Development of a dry powder formulation for pulmonary delivery of azithromycin-loaded nanoparticles.

The COVID-19 pandemic has raised concern regarding respiratory system diseases and oral inhalation stands out as an attractive non-invasive route of administration for pulmonary diseases such as chronic bronchitis, cystic fibrosis, COVID-19 and community-acquired pneumonia. In this context, we encapsulated azithromycin in polycaprolactone nanoparticles functionalized with phospholipids rich in dipalmitoylphosphatidylcholine and further produced a fine powder formulation by spray drying with monohydrated lactose. Nanoparticles obtained by the emulsion/solvent diffusion-evaporation technique exhibited a mean hydrodynamic diameter around 195-228 nm with a narrow monomodal size distribution (PdI < 0.2). Nanoparticle dispersions were spray-dried at different inlet temperatures, atomizing air-flow, aspirator air flow, and feed rate, using lactose as a drying aid, resulting in a maximal process yield of 63% and an encapsulation efficiency of 83%. Excipients and the dry powder formulations were characterized in terms of morphology, chemical structure, thermal analyses and particle size by SEM, FTIR, DSC/TGA and laser light diffraction. The results indicated spherical particles with 90% at 4.06 µm or below, an adequate size for pulmonary delivery. Aerosolization performance in a NGI confirmed good aerodynamic properties. Microbiological assays showed that the formulation preserves AZM antimicrobial effect against Staphylococcus aureus and Streptococcus pneumoniae strains, with halos above 18 mm. In addition, no formulation-related cytotoxicity was observed against the human cell lines BEAS-2B (lung epithelial), HUVEC (endothelial) and HFF1 (fibroblasts). Overall, the approach described here allows the production of AZM-PCL nanoparticles incorporated into inhalable microparticles, enabling more efficient pulmonary therapy of lung infections.

Antibacterial Polysiloxane Polymers and Coatings for Cochlear Implants.

Within this study, new materials were synthesized and characterized based on polysiloxane modified with different ratios of N-acetyl-l-cysteine (NAC) and crosslinked via UV-assisted thiol-ene addition, in order to obtain efficient membranes able to resist bacterial adherence and biofilm formation. These membranes were subjected to in vitro testing for microbial adherence against S. pneumoniae using standardized tests. WISTAR rats were implanted for 4 weeks with crosslinked siloxane samples without and with NAC. A set of physical characterization methods was employed to assess the chemical structure and morphological aspects of the new synthetized materials before and after contact with the microbiological medium.

Antibacterial activity of hinokitiol against both antibiotic-resistant and -susceptible pathogenic bacteria that predominate in the oral cavity and upper airways.

Hinokitiol, a component of the essential oil isolated from Cupressaceae, possesses antibacterial and antifungal activities and has been used in oral care products. In this study, the antibacterial activities of hinokitiol toward various oral, nasal and nasopharyngeal pathogenic bacteria, including Streptococcus mutans, Streptococcus sobrinus, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Fusobacterium nucleatum, methicillin-resistant and -susceptible Staphylococcus aureus, antibiotic-resistant and -susceptible Streptococcus pneumoniae, and Streptococcus pyogenes were examined. Growth of all these bacterial strains was significantly inhibited by hinokitiol, minimal inhibitory concentrations of hinokitiol against S. mutans, S. sobrinus, P. gingivalis, P. intermedia, A. actinomycetemcomitans, F. nucleatum, methicillin-resistant S. aureus, methicillin-susceptible S. aureus, antibiotic-resistant S. pneumoniae isolates, antibiotic-susceptible S. pneumoniae, and S. pyogenes being 0.3, 1.0, 1.0, 30, 0.5, 50, 50, 30, 0.3-1.0, 0.5, and 0.3 µg/mL, respectively. Additionally, with the exception of P. gingivalis, hinokitiol exerted bactericidal effects against all bacterial strains 1 hr after exposure. Hinokitiol did not display any significant cytotoxicity toward the human gingival epithelial cell line Ca9-22, pharyngeal epithelial cell line Detroit 562, human umbilical vein endothelial cells, or human gingival fibroblasts, with the exception of treatment with 500 µg/mL hinokitiol, which decreased numbers of viable Ca9-22 cells and gingival fibroblasts by 13% and 12%, respectively. These results suggest that hinokitiol exhibits antibacterial activity against a broad spectrum of pathogenic bacteria and has low cytotoxicity towards human epithelial cells.

