Natasha Press, MD, FRCPC (biography and disclosures)
What I did before
A 32 year old woman, otherwise healthy, presented with a “spider-bite”. On exam, she had a tender abscess on her buttock. It was associated with some surrounding cellulitis but no fever or other systemic features. I recommended incision and drainage, but she wasn’t keen on it, so I gave her a 7-day prescription for cephalexin (keflex) 500 mg po qid.
What changed my practice
The woman returned to the office 1 week later. The abscess had increased in size and another one had appeared on her labia. She was in significant discomfort and reported no improvement with the cephalexin. Incision and drainage of her abscesses were done, and the culture result from the swab showed community-associated methicillin resistant Staphylococcus aureus (ca-MRSA). This patient did not improve because her abscesses were caused by ca-MRSA which is resistant to cephalexin and other beta-lactam antibiotics. As well, an incision and drainage should have been done when she initially presented.
Abscesses caused by ca-MRSA are often multiple, appearing on the buttock and groin, as well as other parts of the body. Treatment includes incision and drainage, with the addition of antibiotics if the abscess is large or there is surrounding cellulitis, incomplete drainage, or fever [1] Oral antibiotics effective against ca-MRSA usually include septra, doxycycline, and clindamycin.
If a patient presents with cellulitis associated with an abscess or wound, there is a greater chance that it could be due to ca-MRSA (cellulitis by itself, without any abscess/wound, is usually due to Group A Streptococcus). In these cases, ca-MRSA should be covered empirically, but Group A Streptococcus should be covered as well. Unfortunately, the antibiotics effective against ca-MRSA (septra, doxycycline, clindamycin) are not reliable for treatment of Group A Streptococcus [2]. Many doctors, therefore, will prescribe both cephalexin to cover Group A Streptococcus, as well as septra or doxycycline to cover the ca-MRSA.
What I do now
Now, when I see a patient like the woman in this case, I incise and drain the abscesses and prescribe septra 1 DS tablet po bid and cephalexin 500 mg po qid for 5-14 days.
Key learning points:
- Think of ca-MRSA in any patient presenting with an abscess and associated cellulitis.
- Perform incision and drainage of the abscess at the time of presentation. Outline to patients this is important for improved outcomes.
- Initiate empiric antibiotics which cover Group A Strep (eg. cephalexin) AND ca-MRSA (eg. septra, doxycycline, or clindamycin)
- Counsel patients about strategies to reduce exposure to family members. I recommend that they cover the abscesses/wound, and wash their hands frequently.
- Recurrences of ca-MRSA are common and frustrating. If a recurrence develops, they should have incision and drainage and receive an antibiotic which covers ca-MRSA.
References: (Note: Direct article downloads and article requests require a login ID with the BC College of Physicians website)
[1] Moellering, RC Jr. Clin Infect Dis 2008:46:1032-7. (Article Request Form)
[2] Tan K, Romney M, Champagne S. AMMI, 2008
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Excellent review and differentiation between management of pure cellulitis versus cellulitis with abscess formation to ensure coverage of ca-MRSA.
Great advice. In patients with multiple recurrences, do you ever recommend fucidin ointment application to the patients’ nares.
I deal with regular MRSA outbreaks in Nunavut, especially Arviat, where there is serious overcrowding, no running water and therefore very difficult to practice good hygiene, Moreover compliance is generally poor. There are months that no MD is on site and all MD consults are per telephone with RN’s in an expanded role or if lucky a certified NP. Many of the RN’s are reluctant to do an I&D because that is not in their scope of practice. The “solution” has been to use clindamycin iv 600mgm q 8 h or if shortstaffed 900mgm q 12 hours. That seems to work most of the time, but I am afraid of resistance and of course the negative side effects, even though so far that has not occurred. Any advice?
Most abscesses have some surrounding erythema, but require only I&D- ie. no antibiotics. Using two antibiotics would be overkill for the vast majority of these infections. Next topic: how to treat the C.difficile.
Does everyone feel the abscess needs to be “pointing”, if its not ie.in the very early stages would using 2 antibiotics be just as good?
The reason that we have MRSA is due to the indiscriminate use of antibiotics. If it is a simple abscess, I found I&D works quite well without resorting to any antibiotics. During my first 2 months in NWT in the 70’s, I nearly did I & D every day for 2 months till I got the hygiene improved. I did not resort to antibiotics then nor now.
I agree with the author
We seldom saw any cases, but the incidence seems to be on the rise
Thus need intensive therapy from the start
After discussions in my clinical group, we’ve been using a combination of Septra and Keflex whenever we were concerned about MRSA. I’m glad to hear that this is a generally accepted approach.
Itsy bitsy spiders don’t bite. Once upon a time all docs & patients accepted the spider bite explanation. They were convenient & quick scapegoats. These “bites” were strep or less virulent staph.
Then we started seeing more & more nasty bites (aka mRSa staph). The conversations take longer.
i keep a couple of key Inf disease / Er articles “don’t blame the spiders “to convince incredulous patients & sometimes colleagues.
I too would be concerned about overuse of antibiotics in this case. I guess, to me, the size of the cellulitis and how likely the patient is to follow up, would be important in deciding whether or not to use antibiotics or just I+D.
