Antimicrobial susceptibility of microorganisms isolated from sputum culture of patients with cystic fibrosis: Methicillin-resistant Staphylococcus aureus as a serious concern.
BACKGROUND
Infection is a major cause of morbidity and mortality in patients with cystic fibrosis (CF). Antimicrobial resistance of the bacterial spp. particularly methicillin resistance in Staphylococcus aureus has caused a lot of attention. The aim of this study was to describe the prevalence of S. aureus, Pseudomonas aeruginosa and Burkholderia cepacia-complex as well as their antimicrobial susceptibility patterns in CF patients in an Iranian referral pediatrics Hospital.


METHODS
From March 2011 until February 2012, 172 samples were collected at the Children Medical Center (CMC), an Iranian referral hospital in Tehran, Iran. Sputum specimens were cultured for the following bacterial pathogens: P. aeruginosa, S. aureus, B. cepacia complex. Antimicrobial susceptibility was performed according to the Clinical Laboratory Standards Institute recommendations.


RESULTS
In our study, 54% of the patients (n = 93) harbored at least once S. aureus, 30% (n = 52) P. aeruginosa, and 2% (n = 3) Burkholderia cepacia. In 40 patients (23%), none of these organisms was grown. An increasing colonization rate of P. aeruginosa in the second decade of life was found. In contrast, the colonization rate of S. aureus was constant in both decades of life. Methicillin resistant S. aureus (MRSA) was detected in 40 isolates (43%). Among MRSA, no resistance against vancomycin, linezolid and quinupristin/dalfopristin occurred. The susceptibility of P. aeruginosa isolates to meropenem, imipenem, doripenem, levofloxacin and polymixin B were more than 90%.


CONCLUSIONS
The prevalence of MRSA has been rising. Since its impact on clinical outcomes, optimal prevention and treatment strategies are unclear, further studies to expand the knowledge about the infection control strategies and MRSA treatment are highly recommended.
Department of Pediatric Infectious Disease, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Narges
N
Mazloomi Nobandegani
Pediatric Infectious Diseases Research Center, Tehran University of Medical Sciences, Tehran, Iran.
Shima
S
Mahmoudi
Pediatric Infectious Diseases Research Center, Tehran University of Medical Sciences, Tehran, Iran.
Babak
B
Pourakbari
Pediatric Infectious Diseases Research Center, Tehran University of Medical Sciences, Tehran, Iran.
Reihaneh
R
Hosseinpour Sadeghi
Department of Pediatric Gastroenterology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Mehri
M
Najafi Sani
Department of Pediatric Gastroenterology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Fateme
F
Farahmand
Department of Pediatric Gastroenterology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Farzaneh
F
Motamed
Department of Pediatric Infectious Disease, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Raheleh
R
Nabavizadeh Rafsanjani
Department of Pediatric Infectious Disease, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Pediatric Infectious Diseases Research Center, Tehran University of Medical Sciences, Tehran, Iran. Electronic address: smamishi@sina.tums.ac.ir.
Setareh
S
Mamishi
D000293:Adolescent; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001424:Bacterial Infections / Q000453:epidemiology / Q000382:microbiology*; D042602:Burkholderia cepacia complex / Q000187:drug effects* / Q000302:isolation & purification; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000150:complications*; D005260:Female; D006801:Humans; D007223:Infant; D007492:Iran; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D015995:Prevalence; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000302:isolation & purification; D013183:Sputum / Q000382:microbiology*
D000900:Anti-Bacterial Agents
Cystic fibrosis; Methicillin resistant S. aureus; P. aeruginosa