Optimization of a dry powder inhaler of ciprofloxacin-loaded polymeric nanomicelles by spray drying process.

Ciprofloxacin is a commonly prescribed antibiotic for treatment of pulmonary infections. Nanocarriers such as nanomicelles can increase the drug residence time in the lungs and enhance their antibacterial effects. Dry powder inhalers (DPIs) are the preferred pulmonary drug delivery system and preparation of an optimum nanoaggregate from nanomicelles by means of spray drying would be valuable. The two-level full factorial design was performed in 16 runs. The effects of carrier type, anti-adhesion agent type, carrier to nanoparticle ratio and anti-adhesion agent to carrier ratio on the size of the microparticles, their in vitro pulmonary deposition, and redispersibility were investigated. Its antibacterial effects against Pseudomonas aeruginosa, Klebsiella pneumoniae, and Streptococcus pneumoniae also were investigated. All independent variables were fitted into two-factorial interaction models. The optimum nanoaggregate was prepared using mannitol and L-phenylalanine with a D0.5 of 1.7 µm and 60% fine particles. The process had no negative effect on the stability or drug release profile of the nanomicelles. The antibacterial effects of ciprofloxacin against microorganisms increased significantly. This spray drying process could be used for preparation of an optimum DPI from polymeric nanomicelles. This formulation could increase the efficacy of ciprofloxacin for treatment of pulmonary infections.

Enzyme-mediated formulation of stable elliptical silver nanoparticles tested against clinical pathogens and MDR bacteria and development of antimicrobial surgical thread.

BACKGROUND: Silver nanoparticles (AgNPs) are believed to be emerging tool against various infectious diseases including multi-drug resistant (MDR) bacteria. In the present study, in vitro synthesis of AgNPs was optimized using 1:50 ratio of macerozyme (25 µg/µl) and 1 mM AgNO3 incubated at 80 °C for 8 h. AgNPs were characterized by UV-Visible spectroscopy, dynamic light scattering (DLS), scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD). RESULTS: Characterization studies suggest the synthesis of elliptical, stable and crystalline AgNPs with an average size of 38.26 ± 0.4 nm calculated using TEM. The XRD pattern revealed the face-centered-cubic (fcc) form of metallic silver. Good shape integrity and dispersion of AgNPs after 1 year of incubation confirmed their stability. AgNPs were exibited the antimicrobial property against ten pathogenic bacteria, three molds and one yeast. The AgNPs also revealed remarkable antimicrobial activity against three MDR strains i.e. Extended spectrum beta-lactamase positive Escherichia coli, Staphylococcus aureus (MRSA) and Teicoplanin resistant Streptococcus Pneumoniae. The AgNPs coated surgical threads (suture) were revealed the remarkble antibacterial activity against three MDR strains. This is the first report to synthesize antimicrobial elliptical AgNPs using enzymes. CONCLUSION: The results suggest the possibilities to develop the nanoparticles coated antimicrobial medical fabric to combat against MDR infection.

Morin Moderates the Biotoxicity of Pneumococcal Pneumolysin by Weakening the Oligomers' Formation.

Streptococcus pneumoniae (pneumococcus) is an important causative agent of acute invasive and non-invasive infections. Pneumolysin is one of a considerable number of virulence traits produced by pneumococcus that exhibits a variety of biological activities, thus making it a target of small molecule drug development. In this study, we aimed to evaluate the effect of morin, a natural compound that has no antimicrobial activity against S. pneumonia, is a potent neutralizer of pneumolysin-mediated cytotoxicity and genotoxicity by impairing oligomer formation, and possesses the capability of mitigating tissue damage caused by pneumococcus. These findings indicate that morin could be a potent candidate for a novel therapeutic or auxiliary substance to treat infections for which there are inadequate vaccines and that are resistant to traditional antibiotics.

