Streptococcus mitis/oralis endophthalmitis management without phakic intraocular lens removal in patient with iris-fixated phakic intraocular lens implantation

Does corneal tattooing affect the conjunctival microbiota?

PURPOSE

This study aimed to investigate the effects of commercial tattoo inks used in corneal tattooing on conjunctival microbiota.

METHOD

This prospective case control study consisted of 125 participants divided in the following three groups: 35 patients with corneal tattoos, 40 patients with corneal leukoma, and 50 healthy subjects. Corneal tattooing was performed in all the cases in this study using a tattoo pen machine and commercial tattoo ink. A total of 500 cultures were taken from 250 eyes of 125 individuals on chocolate and sheep blood agar. Bacteriological samples were taken from the inferior eyelid conjunctiva using a sterile cotton swab. Without any contact elsewhere, the swabs were smeared on bedside chocolate agars and 5% sheep blood agar.

RESULTS

In tattooed eyes, bacterial growth was detected in 42.9% of the chocolate and sheep blood agar samples. In other healthy eyes of patients with corneal tattoos, 54.5% bacterial growth on chocolate agar and 57.1% on sheep blood agar were detected. No statistical difference was detected in the conjunctival microbiota of chocolate and sheep blood agar (p = 0.254, p = 0.134, respectively) in the tattooed eyes compared to the other eye of the individual. No statistically significant difference was found in terms of bacterial growth in tattooed, leukoma, or healthy eyes on chocolate and sheep blood agar (p = 0.408, p = 0.349). The growth rate of Staphylococcus epidermidis decreased by 33.3% (from 12 to 8) on chocolate agar in 35 tattooed eyes, and it decreased by 28.5% (from 14 to 10) on sheep blood agar, while gram-negative bacteria Brevundimonas diminuta, Acinetobacter lwoffii, and Psychrobacter faecalis were detected in three patients.

CONCLUSION

Corneal tattooing using commercial dye does not affect conjunctival microbiota. In the past 3 years, 120 patients have been tattooed with commercial tattoo ink in Istanbul Medeniyet University Göztepe Training and Research Hospital. No complications related to infection were found in the 3-year follow-up. The gram-negative bacteria detected in the healthy control group and tattooed eyes were bacteria found on normal skin or in the respiratory tract. Although some gram-negative bacteria do not cause infection, careful eye examination, follow-up, and culture are required in suspicious cases.

A Case of Urinary Tract Infection Caused by Multidrug Resistant Streptococcus mitis/oralis

S. mitis/oralis has been previously reported in isolated cases of bacterial endocarditis and liver abscesses. Its presence in urine is generally considered a contaminant. A 66-year-old male patient was admitted to the hospital due to recurrent chest tightness and four-year history of exertional dyspnea. On the second day of admission, the patient presented with urgent and frequent urination, as well as dysuria. Both initial and subsequent urine cultures showed S. mitis/oralis infection, with polymorphonuclear leukocyte phagocytosis observed in the second sample. MALDI-TOF results confirmed the isolated strain as S. mitis/oralis. Drug susceptibility testing revealed multidrug resistance to penicillin, ceftriaxone, cefepime, levofloxacin, ofloxacin, and tetracycline, but sensitivity to quinupristin/dalfopristin, vancomycin, and linezolid. The clinician then prescribed vancomycin for anti-infective treatment, which proved effective. Keywords: S. mitis/oralis, UTI, MDR, phagocytosis.

Association between the site of clear corneal Phakic intraocular lens implantation incisions and the inflow of ocular surface fluid into the anterior chamber

Background

Posterior chamber phakic intraocular implantable collamer lens (ICL) implantation is an effective surgical option for the management of myopia. Over the past few years, the number of ICL surgeries has significantly increased. Postoperative inflammation and endophthalmitis are among the most serious complications after successful ICL surgery. Sometimes, when the blepharospasm is removed at the end of surgery, a small amount of the ocular surface fluid will flow into the anterior chamber, which can lead to an increased risk of infection and inflammation. However, little attention has been paid to this phenomenon.

