Microbiological Analysis of Hemodialysis Water at the University Teaching Hospital of Yaounde, Cameroon

Abstract

Rigorous control of the microbiological quality of water in hemodialysis services is important because the immune system of patients with chronic renal failure is weakened. The objective of this study was to determine the microbiological quality of water for hemodialysis in the hemodialysis department of the University Teaching Hospital of Yaoundé in order to improve the disinfection strategy. Twelve water samples were collected each month at different sites of the hemodialysis circuits A (inlet of filters), B (Outlet of filters / inlet of Reverse Osmosis (RO) device) and C (outlet of the RO device / close to the generator) between July and October 2015 to be analyzed. The bacteria were isolated after filtration of 100 ml of water at each site through nitrocellulose membrane with 0.45 µm microporosity deposited on the surface of the Tryptone Glucose Extract Agar (TGEA) and then incubated at room temperature (20 to 22°C) for 7 days. After transplanting to different environments, pure bacterial isolates were identified by their cultural characters and marketed biochemical galleries. The colony count was well above the required international standards (˃100 CFU / ml), for the hemodialysis water with a percentage of 83.3% (10/12) of non-compliance. Among the bacteria identified, nine (09) were Gram-negative bacilli including Pasteurella haemolytica, Pseudomonas fluorescens, Pseudomonas paucimobilis, Aeromonas salmonicida and Klebsiella pneumoniae subsp ozaenae, three (03) Gram-positive bacilli all Bacillus sp and six (06) Gram-positive cocci all of coagulase-negative staphylococci. The most frequently isolated bacterial genera were Pseudomonas (30.4%), Staphylococcus (26.1%), Aeromonas (13%), Bacillus (13%), Klebsiella (13%) and Pasteurella (4.3%). In this study, the high bacteriological contamination of the hemodialysis water with the detection of a variety of bacteria shows that the disinfection procedure of the distribution loop is not efficient and cannot prevent the development of a biofilm. A higher frequency of disinfection (almost every week), an increase of the concentration and time of contact of the chlorine disinfection product or the use of peracetic acid and a regular monitoring can contribute to improve the quality of the hemodialysis water at the CHUY to ensure a better quality of life for patients undergoing this treatment.