Skin microbiota dynamics following B. subtilis formulation challenge: an in vivo study in mice.

BACKGROUND: Modulating the microbiota is a leading-edge strategy for the restoration and maintenance of a healthy, balanced environment. The use of health-promoting bacteria has demonstrated some potential benefits as an alternative for skin microbiota intervention. Here, we investigate the manipulation of mice skin microbiota using B. subtilis incorporated into a supportive Pluronic F-127 hydrogel formulation. The formula plays an important role in delivering the bacteria to the desired action site. RESULTS: The B. subtilis challenge induced a shift in the composition and abundance of the skin microbiota. Containment of B. subtilis in the Pluronic F-127 hydrogel accelerated bacterial modulation compared with free B. subtilis. The abundance of both Staphylococcus and Corynebacterium spp. was altered as a result of the live bacterial intervention: the abundance of Corynebacterium increased while that of Staphylococcus decreased. Four days after last application of the B. subtilis formulation, B. subtilis counts returned to its initial level. CONCLUSIONS: B. subtilis intervention can induce a shift in the skin microbiota, influencing the abundance of commensal, beneficial, and pathogenic bacteria. Containment of B. subtilis in Pluronic hydrogel accelerates the microbial alteration, probably by facilitating bacterial attachment and supporting continuous growth. Our results reveal the ability of B. subtilis in Pluronic to modulate the skin microbiota composition, suggesting that the formulation holds therapeutic potential for skin disease treatment.

Glutathione-Conjugated Hydrogels: Flexible Vehicles for Personalized Treatment of Bacterial Infections.

PURPOSE: Skin and soft tissue infections are increasingly prevalent and often complicated by potentially fatal therapeutic hurdles, such as poor drug perfusion and antibiotic resistance. Delivery vehicles capable of versatile loading may improve local bioavailability and minimize systemic toxicities yet such vehicles are not clinically available. Therefore, we aimed to expand upon the use of glutathione-conjugated poly(ethylene glycol) GSH-PEG hydrogels beyond protein delivery and evaluate the ability to deliver traditional therapeutic molecules. METHODS: PEG and GSH-PEG hydrogels were prepared using ultraviolet light (UV)-polymerization. Hydrogel loading and release of selected drug candidates was examined using UV-visible spectrometry. Therapeutic molecules and GST-fusion protein loading was examined using UV-visible and fluorescent spectrometry. Efficacy of released meropenem was assessed against meropenem-sensitive and -resistant P. aeruginosa in an agar diffusion bioassay. RESULTS: For all tested agents, GSH-PEG hydrogels demonstrated time-dependent loading whereas PEG hydrogels did not. GSH-PEG hydrogels released meropenem over 24 h. Co-loading of biologic and traditional therapeutics into a single vehicle was successfully demonstrated. Meropenem-loaded GSH-PEG hydrogels inhibited the growth of meropenem-sensitive and resistant P. aeruginosa isolates. CONCLUSION: GSH ligands within GSH-PEG hydrogels allow loading and effective delivery of charged therapeutic agents, in addition to biologic therapeutics.

Radiolabeled Tedizolid Phosphate Liposomes for Topical Application: Design, Characterization, and Evaluation of Cellular Binding Capacity.

Nowadays, the incidence of acute bacterial skin and skin structure infection (ABSSSI) is increasing. The increased bioavailability and reduced drug resistance of antibiotics are crucial to obtain a more effective treatment response in these infections. These favorable properties could be achieved by different drug delivery systems such as liposomes. In this study, nanosized, radiolabeled tedizolid phosphate liposomal formulations were prepared and evaluated with their in vitro cellular binding capacity and biocompatible profile for topical treatment of ABSSSI. Liposomes were characterized by evaluation of their visual inspection, particle size (about 190-270 nm), zeta potential value (around 0), and encapsulation efficiency (nearly 10%). The release rate of tedizolid phosphate from liposomes was also studied using dialysis membranes and evaluated kinetically. The stability of formulations was observed at three different temperatures and humidity conditions for 28 days. Afterward, liposomes were labeled with 99mTc, and the optimal amount of reducing agent (stannous chloride) was determined as 500 µg in this direct labeling procedure. All liposome formulations were successfully radiolabeled with high efficiency and exhibited high radiochemical purity (> 80%) during 6 h in different media. Furthermore, the cellular bindings of liposomal formulations were evaluated in human skin fibroblast cells by measuring the radioactivity. Higher radioactivity values were obtained in CCD-1070Sk cells incubated by liposome formulations compared to sodium pertechnetate. This finding suggested that liposomal formulation increased the cellular binding of radioactivity. By the result of our study, nanosized, tedizolid phosphate encapsulated liposome formulation was found to be a favorable carrier system in the treatment of ABSSSI.

