Hot tub folliculitis or hot hand–foot syndrome caused by Pseudomonas aeruginosa

Genomic and metabolic versatility of Pseudomonas aeruginosa contributes to its inter-kingdom transmission and survival

Pseudomonas aeruginosa is one of the most versatile bacteria with renowned pathogenicity and extensive drug resistance. The diverse habitats of this bacterium include fresh, saline and drainage waters, soil, moist surfaces, taps, showerheads, pipelines, medical implants, nematodes, insects, plants, animals, birds and humans. The arsenal of virulence factors produced by P. aeruginosa includes pyocyanin, rhamnolipids, siderophores, lytic enzymes, toxins and polysaccharides. All these virulent elements coupled with intrinsic, adaptive and acquired antibiotic resistance facilitate persistent colonization and lethal infections in different hosts. To date, treating pulmonary diseases remains complicated due to the chronic secondary infections triggered by hospital-acquired P. aeruginosa. On the contrary, this bacterium can improve plant growth by suppressing phytopathogens and insects. Notably, P. aeruginosa is one of the very few bacteria capable of trans-kingdom transmission and infection. Transfer of P. aeruginosa strains from plant materials to hospital wards, animals to humans, and humans to their pets occurs relatively often. Recently, we have identified that plant-associated P. aeruginosa strains could be pathologically similar to clinical isolates. In this review, we have highlighted the genomic and metabolic factors that facilitate the dominance of P. aeruginosa across different biological kingdoms and the varying roles of this bacterium in plant and human health.

Pseudomonas Infection Outbreak Associated with a Hotel Swimming Pool - Maine, March 2023

Treated recreational water venues (e.g., pools and hot tubs) located at hotels represent one third of sources of reported treated recreational water-associated outbreaks; when these outbreaks are caused by Pseudomonas aeruginosa, they predominantly occur during January-April. On March 8, 2023, the Maine Center for Disease Control and Prevention (Maine CDC) initiated an investigation in response to reports of illness among persons who had used a swimming pool at hotel A during March 4-5. A questionnaire was distributed to guests who were at hotel A during March 1-7. Among 35 guests who responded, 23 (66%) developed ear pain, rash, or pain or swelling in feet or hands within days of using the pool during March 4-5. P. aeruginosa, a chlorine-susceptible bacterium, was identified in cultures obtained from skin lesions of three patients; a difference of two single nucleotide polymorphisms was found between isolates from two patients' specimens, suggesting a common exposure. Hotel A management voluntarily closed the pool, and Maine CDC's Health Inspection Program identified multiple violations, including having no disinfectant feeder system, all of which had been identified during a previous inspection. Because chlorine had been added to the pool water after the pool was voluntary closed, environmental samples were not collected. The pool remained closed until violations were addressed. Health departments can play an important role in reducing the risk for outbreaks associated with hotel pools and hot tubs. This reduction in risk can be achieved by collaborating with operators to ensure compliance with public health codes, including maintaining chlorine concentration and otherwise vigilantly managing the pool, and by disseminating prevention messages to pool and hot tub users.

Environmental surveillance of Pseudomonas aeruginosa in recreational waters in tourist facilities of the Balearic Islands, Spain (2016-2019)

BACKGROUND

Pseudomonas aeruginosa is a major opportunistic human pathogen commonly connected with recreational water activities. Spain is a tourist destination where most of the establishments have swimming pool. Nevertheless, the prevalence of P. aeruginosa in public swimming pools in our country is unknown. This works aimed to survey the P. aeruginosa presence in tourist Spanish recreational waters.

METHOD

Tourist recreational water in hotels in the Balearic Islands were visited for four years (2016-2019). The levels of selected parameters were determined, and their correlation with P. aeruginosa contamination investigated.

RESULTS

We evaluated 11,014 samples from 254 facilities. Unacceptable levels of at least one legislated parameter were detected in 30.7% of cases, implicating closure in 15.9%, being P. aeruginosa the leading cause of closure. The prevalence of the pathogen was 14.2%, with lower presence in outer swimming pools. Disinfectant levels influence P. aeruginosa contamination, and bromine-maintained pools were more often contaminated than those treated with chlorine. Prevalence remained constant over the years, although it increased in 2019.

