Frequency of portal and systemic bacteremia in acute appendicitis

Integrative metagenomic and metabolomic analyses reveal the potential of gut microbiota to exacerbate acute pancreatitis

Early dysbiosis in the gut microbiota may contribute to the severity of acute pancreatitis (AP), however, a comprehensive understanding of the gut microbiome, potential pathobionts, and host metabolome in individuals with AP remains elusive. Hence, we employed fecal whole-metagenome shotgun sequencing in 82 AP patients and 115 matched healthy controls, complemented by untargeted serum metabolome and lipidome profiling in a subset of participants. Analyses of the gut microbiome in AP patients revealed reduced diversity, disrupted microbial functions, and altered abundance of 77 species, influenced by both etiology and severity. AP-enriched species, mostly potential pathobionts, correlated positively with host liver function and serum lipid indicators. Conversely, many AP-depleted species were short-chain fatty acid producers. Gut microflora changes were accompanied by shifts in the serum metabolome and lipidome. Specifically, certain gut species, like enriched Bilophila wadsworthia and depleted Bifidobacterium spp., appeared to contribute to elevated triglyceride levels in biliary or hyperlipidemic AP patients. Through culturing and whole-genome sequencing of bacterial isolates, we identified virulence factors and clinically relevant antibiotic resistance in patient-derived strains, suggesting a predisposition to opportunistic infections. Finally, our study demonstrated that gavage of specific pathobionts could exacerbate pancreatitis in a caerulein-treated mouse model. In conclusion, our comprehensive analysis sheds light on the gut microbiome and serum metabolome in AP, elucidating the role of pathobionts in disease progression. These insights offer valuable perspectives for etiologic diagnosis, prevention, and intervention in AP and related conditions.

The Sepsis Bundle Effect: An Evaluation of Culture Results and Utilization in Pediatric Appendicitis

INTRODUCTION

Sepsis prevention pathways, which often include blood and urine cultures, are common in children's hospitals. Fever and tachycardia, signs often seen in patients with appendicitis, frequently trigger these pathways. We hypothesized that cultures were frequently obtained in children with appendicitis.

MATERIALS AND METHODS

We conducted a single-center retrospective cohort study evaluating children with image-confirmed appendicitis from 4/1/2019 to 10/1/2020, coinciding with the initiation of sepsis prevention pathways. Factors associated with culture acquisition, as well as culture results, treatment, and outcomes were evaluated.

RESULTS

Six hundred and fifty eight children presented with acute appendicitis during the 1.5-year period, with a median age of 10.67 years (interquartile range (IQR) 8.17-14.08). Cultures were obtained in 22.9%, including blood culture (BCx) in 8.1% and urine culture (UCx) in 17.9%. Culture acquisition decreased by 17.6% after sepsis protocol initiation. Blood culture acquisition correlated with fever (P = .003) and younger age (P = .03), whereas the attainment of BCx and UCx was associated with female sex (P = .04, P < .0001), complicated appendicitis (P = .0001, P = .03), and unknown diagnosis (P < .0001, P < .0001). There were five positive UCx (4.24%); however, all remained asymptomatic despite a short antibiotic duration dictated by institutional appendicitis protocol. The one positive BCx (1.89%) was suspected contamination and not treated.

DISCUSSION

The findings of this cohort suggest a low incidence of positive culture as well as lack of impact on clinical management in image-proven appendicitis and the initiation of a sepsis bundle without automatic culture acquisition may result in decreased culture attainment.

Blood culture positivity in patients with acute appendicitis: A propensity score-matched prospective cohort study

BACKGROUND AND OBJECTIVE

The prevalence of bacteremia in acute appendicitis is unknown. We aimed to assess prevalence and predictive factors of bacteremia in adult patients with appendicitis.

METHODS

In this prospective propensity score-matched cohort study, patients were recruited as part of one single-center prospective observational study assessing appendicitis microbiology in concurrence with two randomized controlled trials on non-operative treatment of uncomplicated acute appendicitis. All patients evaluated for enrollment in these three trials between April 2017 and December 2018 with both a confirmed diagnosis of appendicitis and available blood culture on admission were included in this study. Potential predictive factors of bacteremia (age, sex, body mass index (BMI), body temperature, C-reactive protein (CRP), leukocyte count, comorbidities, symptom duration, and appendicitis severity) were assessed. Prevalence of bacteremia was determined by all available blood cultures followed by propensity score matching using sex, age, BMI, CRP, leukocyte count, and body temperature of the patients without available blood culture.

RESULTS

Out of the 815 patients with appendicitis, 271 patients had available blood culture and the prevalence of bacteremia was 12% (n = 33). Based on propensity score estimation, the prevalence of bacteremia in the whole prospective appendicitis cohort was 11.1%. Bacteremia was significantly more frequent in complicated acute appendicitis (15%; 29/189) compared with uncomplicated acute appendicitis (5%; 4/82) (p = 0.015). Male sex (p = 0.024) and higher body temperature (p = 0.0044) were associated with bacteremia.

