A
CLONE OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS AMONG PROFESSIONAL
FOOTBALL PLAYERS.
Kazakova SV, et al. N Engl J Med. 2005 Feb 3;352(5):468-75.
BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging cause of infections outside of health care settings. We investigated an outbreak of abscesses due to MRSA among members of a professional football team and examined the transmission and microbiologic characteristics of the outbreak strain.
METHODS: We conducted a retrospective cohort study and nasal-swab survey of 84 St. Louis Rams football players and staff members. S. aureus recovered from wound, nasal, and environmental cultures was analyzed by means of pulsed-field gel electrophoresis (PFGE) and typing for resistance and toxin genes. MRSA from the team was compared with other community isolates and hospital isolates.
RESULTS: During the 2003 football season, eight MRSA infections occurred among 5 of the 58 Rams players (9 percent); all of the infections developed at turf-abrasion sites. MRSA infection was significantly associated with the lineman or linebacker position and a higher body-mass index. No MRSA was found in nasal or environmental samples; however, methicillin-susceptible S. aureus was recovered from whirlpools and taping gel and from 35 of the 84 nasal swabs from players and staff members (42 percent). MRSA from a competing football team and from other community clusters and sporadic cases had PFGE patterns that were indistinguishable from those of the Rams' MRSA; all carried the gene for Panton-Valentine leukocidin and the gene complex for staphylococcal-cassette-chromosome mec type IVa resistance (clone USA300-0114).
CONCLUSIONS: We describe a highly conserved,
community-associated MRSA clone that caused abscesses among professional
football players and that was indistinguishable from isolates from various
other regions of the
AN
EPIDEMIC OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS SOFT TISSUE INFECTIONS
AMONG MEDICALLY UNDERSERVED PATIENTS.
Young DM, et al. Arch Surg. 2004 Sep;139(9):947-51.
HYPOTHESIS: A high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in soft tissue infections presents a treatment challenge. DESIGN: Retrospective analysis.
SETTING: The
PATIENTS: Patients treated at the ISIS Clinic from
MAIN OUTCOME MEASURES: Information on patient demographics, surgical procedures, microbiologic studies, and antibiotic treatments was obtained for all patients treated in the ISIS Clinic. Microbial data and antibiotic susceptibility pattern of S aureus, treatment outcome, and antibiotic prescribed were analyzed for all evaluable patients.
RESULTS: The ISIS Clinic treated 6156 unique patients for 12,012 episodes of infection. In this cohort, 5164 (84%) were either homeless or had no health insurance. More than half of the patients (58%) were injection drug users, but most had only 1 prior visit to the clinic (62%). Patients underwent a surgical procedure 7707 times (64%). Of the 837 positive cultures obtained, S aureus was recovered 695 times (83%), and 525 (63%) of the cultures contained MRSA. Therefore, a full 76% of all S aureus isolated was MRSA. In a subset analysis of 622 cultures collected prospectively from consecutive patients, 282 (45%) grew organisms, of which 256 (91%) were S aureus. MRSA represented 59% of all S aureus isolated. Homelessness and injection drug use were risk factors for infection by S aureus and MRSA. In another subgroup of patients with soft tissue infections that required admission to the hospital, MRSA was recovered from the cultures in 149 patients. In these patients with MRSA, 44 (30%) only received a beta-lactam antibiotic, inactive against MRSA, and had full resolution of their infection.
CONCLUSIONS: The prevalence of MRSA soft tissue infections in the medically underserved ISIS Clinic cohort is extremely high. The transmission of the MRSA seems to be in the community. Antibiotic therapy directed at MRSA may not be needed in a large number of patients with these soft tissue infections. Studies to identify the source and cause of this MRSA outbreak are urgently needed. Clinical trials to examine the need for antibiotic therapy in soft tissue infections should be conducted.
COMMUNITY-ACQUIRED
METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS IN CHILDREN WITH NO IDENTIFIED
PREDISPOSING RISK.
CONTEXT: Community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections in children have occurred primarily in individuals with recognized predisposing risks. Community-acquired MRSA infections in the absence of identified risk factors have been reported infrequently.
OBJECTIVES: To determine whether community-acquired MRSA infections in children with no identified predisposing risks are increasing and to define the spectrum of disease associated with MRSA isolation.
DESIGN: Retrospective review of medical records.
