Bacteriological water quality and biofilm formation in the treatment system of the hemodialysis unit in Tlemcen, Algeria.

OBJECTIVE: To evaluate and compare the microbiological quality of osmosis water at the distribution loop, at the dialysis generator inlet and to study the prevalence of biofilm in the tubing. METHODS: Microbiological analysis of 20 water loop samples, 10 water samples were taken at the machine entry and 10 pipe segments from tubing connecting the machines to the loop was done. RESULTS: The bacterial enumeration results of the loop water vary from 90 to 150 CFU/mL, while the average number of bacteria at the entry of the machines was 182 CFU/mL. The counts of the adhered bacteria in the tubing were worrying with rates ranging from 4.30 to 6.74 Log CFU/ cm2 . Fifty percentage of the strains isolated were Bacillus, followed by Enterobacter cloacae 23.52%, Staphylococcus, and others such as Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumanii. More than half of the tubing strains were highly formative of biofilm, 13 strains with medium capacity and 10 were weakly. CONCLUSION: This study indicates bacterial water contamination. The formation of a biofilm will certainly harm the effectiveness of the various disinfection methods in this unit. Water quality is influenced not only by the high rate of bacterial colonization, but also differences in standards for dialysis water.

Biocide tolerance and antibiotic resistance of Enterobacter spp. isolated from an Algerian hospital environment.

OBJECTIVES: In this study, 77 Enterobacter spp. isolates from a collection of 175 Gram-negative bacilli isolated from Tlemcen University Hospital Center (North-West of Algeria) were tested for antibiotic resistance, biocide tolerance and genetic determinants of antimicrobial resistance. METHODS: The isolates were identified by 16S rDNA gene sequencing. Biocide tolerance was determined by broth microdilution, and antibiotic resistance was determined by disk diffusion. Genetic determinants of resistance were studied by PCR amplification using suitable primers. RESULTS: The most common Enterobacter species was Enterobacter cloacae (58.4%), followed by Enterobacter hormaechei (24.7%). The most common antibiotic resistance was to ticarcillin either alone or in combination with clavulanic acid (70.1%), followed by cefepime (68.8%), cefotaxime (63.6%), ceftazidime (54.5%) and gentamicin (54.5%). Tobramycin was active against 87.0% of the isolates. Levels of biocide tolerance were high for hexachlorophene and to a lesser extent for benzalkonium chloride. The extended-spectrum ß-lactamase genes blaTEM and blaCTX-M were detected in 44.2% and 36.4% of isolates, respectively. Other antimicrobial resistance genes (ARGs) frequently detected were aac(6')-Ib (57.1%) and sul2 (50.6%). Multidrug-resistant isolates carrying several ARGs were common. Significant positive correlations were detected for efflux pump genes with ARGs and also between ARGs. CONCLUSION: The results of this study reveal thatEnterobacter spp. isolates from hospital settings are both resistant to clinically-used antibiotics and tolerant to biocides. Biocide tolerance could be an advantage for antibiotic-resistant strains in hospitals.