Search Results (12)

Background/Objectives: The ocular surface is continuously exposed to microorganisms, and disruption of host–microbial balance may lead to infection or postoperative complications. Increasing antimicrobial resistance and biofilm formation have highlighted the need for alternative or complementary non-antibiotic strategies to control ocular surface microbial burden. Liposomal ozonated oil eyedrops have demonstrated antimicrobial and antibiofilm activity in preclinical and preliminary clinical studies. The aim of this study was to evaluate changes in ocular surface microbiological culture results before and after treatment with liposomal ozonated oil eyedrops in a real-world clinical setting. Methods: This was a prospective, observational, real-world pre–post study including 101 eyes from 101 patients undergoing ocular surface microbiological sampling in routine clinical practice. Two samples were obtained per patient: Sample I immediately before treatment and Sample II at the routine follow-up visit after short-course treatment with liposomal ozonated oil eyedrops (1 drop, four times daily, for 4 days). The interval between samples ranged from 3 to 5 days (median 3 days). Microbiological cultures were classified as positive or showing no growth. Paired changes in culture positivity were analyzed using McNemar’s exact test. Results: At baseline, 87 of 101 samples (86.1%) yielded positive cultures, while 14 (13.9%) showed no growth. Following treatment, culture positivity decreased to 11 of 101 samples (10.9%), with 90 samples (89.1%) showing no growth. Among baseline-positive samples, microbiological clearance was observed in 76 cases (87.4%). No cases converted from culture-negative to culture-positive at follow-up. The reduction in culture positivity after treatment was statistically significant (McNemar’s exact test, p < 0.001). Recent antibiotic exposure within 14 days prior to baseline sampling was reported in 8 patients (7.9%). Persistent positive cultures were observed in a minority of cases and were mainly associated with common ocular surface pathogens. Conclusions: In routine clinical practice, short-term treatment with liposomal ozonated oil eyedrops was associated with a significant reduction in ocular surface culture positivity over a short follow-up interval. Full article

Background/Objectives: To investigate the long-term changes in conjunctival bacterial flora before and after dacryoendoscopic recanalization for lacrimal passage obstruction using silicone tube intubation. Methods: This prospective study included 135 eyes with lacrimal passage obstruction that underwent lacrimal passage recanalization and were followed for at least one year. The silicone tubes inserted during surgery were removed three months postoperatively in all cases. The study period was from November 2018 to January 2025. Conjunctival samples were obtained before surgery and at 12 months postoperatively. Aerobic cultures were performed to detect bacterial flora. The culture positivity rate, number of bacterial species identified, and proportion of commensal bacteria were compared before and after surgery. Results: The bacterial culture positivity rate significantly decreased from 36.3% preoperatively to 20.0% postoperatively (p = 0.003). The number of bacterial species detected decreased from 15 to 6, with Gram-negative bacilli decreasing from 6 species to 1. In contrast, the proportion of commensal bacteria such as coagulase-negative staphylococci and Corynebacterium spp. relatively increased from 49.1% to 80.7%. No drug-resistant bacteria were detected postoperatively. Conclusions: Dacryoendoscopic recanalization for lacrimal passage obstruction was shown to achieve long-term normalization of the conjunctival bacterial flora by reducing pathogenic and drug-resistant bacteria and increasing commensal bacteria. These findings suggest that the procedure prior to intraocular surgery in patients with lacrimal obstruction may reduce the risk of postoperative infection. Full article

