Three Degrees Help Drive Antibiotic Decision in Cellulitis

Three Degrees Help Drive Antibiotics in Cellulitis

By: M. ALEXANDER OTTO, Family Practice News Digital Network

SAN FRANCISCO – A greater than 3° C difference in skin temperature between affected and unaffected limbs in cellulitis – measured using inexpensive, handheld, infrared laser thermometers – was found to signal the need for hospital admission for intravenous antibiotics.

Skin temperature changes in cellulitis had never been quantified, said Dr. Michael Montalto. "We’ve never had a concept in absolute terms of the differences we feel as clinicians every day. [Our study gives] an idea of the kind of scale that might cause you to think the patient needs to have an admission for IV therapy. At least in our study, if the temperature difference [between the affected and unaffected limb] was above 3 °C, those people were getting IV therapy," he said at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

Of 63 cellulitis patients who were admitted to the hospital for intravenous antibiotic therapy, lesions were on average 3.4 °C warmer (95% confidence interval, 3.0-3.9) than the corresponding location on the unaffected limb. The difference dropped to an average 2.1° C warmer (95% CI, 1.7-2.6) at discharge after a mean stay of 5 days, the investigators found.

Patients in the study, who were 50 years old on average, had mostly lower-limb cellulitis; just over half were men. Nurses took the limb temperatures to keep researchers blinded to the results until the study’s end. Skin temperatures did not correlate with blood pressure, core temperature, or other variables.

Dr. Montalto and his colleagues found that the warmest point on limbs affected by cellulitis dropped from an average of 34.4 °C on the day of admission for intravenous antibiotics to 32° C when patients were well enough to be discharged on oral antibiotics, a statistically significant difference (95% CI, 1.9-3.0).

Furthermore, the results also suggested a role for laser thermometers – which can cost less than $50 at electronic stores and until now have been used mostly for industrial purposes – to measure severity and treatment response in cellulitis, said Dr. Montalto, a hospitalist at Epworth Hospital and Royal Melbourne Hospital. The devices emit two beams that are focused into one dot on the skin, at which point the temperature is read from a screen. The process is quick and painless.

The thermometers are "another tool to use for tricky patients when you are wondering whether or not they are getting better," he said. Current measures – white cell counts, erythema, fever, and skin color, among others – are not specific enough, he said.

The next step in the project is to see if skin temperature helps identify the causative organism in cellulitis, which remains unknown in many cases. Methicillin-resistant Staphylococcus aureus (MRSA) cellulitis, for instance, may project a higher temperature than other types of cellulitis.

"We often have people presenting from nursing homes who don’t have a wound. They just have a big, fat, painful, red leg with nothing to swab. You’ve got no way of determining what the organism is except trial and error. If we could show that the temperature profile helps with that," and, thus, appropriate antibiotic selection, it would be a significant advance, Dr. Montalto said at the meeting, which was sponsored by the American Society for Microbiology.

True to the point, 12 patients (19%) had positive swabs in the study, mostly for staphylococci, but a few MRSA and gram-negative bacteria also showed up.

Dr. Montalto said that he had no relevant financial disclosures.

Family Practice News

A systematic review of bacteremias in cellulitis and erysipelas.

Feb 2012

Gunderson CG, Martinello RA.

Source

Department of Internal Medicine and VA Connecticut Health Care System, Yale School of Medicine, 950 Campbell Avenue, West Haven CT 06516, USA; Veterans Health Administration, Public Health, 950 Campbell Avenue, West Haven CT 06516, USA.

Abstract

OBJECTIVES:

Because of the difficulty of obtaining bacterial cultures from patients with cellulitis and erysipelas, the microbiology of these common infections remains incompletely defined. Given the emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) over the past decade the proportion of infections due to S. aureus has become particularly relevant.

METHODS:

OVID was used to search Medline using the focused subject headings "cellulitis", "erysipelas" and "soft tissue infections". All references that involved adult patients with cellulitis or erysipelas and reported associated bacteremias and specific pathogens were included in the review.

RESULTS:

For erysipelas, 4.6% of 607 patients had positive blood cultures, of which 46% were Streptococcus pyogenes, 29% were other β-hemolytic streptococci, 14% were Staphylococcus aureus, and 11% were Gram-negative organisms. Forcellulitis, 7.9% of 1578 patients had positive blood cultures of which 19% were Streptococcus pyogenes, 38% were other β-hemolytic streptococci, 14% were Staphylococcus aureus, and 28% were Gram-negative organisms.

CONCLUSIONS:

Although the strength of our conclusions are somewhat limited by the heterogeneity of included cases, our results support the traditional view that cellulitis and erysipelas are primarily due to streptococcal species, with a smaller proportion due to S. aureus. Our results also argue against the current distinction between cellulitis and erysipelas in terms of the relative proportion of infections due to S. aureus.

Elsevier-sciVerse

Methicillin-resistant Ascending Facial and Orbital Cellulitis in an Operation Iraqi Freedom Troop Population.

Methicillin-resistant Ascending Facial and Orbital Cellulitis in an Operation Iraqi Freedom Troop Population.
Ophthal Plast Reconstr Surg. 2007 Sep-Oct

Boden JH, Ainbinder DJ.
Department of Ophthalmology, Madigan Army Medical Center, Tacoma, Washington, U.S.A.

PURPOSE: To present a descriptive case series of methicillin-resistant ascending facial and orbital cellulitis in an Operation Iraqi Freedom troop population.

METHODS: A physician's transfer records of patients cared for and or transferred from the 31st and 86th Combat Support Hospitals during Operation Iraqi Freedom between September 2004 and March 2005 were reviewed. Cases of facial and orbital cellulitis caused by a nasal mucosal source were included in the case series.

RESULTS: Five cases of ascending facial and/or orbital cellulitis caused by an aggressive nasal source are reported. All nasal microabscess cultures demonstrated methicillin-resistant Staphylococcus aureus species. None of the patients complained of nasal pain as the chief complaint, and all patients overlooked the follicular abscess at or inside the nares.

CONCLUSIONS: Occult nasal infections with methicillin-resistant Staphylococcus aureus can be the source of an aggressive ascending facial and orbital cellulitis. The nasal source can be overlooked because of the distracting presentation of the orbital and systemic findings. With the increasing prevalence of community-acquired methicillin-resistant Staphylococcus aureus infections, a nasal examination and nasal culture can greatly assist in the diagnosis and management of patients presenting with orbital cellulitis without a clear source of infection.

Lippincott, Williams & Wilkins