Today Staphylococcus epidermidis has been recognized as the etiological agent of infectious diseases such as endocarditis, sepsis and meningitis that mainly come out in compromised hosts because of the breaching of the mechanical barrier (cardiosurgical, neurosurgical patients and central venous catheter carriers). Other "non-epidermidis coagulase negative Staphylococci" are more and more frequently isolated from patients at high risk of infection. Faced with these isolations, it is difficult for the clinician and the microbiologist to give these microorganisms their effective pathogenic role. The Authors present a case list of seriously compromised patients in whom non-epidermidis coagulase negative Staphylococci were repeatedly isolated: hemato-oncological patients: the Authors mark out 6 cases of sepsis that is, likely, to be linked to a central venous catheter. The isolated microorganisms were: S. warneri (3 cases); S. haemolyticus (1 case); S. hominis (1 case); S. xylosus (1 case); neurosurgical patients: in whom 3 cases of cerebro-spinal fluid infection were observed; 3 patients carried a ventriculo-peritoneal derivation; 1 patient carried an Ommaya's device. The etiological agents were S. haemolyticus in 2 cases, S. capitis in 1 case. The Authors point out the multiresistance of some strains (S. haemolyticus) and the oxacillin-methicillin resistance phenomenon. They also underline the need for a specific identification of coagulase-negative Staphylococci and the importance of a strict collaboration between clinicians and microbiologists in order to get a correct interpretation of the role played by these microorganisms in infectious diseases of the compromised host.

Adolescent↗

PubMedDate not supplied

[The influence of click polarity and stimulation rate on the auditory evoked response in relation to age].

In order to study the changes which occur in phase of the click stimulus and its relation to the stimulus repetition rate on the auditory brainstem response (ABR) as a function of age, the Authors recorded the ABR from the scalp's surface of 10 newborns and 40 infants, 3 months, 6 months, 1 year and 3 years old as well as from 10 normal adults. The stimulus was a square wave of 0.1 msec duration and 90 dBHL level. The stimulus equipment was calibrated twice under visual inspection to ensure that the C and R clicks resulted in an initial membrane deflection toward and from the ear drum respectively. No significant differences could be found for the latencies and amplitude in the C-R comparison. However, the mean values of the complete group of test subjects showed most intraindividual stability for the conventional click stimulation. The latency of the ABR with excitation of the cochlea seemed to be mainly determined by the internal oscillation sequence in the cochlea and not by the stimulus polarity. The amplitudes and latencies of the ABR components tend to decrease when the stimulus rate increases and the age decreases. The importance of the stimulus characteristics is discussed and some suggestions for clinical use of ABR are made.

Acoustic Stimulation↗