Predictive value of surveillance skin and hub cultures in central venous catheters sepsis

Central Venous Catheter Infection

“…This is not supported by the literature with studies showing a large proportion of cases of hub-related infection growing >15cfu on roll-plating (Fan et al 1988, Sitges-Serra et al 1988, Kristinsson et al 1989. Typically, Bozzetti (1991) demonstrated that contamination of the hub with high numbers of organisms was associated with a positive external surface in 50% of cases.…”

“…Flowers et al (1989), in ICU patients, found a positive predictive value of 12 tip colonisation of 45.5% with a positive hub culture and 60% with a positive site culture. Other authors have reported that a combination of both cultures provides the best sensitivity in diagnosing infection without removing the catheter: Fan et al (1988) found daily hub and twice weekly skin cultures gave a combined sensitivity for bacteraemia of 79.3%, with a positive predictive value of 44.2% and negative of 93.3%. With clinical signs of infection, Cerenado et al (1990) found combined skin and hub cultures gave a sensitivity, for a positive tip culture, of 97.1 %, with a positive predictive value of 34% and negative of 99.4%.…”

“…A low inoculum was used to simulate levels of contamination in vivo. Fan et al (1988) A viable count was chosen as a measure as only live organisms are capable of causing infection. The Miles and Misra technique (Miles and Misra 1938) of serial dilutions and drop counts was identified as the most accurate for organisms able to grow well on opaque media and enabled verification that colonies were of the original species inoculated with no contaminants.…”

“…There is also the possibility that the catheter tip may have been contaminated on removal and thus the discriminatory ability of the culture method is important. In addition, studies have demonstrated the presence of the same organism on both site and hub (Di Cicco et al 1989, Fan et al 1988, thus hub culture is required to exclude the intraluminal route.…”

Pathogenesis of infections related to intravascular catheterization

“…3) (107). However, investigators from Barcelona, Spain, have suggested that this figure omits an additional route of catheterrelated infection: contamination of the catheter hub (45,99,175). In one study of 135 subclavian catheters, 14 (70%) of 20 episodes of bacteremia were thought to have originated from a contaminated hub, with secondary colonization of the catheter tip (99).…”