Injectable Chitosan-Methoxy Polyethylene Glycol Hybrid Hydrogel Untangling the Wound Healing Behavior: In Vitro and In Vivo Evaluation.

Wound healing, particularly for difficult-to-treat wounds, presents a serious threat and may lead to complications. Currently available dressings lack mucoadhesion, safety, efficacy, and, most importantly, patient compliance. Herein, we developed a unique, simple, and inexpensive injectable chitosan-methoxy polyethylene glycol (chitosan-mPEG) hybrid hydrogel with tunable physicochemical and mechanical properties for wound healing. The detailed physicochemical and rheological characterization of the chitosan-mPEG hydrogel has revealed chemical interaction between available -NH2 groups of chitosan and -COOH groups of mPEG acid, which, to our perspective, enhanced the mechanical and wound healing properties of hybrid chitosan and mPEG hydrogel compared to solo chitosan or PEG hydrogel. By introducing mPEG, the wound healing ability of hydrogel is synergistically improved due to its antibacterial feature, together with chitosan's innate role in hemostasis and wound closure. The detailed hemostasis and wound closure potential of the chitosan-mPEG hydrogel were investigated in a rat model, which confirmed a significant acceleration in wound healing and ultimately wound closure. In conclusion, the developed chitosan-mPEG hydrogel met all the required specifications and could be developed as a promising material for hemostasis, especially wound management, and as an excellent candidate for wound healing application.

Colony phase variation switch modulates antimicrobial tolerance and biofilm formation in Acinetobacter baumannii.

Carbapenem-resistant Acinetobacter baumannii causes one of the most difficult-to-treat nosocomial infections. Polycationic drugs like polymyxin B or colistin and tetracycline drugs such as doxycycline or minocycline are commonly used to treat infections caused by carbapenem-resistant A. baumannii. Here, we show that a subpopulation of cells associated with the opaque/translucent colony phase variation by A. baumannii AB5075 displays differential tolerance to subinhibitory concentrations of colistin and tetracycline. Using a variety of microscopic techniques, we demonstrate that extracellular polysaccharide moieties mediate colistin tolerance to opaque A. baumannii at single-cell level and that mushroom-shaped biofilm structures protect opaque bacteria at the community level. The colony switch phenotype is found to alter several traits of A. baumannii, including long-term survival under desiccation, tolerance to ethanol, competition with Escherichia coli, and intracellular survival in the environmental model host Acanthamoeba castellanii. Additionally, our findings suggest that extracellular DNA associated with membrane vesicles can promote colony switching in a DNA recombinase-dependent manner.IMPORTANCEAs a WHO top-priority drug-resistant microbe, Acinetobacter baumannii significantly contributes to hospital-associated infections worldwide. One particularly intriguing aspect is its ability to reversibly switch its colony morphotype on agar plates, which has been remarkably underexplored. In this study, we employed various microscopic techniques and phenotypic assays to investigate the colony phase variation switch under different clinically and environmentally relevant conditions. Our findings reveal that the presence of a poly N-acetylglucosamine-positive extracellular matrix layer contributes to the protection of bacteria from the bactericidal effects of colistin. Furthermore, we provide intriguing insights into the multicellular lifestyle of A. baumannii, specifically in the context of colony switch variation within its predatory host, Acanthamoeba castellanii.

Csu pili dependent biofilm formation and virulence of Acinetobacter baumannii.

