Keiko Okuma

Dissemination of New Methicillin-Resistant Staphylococcus aureus Clones in the Community

ABSTRACT Multiple methicillin-resistant Staphylococcus aureus (MRSA) clones carrying type IV staphylococcal cassette chromosome mec were identified in the community-acquired MRSA strains of both the United States and Australia. They multiplied much faster than health-care-associated MRSA and were resistant to fewer non-beta-lactam antibiotics. They seem to have been derived from more diverse S. aureus populations than health-care-associated MRSA strains.

Novel Type V Staphylococcal Cassette Chromosome mec Driven by a Novel Cassette Chromosome Recombinase, ccrC

ABSTRACT Staphylococcal cassette chromosome mec (SCCmec) is a mobile genetic element composed of the mec gene complex, which encodes methicillin resistance, and the ccr gene complex, which encodes the recombinases responsible for its mobility. The mec gene complex has been classified into four classes, and the ccr gene complex has been classified into three allotypes. Different combinations of mec gene complex classes and ccr gene complex types have so far defined four types of SCCmec elements. Now we introduce the fifth allotype of SCCmec, which was found on the chromosome of a community-acquired methicillin-resistant Staphylococcus aureus strain (strain WIS [WBG8318]) isolated in Australia. The element shared the same chromosomal integration site with the four extant types of SCCmec and the characteristic nucleotide sequences at the chromosome-SCCmec junction regions. The novel SCCmec carried mecA bracketed by IS431 (IS431-mecA-ΔmecR1-IS431), which is designated the class C2 mec gene complex; and instead of ccrA and ccrB genes, it carried a single copy of a gene homologue that encoded cassette chromosome recombinase. Since the open reading frame (ORF) was found to encode an enzyme which catalyzes the precise excision as well as site- and orientation-specific integration of the element, we designated the ORF cassette chromosome recombinase C (ccrC), and we designated the element type V SCCmec. Type V SCCmec is a small SCCmec element (28 kb) and does not carry any antibiotic resistance genes besides mecA. Unlike the extant SCCmec types, it carries a set of foreign genes encoding a restriction-modification system that might play a role in the stabilization of the element on the chromosome.

Insights on antibiotic resistance of Staphylococcus aureus from its whole genome: genomic island SCC

Staphylococci are ubiquitous colonizers of the skin and mucous membranes and Staphylococcus aureus is the most pathogenic species. The spread of antibiotic resistance among S. aureus strains is a major concern in the treatment of staphylococcal infections. Acquisition of resistance may involve mutation of a bacterial gene on the chromosome or transfer of a resistance gene from other organisms by some form of genetic exchange (conjugation, transduction, or transformation). Completion of whole genome sequences of three methicillin-resistant S. aureus (MRSA) strains has provided us a birds-eye view of the distribution of the mobile genetic elements in the bacterial chromosome that encode antibiotic resistance as well as pathogenicity in S. aureus.

Cell Wall Thickening Is a Common Feature of Vancomycin Resistance in Staphylococcus aureus

ABSTRACT We have previously shown that a thickened cell wall is responsible for the vancomycin resistance of vancomycin-resistant Staphylococcus aureus (VRSA) (equivalent to vancomycin-intermediate S. aureus and glycopeptide-intermediate S. aureus) strain Mu50 (L. Cui, H. Murakami, K. Kuwahara-Arai, H. Hanaki, and K. Hiramatsu, Antimicrob. Agents Chemother. 44:2276-2285, 2000). However, the mechanism of vancomycin resistance in other VRSA strains remained unclear. In this study, 16 clinical VRSA strains from seven countries were subjected to serial daily passage in drug-free medium. After 10 to 84 days of passage in the nonselective medium, passage-derived strains with decreased MICs of vancomycin (MIC, <4 mg/liter) were obtained. However, all of the passage-derived strains except one (15 of 16) still possessed subpopulations that were resistant to vancomycin as judged by population analysis, and vancomycin-resistant mutant strains were selected from the passage-derived strains by one-step vancomycin selection with a frequency of 4.25 × 10−6 to 1.64 × 10−3. The data indicated that vancomycin-resistant cells are frequently generated from the passage-derived strains even after vancomycin selective pressure is lifted. Cell wall thicknesses and MICs of glycopeptides (vancomycin and teicoplanin) and beta-lactams (imipenem and oxacillin) were determined for a total of 48 strains, including 15 sets of three strains: the clinical VRSA strain, the passage-derived strain, and the vancomycin-resistant mutant strain obtained from the passage-derived strain. No simple correlation between glycopeptide and beta-lactam MICs was seen, while significant correlations between MICs of vancomycin and teicoplanin (r = 0.679; P < 0.001) and between MICs of imipenem and oxacillin (r = 0.787; P < 0.001) were recognized. Moreover, all of the VRSA strains had significantly thickened cell walls, which became thinner with the loss of vancomycin resistance during drug-free passages and again became thick in the resistant mutant strains. The data showed that cell wall thickness had high correlation with the MICs of the two glycopeptides (correlation coefficients, 0.908 for vancomycin and 0.655 for teicoplanin) but not with those of the beta-lactam antibiotics tested. These results together with coupled changes of cell wall thickness and vancomycin MICs in 16 isogenic sets of strains indicate that thickening of the cell wall is a common phenotype of clinical VRSA strains and may be a phenotypic determinant for vancomycin resistance in S. aureus.

