Francesco Carta

Identification and antibiotic susceptibility of coagulase negative staphylococci isolated in corneal/external infections

AIMS To identify and determine antibiotic susceptibility of coagulase negative staphylococci (CoNS) isolated from patients with chronic blepharitis, purulent conjunctivitis, and suppurative keratitis. METHODS A retrospective review of all culture positive cases of chronic blepharitis, purulent conjunctivitis, and suppurative keratitis between July 1995 and December 1996 was performed. Cases in which CoNS were the sole isolates were analysed. Species identification was performed by using a commercially available standardised biochemical test system. Antibiotic susceptibility to penicillin, gentamicin, tetracycline, erythromycin, ciprofloxacin, and teicoplanin was determined by agar disc diffusion (Kirby–Bauer method). Teicoplanin resistance was confirmed by agar dilution. RESULTS 42Staphylococcus epidermidis, fourS warneri, three S capitis, two S hominis, one each ofS xylosus, S simulans, S equorum, andS lugdunensis were identified. 37 CoNS were penicillin resistant, 12 gentamicin resistant, 28 tetracycline resistant, 18 erythromycin resistant, four ciprofloxacin resistant, and one teicoplanin resistant (MIC, 32 μg/ml). In total, 16 strains were resistant to three or more antibiotics. CONCLUSION Species of CoNS apart from S epidermidis may be isolated from patients with corneal and external infection. Antibiotic susceptibility of CoNS is unpredictable and multiresistant strains are common. As a result, antibiotic susceptibility testing should be performed in all cases of clinically significant ocular infections caused by CoNS.

Bacillus cereus keratitis associated with contact lens wear

OBJECTIVE We report the first case of contact lens-related Bacillus cereus keratitis and ulcer associated with B. cereus contamination of the contact lens case. This is also the first study to investigate and establish the genetic identity of an organism isolated from the cornea and contact lens case in a patient with contact lens-associated keratitis. DESIGN Case report. INTERVENTION AND TESTING Conjunctival swabs and corneal scrapings from the left eye were inoculated for culture. The contact lens case was also cultured. Antibiotic susceptibility testing was determined by agar disk diffusion method. Initial treatment with topical ciprofloxacin and fortified tobramycin was given. Genetic analysis of the bacterial isolates was performed using polymerase chain reaction (PCR) with enterobacterial repetitive intergenic consensus primers (ERIC; ERIC-PCR). Susceptibility of B. cereus to heat and contact lens disinfecting solutions containing hydrogen peroxide, hydrogen peroxide-catalase, polyquaternium-1, and polyaminopropyl biguanide (PAPB) was tested. MAIN OUTCOME MEASURES Clinical features, culture results, and antibiotic susceptibility testing were analyzed. The ERIC-PCR amplification products were visualized in ethidium bromide-stained agarose gel. Bacterial growth after exposure to heat and contact lens disinfecting solutions was assessed on blood agar plates. RESULTS B. cereus was grown from the conjunctiva, corneal ulcer, and contact lens case. All isolates were sensitive to gentamicin, tobramycin, ciprofloxacin, clindamycin, and vancomycin. The corneal ulcer gradually healed over the next 6 days. Results of ERIC-PCR showed that the isolates from the cornea and contact lens case were indistinguishable, thus demonstrating the source of infecting organism to be the contaminated contact lens case. Exposure to a temperature of 80 degrees C for 20 minutes and incubation with hydrogen peroxide-catalase, polyquaternium-1, and PAPB for the minimum recommended time failed to kill B. cereus. Only exposure to hydrogen peroxide for 4 hours eradicated the organism. CONCLUSIONS B. cereus should be considered a possible etiologic agent of contact lens-associated keratitis. Heat and many types of contact lens disinfecting solutions may be ineffective in eradicating B. cereus from contaminated contact lens cases. Only prolonged exposure to hydrogen peroxide appeared to be sporicidal to B. cereus in this study.

Susceptibility of Acanthamoeba castellanii to contact lens disinfecting solutions.

A corneal isolate of Acanthamoeba castellanii was exposed to commercial contact lens disinfecting solutions containing hydrogen peroxide, benzalkonium chloride, polyaminopropyl biguanide, polyquaternium 1, and chlorhexidine-thimerosal. The minimum trophozoite amebicidal concentration and exposure times required to kill trophozoites and cysts were determined. Solutions containing hydrogen peroxide or chlorhexidine-thimerosal were active against both trophozoites and cysts. The benzalkonium chloride-based solution was effective only against trophozoites. Solutions containing polyaminopropyl biguanide or polyquaternium 1 were completely ineffective. The need for adequate exposure times must be stressed.