Different Behavior and Response of Staphylococcus Epidermidis and Streptococcus Pneumoniae to a Ventriculoperitoneal Shunt: An in vitro Study.

BACKGROUND: Pneumococcal shunt infection is a rare event. There is no consensus on the therapeutic management of this kind of shunt infection according to literature reviews, and it seems to be different from infection with Staphylococcus epidermidis. We studied 2 shunted patients with pneumococcal meningitis, both of whom were treated with only antibiotics. The management of these cases seems to be different from that of shunt catheter infection due to these bacteria. We conducted a laboratory study to show the different behavior of pneumococcus compared to S. epidermidis regarding shunt catheter colonization. MATERIALS AND METHODS: S. epidermidis and Streptococcus pneumoniae bacteria isolated from the cerebrospinal fluid of meningitis patients were incubated in sterile media. Forty-five segments of shunt catheter from silicone material were placed in 45 separate media of S. epidermidis and pneumococcus. Then each catheter was washed and cultured in blood chocolate agar growth medium in separate petri dishes via the roll plate method. The dishes were extracted from the incubator and the colony count was calculated after 72 h. RESULTS: The colony count was obviously different between the 2 bacteria groups, with a higher count related to S. epidermidis dishes. The colony count of the pneumococcal petri dishes was 25-35,000 (mean 14,337) and for dishes with S. epidermidis it was 14,000-100,000 (mean 50,125) (p = 0.001). CONCLUSION: The adherence of pneumococcus to shunt catheters seems to be much less than that of S. epidermidis, which produced a very low colony count when incubated with the catheter in the medium culture. S. pneumoniae meningitis in shunted patients can be managed successfully with only antibiotics. This approach can prevent problems related to the several additional surgeries required for shunt removal, a new shunt insertion, and the management of high intracranial pressure.

Inhaled antibiotics: A promising drug delivery strategies for efficient treatment of lower respiratory tract infections (LRTIs) associated with antibiotic resistant biofilm-dwelling and intracellular bacterial pathogens.

Antibiotic-resistant bacteria associated with LRTIs are frequently associated with inefficient treatment outcomes. Antibiotic-resistant Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas aeruginosa, and Staphylococcus aureus, infections are strongly associated with pulmonary exacerbations and require frequent hospital admissions, usually following failed management in the community. These bacteria are difficult to treat as they demonstrate multiple adaptational mechanisms including biofilm formation to resist antibiotic threats. Currently, many patients with the genetic disease cystic fibrosis (CF), non-CF bronchiectasis (NCFB) and chronic obstructive pulmonary disease (COPD) experience exacerbations of their lung disease and require high doses of systemically administered antibiotics to achieve meaningful clinical effects, but even with high systemic doses penetration of antibiotic into the site of infection within the lung is suboptimal. Pulmonary drug delivery technology that reliably deliver antibacterials directly into the infected cells of the lungs and penetrate bacterial biofilms to provide therapeutic doses with a greatly reduced risk of systemic adverse effects. Inhaled liposomal-packaged antibiotic with biofilm-dissolving drugs offer the opportunity for targeted, and highly effective antibacterial therapeutics in the lungs. Although the challenges with development of some inhaled antibiotics and their clinicals trials have been studied; however, only few inhaled products are available on market. This review addresses the current treatment challenges of antibiotic-resistant bacteria in the lung with some clinical outcomes and provides future directions with innovative ideas on new inhaled formulations and delivery technology that promise enhanced killing of antibiotic-resistant biofilm-dwelling bacteria.

Study on the effect of chlorogenic acid on the antimicrobial effect, physical properties and model accuracy of alginate impression materials.

