Presence of the blaTEM Gene in Commensal Neisseria spp.: A Possible Cause for the Acquired Drug Resistance Among Pathogenic Respiratory Bacteria.

Background The oral microbiome consists of various bacterial genera, with Neisseria spp. being a prominent part of this niche. While Neisseria gonorrhoeae and Neisseria meningitidis are human-restricted pathogens, non-pathogenic Neisseria species like Neisseria sicca, Neisseria perflava, etc., are primarily commensals that can also behave as opportunistic pathogens. With increasing penicillin resistance in commensal Neisseria, there is a concern that these bacteria might harbor resistance genes that can be transferred to other pathogens. This study aimed to characterize the blaTEM gene (encodes for the plasmid-mediated ß-lactamase enzyme that hydrolyzes the ß-lactam ring) of commensal Neisseria spp. isolated from respiratory samples. Methodology The research was conducted in the Department of Clinical Microbiology at Sri Ramachandra University, Chennai. The specimens used were sputum and throat swabs, which were subjected to a series of phenotypic methods and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) for speciation. The antibiogram was determined using the Kirby-Bauer disk diffusion method, and a PCR assay was utilized to identify the blaTEM gene responsible for ß-lactamase production. Results Out of 274 processed samples, 65 unique commensal Neisseria spp. were identified. The study highlighted the presence of the blaTEM gene in 93.9% (61) of the isolates, which is responsible for ß-lactamase production. All isolates exhibited resistance to penicillin. Most blaTEM-positive commensal Neisseria spp. were susceptible to cefuroxime (83.6%), ceftriaxone (85.2%), and cefotaxime (85.2%). The high prevalence of the blaTEM gene in commensal Neisseria is alarming. The gene, found on plasmids, could potentially transfer to other related species like Neisseria gonorrhoeae and Neisseria meningitidis, as well as other Gram-negative bacilli. Conclusion The presence of resistance genes in commensal bacteria is of concern, as they might be reservoirs for resistance transfer to pathogenic strains. The study emphasizes the importance of continuous monitoring and deeper investigations into commensal bacteria, emphasizing the need for a broader community screening approach to understand resistance mechanisms in the normal microbiome.

Antimicrobial efficacy of zinc oxide nanoparticle-coated aligners on Streptococcus mutans and Candidaalbicans.

INTRODUCTION: This study aimed to assess the antimicrobial effect of zinc oxide (ZnO) nanocoating on aligners. METHODS: Twenty-six samples of aligners were sputter-coated with ZnO nanoparticles and compared with 26 uncoated samples. The antimicrobial effect was assessed on Streptococcus mutans and Candida albicans. The thickness of the ZnO coating was standardized at 100 nm. The antimicrobial effect was evaluated for 7 days at the following time points: 6 hours, 12 hours, first day, second day, fourth day, and seventh day. Colony culture tests were performed for microbial evaluation. RESULTS: ZnO-coated aligners showed significant antimicrobial efficacy against S mutans at all time points tested (P <0.001). The antimicrobial effect was observed up to 2 days after a decline. The activity against C albicans was minimal at all time points, and no statistical significance was observed (P >0.05). CONCLUSIONS: ZnO-nanocoated aligners were effective against S mutans, with the maximum antibacterial effect observed until 2 days and lasting for 7 days. The effect against C albicans was minimal. ZnO-coated aligners appears to be a promising technique to facilitate antimicrobial efficacy against S mutans.

A Retrospective Study on Antinuclear Antibody Patterns in Systemic Lupus Erythematosus Patients and Its Correlation With Serological Markers.

INTRODUCTION: Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease. Detection of antinuclear antibodies (ANAs) aids in the diagnosis of SLE. The indirect immunofluorescence (IIF) assay is often used a routine screening test for the detection of ANA. The pathogenic role and significance of various patterns produced in IIF is yet to be explored. AIM: This study aimed to detect ANA patterns generated by IIF and correlate these patterns with specific antibodies detected by line immunoassay. We also investigated the significance of each ANA pattern and its association with specific serological SLE markers, such as complement molecules, anti-dsDNA, antiphospholipid antibody, and C-reactive protein (CRP), along with associations with direct Coombs test (DCT). MATERIALS AND METHODS: We conducted a retrospective study that included 204 patients newly diagnosed with SLE according to the European Alliance of Associations for Rheumatology/American College of Rheumatology (EULAR/ACR) criteria. The detection and pattern determination of ANA was performed by IIF using HEp-20-10. Furthermore, line immunoassay was performed, and the antibody profile of each sample was obtained. Other immunodiagnostic markers were analyzed, including C3, C4, anti-dsDNA, antiphospholipid antibodies (anti-cardiolipin antibodies, anti-beta-2-glycoprotein I, and lupus anticoagulant), CRP, and DCT. RESULTS: Of the 204 samples, the most frequent ANA pattern observed was nucleus speckled (52.9%), followed by nucleus homogenous (27.5%), mixed (13.7%), and cytoplasm speckled (5.9%). The nucleus homogenous pattern showed the most pathogenic immune profile due to its close association with markers of disease activity, namely, high anti-dsDNA titer, low C3 level, and DCT positivity.  Conclusion: This study showed that the most common pattern associated with SLE is nucleus speckled, followed by the nucleus homogenous pattern. Based on associations with specific serological markers, the nucleus homogenous pattern may be linked to a high disease activity in SLE.

