Effects of laparoscopic models on anaerobic bacterial growth with bacteroides fragilis in experimentally induced peritonitis

The Role of DNA Amplification and Cultural Growth in Complicated Acute Appendicitis

Bacterial growth of peritoneal fluid specimens obtained during surgical procedures for acute appendicitis may be useful to optimize further antibiotic therapy in complicated cases. DNA amplification represents a fast technique to detect microbial sequences. We aimed to compare the potential of DNA amplification versus traditional bacterial growth culture highlighting advantages and drawbacks in a surgical setting. Peritoneal fluid specimens were collected during surgery from 36 children who underwent appendectomy between May and December 2012. Real-time polymerase chain reaction (RT-PCR) and cultures were performed on each sample. RT-PCR showed an amplification of 16S in 18/36 samples, Escherichia coli (in 7 cases), Pseudomonas aeruginosa (3), Fusobacterium necrophorum (3), Adenovirus (2), E.coli (1), Klebsiella pneumoniae (1), Serratia marcescens/Enterobacter cloacae (1). Bacterial growth was instead observed only in four patients (3 E.coli and 1 P.aeruginosa and Bacteroides ovatus). Preoperative C-reactive protein and inflammation degree, the most reliable indicators of bacterial translocation, were elevated as expected. DNA amplification was a quick and useful method to detect pathogens and it was even more valuable in detecting aggressive pathogens such as anaerobes, difficult to preserve in biological cultures; its drawbacks were the lack of biological growths and of antibiograms. In our pilot study RT-PCR and cultures did not influence the way patients were treated.

Carbon dioxide pneumoperitoneum induces anti-inflammatory response and hepatic oxidative stress in young rats with bacterial peritonitis

PURPOSE

The aim of this study was to investigate the effects of carbon dioxide (CO(2)) pneumoperitoneum on the intra-abdominal spread of bacteria, the local and systemic cytokine expression, and oxidant/antioxidant status in young rats with bacterial peritonitis.

METHODS

Young Sprague-Dawley rats, aging 20-27 days and weighing around 50 g, were allocated to six groups of six to nine animals in each. Intra-abdominal infection model was developed by intraperitoneal injection with 1 cc of Escherichia coli (E. coli) (10(8) CFU/mL, ATCC25922 strain) via right lower abdominal wall. Carbon dioxide (CO(2)) pneumoperitoneum was applied to the rats via umbilical pit insufflation with 20 cc CO(2) for 30 min. All survived rats underwent laparotomy and were killed 24 h or 3 days later. Serum levels of CO(2) and CRP were measured. Left lower abdomen peritoneum, peritoneal fluid, mesenteric lymph node of terminal ileum, and liver were taken for bacterial culture. Liver and plasma levels of TNF-α, IL-1β, and IL-6 were examined for the level of local and systemic immunologic response. Oxidant/antioxidant status in liver and plasma were assessed by measuring malondialdehyde (MDA), and reduced to oxidized glutathione ratio (GSH/GSSG).

RESULTS

Carbon dioxide (CO(2)) pneumoperitoneum does not facilitate E. coli dissemination to other intra-abdominal organs in rats with localized E. coli peritonitis. Peritonitis rats that underwent abdominal CO(2) insufflation have insignificantly higher CRP or lower CO(2) levels. Plasma and liver TNF-α, IL-1β concentrations were not significantly different among the four groups, but plasma IL-6 was significantly increased in rats with E. coli peritonitis and CO(2) pneumoperitoneum that were killed 3 days later as compared with that of rats that were killed 24 h later. In rats with E. coli peritonitis, CO(2) pneumoperitoneum was significantly associated with decreased hepatic GSH/GSSG ratio. However, plasma and liver MDA levels were not altered after CO(2) pneumoperitoneum.

CONCLUSIONS

Carbon dioxide (CO(2)) pneumoperitoneum is not associated with E. coli dissemination in the presence of local intra-abdominal infection. CO(2) pneumoperitoneum elicited systemic anti-inflammatory response at a specific time period and decreased hepatic antioxidant status in young rats with E. coli peritonitis.

Early effects of laparotomy and laparoscopy on bacterial behavior and proinflammatory cytokines on bacterial peritonitis in rats I: Escherichia coli

PURPOSE

The aim of this study was to investigate in rats with peritonitis the effect of CO2 insufflation on behavior of bacteria, including antibiotic resistance, and the systemic and regional host response.

METHODS

Inbred weaned Wistar albino rats were used. Escherichia coli ATCC 25922 was used to induce peritonitis. Rats with peritonitis were allocated to 4 groups: group 1, control; group 2, laparotomy; group 3, laparoscopy; group 4, laparoscopy + laparotomy and were killed at the end of the second hour of peritonitis. Serum, peritoneal fluid, and intraabdominal organs were taken for microbiological (biochemical markers-urease, citrate, indole; virulence factors-biofilm, protease, gelatinase, adherence), systemic immunologic (interleukin 1 [IL-1]alpha, IL-1beta, tumor necrosis factor alpha, IL-6), and regional histopathologic evaluations. Isolated strains were tested against minimum inhibitory concentrations (MICs) and sub-MICs of amikacin and amoxicillin.

RESULTS

Regional inflammatory response was the highest in group 2 but the lowest in group 4. Systemic IL-1alpha level was significantly higher in group 2, and TNF-alpha level was higher in group 3. After the peritonitis process, Escherichia coli began to use citrate and urea in control groups (without antibiotic treatment). In groups 2 and 4, amoxicillin resistance developed.

CONCLUSIONS

In peritonitis, in all experimental groups, Escherichia coli used different metabolic pathways other than in normal atmospheric conditions. Amoxicillin resistance developed in open surgery groups. Further kinetic microbiological and immune response studies are needed concerning the early and late effects of CO2 insufflation on various strains of bacteria and mixed infections.

[Appendicitis: yes or no to laparoscopic approach?]

Whether or not there is a benefit to laparoscopy versus open surgery in the management of acute appendicitis remains a subject of controversy despite the publication of numerous randomized studies. Operative time is longer for the laparoscopic approach. The incidence of abdominal wall abscess is decreased for laparoscopy but the incidence of deep intra-abdominal abscess may be increased, especially in the case of complicated appendicitis. Post-operative pain is diminished and resumption of normal activity is quicker with the laparoscopic approach. Hospitalization is shorter but the cost of hospital care is higher; nevertheless, the global cost may be less - particularly for patients whose return to work is hastened by a laparoscopic approach. Laparoscopy diminishes the number of normal appendectomies, particularly in women of reproductive age where the diagnosis may be unclear. Laparoscopic appendectomy is practicable and has advantages over open appendectomy under certain circumstances. These advantages are most evident in the young female, the working patient, and the obese patient. Overall, the advantages of laparoscopy are, at best, modest and clinical benefit is not always demonstrable. The risk of deep abscess, particularly in patients with perforated or gangrenous appendicitis, remains an unknown and should be evaluated by further studies.