CONCLUSIONS

Estimated prevalence of bacteremia in patients with acute appendicitis was 11.1%. Complicated appendicitis, male sex, and higher body temperature were associated with bacteremia in acute appendicitis.

Hyperbilirubinemia as a Possible Predictor of Appendiceal Perforation in Acute Appendicitis: A Prospective Study

Introduction: Acute appendicitis, a common abdominal surgical emergency, can mostly be diagnosed clinically by assessing the symptoms and physical findings but confirmation of the diagnosis solely depends upon the histopathological study of the resected appendix specimen, being supplemented by a few laboratory tests and ultrasonography (USG). In spite of all these available investigations, the diagnosis of acute appendicitis, because of its nebulous presentation and the variability of signs, remains a Herculean task for the surgeon.

Methods: This is a prospective study conducted on 125 patients diagnosed with acute appendicitis and posted for appendicectomy. Total serum bilirubin (TSB), and total leucocyte count (TLC) were done in all cases. USG of the abdomen was done in all the cases to confirm the diagnosis and to rule out other causes of acute abdomen. TLC more than 11 x 10³ cells/µL and TSB more than 1.1 mg/dL were considered positive. They were operated on and their diagnoses were confirmed post-operatively by histopathological examination. Patients were subdivided according to histopathological findings into: normal appendix (n = 11), uncomplicated acute appendicitis (n = 86), gangrenous appendicitis (n = 10) and perforated appendix (n = 18). Laboratory results, operative findings, and histopathological findings were compiled, analyzed, and compared with reference values.

Results: Out of 125 patients, 114 (91.2%) were histologically positive for acute appendicitis, while 11 (8.8%) had normal histology. TLC was elevated in 95 (76 %) patients and it was normal in 30 (24%) cases. Among the patients with leucocytosis, only 90 (94.74%) had positive histology for acute appendicitis, while the remaining five (5.26%) had normal histology. Among the 30 patients who had normal TLC, 24 had positive histology for acute appendicitis, while the remaining six had normal histology. The specificity, sensitivity, positive predictive value (PPV), and negative predictive value (NPV) were 78.95%, 54.55%, 94.74%, and 20%respectively. Similarly, 67 patients (53.6%) had elevated TSB, while it was within normal limits in 58 (46.4%) patients. From the patients with hyperbilirubinemia, 65 (97.01%) had positive histology for acute appendicitis, while the remaining two (2.99%) had normal histology. Among 58 patients who had normal TSB, 49 had positive histology for acute appendicitis, while the rest nine had normal histology. The specificity, sensitivity, PPV, and NPV are 57.02%, 81.82%, 97.01%, and 15.52% respectively. However, when both TLC and TSB were compared as markers of appendicular perforation, the sensitivity, specificity, PPV, and NPV of total serum bilirubin were found to be 89.29% against 21.43%; 53.49% vs. 2.33%; 38.46% vs. 6.67% and 93.88% vs. 8.33% of total leukocyte counts respectively.

Conclusion: Elevated total serum bilirubin could be used as a better predictor of appendiceal perforation in acute appendicitis.

Hidden diagnosis behind viral infection: the danger of anchoring bias

Anchoring bias is one of the most common diagnostic biases that may lead to closed-minded thinking and could result in unnecessary tests, inappropriate patient management and even misdiagnosis. A 4-year-old boy was brought to the emergency department because of shaking chills. On the basis of bilateral swollen preauricular areas, high level of serum amylase and the prevalence of mumps, he initially received a diagnosis of mumps in spite of the shaking chills. However, blood culture turned out to be positive for two different kinds of bacteria. The patient finally received a diagnosis of polymicrobial bacteraemia resulting from suppurative appendicitis. We must consider and rule out bacteraemia in the differential diagnosis for patients who present with shaking chills, even in the presence of symptoms or information consistent with a more common viral infection such as mumps. In addition, intra-abdominal infection should be ruled out in the presence of polymicrobial enterobacteriaceae bacteraemia.

Portal vein thrombosis

Portal vein thrombosis (PVT) is a rare event in the general medical setting that commonly complicates cirrhosis with portal hypertension, and can also occur with liver tumors. The diagnosis is often incidental when a thrombus is found in the portal vein on imaging tests. However, PVT may also present with clinical symptoms and can progress to life-threatening complications of ischemic hepatitis, liver failure, and/or small intestinal infarction. This article reviews the pathophysiology of this disorder, with a major focus on PVT in patients with cirrhosis, and presents detailed guidelines on optimal diagnostic and therapeutic strategies.

