Antibiotic susceptibility, cytotoxicity, and protease activity of viridans group streptococci causing endophthalmitis

Decamethoxin and chlorhexidine bigluconate effect on the adhesive and biofilm-forming properties of Streptococcus mitis

The aim of the study

Was to investigate the effect of antiseptics on the adhesive and biofilm-forming properties of clinical S.mitis isolates isolated from the oral cavity of patients with an infectious and inflammatory post-extraction complication.

Materials and methods

Twenty four clinical isolates of S.mitis isolated from patients were studied. The studied antiseptics included 0.02% aqueous solution of decamethoxin and 0.05% solution of chlorhexidine bigluconate. Adhesion of clinical isolates under the action of decamethoxin and chlorhexidine bigluconate was determined by the method of V.I. Brillis. The biofilm-forming properties of clinical isolates were studied using the "microtiter plate test" according to G.D. Christensen.

Results

The studied clinical isolates of S.mitis are classified as highly adherent microorganisms. Action of decamethoxin on clinical isolates decreases the adhesion index of the studied isolates in comparison with the adhesion index of the control culture. Action of chlorhexidine bigluconate on S.mitis isolates increases of adhession of the studied clinical isolates in comparison with the control. After the effect of decamethoxin, the optical density of clinical isolates decreased considering the optical density results of the control. The clinical isolates left an average film-forming capacity even after chlorhexidine bigluconate action.

Conclusions

Clinical isolates of S.mitis are highly adherent microorganisms. The antiseptic decamethoxin decreases the adhesion index of these bacteria, while chlorhexidine bigluconate increases the adhesion index of clinical S.mitis isolates. Clinical S. mitis isolates have an average biofilm formation capacity index. The antiseptic decamethoxin inhibits the biofilm formation capacity of S.mitis from medium to low.

Ocular streptococcal infections: A clinical and microbiological review

Streptococcus is a diverse bacterial genus that is part of the ocular surface microbiome implicated in conjunctivitis, keratitis, endophthalmitis, dacryocystitis, and orbital cellulitis which can lead to decreased visual acuity and require surgical intervention. The pathophysiology of S. pneumoniae is well established and the role of the polysaccharide capsule, pneumolysin, neuraminidases, and zinc metalloproteinases in ocular infections described. Additionally, key virulence factors of the viridans group streptococci such as cytolysins and proteases have been outlined, but there is a paucity of research on the remaining streptococcus species. These virulence factors tend to result in aggressive disease. Clinically, S. pneumoniae is implicated in 2.7-41.2% of bacterial conjunctivitis cases, more predominant in the pediatric population, and is implicated in 1.8-10.7% of bacterial keratitis isolates. Streptococcus bacteria are significantly implicated in acute postoperative, post-intravitreal, and bleb-associated endophthalmitis, responsible for 10.3-37.5, 29.4, and 57.1% of cases, respectively. Group A and B streptococcus endogenous endophthalmitis is rare, but has a very poor prognosis. Inappropriate prescription of antibiotics in cases of non-bacterial aetiology has contributed to increasing resistance, and a clinical index is needed to more accurately monitor this. Furthermore, there is an increasing need for prospective, surveillance studies of antimicrobial resistance in ocular pathogens, as well as point-of-care testing using molecular techniques.

Endophthalmitis in children with open eye injury: epidemiology, risk factors, treatment

The article provides an overview of endophthalmitis cases in children with open eye injury — prevalence, causes and treatment results in Great Britain, USA, China, India, Vietnam, Saudi Arabia, and other countries with different healthcare facilities, lifestyle and traditions.

Endophthalmitis panorama in the Jerusalem area

PURPOSE

The spectrum of microbial infections and the pattern of their susceptibility are variable among communities. Researching these data will lead to the establishment of the most appropriate national management strategies. The purpose of this study was to analyze the epidemiological, clinical, microbial spectrum and antibiotic susceptibility of endophthalmitis cases in a tertiary referral center in Jerusalem.

METHODS

Retrospective review of medical charts of patients presenting with endophthalmitis over a 12-year period.

RESULTS

A total of 74 eyes of 70 patients (males 56%) were included. Mean age ± SD at presentation was 60 ± 19.5 years. Exogenous endophthalmitis accounted for 78% of cases, of which 62% followed an intraocular surgery, 21% occurred after intravitreal injections, 10% followed infectious keratitis and 7% were posttraumatic. Endogenous cases were predominantly observed in diabetic patients. Microbial isolates were identified in 44 samples. Of them, gram-positive bacteria were the predominant microorganisms detected in 33 samples (75%); Staphylococcus epidermidis and Enterococcus faecalis were the most commonly detected pathogens. Mean presenting ± SD LogMAR visual acuity (VA) was 2.38 ± 1.21 and it improved at last follow-up to 1.7 ± 1.37 (p = 0.004, paired t test). Cases secondary to gram-positive microbes were associated with improved VA during the follow-up while cases secondary to gram-negative microbes was correlated with poor final VA (p = 0.046, r² = 0.4). There was no evidence of bacterial resistance in the antibiograms for either vancomycin, ceftazidime, ceftriaxone or amikacin.

CONCLUSIONS

Intraocular surgery remains the most common event preceding endophthalmitis with coagulase-negative staphylococci being the most frequently detected microorganisms. The microbial spectrum of endophthalmitis is similar to that in the western world.

