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BACTERIAL CONJUNCTIVITIS AND THERAPEUTIC SUPPORT
HAFFARESSAS Y.
Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia e-mail: [email protected]
Abstract
The term conjunctivitis applies to any form of inflammation of the conjunctiva, a thin and transparent membrane that covers the inside of the eyelids and the anterior face of the eyeball except the cornea, but most often refers to bacterial infections, viral infections and allergic reactions of the surface of the eye. Bacterial conjunctivitis is most often due to the following germs: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Haemophilus influenzae, Neisseria gonorrhoeae, Chlamydia trachomatis.
Topical ophthalmic treatments include eye drops, ointments and gels. The prescription of a local antibiotic in ophthalmology corresponds to precise indications and relates to the proper use of antibiotics, particularly with regard to microbial ecology, with the risk of selection of resistant mutants as well as the prescription of antibiotics by the general route. Antibiotherapy promotes the selection of mutants and / or the implantation of resistant strains at the site of infection.
Keywords: Bacterial conjunctivitis, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Haemophilus influenzae, Neisseria gonorrhoeae, Chlamydia trachomatis, Antibiotherapy.
Introduction. Conjunctivitis is an inflammation of the conjunctiva of the eye, of viral, bacterial, allergic or irritative origin. It manifests itself in particular by redness of one or both eyes, associated with itching, tingling, clear or purulent discharge.
Conjunctivitis is an inflammation of the membrane that covers the white part of the eye and the inside of the eyelids (conjunctiva). The cornea is not affected [3]. It causes a redness of the white of the eye and of the inside of the eyelids. Conjunctivitis is frequent and safe for vision in the absence of complication. The eye is red and other symptoms may appear: an itching in the eyelids that can be swollen (palpebral edema); a very moderate pain in the eye; a feeling of sand under the eyelids; clear or purulent flow; eyelids stuck in the morning on waking; a vision blurred but without decreasing visual acuity. It is necessary to distinguish conjunctivitis from other ocular affections which may also be manifested by a red eye [3, 8]:
Keratitis: corneal involvement which results in reduced vision, pain in the light, intense pain. Keratitis must be treated promptly as it endangers vision;
Uveitis: inflammation of the uvea manifested by redness of the eye, decreased vision and the impression of "flying flies";
Glaucoma: elevation of the internal pressure of the eye sometimes resulting in pain in the eyes and
a decrease in visual field (eg: loss of side vision). It must be treated quickly.
There are different types of conjunctivitis. They may be allergic, irritative (or "contact"), viral and bacterial. They are contagious when they are due to viruses or bacteria [3, 8]. In general, allergic conjunctivitis starts in the spring and is often associated with rhinitis. Most often both eyes are affected. It occurs after contact with an allergen. The most common are grass, tree or herbaceous pollen. The eyes are itchy. They are swollen and watery. The factors triggering allergy should be investigated. Irritative, many substances can cause a reaction when they come into contact with the eye (eg preservatives in eye drops or contact lens care products, shampoo, chlorine). The signs resemble those of viral conjunctivitis. Several viruses can cause viral conjunctivitis. Some, very contagious, can cause an epidemic of conjunctivitis in a community. Other viruses are mostly responsible for skin infections that can spread to the eye if the eyelid is affected (eg: herpes labial). Viral conjunctivitis often affects both eyes at the same time. It is not accompanied by purulent secretions. There are also Enterovirus or Adenovirus conjunctivitis. Conjunctivitis due to the molluscum contagiosum virus [18].
Bacterial conjunctivitis, it tends to affect only one eye, at least initially, unlike viral conjunctivitis.
There is an irritation, a sensation of foreign body in the eye and the eyelids are glued on awakening by purulent secretions. The most commonly affected bacteria are: non-typable Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae, Staphylococcus aureus, Neisseria gonorrhoeae, Chlamydia trachomatis, Pseudomonas aeruginosa [11, 15].
Anatomy. The conjunctiva (of conjugere: reunite) is one of the elements of the apparatus of protection of the eyeball with the eyelids and the lacrimal apparatus. It is a transparent mucous [17] membrane lining the posterior surface of the two eyelids. It continues with:
- the skin at the free edge;
- the cornea at the sclero-corneal limbus;
- the epithelium of the lacrimal ducts at the lacrimal points.