I believe that a more complex approach is warranted. Treatment with two antibiotics empirically is behavior that has caused this problem in the first place. I&D is usually adequate treatment HOWEVER if the lesion is on the face, hands or is in a child, or poor followup is likely then empiric treatment is warranted. Nearly 60% of skin cultures at our lab are now MRSA for outpatients. There should also be some discussion of how to manage recurrences as they are frequent and an entirely different approach is then needed. A standardized written handout for how to minimize recurrence and spread in family and school is also very useful.
Any tender red inflamed skin lesion should evoke a suspicion of an infection particularly by MRSA. I&D is done if indicated and swab sent for C&S and cover with antibiotics, septra and cephalosporins. Always advise local antiseptic care and precautions.
For caMRSA the advice I follow is SeptraDS 2 tablets bid and rifampin600 mg od.
First I’d like to respond to comments on I&D alone versus adding antibiotics. I&D has been recognized as the primary therapy for cutaneous abscesses since the era before antibiotics. The role of adjunctive antibiotic therapy for MRSA uncomplicated abscesses remains incompletely defined. Observational studies have shown that some individuals do benefit from adding antibiotics, but data from rigorous clinical trials are lacking. Until these data become available, we rely on expert opinion which recommends adding antibiotics in certain clinical scenarios such as significant surrounding cellulitis, fever, immunosuppression/comorbidities, location of the abscess in an area that may be difficult to drain completely (e.g. central face), and failure to respond to I&D alone [1].
Second, I’d like to respond to choice of antibiotic. Most ca-MRSA strains are susceptible to septra, doxycycline, clindamycin, and the choice of antibiotic depends on many factors, e.g. is the patient a child? allergies? However, there are geographical differences in resistance and it’s important to know your local susceptibility patterns. Our local data show that 65% of our ca-MRSA isolates and 73% of our Group A Streptococcus are susceptible to clindamycin. That means if I empirically use clindamycin, I would have approximately a 30% chance of not covering the MRSA or Group A Streptococcus. However, if an available culture shows that the causative organism is MRSA and is susceptible to clindamycin, then it would be a good choice. For clindamycin, our lab does a test called a D-test to determine if there is inducible resistance (in erythromycin-resistant isolates), which is important to confirm that clindamycin will work. I use septra and keflex empirically because our data shows almost 100% susceptibility for ca-MRSA and Group A Streptococcus respectively [2]. Therefore, it’s useful to know your local susceptibility patterns.
With respect to septra plus rifampin, it is important to note that rifampin should never be used alone as monotherapy because resistance emerges rapidly. There are no data to support using this combination over septra alone [3], but sometimes I do use both in certain clinical situations.
A concern with using topical fusidic acid is that resistance develops rapidly with fusidic acid monotherapy. Using topical fusidic acid for skin conditions appears to be a major driver of resistance in Staphylococcus aureus, including MRSA. Potentially, if topical fusidic acid use causes a significant amount of resistance, this would limit our ability to use systemic fusidic acid to treat invasive MRSA infections [4].
Third, I’d like to respond to comments regarding decolonization of patients, particularly if they’ve had multiple recurrences of MRSA infection. To date, there are no data to support routine decolonization with nasal mupirocin ointment and chlorhexidine body washes in the community setting. However, I will sometimes offer a short-course decolonization regimen to a patient who has had multiple recurrences and where there is ongoing transmission in a household. Hygiene and wound care remain the cornerstones of primary prevention [5].
1. Gorwitz RJ, Clin Inf Dis 2007: 44: 785
2. Tan K, et al. AMMI, 2008.
3. Moellering, RC. Clin Inf Dis 2008: 46: 1032-7.
4. Howden BP and Grayson ML. Clin Inf Dis 2006:42: 394.
5. Gorwitz, RJ, Jernigan, DB, Powers, JH, et al. Strategies for clinical management of MRSA in the community: Summary of an experts’ meeting convened by the Centers for Disease Control and Prevention. 2006. Available at: http://www.cdc.gov/ncidod/dhqp/pdf/ar/CAMRSA_ExpMtgStrategies.pdf.
Cellulitis with abscesss without fever requires I&D and withhold antibiotics and await C&S with close F/U.
With fever , blood cultures and po antibiotics Bactrim, clinda, doxy for 48 hrs . If worse clinically consider IV Vanco or Daptomycin for CA-MRSA.
Please don’t prescribe Septra DS unless you (or your horse) have managed to swallow these gargantuan suckers!
What a great resource!
One of the biggest problems for special needs and elderly patients in hospitals, who can’t tell doctors how they feel, is the nurses leaving their wounds OPEN in the hosptial, while they’re getting treatment, thus exposing the site to more infection! Hospitals need to remind their nurses and CNAs to wash and scrub the patient with MRSA and keep the bedding cleaned! Or the patient will end up coming back with a worse infection! Cover the darn wounds! Wash your hands. Change the bedding. And feed healthy foods while in hospital to help the body heal. And plenty of fluids! Even a banana bag helps the body fight off hte MRSA>
I think it is also important not to dismiss how painful cellulitis/abscesses are, patients are going to be resistant even to the idea of a needle stick with lidocaine into this already extremely painful area. I&D is going to be a much easier sell if patients are given an injection of benzodiazepine or narcotic first, and more likely to seek future treatment early on if they are not traumatised. I would only forgo follow up antibiotics if the abscess was recently formed.