CONCLUSIONS

P. aeruginosa prevalence in our recreational waters is similar to other countries, and the contamination rates depend on the installations and type and disinfectant levels. Corrective measures are still needed to improve pathogen control.

The Yin and Yang of Skin Microbiota in "Swimmer Acne"

Cutibacterium acnes (C. acnes) is an organism implicated in the pathogenesis of acne. Despite regular immersion in antimicrobial chlorine, adolescent swimmers suffer from acne and tend to be resistant to standard therapies. Given the presence of Pseudomonas within swimming facilities, we hypothesized that "swimmer acne" is potentially driven by a different microbial mechanism. In this study, we aimed to examine the microbial dynamics of C. acnes and Pseudomonadaceae, a family of Gram-negative bacteria (includes Pseudomonas aeruginosa), in swimmers and its potential contribution to pathogenesis of acne in this population. Using fluorescence photography that measures the Coproporphyrin III (CPIII), we quantitated an absolute abundance of C. acnes present on the face of each participant pre- and post-swimming. In addition, 16S rRNA gene sequencing was utilized to assess relative abundance of the skin microbiota on each participant pre- and post-swimming. 16 swimmers (8 girls and 8 boys) completed the study. Seven had acne on the face. The CPIII fluorescence levels decreased for all swimmers after 1 hour of swimming (p-value <0.001). In contrast, relative abundance of C. acnes remained unchanged, while that of Pseudomonadaceae increased after swimming (p-value = 0.027). Comparing the relative abundances of Pseudomonadaceae before swimming, there was a significant increase in variance from the mean in acne group as compared to no acne group (p-value <0.001). Taken together, we conclude that the skin dysbiosis resulting from repeated decolonization and colonization of C. acnes and Pseudomonadaceae, respectively, can potentially be associated with the pathogenesis of acne in swimmers.

Enhancement of photodynamic bactericidal activity of curcumin against Pseudomonas Aeruginosa using polymyxin B

BACKGROUND

Pseudomonas aeruginosa (P. aeruginosa) is an emerging opportunistic pathogen, which can cause bacterial skin diseases such as green nail syndrome, interdigital infections and folliculitis. Curcumin-mediated antimicrobial photodynamic therapy (aPDT) has been demonstrated as a promising therapeutic option for the treatment of skin infection though its inactivation of gram-negative bacteria such as P. aeruginosa.

MATERIALS AND METHODS

In the present study, we examined the adjuvant effect of polymyxin B on the antibacterial activity of curcumin-mediated aPDT against P. aeruginosa. P. aeruginosa was treated with curcumin in the presence of 0.1-0.5 mg/L polymyxin B and irradiated by blue LED light (10 J/cm²). Bacterial cultures treated with curcumin alone served as controls. Colony forming units (CFU) were counted and the viability of P. aeruginosa was calculated after aPDT treatment. The possible underlying mechanisms for the enhanced killing effects were also explored.

RESULTS

The killing effects of curcumin-mediated aPDT against P. aeruginosa was significantly enhanced by polymyxin B (over 2-log reductions). Moreover, it was also observed that addition of polymyxin B in the curcumin-mediated aPDT led to the apparent bacterial membrane damage with increased leakage of cytoplasmic contents and extensive DNA and protein degradation.

DISCUSSION

The photodynamic action of curcumin against P. aeruginosa could be significantly enhanced by the FDA-approved drug polymyxin B. Our results highlight the potential of introducing polymyxin B to enhance the effects of aPDT treatment against gram-negative skin infections, in particular, P. aeruginosa.

Acral manifestations associated with infection

Acral lesions are well-known physical findings in various infectious disorders. Although they are often overlooked, they can be the key to the diagnosis of the underlying disease. Considering this, we present an overview of various infectious causes of acral lesions in childhood. In addition, we discuss their characteristic presentation, evolution, and appropriate treatment. To our knowledge, this is the first review covering viral, bacterial and mycotic causes.