The bulbous portion and the palpebral portion are reflected one on the other at the level of the culsde-sac. They delimit between them a virtual cavity formed by the occlusion of the eyelids: the conjunctival cavity.
Figure 1. Anatomy of the conjunctiva
> The palpebral conjunctiva
It is thin and transparent, shiny and moist, pink in color. It is approximately 0.3 mm thick. There are classically three parts:
- the marginal conjunctiva
- the tarsal conjunctiva
- the orbital conjunctiva
> Fornix of conjunctiva
The conjunctiva is reflected at their levels by making a continuous circular fornix. It allows the movements of the globe independently of the eyelids. There are four.
- the upper fornix,
- the external fornix,
- the lower fornix,
- the internal fornix occupied by the caruncle and the semi-lunar fold.
> The bulbar conjunctiva
It is thin and transparent. It is in connection with the eyeball. It has two parts: a scleral portion and a limbic portion.
- the scleral portion extending from the conjunctival fornix to about 3 mm
cornea.
- the limbic portion which produces a ring 3 mm wide which circumscribes the cornea.
> The vascularization
Arterial blood supply
-The posterior conjunctival arteries
They come from the upper and lower palpebral arteries.
The palpebral vascularization forms on the anterior surface of the tarsus an external arch at the orbital border and an internal arch situated near the ciliary margin.
-The anterior conjunctival arteries
They come from the anterior ciliary arteries. In the middle third of the limbus, the anterior conjunctival arteries give:
• radial branches for the peri-corneal plexus,
• subconjunctival recurrent branches which will anastomose with the terminal branches of the posterior conjunctival arteries.
It should be noted the presence, at the level of the conjunctiva, of arteriovenous anastomoses which allow the rapid establishment of a shunt between two territories.
Venous vasculature
The conjunctival veins have a topography modeled on the arterial distribution. The posterior conjunctival network drains towards the palpebral veins and from there into the superior and inferior ophthalmic veins. The anterior conjunctival veins rejoin the anterior ciliary veins which enter the veins of the right muscles.
Lymphatic Vascularization
- a subepithelial superficial network;
- a deep network which drains the previous one and which sits in the fibrous layer.
Histology. The conjunctiva consists of an epithelium and an underlying chorion [20]. - The epithelium:
It is of cylindrical type with 2 courses: one, deep, composed of one to three cubic cellular layers resting on a basal membrane. The other, superficial, made up of cells high cylindrical with some villi on their surface. Lymphocytes, Langerhens cells, and melanocytes are also found in the epithelium.
-The connective tissue:
It has a loose conjunctive surface layer (adenoid), infiltrated by many cellular elements, and a deep fibrous layer of collagen and fiber fibers elastic. This layer is absent in the tarsal conjunctiva.
- The transition zones:
In the marginal portion, the keratinized epithelium of the eyelids becomes non-keratinized stratified squamous. At the level of the fornix the epithelium becomes thicker as well as the chorion which is rich in lymphatic formations. At the level of the limb, there is disappearance of the goblet cells and the cellular layers increase to reach a dozen.
- The glands of the conjunctiva:
• Serous glands: accessory lacrimal glands.
• mucus glands.
• Henle's glands: epithelial invaginations located in the tarsal conjunctiva.
Floral conjunctival commonsale. A healthy conjunctiva is essential for the normal functioning of the eye. Together, conjunctiva and eyelid have the role of maintaining an environment adapted to the correct functioning of the cornea, first element of the refraction. The secretions of the accessory mucous and lacrimal glands are important components of the precorneal lacrimal film. The conjunctiva is open to the outside and constantly contaminated by the adjacent commensal flora and the bacteria of the oropharynx. Variable in time, this flora is the result of a balance between:
• the contamination from the surrounding environment which is a function of geographical location and climate,
• local defenses which are influenced by the age of the subject, the wearing of contact lenses, and an underlying eye disease.
The presence of some bacteria, yeast or filamentous fungi on the conjunctiva is physiological [4]. The composition of this flora varies according to various factors.
- In non-contact healthy adults, Gram-positive cocci accounts for 90% to 96% of the conjunctival flora. These are mainly staphylococci, essentially coagulase negative, and in particular Staphylococcus epidermidis. Staphylococcus aureus, streptococci and enterococci. Gramnegative bacilli are most often germs of the otorhinolaryngologic tract (Haemophilus) and enterobacteria.