Purpose

We conducted a retrospective study to compare the incidence of extraocular fluid inflow into the eye through the clear corneal incision (CCI) at two different positions (superior and temporal sides).

Methods

A total of 116 patients with myopia underwent superior CCI ICL implantation (n = 58) or temporal CCI ICL implantation (n = 58) at our hospital from October to December 2021. The incidence of conjunctival sac fluid entering the anterior chamber after eyelid fixative was removed was compared in both groups.

Results

Both groups were well matched in all parameters. Ocular surface fluid inflow into the anterior chamber was significantly higher in the superior CCI group (25/58, 47.1%) than in the temporal CCI group (1/58, 1.7%) (p < 0.05).

Conclusion

In the patients with ICL implantation, the temporal CCI was better than the superior CCI in avoiding the ocular surface fluid inflow into the anterior chamber, and the potential risk of infection and inflammation was lower.

Streptococcus mitis/oralis Corneal Ulcer in a Patient with Severe Rheumatoid Arthritis: An Unusual Route

Purpose

To report a case of Streptococcus mitis oralis (S. mitis/oralis) corneal ulcer in a patient with a possible preventable cause.

Methods

Cultures were obtained from a 64-year-old woman with a 3.5 mm × 5 mm corneal ulcer with hypopyon in the left eye.

Results

Culture reports demonstrated the growth of S. mitis/oralis, a commensal organism of the oral flora. Fortified vancomycin 5% eye drops were started, and the patient was counseled on the rarity of the bacteria as an etiology of corneal ulcers. On the return visit, the patient, who works in a doctor's office, volunteered information that the preservative free artificial tear vials that she used were difficult to open because of her hand deformity due to rheumatoid arthritis; thus, she had to bite the vials open.

Conclusions

S. mitis/oralis is an organism commonly found in the mouth but is rarely found in the eye. We report a unique case of an immunocompromised patient with rheumatoid arthritis, severe dry eye, and a history of multiple episodes of keratolysis, who developed a corneal ulcer from a rare pathogen, with a plausible and preventable route of infection.

Amniotic membrane transplantation in a patient with impending perforated corneal ulcer caused by Streptococcus mitis: A case report and review of literature

BACKGROUND

Streptococcus mitis (S. mitis) is an opportunistic pathogen that can lead to severe ocular infections. In previous reports, penetrating keratoplasty (PK) was usually adopted for the treatment of persistent corneal ulcers. This report describes an unusual case of nonhealing descemetocele caused by S. mitis treated by antibiotics plus amniotic membrane transplantation (AMT).

CASE SUMMARY

A 63-year-old woman presented with a right persistent corneal ulcer that she had suffered from for the past 9 mo. The culture of a corneal scraping yielded S. mitis. The right eye descemetocele decreased in diameter from 3 to 0.8 mm after the continuous administration of topical vancomycin and ceftriaxone for 2 wk. Due to the slow healing, AMT was performed. Her corneal erosion healed and gradually became clear. Her visual acuity recovered from initially counting fingers to 100/200 at the last follow-up, 67 mo after AMT.

CONCLUSION

Antibiotics plus AMT may be an effective alternative treatment other than PK to promote epithelialization and to reduce inflammation in the corneas complicated by S. mitis keratitis.

