Biofilms and Physical Deposits on Nasolacrimal Silastic Stents Following Dacryocystorhinostomy: Is There a Difference Between Ocular and Nasal Segments?

Characteristics of Bacterial Biofilm Formation in Nasolacrimal Silicone Tubes Post-dacryocystorhinostomy

PURPOSE

To examine the biofilm formation characteristics of bacteria identified at the genus level in samples obtained from silicone tubes after dacryocystorhinostomy surgery.

METHODS

In the study involving consecutive patients who underwent dacryocystorhinostomy surgery at Ankara Bilkent City Hospital and whose silicone tubes were removed six months after surgery, between January 2023 and May 2023; the tubes were placed in glycerol-PBS (phosphate buffered saline) solution and cultured on descriptive selective media at the genus level. The biofilm-forming properties of the obtained isolates were examined in solid-air and liquid-air interphases. Salmonella Typhimurium ATCC SL1344 strain was used as the control bacterium.

RESULTS

As a result of the analysis of the samples taken from the patients, Pseudomonas spp. was identified in three of the samples, Staphylococcus spp. in five of the samples, and Streptococcus spp. in one of the samples. Among these samples, except for the bacteria identified in samples one and five, the rest were found to be strong biofilm producers. In all strong biofilm producers, the maximum biofilm production time was determined as 72 h and the incubation temperature was 37°C. The presence of cellulose and amyloid proteins in biofilm matrix structures is identified. Swimming and swarming motilities were observed in all bacterial samples.

CONCLUSION

Since biofilms are considered potential factors in the pathogenesis of infectious and inflammatory diseases, they are a subject that needs to be thoroughly investigated. In our study, although there were no clinical infections in any of the patients, biofilm formation was detected in the patient samples. The fact that the bacteria exhibited moderate to strong biofilm formation characteristics suggests that these microorganisms could be persistent infectious agents.

Scanning electron microscopic features of lacrimal drainage silastic stents: Comparison of various Crawford and large-diameter stents

PURPOSE

This study aimed to examine the differences in the biofilms and physical deposits on Crawford stents compared to large-diameter stents.

METHODS

A prospective interventional study was performed on a series of patients undergoing external or endoscopic dacryocystorhinostomy (DCR) and endoluminal lacrimal duct recanalization (ELDR) with either Crawford or large-diameter stents. All the Crawford stents were retrieved at six weeks and the large-diameter ones at eight weeks following the surgical intervention. There was no evidence of post-operative infection in any of the patients. Following extubation, standard protocols of scanning electron microscopy were used to assess the biofilms and physical deposits on the stents.

RESULTS

A total of 15 stents were studied. Of these, twelve were Crawford, and three were large-diameter stents. The Crawford stents were from two different manufacturers. All the stents demonstrated evidence of biofilm formation and physical deposits. The Crawford stents showed thin biofilms and sparse physical deposits, but there were no demonstrable differences amongst stents from different manufacturers. However, the deposits and biofilms were thicker and more extensive in the large-diameter stents than the Crawford ones. The biofilms from all stents showed the presence of polymicrobial communities within the exopolysaccharide matrix.

CONCLUSIONS

The present study found differences in biofilms and physical deposits between Crawford and large-diameter stents. These differences can be partly explained by stent duration, size, and their tissue interactions.

Microbial Metagenomics of the Extubated Lacrimal Stents Following Dacryocystorhinostomy: The Lacriome Paper 4

PURPOSE

To study the metagenome of the microbes present on the extubated lacrimal stents following a dacryocystorhinostomy.

METHODS

A prospective study was performed on 10 consecutive extubated lacrimal stents obtained for the metagenomic analysis from the patients following an endoscopic dacryocystorhinostomy. The stents were extubated at 4 weeks postoperatively under endoscopic guidance and immediately transported on ice to the laboratory. Following DNA extraction and library preparation, a whole shotgun metagenome sequencing was performed on the Illumina platform. The downstream processing and bioinformatics of the samples were performed using multiple software packaged in SqueezeMeta pipeline or MG-RAST pipeline.

RESULTS

The taxonomic hit distribution across the stent samples showed that bacteria were the most common isolates (mean, 69.70%), followed by viruses (mean, 0.02%) and archaea (0.003%). The 3 major phyla identified were Firmicutes, Actinobacteria, and Proteobacteria. The prevalent organisms include Pseudomonas aeruginosa, Staphylococcus aureus, Corynebacterium accolens, Dolosigranulum pigrum, Citrobacter koserii, Staphylococcus epidermidis, E. coli, and Hemophilus influenza . The functional subsystem profiling demonstrated microbial genes associated with metabolism, cellular, and information processing. The functional subsystem categories were metabolism involving carbohydrates, amino acids, DNA and RNA, cell wall or cell capsule biogenesis, membrane transport, virulence, and defense mechanisms.

