Abstract
Selected coagulase-negative staphylococci from the blood of very-low-birth-weight infants in the Neonatal Intensive Care Unit at the Royal Women’s Hospital, Melbourne, collected over a 5-year period were examined. Isolates were classified as invasive or contaminants, speciated, typed by pulsed-field gel electrophoresis, and examined for biofilm genes (icaA, icaC, and icaD), adhesion genes (atlE, fbe), and the number of copies of IS256. Of the 24 isolates studied, there were 13 contaminants and 11 invasive isolates. The collection included 15 Staphylococcus epidermidis, eight Staphylococcus capitis, and one each of Staphylococcus warneri and Staphylococcus haemolyticus. Two small clusters of S. epidermidis that belonged to the same molecular type were identified. All S. capitis isolates belonged to the same molecular type or subtype, suggesting that a particular clone was circulating in the unit. There was no significant difference in the species found, the presence of icaA, icaC, icaD, atlE, or fbe, or the number of copies of IS256 between invasive isolates and contaminants. A series of nasal isolates from nonhospitalized adults differed from hospital isolates in the absence of IS256 and the low prevalence of icaC. There was no evidence of IS256-mediated insertion into ica genes as a mechanism of phase variation. These findings suggest that contaminants and invasive isolates derived from the same pool of hospital strains capable of causing sepsis in compromised hosts and that other mechanisms of phase variation exist, apart from IS256 insertion into ica genes.
Similar content being viewed by others
References
Stoll BJ, Hansen N, Fanaroff AA, Wright LL, Carlo WA, Ehrenkranz RA, Lemons JA, Donovan EF, Stark AR, Tyson JE, Oh W, Bauer CR, Korones SB, Shankaran S, Laptook SAR, Stevenson DK, Papile LA, Poole WK (2002) Late-onset sepsis in very low birth weight neonates: the experience of the NICHD Neonatal Research Network. Pediatrics 110:285–291
Kaufman D, Fairchild KD (2004) Clinical microbiology of bacterial and fungal sepsis in very low birth weight babies. Clin Microbiol Rev 17:638–680
Bialkowska-Hobrzanska H, Jaskot D, Hammerberg O (1993) Molecular characterization of the coagulase-negative staphylococcal surface flora of premature neonates. J Gen Microbiol 139:2939–2944
Björkqvist MB, Söderquist O, Törnqvist E, Sjöberg L, Fredlund H, Kühn I, Colque-Navarro P, Schollin J (2002) Phenotypic and genotypic characterisation of blood isolates of coagulase-negative staphylococci in the newborn. APMIS 110:332–339
Burnie JP, Naderi-Nasab M, Loudon KW, Matthew RC (1997) An epidemiological study of blood culture isolates of coagulase-negative staphylococci demonstrating hospital-acquired infection. J Clin Microbiol 35:1746–1750
Huebner JG, Pier B, Maslow JN, Muller, Shiro EH, Parent M, Kropec A, Arbei RD, Goldmann DA (1994) Endemic nosocomial transmission of Staphylococcus epidermidis bacteremia isolates in a neonatal intensive care unit over 10 years. J Infect Dis 169:526–531
Low DE, Schmidt BK, Kirpalani HM, Moodie R, Kreiswirth B, Matlow A, Ford-Jones EL (1992) An endemic strain of Staphylococcus haemolyticus colonizing and causing bacteremia in neonatal intensive care unit patients. Pediatrics 89:696–700
Raimundo O, Heussler H, Bruhn JB, Suntrarachun S, Kelly N, Deighton MA, Garland SM (2002) Molecular epidemiology of coagulase-negative staphylococcal bacteraemia in a newborn intensive care unit. J Hosp Infect 51:33–42
Vermont CL, Hartwig NG, Fleer A, de Man P, Verbrugh H, van den Anker J, de Groot R, van Belkum A (1998) Persistence of clones of coagulase-negative staphylococci among premature neonates in neonatal intensive care units: two-center study of bacterial genotyping and patient risk factors. J Clin Microbiol 36:2485–2490
Villari P, Sarnataro C, Iacuzio L (2000) Molecular epidemiology of Staphylococcus epidermidis in a neonatal intensive care unit over a three-year period. J Clin Microbiol 38:1740–1746
Vuong C, Otto M (2002) Staphylococcus epidermidis infections. Microbes Infect 4:481–489
Vuong C, Kocianova S, Voyich JM, Yao Y, Fischer ER, DeLeo FR, Otto M (2004) A crucial role for exopolysaccharide modification in bacterial biofilm formation, immune evasion and virulence. J Biol Chem 279:54881–54886
de Silva GD, Kantzanou M, Justice A, Massey RC, Wilkinson AR, Day NP, Peacock SJ (2002) The ica operon and biofilm production in coagulase-negative staphylococci associated with carriage and disease in a neonatal intensive care unit. J Clin Microbiol 40:382–388
Cho S-H, Naber K, Hacker J, Ziebuhr W (2002) Detection of the icaADBC gene cluster and biofilm formation in Staphylococcus epidermidis isolates from catheter-related urinary tract infections. Int J Antimicrob Agents 19:570–575
