AZ Sint Lucas Brugge
In AZ Sint-Lucas Bruges they currently use the crossmatch method to determine if the patient has irregular antibodies before a blood transfusion is performed. This method is very labor-intensive and causes stress to the laboratory technicians on busy moments.
The goal of this bachelor’s thesis is to validate the type and screen method in order to replace the crossmatch method, which is possible according to the American Association of Blood Banks (AABB).
However, in order to implement this method in the daily routine of the hospital, the safety needs to be evaluated.
The validation of this method is performed over a period of one month and three weeks. First was checked if the patient was suitable for type and screen. If the patient was not suitable for type and screen, the procedure of the crossmatch method was followed. If the patient was suitable, both the crossmatch and a screening for irregular antibodies were performed and the results were compared.
It can be concluded that the type and screen method is a safer method than the crossmatch method: irregular antibody screening was positive when the crossmatch was positive and five more cases of irregular antibodies were detected.
The implementation of this method can reduce the crossmatches by 62, 05 % in the current setting, which can relieve the workload on the laboratory technicians.
Although type and screen is more expensive than the crossmatch method, there are more advantages than disadvantages and therefore the hospital will implement this method in its daily routine.
In AZ Saint-Lucas Bruges, there is a preoperative screening for Staphylococcus aureus to prevent postoperative wound infections. This screening is carried out on all the dialysis patients and orthopedic patients who will have a prostheses. Also the patients of the breast clinic are screened.
They take a nose and throat sample with a TSB salt wiper. Because of the high salt level this is a selective medium for Staphylococcus aureus.
A comparison was made between the CNA-blood agar and the brilliance staph 24 side of the new brilliance staph 24/brilliance MRSA 2 biplate. This is a selective medium for the isolation of Coagulase positive Staphylococci within 24 hours. The CNA-blood agar has a sensitivity of 88.89 % but low specificity and positive predictive value. The biplate has a sensitivity of 100 % and high specificity and positive predictive value which makes the biplate a better screening method for Staphylococcus aureus.
The identification of the colonies is carried out with the MaldiTof. If it is a Staphylococcus aureus an antimicrobial susceptibility testing is performed to check the resistance and sensitivities for the decolonization schedule.
Preventing the occurrence of Carbapenemase-producing Enterobacteria (CPE) is still a major concern for public health in the world, because of the few remaining options for therapeutically treating infected patients. The rapid spread of CPE leads to nosocomial outbreaks and endemic situations in several European countries and all over the world. Therefore a fast detection and confirmation technique, with an influence on optimal hospital hygiene, is needed.
At A.Z. Sint-Lucas the detection of CPE carriage takes four days using the current method. The first day a wiper, taken from the patient's rectum, is submerged in McConkey broth. It's a selective medium that stimulates the grow of Enterobactericeae. After an overnight incubation at 37 °C, a drop from the McConkey broth is grafted onto a Brilliance CRE medium. After a second overnight incubation at 37 °C the plate is read. The CRE medium is selective, as a certain concentration of a carbapenem antibiotics mixture is added to the medium along with chromogenic substrates, which makes it possible to distinguish between CPE and non-CPE germs. When suspicious CPE stems are present, the E. coli will colour pale pink and KESC (Klebsiella, Enterobacter, Serratia and Citrobacter) will colour dark blue. To confirm the nature of the germ, it is identified through MaldiTOF. Antimicrobial susceptibility testing is performed on Microscan. Where there is a suspicion of CPE, the synergietest and E-test temocilline will be performed. The result will take 4 days. During this traineeship I was asked to examine several rapid testing methods, such as KPC plus OXA-48 K-Set and RAPIDEC® CARBA NP, to determine which are reliable and which can be used in the future to confirm CPE suspected isolates.
There were 35 suspected routine samples and 38 frozen suspected samples examined during the traineeship at A.Z. sint-Lucas, A.Z. Sint-Jan and A.Z. Alma (Eeklo). Sensitivity and specificity were only calculated from the frozen samples, because only one positive sample was detected in the routine samples. Sensitivity and specificity are two valuable standards by which a rapid test is evaluated. During this research traineeship it was apparent that both the current method and the new rapid test score highly on sensitivity and specificity. The rapid tests KPC/OXA-48 K-Set score the highest on sensitivity and specificity, but are not able to detect all carbapenemasen, which is a hugh disadvantage in the confirmation of CPE.
After putting side by side all results, the current method remains the best method to detect all kinds of suspect carbapenemase germs. The main disadvantage remains the longer delay to get results. In pursuit of patient care, which asks for a quick detection technique, RAPIDEC® CARBA NP offers the best progress for optimum hospital hygiene. When detecting a suspicous germ for CPE the best option is to use the RAPIDEC® CARBA NP test and get a reliable, both specific and sensitive, result. When the test strip gives a positive result, the current method is started for confirmation. By using both, the lower specificity of RAPIDEC® CARBA NP and the lower sensitivity of the current method are avoided. The two results combined give a reliable result.
St Lucaslaan 29