Polyclonal coagulase-negative staphylococcal catheter-related bacteremia documented by molecular identification and typing

Abstract

Coagulase-negative staphylococci (CNS) form part of the skin flora and commonly cause nosocomial bloodstream and catheter-related infections [l]. The increasing use of intravascular catheters and the high number of immunocompromised patients contribute to the importance of CNS as a cause of catheter-related infection. It is commonly assumed that catheter-related bloodstream infection arises from multiplication of a single infecting clone of CNS, whereas blood-culture contamination by skin flora is polyclonal, reflecting the diversity of CNS clones colonizing the skin [2]. However, there are recent reports of polyclonal endocarditis with multiple species or strains of CNS [3,4]. Different strains of CNS may exhibit the same morphology and since identification tests are usually made from a single colony, the true extent of infection remains to be investigated by identification and typing of different isolates from the same samples. Molecular fingerprinting methods can be used to investigate whether blood-culture isolates of CNS represent bacteremia or contamination. We describe a case of catheter-related bacteremia with polyclonal infection by Staphylococcns epidermidis and Staphylococcus hominis documented by molecular identification based on tRNA gene spacer polymorphism [5] and genotyping based on IS256 spacer polymorphism 161.A 58-year-old women suffering from a common acute lymphocytic leukemia diagnosed 6 months previously was receiving chemotherapy treatment through a totally implanted central venous catheter. This patient had neutropenia (total leukocytes 700/p,L, with 89% neutrophils) and developed fever (39.5"C) complicated by septic shock and hypotension (blood pressure: 8 mmHg systolic and 4 mmHg diastolic), which led to her admittance to the intensive care unit. Blood tests showed a CRP level of 26 mg/mL, and a fibrinogen level of 902 mg/mL. On the same day, two quantitative comparative blood samples were taken by reflux from the catheter and from a peripheral vein. As described previously [7], 1.

Polyclonal Staphylococcal Endocarditis Caused by Genetic Variability

“…The results of the in vivo experiments prove the possibility of genetic variability in vivo in the context of a foreign body-associated infection. This report is therefore different from the other reports in which a coinfection with multiple unrelated clones was proposed [9,10].…”

“…colonizing the foreign bodies [9,10]. Another investigator suggested that phenotypic and genotypic variation among Staphylococcus epidermidis strains that infected joint prostheses may have resulted from changes that occurred in situ during the infection process [11].…”

“…The total genome DNA of 7 different strains (A-G) was cut with 10 U of SmaI (lanes[1][2][3][4][5][6][7] and SstII (lanes[9][10][11][12][13][14][15] and restriction fragments were separated on a clamped homogeneous electric fields (CHEF) Mapper system (Bio-Rad, Hercules, CA). Lanes 1, 2, and 9, 10, Strains A and B, which belong to the aminoglycoside-susceptible type 1S, cut with SmaI and SstII, respectively.…”

Outbreaks associated to bloodstream infections with Staphylococcus aureus and coagulase-negative Staphylococcus spp in premature neonates in a university hospital from Brazil

“…However, reports of polymicrobial and polyclonal outbreaks are increasing (7,25) due to staphylococci and Gram negative bacilli (14,29).…”

Evaluation of Quantitative Antibiotic Susceptibility Testing by Vitek 2 as a Routine Method To Predict Strain Relatedness of Coagulase-Negative Staphylococci Isolated from Blood Cultures

“…Although this assumption is supported by various clinical and microbiologic studies (8,15), there might be rare exceptions, with classification of strains as identical being the result of repeated contamination and of distinct strains being the result of a polyclonal infection (7,19). In addition, CoNS colonies were selected from primary subcultures of positive blood cultures based on colony morphology and preliminary agar diffusion susceptibility results; agar plates were not searched systematically for the presence of different strain types as was performed in other studies (4,6).…”