Pseudomonas-Contaminated Pool Triggering an Episode of Idiopathic Palmoplantar Hidradenitis

Idiopathic palmoplantar hidradenitis (IPPH) is a disorder that mainly affects the palms and soles of children. Although many cases have been reported to occur after recreational swimming activities, whether IPPH is caused by intense physical activity or by Pseudomonas infection has yet to be proven. We report a case of a 3-year-old girl who presented with IPPH after swimming in a pool with evidence of P. aeruginosa contamination, further solidifying the association between Pseudomonas and IPPH.

Skin manifestations of Pseudomonas aeruginosa infections

PURPOSE OF REVIEW

Pseudomonas aeruginosa is an opportunistic pathogen with considerable morbidity and mortality, particularly in vulnerable hosts. Skin manifestations are common, either representing local inoculation or secondary skin seeding following bloodstream infections. As patients with various predisposing conditions are expanding, we sought to review the most recent published evidence regarding epidemiology, risk factors and diagnosis of skin manifestations of P. aeruginosa.

RECENT FINDINGS

New data exist on epidemiology and diagnosis of skin infections; systemic infections are impacted by multidrug-resistance issues and host immune status.

SUMMARY

Green nail syndrome, toe web infection, hot tub folliculitis, hot hand-foot infection and external otitis are the most common infections originating from the skin per se. Local treatments are the cornerstone and prognosis is favorable in immunocompetent hosts. Ecthyma gangrenosum and P. aeruginosa subcutaneous nodules are usually associated with bloodstream infections and occur primarily in immunocompromised hosts. Necrotizing skin and soft tissue infections occur in diabetic, alcoholic and immunocompromised patients; management requires a multidisciplinary team with surgical approach. Burn wound infections may also be challenging, requiring a specialized team. In all the four latter types of P. aeruginosa skin infections portending significant morbidity and mortality, systemic antibiotics are an integral part of the treatment.

Anti-quorum sensing and antibiofilm potential of 1,8-cineole derived from Musa paradisiaca against Pseudomonas aeruginosa strain PAO1

Pseudomonas aeruginosa is one of the vulnerable opportunistic pathogens associated with nosocomial infections, cystic fibrosis, burn wounds and surgical site infections. Several studies have reported that quorum sensing (QS) systems are controlled the P. aeruginosa pathogenicity. Hence, the targeting of QS considered as an alternative approach to control P. aeruginosa infections. This study aimed to evaluate the anti-quorum sensing and antibiofilm inhibitory potential of Musa paradisiaca against Chromobacterium violaceum (ATCC 12472) and Pseudomonas aeruginosa. The methanol extract of M. paradisiacsa exhibits that better antibiofilm potential against P. aeruginosa. Then, the crude methanol extract was subjected to purify by column chromatography and collected the fractions. The mass-spectrometric analysis of a methanol extract of M. paradisiaca revealed that 1,8-cineole is the major compounds. 1, 8-cineole significantly inhibited the QS regulated violacein production in C. violaceum. Moreover, 1,8-cineole significantly inhibited the QS mediated virulence production and biofilm formation of P. aeruginosa without affecting their growth. The real-time PCR analysis showed the downregulation of autoinducer synthase and transcriptional regulator genes upon 1,8-cineole treatment. The findings of the present study strongly suggested that metabolite of M. paradisiaca impedes P. aeruginosa QS system and associated virulence productions.

[An Itching Pleasure]

An Itching Pleasure Abstract. A 50-year-old female patient presents in the emergency department with an itchy, acneiform exanthema on the trunk and malaise for two days. Laboratory testing showed no abnormalities. After further questioning, the patient reported frequent use of her new whirlpool. Based on the medical history and the clinic we suspected a pseudomonas folliculitis. A bacterial culture of the pustules showed growth of Pseudomonas aeruginosa, which confirmed the diagnosis. Systemic antibiotics were not necessary in the absence of risk factors for severe progress or immunosuppression. The exanthema healed within a few days without any complications by using external disinfectants.