Visual prognosis after indirect traumatic optic neuropathy

Objective: To investigate a possible correlation between final visual acuity and the presence at baseline of various systemic and local (orbital/ocular) signs in patients affected by indirect traumatic optic neuropathy. Methods: 35 cases of traumatic optic neuropathy were examined retrospectively and 13 variables were tested. Univariate analysis with “no recovery of visual acuity” as the primary outcome was performed. Relative risk (RR) and 95% confidence intervals (CI) were calculated. Fisher’s exact test was used for two variables to test differences between proportions. Results: Four variables showed a significantly increased risk for no recovery of visual acuity: presence of blood within the posterior ethmoidal cells (RR = 2.25, 95% CI 1.25 to 4.04); age over 40 years (RR = 1.79, 1.07 to 2.99); loss of consciousness associated with traumatic optic neuropathy (RR = 2.21, 1.17 to 4.16); and absence of recovery after 48 hours of steroid treatment (p < 0.01, Fisher’s exact test). Recovery documented at the first follow up visit after treatment was significantly associated with recovery at the last follow up visit (p < 0.01, Fisher’s exact test). Conclusions: These four negative prognostic signs in patients affected by traumatic optic neuropathy may be useful in predicting the visual outcome in patients developing visual loss after head trauma and in deciding on the need for surgical treatment.

Effect of oral linoleic and γ-linolenic acid on meibomian gland dysfunction

Purpose: To assess the effect of oral linoleic and γ-linolenic acid, 2 ω-6 essential fatty acids, on meibomian gland dysfunction (MGD). Methods: Fifty-seven patients with MGD (27 men and 30 women) were randomly divided into 3 groups of 19. Group A received tablets containing linoleic acid (28.5 mg) and γ-linolenic acid (15 mg) once daily. Group B performed eyelid hygiene once daily. Group C received both treatments. Initially and after 60 and 180 days of therapy, all patients completed a self-evaluation questionnaire on ocular surface disorders and underwent slit-lamp examination. The following signs were evaluated: eyelid edema, eyelid margin hyperemia, meibomian secretion appearance, meibomian gland obstruction, foam collection in the tear meniscus, conjunctival hyperemia, conjunctival papillae, and corneal staining. Results: Statistically significant improvement in symptoms occurred in all groups. After 180-day therapy, group A showed significant reduction in secretion turbidity (P = 0.02) and meibomian gland obstruction (P = 0.0001), whereas group B had significant reduction in eyelid edema (P = 0.02), corneal staining (P = 0.01), secretion turbidity (P = 0.01), and meibomian gland obstruction (P = 0.0001). Group C had significant reduction in eyelid edema (P = 0.003), foam collection in the tear meniscus (P = 0.02), corneal staining (P = 0.02), secretion turbidity (P = 0.0001), and meibomian gland obstruction (P = 0.0001). Conclusions: Therapy with linoleic and γ-linolenic acid tablets along with eyelid hygiene improves symptoms and reduces eyelid margin inflammation in MGD more than either ω-6 fatty acids or eyelid hygiene alone.

Mycoplasma hominis parasitism of Trichomonas vaginalis

Vaginal infections during pregnancy are a risk factor for intrauterine growth retardation, preterm birth, and perinatal mortality or morbidity. Studies of pregnant and non-pregnant women have shown an association between Trichomonas vaginalis and Mycoplasma hominis infections. In an African area with a high prevalence of trichomoniasis, we noticed anti- Mycoplasma antibodies in an unexpectedly high number of women with anti- Trichomonas antibodies. Because an electron-microscopy study showed Mycoplasma organisms in food vacuoles of protozoa, we investigated the cohabitation of the two micro-organisms in the vagina.

Adherence of ocular isolates of Staphylococcus epidermidis to ACRYSOF intraocular lenses: A scanning electron microscopy and molecular biology study