PATIENTS: Hospitalized children with S aureus isolated between August 1988 and July 1990 (1988-1990) and between August 1993 and July 1995 (1993-1995).
SETTING: The
MAIN OUTCOME MEASURES: Prevalence of community-acquired MRSA over time, infecting vs colonizing isolates, and risk factors for disease.
RESULTS: The number of children hospitalized with community-acquired MRSA disease increased from 8 in 1988-1990 to 35 in 1993-1995. Moreover, the prevalence of community-acquired MRSA without identified risk increased from 10 per 100000 admissions in 1988-1990 to 259 per 100000 admissions in 1993-1995 (P<.001), and a greater proportion of isolates produced clinical infection. The clinical syndromes associated with MRSA in children without identified risk were similar to those associated with community-acquired methicillin-susceptible S aureus. Notably, 7 (70%) of 10 community-acquired MRSA isolates obtained from children with an identified risk were nonsusceptible to at least 2 drugs, compared with only 6 (24%) of 25 isolates obtained from children without an identified risk (P=.02).
CONCLUSIONS: These findings demonstrate that the prevalence of community-acquired MRSA among children without identified risk factors is increasing.
MANAGEMENT AND
OUTCOME OF CHILDREN WITH SKIN AND SOFT TISSUE ABSCESSES CAUSED BY
COMMUNITY-ACQUIRED METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS.
Lee MC, et al. Pediatr Infect Dis J. 2004 Feb;23(2):123-7.
BACKGROUND: Although the epidemiology of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has been explored in many investigations, management of this emerging infection has not been well-studied. For non-methicillin-resistant Staphylococcus aureus skin and soft tissue abscesses, incision and drainage is generally adequate therapy without the use of antibiotics, but this has not been established for CA-MRSA.
METHODS: Children presenting to Children's Medical Center of Dallas for management of skin and soft tissue abscesses caused by culture-proved CA-MRSA were prospectively followed. We analyzed data from the initial evaluation and from two follow-up visits that focused on the management and outcome of CA-MRSA infection. Retrospective chart review was performed 2 to 6 months after the initial visit.
RESULTS: Sixty-nine children were identified with culture-proved CA-MRSA skin and soft tissue abscess. Treatment consisted of drainage in 96% of patients and wound packing in 65%. All children were treated with antibiotics. Five patients (7%) were prescribed an antibiotic to which their CA-MRSA isolate was susceptible before culture results were known. Four patients (6%) required hospital admission on the first follow-up; none of these patients had received an antibiotic effective against CA-MRSA. A significant predictor of hospitalization was having a lesion initially >5 cm (P = 0.004). Initial ineffective antibiotic therapy was not a significant predictor of hospitalization (P = 1.0). Of the 58 patients initially given an ineffective antibiotic and managed as outpatients, an antibiotic active against CA-MRSA was given to 21 (36%) patients after results of cultures were known. No significant differences in response were observed in those who never received an effective antibiotic than in those who did.
CONCLUSIONS: Incision and drainage without adjunctive antibiotic therapy was effective management of CA-MRSA skin and soft tissue abscesses with a diameter of <5 cm in immunocompetent children.
EMERGENCE
OF COMMUNITY-ASSOCIATED METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS AT A
Buckingham SC, et al. Pediatr Infect Dis J. 2004 Jul;23(7):619-24.
BACKGROUND: An epidemiologic investigation was performed
because of a perceived increase in infections caused by community-associated methicillin-resistant Staphylococcus aureus
(MRSA) among children in the greater
METHODS: We reviewed medical records of 289 children evaluated from January 2000 to June 2002 at a children's hospital. Clinical criteria were applied to classify MRSA isolates as community-associated (n=51) or health care-associated (n=138). The relatedness of 33 archived S. aureus isolates was evaluated using pulsed field gel electrophoresis (PFGE) of Sma I-digested genomic DNA; a common pulsed field type was defined as > or = 80 % similarity based on Dice coefficients. PFGE profiles were compared with those in a national database of MRSA isolates.
RESULTS: During the first 18 study months, 46 of 122 MRSA isolates (38%) were community-associated; this proportion increased to 106 of 167 isolates (63%) during the last 12 study months (P <.0001). Community-associated isolates were recovered from normally sterile sites as frequently as were health care-associated isolates (16% versus 13%). PFGE revealed that 15 of 16 community-associated isolates shared a common pulsed field type (USA300) observed in community-associated MRSA infections elsewhere in the United States and characterized by staphylococcal cassette chromosome mec type IV, clindamycin susceptibility and erythromycin resistance mediated by an msr A-encoded macrolide efflux pump.