Musa acuminata and its bioactive metabolite 5-Hydroxymethylfurfural mitigates quorum sensing (las and rhl) mediated biofilm and virulence production of nosocomial pathogen Pseudomonas aeruginosa in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Musa acuminata, a tropical plant belongs to the family Musaceae. The fruit peels of this plant have been well documented for their therapeutic value in Asia and Africa. It has also been previously reported for numerous biological applications such as antimicrobial, antioxidant, itching, psoriasis and anti-diarrheal activities. Moreover, M. acuminata peels have been well known for its anti-healing and antiseptic properties and most commonly used for healing wounds and heat burns in South Asian and African traditional medicines.

AIM OF THE STUDY

To evaluate the QS-mediated antibiofilm and antivirulence potential of M. acuminata, and its bioactive metabolites 5-Hydroxymethylfurfural (5HMF) against Pseudomonas aeruginosa.

MATERIALS AND METHODS

The M. acuminata peel methanol extract (MAM) was evaluated for its antibiofilm potential against P. aeruginosa with increasing concentration. Besides, biofilm related phenomenon's such as total biofilm proteins, microcolony formation exopolysaccharides (EPS) and cell surface hydrophobicity (CSH) productions were also examined to support the antibiofilm potential of MAM. Further, MAM was evaluated for its antivirulence efficacy against P. aeruginosa by assessing the protease, LasA protease, LasB elastase, pyocyanin, alginate and rhamnolipid productions at 400 μg ml^-1 concentration. Transcriptional analysis of QS regulated virulence genes expression level was also done by real-time PCR analysis. Then, the MAM was subjected to column chromatography for further fractions and the bioactive compounds present in MAM were identified by gas chromatograph-mass spectrometry analysis. Further, the major compounds such as 5-hydroxymethylfurfural, vaccenic acid and pentanoic acid identified from active fraction of MAM were evaluated for their antibiofilm and antivirulence potential against P. aeruginosa.

RESULTS

MAM significantly inhibited the biofilm formation in P. aeruginosa at 400 μg ml^-1 concentration which also inhibited the production of biofilm proteins, biofilm adherence, EPS and CSH productions to the level of 79%, 82% and 77% respectively. Further, the antivirulence potential was confirmed through numerous virulence inhibition assays. The MAM at 400 μg ml^-1 concentration inhibited the QS-mediated virulence production such as protease, LasA protease, LasB elastase, pyocyanin, alginate and rhamnolipid productions to the level of 77%, 75%, 68%, 80%, 78% and 69% respectively. Moreover, the results of qPCR analysis confirmed the downregulation of QS regulated virulence genes expression upon treatment with MAM. The chromatographic analysis revealed the presence of 5-Hydroxymethylfurfural (5HMF), vaccenic acid and pentanoic acid in MAM and the potential bioactive compounds with antibiofilm and antivirulence was identified as 5-hydroxymethylfurfural, without exerting any growth inhibition in P. aeruginosa.

CONCLUSION

This study investigated the ideal antibiofilm and antivirulence potential of MAM and its bioactive compound 5HMF, and confirms the ethnopharmacological value of these peels against P. aeruginosa infections.

Cationic Intrinsically Disordered Antimicrobial Peptides (CIDAMPs) Represent a New Paradigm of Innate Defense with a Potential for Novel Anti-Infectives

In the search for potential mechanisms underlying the remarkable resistance of healthy skin against infection by soil bacteria like Pseudomonas (P.) aeruginosa we identified fragments of the intrinsically disordered protein hornerin as potent microbicidal agents in the stratum corneum. We found that, independent of the amino acid (AA)-sequence, any tested linear cationic peptide containing a high percentage of disorder-promoting AA and a low percentage of order-promoting AA is a potent microbicidal antimicrobial. We further show that the antimicrobial activity of these cationic intrinsically disordered antimicrobial peptides (CIDAMPs) depends on the peptide chain length, its net charge, lipidation and environmental conditions. The ubiquitous presence of latent CIDAMP sources in nature suggests a common and yet overlooked adapted innate disinfection system of body surfaces. The simple structure and virtually any imaginable sequence or composition of disorder-promoting AA allow the generation of a plethora of CIDAMPs. These are potential novel microbicidal anti-infectives for various bacterial pathogens, including P. aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA) and fungal pathogens like Candida albicans and Cryptococcus neoformans.