Acinetobacter baumannii has emerged as one of the most common extensive drug-resistant nosocomial bacterial pathogens. Not only can the bacteria survive in hospital settings for long periods, but they are also able to resist adverse conditions. However, underlying regulatory mechanisms that allow A. baumannii to cope with these conditions and mediate its virulence are poorly understood. Here, we show that bi-stable expression of the Csu pili, along with the production of poly-N-acetyl glucosamine, regulates the formation of Mountain-like biofilm-patches on glass surfaces to protect bacteria from the bactericidal effect of colistin. Csu pilus assembly is found to be an essential component of mature biofilms formed on glass surfaces and of pellicles. By using several microscopic techniques, we show that clinical isolates of A. baumannii carrying abundant Csu pili mediate adherence to epithelial cells. In addition, Csu pili suppressed surface-associated motility but enhanced colonization of bacteria into the lungs, spleen, and liver in a mouse model of systemic infection. The screening of c-di-GMP metabolizing protein mutants of A. baumannii 17978 for the capability to adhere to epithelial cells led us to identify GGDEF/EAL protein AIS_2337, here denoted PdeB, as a major regulator of Csu pili-mediated virulence and biofilm formation. Moreover, PdeB was found to be involved in the type IV pili-regulated robustness of surface-associated motility. Our findings suggest that the Csu pilus is not only a functional component of mature A. baumannii biofilms but also a major virulence factor promoting the initiation of disease progression by mediating bacterial adherence to epithelial cells.

Antimicrobial drug resistant features of Mycobacterium tuberculosis associated with treatment failure.

Tuberculosis stands as a prominent cause of mortality in developing countries. The treatment of tuberculosis involves a complex procedure requiring the administration of a panel of at least four antimicrobial drugs for the duration of six months. The occurrence of treatment failure after the completion of a standard treatment course presents a serious medical problem. The purpose of this study was to evaluate antimicrobial drug resistant features of Mycobacterium tuberculosis associated with treatment failure. Additionally, it aimed to evaluate the effectiveness of second line drugs such as amikacin, linezolid, moxifloxacin, and the efflux pump inhibitor verapamil against M. tuberculosis isolates associated with treatment failure. We monitored 1200 tuberculosis patients who visited TB centres in Lahore and found that 64 of them were not cured after six months of treatment. Among the M. tuberculosis isolates recovered from the sputum of these 64 patients, 46 (71.9%) isolates were simultaneously resistant to rifampicin and isoniazid (MDR), and 30 (46.9%) isolates were resistant to pyrazinamide, Resistance to amikacin was detected in 17 (26,5%) isolates whereas resistance to moxifloxacin and linezolid was detected in 1 (1.5%) and 2 (3.1%) isolates respectively. Among MDR isolates, the additional resistance to pyrazinamide, amikacin, and linezolid was detected in 15(23.4%), 4(2.6%) and 1(1.56%) isolates respectively. One isolate simultaneously resistant to rifampicin, isoniazid, amikacin, pyrazinamide, and linezolid was also identified. In our investigations, the most frequently mutated amino acid in the treatment failure group was Serine 315 in katG. Three novel mutations were detected at codons 99, 149 and 154 in pncA which were associated with pyrazinamide resistance. The effect of verapamil on the minimum inhibitory concentration of isoniazid and rifampicin was observed in drug susceptible isolates but not in drug resistant isolates. Rifampicin and isoniazid enhanced the transcription of the efflux pump gene rv1258 in drug susceptible isolates collected from the treatment failure patients. Our findings emphasize a high prevalence of MDR isolates linked primarily to drug exposure. Moreover, the use of amikacin as a second line drug may not be the most suitable choice in such cases.

Emergence of high colistin resistance in carbapenem resistant Acinetobacter baumannii in Pakistan and its potential management through immunomodulatory effect of an extract from Saussurea lappa.

Carbapenem resistant Acinetobacter baumannii has emerged as one of the most difficult to treat nosocomial bacterial infections in recent years. It was one of the major causes of secondary infections in Covid-19 patients in developing countries. The polycationic polypeptide antibiotic colistin is used as a last resort drug to treat carbapenem resistant A. baumannii infections. Therefore, resistance to colistin is considered as a serious medical threat. The purpose of this study was to assess the current status of colistin resistance in Pakistan, a country where carbapenem resistant A. bumannii infections are endemic, to understand the impact of colistin resistance on virulence in mice and to assess alternative strategies to treat such infections. Out of 150 isolates collected from five hospitals in Pakistan during 2019-20, 84% were carbapenem resistant and 7.3% were additionally resistant to colistin. There were two isolates resistant to all tested antibiotics and 83% of colistin resistant isolates were susceptible to only tetracycline family drugs doxycycline and minocycline. Doxycycline exhibited a synergetic bactericidal effect with colistin even in colistin resistant isolates. Exposure of A. baumannii 17978 to sub inhibitory concentrations of colistin identified novel point mutations associated with colistin resistance. Colistin tolerance acquired independent of mutations in lpxA, lpxB, lpxC, lpxD, and pmrAB supressed the proinflammatory immune response in epithelial cells and the virulence in a mouse infection model. Moreover, the oral administration of water extract of Saussuria lappa, although not showing antimicrobial activity against A. baumannii in vitro, lowered the number of colonizing bacteria in liver, spleen and lung of the mouse model and also lowered the levels of neutrophils and interleukin 8 in mice. Our findings suggest that the S. lappa extract exhibits an immunomodulatory effect with potential to reduce and cure systemic infections by both opaque and translucent colony variants of A. baumannii.

