Hospital pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) are feared worldwide and stand as the cause of about 100,000 infections annually in German hospitals. When the germ triggers blood poisoning or pneumonia in weakened patients, many of these infections end fatally. Until now, the hands of hospital staff were found to be the largest source of transmission of these bacteria. In some hospitals therefore it has already been decided to dispense with greeting and saying goodbye to patients with a handshake. Yet it’s not only the hands of the doctor which come into contact with the patient during every examination, the stethoscope is also nearly ever present. Doctors in Geneva have as part of a study of 83 patients now come to the conclusion: “The stethoscope is the extended hand of the physician and should be disinfected after each patient contact”.
Handshake, palpation, auscultation, palpation, handshake
The researchers had 83 patients examined under supervision at the Geneva University Hospital using sterile stethoscopes while always following the one same pattern. First, the participating doctors had to disinfect their hands thoroughly and welcome their patients with a handshake. Then they touched the A. radialis as well as the cervical and supraclavicular lymph node of their patient. After listening to the heart and lungs, the doctors examined the organs in the abdomen by tapping and scanning the body surface and the lower extremities of the patient. Then they said goodbye to their patients with a handshake.
Total bacterial cell count and MRSA
This procedure was carried out by two different groups: one group of doctors wearing sterile gloves, whose imprints provided information on the total number of bacteria; the second group worked with disinfected bare hands. The Geneva researchers examined the traces from the doctors’ handshakes for MRSA contamination after hand traces of the doctors taken before the examination served as an MRSA negative control. On average, the patients had last showered or been washed ten hours prior to the examination. After each standardised examination of a patient, the study doctors took from each treating physician six contact samples: from the stethoscope diaphragm and the tubing of the stethoscope, from the fingertips, back of the hand, the pads of the thumb and the little finger. Using a standard culture medium the scientists had all colony forming units (CFU) grow out from the 489 samples collected in this way.
Fingertips and stethoscope diaphragm carrying the most
The result was hardly surprising and left no questions unanswered: The previously sterile gloves were after only one examination downright saturated with microorganisms. From the fingertips, the study doctors were able to show on average 467 CFU. Thumb and small finger pads were with figures of 37 and 34 CFU significantly less loaded; the lowest CFU, 8, occurred in samples from the back of the hand. With this data, the researchers see confirmation of the need for strict hygiene regulations that require regular hand disinfection. The total microbial load of the stethoscope diaphragm matched the contamination level of the fingertips and was with an average of 89 CFU even higher than the germ load of the rest of the hand. Such results were derived from the doctors who had conducted their investigation with bare but disinfected hands as well. In this group, the investigators cultured the methicillin resistant Staphylococcus aureus onto a selective medium. Again here, the fingertips of doctors were, with an average of twelve CFU, the most contaminated; the diaphragm of the stethoscope followed with seven CFU in second place.
Disinfecting the stethoscope too, but how?
The results of this small study seem clear: To avoid infection with MRSA, disinfection of the hands is obviously not enough. The study physicians therefore urge that the stethoscope also be involved in the disinfection routine as are the hands. However, their study also has some weaknesses: it was conducted in only one hospital involving relatively few doctors and patients. Every second patient apparently carried the dangerous germ MRSA on his or her skin, with regard to which the doctors in the study paid no attention to the source of bacterial contamination in the study. What’s more, regarding the matter of contamination of practising doctors’ stethoscopes there is no conclusion that can be made on the basis of this study data. Even those who are now willing to disinfect their stethoscopes after every examination have at the moment no reliable data at hand. How this procedure could safely and effectively be carried out is something yet to be investigated.