Acral-accentuated exanthem in an infant with parechovirus meningitis

We report a case of an infant who had presented with fever and an acral-accentuated rash, for which his cerebrospinal fluid returned positive for parechovirus. He was treated symptomatically and discharged well, with no long-term complications.

Cutaneous infections in the mature patient

Dermatologists must be familiar with the peculiarities of the micro-organisms that may affect the elderly, in order to optimize the diagnosis and treatment of infections, which may affect their skin, especially because the world population is rapidly aging. It is estimated that there will be 434 million individuals over 80 years of age in 2050. Since the elderly population is rapidly increasing and their infections are usually more severe and different from those observed in younger adults, it leads to a statistical increase of the rates regarding hospitalization and mortality caused by infectious diseases among people over 85 years. Other health issues may be involved in the older population. These include nutritional alterations, as malnutrition or obesity, which can aggravate the infections. Also the usual signs and symptoms of infection are subtle or uncharacteristic in elderly patients, and frequently, they are unable to report their symptoms, which can delay the diagnosis. Among the many infections that may affect the elderly we reviewed the most frequent and those that are different in this age group, as herpes zoster, cytomegalovirus, herpes simplex, bacterial skin infections, erysipelas, celullitis, impetigo, folliculitis, furunculosis and carbunculosis, secondary infections, intertrigo (body folds), fungal infection, and scabies.

A Case of Congenital Folliculitis Caused by Pseudomonas aeruginosa in a Preterm Neonate

Intrauterine infections are associated with life-threatening neonatal conditions such as sepsis, intracranial hemorrhage, and chronic lung disease. Herein we present a case of generalized congenital folliculitis caused by Pseudomonas aeruginosa in a preterm neonate of 27 weeks gestational age successfully treated with antibiotics. Folliculitis is an important manifestation of intrauterine P. aeruginosa infection, and prompt, effective treatment is crucial to ensuring a good prognosis.

Marine and Other Aquatic Dermatoses

Occupational and recreational aquatic activity predisposes our population to a wide variety of dermatoses. Sunburn, urticaria, jellyfish stings, and contact dermatitis to rubber equipment are common allergies that are encountered in the aquatic environment. Among the infections, tinea versicolor, intertrigo, and verruca vulgaris are widespread. Swimmer's itch may occur due to skin penetration by schistosome cercariae, while free-floating nematocysts of marine coelenterates may precipitate seabather's eruption. "Suit squeeze" due to cutaneous barotrauma and lymphoedematous peau d'orange due to decompression are rare, described entities. This review serves as a ready reckoner for Indian dermatologists and medical practitioners to identify and manage these conditions.

[Cutaneous lesions during hot-tub hypersensitivity pneumonitis: Pseudomonas folliculitis ?]

BACKGROUND

Interstitial lung disease, cutaneous rash and elevated serum angiotensin converting enzyme (ACE) may suggest diagnoses other than sarcoidosis.

PATIENTS AND METHODS

A 58-year-old man had presented dyspnoea for 2 years with increased angiotensin-converting enzyme, as well as an interstitial syndrome and micronodules. The possibility of sarcoidosis was raised. Systemic corticosteroids resulted in improvement of the dyspnoea although it recurred on dose reduction. We noted fluctuating eczematous macules of the limbs with a histology of aspecific folliculitis. The identification of Mycobacterium avium complex (MAC) in the bronchoalveolar wash prompted us to initiate antimycobacterial therapy, but this was to no avail. Review of the CT-scan and questioning of the patient (daily use of a Jacuzzi for 7 years) resulted in diagnosis of hypersensitivity pneumonitis due to MAC. The cutaneous lesions were taken to indicate "hot tub folliculitis". Discontinuation of hot-tub use and a short course of oral corticosteroids resulted in healing within 4 months, with no recurrence at 2 years.

DISCUSSION

HTL is a form of hypersensitivity pneumonitis due to the presence of MAC in the water of Jacuzzis. This condition regresses spontaneously without treatment on discontinuation of Jacuzzi use. Hot-tub folliculitis due to Pseudomonas aeruginosa (PA) presents as macules and papules on covered skin areas (swimsuit) within 48hours of bathing and often declines within 2 weeks.