CONCLUSIONS

The present study is the first whole metagenome sequencing of the microbes isolated from the extubated lacrimal stents. The stents harbor diverse microbial communities with distinct ecosystem dynamics. Further studies on microbes-host interactions in the early postoperative period would provide valuable insights.

Developing the rabbit canalicular injury model: Biophysical changes of masterkaR stents and implications for future research

BACKGROUND

To describe the preparation of a rabbit lacrimal canalicular injury model, assess the canalicular healing, and determine the suitability of this model to study the biophysical changes of mono-canalicular stents.

METHODS

Twelve canaliculi of twelve eyes of six healthy New Zealand white rabbits were included in the study. A canalicular injury model was prepared under general anesthesia. The injury was then repaired using modified Masterka^R stents and peri-canalicular wound closure. The stents were extubated at eight weeks, and specific surgical techniques used to obtain the healed canaliculi. Histopathological analysis was carried out on the canaliculi samples, and the stents were examined ultra-structurally using the scanning electron microscopy (SEM).

RESULTS

At eight weeks, the canaliculus maintained its integrity and demonstrated good healing with epithelium continuity. However, the area of incision and suture showed hyperplastic epithelium with significant sub-epithelial fibrosis. Lacrimal irrigation following stent extubation confirmed patency of all the canalicular systems studied. SEM study revealed the biofilm formation and physical deposits over the external, luminal, and adluminal surfaces of all Masterka^R stents with intervening skip areas. Although these changes were seen all over the stent, the most preferential site for physical deposits and biofilm aggregates was the ampullary portion of the stent's head. None of the rabbits showed any evidence of a post-operative ocular infection or local inflammation.

CONCLUSION

Rabbits are good candidates for the preparation of a lacrimal canalicular injury model. The canalicular tissues demonstrate changes following repair. The biophysical changes on the extubated stents resembled those obtained from the humans.

Surgical procedure of canaliculoplasty in the treatment of primary canaliculitis associated with canalicular dilatation

Background

Primary canaliculitis is a chronic infection of the proximal lacrimal pathway. We aimed to evaluate surgical outcomes of a canaliculoplasty procedure for primary canaliculitis associated with canalicular dilatation.

Methods

This study enrolled 42 primary canaliculitis patients with canalicular dilatation who underwent canaliculoplasty. All patients were treated with canaliculotomy, curettage of canalicular contents and canaliculoplasty with stent placement. Patients’ demographics, clinical features, and follow-up outcomes were evaluated.

Results

There were 12 males and 30 females with a mean age of 66.1 ± 13.9 years. The mean duration time from the first onset of signs/symptoms to diagnosis was 30.6 ± 39.5 months. Epiphora (90.5%) and mucopurulent discharge from punctum (85.7%) were the most common signs. Thirty-three out of 42 patients (78.6%) achieved complete remission with a mean follow-up time of 25.3 ± 12.9 months. There were 3 patients found to have canalicular stenosis due to obstruction after surgery.

Conclusion

Canalicular dilatation is a severe condition of primary canaliculitis, probably due to a combined result of long standing disease and the presence of concretions. The surgical procedure of canaliculoplasty can be a highly effective treatment for primary canaliculitis associated with canalicular dilatation.

Ultrastructure of the lacrimal drainage system in health and disease: A major review

PURPOSE

To provide a systematic review of the literature on the ultrastructural findings of the lacrimal drainage system in healthy state and in few of the disorders studied so far.

METHODS

The authors performed a PubMed search of all articles published with reference to electron microscopic features of the lacrimal drainage pathways. Data captured include demographics, study techniques, scanning or transmission electron microscopic features, presumed or confirmed interpretations and their implications. Specific emphasis was laid on addressing the lacunae and potential directions for future research.

RESULTS

Ultrastructural studies have led to better understanding of the lacrimal drainage anatomy-physiology correlations. Cellular interactions between fibroblasts and lymphocytes could form a basis for pathogenesis of punctal stenosis. Ultrastructural characterization of peri-lacrimal cavernous bodies and changes in primary acquired nasolacrimal duct obstruction (PANDO) led to them being partly implicated in its etiopathogenesis. Electron microscopic characterization of the dacryolith core promises insights into their evolution. Ultrastructural tissue effects of mitomycin-C during a DCR surgery has provided potential evidence of its role in cases with high-risk of failure. Lacrimal stent biofilms are common but their clinical implications are currently uncertain.

CONCLUSION

Ultrastructural exploration of lacrimal drainage system so far has been limited and sparsely explored. The list of unexplored areas is exhaustive. There is a need for the lacrimal Clinician-Scientist to make themselves familiar with techniques and interpretation of electron microscopy to advance the ultrastructural frontier of this science.

Cultures of Proximal and Distal Segments of Silicone Tubes After Dacryocystorhinostomy

PURPOSE

To compare the results of cultures of the proximal and distal segments of silicone tubes after dacryocystorhinostomy.

