Table 1. Comparison of rates of surgical site infections (SSIs) due to methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) between period A (July 2003–June 2006) and period B (July 2006–September 2007), St. John’s Mercy Medical Center, St. Louis, Missouri.
community-associated and health care– associated MRSA strains as causes of SSI is becoming increasingly blurred. Acknowledgments
SSI pathogen, patient group
No. (%) of SSIs Period B
Risk ratio (95% CI)
P
94 (0.31) 13 (0.02)
42 (0.31) 5 (0.02)
0.99 (0.7–1.4) 1.1 (0.4–3.1)
.94 .86
107 (0.13)
47 (0.13)
1.0 (0.7–1.4)
.96
124 (0.41)
53 (0.4)
1.0 (0.7–1.3)
.9
12 (0.02) 136 (0.16)
9 (0.04) 62 (0.17)
1.8 (0.7–4.2) 1.1 (0.8–1.4)
.28 .75
26 (0.09) 7 (0.01)
25 (0.19) 5 (0.02)
2.2 (1.3–3.8) 1.7 (0.5–5.3)
.007 .56
33 (0.04)
30 (0.08)
2.1 (1.3–3.5)
.004
98 (0.32)
28 (0.21)
0.65 (0.4–0.99)
.05
5 (0.01) 103 (0.12)
4 (0.02) 32 (0.09)
1.9 (0.5–7.0) 0.7 (0.5–1.1)
.55 .13
a
Period A
b
Potential conflicts of interest. F.A.M. and S.G.: no conflicts.
MSSA Inpatients Ambulatory patients Overall MRSA Inpatients Ambulatory patients Overall Clindamycin-susceptible MRSA Inpatients Ambulatory patients Overall Clindamycin-resistant MRSA Inpatients
NOTE. x2 test with Yate’s correction was used for all comparisons a b
The n values were as follows: inpatients, 30,450; ambulatory patients, 54,940; overall, 85,390. The n values were as follows: inpatients, 13,417; ambulatory patients, 23,233; overall, 36,650.
(table 1). Similarly, a decrease in the rate of clindamycin-resistant MRSA was observed among inpatients (risk ratio, 0.65; 95% CI, 0.4–0.99) but was not observed among ambulatory patients. There were no significant changes in the rates of methicillin-susceptible S. aureus SSIs among inpatients or ambulatory patients. Among inpatients, the proportion of MRSA SSIs caused by clindamycin-susceptible MRSA increased significantly, from 21% during period A to 47% during period B (26 of 124 SSIs vs. 25 of 53 SSIs; OR, 3.4 [95% CI, 1.7–6.7]; P ! .001, by Fisher’s exact test). However, among ambulatory patients, the proportion of MRSA SSIs caused by clindamycin-susceptible MRSA did not change significantly, accounting for 7 (58%) of 12 cases during period A and 5 (56%) of 9 cases during period B (OR, 0.9 [95% CI, 0.2– 5.1]; P p 1.0, by Fisher’s exact test). Our finding of a significant increase in clindamycin-susceptible MRSA SSI rates among inpatients with a concomitant de-
crease in the rate of clindamycin-resistant MRSA nearly mirrors the findings of Popovich et al. [1], who reported an increase in the rate of community-associated MRSA strains among individuals with nosocomial bloodstream infections, with a concomitant decrease in the rate of health care–associated MRSA strains [1]. Furthermore, lack of a concurrent increase in rates of clindamycin-susceptible MRSA SSI among ambulatory surgical patients, combined with stable methicillin-susceptible S. aureus SSI rates suggest that the increase in clindamycin-susceptible MRSA SSIs among inpatients was more reflective of its nosocomial transmission than of its increased prevalence in the general population. Whether the partial replacement of clindamycin-resistant MRSA by clindamycin-susceptible MRSA among inpatient surgical patients is a reflection of the potential for enhanced virulence and/or spread of the latter strain [5] in health care settings deserves further study. In the meantime, it appears that the line between
Department of Infection Control, St. John’s Mercy Medical Center, St. Louis, Missouri References 1. Popovich KJ, Weinstein RA, Hota B. Are community-associated methicillin-resistant Staphylococcus aureus (MRSA) strains replacing traditional nosocomial MRSA strains? Clin Infect Dis 2008; 46:787–94. 2. Manian FA, Meyer L. Comprehensive surveillance of surgical wound infections in outpatient and inpatient surgery. Infect Control Hosp Epidemiol 1990; 11:515–20. 3. Garver JS, Jarvis WR, Emori TG, Horan TC, Hughes JM. CDC definitions for nosocomial infections, 1988. Am J Infect Control 1988; 16: 128–40. 4. Popovich K, Hota B, Rice T, Aroutcheva A, Weinstein RA. Phenotypic prediction rule for community-associated methicillin-resistant Staphylococcus aureus. J Clin Microbiol 2007; 45:2293–5. 5. Miller LG, Binh AD. Colonization, fomites, virulence: rethinking the pathogenesis of community-associated methicillin-resistant Staphylococcus aureus infections. Clin Infect Dis 2008; 46:752–60. Reprints or correspondence: Dr. Farrin A. Manian, 621 S. New Ballas, 7018 B, St. Louis, MO 63141 (
[email protected]). Clinical Infectious Diseases 2008; 47:434–5 2008 by the Infectious Diseases Society of America. All rights reserved. 1058-4838/2008/4703-0028$15.00 DOI: 10.1086/589930
Mixed Cryoglobulinemia due to Brucellosis To the Editor—Brucellosis is an anthropozoonosis of worldwide distribution. It is known that Brucella infection results in systemic damage and diverse clinical manifestations—mainly joint involvement, as a consequence of immunological abnormalities manifested by inmunocomplex production [1]. Various manifestations (e.g., glomerulonephritis, hepatitis, arthritis, and cutaneous vasculitis) result from deposits of inmuno-