Ziebuhr W, Krimmer V, Rachid S, Lössner I, Götz F, Hacker J (1999) A novel mechanism of phase variation of virulence in Staphylococcus epidermidis: evidence for control of the polysaccharide intercellular adhesin synthesis by alternating insertion and excision of the insertion sequence element IS256. Mol Microbiol 32:345–356
Kozitskaya S, Cho S-H, Dietrich K, Marre R, Naber K, Ziebuhr W (2004) The bacterial insertion sequence element IS256 occurs preferentially in nosocomial Staphylococcus epidermidis isolates: association with biofilm formation and resistance to aminoglycosides. Infect Immun 72:1210–1215
Rohde H, Knobloch JH, Horstkotte MA, Mack D (2001) Correlation of biofilm expression types of Staphylococcus epidermidis with polysaccharide intercellular adhesin synthesis: evidence for involvement of icaADBC genotype-independent factors. Med Microbiol Immunol 190:105–112
National Committee for Clinical Laboratory Standards (2003) Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically. Approved standard M7-A6. NCCLS, Wayne, Pennsylvania
Smith CL, Cantor CR (1987) Purification, specific fragmentation, and separation of large DNA molecules. Methods Enzymol 155:449–467
Tenover FC, Arbeit RD, Goering RV, Mickelsen PA, Murray BE, Persing DH, Swaminathan B (1995) Interpreting chromosomal DNA restriction patterns produced by pulsed-field gel electrophoresis: criteria for bacterial strain typing. J Clin Microbiol 33:2233–2239
Unal S, Hoskins J, Flokowitsch JE, Wu CY, Preston DA, Skatrud PL (1992) Detection of methicillin-resistant staphylococci by using the polymerase chain reaction. J Clin Microbiol 30:1685–1691
Handke LD, Conlon KM, Slater SR, Elbaruni S, Fitzpatrick F, Humphreys H, Giles WP, Rupp ME, Fey PD, O’Gara JP (2004) Genetic and phenotypic analysis of biofilm phenotypic variation in multiple Staphylococcus epidermidis isolates. J Med Microbiol 53:367–374
Freeman D, Falkiner JFR, Keane CT (1989) New method for detecting slime production by coagulase negative staphylococci. J Clin Pathol 42:872–874
Heilmann C, Götz F (1998) Further characterization of Staphylococcus epidermidis transposon mutants deficient in primary attachment or intercellular adhesion. Zentralbl Bakteriol 287:69–83
Deighton MA, Capstick, Domalewski JE, van Nguyen T (2001) Methods for studying biofilms produced by Staphylococcus epidermidis. Methods Enzymol 336:177–195
Knobloch JK, Horstkotte MA, Rohde H, Kaulfers PM, Mack D (2002) Alcoholic ingredients in skin disinfectants increase biofilm expression of Staphylococcus epidermidis. J Antimicrob Chemother 49:683–687
Van Der Zwet WC, Debets-Ossenkopp YJ, Reinders E, Kapi M, Savelkoul PH, Van Elburg RM, Hiramatsu K, Vandenbroucke-Grauls CM (2002) Nosocomial spread of a Staphylococcus capitis strain with heteroresistance to vancomycin in a neonatal intensive care unit. J Clin Microbiol 40:2520–2525
Wang S-M, Liu C-C, Tseng H-W, Yang Y-J, Lin C-H, Huang A-Y, Wu Y-H (1999) Staphylococcus capitis bacteremia of very low birth weight premature infects at neonatal intensive care units: clinical significance and antimicrobial susceptibility. J Immunol Infect 32:26–32
Conlon KM, Humphreys H, O’Gara JP (2004). Inactivations of rsbU and sarA by IS256 represent novel mechanisms of biofilm phenotypic variation in Staphylococcus epidermidis. J Bacteriol 186:6208–6219
Klug D, Wallet F, Kacet S, Courcol RJ (2003) Involvement of adherence and adhesion Staphylococcus epidermidis genes in pacemaker lead-associated infections. J Clin Microbiol 41:3348–3350
Frebourg NB, Lefebvre S, Baert S, Lemeland JF (2000) PCR-based assay for discrimination between invasive and contaminating Staphylococcus epidermidis strains. J Clin Microbiol 38:877–880
Rohde H, Kalitzky M, Kröger N, Scherpe S, Horstkotte MA, Knobloch JKM, Zander AR, Mack D (2004) Detection of virulence-associated genes not useful for discriminating between invasive and commensal Staphylococcus epidermidis strains from a bone marrow transplant unit. J Clin Microbiol 42:5614–5619
Arciola CR, Campoccia D, Gamberini S, Rizzi S, Donati ME, Baldassarri L, Montanaro L (2004) Search for the insertion element IS256 within the ica locus of Staphylococcus epidermidis clinical isolates collected from biomaterial-associated infections. Biomaterials 25:4117–4125
Nilsson M, Frykberg L, Flock JI, Pei L, Lindberg M, Guss B (1998) A fibrinogen-binding protein of Staphylococcus epidermidis. Infect Immun 66:2666–2673
Acknowledgement
This work was partly supported by a grant from the Faculty of Life Sciences, RMIT University, Bundoora, Victoria, Australia.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Bradford, R., Abdul Manan, R., Daley, A.J. et al. Coagulase-negative staphylococci in very-low-birth-weight infants: inability of genetic markers to distinguish invasive strains from blood culture contaminants. Eur J Clin Microbiol Infect Dis 25, 283–290 (2006). https://doi.org/10.1007/s10096-006-0130-2
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10096-006-0130-2