674. A Decade of Antimicrobial Resistance of Staphylococcus aureus (SA) in Cystic Fibrosis (CF): A Widespread Problem!
Session: Poster Abstract Session: They've Been Here a Billion Years! Pediatric Bacterial and Viral Infections
Thursday, October 27, 2016
Room: Poster Hall

Background: SA is a major pathogen in children with CF. Antibiotic treatment for pulmonary exacerbations and methicillin-resistant SA (MRSA) eradication may impact antimicrobial resistance. Our objectives were to determine 1) rates of antimicrobial resistance among all SA isolates from patients with CF at Nationwide Children’s Hospital (NCH) and its change over time (2005-2014), and 2) resistance rates by specimen types (bronchoalveolar lavage [BAL], sinus, throat/sputum) and age groups (<1, 1-5, 6-18, >18 years).

Methods: Retrospective review of the antimicrobial susceptibilities of all SA isolates obtained from the respiratory tract of patients with CF (inpatients/outpatients) that were performed in the NCH Microbiology Laboratory from 1/2005-12/2014

Results: From 2005-2014 among 12,447 SA isolates, resistance to methicillin (45%), doxycycline (7%) and linezolid (1%) increased significantly over time (p<0.05), while resistance to trimethoprim-sulfamethoxazole (TMP-SMX, 7%) and doxycycline (7%) remained unchanged and resistance to clindamycin (59%) decreased (Figures 1-3). Resistance rates for all agents were significantly higher among MRSA than methicillin-susceptible SA (MSSA) isolates (Table). Methicillin, clindamycin, TMP/SMX, doxycycline and erythromycin resistance rates were higher among isolates from BAL specimens when compared to sinus and sputum/throat samples (p<0.05). Resistance rates for all agents except linezolid were significantly higher with increasing age group (p<0.0001).

Conclusion: In the past decade, overall resistance to antimicrobial agents in SA isolates from CF patients remained high, especially in MRSA.  Methicillin, doxycycline and linezolid resistance increased significantly, while resistance rates to all drugs except linezolid were significantly higher in older children and adults. The clinical and stewardship impact of these resistance patterns in CF patients is substantial.

 

Table. Overall antimicrobial resistance among SA isolates from CF patients (any site)

Antibiotic

Resistance Rate (%)

p-value

SA

MRSA

MSSA

Clindamycin

59

82

41

<0.0001 

TMP-SMX

7

12

3

<0.0001 

Doxycycline

7

11

4

<0.0001 

Linezolid

0.1

0.2

0

 0.008

Erythromycin

72

94

53

 <0.0001


 

Claudia Vicetti Miguel, MD, Pediatrics, Nationwide Childrens Hospital, Columbus, OH, Asuncion Mejias, MD, PhD, Center for Vaccines and Immunity, The Research Institute at Nationwide Children's Hospital, Columbus, OH, Amy Leber, PhD, Department of Laboratory Medicine, Nationwide Children's Hospital, Columbus, OH and Pablo J. Sanchez, MD, FIDSA, FPIDS, Pediatrics, Divisions of Pediatric Infectious Diseases and Neonatology, Nationwide Children's Hospital - Ohio State University College of Medicine, Columbus, OH

Disclosures:

C. Vicetti Miguel, None

A. Mejias, Janssen: Grant Investigator and Scientific Advisor , Consulting fee and Research grant
Alios: Consultant , Consulting fee
Abbvie: CME lecture , Speaker honorarium
Novartis: CME lecture , Speaker honorarium
Gilead: Grant Investigator , Grant recipient

A. Leber, None

P. J. Sanchez, AbbVie, Inc: Scientific Advisor , Speaker honorarium

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