Comparison of Streptococcus mutans Adhesion on New and Recycled Metal Brackets: An In Vitro Study.

BACKGROUND: Evaluation of adhesion of Streptococcus mutans on recycled orthodontic brackets is significant, as Streptococcus mutans is the main causative factor in enamel demineralization and many clinicians, in their practice, resort to reconditioning of brackets, as it is cost-effective. Thus, this study aimed to evaluate and compare the adhesion of Streptococcus mutans on new brackets of three different companies (Group I, Group II, and Group III) and brackets recycled by three different recycling methods (RC I: flame heating followed by acid bath; RC II: flame heating followed by ultrasonic cleaning and electropolishing; RC III: flame heating followed by sandblasting and electropolishing). Materials and methods: A total of 10 brackets from each group were incubated with 108 colony-forming units (CFUs) of Streptococcus mutans in trypticase soy broth overnight. The brackets were then washed with phosphate-buffered saline and treated with 0.25% trypsin for 20 minutes followed by vertexing the solution to remove the adhered bacteria and then the solution was plated on the blood agar and incubated overnight. The total viable count of bacteria was quantified. RESULTS: Comparing all the three groups and recycling methods, Group II brackets showed significantly more adhesion, Group I brackets showed lesser adhesion, and Group III brackets showed intermediate adhesion. When comparing recycling methods, all the three methods of recycling with all the three groups showed more bacterial adhesion than the control brackets, which was statistically insignificant (P > 0.05). CONCLUSION: Recycled brackets showed more bacterial adhesion and electropolishing resulted in reduced bacterial adhesion.

Atypical Pneumonia - Screening in a Tertiary Care Centre.

INTRODUCTION: Pneumonia is one of the leading infectious causes of mortality and morbidity worldwide. Atypical respiratory pathogens account for 30 - 40% of these infections. The three most important atypical pathogens are Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella pneumophila. AIM: To screen for atypical pathogens as cause for community acquired pneumonia. MATERIALS AND METHODS: A cross-sectional study was done with 107 patients who had clinical suspicion of atypical pneumonia. The presence of atypical pathogens Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella pneumophila were screened from the patient's sample. Respiratory samples in the form of sputum, Broncheoalveolar lavage and Non- Broncheoalveolar lavage were used for cultivation of Mycoplasma pneumoniae and Legionella pneumophila. Urine specimen was used for the detection of Legionella antigen. Serum samples were used for the detection of Mycoplasma pneumoniae IgM and Chlamydophila pneumoniae IgM antibodies. RESULTS: Among the 107 samples screened, 13(12.1%) were positive for antibodies against atypical pathogens. Out of which 7(6.5%) had IgM antibodies against Mycoplasma pneumoniae and the rest 6(5.6%) had Chlamydophila pneumoniae IgM antibodies. All the samples were culture negative for Mycoplasma pneumoniae and Legionella pneumophila. Urinary antigen detection for Legionella pneumophila was also negative in patients. CONCLUSION: Atypical pathogens should also be considered routinely as a cause of lower respiratory tract infections, especially Chlamydia pneumoniae and Mycoplasma pneumoniae in our country. Serological diagnosis by ELISA can be adopted for determining the infections by atypical pathogens as cultivation is difficult and also requires special media and prolonged incubation. This may not be feasible for many laboratories. Early diagnosis and treatment will reduce the complications.

Evaluation of antimicrobial properties of bioactive glass used in regenerative periodontal therapy.

CONTEXT: Bone grafting materials which have an inherent anti-microbial property against initial colonizers of plaque bacteria would be useful in regenerative periodontal surgical procedures. AIMS: This study was performed to analyze the antibacterial property of a Perioglas™ against a common oral commensal Streptococcus salivarius (early colonizer). SETTINGS AND DESIGN: In vitro observational study. MATERIALS AND METHODS: Perioglas™ (in various concentrations) was assessed for its antibacterial property against the ATCC 13419 strain of S. salivarius. The anti-microbial activity was analyzed in terms of reduction in colony-forming units in culture plates and smear following a 24 h incubation at 37°C. STATISTICAL ANALYSIS USED: Observational study - No statistical analysis applicable. RESULTS: The bioactive glass (BAG) exerted an antibacterial effect against the S. salivarius in the suspending media and smear. The antibacterial activity of BAG increased in proportion with its concentration. CONCLUSIONS: Perioglas™ demonstrated a considerable antibacterial effect against S. salivarius at 50 mg/mL concentration.