Linezolid as a treatment option for cutaneous non-tuberculous mycobacterial infections.

Cutaneous non-tuberculous mycobacterial (NTM) infections have rapidly increased in incidence in recent years. Currently there is no standard treatment and the variable and nonspecific ways in which cutaneous NTM infection presents makes it a therapeutic and diagnostic challenge. We describe a 67-year-old immunocompetent woman with cutaneous NTM infection after she recently underwent a root canal procedure. Although the species was not identified and she was unable to tolerate multiple antibiotics, she ultimately responded well to three months of treatment with linezolid. Given that cutaneous NTM infection can present in immunocompetent patients and that the incidence is rising, it is important for clinicians to maintain a high index of clinical suspicion, especially in patients with a recent history of surgery, trauma, or cosmetic procedures. Linezolid has coverage against non-tuberculous mycobacteria and is an effective therapeutic option for cutaneous NTM cases in which identification to the species level is not possible or when adverse effects limit therapeutic options.

An Integrated Safety Summary of Omadacycline, a Novel Aminomethylcycline Antibiotic.

Omadacycline is a semisynthetic tetracycline antibiotic. Phase III clinical trial results have shown that omadacycline has an acceptable safety profile in the treatment of acute bacterial skin and skin structure infections and community-acquired bacterial pneumonia. Similar to most tetracyclines, transient nausea and vomiting and low-magnitude increases in liver aminotransferases were the most frequent treatment-emergent adverse events in phase III studies but were not treatment limiting. Package insert warnings and precautions for omadacycline include tooth discoloration; enamel hypoplasia; inhibition of bone growth following use in late pregnancy, infancy, or childhood up to 8 years of age; an imbalance in mortality (2%, compared with 1% in moxifloxacin-treated patients) was observed in the phase III study in patients with community-acquired bacterial pneumonia. Omadacycline has no effect on the QT interval, and its affinity for muscarinic M2 receptors resulted in transient heart rate increases following dosing.

Primary cutaneous actinomycosis: a diagnosis consideration in people living with HIV/AIDS.

BACKGROUND: Owing to similar clinical presentations, as of cutaneous disease of different etiologies, and extreme rarity in the global incidence; primary cutaneous actinomycosis often remains as diagnostic challenges. CASE PRESENTATION: Herein, we describe a case of primary cutaneous actinomycosis, erroneously treated as cutaneous tuberculosis, in a patient living with AIDS. On clinical examination, the characteristic lesion, resembling cutaneous tuberculosis, observed on the dorsum of a left leg. No other lesion elsewhere on the body was observed, however. Cytological examinations of the stabbed biopsy were negative for malignant cells; although hyper-keratosis and mild-acanthosis of epidermis, acute inflammatory infiltrates comprising plasma cell, macrophages and neutrophils were observed in the upper and mid dermis. The pus aspirated from lesion grew a molar tooth, adherent colonies in microaerophilic condition. Further, identifications and susceptibility pattern against recommended antibiotics were assessed as per the CLSI (Clinical and Laboratory Standard Institute) guidelines. Subsequently, the case was then, diagnosed as primary cutaneous actinomycosis. Radiographic imaging of abdomen and lungs were normal; no feature of disseminated actinomycosis seen. Penicillin G followed by Penicillin V, was prescribed for 12 months. The patient underwent progressive changes and no relapse noted on periodic follow-up. CONCLUSION: The case underscores cutaneous actinomycosis requires a diagnosis consideration, especially in People Living with HIV/AIDS (PLHA), where myriad of opportunistic cutaneous infections are common.

Anti-biofilm properties of a mupirocin spray formulation against Escherichia coli wound infections.