The most common Gram-positive bacilli are Propionibacterium acnes and corynebacteria. Yeasts or filamentous fungi may also be present on the conjunctiva, provided by the adjacent flora and by the environment.
Table 1
Conjunctival bacterial flora of the asymptomatic non-contact lens patient [9].__
Germs Frequency
Gram Positive* 71,5%
Staphylococcus aureus 21,7%
Streptococci of the groupsA, B, C, G 4,5%
Streptococcus pneumoniae 4,6%
Group D Streptococci 17,0%
Non-groupable Streptococci 23,7%
Gram Négative 28,5%
Acinetobacter 3,1%
Aeromonas 0%
Branhamella catarrhalis 2,4%
Citrobacter 0,7%
Enterobacter 1,7%
Escherichia coli 0,5%
Haemophilus 7,5%
Klebsiella 1,4%
Moraxella 1,1%
Pseudomonas 2,0%
Proteus 5,5%
Serratia 1,3%
Diverse 1,3%
* This table does not take into account coagulase staphylococci negative
- In healthy adults with soft hydrophilic contact lenses, the flora is often modified, the predominant flora corresponds to the bacteria found in the contact lens cases. The Gram-negative bacilli become largely the majority, the most frequent being the Pseudomonas, the Serratia and the enterobacteria. Filamentous fungi would also be more numerous.
- In children under 6 years of age, certain germs such as streptococci, especially Streptococcus pneumoniae, or Haemophilus influenzae are more common.
- In patients with dermatitis or atopic keratoconjunctivitis, a cutaneous or palpebroconjunctival colonization by Staphylococcus aureus is frequent.
- Patients who are hospitalized on a repetitive or long-stay basis are more likely to have multidrug-resistant bacteria (MRB) in the conjunctiva, which may be responsible for infections of the ocular surface due to favorable factors.
Signs and symptoms. The intensity of the symptoms varies from one patient to another, but also according to the causal pathology. The beginning is often brutal and unilateral.
The chronology of the symptoms [14] begins with palpebral itching, sensations of palpebral heaviness and heat. Patients report at the same time a conjunctival hyperaemia. By following, appears the impression of foreign bodies and grains of sand on the surface of the eye. Watering and low intensity photophobia are sometimes described. The
inspection found the presence of conjunctival and palpebral edema. As the functional signs described above become more intense, a fibrinous cell exudates then yellowish or greenish mucopurulent secretions according to the causative agent. These can cause the two eyelids to mate, mainly when awakening. The slit-lamp examination can not be carried out in the general practitioner's office but this one allows to specify the presence of papillae and the absence of follicle.
Context and environment to be taken into account.
-The age of the patient
The young adult
When the physician detects a risk behavior for sexually transmitted diseases, it is necessary to mention an inclusion conjunctivitis (Chlamydia). It occurs after 6 days incubation generally.
The teenager
Adolescent in swimming pools may be infected with Chlamydia.
The newborn
The conjunctivitis of the newborn is defined by the appearance of a purulent discharge in the first 28 days of life. There are two aetiologies linked by the passage of the newborn in the maternal genital tract:
• To chlamydia: the signs appear 7 to 15 days after the birth and are readily unilateral initially.
• To gonococci: the earlier signs appear between the second and third day.
-Associated pathologies
Lacrimal pathologies: for example, obstruction of the nasolacrimal duct in the newborn may be responsible for lacrimation but sometimes for recurrent bacterial conjunctivitis.
Static palpable disorders: conjunctival irritation, or even bacterial superinfection, may be caused by entropion or ectropion (regardless of etiology).
Chalazions and Styles: often associated with Staphylococcus aureus, their presence is an argument in favor of this bacterium.
Gonorrhea: associated with conjunctivitis, it leads to contamination by the gonococcus.
Fiessinger syndrome Leroy Reiter: it combines urethritis, arthralgia and ocular involvement. It leads to chlamydial contamination.
-The origin of the patient
A patient with a membranous conjunctivitis and originating in an eastern country evokes a diphtheria etiology.
Before a patient from a third world or maghreb country, the diagnosis of trachoma is mentioned.
Case of Trachoma: it is the leading cause of blindness of infectious origin in the world. The germ
in question is Chlamydiae trachomatis. The transmission is carried out either by means of a vector (flies) or by infected ocular secretions (the most frequent case).