Background/Objectives: In the context of increasing bacterial resistance and the need for effective ophthalmic antiseptics, this study evaluates the antimicrobial efficacy of Corneial MED^®, a novel ophthalmic solution containing polyhexamethylene biguanide (PHMB) and cross-linked hyaluronic acid. The study investigates the in vitro fungicidal and bactericidal properties of this solution against clinically relevant fungal and bacterial strains and its impact on conjunctival flora in vivo. Methods: The in vitro assessment included time-kill assays to determine the fungicidal or fungistatic activity against Candida albicans, Aspergillus flavus, and Aspergillus fumigatus. The bactericidal activity was evaluated against Staphylococcus aureus (methicillin-sensitive and -resistant), Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli. In vivo, 43 patients undergoing cataract surgery were treated with the solution for three days preoperatively. Results: Corneial MED^® demonstrated a fungistatic effect against C. albicans and A. fumigatus, while it exhibited limited activity against A. flavus. The tested solution effectively reduced bacterial load within minutes, outperforming competitor ophthalmic solutions in activity against P. aeruginosa and E. coli. Conjunctival swabs indicated a significant reduction in bacterial load post-treatment, confirming the solution’s efficacy in reducing potential ocular pathogens. Conclusions: These findings highlight the potential of PHMB-based antiseptic solutions as a viable alternative to traditional disinfectants, particularly for preoperative prophylaxis and infection control. Further clinical trials are needed to confirm long-term safety and efficacy. The combination with cross-linked hyaluronic acid not only enhances tolerability but also extends antimicrobial action, making it a promising candidate for ophthalmic disinfection. Full article

This study aims to characterize the conjunctival flora of patients scheduled for cataract surgery and determine the susceptibility profile of isolated bacteria to several commonly used topical antibiotics. Conjunctival swabs were taken from 44 consecutive patients (25 males, 19 females; mean age of 75.0 ± 12.6 years) who were scheduled for senile cataract surgery at two Italian centers before starting any prophylactic preoperative treatment. Swabs were processed for the detection of the microbial growth and for species identification. Selective culture media were used, and bacteria were identified using the MicroScan Specialty ID Panels (Beckman Coulter^®, Brea, CA, USA). Antimicrobial susceptibility for the following antibiotics (netilmicin, tobramycin, ofloxacin, oxacillin, levofloxacin, moxifloxacin, chloramphenicol, cefuroxime, and azithromycin) were assessed using the Kirby–Bauer disk diffusion method. Susceptibility for oxacillin was useful to identify methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE). Among the swabs analyzed, 61.4% showed only saprophytic flora, 30.7% showed only potential pathogenic flora, and 8.0% showed mixed flora. S. epidermidis (20.5%), S. intermedius (18.2%), and S. aureus (14.8%) were the most frequent isolates; MRSA and MRSE accounted for 8.0% and 6.8% of isolates. Less frequently (9%), Gram-negative bacteria such as Pseudomonas fluorescent, Serratia marcescens, Moraxella lacunata, Morganella morgani, and Stenotrophomonas maltophila were detected. All isolated organisms showed an excellent sensitivity to moxifloxacin and chloramphenicol (range 83–100%, range 67–100%, Gram-positive sensitivity for moxifloxacin and chloramphenicol, respectively; 100% Gram-negative sensitivity for both). A significant percentage of the eyes of candidates for surgery presented potential pathogenic flora alone or in association with saprophytic organisms. Staphylococci were the most frequently isolated bacteria. Tobramycin and Ofloxacin, widely used in the ophthalmic field, are confirmed to have a reduced sensitivity in vitro. Full article

Background: The study of bats is of significant interest from a systematic, zoogeographic, ecological, and physiological point of view. The aim of this study is to investigate the culturable aerobic enteric, conjunctival, and oral bacterial flora of bats to determine their physiological microbiome and to investigate the possible occurrence of pathogenic bacteria. Methods: Five hundred and sixty-seven samples were collected from 189 individuals of four species of troglophile bats (Myotis myotis, Myotis capaccinii, Miniopterus schreibersii, and Rhinolophus hipposideros) living in Sicilian and Calabrian territory (Italy). All samples were tested for Gram-negative bacteria; conjunctival and oral swabs were also submitted to bacteriological examination for Gram-positive bacteria. Results: Four hundred thirteen Gram-negative strains were isolated. Of these, 377 belonged to 17 different genera of the family Enterobacteriaceae and 30 to five other families. One hundred eighty-three Gram-positive strains were isolated. Of these, 73 belonged to the Staphylococcaceae family, 72 to the Bacillaceae family and 36 to four other families. Besides some potentially pathogenic strains, several bacterial species have been found that are common to all the bat species studied. These could perhaps play a physiological or nutritional role. Conclusion: A great variety of bacterial species were identified in the cultivable microbiota of southern-Italian troglophile bats, including several potentially pathogenic strains and numerous putatively symbiotic species. Full article

From a clinical point of view, knowledge of the commensal microbial flora of the conjunctival sac in healthy individuals proves to be of great importance. The aim of this study was to assess the presence and the composition of normal ocular microflora of healthy donkeys. Fourteen clinically healthy donkeys (Equus asinus) participated in the study. After prior ophthalmological examination, which showed no abnormalities, a conjunctival swab was taken from each donkey from the right and left eye. Species-specific identification was based on a morphological assessment of bacterial colonies stained with the Gram technique, as well as on biochemical properties and the disk-diffusion method. Around 82% of samples were positive for bacteria cultivation; Pantoea agglomerans was the most prevalently detected species, followed by Moraxella lacunata. In conclusion, our study made it possible to determine the commensal flora of the conjunctival sac in donkeys. The obtained results also showed discrepancies in the composition of the conjunctival sac flora of donkeys and horses, despite the geographical proximity of performed studies. Knowledge of the commensal conjunctival flora of donkeys is of great clinical importance due to their greater exposure to corneal damage and infections than horses. Full article

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. Full article

Postoperative endophthalmitis after cataract surgery is typically caused by the patient’s own conjunctival normal bacterial flora. A three-step approach is recommended to prevent endophthalmitis: (1) “border control” to prevent microorganisms from entering the eye by disinfecting the ocular surface is the most important measure; (2) bacteria that have gained access into the anterior chamber are reduced by irrigation; (3) bacteria remaining in the anterior chamber and vitreous at the end of surgery are controlled by antibacterial drugs. We have devised a method, “the Shimada technique”, for irrigating the ocular surface with povidone-iodine, a disinfectant with potent microbicidal effect and established effective and safe concentrations for eye tissues. Povidone-iodine exhibits a bactericidal effect for a wide concentration range of 0.005–10%, but 0.1% povidone-iodine has the highest activity and requires the shortest time of only 15 s to achieve microbicidal effect. When used to irrigate the ocular surface every 20–30 s during cataract surgery, 0.25% povidone-iodine is conceivably diluted to around 0.1%. Irrigation with 0.25% povidone-iodine during cataract surgery significantly reduced bacteria contamination rate in the anterior chamber compared with saline (p = 0.0017) without causing corneal endothelial damage. Full article

A multicenter, nonrandomized, prospective, controlled study was conducted to evaluate, as perioperative prophylactic treatment, the anti-infective effectiveness of 0.66% povidone-iodine eye drops (IODIM^®) against the bacterial flora of the conjunctival surface of patients who undergo cataract surgery. Eye drops containing 0.66% povidone-iodine were applied to the eye undergoing cataract surgery; the untreated contralateral eye was used as control. One hundred and twenty patients set to receive unilateral cataract surgery were enrolled in 5 Italian Ophthalmology Centers and pretreated for three days with 0.66% povidone-iodine eye drops. The contralateral eye, used as control, was left untreated. Conjunctival swabs of both eyes were collected at the baseline visit and after three days of treatment, just before the cataract surgery. A qualitative and quantitative microbiological analysis of bacterial presence was evaluated by means of bacterial culture, followed by identification. Methicillin resistance determination was also performed on staphylococci isolates. Bacterial load before and after treatment of the eye candidate for cataract surgery was evaluated and compared to the untreated eye. A reduction or no regrowth on the culture media of the bacterial load was observed in 100% of the study subjects. A great heterogenicity of bacterial species was found. The 0.66% povidone-iodine eye drops, used for three days prior to cataract surgery, were effective in reducing the conjunctival bacterial load. The 0.66% povidone-iodine eye drops (IODIM^®) might represent a valid perioperative prophylactic antiseptic adjuvant treatment to protect the ocular surface from microbial contamination in preparation of the surgical procedure. Full article

