Prospective Multicenter Study of Community-Associated Skin and Skin Structure Infections due to Methicillin-Resistant Staphylococcus aureus in Buenos Aires, Argentina

Background. Community-associated methicillin-resistant Staphylococcus aureus(CAMRSA) is now the most common cause of skin and skin structure infections (SSSI) in several world regions. In Argentina prospective, multicenter clinical studies have only been conducted in pediatric populations. Objective. Primary: describe the prevalence, clinical and demographic characteristics of adult patients with community acquired SSSI due to MRSA; secondary: molecular evaluation of CA-MRSA strains. Patients with MRSA were compared to those without MRSA. Material and Methods. Prospective, observational, multicenter, epidemiologic study, with molecular analysis, conducted at 19 sites in Argentina (18 in Buenos Aires)between March 2010 and October 2011. Patients were included if they were ≥ 14 years, were diagnosed with SSSI, a culture was obtained, and there had no significant healthcare contact identified. A logistic regression model was used to identify factors associated with CA-MRSA. Pulse field types, SCCmec, and PVL status were also determined. Results. A total of 311 patients were included. CA-MRSA was isolated in 70% (218/311) of patients. Clinical variables independently associated with CA-MRSA were: presence of purulent lesion (OR 3.29; 95%CI 1.67, 6.49) and age <50 years (OR 2.39; 95%CI 1.22, 4.70). The vast majority of CA-MRSA strains causing SSSI carried PVL genes (95%) and were SCCmec type IV. The sequence type CA-MRSA ST30 spa t019 was the predominant clone. Conclusions. CA-MRSA is now the most common cause of SSSI in our adult patients without healthcare contact. ST30, SCCmec IV, PVL+, spa t019 is the predominant clone in Buenos Aires, Argentina.Fil: Lopez Furst, Maria Jose. Sanatorio Municipal Dr. Julio Méndez, Ciudad Autónoma de Buenos Aires; Argentina;Fil: de Vedia, Lautaro. Gobierno de la Ciudad de Buenos Aires. Htal.de Infecciosas F.j. Muñiz; Argentina;Fil: Fernandez, Silvina. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Quimica Biologica. Cat.de Microbiologia; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina;Fil: Gardella, Noella Mariel. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Quimica Biologica. Cat.de Microbiologia; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina;Fil: Ganaha, Cristina. Pcia. de Buenos Aires. Hospital Vicente López y Planes, Gral. Rodríguez; Argentina;Fil: Prieto, Sergio. Provincia de Buenos Aires. Hospital Nuestra Señora de Luján; Argentina;Fil: Carbone, Edith. Hospital Aeronautico Central; Argentina;Fil: Lista, Nicolás. Gobierno de la Ciudad de Buenos Aires. Htal.de Infecciosas F.j. Muñiz; Argentina;Fil: Rotryng, Flavio. Universidad Abierta Interamericana; Argentina;Fil: Morera, Graciana I.. Hospital Dr. Jose Cullen; Argentina;Fil: Mollerach, Marta Eugenia. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Quimica Biologica. Cat.de Microbiologia; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina;Fil: Stryjewski, Martin E.. Centro de Educaciones Medicas E Investig.Clinica "Norberto Quirno"; Argentina

Most common antibiotic treatments, changes in therapy and drainage in patients with skin and skin structure infections.

<p>MRSA denotes methicillin-resistant <i>Staphylococcus aureus</i>.</p>*<p>Comparing patients infected with community-associated MRSA vs. those patients without community-associated MRSA.</p>†<p>It refers to drainage without incision (e.g. needle drainage).</p

Logistic regression model identifying clinical variables associated with community-associated MRSA in patients with skin and skin structure infections.

<p>MRSA denotes methicillin-resistant <i>Staphylococcus aureus</i>; OR, odds ratio; 95%CI, confidence intervals 95%.</p

Microbiological results and MRSA susceptibilities in patients with skin and skin structure infections.