Differential diagnostics. They are mainly represented by other acute etiologies of conjunctivitis, viral or allergic.The other acute pathologies to evoke are: keratitis, uveitis, acute glaucoma by closing the angle.
But some chronic pathologies of the ocular surface can be superinfect:
- dry conjunctivitis,
- stenosis of the lachrymal ducts,
- ocular pemphigoid,
- canaliculites ...
Risk factors and gravity criteria.
-Risk factors
They define patients for whom the occurrence of an infection of the surface of the eye can result in serious complications, or even life-threatening complications.
• immunodepression,
• poorly balanced diabetes,
• underlying local pathology: dry syndrome, corneal dystrophy,
• corneal graft, recent eye surgery,
• local corticosteroids,
• wearing of contact lenses,
• disorder of the palpebral static, obstruction of the lachrymal ducts.
• monophthalm,
• new born.
- Criteria gravity
They define a degree of severity that specifies the indication of specialized management (ophthalmologist) and / or local antibiotic treatment. They are a tool for general practitioners but also for the paramedical professions often involved in the front line, such as pharmacists and nurses. They understand:
• Important purulent secretions,
• chemosis,
• palpebral edema,
• severe tearing,
• decreased visual acuity, even moderate,
• photophobia.
The main complication of conjunctivitis is keratitis, which can result in blindness, seeing a purulent melt of the eye.
Place of bacteriological examination. Bacteriological sampling should not be systematic. During the consultation with the doctor, the clinic must be sufficient for the diagnosis. The
identification of a germ requires on average 48 to 72 hours except in the rare cases where it is identified by direct examination. More than 85% of bacterial conjunctivitis treated with antibiotic, empirically, respond favorably in 5 days. It is therefore not reasonable to carry out such a search systematically in everyday practice.
It may nevertheless be useful in certain particular cases, summarized in the table below [6].
Table 2
Signes de gravité pouvant justifier d'un examen
bactériologique._
Depending on the terrain_
purulent conjunctivitis in a newborn
purulent conjunctivitis in immunocompromised
Lens wearer or ocular prosthesis wearer
purulent conjunctivitis in a patient operated for glaucoma or
cataracts
Patient treated chronically with local corticosteroids Concept of infection with Neisseria gonorrhoeae,
menigitidis or Haemophilus influenzae type B_
According to the clinical presentation_
Acute conjunctivitis with membrane or pseudo-membrane Conjunctivitis associated with corneal involvement or corneal abscess
Treatment-resistant chronic conjunctivitis to look for possible Chlamydiae
Acute conjunctivitis recurrent or resistant to 8-day empirical treatment_
The sampling must follow some rules but can be done at the doctor's office. Most often, swabbing is sufficient. We must take the mucopurulent secretions by gently rubbing the conjunctiva from the internal angle to the external angle of the eye, as far as the conjunctival fornix [7]. The laboratory can be transported to a laboratory within a normal period without special precautions. Do not instill a local anesthetic beforehand, avoid the facial toilet before examination and make-up. Ideally, collection should take place before any antibiotic treatment. In the wearer of contact lenses, it is preferable to keep lenses and case to find the causative agent.
The germes involved.
- In the adult
In non-contact lens adults, more than 60% of purulent conjunctivitis is caused by Gram-positive cocci, Staphylococcus aureus and Streptococcus pneumoniae.
-In contact lens wearers
Since the appearance of soft-wearing permanent contact lenses, bacterial infectious complications associated with contact lenses have decreased; The problems of hygiene becoming less common. The most frequently encountered germs are Gramnegative bacilli, and particularly Pseudomonas.
-In the child
The germs involved in the bacterial conjunctivitis of the child vary according to the seasons. Their presence is often related to their recovery from the lacrimal pathways, either by congenital imperforation or by the syndrome of the large cornet in early childhood rhinitis. Thus, the bacteria in question are those usually found in the flora of the upper airways, mainly Haemophilus influenzae and Streptococcus pneumoniae. To a lesser extent, Staphylococcus aureus and Moraxella catarrhalis are found.
■ Haemophilus I Corynebacteria
■ Moraxella
■ Acinetobacter
■ Oral Streptococci including S. pneumoniae
■ Staphylococcus aureus
■ Others
Fig. 2. Percentage frequency of germs involved in purulent conjunctivitis in adults.
