Biofilm Formation by Staphylococcus haemolyticus

Abstract

Infections due to coagulase-negative staphylococci (CoNS) most frequently occur after the implantation of medical devices and are attributed to the biofilm-forming potential of CoNS. Staphylococcus haemolyticus is the second most frequently isolated CoNS from patients with hospital-acquired infections. There is only limited knowledge of the nature of S. haemolyticus biofilms. The aim of this study was to characterize S. haemolyticus biofilm formation. We analyzed the biofilm-forming capacities of 72 clinical S. haemolyticus isolates. A detachment assay with NaIO 4 , proteinase K, or DNase was used to determine the main biofilm components. Biofilm-associated genes, including the ica operon, were analyzed by PCR, and the gene products were sequenced. Confocal laser scanning microscopy (CLSM) was used to elucidate the biofilm structure. Fifty-three isolates (74%) produced biofilms after growth in Trypticase soy broth (TSB) with glucose, but only 22 (31%) produced biofilms after growth in TSB with NaCl. It was necessary to dissolve the biofilm in ethanol-acetone to measure the optical density of the full biofilm mass. DNase, proteinase K, and NaIO 4 caused biofilm detachment for 100%, 98%, and 38% of the isolates, respectively. icaRADBC and polysaccharide intercellular adhesin (PIA) production were found in only two isolates. CLSM indicated that the biofilm structure of S. haemolyticus clearly differs from that of S. epidermidis. We conclude that biofilm formation is a common phenotype in clinical S. haemolyticus isolates. In contrast to S. epidermidis, proteins and extracellular DNA are of functional relevance for biofilm accumulation, whereas PIA plays only a minor role. The induction of biofilm formation and determination of the biofilm mass also needed to be optimized for S. haemolyticus.

Influence of papain in biofilm formed by methicillin-resistant Staphylococcus epidermidis and methicillin-resistant Staphylococcus haemolyticus isolates

“…In relation to MRSHa, 21 (70%) isolates were able to produce biofilm, of which 26.6% of them were classified to be a strong biofilm producer (Table I). Similar to our results, Fredheim et al (2009) found that 74% of the S. haemolyticus analyzed were able to produce biofilms. However, the biofilm formed by S. haemolyticus has not been subject to more detailed studies so far.…”

“…Previous studies have suggested that extracellular proteins seem to be one of the main components of the biofilm matrix formed by S. haemolyticus (Fredheim et al, 2009;Silva et al, 2013). Because of that, we expected papain to disrupt biofilm accumulation produced by MRSHa.…”

Clonality, virulence and the occurrence of genes encoding antibiotic resistance among Staphylococcus warneri isolates from bloodstream infections

“…The ability of the S. warneri strains to form biofilm on an abiotic surface was quantified essentially as described elsewhere (Kim et al, 2008;Fredheim et al, 2009). In brief, an overnight culture grown in tryptic soy broth (TSB; Difco, Beckton Dickinson) with 0.25 % glucose at 37 C was diluted 1 : 100 in the medium and 100 µl was transferred into 96-well polystyrene microtiter plates.…”

“…Detachment assay was performed as described by Fredheim et al (2009). The major components of S. warneri biofilms were analysed using sodium metaperiodate (NaIO 4 ) to degrade polysaccharide, proteinase K to degrade proteins and DNaseI to degrade DNA.…”

Staphylococcus haemolyticus – an emerging threat in the twilight of the antibiotics age

“…Most S. haemolyticus strains seem to lack the important virulence attributes. However, some enzymes, cytolysins or surface substances are indicated in the literature as factors contributing to its virulence (Daniel et al, 2014;Flahaut et al, 2008;Simango, 2005), but none of them was identified as a crucial and determinative factor (Fredheim et al, 2009). Despite this, S. haemolyticus is, after S. epidermidis, the second most frequently isolated CNS from clinical cases, particularly from blood infections, including sepsis (Becker et al, 2014;Klingenberg et al, 2007;Liakopoulos et al, 2008;Silva et al, 2013).…”