New trends in Staphylococcus aureus infections: glycopeptide resistance in hospital and methicillin resistance in the community.

Purpose of review Methicillin-resistant Staphylococcus aureus is prevalent in hospitals throughout the world, and we have got used to its presence in daily clinical practice. However, methicillin-resistant S. aureus has not remained static over the past four decades, but seems to be evolving in unfamiliar directions. This review focuses on recent findings on two directions of methicillin-resistant S. aureus evolution: the acquisition of multiple antibiotic resistance in the hospital and the trend towards methicillin-resistant S. aureus as a community pathogen. Recent findings We looked at reports on glycopeptide resistance in S. aureus and those on community-acquired methicillin-resistant S. aureus strains, with some references of historical value to explain the entire picture of this ‘new field’ of the methicillin-resistant S. aureus problem. Summary The references given here (excluding some of low credibility) attest the increasing awareness of the two conspicuous problems concerning methicillin-resistant S. aureus infection. One is the increasing trend of glycopeptide-resistance, making difficult the successful treatment of multi-drug-resistant methicillin-resistant S. aureus infection in the hospital. On the other hand, non-multi-drug-resistant methicillin-resistant S. aureus strains are emerging as novel threats in the community, the genetic analysis of which indicates that they are independent clones from those found in hospitals.

Therapeutic depletion of myeloid lineage leukocytes in patients with generalized pustular psoriasis indicates a major role for neutrophils in the immunopathogenesis of psoriasis

BACKGROUND Generalized pustular psoriasis (GPP) is a chronic autoimmune disease characterized by fever, erythema, and neutrophilic pustules over large areas of the skin. GPP does not respond well to pharmacologic intervention. OBJECTIVE We sought to assess efficacy of selectively depleting the myeloid lineage leukocytes in patients with GPP. METHODS Fifteen patients with persistent moderate to severe GPP despite conventional therapy were included. Eligible patients had more than 10% of their skin area covered by pustules. Treatment with oral etretinate, cyclosporine, methotrexate, prednisolone, and topical prednisolone/vitamin D3 was continued if had been initiated well in advance of study entry. Five sessions of adsorptive granulocyte and monocyte apheresis (GMA) with the Adacolumn (JIMRO Co Ltd, Takasaki, Japan) were administered (1 session/wk over 5 weeks) to selectively deplete Fcγ receptor and complement receptor bearing leukocytes. Efficacy was assessed by measuring the skin areas covered by pustules at baseline and 2 weeks after the last GMA session. RESULTS One patient did not complete the first GMA session. Based on the GPP severity scores relative to entry, the overall scores improved (n = 14, P = .0027), and the area of erythroderma (P = .0042), pustules (P = .0031), and edema (P = .0014) decreased. Likewise, Dermatology Life Quality Index improved (P = .0016), reflecting better daily function and quality of life. Twelve patients were judged as responders (85.7%), and 10 patients maintained the clinical response for 10 weeks after the last GMA session without any change in medication. LIMITATIONS This study was unblinded and without a placebo arm. CONCLUSION GMA in this clinical setting was safe and effective, suggested a major role for granulocytes/monocytes in the immunopathogenesis of GPP.

A case report of steroid and immunosuppressant-resistant pyoderma gangrenosum successfully treated by granulocytapheresis

Abstract:  Granulocytapheresis (GCAP) therapy is a newly developed therapeutic modality for inflammatory bowel diseases such as ulcerative colitis and Crohns disease. Pyoderma gangrenosum (PG) is a chronic inflammatory skin disease characterized by the appearance of erythematous macules and plaques with pustules or nodules that rapidly progress to ragged, undermined multiple ulcers. We attempted GCAP therapy in a patient with PG resistant to prednisolone and various other immunosuppressants. GCAP therapy was initiated at three‐ to four‐day intervals and a good response from all skin lesions, with eventual total epithelialization, was observed after 10 sessions of this therapy. Furthermore, circulating levels of inflammatory cytokines such as interleukin‐8 (IL‐8) and granulocyte colony stimulating factor (G‐CSF) also decreased after the GCAP therapy. Our results suggest that GCAP is a safe and useful tool for the treatment of intractable PG, and that IL‐8 and G‐CSF are likely to be involved in the pathogenesis of PG.

Granulocyte and monocyte adsorption apheresis for generalized pustular psoriasis

Granulocyte and monocyte adsorption apheresis (GCAP) is an extracorporeal circulation therapy that removes activated granulocytes and monocytes. GCAP was initially approved for the treatment of ulcerative colitis, which is attributed to activated granulocytes and macrophages that infiltrate the target tissues. Generalized pustular psoriasis (GPP) is also supposed to be caused by activated neutrophils. In this study, we treated two patients with refractory GPP by using GCAP. Patient 1, a 68‐year‐old woman who had liver cirrhosis, underwent seven GCAP sessions. Patient 2, a 26‐year‐old woman who had systemic lupus erythematosus and had been treated with systemic corticosteroids, underwent eight GCAP sessions. In both patients, GCAP resulted in an immediate improvement in skin lesions and fever reduction, without any adverse effects. We suggest that GCAP is an effective therapy for refractory GPP.