Mupirocin ointment is a widely used topical drug for the treatment of bacterial skin infections. However, ointments have some limitations which motivated the development of a film forming spray of mupirocin. Mupirocin spray (2%) was formulated with Eudragit E100 as a film forming agent and tested for its antibacterial and anti-biofilm activities against Escherichia coli, a skin pathogen causing wound and surgical site infections. Treatment with mupirocin spray resulted in significant antibacterial and anti-biofilm activities (inhibition and disruption) with single spray and sub-actual dose concentrations at par with the commercial ointment concentration. The spray formulation was found to be non-toxic to fibroblast cells and greatly resisted removal from the site of application upon washing, in contrast to the ointment which was significantly removed after a single wash. This is the first study to develop and evaluate a spray formulation for mupirocin that forms a stable thin film for sustained release of the drug.

Preoperative skin antiseptics for prevention of cardiac implantable electronic device infections: a historical-controlled interventional trial comparing aqueous against alcoholic povidone-iodine solutions.

AIMS: Local skin antiseptic prevention against cardiac implantable electronic device (CIED) infections is not yet fully understood. This monocentre historical-controlled study sought to (i) conduct a prospective observational analysis comparing two antiseptic skin preparations over two similar consecutive periods of time, one conducted over a 1-year period using an aqueous povidone-iodine solution (Group I) and the other over the following with an alcoholic povidone-iodine solution (Group II); (ii) determine the predictive factors of CIED infection. METHODS AND RESULTS: Cardiac implantable electronic device implantation was performed in 1326 patients (pts). A total of 32 pts (2.4%) developed a CIED infection. Long-term follow-up (26 ± 3 months) revealed no significant difference between the groups: infections were observed in 14 of the 648 pts (2.2%) in Group I vs. 18 of the 678 pts (2.7%) in Group II (P = 0.9). Single- and multiple-variable logistic regression analyses were performed to identify risk factors; adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated. The occurrence of infection was positively correlated with re-intervention (aOR, 7.16; 95% CI, 2.56-19.99; P < 0.0001), number of generator replacements, mean (aOR, 3.47; 95% CI, 2.22-5.44; P < 0.001), and haematoma (aOR, 48.4; 95% CI, 13.45-174.25; P < 0.0001). CONCLUSION: This study found that aqueous and alcoholic povidone-iodine solutions displayed similar antiseptic effects regarding CIED infection prevention. Independent predictive factors of CIED infection were re-intervention, haematoma, and number of generator replacements.

Toxic epidermal necrolysis complicating antibiotic treatment of puerperal endometritis: a case report.

The aim of the study is to describe a case report of Lyell syndrome (toxic epidermal necrolysis) involving 63% of body surface which has been associated with antibiotic therapy of mild peurperal endometritis in woman 3 weeks postpartum. Lyell syndrome is a severe life-threatening condition developing due to idiosyncrazy (alergic reaction type IV), most commonly after administration of drugs. Incidence quoted in literature is around 1:1-2000000. Illness severity can be assessed using a SCORTEN scoring system, which predicts patient mortality based on seven independent factors. Lyell syndrome is a very rare but potentially lethal complication of antibiotic treatment.

Mycobacterium chelonae associated with tumor-like skin and oral masses in farmed Russian sturgeons (Acipenser gueldenstaedtii).

BACKGROUND: Non-tuberculous mycobacteria responsible for piscine mycobacteriosis usually produce visceral granulomas in both freshwater and marine species. In this study, the first occurrence of Mycobacterium chelonae associated with tumor-like lesions in the Russian sturgeon (Acipenser gueldenstaedtii) is reported. Fifteen sturgeons from an Italian fish farm showing skin and oral cauliflower-like masses were investigated by histopathology, bacterial culture and molecular analyses. RESULTS: A total of 20 masses different in size located in the mouth and in pectoral and caudal fins (characterized by abundant calcium deposits and by mild to moderate granulomatous inflammation) were observed with a significant different degree of histological severity. All internal organs of the fish were negative for mycobacteria, Ziehl-Neelsen was positive in only one of the oral masses, whereas bacterial and PCR analyses detected the presence of M. chelonae for almost all the skin and oral masses. Based on these results, a calcinosis of dystrophic origin associated with a chronic granulomatous inflammation was considered as a primary diagnosis consequent to tissue injury in areas susceptible to trauma. CONCLUSIONS: We hypothesized that the occurrence of M. chelonae in farmed sturgeons was only a secondary event related to its presence in a stressful rearing environment and subsequent to a dystrophic calcinosis occurred in previously damaged tissues.