CONCLUSION

Our case is original as regards the concomitant lung and cutaneous involvement associated with Jacuzzi use, with an immunoallergic mechanism for the MAC and probably an infectious mechanism for the PA.

Successful treatment of cutaneous protothecosis with liposomal amphotericin and oral itraconazole

Protothecosis is a rare algal infection, affecting primarily immunocompromised hosts. Optimal management is unclear: in-vitro antimicrobial breakpoints are not established and therapeutic decisions are primarily based on case reports. We present a case of cutaneous Prototheca wickerhamii infection in an immunosuppressed 63 year old male, successfully treated with liposomal amphotericin and prolonged itraconazole. Inoculation may have been through frequent hot-tub use, highlighting hot-tub exposure as an infection risk for the immunocompromised host.

Skin-Derived C-Terminal Filaggrin-2 Fragments Are Pseudomonas aeruginosa-Directed Antimicrobials Targeting Bacterial Replication

Soil- and waterborne bacteria such as Pseudomonas aeruginosa are constantly challenging body surfaces. Since infections of healthy skin are unexpectedly rare, we hypothesized that the outermost epidermis, the stratum corneum, and sweat glands directly control the growth of P. aeruginosa by surface-provided antimicrobials. Due to its high abundance in the upper epidermis and eccrine sweat glands, filaggrin-2 (FLG2), a water-insoluble 248 kDa S100 fused-type protein, might possess these innate effector functions. Indeed, recombinant FLG2 C-terminal protein fragments display potent antimicrobial activity against P. aeruginosa and other Pseudomonads. Moreover, upon cultivation on stratum corneum, P. aeruginosa release FLG2 C-terminus-containing FLG2 fragments from insoluble material, indicating liberation of antimicrobially active FLG2 fragments by the bacteria themselves. Analyses of the underlying antimicrobial mechanism reveal that FLG2 C-terminal fragments do not induce pore formation, as known for many other antimicrobial peptides, but membrane blebbing, suggesting an alternative mode of action. The association of the FLG2 fragment with the inner membrane of treated bacteria and its DNA-binding implicated an interference with the bacterial replication that was confirmed by in vitro and in vivo replication assays. Probably through in situ-activation by soil- and waterborne bacteria such as Pseudomonads, FLG2 interferes with the bacterial replication, terminates their growth on skin surface and thus may contributes to the skin's antimicrobial defense shield. The apparent absence of FLG2 at certain body surfaces, as in the lung or of burned skin, would explain their higher susceptibility towards Pseudomonas infections and make FLG2 C-terminal fragments and their derivatives candidates for new Pseudomonas-targeting antimicrobials.

Mycobacterium abscessus hand-and-foot disease in children: rare or emerging disease?

Mycobacterium abscessus is emerging as an important cause of cutaneous infections in sporadic cases and outbreak settings. Although immunosuppressed or elderly patients are most commonly affected, in 2006 an outbreak of clinically distinct cutaneous lesions on the hands and feet caused by M. abscessus in a population of healthy children using a public swimming pool was reported. This article describes an outbreak of skin infection in a population of healthy Italian children attending the same school and using the same swimming pool. In January 2010 we identified three children with multiple, painful nodules on the palms and soles. M. abscessus was isolated from one child's lesions. A public health investigation was conducted and a team of dermatologists and public health officers visited all of the children; 514 children were screened and 29 cases were identified overall. All of the affected children had used the school's swimming pool. These children were treated with oral clarithromycin for 4 to 8 weeks. Because of the long period of time between the presentation and diagnosis of the first cases, the possibility that the number of cases may have been underestimated cannot be excluded. To our knowledge, this is the second largest reported cluster of M. abscessus skin infection suspected to be related to swimming pool exposure in a population of otherwise healthy children. It is unclear whether this disease is rare or should be considered as an emerging clinical entity.