Benign symmetrical lipomatosis associated with alcoholism

Dear Editor, Benign symmetrical lipomatosis is a rare disorder characterized by fat distribution in the shoulders, arms and neck in the context of chronic alcoholism. Over a period of years, the fat deposits grow to a large size, become cosmetically deforming and, in advanced cases, cause dyspnea. A 42-year-old man presented with multiple, large, symmetrical masses in his neck, shoulders and upper arms that had enlarged progressively for the previous 4 years (Fig. 1). The patient complained of discomfort and a deteriorating range of neck motion. Moreover, he complained of difficulty finding clothes that fit his neck and shoulders. Subcutaneous veins around the neck were remarkably distended up. Magnetic resonance imaging confirmed the presence of large masses of subcutaneous fat tissue infiltrating the surrounding tissue (Fig. 2). Biopsy showed lipomas histologically. Routine laboratory blood tests including electrolytes, glucose and a complete blood count were within normal limits. Abdominal echography showed no additional information such as fatty liver or liver cirrhosis. His past history was unremarkable, although he had been a heavy drinker for 20 years. According to these clinical findings, our patient was diagnosed with benign symmetrical lipomatosis. At first, we advised him to avoid drinking, although abstinence from alcohol does not reverse the progression of the disease. Surgical excision was performed bilaterally at the shoulders. However, it was difficult to remove all of the lesions because the external jugular vein and some nerves were located in proximity to these lesions. Benign symmetrical lipomatosis is characterized by diffuse deposits of fat arranged symmetrically around the neck, shoulders and upper extremities. It is more frequent in middle-aged men who have a history of decades of heavy alcohol consumption. This condition is also known as Madelung disease. This uncommon disease predominantly affects men between the ages of 30 and 60 years. It is assumed to be a discrete malfunction in fat metabolism

Acne conglobata successfully treated by fractional laser after CO2 laser abrasion of cysts combined with topical tretinoin

Dear Editor, Acne conglobata is characterized by the presence of nodulocystic lesions. Conservative therapy with oral and topical antibiotics is usually ineffective. On the other hand, surgical excision is difficult for facial lesions. We applied a CO2 laser to open cysts, fistulas and abscesses, and drained the acne conglobata sinuses, as previously reported. Although discharge of malodorous pus ceased after the CO2 laser treatment, numerous concave scars persisted. Therefore, we additionally treated the patient with a fractional laser. A 21-year-old man presented with severe acne lesions on his face which he had suffered with since his teens. Physical examination revealed a number of nodulocystic lesions with underlying draining abscesses and sinus tracts (Fig. 1a). The lesions had increased in both size and number despite various treatments. He was diagnosed as having acne conglobata. We applied short-pulsed CO2 laser therapy (Lumenis Laser 30C; Nihon Lumenis, Tokyo, Japan) for ablation of the cysts. Under local anesthesia with lidocaine, the cysts were opened along their major axes, and the contents such as keratin and pus were removed. Then, the covering cyst wall was ablated by vaporization using the laser at a power setting of 3 W in continuous wave mode to expose the floor epithelium (Fig. 1b). The treatment was repeated once every 2 weeks. At the same time, the patient started be treated with topical 0.1% tretinoin cream once a day to prevent the appearance of new acne lesions. At 3 months after the start of this laser treatment, the number of cystic lesions had decreased markedly. However, numerous concave scars remained (Fig. 1c). Thus, we additionally applied a fractional laser (Reliant Fraxel SR Laser, Reliant Technologies, Palo Alto, CA, USA), which delivers multiple microscopic laser beams under computerized control. Under local anesthesia with 10% lidocaine cream, one treatment consisted of six passes to attain a final microscopic injury with a density of 1500/cm. The fluency was set to 16 mJ. The treatment was repeated up to seven times at intervals of 4 weeks. At follow up after 6 months without treatment, good cosmetic results were noted and there were no recurrences (Fig. 1d,e). This clinical study was conducted with informed consent from the patient. The symptoms of acne conglobata, such as inflammation and malodorous discharge, do not resolve without removal of the lesions. However, there are no indications for surgical excision of larger facial cysts, because they usually require skin grafting. Thus, we vaporized the covering cyst wall using a CO2 laser, to expose the floor epithelium. Moreover, we also treated the patient with topical tretinoin, not only to prevent increasing in the number of acne lesions but also to reduce the risk of pigmentation and scarring. As a result, the sinuses disappeared with persistence of concave scarring. Although the patient was satisfied with disappearance of the malodorous discharge, we treated the scars with a fractional laser, which was reported to be effective for acne scars, in an effort to elevate the concave scars. It is thought that fractional laser induces remodeling of upper dermis around the microscopic epidermal defects in scars. The combination of a CO2 laser and fractional laser was found to produce clinical improvement in