Background: Dental impressions are essential for accurately capturing the detailed anatomy of teeth and surrounding oral structures. However, these impressions often become contaminated with saliva and blood, making proper disinfection necessary. The application of chemical disinfectants has been associated with negative side effects, leading to suboptimal disinfection practices in clinical settings. Objective: The purpose of this study was to evaluate the effectiveness of chlorogenic acid (CA) as a disinfectant for alginate impression materials, the impact of CA disinfection on the physical properties and dimensional accuracy of alginate impressions was also investigated. Methods: The physical properties of alginate impression materials, such as elastic recovery, strain-in-compression, initial setting time, and fluidity, were assessed after mixing the alginate impression materials with three different concentrations of CA solution (10 mg/mL, 15 mg/mL, 20 mg/mL). To evaluate the antimicrobial effect of CA, alginate impressions mixed with a 10 mg/mL CA solution and impressions mixed with distilled water (control group) were contaminated with four types of microorganism: Escherichia coli, Staphylococcus aureus, Candida albicans, and Streptococcus pneumoniae. Following a five-minute incubation period, a CA solution at a concentration of either 50 mg/mL, 55 mg/mL, or 60 mg/mL was sprayed on the samples for disinfection. Samples were collected at different time intervals (10 min, 20 min, 30 min) and cultured to determine the number of colony-forming units (CFU/mL), providing insight into the antimicrobial efficacy of these CA solutions. The dimensional accuracy of alginate impressions was assessed in three groups: one with alginate impressions mixed with distilled water, another with alginate impressions sterilized with available chlorine (2,000 mg/L) mixed with distilled water, and the last group consisting of alginate impressions mixed with 10 mg/mL CA solution and sprayed with 60 mg/mL CA solution. Both the standard model and the plaster model underwent 3D scanning, and the data were processed and compared by software. The root mean square (RMS) was used as a parameter to evaluate the deviation between models. Results: All alginate impression materials mixed with either 10 mg/mL, 15 mg/mL, or 20 mg/mL concentrations of CA solution met the ISO 21563 standard for elastic recovery, strain-in-compression, and fluidity. However, only the material mixed with a concentration of 10 mg/mL CA had an initial setting time within the range specified by the T-6505 Japanese industrial standard. The application of CA solution by mixing or spraying showed significant antimicrobial effects on Staphylococcus aureus, Escherichia coli, Candida albicans, and Streptococcus pneumoniae. There was no significant difference in the dimensional accuracy of the alginate impressions between the group of the CA solution applied, the blank group, or the chlorine intervention group.

Nanogel-based PspA intranasal vaccine prevents invasive disease and nasal colonization by Streptococcus pneumoniae.

To establish a safer and more effective vaccine against pneumococcal respiratory infections, current knowledge regarding the antigens common among pneumococcal strains and improvements to the system for delivering these antigens across the mucosal barrier must be integrated. We developed a pneumococcal vaccine that combines the advantages of pneumococcal surface protein A (PspA) with a nontoxic intranasal vaccine delivery system based on a nanometer-sized hydrogel (nanogel) consisting of a cationic cholesteryl group-bearing pullulan (cCHP). The efficacy of the nanogel-based PspA nasal vaccine (cCHP-PspA) was tested in murine pneumococcal airway infection models. Intranasal vaccination with cCHP-PspA provided protective immunity against lethal challenge with Streptococcus pneumoniae Xen10, reduced colonization and invasion by bacteria in the upper and lower respiratory tracts, and induced systemic and nasal mucosal Th17 responses, high levels of PspA-specific serum immunoglobulin G (IgG), and nasal and bronchial IgA antibody responses. Moreover, there was no sign of PspA delivery by nanogel to either the olfactory bulbs or the central nervous system after intranasal administration. These results demonstrate the effectiveness and safety of the nanogel-based PspA nasal vaccine system as a universal mucosal vaccine against pneumococcal respiratory infection.

