Increase in Community Acquired MRSA

[docB]

Ann Emerg Med. 2005 Mar;45(3):321-2.

High prevalence of methicillin-resistant Staphylococcus aureus in emergency department skin and soft tissue infections.

Frazee BW, Lynn J, Charlebois ED, Lambert L, Lowery D, Perdreau-Remington F.

Department of Emergency Medicine, Alameda County Medical Center-Highland Campus, Oakland, CA 94602, USA. bradf_98@yahoo.com

STUDY OBJECTIVE: We sought to determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) among emergency department (ED) patients with skin and soft tissue infections, identify demographic and clinical variables associated with MRSA, and characterize MRSA by antimicrobial susceptibility and genotype. METHODS: This was a prospective observational study involving a convenience sample of patients who presented with skin and soft tissue infections to a single urban public hospital ED in California. Nares and infection site cultures were obtained. A health and lifestyle questionnaire was administered, and predictor variables independently associated with MRSA were determined by multivariate logistic regression. All S aureus isolates underwent antibiotic susceptibility testing. Eighty-five MRSA isolates underwent genotyping by pulsed field gel electrophoresis, staphylococcal chromosomal cassette mec (SCC mec ) typing, and testing for Panton-Valentine leukocidin genes. RESULTS: Of 137 subjects, 18% were homeless, 28% injected illicit drugs, 63% presented with a deep or superficial abscess, and 26% required admission for the infection. MRSA was present in 51% of infection site cultures. Of 119 S aureus isolates (from infection site and nares), 89 (75%) were MRSA. Antimicrobial susceptibility among MRSA isolates was trimethoprim/sulfamethoxazole 100%, clindamycin 94%, tetracycline 86%, and levofloxacin 57%. Among predictor variables independently associated with MRSA infection, the strongest was infection type being furuncle (odds ratio 28.6). Seventy-six percent of MRSA cases fit the clinical definition of community associated. Ninety-nine percent of MRSA isolates possessed the SCC mec IV allele (typical of community-associated MRSA), 94.1% possessed Panton-Valentine leukocidin genes, and 87.1% belonged to a single clonal group (ST8:S). CONCLUSION: In this urban ED population, MRSA is a major pathogen in skin and soft tissue infections. Although studies from other practice settings are needed, MRSA should be considered when empiric antibiotic therapy is selected for such infections.

PMID: 15726056 [PubMed - indexed for MEDLINE]

This study has had a pretty big impact on the practice in my group. Most of us are now using Bactrim instead of Keflex for regular, non-IVDA, community acquired abscesses and culturing them. We never cultured these in residency and the rule used to be to not use antibiotics at all. Anyone else changing based on this?

[Apollyon]

We did a journal club on this (and related) articles recently - the one you mention is from Oakland, and we had two others, from Dallas/UTSW and from LA, and my program director was actually involved (but not enough to be listed as an author) in the Oakland study. Moreover, we are seeing an increased incidence of CA-MRSA (community acquired) in our locality, so we now are culturing them and giving abx (like Bactrim), neither of which we did even 6 months ago.

[pinbor1]

Originally Posted by Apollyon

We did a journal club on this (and related) articles recently - the one you mention is from Oakland, and we had two others, from Dallas/UTSW and from LA, and my program director was actually involved (but not enough to be listed as an author) in the Oakland study. Moreover, we are seeing an increased incidence of CA-MRSA (community acquired) in our locality, so we now are culturing them and giving abx (like Bactrim), neither of which we did even 6 months ago.

I have been treating them almost the same when it comes to the initial work up, unless they have risk factors for community acquired MRSA. The only change, I've made is to send wound cultures on all my I & D's. If the abscess looks bad, I'll start antibiotics keflex or augmentin. When they follow up for their wound check, the cultures can be checked and antibiotics can be changed or started as needed.

[docB]

Originally Posted by pinbor1

I have been treating them almost the same when it comes to the initial work up, unless they have risk factors for community acquired MRSA. The only change, I've made is to send wound cultures on all my I & D's. If the abscess looks bad, I'll start antibiotics keflex or augmentin. When they follow up for their wound check, the cultures can be checked and antibiotics can be changed or started as needed.

This is kind of what I used to do. I never did cultures but after residency I started giving Keflex. The problem with Keflex and Augmentin is that they have no activity against MRSA. That and no one in my pt population can afford Augmentin. Bactrim is a decent comprimise. The question is how much MRSA is there in the community in your area? Now that we've been doing cultures and keeping a half assed, nonscientific tally we've found lots of community MRSA even in people who don't have risk factors.

Perhaps, if you're using Keflex or Augmentin, and then switching after the cultures come back you should not give anything unless the cultures come back positive for MRSA. I don't know. Just an idea.

That's a good question. Is a MRSA abscess that has been properly I&Dd in a healthy person worse in terms of healing and recurrance than one with uaula skin flora? Does a healthy, post I&D patient necessarily need antibiotics just because it's MRSA? Hmmm... Gotta get on pubmed.

[Apollyon]

The UT-Southwestern study in pediatric patients showed that, even if the wrong antibiotic (ie, Keflex) was used, no antibiotic, Augmentin, IV abx, or whatever, they still, still healed up. Out of a little more than 100, 2 were admitted to the hospital, and (not surprisingly) what augured a worse outcome was the size of the abscess (>5cm, or 2 inches, which is HUGE on the thigh of a 2 year old). Even so, "worse outcome" is relative, since everyone got better.

[pinbor1]

Originally Posted by docB

Perhaps, if you're using Keflex or Augmentin, and then switching after the cultures come back you should not give anything unless the cultures come back positive for MRSA. I don't know. Just an idea.

