title: Prevalence of antibiotic resistance in multi-drug resistant coagulase-negative staphylococci isolated from invasive infection in very low birth weight neonates in two Polish NICUs.
abstract: BACKGROUND
  Multi-drug resistant coagulaso-negative staphylococci (CNS) have become an increasing problem in nosocomial infections connected with the presence of medical devices. The paper aimed to analyze the prevalence of antibiotic resistance in CNS isolated from invasive infection in very low birth weight (VLBW) neonates.
  
  
  METHODS
  Continuous prospective target surveillance of infections was conducted in 2009 at two Polish NICUs that participated in the Polish Neonatology Surveillance Network (PNSN). The study covered 386 neonates with VLBW (≤1500 g), among which 262 cases of invasive infection were detected with predominance of CNS (123; 47%). Altogether, 100 CNS strains were analyzed. The resistance phenotypes were determined according to EUCAST. Resistance genes: mecA, ermA, ermB, ermC, msrA, aac(6')/aph(2''), ant(4')-Ia and aph(3')-IIIa were detected using multiplex PCR.
  
  
  RESULTS
  The most common species was S. epidermidis (63%), then S. haemolyticus (28%) and other CNS (9%). Among S. epidermidis, 98% of isolates were resistant to methicillin, 90% to erythromycin, 39% to clindamycin, 95% to gentamicin, 60% to amikacin, 36% to ofloxacin, 2% to tigecycline, 3% to linezolid and 13% to teicoplanin. Among S. haemolyticus isolates, 100% were resistant to methicillin, erythromycin and gentamicin, 18% to clindamycin, 50% to amikacin, 86% to ofloxacin, 14% to tigecycline and 4% to teicoplanin. No resistance to linezolid was detected for S. haemolyticus isolates. Moreover, all isolates of S. epidermidis and S. haemolyticus were susceptible to vancomycin. The mecA gene was detected in 98% of S. epidermidis isolates and all of S. haemolyticus ones. Among macrolide resistance isolates, the ermC was most common in S. epidermidis (60%) while msrA was prevalent in S. haemolyticus (93%). The ermC gene was indicated in all isolates with cMLSB, whereas mrsA was found in isolates with MSB phenotype. Of the aminoglycoside resistance genes, aac(6')/aph(2'') were present alone in 83% of S. epidermidis, whereas aac(6')/aph(2'') with aph(3')-IIIa were predominant in 84% of S. haemolyticus.
  
  
  CONCLUSIONS
  Knowing the epidemiology and antibiotic resistance of CNS isolated from invasive infection in VLBW neonates is a key step in developing targeted prevention strategies and reducing antibiotic consumption.
authors.affiliation: Department of Bacteriology, Microbial Ecology and Parasitology, Chair of Microbiology, Jagiellonian University Medical College, Czysta Street 18, 31-121, Krakow, Poland. mbrzych@cm-uj.krakow.pl.
authors.forename: Monika
authors.initials: M
authors.lastname: Brzychczy-Wloch
authors.forename: Maria
authors.initials: M
authors.lastname: Borszewska-Kornacka
authors.forename: Ewa
authors.initials: E
authors.lastname: Gulczynska
authors.forename: Jadwiga
authors.initials: J
authors.lastname: Wojkowska-Mach
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Sulik
authors.forename: Monika
authors.initials: M
authors.lastname: Grzebyk
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Luchter
authors.forename: Piotr B
authors.initials: PB
authors.lastname: Heczko
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Bulanda
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial; D005798:Genes, Bacterial; D006801:Humans; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight; D007363:Intensive Care Units, Neonatal; D008826:Microbial Sensitivity Tests; D060885:Multiplex Polymerase Chain Reaction; D011044:Poland; D015995:Prevalence; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013210:Staphylococcus / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents