Tear Production, Intraocular Pressure, Ultrasound Biometric Features and Conjunctival Flora Identification in Clinically Normal Eyes of Two Italian Breeds of Chicken (Gallus gallus domesticus)

Given the abundance of chickens in Italy, it is important for veterinarians to know the normal state of chickens’ eyes in order to identify any ophthalmic pathological changes. The aim of this study was to determine the normal values of select ocular parameters and to evaluate conjunctival microflora in two Italian chicken breeds. Sixty-six healthy chickens underwent a complete ophthalmic examination, which included a phenol red thread test (PRTT) for the evaluation of tear production and the assessment of intraocular pressure by rebound tonometry. B-mode ultrasound biometric measurements and conjunctival microflora identification were also performed in twenty-seven chickens. Mean PRTT was 23.77 ± 2.99 mm/15 s in the Livorno breed and 19.95 ± 2.81 mm/15 s in the Siciliana breed. Mean intraocular pressure was 14.3 ± 1.17 mmHg in the Livorno breed and 14.06 ± 1.15 mmHg in the Siciliana breed. Reference ranges for morphometric parameters were reported in the two breeds. Twenty-three chickens (85.18%) were bacteriologically positive. Chlamydia spp. antigen was detected in 14.81% of chickens. No positive cultures were obtained for fungi. Normal reference range values for selected ophthalmic parameters were obtained in clinically healthy chickens, which could facilitate accurate diagnosis and better management of ophthalmic diseases in these animals.

Study of the resistance pattern and alteration in the conjunctival flora of patients exposed to repeated antibiotics

AIM: To investigate and analyze the changes in the conjunctival flora of patients exposed to repeated antibiotic usage. In addition, determining the effects of this repeated exposure on the resistance pattern of the conjunctival flora. METHODS: This study included 40 patients, admitted to the Retina Unit of the Research Institute of Ophthalmology. All chosen patients had a minimum of 4 consecutive, monthly intravitreal injections (IVI), some were extended to 6mo or 1y as required. The patients were randomly divided into 3 groups and each group received one kind of antibiotic which was either ofloxacin, moxifloxacin or ceftazidime. All bacterial isolates were tested for antibiotic susceptibility using Kirby-Bauer disc diffusion technique. RESULTS: In this study the conjunctival normal flora at base line culture varied from a predominance of Staphylococcus epidermidis (51.2%), followed by Staphylococcus aureus 14% to Micrococcus species 12.8% and other coagulase negative staphylococci (CONS) 13%. Our results showed an increase in the percentage of Staphylococcus epidermidis among ceftazidime treated eyes during the four visits in comparison to baseline cultures of patients randomized to ceftazidime. In contrast, there was no noticeable increase in Staphylococcus aureus percentage from baseline. In fluoroquinolone treated eyes, we also observed an increase in percentage of Staphylococcus epidermidis from base line. In contrast to ceftazidime treated eyes, the Staphylococcus aureus percentage in fluoroquinolone treated eyes showed an increase from baseline. However, the pattern of the ocular flora composition changed with the exposure to the old and newer generation of fluoroquinolones. We noticed an increase of Staphylococcus epidermidis in moxifloxacin treated eyes than that in ofloxacin treated eyes from baseline. There was no observed difference in the pattern of Staphylococcus aureus regarding exposure to older and newer generations of fluoroquinolones. CONCLUSION: Repeated use of ophthalmic antibiotics not only alters the composition of the normal ocular flora, but also selects for resistant strains.

Assessment of conjunctival flora in eyes with lacrimal passage obstruction before and after successful dacryoendoscopic recanalisation

BackgroundTo investigate conjunctival bacterial flora in eyes with lacrimal passage obstruction before and after dacryoendoscopic recanalisation with lacrimal tube intubation.MethodsOne-hundred fifty eyes with lacrimal passage obstruction that were successfully treated by dacryoendoscopic recanalisation were enrolled. Conjunctival sampling was done for each eye before and 4 months after surgery. The lower fornix was rubbed by a sterile cotton swab, and the collected samples were cultured with several agar plates. Colonies were differentiated and enumerated by standard bacteriological laboratory techniques.ResultsPositive bacterial growth was detected in 42.0% of all the samples before surgery, and the positivity rate significantly decreased to 26.0% after surgery (p=0.0051). The number of strains detected also decreased from 20 before surgery to 9 after surgery, especially pathogenic microorganisms decreased. In addition, drug-resistant bacteria such as penicillin-resistant Streptococcus pneumoniae and methicillin-resistant Staphylococcus aureus were detected in nine eyes before surgery but were detected only in one eye after surgery. Coagulase-negative Staphylococci and Corynebacterium spp., which are common in normal conjunctival flora, accounted for 46.5% of all the isolates before surgery and 80.9% after surgery, showing a significant increase in the rate after surgery (p<0.0001).ConclusionsThis study showed that physiological recanalisation of lacrimal passage after dacryoendoscopic surgery significantly decreased the culture positivity rate of conjunctival sac and the number of microorganism strains detected. It also decreased the number of potentially pathogenic and drug-resistant bacteria and increased the percentages of indigenous bacteria, causing the normalisation of conjunctival flora.

Pre-operative conjunctival flora in patients with local and/or systemic risk factors for post cataract surgery infection in Northern Italy

Purpose: To investigate the pre-operative conjunctival flora in patients undergoing cataract surgery with major local and/or systemic risk factors for developing post-operative infection. Methods: A total of 83 patients underwent bacterial culture and sensitivity testing of conjunctival swabs obtained from both eyes because of local risk factors at the pre-operative visit (i.e. chronic blepharitis, conjunctivitis, or lacrimal system disease), and/or systemic risk factors (i.e. autoimmune or skin disorders) for developing post-operative infection. If the swab was found positive, an antimicrobial susceptibility test was performed, and a specific antibiotic therapy was administered. Surgery was performed when a repeat conjunctival swab (after antibiotic treatment) showed negative cultures. Results: Cultures were found positive in 25.3% of patients. Staphylococcus aureus (18%) and Staphylococcus epidermidis (15%) were the most frequently isolated microorganisms. Gram-negative bacteria, including Pseudomonas aeruginosa, were present in nine cases (8%). Conclusion: Present results showed a low rate of swab positivity compared to previous published data, and slightly different microbial flora. The differences observed may be caused by geographical factors and/or to the specific characteristics of the subgroup of studied patients. Considering that the surface microbial flora is one of the major causes of endophthalmitis, this information may be useful in selecting antibacterial regimens to prevent serious ocular infections, and restrain the increasing problem of antibiotic resistance.