Pathogenic factors and antimicrobial resistance of Staphylococcus epidermidis associated with nosocomial infections occurring in intensive care units

Abstract

Nosocomial infections constitute an important problem in hospitals, intensive care units (ICU) having the highest incidence of this type of infection. Staphylococci, especially Staphylococcus epidermidis and Staphylococcus aureus, are among the most important microorganisms associated with nosocomial infections. S. epidermidis is a common skin resident, and can be introduced into the clinical environment by patients and hospital staff. The situation in hospitals is aggravated by the emergence of multiresistant strains. We evaluated 98 hospital S. epidermidis isolates collected at neonatal, pediatric and adult ICUs and 20 S. epidermidis control skin resident isolates from healthy volunteers, for resistance to ten antibiotics and chemotherapeutic agents, and other pathogenicity factors. A high frequency (76.5%) of multiresistance was detected in clinical isolates, whereas community isolates were resistant to penicillin and ampicillin only. The frequency of multiresistant strains was 67.7% in the neonatal ICU, 66.6% in the pediatric ICU and 60.8% in the adult ICU, the lower frequency of multiresistant isolates in the adult ICU indicates a higher incidence of community strains in this unit. There were significantly higher frequencies of hemolytic, proteolytic and biofilm-forming isolates in the clinical isolates than the community isolates, indicating a higher incidence of strains with pathogenic potential in the hospital environment. Except for slight correlation with hemolytic activity there was no correlation between antibiotic multiresistance and pathogenicity factors.

16S rRNA gene-based identification of bacteria in postoperative endophthalmitis by PCR- Denaturing Gradient Gel Electrophoresis (PCR-DGGE) fingerprinting

“…The icaA gene participates in biofilm development, one important factor in pathogenesis of this bacterium, while mecA gene is involved in resistance to methicillin antibiotic. Our results were similar to the reported by previous works, which have detected Identification of bacteria in postoperative endophthalmitis virulence factor genes in S. epidermidis strains isolated from clinical cases but not in commensal strains (8,10,12).…”

Prevalência de Staphylococcus spp resistentes à meticilina isolados em uma maternidade escola da Cidade de Natal, Estado do Rio Grande do Norte

“…Vários trabalhos relatam o envolvimento de CNS em processos infecciosos de próteses, implantes, cateteres venosos e outros dispositivos cirúrgicos, porém o isolamento de cepas de Staphylococcus epidermidis em hemoculturas tem se tornado rotina na maioria dos hospitais, e revela ser esse um dos principais agentes causadores de bacteremia 8 .…”

“…Vale ressaltar que sua importância não diz respeito apenas à freqüência, mas também ao seu potencial de gravidade nas infecções hospitalares e a sua forma de disseminação 15 . Esses aspectos têm fundamento e despertam preocupação, ao passo que, assim como o paciente, a equipe que o acompanha pode estar colonizada pela cepa, especialmente na mucosa e na pele, o que acarreta uma maior chance de contaminação ou reinfecção 8 .…”

“…A elevada transmissibilidade de genes de resistência entre linhagens e o uso abusivo de drogas antimicrobianas têm se constituído em importantes fatores na seleção de amostras multirresistentes 2 . Associados ao mecanismo de resistência à meticilina também podem ser citados a produção de invasinas, toxinas e a formação de biofilme 8 .…”

Genetic similarity between staphylococcus sp isolated from human and hospital settings, and susceptibility to different antimicrobials

“…These antimicrobials have been reported for the treatment of staphylococci infections, in a CLSI document (6). Strains resistant to more than six antimicrobials were considered to be multiresistant (23).…”