On-line version ISSN 1806-4841
An. Bras. Dermatol. vol.84 no.5 Rio de Janeiro Sept./Oct. 2009
Fernanda RazeraI; Sabrina De StefaniII; Renan Rangel BonamigoIII; Gislaine Silveira OlmIV; Cícero Armídio Gomes DiasV; Gabriel Azambuja NarvaezVI
IMaster in epidemiology. Dermatologist,
Service of Dermatology, Hospital Mãe de Deus - Porto Alegre (RS), Brazil
IIMaster studies under progress, Graduate Program in Pathology, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA). Dermatologist, Service of Dermatology, Hospital Mãe de Deus - Porto Alegre (RS), Brazil
IIIPh.D. in Medical Sciences, Universidade Federal do Rio Grande do Sul (UFRGS). Head of the Service of Dermatology, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA) and Service of Dermatology, Hospital Mãe de Deus - Porto Alegre (RS), Brazil
IVMaster studies under progress, Graduate Program in Hepathology, Universidade Federal de Ciências da Saúde de Porto Alegre(UFCSPA) Dermatologist, Service of Dermatology, Hospital Mãe de Deus - Porto Alegre (RS), Brazil
VPh.D. in Sciences (microbiology) - UFRJ. Joint Professor in Microbiology, Universidade Federal de Ciências da Saúde de Porto Alegre(UFCSPA) - Porto Alegre (RS), Brazil
VIInfectologist, Hospital Mãe de Deus - Porto Alegre (RS), Brazil
Methicillin-resistant Staphylococcus aureus (MRSA), particularly isolated at hospital setting, has been identified in cutaneous infections of community patients. This paper reports a case of furunculosis from the southern Brazil. Dermatologists must be attentive to this emergent etiological diagnosis. The isolated microorganism was subjected to PCR for gene mecA and to PCR for the gene that encodes the leukocidin of Panton-Valentine. These exams enabled genotypic identification of CA-MRSA.
Keywords: Furunculosis; Methicillin resistance; Staphylococcus aureus
Staphylococcus aureus is a bacterium commonly found on the skin and nasal cavity of the population. It is estimated that approximately 25 to 30% of the population carries this bacterium 1. Methicillin-resistant Staphylococcus aureus (MRSA) are the bacteria resistant to beta-lactam antibiotics (oxacillin, penicillin and amoxicillin). Initially, the infections were restricted to hospital environments 2.As of the 80s, the first cases of MRSA infection cases in patients who had no known predisposing factors were described. They were then named community acquired MRSA (or CA-MRSA). The first reports of CA-MRSA isolated in Latin America came from Porto Alegre in 2002 and 2003; out of three reported cases, two presented skin or soft part lesions 3.
As most infections caused by MRSA coming from the community are restricted to the skin and subcutaneous tissue, it is essential for the dermatologist to be knowledgeable in order to detect and manage this condition. The present study intended to report a case of a patient seen in the dermatological emergency department with pyodermitis caused by CA-MRSA.
Caucasian 32 year-old female patient, presented erythematous, infiltrate plaques with isolated pustule over the lesion on the right lower limb (thigh region), with local pain and redness. She presented similar but smaller lesion on the left leg. She reported no systemic symptoms, and had been treated as having been bitten by a spider. Previously healthy, she reported a c-section five months before the onset of the lesion. Her husband had similar lesions and had also received the same treatment, without satisfactory outcomes. Bacterioscopic and bacteriological tests of the pustules were performed and treatment was started with first generation cephalosporin for 14 days.
In the first week of treatment, the erythema regressed and she had furunculoid lesions (Figure 1). At the end of 14 days, there was total regression of the presentation. Antibiogram shower oxacillin resistant S. aureus sensitive to all other tested antibiotics (sulphamethoxazole-trimethopim, clyndamycin, erythromycin, gentamycin, ciprofloxacin and vancomycin), compatible with phenotypic characteristics of CA-MRSA.
The isolated microorganism was submitted to the following tests aiming at its genotypic characterization: PCR for gene mecA and determination of type of chromosome cassette, molecular typing by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST), in addition to PCR for likF-PV, which codifies leucocidin-Panton-Valentine. The presence of mecA was confirmed, inserted into SScmec type IV, and the gene that codifies exotoxin Panton-Valentine. The same presented molecular characteristics compatible with clone ST30 - OSPC (Oceania Southwest Pacific clone) (Figure 2).4
In view of the clinical findings, both phenotypic and genotypic, we diagnosed pyodermatis by CA-MRSA.
The prevalence of infections caused by CA-MRSA has been increasing 5. Purcell and Fergie demonstrated in 1990 that 2.9% of isolated S. aureus were methicillin resistant 5. In 2000, the prevalence increased to 19% and in 2003 to 62.4%. Other studies reported a prevalence of 53% of MRSA 6.
Clinical manifestations may range from simple skin lesions to septic shock. Skin impairment is the most prevalent one, which may reach 94% of the clinical manifestations resulting from infection caused by these bacteria 5,7,8. Abscesses and furunculosis are the most frequently related lesions 2,3,5,6,8. There are also cases of cellulitis, papules or erythematous nodules, plaques with crusts (impetigo) or the combination of these clinical presentations 6.
Resistance to methicillin occurs by the production of PBP2a, binding protein to penicillin that reduces the activity of most penicillins. PBP2a is codified by gene mecA carried by a mobile genetic element known as staphylococcal chromosome cassette (SCC). Currently, five types of SCCmec are known: I, II, III, IV and V. The three first ones are present predominantly in hospital MRSA, whereas the latter are found in the community 2,7,9. Because it is a small molecule, it is believed that mec IV can suffer easier dissemination than genetic elements carriers of mec I, II and III 1,2. SSmec IV codifies the resistance to only methicillin/ oxacillin and not to others non-beta lactam drugs.
Skin infections by CA-MRSA occur after the skin or nasal colonization of the host. Probably, CA-MRSA bacteria have virulence characteristics with greater adherence, resistance to some salts and to exotoxin leucocidin Panton-Valentine that enables it to prevail over commensal bacteria 2. Exotoxin PVL is lethal for neutrophils and it causes cell necrosis, causing a predilection for the skin and subcutaneous tissue. PVL is also associated with necrotizing pneumonia 2,7,10,11.
Patients without severe lesions, no history of exposure to nosocomial environments and sites of low prevalence may start treatment with penicillin resistant to penicillase (oxacillin) or first generation cephalosporin (cefazoline, cefalexine), whereas they wait for the results of the definite culture 2,12. For patients with less severe or chronic infections, it may be recommendable to wait for the results of the culture, optimizing treatment 2.
In case of lesions with purulent collections, the treatment of choice is drainage of abscesses, which may be a definite treatment in many cases 2,5,6,11.
Despite the presence of risk factors for MRSA identified in the previous history of the patient (c-section five months before the pyodermitis), there was suspicion of CA-MRSA owing to the resistance to other non-beta lactam antibiotics. In view of the genotypic characteristics that were found, the possibility of CA-MRSA was confirmed with this risk factor 4.
Owing to the difficulty to differentiate between infections acquired in the community or not and the increase of incidence, it is important to be attentive to the possibility, given that there is risk of progression to more severe infections.
The authors would like to thank Prof Agnes Figueiredo, from Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, for the molecular characterization of the sample.
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Conflict of interest: None
Financial funding: None
How to cite this article: Razera F, Stefani S, Bonamigo RR, Olm GS, Dias CAG, Narvaez GA. CA-MRSA em furunculose: relato de caso do sul do Brasil. An Bras Dermatol. 2009;84(5):515-8.