Combined Rothia dentocariosa and Streptococcus viridans Corneal Ulcer in an Immunocompromised Patient

Keratitis is a very common condition seen by ophthalmologists. However, many factors can complicate the treatment of this depending on the causative organism and other patient comorbid conditions. The objective of this clinical case report is to highlight the treatment of keratitis caused by Rothia dentocariosa. It also looks at the unique considerations in keratitis presentations for patients immunocompromised by chemotherapy agents. Our patient is a 58 yo female undergoing chemotherapy with folinic acid, fluorouracil, irinotecan, and panitumumab who presented with several days of a red, painful right eye with mucous discharge. Cultures were positive for Rothia dentocariosa and Streptococcus viridans. The patient ultimately underwent a conjunctival flap procedure as medical therapy with proper oral and topical antibiotics failed to resolve keratitis. This case is unique as previously, only a couple of cases of keratitis caused by Rothia dentocariosa have been reported and none of those patients were immunocompromised nor failed antibiotic therapy.

Draft Genome Sequences of Viridans Streptococci Causing Bacterial Endophthalmitis in Humans

The viridans streptococci are a group of bacteria that are commensals of the oral cavity and pharynx. These species tend to cause severe cases of bacterial endophthalmitis with poor prognoses but remain largely uncharacterized in this context. Here, we report the whole-genome sequences of 21 strains of viridans streptococci isolated from endophthalmitis in humans.

Fatal Streptococcus pseudoporcinus disseminated infection in decompensated liver cirrhosis: a case report

Background

Streptococcus pseudoporcinus (S. pseudoporcinus) was first identified in 2006. It cross-reacts with Lancefield group B antigen agglutination reagents and has been misidentified as S. agalactiae. Sites of S. pseudoporcinus isolation include the female genitourinary tract, urine, wounds, and dairy products. The prevalence of vaginal colonization is reportedly between 1 and 5.4%. Two uneventful cases of soft tissue infection caused by S. pseudoporcinus were reported in the past. However, since late 2019, six cases of invasive S. pseudoporcinus infections have emerged in the literature, one of which was fatal.

Case presentation

We describe a fatal case of a Caucasian male with spontaneous bacterial peritonitis associated with bacteremia due to a multidrug-resistant S. pseudoporcinus strain in a patient with decompensated liver cirrhosis. Despite the patient’s good general condition and stable blood test results when he had visited the outpatient clinic for large-volume paracentesis a few days before admission, this time he presented to the emergency department with a rapidly worsening clinical condition and with laboratory features consistent with multiple-organ dysfunction syndrome, and succumbed within a short period.

Conclusions

Contrary to what was thought until recently, multidrug-resistant S. pseudoporcinus may cause invasive, disseminated, fatal disease in humans. According to current limited data, vancomycin, linezolid, daptomycin, levofloxacin, clindamycin, and tetracycline seem to be the most effective antimicrobial agents against multidrug-resistant strains, and should be the empirical choice in cases of disseminated S. pseudoporcinus infection until laboratory antimicrobial susceptibility results are available. Improvements and new approaches for bacterial identification in routine clinical microbiology laboratories may reveal the real spectrum of S. pseudoporcinus infections in humans, which is currently believed to be underestimated. SS. pseudoporcinus could emerge as a serious medical problem in the near future, similar to other β-hemolytic streptococci.

Urgent Vitrectomy with Vancomycin Infusion, Silicone Oil Endotamponade, and General Antibiotic Treatment in Multiple Cases of Endophthalmitis from a Single Day of Intravitreal Injections-Case Series

The aim of this study was to report on the anatomical and functional results of surgical management of seven cases of endophthalmitis related to a single day of intravitreal aflibercept injections. Patients with signs of endophthalmitis who underwent aflibercept injections (seven eyes) performed on the same day were retrospectively evaluated. The data of visual acuity and optical coherence tomography (OCT) within nine months of the follow-up and the treatment and results of microbiological cultures are reported. Four of the total seven cases had a positive bacterial culture outcome (Streptococcus mitis). All patients underwent vitrectomy combined with phacoemulsification when the eyes were not pseudophakic, vancomycin infusion, and silicone oil tamponade within 24 h; additionally, systemic antibiotics were administered intravenously. The final best-corrected visual acuity (BCVA) after the treatment was finger counting or light perception in all cases, and all eyes were saved with disruption of the inner retinal layers and stabilization of the retina in regard to changes related to the wet age-related macular degeneration (AMD). Although the retinal anatomy was mostly preserved, most of the patients affected by Streptococcus mitis-induced endophthalmitis did not regain baseline vision after the therapy.

Prognostic factors associated with visual outcome of salvageable eyes with posttraumatic endophthalmitis

The purpose of this study is to evaluate the prognostic factors associated with visual outcomes in the salvageable eyes with posttraumatic endophthalmitis. We retrospectively reviewed the medical records of all patients diagnosed with posttraumatic endophthalmitis in our hospital between 2008 and 2015. The following information was collected: age, sex, etiology, past medical history, clinical manifestations, wound location, microbiology, blood leukocyte counts, types of interventions, initial visual acuities and final visual acuities. Univariate and multivariate analyses were used to explore the factors associated with final best-corrected visual acuity. In total, 98 eyes of 98 patients were included in our study. Fifty-seven eyes underwent vitrectomy, 27 of them had silicone oil tamponade, 38 eyes received intravitreal ceftazidime only and 3 eyes received intracameral ceftazidime. In univariate analysis, poor initial visual acuity, presence of intraocular foreign body, number of intravitreal injections, retinal detachment and Zone 3 injury were associated with poor visual outcome. In multivariable analysis, poor initial visual acuity, presence of intraocular foreign body and number of intravitreal injections were independently associated with poor visual outcome. The silicone oil group had fewer repeated intravitreal injections than the group without oil tamponade. We concluded that the visual outcome of salvageable eyes with posttraumatic endophthalmitis is associated with initial visual acuity, presence of intraocular foreign body and number of intravitreal antibiotic injections.