Staphylococcus aureus biofilm formation at the physiologic glucose concentration depends on the S. aureus lineage

Abstract

BackgroundSince bacteria embedded in biofilms are far more difficult to eradicate than planktonic infections, it would be useful to know whether certain Staphylococcus aureus lineages are especially involved in strong biofilm formation. For this reason, in vitro biofilm formation of 228 clinical S. aureus isolates of distinct clonal lineages was investigated.ResultsAt 0.1% glucose, more than 60% of the S. aureus strains associated with multilocus sequence typing (MLST) clonal complex (CC)8 produced large amounts of biomass, compared to 0-7% for various other clonal lineages. Additionally, S. aureus bloodstream isolates associated with MLST CC8 and CC7 had similar biofilm forming capacities as their commensal counterparts. Furthermore, strong biofilm formation could not be attributed to a specific accessory gene regulator (agr) genotype, as suggested previously. The agr genotypes were strictly associated with the clonal lineages. Moreover, strong biofilm formation was not related to slime formation. Congo red agar (CRA) screening is therefore not useful as a qualitative screening method for biofilm formation.ConclusionThe adherence to polystyrene surfaces under physiologic glucose concentration (0.1%) was dependent on the clonal lineage. Strains associated with MLST CC8 were markedly more often classified as strong biofilm former at glucose concentrations of 0%, 0.1% and 0.25%.The present study reveals that the MLST CC8 associated genetic background was a predisposing factor for strong biofilm formation in vitro, under all tested glucose concentrations.

Biofilm formation in invasive Staphylococcus aureus isolates is associated with the clonal lineage

“…In contrast to our findings, they found spa type t037 (ST239-CC8-IIIA) strains form strong biofilms (Atshan et al, 2012a,b). Croes et al suggested that MLST CC8 was a predisposing factor for a strain to produce strong biofilms (Croes et al, 2009). Furthermore, the Brazilian clone (also MLST CC8) was shown to have increased adherence (Amaral et al, 2005).…”

“…Another limiting factor was not using supplementary glucose in the biofilm assay. This may influence the MRSA biofilm formation (Croes et al, 2009;O'Neill et al, 2007). Although we did analyse our collection by methicillin resistance and source of bacteraemia, these were secondary objectives.…”

“…In the recent literature, differences in biofilm formation were found to be due to the staphylococcus protein A (spa) lineage (Atshan et al, 2012a). Other studies found strong biofilm formation correlated with multilocus sequence typing (MLST) clonal complexes (Croes et al, 2009) or Staphylococcal Chromosome Cassette mec (SCCmec) typing (Lim et al, 2013).…”

Prevalence of blaZ gene and other virulence genes in penicillin-resistantStaphylococcus aureus isolated from bovine mastitis cases in Gansu, China

“…In some isolates, phenotypic resistance may have been caused by point mutations rather than gene acquisition. Additionally, except for the general resistance mechanisms (14), other pathways such as biofilm formation may play a major role in the resistance mechanisms (15).…”

Biofilm and Diabetic Foot Infections

“…Ayrıca glukozun bakteriler tarafından kullanılması EPS ekspresyonunu artırarak biyofilm oluşumunu artırır (12). Farklı bakteri kökenleriyle yapılmış bir çalışmada yüksek glukoz konsantrasyonunun (1000 mg/dl) biyofilm oluşumunu artırdığı; yine bir çalışmada metisiline dirençli ve duyarlı Staphylococcus aureus suşlarında 250 ve 500 mg/ dl glukoz düzeylerinin biyofilm oluşumunu artırdığı in vitro olarak gösterilmiştir (13).…”