Ultrasound-guided diagnosis of occult mandibular osteomyelitis.

BACKGROUND: Skin and soft-tissue infections (SSTIs) are common disease presentations to the emergency department (ED), with the majority of the infections attributed to community-acquired methicillin-resistant Staphylococcus aureus. Rapid and accurate identification of potentially serious SSTIs is critical. Clinician-performed ultrasonography (CPUS) is increasingly common in the ED, and assists in rapid and accurate identification of a variety of disease processes. CASE REPORT: A 21-year-old female presented to the ED with chin swelling and "boils." Although her visual examination was benign, CPUS of her facial swelling quickly established a more concerning disease process, which was eventually confirmed by aspiration and bone biopsy to be mandibular osteomyelitis. The causative organism, Serratia odorifera, is rarely associated with infections, and we are aware of no previously reported cases of osteomyelitis due to this species. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: In this case of mandibular osteomyelitis, CPUS rapidly and accurately identified abnormal bony cortex of the mandible and an associated fluid collection. CPUS of an otherwise benign presentation of a facial infection led to a maxillofacial computed tomography scan, aspiration and biopsy, and then elective debridement of the bone infection. Emergency physicians should be aware of the utility of CPUS and the need to carefully investigate SSTIs presenting to the ED.

Management of complications of injectable silicone.

Soft tissue augmentation is a common procedure, and a wide variety of injectable fillers are used. Liquid injectable silicone (LIS) was the first highly popularized injectable filler. LIS is a permanent filler and can be used in the correction of facial furrows and wrinkles. Some complications are inherent to the procedure and can resolve spontaneously, such as redness, swelling, and immediate hypersensitivity reactions. Unintended reactions, such as granulomas, infections, vascular occlusion, can also follow the treatment with LIS and may appear several years after the injections. These can be difficult to manage, show little or no tendency to spontaneous resolutions, and rarely resolve completely. Injecting physicians must be aware of these potential complications caused by LIS because early medical care and treatment, including psychological support for these patients, can minimize the consequences for patients and physicians, and may also help obtaining better outcomes when treating complications.

Complications of collagen fillers.

As the skin ages, a deficiency in collagen occurs, thus injectable collagen products have become a sensible and popular option for dermal filling and volume enhancement. Several types of collagen have been developed over the years, including animal sources such as bovine and porcine collagen, as well as human-based sources derived from pieces of the patient's own skin, cadaver skin, and later cultured from human dermal fibroblasts. While collagen overall has a relatively safe, side effect profile, there are several complications, both early and late onset, that practitioners and patients should be aware of. Early complications, occurring within days of the procedure, can be divided into non-hypersensitivity and hypersensitivity reactions. The non-hypersensitive reactions include injection site reactions, discoloration, maldistribution, infection, skin necrosis, and the very rare but dreaded risk of vision loss, whereas the hypersensitivity reactions present usually as delayed type IV reactions, but can also rarely present as an immediate type I reaction. Late complications, occurring within weeks to even years after injection, include granuloma formation, foreign body reactions, and infection secondary to atypical mycobacteria or biofilms. This review will give a detailed overview of the complications secondary to cutaneous collagen injections.

Inactivation of cyclic Di-GMP binding protein TDE0214 affects the motility, biofilm formation, and virulence of Treponema denticola.

As a ubiquitous second messenger, cyclic dimeric GMP (c-di-GMP) has been studied in numerous bacteria. The oral spirochete Treponema denticola, a periodontal pathogen associated with human periodontitis, has a complex c-di-GMP signaling network. However, its function remains unexplored. In this report, a PilZ-like c-di-GMP binding protein (TDE0214) was studied to investigate the role of c-di-GMP in the spirochete. TDE0214 harbors a PilZ domain with two signature motifs: RXXXR and DXSXXG. Biochemical studies showed that TDE0214 binds c-di-GMP in a specific manner, with a dissociation constant (Kd) value of 1.73 µM, which is in the low range compared to those of other reported c-di-GMP binding proteins. To reveal the role of c-di-GMP in T. denticola, a TDE0214 deletion mutant (TdΔ214) was constructed and analyzed in detail. First, swim plate and single-cell tracking analyses showed that TdΔ214 had abnormal swimming behaviors: the mutant was less motile and reversed more frequently than the wild type. Second, we found that biofilm formation of TdΔ214 was substantially repressed (∼6.0-fold reduction). Finally, in vivo studies using a mouse skin abscess model revealed that the invasiveness and ability to induce skin abscesses and host humoral immune responses were significantly attenuated in TdΔ214, indicative of the impact that TDE0214 has on the virulence of T. denticola. Collectively, the results reported here indicate that TDE0214 plays important roles in motility, biofilm formation, and virulence of the spirochete. This report also paves a way to further unveil the roles of the c-di-GMP signaling network in the biology and pathogenicity of T. denticola.