-In the newborn
The causative agent to be eliminated is Neisseria gonorrhoeae, at risk of very purulent keratoconjunctivitis. Today, the baby receive systematically the instillation of eye drops (the nature of which varies from motherhood to another) a few minutes after birth.
Therapeutic care. The easiest way to reduce an undesirable bacterial population causing or participating in the formation of conjunctival lesions or infections is by local cleansing. However, in certain situations the purely mechanical effect of washing must be supplemented by an antibacterial topical. Whatever the local treatment, it must be accompanied by rules of hygiene.
-Hygiene rules
It is important to explain these measures to the patient and his / her environment. This period of consultation, which is indispensable, must make it possible to avoid any recurrence or possible chronicity. Finally it avoids transmission to the entourage.
• Washing hands
It is the main rule of hygiene. The patient or the person performing the gestures must wash the hands before and after the completion of eye care. When
bacterial conjunctivitis is minor, see moderate in symptoms and there is no risk factor, then a simple soap wash is sufficient. However, if the bacterial conjunctivitis is more severe, or the bacteriological examination finds an aggressive germ, with or without resistance, the washing should be carried out with povidone iodine or chlorhexidine disinfectants [1]. The practitioner who performs the examination or performs a gesture, is subject to the same rules of hand washing. It avoids possible contamination of its patients.
• Toiletries and make-up
It is preferable that the patient uses toiletries that are not shared with those around him. If this is not the case, they may be disinfected. The same is true for make-up products. But it is necessary to explain to the patients that the use of makeup during an episode of inflammation of the conjunctiva can maintain aggravate this lesion of the ocular surface. The rule is to abstain from any make-up during the treatment of bacterial conjunctivitis. The measures mentioned above constitute the preventive part of the treatment.
• Cleaning of ocular secretions
The ocular secretions that stick or not the eyelid are cleaned on waking. This is the time of day when they are the most important. If they persist they should be cleaned throughout the day and always before the instillation of an eye drops, whether antiseptic or antibiotic.
This washing has a purely mechanical effect. It has several advantages:
-the humidification caused by this gesture allows the elimination of the bacteria contained in the secretions or fixed on the dead cells,
-it reduces the infectious population of whatever nature, the bacterial inoculum in addition, without forgetting the elimination of "foreign bodies" (crusts, cluster of fibrin ...).
-this action increases the effectiveness of antiseptic and antibiotic eye drops,
-it increases the bacteriostatic effect of antibiotic eye drops if prescribed.
In general, the washing is carried out with solutions based on physiological saline and with sterile compresses. In case of bilateral conjunctivitis, one eye at a time should be cleaned and a change of the compress after the care of the first eye. Cleaning is carried out from the inside of the eye to the outside. It is forbidden to go back. The use of single-dose products is preferable to the use of a large-capacity bottle. Indeed, even if the hygiene rules are reminded to the patient, sometimes they are not rigorous. A contamination of the
product leads to the risk of reinstillation of a contaminated eye drops, source of therapeutic failures or recurrences. Thus, the effectiveness of the treatment depends on the observance of the rules of hygiene and the rules of cleaning by the patient and the entourage. The improvement of socioeconomic conditions also plays a crucial role.
-The antiseptic treatment
In the absence of signs of severity, in adults, a saline wash with antiseptic eye drops is sufficient. The choice of the antiseptic is important, in addition to possessing bacteriostatic activity, some possess bactericidal activity. There are six classes:
• metallic: there are several, each in a particular context.
silver nitrate in the prevention of neonatal ophthalmia,
organomercurials for the disinfection of contact lenses,
copper salts in bacterial conjunctivitis with Chlamydiae.
• methylene blue: powerful antiseptic.
• boric acid.
• quaternary ammoniums: they have a broad spectrum, except for Pseudomonas.
• amidines: they are bacteriostatic, some even bactericidal.
• povidone iodine 5%: its spectrum is wide. It removes 90% of colonies microbial growth in less than three minutes.
Several precautions must be taken when prescribing or dispensing these antiseptics. Some antiseptics have a vaso-constrictor effect or are associated with a vaso-constrictor. In the first intention, its associations are to be avoided, because they give rise to side effects that are not negligible. The different constituents may cause allergic local reactions, the prescriber must remain vigilant as to the patient's antecedents. Finally, prolonged use of antiseptics with an ophthalmological aim of more than 15 days exposes the risk of bacterial resistance.
-Antibiotherapy
The antibiotic is not indicated in most cases of conjunctivitis.
