Identification of human-dependent routes of pathogen's transmission in a tertiary care hospital

What if an articular bone fragment drops on the floor in the course of osteosynthesis? An experimental study

OBJECTIVES

This study aimed to evaluate the effectiveness of a 1-min 10% povidone-iodine immersion in the decontamination of dropped osteochondral fragments.

MATERIALS AND METHODS

Forty-eight sets of sterile osteochondral bone fragments, each consisting of three samples, were prepared from removed femoral heads that would otherwise be discarded during different hip replacement surgeries. Immediately afterward, each set was dropped on the floor right behind the surgeon in another operating room in which fracture fixation operations were being performed. Samples were picked up with sterile gloves. A swab culture of the floor was taken. One of the three pieces was kept as the control group. The second one (saline group) was washed with saline and subsequently soaked in saline for 1 min. The last one (treatment group) was first immersed in a 10% povidone-iodine solution for 1 min, then rinsed with saline and soaked in saline for 1 min. The samples were cultured in nutrient media, and microorganisms were identified at the microbiology laboratory. The groups were compared in terms of positive culture rates.

RESULTS

The positive culture (contamination) rates were 100%, 58.3%, 39.6%, and 10.4% for the swab samples, control group, saline group, and treatment group respectively. The decontamination ratio in the treatment group was significantly more than both the control group (p<0.001) and the saline group (p=0.001). Handling only with saline did not significantly decontaminate compared to the control group (p=0.066).

CONCLUSION

Immersing the dropped osteochondral fragments in 10% povidone-iodine solution for 1 min and then rinsing with saline may provide statistically significant decontamination but cannot be accepted to be safe enough for clinical practice. Further studies are needed to find the optimal time needed for safe decontamination without compromising the viability of cartilage tissue.

High Prevalence and Varied Distribution of Antibiotic-Resistant Bacteria in the Rhizosphere and Rhizoplane of Citrus medica

The plant-associated bacteria, including that in the rhizosphere and rhizoplane, play important roles in human exposure to antibiotic-resistant bacteria (ARB). The rhizosphere and rhizoplane represent two distinct environments with different selective pressures for bacterial colonization. However, whether the difference in characteristics between the rhizosphere and rhizoplane can affect the abundance and antibiotic resistance profiles of ARB colonizing, the two environments remain largely unknown. In this study, we obtained 174 bacterial isolates from the rhizosphere (113 isolates) and rhizoplane (61 isolates) of Citrus medica trees grown in a park, where humans could easily and frequently contact the trees. A very high proportion of isolates exhibited resistance to several clinically important antibiotics, including β-lactam class antibiotics and polymyxin, with several known antibiotic-resistant opportunistic pathogens, such as Micrococcus luteus, being identified. The prevalence of ARB in the rhizoplane was higher than that in the rhizosphere. While the prevalence of polymyxin-resistant isolates was higher in the rhizoplane, the prevalence of amphenicol-resistant isolates was significantly higher in the rhizosphere. In summary, our findings suggest that the rhizosphere and rhizoplane are important media for the spread of ARB, and the different characteristics between the two environments can affect the distribution of ARB.