Full-genome dissection of an epidemic of severe invasive disease caused by a hypervirulent, recently emerged clone of group A Streptococcus.

Group A Streptococcus (GAS) causes an exceptionally broad range of infections in humans, from relatively mild pharyngitis and skin infections to life-threatening necrotizing fasciitis and toxic shock syndrome. An epidemic of severe invasive human infections caused by type emm59 GAS, heretofore an exceedingly rare cause of disease, spread west to east across Canada over a 3-year period (2006 to 2008). By sequencing the genomes of 601 epidemic, historic, and other emm59 organisms, we discovered that a recently emerged, genetically distinct emm59 clone is responsible for the Canadian epidemic. Using near-real-time genome sequencing, we were able to show spread of the Canadian epidemic clone into the United States. The extensive genome data permitted us to identify patterns of geographic dissemination as well as links between emm59 subclonal lineages that cause infections. Mouse and nonhuman primate models of infection demonstrated that the emerged clone is unusually virulent. Transmission of epidemic emm59 strains may have occurred primarily by skin contact, as suggested by an experimental model of skin transmission. In addition, the emm59 strains had a significantly impaired ability to persist in human saliva and to colonize the oropharynx of mice, and seldom caused human pharyngitis. Our study contributes new information to the rapidly emerging field of molecular pathogenomics of bacterial epidemics and illustrates how full-genome data can be used to precisely illuminate the landscape of strain dissemination during a bacterial epidemic.

Complications of injectable fillers, part I.

Dermal filling has rapidly become one of the most common procedures performed by clinicians worldwide. The vast majority of treatments are successful and patient satisfaction is high. However, complications, both mild and severe, have been reported and result from injection of many different types of dermal fillers. In this Continuing Medical Education review article, the author describes common technical errors, the signs and symptoms of both common and rare complications, and management of sequelae in clear, easily adaptable treatment algorithms.

Transdermal Delivery of Photosensitizer-Catalase Conjugate by Fluorinated Polyethylenimine for Enhanced Topical Photodynamic Therapy of Bacterial Infections.

Pathogenic bacteria induce subcutaneous infections pose serious threats to global public health. Recently, photodynamic therapy (PDT) has been proposed as a non-invasive approach for anti-microbial treatment without the risk to induce drug resistance. However, due to the hypoxic environment of most anaerobiont-infected sites, the therapeutic efficacy of oxygen consuming PDT has been limited. Herein, a transdermal delivery system is reported to allow effective delivery of photosensitizers into infected skin for PDT treatment of skin infections by bacteria. Considering the overproduction of hydrogen peroxide (H2 O2 ) in the abscess area, catalase (CAT), an enzyme that triggers H2 O2 decomposition to generate O2 , is conjugated with chlorine e6 (Ce6) to form a photosensitizer conjugate (Ce6-CAT) as an enhanced PDT agent against Staphylococcus Aureus. After screening a series of fluorinated low molecular weight polyethylenimine (F-PEI) with different fluorination degrees, the optimized F-PEI formulation is identified with the best transdermal delivery ability system. Upon mixing, the formed Ce6-CAT@F-PEI nanocomplex shows effective transdermal penetration after being applied to the skin surface. With light exposure of the infected skin, highly effective in vivo anti-bacterial PDT therapeutic effect with Ce6-CAT@F-PEI is observed. This work proposes a transdermal PDT therapeutic nanomedicine particularly promising for the anti-bacterial treatment of skin infections.

Rare human skin infection with Corynebacterium ulcerans: transmission by a domestic cat.