Comparison of the antibacterial effects of matrica & Persica™ and chlorhexidine gluconate mouthwashes in mechanically ventilated ICU patients: a double blind randomized clinical trial.

BACKGROUND: Accumulation of bacteria in the pharynx is one of the risk factors of pneumonia due to ventilation. One of the methods of prevention from accumulation of bacteria in the pharynx is the use of oral solutions. Chlorhexidine is considered as the gold standard, but it has various side effects. AIM: Present study was aimed to determine and compare anti-bacterial effects of the chlorhexidine gluconate 0.2%, herbal mouthwash of Matrica® (chamomile extracts) 10%, PersicaTM 10% and normal saline in intensive care unit patients. METHODS: In this double blind randomized clinical trial, 80 patients who were admitted in ICU divided into four groups of 20 patients each one. Researchers applied PersicaTM to group one, chlorhexidine gluconate mouth wash 0.2% to group two and third group received Matrica, finally in the control group, normal saline were used. In order to culturing of Staphylococcus aureus and S. pneumoniae,salivary samples were obtained without any stimulation after six minimums oral rinsing. The data were processed in SPSS17 software and analyzed by appropriate statistical tests. RESULTS: Decreased rate of bacterial colonies after intervention in the whole four groups was significant (p < 0.001). The mouth wash of chlorhexidine (p < 0.001), PersicaTM (p: 0.008) and Matrica (p: 0.01) had a significant antibacterial effect on S. aureus and S. pneumoniae(p < 0.001). CONCLUSION: Herbal oral mouthwash of persica and matrica has the effect on S. pneumoniae and S. aureus of oropharynx area in mechanically ventilated patients. However, there is a need for further research to be considered as an alternative to chlorhexidine for prevention of VALP in ICU patients.

Capsular typing of Streptococcus pneumoniae isolated from clinical specimens in Gauhati Medical College and hospital, Assam, India.

PURPOSE: Streptococcus pneumoniae is an important human respiratory tract pathogen causing pneumococcal diseases in majority of children and adults. The capsule is a significant virulence factor of Pneumococci which determines the bacterial serotype and is the component used for synthesis of pneumococcal vaccines. This cross-sectional study aimed to isolate Streptococcus pneumoniae from clinical samples and determine the occurrence of its circulating serotypes in Assam, North East India. MATERIALS AND METHODS: A total of 80 clinical samples were collected from June 2019 to May 2020 from patients clinically suspected from pneumococcal infection and also included samples routinely sent to bacteriology laboratory. Isolation and identification of S. pneumoniae was performed using conventional culture and molecular methods. Antibiotic susceptibility patterns were monitored. Capsular serotyping was performed using PCR of cpsA gene followed by DNA sequencing. RESULTS: Majority of the cases suspected of pneumococcal infection belong to the paediatric group aged less than 5 years. Out of 80 samples, 10 (12.50%) were found to be positive by PCR of recP gene. Culture was positive in 80% (8/10) of the total positives. Co-trimoxazole resistance was seen in 33.33% of the isolate from sputum. Serotypes 6A, 6B, 6C and 19F were detected in our region, out of which 6C is a non-vaccine serotype. CONCLUSION: Continued surveillance is needed to monitor trends in non-vaccine serotypes that may emerge as highly associated with antibiotic resistance. Also, the need to continuous monitoring of the antibiotic susceptibility of S. pneumoniae in North eastern parts of India is of outmost importance.

Antibacterial activity of clarithromycin loaded PLGA nanoparticles.

