A Morphological Study of Bacterial Colonisation of Intravenous Cannulae

Abstract

SUMMARY. In an investigation of bacterial colonisation of intravascular cannulae, 16 peripheral venous cannulae of the Venflon variety and 24 chronic haemodialysis cannulae were studied after removal from patients. Studies of colonisation included semi-quantitative microbiological culture and scanning electronmicrographic (SEM) observations. The microbiological findings indicated colonisation of the intravascular portion of the catheter in 4 of 16 Venflon cannulae and 18 of 26 haemodialysis cannulae, largely with skin commensal organisms. The results of the SEM studies were in broad agreement with the microbiological observations. Surface defects on the cannulae were shown to be associated with microbial colonisation which occurred either as isolated colonies or in association with a cellular fibrinous matrix. These observations are illustrated and discussed.

In vitro quantitative model of catheter infection during simulated parenteral nutrition

“…especially the low infecting load of bacteria and the flow of the nutrient solution per catheter, probably account for these discrepancies. On the other hand, although the catheters were washed with fresh blood before inoculation, no fibrinous matrix was seen, unlike the results with clinically infected inserts (7,21,24).…”

The effect of antibiotics on bacterial colonisation of vascular cannulae in a novel in-vitro model

“…However, these models have not incorporated bacterial growth kinetics nor have they differentiated between bacterial colonisation of the internal and external cannula surfaces, which can occur in uivo (Cheesbrough et al, 1985). The design of the present model allowed the colonisation of bacteria, in predetermined phases of growth, on both cannula surfaces to be studied.…”

“…The internal and external surfaces of some of the cannulae were also examined by scanning electronmicroscopy (SEM) before and after washing to determine bacterial colonisation. To facilitate SEM examination of the internal surfaces, the cannulae were cut longitudinally as previously described (Cheesbrough et al, 1985). The numbers of bacteria present on 1-cm lengths of both surfaces of the cannulae were then determined directly.…”

Bacterial Uropathogens, Antimicrobial Susceptibility Profile and Associated Factors among Pediatric Patients in Bahir Dar, Northwest Ethiopia

“…Urine sample collection and bacteriological culture : The guardians or patients were instructed how to collect a clean-catch midstream urine specimen. Accordingly, about 5–10 ml urine specimen was collected from each participant in a sterile screw-capped, widemouth container and labeled with the unique sample number, date and time of collection ( 18 , 19 ). Using a cold box, all samples were transported to Bahir Dar University, College of Medicine and Health Science microbiology laboratory for bacteriological analysis.…”

“…The Gram-negative bacteria were identified by indole and H 2 S production in lysine iron agar (LIA), citrate utilization, urease test, motility test, and oxides and carbohydrate utilization tests. The Gram-positive bacteria were identified using catalase, coagulase and bilesculin test ( 18 , 19 ).…”