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Clinical Updates

Dany Nassar, MD

Minimizing the Spread of Recurrent Furunculosis

Dany Nassar

Wednesday, August 12, 2009

A furuncle ("boil") is a deep-rooted infectious inflammatory nodule that develops in and around a hair follicle, secondary to a Staphylococcus aureus infection.1 Lesions might be superficial or deeper (furuncle) or even evolve into a large abscess.

Folliculitis Folliculitis
(Taken from the image library on www.DermQuest.com)

There are three major problems that can be encountered during the management of furunculosis: the virulence of the strain, the recurrence of the furuncolosis, and community acquired methicillin-resistant S. aureus (CA-MRSA).

The virulence of S. aureus is mainly determined by the secretion of a toxin by the organism, known as the Panton-Valentine leukocidin (PVL). It is coded by the lukS-lukF gene and is responsible for severe necrotizing skin abscesses. Rare fatal complications have been reported, and include necrotizing pneumonia, brain abscess, bacteremia and endocarditis.2 In a recent study, lukS-lukF-positive S. aureus was found in 42% of patients with furunculosis and was associated with epidemic cases.3 Some studies reported the same prevalence of PVL in furunculosis4, while others had much higher prevalence.5 It depends on the population (hospital, community), on the definition of furunculosis (confusion with other diagnoses: abscess, carbuncle, deep folliculitis, etc). The virulence of S. aureus depends also on other factors such as Protein A, host defenses, etc. In the same study, nasal carriage was found in 58% of patients who had a superficial skin infection,3 including impetigo and furunculosis. Nasal carriage was associated with recurrent furunculosis.

Outbreaks of CA-MRSA have been reported worldwide, particularly in the USA. In a 2004 study of adult patients with purulent skin and soft tissue infections presenting to emergency departments in 11 American cities, methicillin-resistant S. aureus (MRSA) was isolated from 59% of lesions overall.6 The predominant clone is USA300, which harbors the mecA gene that confers the resistance to methicillin, and the PVL gene. Risk factors for CA-MRSA infections include direct contact with infected patients, colonized subjects, contaminated environment, crowding, sharing personal items, and direct contact activities.7 Unlike hospital-acquired MRSA, CA-MRSA harbors the PVL coding gene and can cause necrotizing skin infections. In the management of patients with recurrent furunculosis, these problems should be kept in mind.

Treatment of an Acute Episode

During treatment of an acute episode, surgical drainage, with direct examination and culture, is crucial in all suppurative lesions. Local treatment with an antiseptic solution and a dry dressing should be applied. Finally, systemic antibiotic treatment should also be given to those with disseminated furunculosis, carbuncles, severe surrounding cellulitis, and facial Staphylococcal infections or in immunocompromized patients.

For methicillin-sensitive S. aureus skin infections, the treatment of choice is a penicillin M (dicloxacillin, cloxacillin) or amoxicillin clavulanate (AMOX-CLAV). In penicillin-allergic patients, clindamycin or fusidic acid can be used. For MRSA infections, oral clindamycin, doxycycline (and less frequently minocycline), rifampicin (in association with other agents), and rarely oral fusidic acid could be used (see table one below).

In severe, necrotizing soft-tissue infections, and in geographical areas of high prevalence of MRSA, the role of this pathogen should be suspected and culture and sensitivity testing should be performed to guide which antibiotics to treat the patient with and the treatment must target this agent.

Table 1. Oral Agents For Treating CA-MRSA Soft-Tissue Infections


Antibiotic Dosage (adult)

Cost (€/day)8

Doxycycline       100 mg bid                   0.56
Clindamycin 600 mg every 6-8 hours   3.22
Rifampicin 600 mg every day, associated with
other antibiotics
 1.16
Linezolid 400-600 mg bid  10

In disseminated severe infections, parenteral antibiotics can be required. Food and Drugs Administration (FDA)-approved agents for CA-MRSA include the following: vancomycin, daptomycin, linezolid and tigecycline. Characteristics of these agents are presented in table two (see table two below).


Table 2. Parenteral Agents For Treatment of Severe CA-MRSA (FDA Approved)


Antibiotic    Dosage (adult) Administration 
Vancomycin   1 g every 12 hours iv
Daptomycin   4 mg/kg every 24 hours iv
Linezolid   600 mg every 12 hours  iv
Tigecycline

  100 mg once, than 50 mg every 12  hours

iv

Topical antibiotics such as mupirocin, fusidic acid and the recently developed drug retapamulin should be used with caution, because of the risk of selection of resistant strains. In our practice, they are reserved for superficial skin infections (impetigo, secondary infected dermatosis). In recurrent furunculosis, they are used for nasal decolonization.