Corynebacterium ulcerans is mainly known for its ability to cause animal infections. Some strains of C. ulcerans produce diphtheria toxin, which can cause life-threatening cardiopathies and neuropathies in humans. Human cutaneous C. ulcerans infection is a very rare disease that mimics classical cutaneous diphtheria. We present a very rare case of a C. ulcerans skin infection caused by a non-diphtheria toxin-producing strain of C. ulcerans that resolved after 3 weeks of therapy with amoxicillin-clavulanate. A pet cat was the probable source of infection. The presence of C. ulcerans in the mouth of the cat was confirmed by 16S rRNA gene analysis and the API Coryne system. In cases of human infection with potentially toxigenic corynebacteria, it is important to determine the species and examine the isolate for diphtheria toxin production. If toxigenicity is present, diphtheria antitoxin should be administered immediately. Carriers and potential infectious sources of C. ulcerans include not only domestic livestock but also pet animals. For the primary prevention of disease caused by diphtheria toxin-producing corynebacteria, vaccination with diphtheria toxoid is recommended.

Potential of ceragenin CSA-13 and its mixture with pluronic F-127 as treatment of topical bacterial infections.

AIMS: Ceragenin CSA-13 is a synthetic mimic of cationic antibacterial peptides, with facial amphiphilic morphology reproduced using a cholic acid scaffold. Previous data have shown that this molecule displays broad-spectrum antibacterial activity, which decreases in the presence of blood plasma. However, at higher concentrations, CSA-13 can cause lysis of erythrocytes. This study was designed to assess in vitro antibacterial and haemolytic activity of CSA-13 in the presence of pluronic F-127. METHODS AND RESULTS: CSA-13 bactericidal activity against clinical strains of bacteria associated with topical infections and in an experimental setting relevant to their pathophysiological environment, such as various epithelial tissue fluids and the airway sputum of patients suffering from cystic fibrosis (CF), was evaluated using minimum inhibitory and minimum bactericidal concentration (MIC/MBC) measurements and bacterial killing assays. We found that in the presence of pluronic F-127, CSA-13 antibacterial activity was only slightly decreased, but CSA-13 haemolytic activity was significantly inhibited. CSA-13 exhibits bacterial killing activity against clinical isolates of Staphylococcus aureus, including methicillin-resistant strains, Pseudomonas aeruginosa present in CF sputa, and biofilms formed by different Gram (+) and Gram (-) bacteria. CSA-13 bactericidal action is partially compromised in the presence of plasma, but is maintained in ascites, cerebrospinal fluid, saliva, and bronchoalveolar lavage fluid. The synergistic action of CSA-13, determined by the use of a standard checkerboard assay, reveals an increase in CSA-13 antibacterial activity in the presence of host defence molecules such as the cathelicidin LL-37 peptide, lysozyme, lactoferrin and secretory phospholipase A (sPLA). CONCLUSION: These results suggest that CSA-13 may be useful to prevent and treat topical infection. SIGNIFICANCE AND IMPACT OF THE STUDY: Combined application of CSA-13 with pluronic F-127 may be beneficial by reducing CSA-13 toxicity.

Photodynamic therapy for infections: clinical applications.

BACKGROUND AND OBJECTIVE: Photodynamic therapy (PDT) was discovered over 100 years ago by its ability to kill various microorganisms when the appropriate dye and light were combined in the presence of oxygen. However it is only in relatively recent times that PDT has been studied as a treatment for various types of localized infections. This resurgence of interest has been partly motivated by the alarming increase in drug resistance amongst bacteria and other pathogens. This review will focus on the clinical applications of antimicrobial PDT. STUDY DESIGN/MATERIALS AND METHODS: The published peer-reviewed literature was reviewed between 1960 and 2011. RESULTS: The basics of antimicrobial PDT are discussed. Clinical applications of antimicrobial PDT to localized viral infections caused by herpes and papilloma viruses, and nonviral dermatological infections such as acne and other yeast, fungal and bacterial skin infections are covered. PDT has been used to treat bacterial infections in brain abscesses and non-healing ulcers. PDT for dental infections including periodontitis and endodontics has been well studied. PDT has also been used for cutaneous Leishmaniasis. Clinical trials of PDT and blue light alone therapy for gastric Helicobacter pylori infection are also covered. CONCLUSION: As yet clinical PDT for infections has been mainly in the field of dermatology using 5-aminolevulanic acid and in dentistry using phenothiazinium dyes. We expect more to see applications of PDT to more challenging infections using advanced antimicrobial photosensitizers targeted to microbial cells in the years to come.