That's a good question. Is a MRSA abscess that has been properly I&Dd in a healthy person worse in terms of healing and recurrance than one with uaula skin flora? Does a healthy, post I&D patient necessarily need antibiotics just because it's MRSA? Hmmm... Gotta get on pubmed.

Yeah, I usaully don't start antibiotics unless the abscess looks bad and they have comorbidities i.e. Diabetes.

Appolyon, I just took a look at the UTSW abstract. Haven't read the article yet, but I guess it wouldn't change my management when it comes to whether to start antibiotics. It seems like the CA-MRSA patients tended to do well with or without antibiotics post I&D. I guess the only limiting factor is that the study looks at pediatric populations. I didn't see any pubmed studies that looked at the same criteria in adults. hmm... That would be a nice study if it hasn't been done.

[LoZ]

Originally Posted by Apolloyn

Moreover, we are seeing an increased incidence of CA-MRSA (community acquired) in our locality, so we now are culturing them and giving abx (like Bactrim), neither of which we did even 6 months ago.

I'm not a docter by any means, but I did have CA-MRSA infection right above my left knee joint. It started as a boil of some kind, but it ended up swelling my entire knee area and I have a rather large skin abcess. When I went to the ER they performed I & D and immediatly prescribed me to Bactrim. I've been taking it for close to seven days and am seeing a great improvement in the healing process, and I've seen my doctor twice to make sure everything is fine. This is, apparently a somehwat odd infection. I gather from the postings I've read here and from what my physician and the doctors in the ER that MRSA has been on the rise in the CA, but was most typically thought to be in hospitals?

Originally Posted by pinbor1

It seems like the CA-MRSA patients tended to do well with or without antibiotics post I&D. I guess the only limiting factor is that the study looks at pediatric populations. I didn't see any pubmed studies that looked at the same criteria in adults. hmm... That would be a nice study if it hasn't been done.

I'm 19 years old, and I had the I & D done last Monday (6 days ago) and I've been on Bactrim, two pills every twelve hours, since then, and I am healing up quite nicely. Being that the abcess is directly above my knee joint, I still feel some pain and stiffness, but all in all, and especially being seen comparatively to when it was dangerously infectious, it looks pretty good.

Just thought I'd drop my 2 cents in here, you're posts have been very helpful to me.

[ERMudPhud]

I wonder if the real reason/benefit to adding bactrim treatment to a CA-MRSA abcess that has been drained is to clear any colonization in the patient and thus decrease community spread. I don't think that has been looked at and to prove it was working you would have to bring everyone back for post-treatment nasal swabs.

[gbhaebhtqe56453]

Originally Posted by docB

Ann Emerg Med. 2005 Mar;45(3):321-2.

High prevalence of methicillin-resistant Staphylococcus aureus in emergency department skin and soft tissue infections.

Frazee BW, Lynn J, Charlebois ED, Lambert L, Lowery D, Perdreau-Remington F.

Department of Emergency Medicine, Alameda County Medical Center-Highland Campus, Oakland, CA 94602, USA. bradf_98@yahoo.com

STUDY OBJECTIVE: We sought to determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) among emergency department (ED) patients with skin and soft tissue infections, identify demographic and clinical variables associated with MRSA, and characterize MRSA by antimicrobial susceptibility and genotype. METHODS: This was a prospective observational study involving a convenience sample of patients who presented with skin and soft tissue infections to a single urban public hospital ED in California. Nares and infection site cultures were obtained. A health and lifestyle questionnaire was administered, and predictor variables independently associated with MRSA were determined by multivariate logistic regression. All S aureus isolates underwent antibiotic susceptibility testing. Eighty-five MRSA isolates underwent genotyping by pulsed field gel electrophoresis, staphylococcal chromosomal cassette mec (SCC mec ) typing, and testing for Panton-Valentine leukocidin genes. RESULTS: Of 137 subjects, 18% were homeless, 28% injected illicit drugs, 63% presented with a deep or superficial abscess, and 26% required admission for the infection. MRSA was present in 51% of infection site cultures. Of 119 S aureus isolates (from infection site and nares), 89 (75%) were MRSA. Antimicrobial susceptibility among MRSA isolates was trimethoprim/sulfamethoxazole 100%, clindamycin 94%, tetracycline 86%, and levofloxacin 57%. Among predictor variables independently associated with MRSA infection, the strongest was infection type being furuncle (odds ratio 28.6). Seventy-six percent of MRSA cases fit the clinical definition of community associated. Ninety-nine percent of MRSA isolates possessed the SCC mec IV allele (typical of community-associated MRSA), 94.1% possessed Panton-Valentine leukocidin genes, and 87.1% belonged to a single clonal group (ST8:S). CONCLUSION: In this urban ED population, MRSA is a major pathogen in skin and soft tissue infections. Although studies from other practice settings are needed, MRSA should be considered when empiric antibiotic therapy is selected for such infections.

PMID: 15726056 [PubMed - indexed for MEDLINE]

This study has had a pretty big impact on the practice in my group. Most of us are now using Bactrim instead of Keflex for regular, non-IVDA, community acquired abscesses and culturing them. We never cultured these in residency and the rule used to be to not use antibiotics at all. Anyone else changing based on this?

One of my friends is doing the same. He read about it on http://www.drugdelivery.ca/s33916-s-BACTRIM.aspx and he forwarded this address to me. he wanted me check it if it worth using….i read it and I feel that it must be effective.

[Dr.McNinja]

MRSA dose is now 2 tabs BID at our facility.