Prevention of Recurrences

In identifying underlying diseases and risk factors in children, recurrent folliculitis and furunculosis might be a sign of genetic diseases with abnormal host defenses. In otherwise healthy adults, screening for diabetes should be performed. Other predisposing factors include systemic and topical steroid treatment, immunosuppressive treatments, organ transplant patients, HIV and obesity. Risk factors associated with recurrent furunculosis include nasal colonization with S. aureus, contact with persons having recurrent furunculosis, and people who have a chronic skin disease.             

Steroid folliculitis Steroid folliculitis
(Taken from the image library on www.DermQuest.com)


Recommendations for Minimizing the Spread of S. Aureus

A well-documented and successful control of an outbreak of CA-MRSA furunculosis in a German village has been published recently.9 Decolonization measures were applied on patients who experience a current furuncle or relapsing furunculosis, and their close contacts, as well as those who were colonized with S. aureus.

Decolonization measures include the following:

  • Treatment with mupirocin nasal ointment three times daily for 5 days
  • Hand disinfection with an alcohol-based antibacterial hand sanitizer after applying nasal ointment
  • Daily disinfection of personal items (for example: comb, razor, glasses, and jewelry) and the bathtub or shower floor with an alcohol-based antimicrobial cleanser
  • Daily changing and washing (in water with a temperature of at least 60°C, using a laundry detergent) of towels, bedclothes, underwear, and clothing, daily treatment of skin and hair with an octenidin-based wash solution
  • Antiseptic treatment of the throat by gargling with 0.1% chlorhexidine solution three times daily

For patients with recurrent furunculosis, the following is recommended:

  • A nasal swab should be performed to screen the sites of colonization in patients and their contact persons
  • Patients are advised to follow stringent decontamination measures (listed above), as well as those people who have been in close contact with them
  • Sequential nasal decontamination using mupirocin ointment (administered for 5 consecutive days, each month) can be useful for long-term nasal decontamination. Fusidic acid ointment could also be used for this purpose
  • Decontamination failure could be due to S. aureus resistance to mupirocin. In these cases, a nasal swab should be repeated to determine a S. aureus antibiotic susceptibility profile
  • Retapamulin is a new topical antibiotic that is active on resistant strains. It needs to be validated in this indication; and
  • Use of oral antibiotics (such as, rifampicin, doxycycline) to minimize nasal carriage should be avoided, in order to prevent development of resistant strains

In conclusion, incision and drainage of purulent skin lesions and education of patients on strategies to prevent further transmission are the major components of management of recurrent furunculosis. MRSA has emerged as a frequent cause of skin and soft-tissue infections in the community, with strains that possess virulence factors. Further research is needed for specific prevention methods and treatment of CA-MRSA.

References

  1. Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft-tissue infections. Clin Infect Dis. 2005;41:1373-1406.
  2. Bahrain M, Vasiliades M, Wolff M, Younus F. Five cases of bacterial endocarditis after furunculosis and the ongoing saga of community-acquired methicillin-resistant Staphylococcus aureus infections. Scand J Infect Dis. 2006;38:702-707.
  3. Durupt F, Mayor L, Bes M, et al. Prevalence of Staphylococcus aureus toxins and nasal carriage in furuncles and impetigo. Br J Dermatol. 2007;157:1161-1167.
  4. Yamasaki O, Kaneko J, Morizane S, et al. The association between Staphylococcus aureus strains carrying panton-valentine leukocidin genes and the development of deep-seated follicular infection. Clin Infect Dis. 2005;40:381-385.
  5. Couppie P, Cribier B, Prévost G. Leukocidin from Staphylococcus aureus and cutaneous infections: an epidemiologic study. Arch Dermatol. 1994;130:1208-1209.
  6. Moran GJ, Krishnadasan A, Gorwitz RJ, et al. Methicillin-resistant S. aureus infections among patients in the emergency department. N Engl J Med. 2006;355:666-674.
  7. Stryjewski ME, Chambers HF. Skin and soft-tissue infections caused by community-acquired methicillin-resistant Staphylococcus aureus. Clin Infect Dis. 2008;46:S368-77.
  8. The 2008 VIDAL Drug Compendium, 84th Edition. London: CMP-Medica.
  9. Wiese-Posselt M, Heuck D, Draeger A, et al. Successful termination of a furunculosis outbreak due to lukS-lukF-positive, methicillin-susceptible Staphylococcus aureus in a German village by stringent decolonization, 2002-2005. Clin Infect Dis. 2007;44:e88-95.        
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