Microbiological spectrum and susceptibility pattern of clinical isolates from the neonatal unit in a single medical center

Adv Clin Exp Med. 2015 Jan-Feb;24(1):15-22. doi: 10.17219/acem/38170.


Background: Infections are a frequent and significant cause of morbidity and mortality in neonatal units. The bacterial pathogens and their susceptibility patterns should be monitored in hospital settings. The aim of the study was to describe the distribution of the bacterial agents and their antibiotic resistant and susceptibility patterns in the Special Neonatal Care Unit (SNCU).

Material and methods: A retrospective analysis of results of microbiologically tested samples (blood, cerebrospinal fluid, urine, stool, eye excretions, external ear swabs, nasopharyngeal swabs and skin swabs) taken from newborns hospitalized in one SNCU in Warsaw (Poland) was conducted. The period analyzed was from July 1st, 2010 to December 31st, 2010.

Results: A total of 838 cultured samples were collected in the period analyzed. Three hundred seventy three of them (44.5%) were positive. The majority of the cultured microorganisms were classified as colonization: 338/373 (91%) strains. Gram negative bacteria were predominant colonizing flora: 227/338 (67%) strains. Gram positive bacteria were predominant causative agents in newborns with infections: 26/35 (74%) strains. 57.9% of Escherichia coli isolates were resistant to amoxicillin and ampicillin. 100% of Klebsiella pneumoniae were resistant to amikacin and netilmicin. Staphylococcus aureus methicillin resistant strains were cultured in 2.7% of cases.

Conclusions: Gram negative species continue to be predominant agents of neonatal colonizing flora while gram positive bacteria remain important causative agents for symptomatic infections. Continuous monitoring of bacterial flora and its antibiotic susceptibility pattern is necessary to provide a successful antibiotic policy. Current results may be used for future national and international comparison.

MeSH terms

  • Amikacin / therapeutic use
  • Amoxicillin / therapeutic use
  • Ampicillin / therapeutic use
  • Anti-Bacterial Agents / therapeutic use*
  • Body Fluids / microbiology
  • Drug Resistance, Bacterial / physiology*
  • Enterobacteriaceae Infections / drug therapy
  • Enterobacteriaceae Infections / microbiology
  • Escherichia coli / drug effects*
  • Escherichia coli / growth & development
  • Escherichia coli / isolation & purification
  • Female
  • Humans
  • Infant, Newborn
  • Intensive Care Units, Neonatal / statistics & numerical data*
  • Klebsiella pneumoniae / drug effects*
  • Klebsiella pneumoniae / growth & development
  • Klebsiella pneumoniae / isolation & purification
  • Male
  • Microbial Sensitivity Tests
  • Netilmicin / therapeutic use
  • Retrospective Studies
  • Staphylococcal Infections / drug therapy
  • Staphylococcal Infections / microbiology
  • Staphylococcus aureus / drug effects*
  • Staphylococcus aureus / growth & development
  • Staphylococcus aureus / isolation & purification


  • Anti-Bacterial Agents
  • Netilmicin
  • Ampicillin
  • Amoxicillin
  • Amikacin