METHODS

The medical records of patients undergoing a dacryocystorhinostomy and silicone intubation were reviewed. The inclusion criteria were cultures of both distal and proximal stent segments after removal, dye testing, evaluation of the tear meniscus, and notation of the presence or absence of discharge before and after removal. The exclusion criteria included the use of systemic or topical antibiotics within 1 month before tube removal.

RESULTS

Forty-six lacrimal systems in 40 patients were included, with 6 patients having bilateral dacryocystorhinostomies. There were no cases of dacryocystitis at the time of or after tube removal. Four (9%) of the dacryocystorhinostomies failed. Forty-one (89%) of the distal tube segments had positive cultures. The distal tube cultures grew 17 (36%) gram-positive bacteria, 21 (45%) gram-negative bacteria, 7 (15%) skin flora, and 2 (4%) fungi (6 distal segments had mixed cultures). Thirteen (28%) of the proximal tube segments had positive cultures. The proximal tube cultures were 5 (38%) gram-negative bacteria, 4 (31%) gram-positive bacteria, 3 (23%) skin flora, and 1 (8%) acid-fast bacteria. Four (31%) of the proximal tubes with positive cultures grew the same organism as the distal tube segment. Nine (69%) of the proximal tubes with positive cultures grew different organisms than the distal segment. Forty-two (91%) of all the proximal tube cultures were either negative or grew different organisms than the distal segment cultures.

CONCLUSIONS

The proximal segment of a silicone tube after a dacryocystorhinostomy may be a "privileged" area. There is usually a lack of growth or the growth of different organisms than those present on the distal tube segments. This may be explained by the protective nature of the tear film. The findings may also help to explain the low incidence of dacryocystitis in spite of the growth of virulent organisms on the distal tube segment after a dacryocystorhinostomy.

Bacterial Biofilms in Jones Tubes

PURPOSE

To investigate the presence and microbiology of bacterial biofilms on Jones tubes (JTs) by direct visualization with scanning electron microscopy and polymerase chain reaction (PCR) of representative JTs, and to correlate these findings with inflammation and/or infection related to the JT.

METHODS

In this study, prospective case series were performed. JTs were recovered from consecutive patients presenting to clinic for routine cleaning or recurrent irritation/infection. Four tubes were processed for scanning electron microscopy alone to visualize evidence of biofilms. Two tubes underwent PCR alone for bacterial quantification. One tube was divided in half and sent for scanning electron microscopy and PCR. Symptoms related to the JTs were recorded at the time of recovery.

RESULTS

Seven tubes were obtained. Five underwent SEM, and 3 out of 5 showed evidence of biofilms (60%). Two of the 3 biofilms demonstrated cocci and the third revealed rods. Three tubes underwent PCR. The predominant bacteria identified were Pseudomonadales (39%), Pseudomonas (16%), and Staphylococcus (14%). Three of the 7 patients (43%) reported irritation and discharge at presentation. Two symptomatic patients, whose tubes were imaged only, revealed biofilms. The third symptomatic patient's tube underwent PCR only, showing predominantly Staphylococcus (56%) and Haemophilus (36%) species. Two of the 4 asymptomatic patients also showed biofilms. All symptomatic patients improved rapidly after tube exchange and steroid antibiotic drops.

CONCLUSIONS

Bacterial biofilms were variably present on JTs, and did not always correlate with patients' symptoms. Nevertheless, routine JT cleaning is recommended to treat and possibly prevent inflammation caused by biofilms.

Success rate of placement of a bicanalicular stent for partial nasolacrimal obstruction in adults under local, monitored anesthesia care and general anesthesia

Purpose

To study The Kaneka Lacriflow Stent, a self-retaining bicanalicular intubation set that can be placed under local anesthetic, providing a new option to treat epiphora and partial NLDO.

Design

Retrospective chart review.

Subjects

93 adult patients requiring treatment for a partial NLDO were evaluated. Stents were placed in office setting under local/topical anesthetic or in OR (MAC or GEN). The stent is placed with a stylet, and self-retains due to a widened portion sitting distal to the common canaliculis. It does not require recovery from the nose.

Methods:

Outcomes analyzed to evaluate success of stent placement.

Main outcome measure

Success rate of placement of the stent in adults.

Results

Stents left in place for 3 months. Results recorded 1 month after removal. Stents successfully placed in 124 of 136 (91%) eyes. Under local anesthesia in the office setting, 83 of 92 (90%) were placed successfully. Records were complete in 59 patients (78 eyes) and were analyzed further. 33 patients (52 eyes) had stents retained for the full 90 days and had follow-up recorded one-month post removal. Of the patients who retained the stents for 90 days and had full follow-up, 32 patients (51 eyes, 98%) reported improvement in their symptoms, while 1 patient reported no improvement.

Conclusion

Silicone intubation of the NLD in adults is rarely done due to need for general anesthesia. The Lacriflow stent can be successfully placed in the office under local anesthesia offering a new approach for tearing in adults.