<p>MRSA denotes methicillin-resistant <i>Staphylococcus aureus</i>; MSSA, methicillin-susceptible <i>Staphylococcus aureus</i>; TMP-SMX, trimethoprim-sulphametoxazole.</p>*<p>From the total of patients with positive cultures; 275 pathogens were isolated from 271 patients; 4 patients had two pathogens isolated, respectively; other pathogens include <i>Proteus mirabilis</i> (n = 2), <i>Citrobacter spp</i> (n = 2), <i>Acinetobacter spp</i> (n = 1), E.coli (n = 1), <i>E. faecalis</i> (n = 1).</p>†<p>A single patient may have more than one type of culture.</p>‡<p>From the total of isolates tested; susceptibilities were determined at each microbiology laboratory following their standards.</p

Molecular characteristics of community-associated MRSA in patients with skin and skin structure infections: pulse fieldtypes, sequence types, <i>mec</i> and <i>spa</i> types.

<p>Numbers within parenthesis indicate the number of isolates belonging to each <i>spa</i> type or SCC<i>mec</i> type.</p><p>ST denotes sequence type; ND, not determined; NT, non-typeable.</p>*<p>A representative proportion of isolates from each pulse field type were studied.</p

Pulse field patterns of representative community MRSA isolates in patients with skin and skin structure infections.

<p>Lane 1 and 14, pulse field type A clone (CAA); lane 2, control pulse field type C; lane 5, pulse field type A; lanes 13 and 7 other pulse field types; lanes 3, 4, 6 and 8–12 pulse field type C.</p

Clinical and demographic characteristics in patients with skin and skin structure infections due to community-associated MRSA.

<p>MRSA denotes methicillin-resistant <i>Staphylococcus aureus</i>; CA-MRSA denotes community-associated MRSA; BMI, body mass index.</p><p>Data are displayed with n/N (%), except for continuous variables which are expressed by mean or median (standard deviation or interquartile range).</p><p>Predisposing factors for skin infections as well predisposing factors for Community MRSA displayed in this table were selected from medical literature. Comparisons were exploratory.</p>*<p>Comparing patients with community-associated MRSA vs. those without community-associated MRSA.</p>†<p>Including furunculosis as a predisposing factor.</p>‡<p>From the total of patients with nasal swabs.</p

Prospective multicenter study of community-associated skin and skin structure infections due to methicillin-resistant Staphylococcus aureus in Buenos Aires, Argentina.

BACKGROUND: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is now the most common cause of skin and skin structure infections (SSSI) in several world regions. In Argentina prospective, multicenter clinical studies have only been conducted in pediatric populations. OBJECTIVE: PRIMARY: describe the prevalence, clinical and demographic characteristics of adult patients with community acquired SSSI due to MRSA; secondary: molecular evaluation of CA-MRSA strains. Patients with MRSA were compared to those without MRSA. MATERIALS AND METHODS: Prospective, observational, multicenter, epidemiologic study, with molecular analysis, conducted at 19 sites in Argentina (18 in Buenos Aires) between March 2010 and October 2011. Patients were included if they were ≥ 14 years, were diagnosed with SSSI, a culture was obtained, and there had no significant healthcare contact identified. A logistic regression model was used to identify factors associated with CA-MRSA. Pulse field types, SCCmec, and PVL status were also determined. RESULTS: A total of 311 patients were included. CA-MRSA was isolated in 70% (218/311) of patients. Clinical variables independently associated with CA-MRSA were: presence of purulent lesion (OR 3.29; 95%CI 1.67, 6.49) and age <50 years (OR 2.39; 95%CI 1.22, 4.70). The vast majority of CA-MRSA strains causing SSSI carried PVL genes (95%) and were SCCmec type IV. The sequence type CA-MRSA ST30 spa t019 was the predominant clone. CONCLUSIONS: CA-MRSA is now the most common cause of SSSI in our adult patients without healthcare contact. ST30, SCCmec IV, PVL+, spa t019 is the predominant clone in Buenos Aires, Argentina