First report of a Chinese PFOS alternative overlooked for 30 years: its toxicity, persistence, and presence in the environment

This is the first report on the environmental occurrence of a chlorinated polyfluorinated ether sulfonate (locally called F-53B, C8ClF16O4SK). It has been widely applied as a mist suppressant by the chrome plating industry in China for decades but has evaded the attention of environmental research and regulation. In this study, F-53B was found in high concentrations (43-78 and 65-112 μg/L for the effluent and influent, respectively) in wastewater from the chrome plating industry in the city of Wenzhou, China. F-53B was not successfully removed by the wastewater treatments in place. Consequently, it was detected in surface water that receives the treated wastewater at similar levels to PFOS (ca. 10-50 ng/L) and the concentration decreased with the increasing distance from the wastewater discharge point along the river. Initial data presented here suggest that F-53B is moderately toxic (Zebrafish LC50-96 h 15.5 mg/L) and is as resistant to degradation as PFOS. While current usage is limited to the chrome plating industry, the increasing demand for PFOS alternatives in other sectors may result in expanded usage. Collectively, the results of this work call for future assessments on the effects of this overlooked contaminant and its presence and fate in the environment.

Blue light (470 nm) effectively inhibits bacterial and fungal growth

Blue light (470 nm) LED antimicrobial properties were studied alone against bacteria and with or without the food grade photosensitizer, erythrosine (ERY) against filamentous fungi. Leuconostoc mesenteroides (LM), Bacillus atrophaeus (BA) or Pseudomonas aeruginosa (PA) aliquots were exposed on nutrient agar plates to Array 1 (AR1, 0·2 mW cm(-2)) or Array 2 (AR2, 80 mW cm(-2)), which emitted impure or pure blue light (0-300 J cm(-2)), respectively. Inoculated control (room light only) plates were incubated (48 h) and colonies enumerated. The antifungal properties of blue light combined with ERY (11·4 and 22·8 μmol l(-1)) on Penicillium digitatum (PD) and Fusarium graminearum (FG) conidia were determined. Conidial controls consisted of: no light, room light-treated conidia and ERY plus room light. Light-treated (ERY + blue light) conidial samples were exposed only to AR2 (0-100 J cm(-2)), aliquots spread on potato dextrose agar plates, incubated (48 h, 30°C) and colonies counted. Blue light alone significantly reduced bacterial and FG viability. Combined with ERY, it significantly reduced PD viability. Blue light is lethal to bacteria and filamentous fungi although effectiveness is dependent on light purity, energy levels and microbial genus.

SIGNIFICANCE AND IMPACT OF THE STUDY

Light from two arrays of different blue LEDs significantly reduced bacterial (Leuconostoc mesenteroides, Bacillus atrophaeus and Pseudomonas aeruginosa) viabilities. Significant in vitro viability loss was observed for the filamentous fungi, Penicillium digitatum and Fusarium graminearum when exposed to pure blue light only plus a photosensitizer. F. graminearum viability was significantly reduced by blue light alone. Results suggest that (i) the amount of significant loss in bacterial viability observed for blue light that is pure or with traces of other wavelengths is genus dependent and (ii) depending on fungal genera, pure blue light is fungicidal with or without a photosensitizer.

Antibiotic overuse and resistance in dermatology

Antibiotics have a significant role in dermatology, treating a wide range of diseases, including acne, rosacea, inflammatory skin conditions and skin structure infections, such as cellulitis, folliculitis, carbuncles, and furuncles. Because of their consistent use, utility, and availability, antibiotics are susceptible to overuse within the medical practice, and, specific to this discussion, in the dermatologic setting. The issue of continuously increasing risk of antibiotic resistance remains an important concern to the dermatologist. The scope of this review will be to provide an overview of the common antibiotics used in the dermatologic setting with an emphasis on identifying areas of overuse, reported bacterial resistance, and discussion of clinical management aimed at decreasing antibiotic resistance.

"Hot tub" Folliculitis from a nonchlorinated children's pool

Pseudomonas aeruginosa is common cause of folliculitis following contact with contaminated water. We report a case of pseudomonal folliculitis that occurred after swimming in a children's pool filled with water from a well.

