Antibiotic resistance among bacterial conjunctival pathogens collected in the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) surveillance study.

Penny A Asbell,Heleen H Decory,Massimiliano Galdiero

doi:10.1371/journal.pone.0205814

Penny A Asbell, Heleen H Decory + Show 1 more

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https://doi.org/10.1371/journal.pone.0205814

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Journal: PloS one	Publication Date: Oct 18, 2018
Citations: 35	License type: CC BY 4.0

Affiliation: Icahn School of Medicine at Mount Sinai

Abstract

The Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) surveillance study evaluates in vitro antibiotic resistance among Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae isolates from ocular infections. Here we report resistance rates and trends among conjunctival-sourced ocular isolates collected across the US from 2009 through 2016. A total of 1198 conjunctival isolates (483 S. aureus, 305 CoNS, 208 H. influenzae, 118 S. pneumoniae, and 84 P. aeruginosa) were collected from patients with presumed bacterial conjunctivitis from 57 sites across 40 states. A large proportion of staphylococci demonstrated resistance to oxacillin and azithromycin, while resistance was low against the majority of antibiotics tested for S. pneumoniae, P. aeruginosa, and H. influenzae. Multidrug resistance (≥3 antibiotic classes) was found in 30.2% of S. aureus and 39.0% of CoNS isolates, and methicillin resistance more than doubled the rate of multi-drug resistance (methicillin-resistant S. aureus [MRSA], 76.5%; methicillin-resistant CoNS isolates, 72.8%). There was a pattern of increasing mean percent resistance with increasing age by decade of life among S. aureus, MRSA, and CoNS (P≤0.038). Over the eight-year study period, there were small yet significant decreases in resistance rates among S. aureus to azithromycin, ciprofloxacin, tobramycin, trimethoprim, and oxacillin (P≤0.003), and among CoNS and P. aeruginosa (both P<0.05) to ciprofloxacin. These data indicate that antibiotic resistance is high, but did not increase, among conjunctival-sourced isolates collected in the US from 2009 through 2016. For certain antibiotic/pathogen combinations, there was a trend of decreased resistance, including a decrease in oxacillin resistance among S. aureus.

Highlights

Conjunctivitis is a common ocular infection affecting all age groups [1]
A total of 1198 isolates (483 S. aureus, 305 coagulase-negative staphylococci (CoNS), 208 H. influenzae, 118 S. pneumoniae, and 84 P. aeurginosa) from the conjunctiva were collected from 57 participating centers across 40 states in the US
The lowest MIC90s among all tested antibiotics were for besifloxacin (MSSA, 0.25 μg/mL; MRSA, 4 μg/mL) and vancomycin (MSSA and MRSA, both 1 μg/mL)

Summary

Introduction

While a viral etiology is responsible for the majority of adult cases, bacterial conjunctivitis is the second most common cause in adults and may be the primary cause in children [2,3]. Causative bacterial agents among adults are most frequently staphylococcal species, followed by Streptococcus pneumoniae and Haemophilus influenzae, with Pseudomonas aeruginosa common in contact lens wearers [4,5,6]. H. influenzae is the most common pathogen, followed by S. pneumoniae, Staphylococcus aureus, and Staphylococcus epidermidis [7,8,9,10]. While bacterial conjunctivitis is generally self-limiting, treatment with topical antibiotics is associated with earlier clinical and microbiological remission, as well as decreased discomfort and morbidity [1,9,11,12]. Antibiotic therapy is typically initiated empirically, with guidelines recommending cultures only in severe, chronic, recurrent, or treatment-unresponsive cases [1]

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