Prevalence of Nasal Colonization Among Patients With Community‐Associated Methicillin‐Resistant Staphylococcus aureus Infection and Their Household Contacts •

Department of Internal Medicine, St. John Hospital and Medical Center, Detroit, MI, USA.
Infection Control and Hospital Epidemiology (Impact Factor: 4.18). 09/2007; 28(8):966-9. DOI: 10.1086/518965
Source: PubMed


To evaluate the prevalence of colonization among patients with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection and their household contacts.
Prospective, observational laboratory study of nasal colonization among patients and their household members from September 15, 2004, to February 20, 2006.
A 600-bed, urban, academic medical center.
Fifty-one patients who presented with CA-MRSA infections and 49 household members had cultures of nasal swab specimens performed.
Skin and soft-tissue infections were seen in 50 patients (98%) and 2 household members. Twenty-one (41%) of 51 patients and 10 (20%) of 49 household members were colonized with MRSA. An additional 5 patients (10%) and 12 household members (24%) were colonized with methicillin-susceptible Staphylococcus aureus. Most MRSA isolates (95%; infective and colonizing) carried the staphylococcal cassette chromosome mec type IV complex, and 67% represented a single clone, identical to USA 300. Of the colonized household members, 5 had isolates related to the patients' infective isolate.
The frequency of CA-MRSA colonization among household members of patients with CA-MRSA infections is higher than rates reported among the general population. Among colonized household members, only half of the MRSA strains were related to the patients' infective isolate. Within the same household, multiple strains of CA-MRSA may be present.

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Available from: Kathleen Riederer, Feb 27, 2014
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    • "Numerous studies have documented the role of the household as a community reservoir for Staphylococcus aureus [1]–[4]. After a household member becomes infected, high levels of S. aureus colonization and infection often occur among other household members [5]–[8]. These reports have observed that epidemic clones tend to “ping pong” among family members, resulting in a high rate of recurrent infections [9]–[11]. "
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    ABSTRACT: Background The household is a recognized community reservoir for Staphylococcus aureus. This study investigated potential risk factors for intra-household S. aureus transmission, including the contribution of environmental contamination. Methods We investigated intra-household S. aureus transmission using a sample of multiple member households from a community-based case-control study examining risk factors for CA-MRSA infection conducted in Northern Manhattan. During a home visit, index subjects completed a questionnaire. All consenting household members were swabbed, as were standardized environmental household items. Swabs were cultured for S. aureus. Positive isolates underwent further molecular characterization. Intra-household transmission was defined as having identical strains among two or more household members. Multiple logistic regression was used to identify independent risk factors for transmission. Results We enrolled 291 households: 146 index cases, 145 index controls and 687 of their household contacts. The majority of indexes were Hispanic (85%), low income (74%), and female (67%), with a mean age of 31 (range 1–79). The average size of case and control households was 4 people. S. aureus colonized individuals in 62% of households and contaminated the environment in 54% of households. USA300 was the predominant clinical infection, colonizing and environmental strain. Eighty-one households had evidence of intra-household transmission: 55 (38%) case and 26 (18%) control households (P<.01). Environmental contamination with a colonizing or clinical infection strain (aOR: 5.4 [2.9–10.3] P<.01) and the presence of a child under 5 (aOR: 2.3 [1.2–4.5] P = .02) were independently associated with transmission. In separate multivariable models, environmental contamination was associated with transmission among case (aOR 3.3, p<.01) and control households (aOR 27.2, p<.01). Conclusions Environmental contamination with a colonizing or clinical infection strain was significantly and independently associated with transmission in a large community-based sample. Environmental contamination should be considered when treating S. aureus infections, particularly among households with multiple infected members.
    Full-text · Article · Nov 2012 · PLoS ONE
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    • "Despite limited data on intrafamilial transmission and nasal colonization of family members of patients with CA-MRSA infections [17-21], some experts recommend identifying possible household carriers of S. aureus in order to decolonize them by using mupirocin nasal ointment [22]. Whether routine decolonization of all family contacts of patients with recurrent CA-MRSA skin infections is needed remains unclear. "
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    ABSTRACT: To measure Methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization prevalence in household contacts of children with current community associated (CA)-MRSA infections (study group) in comparison with a group of household contacts of children without suspected Staphylococcus aureus infection (a control group). This is a cross sectional study. Cultures of the anterior nares were taken. Relatedness of isolated strains was tested using pulse field gel electrophoresis (PFGE). The prevalence of MRSA colonization in the study group was significantly higher than in the control group (18/77 (23%) vs 3/77 (3.9%); p ≤ 0.001). The prevalence of SA colonization was 28/77 (36%) in the study group and 16/77 (21%) in the control group (p = 0.032). The prevalence of SA nasal colonization among patients was 6/24 (25%); one with methicillin-susceptible S. aureus (MSSA) and 5 with MRSA. In the study (patient) group, 14/24 (58%) families had at least one household member who was colonized with MRSA compared to 2/29 (6.9%) in the control group (p = 0.001). Of 69 total isolates tested by PFGE, 40 (58%) were related to USA300. Panton-Valetine leukocidin (PVL) genes were detected in 30/52 (58%) tested isolates. Among the families with ≥1 contact colonized with MRSA, similar PFGE profiles were found between the index patient and a contact in 10/14 families. Prevalence of asymptomatic nasal carriage of MRSA is higher among household contacts of patients with CA-MRSA disease than control group. Decolonizing such carriers may help prevent recurrent CA-MRSA infections.
    Full-text · Article · Feb 2012 · BMC Infectious Diseases
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    • "Screening and decolonization therapy are important components in the prevention and control of HA-MRSA (Kluytmans et al., 1997; Davis et al., 2004; Cosgrove et al., 2003). Studies have shown that the identification of CA- MRSA colonization may require screening of sites other than the nares but the efficacy of CA-MRSA decolonization is unclear (Popovich & Hota, 2008; Zafar et al., 2007). Guidelines for the management of PVL-associated S. aureus in England recommend topical decolonization without prior screening of the primary case (HPA, 2008). "
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    ABSTRACT: Outbreaks or clusters of community-acquired meticillin-resistant Staphylococcus aureus (CA-MRSA) within families have been reported. We describe a family cluster of CA-MRSA skin and soft-tissue infection where CA-MRSA was suspected because of recurrent infections which failed to respond to flucloxacillin. While the prevalence of CA-MRSA is low worldwide, CA-MRSA should be considered in certain circumstances depending on clinical presentation and risk assessment. Surveillance cultures of family contacts of patients with MRSA should be considered to help establish the prevalence of CA-MRSA and to inform the optimal choice of empiric antibiotic treatment.
    Preview · Article · Apr 2010 · Journal of Medical Microbiology
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