Pseudomonas skin infection: clinical features, epidemiology, and management

Pseudomonas aeruginosa is a Gram-negative bacillus that is most frequently associated with opportunistic infection, but which can also present in the otherwise healthy patient. The range of P. aeruginosa infections varies from localized infections of the skin to life-threatening systemic disease. Many P. aeruginosa infections are marked by characteristic cutaneous manifestations. The aim of this article is to provide a comprehensive synthesis of the current knowledge of cutaneous manifestations of P. aeruginosa infection with specific emphasis on clinical features and management. The ability of P. aeruginosa to rapidly acquire antibacterial resistance is an increasingly well recognized phenomenon, and the correct application of antipseudomonal therapy is therefore of the utmost importance. A detailed discussion of currently available anti-pseudomonal agents is included, and the benefits of antimicrobial combination therapy versus monotherapy are explored. Rapid clinical recognition of P. aeruginosa infection aided by the identification of characteristic cutaneous manifestations can play a critical role in the successful management of potentially life-threatening disease.

Aquatic sports dermatoses: part 1. In the water: freshwater dermatoses

The first of this three-part series on water-related dermatoses involving the athlete will include sports occurring with the majority of time spent in the water. These sports include swimming, diving, scuba, snorkeling and water polo. Numerous authors have described dermatologic conditions commonly seen in swimmers. This series provides an updated and comprehensive review of these water dermatoses. In order to organize the vast number of skin conditions related to water exposure, we divided the skin conditions into groupings of infectious and organism-related dermatoses, irritant and allergic dermatoses and miscellaneous dermatoses. The vast majority of skin conditions involving the water athlete result from chemicals and microbes inhabiting each environment. When considering the effects of swimming on one's skin, it is also useful to differentiate between exposure to freshwater (lakes, ponds and swimming pools) and exposure to saltwater. This review will serve as a guide for dermatologists, sports medicine physicians and other medical practitioners in recognition and treatment of these conditions.

[Infections related to recreational waters]

Recreational waters are a source of infection by several microorganisms causing acute gastrointestinal, cutaneous and respiratory illnesses. Cryptosporidium, noroviruses and enteropathogenic Escherichia coli strains are the most important causes of diarrhea, while Pseudomonas and Staphylococcus aureus are the main causes of cutaneous infections, and Legionella is the major cause of acute lower respiratory disease. Approximately 90% of outbreaks occur in treated recreational waters (swimming pools, spas and recreational parks), while the remaining 10% arise from natural waters used for leisure (bathing in rivers, beaches, etc). In spas, most infections are caused by thermophilic bacteria, such as Pseudomonas and Legionella, since overgrowth of these bacteria is facilitated by the direct effect of temperature and, indirectly, by the evaporation of the disinfectant. Outbreaks related to recreational waters usually reflect deficient control of the system: a low level of disinfectant, or the use of an inappropriate disinfectant, insufficient maintenance and cleaning of the installation, higher than recommended usage, and failure of the disinfectant dosage system. The correct design, maintenance and use of these facilities drastically lower the risk of infections from recreational waters. Thus, other key actions to minimize this risk are the existence of, and compliance with, regulatory rules, as well as educational campaigns on good hygiene practices directed at users. Rapid etiologic diagnosis of affected patients, together with an epidemiological survey and detection of the pathogen implicated in water samples are the keys to outbreak control.

Neutrophilic dermatoses in children

The neutrophilic dermatoses are rare disorders, especially in children, and are characterized by neutrophilic infiltrates in the skin and less commonly in extracutaneous tissue. The neutrophilic dermatoses share similar clinical appearances and associated conditions, including inflammatory bowel disease, malignancies, and medications. Overlap forms of disease demonstrating features of multiple neutrophilic dermatoses may be seen. The manuscript attempts to provide an up-to-date review of (i) classical neutrophilic dermatoses, focusing on distinctive features in children and (ii) neutrophilic dermatoses which may largely be pediatric or genodermatosis-associated (Majeed, SAPHO [synovitis, severe acne, sterile palmoplantar pustulosis, hyperostosis, and osteitis] syndrome, PAPA (pyogenic sterile arthritis, pyoderma gangrenosum, and acne), PFAPA (periodic fever with aphthous stomatitis, pharyngitis, and cervical adenopathy), and other periodic fever syndromes, and congenital erosive and vesicular dermatosis healing with reticulated supple scarring).