Molecular epidemiology of Staphylococcus epidermidis in neonatal intensive care units

Abstract

Late-onset sepsis (LOS) in preterm neonates is increasingly reported to be associated with gut-colonizing Staphylococcus epidermidis. We aimed to describe the molecular epidemiology of S. epidermidis colonizing the gut of neonates hospitalized in two neonatal intensive care units. S. epidermidis from rectal swabs were typed by multilocus variable-number tandem-repeat analysis (MLVA), randomly chosen isolates of predominant MLVA types additionally by multilocus sequence typing. Antimicrobial susceptibility, the presence of icaA, IS256, arginine catabolic mobile element (ACME), agr type, and SCCmec type were determined. Of 276 neonates (38.4%), 106 were colonized with S. epidermidis, yielding a total of 139 isolates (62 in one unit and 77 in another unit). Of the 55 MLVA types identified, the five predominant detected in both units corresponded to sequence type (ST) 2, ST5, and ST59 or its single locus variant ST81 and formed three major MLVA clonal complexes accounting for 74.8% of all isolates. Overall, the prevalence of mecA, icaA, IS256, and ACME was 91.4%, 28.1%, 64%, and 77%, respectively. Of the mecA-positive isolates (n = 127), 43.9% carried SCCmec type IV. Of eight episodes of LOS, four were caused by ST2 and two by ST5. Preventing gut colonization with nosocomial epidemic S. epidermidis in hospitalized neonates could contribute to the prevention of LOS.

Beyond sepsis: Staphylococcus epidermidis is an underestimated but significant contributor to neonatal morbidity

“…Besides indirect evidence linking S. epidermidis sepsis and gut injury, there is also direct evidence indicating that S. epidermidis was capable to translocate into the gut cavity through injured intestine [ 112 ]. Results from very recent studies corroborated this finding and demonstrated that the causative agent of LOS, including S. epidermidis , may correspond to the abundant bacterial genera in gut microbiome at the diagnosis of LOS [ 24 , 25 ]. The gut-colonizing S. epidermidis seems to be characterized by the carriage of pathogenic factors, such as icaA , IS 256 , SCC mec and toxins [ 25 , 66 ].…”

“…Recent data indicate that S. epidermidis may belong to the abundant bacterial genera in airway and gut microbiomes, especially of hospitalized preterm and term neonates [ 24-26 ]. Multilocus sequence typing (MLST), a nucleotide sequence based technology, is an advanced tool of investigating bacterial evolution and epidemiological pattern [ 8 , 25 , 27-30 ]. Current data demonstrate that S. epidermidis strains isolated from hospitalized neonates are not widely diverse among various regions, but are represented by a limited number of clones [ 8 , 25 , 28 , 30 ].…”

“…Multilocus sequence typing (MLST), a nucleotide sequence based technology, is an advanced tool of investigating bacterial evolution and epidemiological pattern [ 8 , 25 , 27-30 ]. Current data demonstrate that S. epidermidis strains isolated from hospitalized neonates are not widely diverse among various regions, but are represented by a limited number of clones [ 8 , 25 , 28 , 30 ]. The hands of health-care personnel are the major sources of S. epidermidis transmission among neonates [ 8 , 25 , 28 , 30 ].…”

“…Factors associated with nosocomial environmental, such as skin-breaching interventions, and individual susceptibility may contribute to the role switch of S. epidermidis from a commensal to a nosocomial pathogen [ 36 , 47 ]. According to investigations carried out in the last two decades, S. epidermids sequence type 2 (ST2) appears to be the most widespread nosocomial clone in neonatal ward, and may account for the majority of cases of neonatal sepsis [ 8 , 25 , 28 , 30 ]. ST2 is characterized by biofilm forming capacity, antibiotic resistance and a highly flexible genetic background [ 27-30 ].…”

Genotypic and Phenotypic Characterization of Fecal Staphylococcus epidermidis Isolates Suggests Plasticity to Adapt to Different Human Body Sites

“…Some lineages of S. epidermidis can cause infections, a phenomenon which has been associated with an increased density of antimicrobial resistance and virulence-related genes in the genomes of those disease-causing lineages (Soeorg et al, 2017). Such S. epidermidis have been shown to cause pathological changes in the kidney and liver of rats and mice, among other organs (Akinkunmi et al, 2014).…”