Antibiotic Resistance of Commensal Staphylococcus aureus and Coagulase-Negative Staphylococci in an International Cohort of Surgeons: A Prospective Point-Prevalence Study.

Mario Morgenstern,Simon Hackl,Volker Bühren,Christoph Erichsen,R Geoff Richards,Sven Hungerer,Julia Mily,Jan Friederichs,Matthias Militz,T Fintan Moriarty,Virginia Post,Stephen L Kates,Jose Melo-Cristino

doi:10.1371/journal.pone.0148437

Abstract

Nasal colonization with antibiotic resistant bacteria represents both a risk factor for the colonized individual and their immediate contacts. Despite the fact that healthcare workers such as orthopedic surgeons are at a critical interface between the healthcare environment and an at-risk patient population, the prevalence of antibiotic resistant bacteria within the surgical profession remains unclear. This study offers a snapshot of the rate of nasal colonization of orthopedic surgeons with multi-resistant staphylococci including methicillin-resistant S. aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCoNS). We performed a prospective, observational study obtained at a single time point in late 2013. The participants were active orthopedic, spine and head & neck surgeons from 75 countries. The prevalence of nasal carriage of the different bacteria and the corresponding 95% confidence interval were calculated. From a cohort of 1,166 surgeons, we found an average S. aureus nasal colonization rate of 28.0% (CI 25.4;30.6) and MRSA rate of 2.0% (CI 1.3;2.9), although significant regional variations were observed. The highest rates of MRSA colonization were found in Asia (6.1%), Africa (5.1%) and Central America (4.8%). There was no MRSA carriage detected within our population of 79 surgeons working in North America, and a low (0.6%) MRSA rate in 657 surgeons working in Europe. High rates of MRCoNS nasal carriage were also observed (21.4% overall), with a similar geographic distribution. Recent use of systemic antibiotics was associated with higher rates of carriage of resistant staphylococci. In conclusion, orthopedic surgeons are colonized by S. aureus and MRSA at broadly equivalent rates to the general population. Crucially, geographic differences were observed, which may be partially accounted for by varying antimicrobial stewardship practices between the regions. The elevated rates of resistance within the coagulase-negative staphylococci are of concern, due to the increasing awareness of their importance in hospital acquired and device-associated infection.

Highlights

Staphylococcus aureus and coagulase-negative staphylococci (CoNS) are both commensal and opportunistic pathogens, colonizing humans with an estimated prevalence of 30% and 100% respectively [1, 2]. These microorganisms are generally associated with asymptomatic skin and mucosal carriage, yet are paradoxically recognized as amongst the most frequent causative agents of hospital-associated infection (HAI) and device-associated infection (DAI) [3,4,5]
To explore the issue of colonization with antibiotic resistant bacteria within the surgical profession, we have prospectively evaluated the nasal carriage of staphylococci with their antibiotic resistance profiles in a large international cohort of active orthopedic, spine and head & neck surgeons
We found that antibiotic therapy simultaneously reduced the rate of MSSA colonization, and increased the rate of methicillin-resistant S. aureus (MRSA) and MRCoNS colonization compared with the remaining surgeons

Summary

Introduction

Staphylococcus aureus and coagulase-negative staphylococci (CoNS) are both commensal and opportunistic pathogens, colonizing humans with an estimated prevalence of 30% and 100% respectively [1, 2] These microorganisms are generally associated with asymptomatic skin and mucosal carriage, yet are paradoxically recognized as amongst the most frequent causative agents of hospital-associated infection (HAI) and device-associated infection (DAI) [3,4,5]. Antibiotic resistant strains, such as methicillin-resistant S. aureus (MRSA), have emerged as a significant threat in both the hospital and community environment [6]. Methicillin resistance is frequently observed within the CoNS (MRCoNS), in surgical site infection (SSI) and DAI, where biofilm formation on implants and on tissue further reduces treatment success [10]

Objectives

Methods

Results

Conclusion