> Antibiotics, resistance and public health
Local antibiotic therapy constitutes only a small proportion of all antibiotics received by the general population. Yet their reputation for efficacy and safety contributes to their wide prescription. In routine practice, health professionals using or prescribing antibiotic for ophthalmology are ophthalmologists, general practitioners and pediatricians.
The prescription of a local antibiotic may have undesirable effects on the resident bacterial flora by several mechanisms [22]:
-the alteration of the resident "barrier" flora, whose role is to physiologically oppose colonization by pathogenic agents,
-the selection of resistant bacteria in a pluri-microbial flora. If topical antibiotherapy is short, the risk of selecting antibiotic-resistant mutants is low. On the other hand, in the case of prolonged or inadequate administration, in particular at subinhibitory doses, this risk may (the same applies to the use of antiseptic eye drops). Chronic lesions, by repeated treatments, also increase this risk.
-replacement of the resident flora by an antibiotic-resistant flora.
Numerous studies have analyzed the evolution of the resistance of the germs responsible for ocular damage to antibiotics. They relate primarily to fluoroquinolone resistances. After rising significantly since the 1990s, the prevalence of resistance is stagnating.
• Knauf and al. [12] reported seven cases of ciprofloxacin-resistant Gram-positive bacteria in 1996. These germs had been taken from corneas and conjunctivae. The same working group showed a reduction in the sensitivity of six groups of reference germs to ciprofloxacin out of 3,5308 samples taken between 1988 and 1993:
Pseudomonas aeruginosa (95-90%, p = 0,001), Staphylococcus aureus (96-87%, p < 0,0001), Coagulase-negative Staphylococci (97-81%, p <
0,0001), Enterococcus spp (92-79%, p < 0,0001), Acinetobacter anitratus (97-77%, p = 0,0006), Enterobacter cloacae (100-96%, p = 0,03).
• The percentage of ciprofloxacin-resistant Staphylococcus aureus increased significantly from 5.8% to 35% between 1993 and 1997 [10]. The same was true for resistance to ofloxacin, which increased in the same period from 4.7% to 35%. This was demonstrated by the retrospective study by Goldstein and al. Which involved 1053 specimens from bacterial keratitis.
• At the same time, a similar study showed an increase in the resistance of ciprofloxacin to the bacteria responsible for bacterial keratitis. Among 1558 corneal samples, 30,7% showed resistance [13].
• In 2000, a study published by Alexandrakis [2] showed an increasing incidence of resistance to fluoroquinolones in bacteria isolated from laboratory samples taken between 1990 and 1998. The latter increased by 11-28%. Yet at the same time resistance to aminoglycosides has not changed.
• The study conducted by Tuft and Matheson, also published in 2000, does not show any increase in resistance to cefuroxime and gentamycin between 1984 and 1999. The results have been identical for ofloxacin since 1995 [21].
• The results of the study carried out in the XV / XX [5] Parisian hospital are consistent with the previous study. It shows a stoppage in the tendency to increase the resistance of staphylococci to fluoroquinolones.
Table 3
Sensitivity of the main antibiotics to the most common bacteria.
Aminoglycosides Tetracyclines Chloramphenicol Rifamycin Fluoroquinolones Fucidic acid Baci Trac in
Gram Positives + + + + + + +
Staphylococci Meti-S
Staphylococci Meti-R + + R + R + +
Streptococci R + + + R + +
Gram negatives + + + + + R R
Haemophilus influenzae
Pseudomonas aeruginosa + R R R + R R
Enterobacteria Group III + R R R + R R
Chlamydiae R + + + + R R
+: Sensitive Strain
R: Resistant Strain
All these studies give an outline of the evolution of the resistances of germs to antibiotics in the superficial infections of the eye. But these different publications concern different populations, different geographic locations. It is therefore difficult to compare them.
The resistances do not occur with the same mechanism and the same speed according to the molecules used:
-For fosfocine, rifamycin and fucidic acid the development of resistances is very rapid whereas it is less rapid with fluoroquinolones,
-Resistance to aminoglycosides is rare but generally broad spectrum and crossed with other antibiotics.
> Pharmacokinetics of local antibiotics After instilling a drop of eye drops, the product is diluted in the lacrimal film and distributed over the entire ocular surface. It is then in contact with the cornea, mainly the superficial corneal epithelium, and the conjunctiva which lines the eyeball and the inner face of the eyelids.
