Staphylococcus, not MRSA? A Final Report of Carriage and Conversion Rates in Nursing Students

Rodney E. Rohde; Tom Patterson; Barbara Covington; Bob Edward Vásquez; Gerald Redwine; Emillio Carranco

doi:10.29074/ascls.27.1.21

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Rodney E. Rohde, PhD, MS, SV, SM(ASCP)^CMMB^CM⇑
1. Texas State University, College of Health Professions, Clinical Laboratory Science, San Marcos, TX
Tom Patterson, MS, BS, MT(ASCP)
1. Texas State University, College of Health Professions, Clinical Laboratory Science, San Marcos, TX
Barbara Covington, PhD, RN
1. Texas State University, College of Health Professions, St. David's School of Nursing, San Marcos, TX
Bob Edward Vásquez, PhD
1. Texas State University, College of Applied Arts, School of Criminal Justice, San Marcos, TX
Gerald Redwine, MS, CLS (ASCP)
1. Texas State University, College of Health Professions, Clinical Laboratory Science, San Marcos, TX
Emillio Carranco, MD
1. Texas State University, Student Health Center, San Marcos, TX

Address for Correspondence: Rodney E. Rohde, PhD, MS, SV, SM(ASCP)^CMMB^CM, Chair & Professor, CLS, Associate Dean of Research, College of Health Professions, Texas State University, Clinical Laboratory Science, HPB 363, 601 University Drive, San Marcos, TX 78666-4616, 512-245-2562, rrohde{at}txstate.edu

Abstract

OBJECTIVE: To evaluate and characterize staphylococcal carriage, possibly including methicillin-resistant Staphylococcus aureus (MRSA), and conversion rates in nursing students across clinical semester rotations and to describe risk factors.

DESIGN: A prospective longitudinal cohort design with six times of measurement. Data collected August 2010 to May 2012. Institutional Review Board approval (2010F5693)

SETTING: Texas State University, San Marcos, TX

PARTICIPANTS: Eighty-seven nursing students.

INTERVENTIONS: A positive MRSA swab was considered an end point for participation. Intervention offered was bactroban (mupirocin) for nasal decolonization and an oral antibiotic, doxycycline; follow-up post treatment collection sample was done to verify decolonization prior to next clinical rotation.

MAIN OUTCOME MEASURES: Screening for Staphylococcus aureus and MRSA identification; confirmation and antibiotic susceptibility by Vitek 2; self-administered questionnaires delineating demographics and risk factors; panel logistic regression models by Stata version 13

RESULTS: MRSA colonization did not increase. S. aureus incidence was 17.7 – 26.4%. Staphylococcal species incidence other than S. aureus increased (9.2 – 82.3%). The following odds ratio (OR) associations were found to be statistically significant: boil or skin infections with S. aureus (OR = 2.94, p < .01), working or volunteering in a healthcare facility odds with species other than S. aureus (OR = 4.41, p < .01) and gym and sports facilities odds with S. other (OR 2.45, p < .01). The most frequently occurring species at Wave 5 was S. hominis (21 isolates) while the most frequently occurring species at Wave 6 was S. epidermidis (25 isolates).

CONCLUSIONS: MRSA colonization did not increase during longitudinal study. S. aureus colonization remained fairly stable throughout the study (17 – 26%). Species colonization with non S. aureus species (e.g. S. hominis, S. epidermis, S. haemolyticus) increased significantly (9.2 – 82.3%) during clinical rotations. Knowledge of infection control and compliance may have contributed to an absence of MRSA colonization; however, the colonization by other staphylococci has been shown to be a risk factor for MRSA acquisition.

ABBREVIATIONS: MRSA = Methicillin-resistant Staphylococcus aureus; CA-MRSA = Community-associated methicillin resistant Staphylococcus aureus; HA-MRSA = Healthcare-associated methicillin resistant Staphylococcus aureus; MSSA = methicillin-sensitive Staphylococcus aureus; CLS = Clinical Laboratory Science; OR = odds ratio; CI = Confidence Interval; HCWs = Healthcare Workers; HAIs = Healthcare Associated Infections