PURPOSE To investigate the adherence of two clinically relevant ocular isolates of Staphylococcus epidermidis to ACRYSOF intraocular lenses (IOLs) (Alcon Surgical, Fort Worth, Texas) and to determine whether the strains under study carried the intercellular adhesion (ica) locus, which encodes production of S. epidermidis antigens mediating adherence to biomaterials. DESIGN Experimental study. PARTICIPANTS The authors examined the in vitro adherence of two clinically relevant ocular isolates of S. epidermidis (S. epidermidis 1 and S. epidermidis 2). Adherence was tested on six ACRYSOF IOLs. METHODS Three IOLs were placed in three separate test tubes containing 5 ml of S. epidermidis 1 suspension, and three other IOLs were placed in three test tubes containing 5 ml of S. epidermidis 2 suspension. At different times (3, 30, and 90 minutes), the IOLs were removed from the test tubes and rinsed in sterile phosphate buffered solution. The lenses were then fixed in glutaraldehyde, postfixed in osmium tetroxide, and serially dehydrated in ethyl alcohol. After critical point drying, they were sputter-coated with gold and then examined with a scanning electron microscope. In addition, polymerase chain reaction amplification was used to investigate whether the isolates under study carried the ica locus. MAIN OUTCOME MEASURES The number of adhered bacteria per area (square millimeters) of IOL optic was calculated. Statistical analysis included calculation of arithmetic means and 95% confidence intervals (t test). Polymerase chain reaction amplification products were visualized in ethidium bromide-stained agarose gel. RESULTS Direct counting of adherent bacteria in scanning electron microscopy photographs revealed that the total amount of adhered bacteria per area of IOL optic after 3, 30, and 90 minutes of incubation in bacterial suspension was 1306/mm(2), 3389/mm(2), and 7195/mm(2) (S. epidermidis 1) and 778/mm(2), 1056/mm(2), and 3861/mm(2) (S. epidermidis 2). Differences at 30 and 90 minutes were statistically significant (P: = 0.01 and 0.02, respectively). Polymerase chain reaction amplification revealed that S. epidermidis 1 contained the ica locus, whereas S. epidermidis 2 was ica negative. CONCLUSIONS Different ocular isolates of S. epidermidis may differ significantly with regard to adherence to ACRYSOF IOLs. Adherence appeared to be greater when the bacterial DNA contained the ica locus. Strains of S. epidermidis carrying the ica locus may play an important role in the pathogenesis of some forms of endophthalmitis occurring after cataract surgery.

Endogenous Rhodotorula minuta and Candida albicans endophthalmitis in an injecting drug user.

Editor,—Although still uncommon, endogenous fungal endophthalmitis has increased notably owing to widespread use of immunosuppressive therapy, hyperalimentation, and injecting drug use. Candida is the most common causative organism with isolated cases of Aspergillus reported.1 Rhodotorula species are ubiquitous, airborne, asporogenous yeasts recovered from food, air, soil, water, gastrointestinal tracts, and skin. Rhodotorula spp are usually environmental saprophytes; however, they may seldom cause both systemic and ocular infections, especially in immunocompromised patients.2Reported ocular infections include chronic dacryocystitis,3 keratitis,4 chronic postoperative endophthalmitis,5 and corneal lamellar graft infection.6 We report a case of endogenous Rhodotorula minuta and Candida albicans endophthalmitis in an injecting drug user. ### CASE REPORT A 27 year old man was admitted with a 3 month history of progressive visual loss and intraocular inflammation in his right eye. He had initially been examined by other ophthalmologists who observed two large yellow-white lesions with fluffy borders in the posterior pole, diagnosed toxoplasmic …

Discoid lupus erythematosus of the eyelids associated with staphylococcal blepharitis and Meibomian gland dysfunction.

Lower eyelid involvement occurs in 6% of patients with discoid lupus erythematosus (DLE). Eyelid lesions are rarely the initial manifestation of DLE. We describe a 25‐year‐old woman presenting with discoid lesions of the lower eyelids, staphylococcal blepharitis and Meibomian gland dysfunction, who later developed a discoid lesion on the chin. Histopathological and immunofluorescence studies of a biopsy specimen from this lesion established the diagnosis of DLE. We are unaware of any previously reported cases of DLE presenting with discoid eyelid lesions associated with staphylococcal blepharitis and Meibomian gland dysfunction. DLE should be considered as a differential diagnosis in chronic blepharitis that persists despite usual medical management and eyelid hygiene. Misdiagnosis may lead to eyelid margin deformities, necessitate a complicated full‐thickness biopsy, and delay diagnosis of systemic lupus.

Glucose 6-phosphate dehydrogenase deficiency and cataract of patients in Northern Sardinia

We determined the activity level of glucose 6-phosphate dehydrogenase in 467 patients with cataract from northern Sardinia. Of 226 men, 18 (8%) had glucose 6-phosphate dehydrogenase deficiency. Of 241 women, 30 (12%) were heterozygous and two (1%) were homozygous for glucose 6-phosphate dehydrogenase deficiency. These prevalences were not significantly different from those expected in the general population. We concluded that patients with glucose 6-phosphate dehydrogenase deficiency do not have a higher risk of developing cataract.