Intra-abdominal and pelvic emergencies

Treating Porcine Abscesses with Histotripsy: A Pilot Study

Infected abscesses are walled-off collections of pus and bacteria. They are a common sequela of complications in the setting of surgery, trauma, systemic infections and other disease states. Current treatment is typically limited to antibiotics with long-term catheter drainage, or surgical washout when inaccessible to percutaneous drainage or unresponsive to initial care efforts. Antibiotic resistance is also a growing concern. Although bacteria can develop drug resistance, they remain susceptible to thermal and mechanical damage. In particular, short pulses of focused ultrasound (i.e., histotripsy) generate mechanical damage through localized cavitation, representing a potential new paradigm for treating abscesses non-invasively, without the need for long-term catheterization and antibiotics. In this pilot study, boiling and cavitation histotripsy treatments were applied to subcutaneous and intramuscular abscesses developed in a novel porcine model. Ultrasound imaging was used to evaluate abscess maturity for treatment monitoring and assessment of post-treatment outcomes. Disinfection was quantified by counting bacteria colonies from samples aspirated before and after treatment. Histopathological evaluation of the abscesses was performed to identify changes resulting from histotripsy treatment and potential collateral damage. Cavitation histotripsy was more successful in reducing the bacterial load while having a smaller treatment volume compared with boiling histotripsy. The results of this pilot study suggest focused ultrasound may lead to a technology for in situ treatment of acoustically accessible abscesses.

Gastric submucosal abscess caused by Edwardsiella tarda infection: a case report

Background

Edwardsiella tarda is a motile, facultatively anaerobic gram-negative bacillus that is isolated from a wide spectrum of animals in aquatic environments but rarely causes infection in humans. Here, we describe the case of a gastric submucosal abscess caused by E. tarda infection.

Case presentation

The patient was a 74-year-old man with a history of hypertension and chronic alcohol consumption who was admitted to our hospital for abdominal pain, appetite loss and vomiting. Contrast-enhanced computed tomography (CT) revealed choledocholithiasis in the common bile duct, a gastric wall abscess and an intra-abdominal abscess. Endoscopic ultrasound (EUS)-guided drainage with antibiotics successfully cured the patient.

Conclusion

The combination of CT, endoscopy and EUS-guided drainage with antibiotic therapy might be effective for diagnosis and treatment of a gastric submucosal abscess caused by E. tarda infection.

Endoscopic ultrasound guided versus surgical transrectal drainage of pelvic abscesses

BACKGROUND

Pelvic abscesses are common but only small case series reporting outcome of either endoscopic ultrasound (EUS) guided or surgical transrectal drainage have been reported.

METHODS

We performed a retrospective consecutive cohort study, assessing effectivity and safety of EUS guided or surgical transrectal drainage of previously untreated pelvic abscesses from all causes, diagnosed using CT scan between 09/2010 and 06/2014 in a Dutch teaching hospital.

RESULTS

Forty-six patients with comparable demographics, apart from stoma presence (p = .016), were included. The success rate after a single intervention was 83% in the EUS guided compared to 48% in the surgical transrectal drainage group (p = .013). However, the mean duration of drainage was threefold in the EUS group [42 versus 13 days (p = .001)]. The length of stay in hospital was similar for both EUS and surgical group [24 versus 20 days (p = .56)] as was abscess resolution during follow-up [78% versus 74%]. We recorded a total of 12 anastomotic leaks [3 versus 9]. In the occurrence of leakage, only one stoma was finally closed in each group.

CONCLUSION

EUS guided and surgical transrectal drainage of pelvic abscesses from any cause are safe, nonetheless EUS guided drainage(if feasible) seems more effective after a single treatment, with high overall cure rates.

Antimicrobial evaluation of quaternary ammonium polyethyleneimine nanoparticles against clinical isolates of pathogenic bacteria

Peritonitis is a disease caused by bacterial strains that have become increasingly resistant to many antibiotics. The development of alternative therapeutic compounds is the focus of extensive research, so novel nanoparticles (NPs) with activity against antibiotic-resistant bacteria should be developed. In this study, the antibacterial activity of quaternary ammonium polyethyleneimine (QA-PEI) NPs was evaluated against Streptococcus viridans, Stenotrophomonas maltophilia and Escherichia coli. To appraise the antibacterial activity, minimal inhibitory concentration (MIC), minimal bactericidal concentration and bactericidal assays were utilised with different concentrations (1.56-100 µg/ml) of QA-PEI NPs. Moreover, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and annexin V/propidium iodide toxicity assays were performed in cell cultures. MICs for S. maltophilia and E. coli isolates were 12.5 and 25 µg/ml, respectively, whereas the MIC for S. viridans was 100 µg/ml. Furthermore, the growth curve assays revealed that these QA-PEI NPs at a concentration of 12.5 µg/ml significantly inhibited bacterial growth for the bacterial isolates studied. On the other hand, QA-PEI NPs lacked significant toxicity for cells when used at concentrations up to 50 μg/ml for 48 h. The present findings reveal the potential therapeutic value of this QA-PEI NPs as alternative antibacterial agents for peritonitis, especially against Gram-negative bacteria.

Multidrug-Resistant Gram-Negative Bacterial Infections in the Hospital Setting: Overview, Implications for Clinical Practice, and Emerging Treatment Options

The increasing prevalence of infections due to multidrug-resistant (MDR) gram-negative bacteria constitutes a serious threat to global public health due to the limited treatment options available and the historically slow pace of development of new antimicrobial agents. Infections due to MDR strains are associated with increased morbidity and mortality and prolonged hospitalization, which translates to a significant burden on healthcare systems. In particular, MDR strains of Enterobacteriaceae (especially Klebsiella pneumoniae and Escherichia coli), Pseudomonas aeruginosa, and Acinetobacter baumannii have emerged as particularly serious concerns. In the United States, MDR strains of these organisms have been reported from hospitals throughout the country and are not limited to a small subset of hospitals. Factors that have contributed to the persistence and spread of MDR gram-negative bacteria include the following: overuse of existing antimicrobial agents, which has led to the development of adaptive resistance mechanisms by bacteria; a lack of good antimicrobial stewardship such that use of multiple broad-spectrum agents has helped perpetuate the cycle of increasing resistance; and a lack of good infection control practices. The rising prevalence of infections due to MDR gram-negative bacteria presents a significant dilemma in selecting empiric antimicrobial therapy in seriously ill hospitalized patients. A prudent initial strategy is to initiate treatment with a broad-spectrum regimen pending the availability of microbiological results allowing for targeted or narrowing of therapy. Empiric therapy with newer agents that exhibit good activity against MDR gram-negative bacterial strains such as tigecycline, ceftolozane-tazobactam, ceftazidime-avibactam, and others in the development pipeline offer promising alternatives to existing agents.