Novel drug delivery systems such as nanoparticles (NPs) have been proved to enhance the effectiveness of many drugs. Clarithromycin is a broad spectrum macrolide antibiotic, used in many infectious conditions like upper and lower respiratory tract infections, and skin and other soft tissue infections. This paper describes the preparation and enhanced in vitro antibacterial activities of clarithromycin loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles. A modified quasi-emulsion solvent diffusion (MQESD) method was used to prepare clarithromycin (CLR) NPs. The antibacterial activity of the NPs was evaluated using the agar well diffusion method against Escherichia coli (PTCC 1330), Haemophilus influenzae (PTCC 1623), Salmonella typhi (PTCC 1609), Staphylococcus aureus (PTCC 1112) and Streptococcus pneumoniae (PTCC 1240). The inhibition zone diameters related to each nano formulation were compared with those for untreated CLR at the same concentrations. The results indicated that the mean inhibition zone diameters of NPs against all the bacteria tested were significantly higher than those of untreated CLR, particularly in the case of S. aureus. The increased potency of CLR NPs may be related to some physicochemical properties of NPs like modified surface characteristics, lower drug degradation, and increased drug adsorption and uptake.

Effect of saliva viscosity on the co-aggregation between oral streptococci and Actinomyces naeslundii.

BACKGROUND: The co-aggregation of oral bacteria leads to their clearance from the oral cavity. Poor oral hygiene and high saliva viscosity are common amongst the elderly; thus, they frequently suffer from pneumonia caused by the aspiration of oral microorganisms. OBJECTIVES: To examine the direct effect of saliva viscosity on the co-aggregation of oral streptococci with actinomyces. MATERIALS AND METHODS: Fifteen oral streptococcal and a single actinomyces strain were used. Co-aggregation was assessed by a visual assay in phosphate buffer and a spectrophotometric assay in the same buffer containing 0-60% glycerol or whole saliva. RESULTS: Nine oral streptococci co-aggregated with Actinomyces naeslundii ATCC12104 in the visual assay and were subsequently used for the spectrophotometric analysis. All tested strains displayed a decrease in co-aggregation with increasing amounts of glycerol in the buffer. The co-aggregation of Streptococcus oralis with A. naeslundii recovered to baseline level following the removal of glycerol. The per cent co-aggregation of S. oralis with A. naeslundii was significantly correlated with the viscosity in unstimulated and stimulated whole saliva samples (correlation coefficients: -0.52 and -0.48, respectively). CONCLUSION: This study suggests that saliva viscosity affects the co-aggregation of oral streptococci with actinomyces and that bacterial co-aggregation decreases with increasing saliva viscosity.

Comparison of antibacterial effects of oral rinses chlorhexidine and herbal mouth wash in patients admitted to intensive care unit.

BACKGROUND AND PURPOSE: Mouthwashes decrease the risk of VAP by reducing the number of microorganisms and their transmission and colonization in the lung. Among the oral rinses, chlorhexidine is considered as the gold standard but it has a variety of complications. The purpose of this study was to determine and compare anti-bacterial effects of the chlorhexidine gluconate and herbal mouthwashes in intensive care unit patients. MATERIALS AND METHODS: In this double blind randomized clinical trial, 60 patients who were admitted in ICU were divided into two equal 30 persons groups. In the first group Chlorhexidine gluconate 2 % mouthwash and in the second group herbal mouth wash was used. Just before and again after 6 min of oral rinsing, salivary samples were obtained without any stimulation in order to culture Staphylococcus aureus and Streptococcus pneumoniae. The data were processed in SPSS16 software and were analyzed by appropriate statistical tests. RESULTS: Matrica® and chlorhexidine mouthwashes have significant antibacterial effects against Streptococcus pneumoniae and Staphylococcus aureus. Decreasing of the number of bacteria in samples after oral rinsing was significant in both groups (p <0.001) but chlorhexidine was significantly more effective than herbal mouth wash in reducing the number of colonies (p < 0.001). CONCLUSION: The herbal mouth wash has significant antibacterial effects against Staphylococcus aureus and Streptococcus pneumoniae, but its efficacy is less than chlorhexidine, so after further investigation, it would be considered as an alternative to chlorhexidine in ICUs (Tab. 3, Ref. 33).

Decrease in penicillin susceptibility due to heat shock protein ClpL in Streptococcus pneumoniae.

