agar (SDA), 37 °C for bacteria

Ocular infection Sample Equipment Storage conditions

Anterior chamber (aqueous

Vitreous humor

**Table 3.** Conditions for the sample collection and storage from ocular infections

growth, 28 °C for fungi growth, and 4 °C for sample conservation

Conjunctivitis Upper and lower eyelid

Endophthalmitis and uveitis

136 Advances in Common Eye Infections

Keratitis/corneal ulcer Limit of the corneal ulcer Alginate applicator 37 °C→ChA, CA, BHI

conjunctiva Cotton applicator 37 °C→ChA, CA, BHI

humor) Sterile syringes 4 °C→ syringes

28 °C→SDA

28 °C→SDA

Finally, the post-analytic phase consists of the interpretation of the results. Most laboratories do not report *Staphylococcus epidermidis* and *Staphylococcus aureus*, because they are part of the ocular surface microbiota; however, the laboratory staff of ocular microbiology knows that these microorganisms can be involved directly in the ocular infection, and these two micro‐ organisms have been reported as the microorganisms most frequently isolated in infectious keratitis [109, 110]. It is important to consider the risk factor associated before deciding whether

In conclusion, the diagnosis of infectious disease is best achieved by applying in-depth knowledge of medical and laboratory science by integrating a strategic view of host-parasite interactions. Clearly, the best outcomes for patients are the result of strong partnerships

the microorganisms isolated are responsible for the infection or are a contamination.

coinfection caused by viruses and parasites with bacteria or fungi.

between the clinician and the laboratory specialist [111].

Carlos Alberto Pantoja-Meléndez1,2\*, Victor M. Bautista-de Lucio1 , Mariana Ortiz-Casas1 , Jonathan Quevedo-Martínez1 and Herlinda Mejía-López1

\*Address all correspondence to: linda.mejia@institutodeoftalmologia.org

1 Institute of Opthalmology Conde de Valenciana, Mexico

2 National Autonomous University of Mexico, School of Medicine, Public Health Department, Mexico