The conjunctival bacterial resident and opportunistic flora of dogs may represent a major source of dissemination of pathogens throughout the environment or to other animals and humans. Nevertheless, contamination with bacteria from external sources is common. In this context, the study of the antimicrobial resistance (AMR) pattern may represent an indicator of multidrug resistant (MDR) strains exchange. The present study was focused on a single predisposed breed—Saint Bernard. The evaluated animals were healthy, but about half had a history of ocular disease/treatment. The swabs collected from conjunctival sacs were evaluated by conventional microbiological cultivation and antimicrobial susceptibility testing (AST). The most prevalent Gram-positive was Staphylococcus spp.; regardless of the history, while Gram-negative was Pseudomonas spp.; exclusively from dogs with a history of ocular disease/treatment. Other identified genera were represented by Bacillus, Streptococcus, Trueperella, Aeromonas and Neisseria. The obtained results suggest a possible association between the presence of mixed flora and a history of ocular disease/treatment. A high AMR was generally observed (90%) in all isolates, especially for kanamycin, doxycycline, chloramphenicol and penicillin. MDR was recorded in Staphylococcus spp. and Pseudomonas spp. This result together with a well-known zoonotic potential may suggest an exchange of these strains within animal human populations and the environment. Full article

The study purpose was to assess the efficacy of a preservative-free 0.6% povidone iodine eye drops as perioperative prophylactic treatment for reducing conjunctival bacterial load and the rate of needle contamination in patients undergoing intravitreal anti-vascular endothelial growth factor injection. Enrolled patients were randomized to either the study group (0.6% povidone iodine, three day-prophylactic treatment before the injection) or to the control group (placebo, three day-prophylactic treatment). Conjunctival swabs were obtained before and after the prophylactic treatment in both groups. Intravitreal injections were performed in a sterile fashion. The injection needle and a control needle were collected for microbiological culture. Data from 254 and 253 eyes in the study group and control group, respectively, were analyzed. Bacterial growth from conjunctival swab cultures was significantly lower after 0.6% povidone iodine prophylaxis compared to baseline and to placebo prophylaxis (p < 0.001), showing an 82% eradication rate in the study group. No injection needle showed bacterial contamination in the study group, whereas six needles were culture-positive in the control group (p = 0.015). No serious ocular and non-ocular adverse events were recorded. The 0.6% povidone iodine solution proved an effective treatment in reducing conjunctival bacterial load and risk of needle contamination. Full article

The aim of this study was to investigate the effect of topically applied ocular anesthetic proparacaine on conjunctival and nasal bacterial mucosal flora in patients with dry eye disease. A Schirmer test was done with (group 1) and without (group 2) topical anesthetic proparacaine to 40 patients in each group. Conjunctival and nasal cultures were obtained before and 10 min after performing the Schirmer test. The bacterial culture results and the isolated bacteria were recorded in two groups. Patients’ mean age was 62 years (70 female, 10 male). Before the application of topical anesthetic, 50 (62.5%) and 62 (77.5%) had positive conjunctival and nasal culture, respectively, with the most commonly isolated organism being coagulase-negative Staphylococcus in each group. In group 1 the conjunctival bacterial culture positivity rate decreased from 26 (65%) to six (15%) eyes (p < 0.001); however, this rate decreased slightly from 24 (60%) to 20 (50%) eyes in group 2 (p > 0.05). For the nasal cultures, the bacterial culture positivity rate decreased from 80% to 20% and from 75% to 65% in groups 1 (p < 0.001) and 2 (p > 0.05), respectively. Topical ocular anesthetic proparacaine has antibacterial activity in both conjunctival and nasal flora in patients with dry eye disease. Full article