Antibiotic resistance and tolerance are increasing threats to global health as antibiotic-resistant bacteria can cause severe morbidity and mortality and can increase treatment cost 10-fold. Although several genes contributing to antibiotic tolerance among pneumococci have been identified, we report here that ClpL, a major heat shock protein, could modulate cell wall biosynthetic enzymes and lead to decreased penicillin susceptibility. On capsular type 1, 2, and 19 genetic backgrounds, mutants lacking ClpL were more susceptible to penicillin and had thinner cell walls than the parental strains, whereas a ClpL-overexpressing strain showed a higher resistance to penicillin and a thicker cell wall. Although exposure of Streptococcus pneumoniae D39 to penicillin inhibited expression of the major cell wall synthesis gene pbp2x, heat shock induced a ClpL-dependent increase in the mRNA levels and protein synthesized by pbp2x. Inducible ClpL expression correlated with PBP2x expression and penicillin susceptibility. Fractionation and electron micrograph data revealed that ClpL induced by heat shock is localized at the cell wall, and the ΔclpL showed significantly reduced net translocation of PBP2x into the cell wall. Moreover, coimmunoprecipitation with either ClpL or PBP2x antibody followed by reprobing with ClpL or PBP2x antibody showed an interaction between ClpL and PBP2x after heat stress. This interaction was confirmed by His tag pulldown assay with either ClpLHis6 or PBP2xHis6. Thus, ClpL stabilized pbp2x expression, interacted with PBP2x, and facilitated translocation of PBP2x, a key protein of cell wall synthesis process, contributing to the decrease of antibiotic susceptibility in S. pneumoniae.

Pharmacological characterization of a structurally new class of antibacterial compound, triphenyl-phosphonium conjugated diarylheptanoid: Antibacterial activity and molecular mechanism.

Many pathogenic species of bacteria are showing increasing drug resistance against clinically used antibiotics. Molecules structurally distant from known antibiotics and possessing membrane targeting bactericidal activities are more likely to display activity against drug-resistant pathogens. Mitocurcumin (MitoC) is one of such compounds, synthesized by triphenyl-phosphonium conjugation with curcumin, and has been shown recently from our laboratory to have broad-spectrum bactericidal activity (Kumari et al. 2019 Free Radic. Biol. Med. 143, 140-145). Here, we further demonstrate the antibacterial properties of MitoC against resistant strains and also its mechanism of action. It displays efficient bactericidal activity against multidrug-resistant Staphylococcus aureus and Streptococcus pneumoniae (MIC values in the 1.5-12.5 µM range), and coagulase-negative Staphylococci do not show resistance development against MitoC. Liposome based studies and MIC values against TolC deletion mutant (Δ tolC; outer membrane protein) of E. coli suggest extensive membrane damage to be the primary mechanism of bactericidal activity. MitoC did not exhibit toxicity in BALB/c mice with an oral administration of 250 mg/kg body weight and was found to be totally safe without any significant effect on haematological, biochemical parameters and inflammatory responses. Its rapid bactericidal action as assessed by in vitro time-kill assay against B. subtilis, compared to ciprofloxacin, and long half-life in rodent serum, suggest that MitoC could be an excellent lead-molecule against drug-resistant pathogens. The highlights of the study are that mitocurcumin belongs to a structurally new class of bactericidal compounds. It displays activity against MDR strains of pathogenic bacteria and challenging MRSA. Liposome-based studies confirm the membrane damaging property of the molecule. Mitocurcumin does not show resistance development even after 27 bacterial generations.

Effects of Diluents, Saliva and Other Organics on the Microbicidal Activity of Cetylpyridinium Chloride and Povidone-iodine.

