23
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Analysis of S. Epidermidis icaA and icaD genes by polymerase chain reaction and slime production: a case control study

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Background

          Staphylococcus epidermidis is a common pathogen in medical device-associated infections and have an ability to form adherent slime. We aimed to study the effects of icaA and icaD genes on the slime formation of Staphylococcus epidermidis associated with catheter-associated infections.

          Methods

          S. epidermidis isolates from the central venous catheter blood of patients with catheter-associated infections, and from the nasal vestibules of healthy volunteers, intensive care unit hospital staff, and patients, were collected. Slime phenotype was determined by Congo red agar test. The icaA/D was detected by polymerase chain reaction. Slime was examined using scanning electron microscopy.

          Results

          A total of 82 S. epidermidis isolates were collected. We found a statistically significant difference with regards to slime production between the clinical isolates from the catheter blood specimens and those from the nasal vestibules (p<0.05). All S. epidermidis slime positive strains isolated were icaA positive. There was a greater correlation between the presence of both icaA and icaD and the slime production than the single expression of icaA or icaD and the presence of slime in all groups. The co-expression of mecA and icaD was associated with enhanced resistance to antibiotics.

          Conclusion

          S. epidermidis bacteria are significant nosocomial pathogens, and icaA/D can clarify the adhesion mechanism in the pathogenesis of infections associated with medical devices. This study result could be useful for the development of rapid diagnosis for slime producing and methicillin resistant S. epidermidis strains.

          Related collections

          Most cited references27

          • Record: found
          • Abstract: found
          • Article: not found

          Coagulase-negative staphylococcal infections.

          Coagulase-negative staphylococci (CNS) are differentiated from the closely related but more virulent Staphylococcus aureus by their inability to produce free coagulase. Currently, there are over 40 recognized species of CNS. These organisms typically reside on healthy human skin and mucus membranes, rarely cause disease, and are most frequently encountered by clinicians as contaminants of microbiological cultures. However, CNS have been increasingly recognized to cause clinically significant infections. The conversion of the CNS from symbiont to human pathogen has been a direct reflection of the use of indwelling medical devices. This article deals with the clinical syndromes, epidemiology, prevention, and management of infections caused by this unique group of organisms.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Presence of icaA and icaD genes and slime production in a collection of staphylococcal strains from catheter-associated infections.

            Both Staphylococcus epidermidis and Staphylococcus aureus are important causes of infections associated with catheters and other medical devices. It has recently been shown that not only S. epidermidis but also S. aureus can produce slime and carries the ica operon responsible for slime production. In the operon, coexpression of icaA and icaD is required for full slime synthesis. In this study, the presence of icaA and icaD was determined in a collection of 91 staphylococcal (68 S. epidermidis and 23 S. aureus) strains from intravenous catheter-associated infections, in 10 strains from the skin and mucosa of healthy volunteers, and in two reference strains by a PCR method. Slime-forming ability was tested on Congo red agar plates; 49% of S. epidermidis strains from catheters and, surprisingly, 61% of S. aureus strains were icaA and icaD positive and slime forming. All the saprophytic strains turned out to be negative for both icaA and icaD and also non-slime forming. Two S. aureus and one S. epidermidis strain from catheters, detected as icaA and icaD positive by PCR analysis and as slime forming (black colonies) at 24 h on Congo red agar, at 48 h exhibited tiny red spikes at the center of black colonies. The onset of these variants could not be ascribed to a mutagenic potential of Congo red, which, in the Ames test, was devoid of mutagenicity. PCR analysis showed that these red variants were negative for both icaA and icaD and even lacking the entire icaADBC operon. The data reported indicate an important role of ica genes as a virulence marker in staphylococcal infections from intravenous catheters.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Role of coagulase-negative staphylococci in human disease.

              Coagulase-negative staphylococci (CNS) are normal inhabitants of human skin and mucous membranes. They have long been dismissed as culture contaminants, but now the potentially important role of CNS as pathogens and their increasing incidence has been recognized. Approximately 55-75% of nosocomial isolates is methicillin resistant. CNS were the first organisms in which glycopeptide resistance was recognized. In the immunocompetent host, CNS endocarditis and urinary tract infections with Staphylococcus saprophyticus are the most common CNS infections. Other patients are usually immunocompromised, with indwelling or implanted foreign bodies. CNS account for approximately 30% of all nosocomial blood stream infections. The majority of these concern catheter-related sepsis. Other important infections due to CNS include central nervous system shunt infections, endophthalmitis, surgical site infections, peritonitis in patients with continuous ambulatory peritoneal dialysis and foreign body infections. CNS are rarely associated with mastitis in humans. Staphylococcus lugdunensis is more pathogenic than other CNS as it expresses several potential virulence factors. The distinction between clinically significant, pathogenic and contaminating isolates is a major problem. Several studies show clonal intra and inter hospital spread of Staphylococcus epidermidis strains which suggests that infection control measures may be necessary for multiresistant CNS isolates as for methicillin resistant Staphylococcus aureus. As a result of medical progress, mainly due to the use of invasive and indwelling medical devices, CNS are now a major cause of nosocomial and health-care related infections.
                Bookmark

                Author and article information

                Journal
                BMC Infect Dis
                BMC Infect. Dis
                BMC Infectious Diseases
                BioMed Central
                1471-2334
                2013
                25 May 2013
                : 13
                : 242
                Affiliations
                [1 ]Department of Critical Care Medicine, Affiliated Provincial Hospital of Anhui Medical University, Hefei, China
                [2 ]Department of Laboratory, Affiliated Provincial Hospital of Anhui Medical University, No. 17, Lujiang Road, Hefei, 230001, China
                Article
                1471-2334-13-242
                10.1186/1471-2334-13-242
                3671247
                23705749
                6257b37f-0b65-438e-8f60-25469ced6fea
                Copyright ©2013 Zhou et al.; licensee BioMed Central Ltd.

                This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

                History
                : 27 March 2012
                : 20 May 2013
                Categories
                Research Article

                Infectious disease & Microbiology
                catheter-associated blood stream infections,s. epidermidis,slime,icaa/d,scanning electron microscopy

                Comments

                Comment on this article