Several mechanisms cause the gradual decrease in the concentration of antibiotics over time:
- dilution in the lacrimal film,
- resorption at the level of the conjunctiva,
- removal through lacrimal ducts,
- penetration into the cornea.
The principle of superficial antibiotherapy is to obtain effective concentrations superior to MIC (Minimum Inhibitory Concentration) and lower than the toxic concentrations during a maximum contact time. This contact time depends on the characteristics of the topical: its viscosity, its pH, its osmolarity, the molecule and its adjuvants.
Table 4
Action and intracorneal penetration of topical antibiotics.
Action Intracorneal penetration
Quinolones Bactericidal +++
Aminoglycosides Bactericidal -
Rifamycin Bactericidal ++
Polymyxin B Bactericidal -
Bacitracin Bacteriostatic ++
Chloramphenicol Bacteriostatic +++
Tetracyclines Bacteriostatic ++
Fusidic acid Bacteriostatic ++
> Galenic
The ophthalmological pharmacopoeia proposes three galenics for local antibiotics:
- eye drops (collyrium),
- ointments,
- gels.
Gel and ointment treatments do not necessarily have any advantages in bacterial conjunctivitis. However, it should be pointed out that they allow a remanent effect of the active principle by prolonged contact with the ocular surface. They also provide relief for the patient by dressing effect. On the other hand they are sometimes difficult to spread and can cause a temporary visual fog. This may lead to poor compliance to be taken into account when prescribing.
> Side Effects of Antibiotics
The side effects of antibiotics given topically are very few. This benefit comes mainly from the shortness of the treatment and the doses used. Allergy is the most common side effect. Other effects have been published, sometimes with impact but with no real scientific evidence. Allergy to the active ingredients or preservatives contained in most preparations may cause pruritic conjunctival irritation or contact dermatitis and cessation of treatment. It occurs most often in pre-sensitized patients. Among these allergenic substances, aminoglycosides (Neomycin) are the most often incriminated. The benzalkonium chloride, a frequent preservative in eye drops, is also responsible for allergic reactions.
> Rules for the prescription of a local antibiotic during a conjunctivitis
Only bacterial conjunctivitis requires the prescription of an antibiotic.
When?
The effectiveness of local antibiotics, and hence their value, in bacterial conjunctivitis has been the subject of an abundant literature. The bacterial conjunctivitis is treated by combining an eyewash with physiological saline and an antiseptic, and the antibiotic treatment is reserved for severe forms, ie, in the presence of criteria or factors of gravity. "The clinician must weigh the individual benefit of comfort and contagiousness and the collective risk associated with increased resistance to antibiotics".
How?
The general practitioner or specialist, must try to adapt his antibiotherapy to the germ and the patient.
Patient information is essential. He must be warned of the respect of the duration of the treatment. Generally the prescription lasts one week (7 days). Eye drops can be administered every two hours at the beginning, then three to four times a day. At night, an antibiotic ointment can be combined to increase the contact time and dressing effect. In any case, the instillation of the eye drops
must be carried out imperatively after ocular washing. The antibiotic must be changed in the absence of efficacy after a few days, with the possibility of taking a sample after a therapeutic window of at least 24 hours [19]. Monotherapy remains the most advisable.
Case of pregnant woman
Most studies on the investigation of antibiotic eye drops are commonly prohibited in pregnant women.
-were thus discouraged: kanamycin, chloramphenicol (more marketed),
-should be avoided by caution: aminoglycosides,
-may be prescribed: tetracyclines (during the first trimester), rifamycin, fluoroquinolones (ciprofloxacin, ofloxacin and norfloxacin).
Cases of the child
Haemophilus influenzae and streptococci are the most frequently isolated germs in bacterial conjunctivitis of the child. These are usually acute conjunctivitis mucopurulent with predominant inflammation on the bulbar conjunctiva. Contamination of the conjunctiva occurs from dirty hands or nasopharynx. Conjunctivitis is generally favorable, the cure is complete. The child is not in itself not a criterion of severity, unlike the infant. Mechanical washing with physiological saline and antiseptic must be the first choice treatment. But the problem arises in front of its frequency, its contagiousness and therefore the school eviction that this affection imposes. It disrupts the family balance and is a constraint parents. Rifamycin has the advantage of a broad spectrum, with little resistance. Its orange coloring is a guarantee of compliance. Azithromycin (macrolide) appears to be a interesting alternative.
