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Molecular Characterization of Methicillin-Resistant Coagulase-Negative Staphylococci from a Neonatal Intensive Care Unit

  • Isabel Bogado (a1) (a2), Adriana Limansky (a1) (a2), Emma Sutich (a2), Patricia Marchiaro (a2), Marta Marzi (a2), Juan Putero (a3) and Alejandro Viale (a1) (a2)...



To evaluate clonal dissemination of methicillin-resistant coagulase-negative staphylococci (CNS).


Neonatal intensive care unit of a 180-bed, university-affiliated general hospital.


Neonates admitted to the neonatal intensive care unit between March 1999 and October 2000, from whom CNS were isolated as a unique pathogen. Patients from other wards from whom epidemiologically unrelated staphylococci strains were obtained served as control-patients.


Conventional methods were used for phenotypic characterization of CNS. Methicillin resistance was determined by mecA polymerase chain reaction (PCR) amplification. Genotypic characterization was done by random amplification of DNA with degenerated primers (RAPD) and repetitive element sequence-based PCR (rep-PCR).


Forty methicillin-resistant CNS isolates obtained from neonates were characterized as Staphylococcus epidermidis (33), S. hominis (5), S. warneri (1), and S. auricularis (1). Both RAPD and rep-PCR indicated the presence of 4 different clones among the 33 S. epidermidis isolates. In turn, the 4 randomly selected, epidemiologically unrelated methicillin-resistant CNS strains obtained from control-patients showed 3 new profiles by RAPD and 2 by rep-PCR, which differed from the corresponding patterns mentioned earlier. Persistence of S. hominis in a neonate could be assessed by both genotypic techniques.


The molecular characterization of the methicillin-resistant CNS studied indicated dissemination of one particular methicillin-resistant CNS clone among the neonates in the ward studied. Although RAPD showed a superior power to discriminate among methicillin-resistant CNS isolates, both RAPD and rep-PCR detected intraspecific and interspecific genomic diversity.


Corresponding author

Cátedra de Microbiología Clínica I, Facultad de Cs. Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531-2000 Rosario, República Argentina


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1.Einsenstein, BI, Schaechter, M. Biota microbiana normal. In: Editorial Médica Panamericana. Microbiología: Mecanismo de las Enfermedades Infecciosas, 2nd ed. Madrid, Spain: Panamericana; 1994:3646.
2.Kloos, W, Bannerman, T. Update on clinical significance of coagulase-neg-ative staphylococci. Clin Microbiol Rev 1994;1:117140.
3.Chambers, HF. Methicillin resistance in staphylococci: molecular and biochemical basis and clinical implications. Clin Microbiol Rev 1997; 10:781791.
4.Jarvis, WR, Martone, WJ. Predominant pathogens in hospital infections. J Antimicrob Chemother 1994;29(suppl A):1924.
5.Sechi, L, Pinna, A, Pusceddu, C, Fadda, G, Carta, F, Zanetti, S. Molecular characterization and antibiotic susceptibilities of ocular isolates of Staphylococcus epidermidis. J Clin Microbiol 1999;37:30313033.
6.Hebert, GA, Cooksey, RC, Clark, NC, Hill, BC, Jarvis, WR, Thornsberry, C. Biotyping coagulase-negative staphylococci. J Clin Microbiol 1988;26: 19501956.
7.Ferreiros, CM, Souto, MJ, Criado, MT, Suarez, P. Phage typing and phage induction in carrier and invasive Staphylococcus epidermidis isolates. J Hosp Infect 1991;18:293299.
8.Van der Mee, N, Mallet, S, Lolergue, J, Audurier, A. Typing of Staphylococcus epidermidis strains by random amplification of polymorphic DNA. FEMS Microbiol Lett 1995;128:3944.
9.Izard, N, Hachler, H, Grehn, M, Kayser, F. Ribotyping of coagulase-negative staphylococci with special emphasis on intraspecific typing of Staphylococcus epidermidis. J Clin Microbiol 1992;30:817823.
10.Van der Zee, A, Verbakel, H, van Zon, JC, et al. Molecular genotyping of Staphylococcus aureus strains: comparison of repetitive element sequence-based PCR with various typing methods and isolation of a novel epidemicity marker. J Clin Microbiol 1999;37:342349.
11.Limansky, A, Sutich, E, Guardati, MC, Toresani, I, Viale, A. Genomic diversity among Streptococcus agalactiae isolates detected by a degenerate oligonucleotide-primed amplification assay. J Infect Dis 1998;177:13081313.
12.Holt, J, Krieg, N, Sneath, P, Staley, J, Williams, S. Group 17 Gram positive cocci. In: Hensyl, WR, Forlifer, LE. Bergey's Manual of Determinative Bacteriology, 9th ed. Baltimore, MD: Williams & Wilkins; 1994:544551.
13.Kloss, WE Jr, Lambe, DW. Staphylococcus. In: Balows, A, Hausler, WJ, Herrmann, KL, et al., eds. Manual of Clinical Microbiology, 5th ed. Washington, DC: American Society for Microbiology; 1991:222237.
14.Isemberg, HD. Identification of commonly isolated aerobic gram-positive bacteria. In: Isemberg, HD, ed. Clinical Microbiology Procedures Handbook, vol. 1. Washington, DC: American Society for Microbiology; 1995:
15.Predari, S, Ligozzi, M, Fontana, R. Genotypic identification of methicillin resistant coagulase-negative staphylococci by polymerase chain reaction. Antimicrob Agents Chemother 1991;35:25682573.
16.Sambrook, J, Fritsh, EF, Maniatis, T. Molecular cloning. In: Ford, N, Nolan, C, Ferguson, M, eds. A Laboratory Manual, 2nd ed. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory Press; 1989.
17.Wu, S, de Lencastre, H, Tomasz, A. Genetic organization of the meek region in methicillin-susceptible and methicillin-resistant strains of Staphylococcus sciuri. J Bacteriol 1998;180:236242.
18.Ludwig, W, Kirchof, G, Hugbauer, N, et al. Complete 23S ribosomal RNA sequences of gram-positive bacteria with a low DNA G+C content. Systematic and Applied Microbiology 1992;15:487501.
19.Unal, S, Hoskins, J, Flokowitsch, JE, Wu, CYE, Preston, DA, Skatrud, PL. Detection of methicillin-resistant staphylococci by using the polymerase chain reaction. J Clin Microbiol 1992;30:16851691.
20.Hunter, PR. Reproducibility and indices of discriminatory power of microbial typing methods. J Clin Microbiol 1990;28:19031905.
21.Hunter, PR, Gaston, MA. Numerical index of the discriminatory ability of typing systems: an application of Simpson's index of diversity. J Clin Microbiol 1988;26:24652466.
22.Izard, N, Hachler, H, Grehn, M, Kayser, F. Ribotyping of coagulase-negative staphylococci with special emphasis on intraspecific typing of Staphylococcus epidermidis. J Clin Microbiol 1992;30:817823.
23.Sung, L, Ramotar, K, Samson, L, Toye, B. Bacteremia due to persistent strains of coagulase-negative staphylococci in a neonatal intensive care unit. Infect Control Hosp Epidemiol 1999;20:349351.
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Infection Control & Hospital Epidemiology
  • ISSN: 0899-823X
  • EISSN: 1559-6834
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