CONCLUSIONS: Community-associated MRSA has emerged as a
potentially invasive pathogen among children in the greater
COMMUNITY-ACQUIRED
METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS SKIN INFECTION: A RETROSPECTIVE
ANALYSIS OF CLINICAL PRESENTATION AND TREATMENT OF A LOCAL OUTBREAK.
Iyer S, Jones DH. J Am Acad Dermatol. 2004 Jun;50(6):854-8.
BACKGROUND: Methicillin-resistant
Staphylococcus aureus (MRSA), a well-known nosocomial pathogen, is now emerging as a prominent cause
of community acquired infections. We have noted an increase in number of cutaneous infections in
METHODS: A retrospective chart review of 39 patients with 46 involved sites was performed. The sites of infection, morphology, antimicrobial susceptibility, and definitive treatment were evaluated.
RESULTS: Cutaneous abscesses were the most common presentation of cutaneous MRSA infection. Definitive treatment consisted of incision and drainage in combination with antimicrobial therapy. The most effective antibiotics were vancomycin, trimethoprim/sulfamethoxazole in combination with rifampin, and linezolid.
CONCLUSION: Community acquired MRSA infection appears to be a growing problem requiring prompt diagnosis and treatment. First line treatment is incision and drainage in combination with linezolid, vancomycin, or combination trimethoprim/sulfamethoxazole and rifampin.
SPIDER BITES
PRESENTING WITH METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS SOFT TISSUE
INFECTION REQUIRE EARLY AGGRESSIVE TREATMENT.
Fagan SP, et al. Surg Infect (Larchmt). 2003 Winter;4(4):311-5.
BACKGROUND: Occasionally, spider bites result in necrotizing soft tissue infections that require aggressive surgical debridement and treatment with intravenous antibiotics. With the rise of microbial resistance in the community, management with standard gram-positive intravenous antibiotic coverage may be ineffective. Our objective was to determine the infectious organisms cultured following wide local excision of soft tissue infections caused by spider bites. We hypothesized that the majority of isolated organisms would be sensitive to penicillin based antibiotics.
METHODS: From March 2000 to November 2001, the medical records were reviewed of patients who presented to a tertiary care hospital with serious soft tissue infections secondary to spider bites that required surgical treatment. For each patient, demographics, symptoms, size, time to surgical evaluation (TTSE), temperature, white blood cell (WBC) count, surgical procedure, and culture data were collected. Data are presented as mean +/- SEM.
RESULTS: Thirty-eight patients presented with serious soft tissue infections secondary to spider bites that required surgical debridement and treatment with intravenous antibiotics. Twenty-nine percent (11 of 38) of these patients had failed initial outpatient therapy with penicillin-based oral antibiotics. The mean TTSE was 5.0 +/- 0.5 days (range = 2-14 days; median = 4.5 days). The most common presenting symptoms were pain and erythema surrounding the bite site. The mean temperature was 98.8 +/- 0.6 degrees F (range = 97.2-102.2 degrees F; median = 99.2 degrees F). The mean WBC count was 12.6 +/- 0.8 mm3. All patients required wide surgical debridement of the infected area. The mean size of the excised tissue was 26 +/- 4 cm2 (range = 4-120 cm2; median = 16 cm2). Every patient had cultures that grew Staphylococcus aureus. In 86.8% of patients, S. aureus was found to be methicillin-resistant (MRSA). All isolated organisms were sensitive to trimethoprim-sulfamethoxazole.
CONCLUSIONS: In our experience, patients who presented with soft tissue infections as result of spider bites predominantly had methicillin-resistant S. aureus infections, corresponding to the increased incidence of MRSA reported in the community. Therefore, a more aggressive approach to the management of spider bites presenting with severe cellulitis is warranted. Routine treatment should include aggressive surgical debridement, intraoperative wound cultures, the empiric use of antibiotics with activity against MRSA, and adjustment of antimicrobial therapy based on culture and sensitivity data.
COMMENTS:
Community MRSA seems to be distinct from nosocomial
MRSA as it is sensitive to several