Inhibition of Fibrinolysis by Streptococcal Phage LysinSM1

Expression of bacteriophage lysin_SM1 by Streptococcus oralis strain SF100 is thought to be important for the pathogenesis of infective endocarditis, due to its ability to mediate bacterial binding to fibrinogen. To better define the lysin_SM1 binding site on fibrinogen Aα, and to investigate the impact of binding on fibrinolysis, we examined the interaction of lysin_SM1 with a series of recombinant fibrinogen Aα variants. These studies revealed that lysin_SM1 binds the C-terminal region of fibrinogen Aα spanned by amino acid residues 534 to 610, with an affinity of equilibrium dissociation constant (K_D) of 3.23 × 10^-5 M. This binding site overlaps the known binding site for plasminogen, an inactive precursor of plasmin, which is a key protease responsible for degrading fibrin polymers. When tested in vitro, lysin_SM1 competitively inhibited plasminogen binding to the αC region of fibrinogen Aα. It also inhibited plasminogen-mediated fibrinolysis, as measured by thromboelastography (TEG). These results indicate that lysin_SM1 is a bi-functional virulence factor for streptococci, serving as both an adhesin and a plasminogen inhibitor. Thus, lysin_SM1 may facilitate the attachment of bacteria to fibrinogen on the surface of damaged cardiac valves and may also inhibit plasminogen-mediated lysis of infected thrombi (vegetations) on valve surfaces. IMPORTANCE The interaction of streptococci with human fibrinogen and platelets on damaged endocardium is a central event in the pathogenesis of infective endocarditis. Streptococcus oralis can bind platelets via the interaction of bacteriophage lysin_SM1 with fibrinogen on the platelet surface, and this process has been associated with increased virulence in an animal model of endocarditis. We now report that lysin_SM1 binds to the αC region of the human fibrinogen Aα chain. This interaction blocks plasminogen binding to fibrinogen and inhibits fibrinolysis. In vivo, this inhibition could prevent the lysis of infected vegetations, thereby promoting bacterial persistence and virulence.

Detection and expression analysis of tet(B) in Streptococcus oralis

Tetracycline resistance can be achieved through tet genes, which code for efflux pumps, ribosomal protection proteins and inactivation enzymes. Some of these genes have only been described in either Gram-positive or Gram-negative bacteria. This is the case of tet(B), which codes for an efflux pump and, so far, had only been found in Gram-negative bacteria. In this study, tet(B) was detected in two clinical Streptococcus oralis strains isolated from the gingival sulci of two subjects. In both cases, the gene was completely sequenced, yielding 100% shared identity and coverage with other previously published sequences of tet(B). Moreover, we studied the expression of tet(B) using RT-qPCR in the isolates grown with and without tetracycline, detecting constitutive expression in only one of the isolates, with no signs of expression in the other one.

This is the first time that the presence and expression of the tet(B) gene has been confirmed in Gram-positive bacteria, which highlights the potential of the genus Streptococcus to become a reservoir and a disseminator of antibiotic resistance genes in an environment so prone to horizontal gene transfer as is the oral biofilm.

Successful management of late-onset Streptococcus mitis endophthalmitis

Endophthalmitis following intraocular surgery can be devastating. This case report demonstrates successful management of late-onset Streptococcus mitis endophthalmitis treated by vitrectomy, panretinal photocoagulation (PRP) and silicone oil tamponade. A 75-year-old man presented with painful vision loss in his right eye. The patient had uneventful phacoemulsification and intraocular lens implantation in the right eye at an outside clinic 6 weeks prior. Examination disclosed hypopyon and vitritis, as well as discrete inflammatory collections in the vitreous. The patient underwent vitrectomy with PRP and silicone oil tamponade. Vitreous cultures were positive for S. mitis, a pathogen associated with severe tissue damage and poor clinical outcomes. One month after the surgery, intraocular inflammation was stabilized, and visual acuity was improved from light perception to 20/200. Aggressive surgical management may play a role in improving outcomes in these patients.

Successful re-implantation of implantable collamer lens after management of post-ICL methicillin-resistant Staphylococcus epidermidis endophthalmitis

A 29-year-old man presented with acute onset pain, redness and diminution of vision in the right eye 5 days after implantation of an implantable collamer lens (ICL). A diagnosis of postoperative endophthalmitis was made based on examination and ultrasonography. A vitreous tap was taken and intravitreal antibiotics (vancomycin 1 mg/0.1 ml+piperacillin-tazobactam 225 µg/0.1 mL) were administered. The vitreous culture revealed presence of methicillin-resistant Staphylococcus epidermidis. There was minimal improvement after 48 h; hence the ICL was explanted and repeat injection of intravitreal antibiotics administered. Following this, the endophthalmitis resolved and the patient achieved a corrected distance visual acuity of 20/25 4 weeks later. A repeat implantation of ICL was performed 9 months after the first surgery, following which the patient regained uncorrected distance visual acuity of 20/20. To our knowledge, this is the first case in which an ICL was re-implanted after successful resolution of endophthalmitis.