Restructuring emergency eye services during COVID-19 in a tertiary referral centre.

BACKGROUND/AIMS: Maintaining emergency eye services is crucial during the COVID-19 pandemic. This article describes the introduction of a new restructured referral pathway to reduce the burden on healthcare providers and create a safe environment. METHODS: During January and February 2020 (group 1), all appointments were face-to-face with a walk-in eye casualty. The first audit cycle comprised all patients in group 1. The primary audit criteria were discharge rates, referral to subspeciality and reattendance. In April 2020, a remodelled system was implemented in which walk-in attendance ceased and was replaced with telephone triage coupled with digital imaging via NHS email for remote clinical review. Patients requiring further assessment following this triage were invited in for face-to-face appointments. A reaudit was conducted during April-July 2020 (group 2) following implementation of these COVID-19 protocol changes. RESULTS: In group 1, 2868 appointments (100.0%) were face-to-face and in group 2 4870 (100.0%) appointments were telephone consults that resulted in 2639 (54.2%) face-to-face appointments. The rate of discharge in the first cycle and second cycle were 55.3% and 76.9% respectively (P<0.0001). Furthermore 2298 (47.2%) patients were able to be discharged following telephone consultation in group 2. CONCLUSIONS: Using this telephone and digital imaging review triage system, the authors have demonstrated a significant reduction in the need for face-to-face reviews. The reduction in avoidable patient face-to-face reviews allows the system to move from saturated to sustainable while increasing accessibility to services for patients who may not be able to present for face-to-face review. This complete audit cycle successfully charts interventions that maximise accessibility, reduce unnecessary hospital visits and deliver safe and prompt management during the pandemic.

Chronic tarsal conjunctivitis.

BACKGROUND: Toxicity is rarely considered in the differential diagnosis of conjunctivitis, but we present here a new form of toxic conjunctivitis with unusual clinical features. Between 2010 and 2013, a new clinical presentation of chronic conjunctivitis unresponsive to normal treatment was noted within a Primary Care Ophthalmology Service. METHODS: Retrospective review of case records and histopathology results. RESULTS: A total of 55 adult patients, all females, presented with epiphora and stickiness. They did not complain of itch and had had symptoms for an average of 9 months. Clinical examination showed bilateral moderate to severe upper and lower tarsal conjunctival papillary reaction, without corneal or eyelid changes and mild bulbar conjunctival hyperaemia in a third of cases. Biopsies were taken in 15 cases to exclude an atypical infection or lymphoma. Histologically, there was a variable superficial stromal lymphocytic infiltrate, involving the epithelium in more severe cases. The majority of the cells were CD3 positive T-lymphocytes and follicle formation was not noted. The clinical history in all cases included prolonged use of eye make- up and other facial cosmetic products. Clinical symptoms of epiphora settled with topical steroid drops, but the clinical signs of chronic tarsal inflammation persisted until withdrawal of the facial wipes thought to contain the inciting agent, though the exact nature of this remains unclear. CONCLUSION: The presentation, appearances, histological features are consistent with a contact allergen-driven chronic conjunctivitis. Steroid treatment provided good relief of symptoms and patients were advised to avoid potential contact allergens. Management remains difficult. Further research into contact allergies of mucous membranes and identification of its allergens is required.

