Staphylococcus epidermidis and Staphylococcus haemolyticus: Molecular Detection of Cytotoxin and Enterotoxin Genes

Abstract

Although opportunistic pathogens, coagulase-negative staphylococci (CoNS), including Staphylococcus epidermidis and Staphylococcus haemolyticus, have long been regarded as avirulent organisms. The role of toxins in the development of infections caused by CoNS is still controversial. The objective of this study was to characterize the presence of enterotoxin and cytotoxin genes in S. epidermidis and S. haemolyticus isolates obtained from blood cultures. Cytotoxin genes were detected by PCR using novel species-specific primers. Among the 85 S. epidermidis and 84 S. haemolyticus isolates, 95.3% and 79.8%, respectively, carried at least one enterotoxin gene. The most frequent enterotoxin genes were sea (53.3%), seg (64.5%) and sei (67.5%). The seg gene was positively associated with S. epidermidis (p = 0.02), and this species was more toxigenic than S. haemolyticus. The hla/yidD gene was detected in 92.9% of S. epidermidis and the hla gene in 91.7% of S. haemolyticus isolates; hlb was detected in 92.9% of the S. epidermidis isolates and hld in 95.3%. Nosocomial Staphylococcus epidermidis and S. haemolyticus isolates exhibited a high toxigenic potential, mainly containing the non-classical enterotoxin genes seg and sei. The previously unreported detection of hla/yidD and hlb in S. epidermidis and S. haemolyticus using species-specific primers showed that these hemolysin genes differ between CoNS species and that they are highly frequent in blood culture isolates.

Identification of hemolysin encoding genes and their association with antimicrobial resistance pattern among clinical isolates of coagulase-negative Staphylococci

“…However, there are reports of the occurrence of decreased susceptibility to vancomycin in CoNS isolates [34,35]. Out of the 91 CoNS isolates, the percentage of strains with hemolytic activity were the highest among S. epidermidis (53.8%), followed by S. haemolyticus (39.5%) which is in agreement with the findings of Cunha et al, and Pinheiro et al, [36,37], but, in contrary with the findings of Akinkunmi et al, [20]. Among CoNS species, 94.6% and 81.6% of the S. haemolyticus and S. epidermidis strains were determined to be positive to the hla gene, respectively.…”

“…Among CoNS species, 94.6% and 81.6% of the S. haemolyticus and S. epidermidis strains were determined to be positive to the hla gene, respectively. [37,38]. In this study, the largest number of the strains carrying the hld gene belonged to S. epidermidis with frequency of 69.4%, then S. hemolyticus (37.8%), according to Pinheiro et al,95.3% of the S. epidermidis and none of the S. haemolyticus were carrying hld gene, [37].…”

Investigation of Glycopeptide Susceptibility of Coagulase-Negative Staphylococci (CoNS) From a Tertiary Care Hospital in Gorgan, Northern Iran

“…The current study revealed that S. haemolyticus and S. epidermidis were the most prevalent CoNS from clinical isolates. This result, in line with many previous studies, confirms the predominance of these two species in various clinical samples compared to other CoNS species (28)(29)(30)(31). In addition, S. haemolyticus and S. epidermidis have been reported to be among the most frequent CoNS species acquiring resistance to multiple antibiotics, which is in agreement with the results of the current study (3,8).…”

Avaliação Microbiológica dos Aparelhos Celulares dentro do Bloco Cirúrgico – Avaliação em um Hospital Beneficente de Pernambuco

“…Estafilococos também são encontrados regularmente em roupas comuns, de cama, e outros ambientes humanos. 15 Historicamente, enquanto as espécies coagulase-positivas foram consideradas como patógenos oportunistas, as espécies coagulase-negativas têm sido geralmente consideradas como não-patogênicas. No entanto, esta visão está mudando, especialmente porque tem havido uma crescente evidência de que algumas destas espécies podem ser potencialmente patogênicas para o ser humano através da produção de enterotoxina, causando infecções nosocomiais.…”