Povidone-iodine (PVP-I) is used for infection control and preoperative sterilization of the oral and pharyngeal regions. Marketed preparations containing cetylpyridinium chloride (CPC) are used to inhibit growth of oral bacteria. We conducted an in vitro study of the sterilizing effects of these microbicides on 10 oral bacterial strains and fungi related to pneumonia and periodontal disease, after dilution with phosphate-buffered saline (PBS), saliva, and components in saliva. The CPC solution was evaluated at 50 mg/100 mL, which is the concentration used in products. CPC sterilized all strains within 1 minute. Prolongation of the sterilization time associated with dilution was more gradual in comparison to PVP-I solution. CPC sterilized 7 of 10 microbial strains within 3 minutes at 3 mg/100 mL. At 500 mg/100 mL, which is near the upper limit of the concentration that is actually used, PVP-I solution sterilized 7 microbial strains within 3 minutes. However, PVP-I had no sterilization effect when diluted to 100 mg/100 mL or lower. With addition of saliva, PVP-I sterilized 2 microbial strains within 3 minutes at 500 mg/100 mL, whereas CPC solution sterilized 9 microbial strains within 1 minute at 50 mg/100 mL. Our results show that in use influenced by dilution with saliva, CPC is likely to maintain a strong sterilization effect, whereas PVP-I may have a reduced effect.

Newly defined in vitro quality control ranges for oritavancin broth microdilution testing and impact of variation in testing parameters.

A 9-laboratory M23-A2 quality control (QC) study was performed to evaluate reproducibility of oritavancin MICs against reference strains of Staphylococcus aureus, Enterococcus faecalis, and Streptococcus pneumoniae using broth microdilution assays in the presence of polysorbate 80. Polysorbate 80 has previously been shown to be required for accurate measurement of oritavancin broth microdilution MICs. Greater than 95% of replicate results (n = 270/organism) fell within the following QC ranges (in micrograms per milliliter): S. aureus ATCC 29213, 0.015 to 0.12; E. faecalis ATCC 29212, 0.008 to 0.03; and S. pneumoniae ATCC 49619, 0.001 to 0.004. Oritavancin MIC QC ranges were, thus, narrow and reproducible. Parameters affecting testing results in the presence of polysorbate 80 were also evaluated. Oritavancin MICs were equivalent to or within 1 doubling dilution of those obtained under standard Clinical and Laboratory Standards Institute testing conditions, regardless of incubation time (18, 24, or 48 h), Ca(2+) concentration, pH, or frozen panel storage time (up to 6 months).

Prevention and treatment of penicillin-resistant Streptococcus pneumoniae meningitis after intracraniofacial surgery with distraction osteogenesis.

The prevalence of penicillin-resistant Streptococcus pneumoniae (PRSP) meningitis has increased worldwide, particularly in East Asia and the United States. We recently experienced a case of PRSP meningitis that developed during frontofacial distraction. The patient was a 7-year-old girl with Crouzon disease who was treated by frontofacial monobloc/Le Fort IV minus glabellar osteotomy with quadruple internal distraction devices. Penicillin-resistant Streptococcus pneumoniae meningitis was diagnosed after surgery and treated successfully with meropenem (a carbapenem) at 120 mg kg d every 8 hours, ceftriaxone (a third-generation cephalosporin) at 100 mg kg d every 12 hours, and vancomycin (a glycopeptide) at 45 mg kg d every 6 hours. This case indicates that severe and fatal bacterial meningitis may occur as a postoperative complication due to multidrug-resistant bacteria indigenous to the nasal cavity after simultaneous osteotomy of the cranium and facial bone in intracraniofacial surgery, such as that for syndromic craniosynostosis and hypertelorbitism. In such cases, preventive strategies should include preoperative administration of pneumococcal vaccine, preoperative screening of nasal bacterial flora by nasal culture test, and prior administration of a carbapenem with good cerebrospinal fluid transfer or a third- or fourth-generation cephem covering PRSP. Postoperatively, suspected meningitis may be treated with a combination of the 3 drugs used in our case, in parallel with emergency cephalic contrast computed tomography and culture tests of blood and cerebrospinal fluid. Our experience suggests that these measures will facilitate a successful outcome in frontofacial distraction osteogenesis.