In infants, the local antibiotic should be prescribed from the outset. In the case of recurrence, an ophthalmologic opinion is strongly recommended to eliminate lacrimal imperforation.
Cases of trachoma and conjunctivitis with Chlamydiae
Contamination is by direct contact (sexually transmitted infections, dirty hands) or indirectly (by flies).
-Conjunctivitis with inclusions of adult and newborn
Unlike other bacterial conjunctivitis, they begin gradually over several weeks. There is no preponderance for this affection according to geography.It may evolve into superficial keratitis. It is a sexually transmitted infection. It is necessary, when taking charge, to look for an infected partner
as well as the association with other sexually transmitted infections.
Two scenarios:
• no extraocular involvement: topical treatment is possible by azithromycin eye drops, or rifamycin second-line. The treatment should last for 6 to 8 weeks.
• extraocular (articular, genital) involvement: the treatment will be oral with 4 tablets of azithromycin 250mg in a single dose.
Under treatment the signs regress without sequelae. In the absence of treatment, progress is made towards spontaneous healing in 1 to 2 years.
In the newborn, Chlamydiae contamination can occur during childbirth. This conjunctivitis represents 40% of neonatal conjunctivitis. Treatment should be systemic and oral (erythromycin for 14 days). Parents should also be treated.
-Trachoma
Second cause of blindness in the world according to the WHO (1995). This disease is the result of repeated infections with Chlamydiae trachomatis. Its main vector is the fly. It is endemic in 48 underdeveloped countries or in the process of development. Contamination is promoted by poor hygiene and poor access to drinking water. Blinding complications are related to the reinfection associated with bronchial superinfections. Treatment begins with preventive measures such as improving hygiene and health education. Treatment of infected individuals is based on the SAFE Strategy: Surgery, Antibiotherapy, Facial cleansing, Change of Environment. For antibiotic therapy, it
may be taken orally by tetracyclines, sulfamides or erythromycin for three weeks. It may also be local by tetracycline ointment for 6 weeks or by macrolide for 3 days. In the underdeveloped countries, where access to products is difficult, mass prophylaxis has been proposed.
> Decision tree
Conclusion. Bacterial conjunctivitis is frequent but rarely threatens eyesight. However, their accurate diagnosis and immediate treatment at the primary level are very important: they help build community confidence and reduce the risk of first resorting to traditional remedies, which in some cases are susceptible blindness.
Acute bacterial conjunctivitis tends to differ from viral conjunctivitis by the presence of a purulent discharge and the absence of chemosis and preauricular adenopathy. The forms of bacterial conjunctivitis that need to be treated differently include neonatal conjunctivitis, gonococcal conjunctivitis, trachoma and conjunctivitis with inclusions. The diagnosis is usually clinical.
Treatment includes measures to prevent the spread and antibiotics (topical, such as fluoroquinolone, except for gonococcal and chlamydial causes).
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БАКТЕРИАЛЬНЫЙ КОНЪЮНКТИВИТ И ЛЕЧЕНИЕ
ХАФФАРЕССАС Я. Нижегородский государственный университет им. Н.И. Лобачевского e-mail: [email protected]
Аннотация
Термин конъюнктивит относится к любой форме воспаления конъюнктивы - тонкой и прозрачной мембраны, которая покрывает внутреннюю часть век и переднюю поверхность глазного яблока, за исключением роговицы, но чаще всего относится к бактериальным инфекциям, вирусным инфекциям и аллергическим реакциям поверхности глаза. Бактериальный конъюнктивит чаще всего обусловлен следующими бактериями: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Haemophilus influenzae, Neisseria gonorrhoeae, Chlamydia trachomatis. Местные офтальмологические методы лечения включают глазные капли, мази и гели. Назначение местного антибиотика в офтальмологии соответствует точным показаниям и относится к правильному использованию антибиотиков, особенно в отношении микробной экологии, с учетом риска выбора устойчивых мутантов, а также назначения антибиотиков по общему маршруту. Антибиотикотерапия способствует выбору мутантов и/или имплантации устойчивых штаммов в месте заражения.
Ключевые слова: Бактериальный конъюнктивит, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Haemophilus influenzae, Neisseria gonorrhoeae, Chlamydia trachomatis, Антибиотикотерапия.
