Bacterial DNA in the diagnosis of spontaneous bacterial peritonitis

BACKGROUND

Despite inoculation into blood culture bottles, ascitic fluid culture is negative in 50% of cases of spontaneous bacterial peritonitis (SBP).

AIM

To determine whether 16S rDNA gene detection by real-time polymerase chain reaction (PCR) and sequencing increases the efficacy of culture in microbiological diagnosis of spontaneous bacterial peritonitis.

METHODS

We prospectively included 55 consecutive spontaneous bacterial peritonitis episodes in cirrhotic patients, 20 cirrhotic patients with sterile ascites and 27 patients with neoplasic ascites. Ascitic fluid was inoculated into blood culture bottles at the bedside and tested for bacterial DNA by real-time PCR and sequencing of 16S rDNA gene.

RESULTS

Bacterial DNA was detected in 23/25 (92%) culture-positive SBP, 16/30 (53%) culture-negative SBP (P = 0.002 with respect to culture-positive SBP), 12/20 (60%) sterile ascites (P = 0.01 with respect to culture-positive SBP) and 0/27 neoplasic ascites (P < 0.001 with respect to other groups). Sequencing identified to genus or species level 12 culture-positive SBP, six culture-negative SBP and six sterile ascites. In the remaining cases with positive PCR, sequencing did not yield a definitive bacterial identification.

CONCLUSIONS

Bacterial DNA was not detected in almost half the culture-negative spontaneous bacterial peritonitis episodes. Methodology used in the present study did not always allow identification of amplified bacterial DNA.

The role of a computed tomography-based image registered navigation system for natural orifice transluminal endoscopic surgery: a comparative study in a porcine model

BACKGROUND AND STUDY AIMS

Most natural orifice transluminal endoscopic surgery (NOTES) procedures have been performed in animal models through the anterior stomach wall, but this approach does not provide efficient access to all anatomic areas of interest. Moreover, injury of the adjacent structures has been reported when using a blind access. The aim of the current study was to assess the utility of a CT-based (CT: computed tomography) image registered navigation system in identifying safe gastrointestinal access sites for NOTES and identifying intraperitoneal structures.

METHODS

A total of 30 access procedures were performed in 30 pigs: anterior gastric wall (n = 10), posterior gastric wall (n = 10), and anterior rectal wall (n = 10). Of these, 15 procedures used image registered guidance (IR-NOTES) and 15 procedures used a blind access (NOTES only). Timed abdominal exploration was performed with identification of 11 organs. The location of the endoscopic tip was tracked using an electromagnetic tracking system and was recorded for each case. Necropsy was performed immediately after the procedure. The primary outcome was the rate of complications; secondary outcome variables were number of organs identified and kinematic measurements.

RESULTS

A total of 30 animals weighting a mean (± SD) of 30.2 ± 6.8 kg were included in the study. The incision point was correctly placed in 11 out of 15 animals in each group (73.3 %). The mean peritoneoscopy time and the number of properly identified organs were equivalent in the two groups. There were eight minor complications (26.7 %), two (13.3 %) in the IR-NOTES group and six (40.0 %) in the NOTES only group ( P = n. s.). Characteristics of the endoscope tip path showed a statistically significant improvement in trajectory smoothness of motion for all organs in the IR-NOTES group.

CONCLUSION

The image registered system appears to be feasible in NOTES procedures and results from this study suggest that image registered guidance might be useful for supporting navigation with an increased smoothness of motion.

Toll-like receptor 4 D299G polymorphism and the incidence of infections in cirrhotic patients

BACKGROUND

Toll-like receptor (TLR) 4 genetic polymorphisms, mainly D299G, have been associated with increased predisposition to infection in several populations.

AIM

To retrospectively analyse the relationship between the presence of the TLR4 D299G polymorphism and the incidence of bacterial infections in cirrhotic patients.

METHODS

We included 111 consecutive cirrhotic patients hospitalized with ascites and we determined the presence of the TLR4 D299G polymorphism by PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) and its relationship with the incidence of previous bacterial infections.

RESULTS

Ten out of 111 (9%) cirrhotic patients presented with the TLR4 D299G polymorphism. The mean follow-up from first decompensation of cirrhosis until current admission was longer in D299G polymorphism patients than in wild-type patients (53.8 +/- 40.7 vs. 35.4 +/- 48.3 months, P = 0.03). D299G polymorphism patients showed a trend towards a higher incidence of history of previous infections (80% vs. 56.4%, P = 0.19), as well as a higher number of infections (2.8 +/- 2.3 vs. 1.0 +/- 1.3, P = 0.01) and bacteriaemias (0.4 +/- 1.0 vs. 0.04 +/- 0.2, P = 0.02) per patient than wild-type patients.

CONCLUSIONS

Toll-like receptor 4 D299G polymorphism could influence not only the predisposition to bacterial infections but also the evolution of the disease in cirrhotic patients. Further prospective studies in larger series of patients are warranted.