Risk Factors for Infection with Coagulase-Negative Staphylococci in Newborns from the Neonatal Unit of a Brazilian University Hospital

Abstract

Background:Coagulase-negative staphylococci (CoNS) are one of the most frequent causative agents of neonatal nosocomial infections, especially in premature and low-weight newborns. Risk factors for infection include extracellular polysaccharide production and consequent biofilm formation that permit adhesion to the smooth surface of catheters and other medical devices. The objective of this study was to identify CoNS strains isolated from 105 newborns admitted to the Neonatal Unit of our hospital, and to evaluate the association of biofilm production and host risk factors with the occurrence of infection.Methods:CoNS isolates were identified and classified as significant or contaminant based on clinical and laboratory data of the newborn medical records. Perinatal risk factors for infection, neonatal clinical evolution, and antibiotic treatment were analysed. In addition, the presence of genes (icaA, icaC and icaD) responsible for biofilm production in CoNS was investigated.Results:Among the 130 CoNS strains studied, 66 (50.8%) were classified as clinically significant and 64 (49.2%) as contaminant. There was no difference in the detection of biofilm-specific genes between CoNS strains isolated from newborns with (81.8%) and without infection (84.3%), although 11 (91.7%) of the 12 children whose death was related to CoNS were infected with strains that were positive for these genes. Forty-five (83.3%) of the 54 newborns infected with CoNS were premature and 33 (61.1%) had a birth weight ≤ 1,500 g. Most newborns infected with CoNS had been submitted to invasive procedures, including catheter use (85.2%), parenteral nutrition (61.1%), and mechanical ventilation (57.4%). S. epidermidis was the most frequently isolated species (81.5%) and was more related to infection (86.3%) than to contamination (76.5%).Conclusion:Most newborns infected with CoNS presented factors that contributed to the colonization and development of infection with these microorganisms, including a birth weight ≤ 1,500 g, catheter complications, use of a drain, and previous antibiotic treatment. The fact that most children who died of CoNS-related infection carried strains positive for biofilm-specific genes indicates the importance of this virulence factor for the outcome of staphylococcal infections.

Prevalence and Antibiotic Susceptibility of Coagulase Negative Staphylococci in Tertiary Care Centre

“…This is followed by S.saprophyticus & S.haemolyticus and S.hominis, S.lugdenensis and finally S.xylosus. Our results are consistent with studies performed by Prapti Bora et al, [3], Akinkunmi E OA et al, [11], de Oliveira et al, [12], Sheikh A MM et al, [13]. CONS have been isolated from various medical devices used in these units, from NICU environment and paediatric wards [9].CONS are more prevalent in female population with 61% than in males with 39%.The prevalence of CONS is more common among people of age groups between 20-39yrs followed by people of age group between 40-59yrs, followed by 60-79yrs ,followed by 0-19 yrs.…”

“…While bacteria continue to acquire resistance to antibiotics, selection of the appropriate agents is of great importance. Our results are consistent with the results observed by other institutions and studies done by Akinkunmi et al, [11], de Oliveira A et al, [12]. The possible reasons of a high resistance rate in general and to oxacillin specifically; especially in the species that were isolated from catheter tips and blood cultures is long hospitalization periods, extensive use of antibiotics and the ability of these organisms to create multilayered bio-films on artificial surfaces [8].…”

“…Patients clinical case, age and type of causative agent identified may be the reason behind high resistance rate of CONS species that were isolated from the ICU and the paediatric wards [11,12,14].…”

“…Department wise distribution of CONS Fig-2 depicts the speciation of CONS isolated. Out of 76 isolates of CONS, S.epidermidis is most prevalent (27 no) followed by S.saprophyticus (21) S.haemolyticus(12), S.hominis(5), S.lugdenensis(9) and finally S.xylosus(2).…”

Comparative activity of ceftobiprole against coagulase-negative staphylococci from the BSAC Bacteraemia Surveillance Programme, 2013–2015

“…Coagulase-negative staphylococci (CoNS) are ubiquitous colonisers of human skin and mucous membranes that have the potential to cause clinically significant infections [ 1 ]. CoNS are a major cause of nosocomial infection, with a particular risk in premature newborns, patients with neutropenia and patients undergoing invasive procedures [ 1 – 3 ]. Due in part to their affinity for synthetic substrates and ability to form biofilms, CoNS are a frequent cause of device-related local and systemic infections [ 1 ].…”