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Ambulatory patients Overall
Farrin A. Manian and Sandy Griesnauer
were caused by B. melitensis [6, 7]. The mean duration of illness was 4.5 months [7, 9], although the vasculitis occurred up to the end of this period. Cases of mixed cryoglobulinemia due to brucellosis have a good response to treatment with tetracyclines and corticosteroids. In the most recently reported case [7], purpuric lesions due to prednisoneassociated brucellosis resolved after receipt of therapy (100 mg of doxycycline twice per day for 6 weeks); this resolution coincided with a decrease in the serum cryoglobulin level (to 420 mg/mL; normal value, !600 mg/mL). Although they represent a small proportion of the total number of Brucellainfected patients, the described patients with mixed cryoglobulinemia syndrome secondary to brucellosis are worth mentioning. In summary, for patients with purpura and cryoglobulinemia in the context of a subacute or chronic febrile illness, clinicians should consider the possibility of brucellosis, especially if patients have emigrated from an area of endemicity or have risk factors for brucellosis. Acknowledgments Potential conflicts of interest. All authors: no conflicts. Sandra Delgado,1 Francisco Bravo,2 and Eduardo Gotuzzo1 1
Institute of Tropical Medicine “Alexander von Humbolt” and 2Infectious Diseases, Tropical Medicine, and Dermatology Department, Cayetano Heredia Hospital, Lima, Peru References 1. Dammacco F, Sansonmo D, Piccolli C, et al. The cryoglobulins: an overview. Eur J Clin Invest 2001; 31:628–38. 2. Hermida Lazcano I, Sa´ez Me´ndez L, Solera Santos J. Mixed cryoglobulinemia with renal failure, cutaneous vasculitis and peritonitis due to Brucella melitensis. J Infect 2005; 51:e257–9. 3. Yrribaren J, Lo´pez L. Cryoglobulinemia and cutaneous vasculitis in human brucellosis. J Clin Immunol 1987; 7:471–4. 4. Ferri C, Mascia MT. Cryoglobulinemic vasculitis. Curr Opin Rheumatol 2006; 18:54–63. 5. Gotuzzo E, Alarco´n G, Bocanegra T, et al. Articular involvement in human brucellosis: a retrospective analysis of 304 cases. Semin Arthritis Rheum 1982; 12:245–55. 6. Gotuzzo E, Carrillo C. Brucella. In: Gorbach S,
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Barded J, Blacklow N, eds. Infectious disease. 2nd ed. Philadelphia: WB Saunders Company, 1998:1837–45. 7. Ticse R, Varela L, Berrocal A, et al. Mixed cryoglobulinemia syndrome due to brucellosis. Rev Med Hered 2007; 18:34–5. 8. Ferri C, Zignego A, Pileri SA. Crioglobulins. J Clin Pathol 2002; 55:4–13. 9. Hermida I, Garcı´a F, Ramos C, et al. Vasculitis necrosante como manifestacio´n cuta´nea de brucelosis. Enferm Infecc Microbiol Clin 1994; 12:515–6. Reprints or correspondence: Dr. Eduardo Gotuzzo, Institute of Tropical Medicine “Alexander von Humbolt,” Cayetano Heredia Hospital, Av. Honorio Delgado 430 Urb. Ingenierı´a–San Martı´n de Porras, Lima, Peru´ (
[email protected]). Clinical Infectious Diseases 2008; 47:435–6 2008 by the Infectious Diseases Society of America. All rights reserved. 1058-4838/2008/4703-0029$15.00 DOI: 10.1086/589932
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complex [2]. Among the diverse cutaneous lesions seen in patients with brucellosis, one of the rarest is the association between cutaneous vasculitis and serum cryoblobulinemia, which was reported elsewhere [3]. Mixed cryoglobulinemia is a syndrome that comprises purpura, artrhalgias, and weakness; it is caused by specific types of immunoglobulins called “cryoglobulins.” Both type II and type III cryoglobulins are associated with lymphoproliferative, autoimmune, or infectious disorders [1 , 4]. Only 5 cases of vasculitis with cryoglobulinemia secondary to Brucella infection have been reported worldwide (4 cases were reported from Peru, and 1 case was reported from Spain [5, 6]). The last case to have been reported occurred in a Peruvian woman, for whom purpura on the lower extremities and fever were the prominent features. The results of serum agglutination and Rose Bengal testing for brucellosis were positive. The cryoglobulins test result was positive, with a reported cryoglobulin level of 900 mg/mL (polyclonal IgG-IgA-IgM). Skin biopsy revealed leukocytoclastic vasculitis [7]. The ages of the 5 patients with mixed cryoglobulinemia syndrome secondary to brucellosis ranged from 17 to 71 years, and there was preponderance of women over men (ratio, 4:1). Purpura and fever were the most common clinical manifestations in these patients. However, in most cases, fever is not a classic sign of mixed cryoglobulinemia [8]. In addition, hepatomegaly was present in 100% of patients, whereas splenomegaly and abdominal pain were not documented in all patients. The isolated cryoglobulins were characterized as mixed polyclonal or type III in the 5 patients. The results of serologic tests for hepatitis C virus and hepatitis B virus were negative for all patients. In 4 of the cases, Brucella melitensis was isolated from bone marrow cultures; in the remaining reported case, the bone marrow culture yielded negative results. However, it is worth mentioning that almost 100% of the cases reported in Peru