A difficult diagnosis: severe Graves' ophthalmolopathy.

An 81-year-old woman with atrial fibrillation, on warfarin, with known hyperthyroidism, was admitted to hospital following a fall with proptosis and severely restricted movements in her left eye. Medics initially thought the presentation was related to an intracranial pathology but through subsequent tests and examination, ophthalmologists diagnosed a severe case of thyroid eye disease with intense inflammation. The patient responded well to systemic steroid treatment. This case report highlights a severe rapidly progressing case of thyroid eye disease with diagnostic difficulties arising from multiple comorbidities in an elderly patient.

Diagnosis and Monitoring of Choroidal Osteoma through Multimodal Imaging.

A 16-year-old Caucasian female with a 6-month history of decreased visual acuity and metamorphopsia in the left eye is reported. The fundus of the left eye revealed a well defined lesion in the macula region. Diagnosis of choroidal osteoma was established using spectral domain optical coherence tomography (OCT), fundus fluorescein angiography (FFA), indocyanine green angiography (ICG), and B-scan ultrasonography. Subretinal fluid (SRF) and retinal pigment epithelium (RPE) detachment were noted in the absence of obvious classic choroidal neovascularisation (CNV). The patient was followed up for over 13 months without any treatment in the interim and the lesion was noted to have enlarged but visual acuity and SRF had remained stable. We report an interesting case where subretinal fluid was noted in the absence of evident choroidal neovascularisation and provide an example of the imaging modalities application in the era of "optical biopsy."

Defecation pain and coccydynia due to an anteverted coccyx: a case report.

INTRODUCTION: Defecation pain is a common problem with many etiologies implicated. Elucidating a cause requires a thorough medical history, examination and appropriate investigations, which may include endoscopy, barium enema, examination under anesthesia and magnetic resonance imaging or computed tomography. Coccydynia is a term used to describe pain in the region of the coccyx, often due to abnormal mobility of the coccyx. Non-surgical management options remain the gold-standard for coccydynia with surgery being reserved for complicated cases. CASE PRESENTATION: This is a case of a 67-year-old Caucasian man who presented with a two-and-a-half-year history of worsening rectal pain. CONCLUSION: To the best of our knowledge, we describe the first case in the literature of an abnormally mobile anteverted coccyx causing predominantly defecation pain and coccydynia, successfully treated by coccygectomy. When first-line investigations fail to elucidate a cause of defecation pain one must, in the presence of unusual symptoms, consider musculoskeletal pathologies emanating from the coccyx and an orthopedic consultation must then be sought for diagnostic purposes.

Calcium pyrophosphate dihydrate deposition in the trochanteric hip bursa presenting as acute hip pain.

Acute hip pain is a common reason for attendance to hospital. Immediate diagnoses include occult fractures, infectious and non-infectious inflammatory processes such as gout and pseudogout. Calcium pyrophosphate deposition disease (CPDD) is a rheumatological syndrome affecting articular cartilage and/or synovial fluid. It can occur as a clinical presentation (pseudogout) where calcium pyrophosphate dihydrate (CPPD) crystals are deposited within the joint space or radiographically, as chondrocalcinosis (CC), where CPPD crystals are deposited onto articular cartilages. Extraarticular manifestations of CPDD are rare. The authors report a case of CPPD deposition in the trochanteric bursa of a 35-year-old woman presenting as acute hip pain. The patient was treated successfully during arthroscopy with removal of the deposits and excision of the bursa. The patient remains well at 6 month follow-up.

Angiomatous meningioma of orbit mimicking as malignant neoplasm: a case report and literature review.

Angiomatous meningioma is a rare and distinct meningioma variant characterised with predominance of microvascularcomponent.There are few reported cases in literature with limited information on ophthalmic manifestations and radiological findings. There is no consistent feature reported so far of this neoplasm to aid in its diagnosis. Authors report an interesting case of Angiomatous Meningioma presenting as an aggressively expanding orbital mass lesion with adjacent bony destruction mimicking a malignant neoplasm.