A "shocking" appendicitis

We report a case of Klebsiella oxytoca sepsis as a complication of nonperforated appendicitis in an 11-year-old immunocompetent boy. Even if septicemia is not mentioned in major reviews as a complication of nonperforated appendicitis, several cases have occasionally been reported in adult patients in the literature. The pathogenesis of sepsis with nonperforated appendicitis is still not clear, but a mechanism of bacterial translocation has been taken into account to explain the spread of microorganisms from the intestinal lumen to the systemic blood stream. Clinicians should therefore be aware of this occurrence.

[Portal vein thrombosis associated with biliary tract infection]

OBJECTIVE

To describe the etiology, symptoms and management of portal vein thrombosis associated with biliary tract infection and to compare our findings with classical causes of pylephlebitis.

MATERIAL AND METHODS

We performed a retrospective descriptive study of 10 patients in a tertiary hospital.

RESULTS

Portal vein thrombosis was associated with biliary tract infection in seven patients and with classical causes of pylephlebitis in three. In both groups, symptoms consisted of fever and abdominal pain accompanied by leukocytosis and increased liver enzymes. Blood cultures were positive in most patients and the main complication was liver abscess. The therapeutic management and outcomes were similar in both groups.

CONCLUSIONS

Portal vein thrombosis can be associated with biliary tract infection. Clinical presentation and outcomes are highly similar to those in classical causes of pylephlebitis.

Pseudomonas aeruginosa bacteraemia in an adult with cystic fibrosis and acute appendicitis

Despite their high bacterial load, bacteraemia is rare in patients with cystic fibrosis (CF). We report an adult with CF who developed Pseudomonas aeruginosa bacteraemia during an episode of acute appendicitis. The Pseudomonas aeruginosa isolated from the blood culture was confirmed by molecular typing to be the same transmissible strain responsible for the patient's chronic pulmonary infection. We hypothesise that this patient's bacteraemia was caused by Pseudomonas aerunginosa in swallowed sputum, crossing the inflamed appendiceal wall and entering the blood stream.

Alterations of the preoperative coagulation profile in patients with acute appendicitis

Acute appendicitis (AA) is usually associated with a systemic inflammatory response that often leads to activation of coagulation. However, limited data about coagulation changes in AA are available.

Results of preoperative coagulation testing in 702 patients with confirmed AA and 697 patients undergoing minor elective surgery (control) during the same period were analyzed retrospectively. Coagulation activity of factors VII, IX (FVII:C, FIX:C) and the concentration of plasma endotoxin from 40 patients with AA and 15 control subjects were measured.

Compared with control subjects, prothrombin time (PT), fibrinogen (Fib) and endotoxin increased (all p<0.01), FVII:C decreased (p<0.05), and thrombin time shortened (p<0.01) significantly in patients with AA, which showed trends with increasing severity of disease. Areas under the receiver operating characteristic curve of Fib for discriminating complicated appendicitis or acute perforated appendicitis from enrolled patients were larger than those for leukocyte parameters. The concentration of endotoxin correlated negatively with FVII:C (r=−0.860, p<0.001), positively with PT (0.713, <0.001), and FVII:C negatively with PT (−0.729, <0.001) in individuals that were evaluated. The change in activated partial thromboplastin time and difference in FIX:C among patients with various pathological types of appendicitis were not significant.

Endotoxin-induced activation of the extrinsic coagulation pathway was present in patients with AA. Fib may be useful as a potential indicator for excluding complicated appendicitis.

Anti-lipopolysaccharide antibodies in acute appendicitis detected by ELISA

In acute appendicitis the bowel transmissibility of the intestinal flora increases in relation to inflammation and edema formation. We can therefore observe an immunologic response in patients, which is detectable using different bacteria isolated from the normal intestinal flora. Our aim was to measure this immunologic reaction and to detect the relationship between this response and histologic types of acute appendicitis. Sera from 47 cases, comprising 38 patients suffering from appendicitis and 9 healthy controls, were examined. The sera were taken shortly before appendectomy and 14 days after operation. The antigens were lipopolysaccharides (LPS) extracted from bacteria of normal intestinal flora: Escherichia coli O21, O22, O33, O61, O68, Bacteroides fragilis and an absolute rough mutant: Shigella sonnei Re 4350. Antibodies were detected by ELISA. We showed a direct relationship between severity of appendicitis and registered antibody titer. Both aerobic and anaerobic bacteria play a role in infection in appendicitis. According to our serologic results the synergy of B. fragilis with E. coli from normal flora is more important in the initiation of inflammation, but in the perforation process the role of E. coli seems more important compared to that of B. fragilis.

Role of appendicitis and appendectomy in the pathogenesis of ulcerative colitis: a critical review

Besides a genetic predisposition, a causal role of various environmental factors has been considered in the etiology of ulcerative colitis (UC). The association between appendectomy and UC has recently been the subject of intense scrutiny in the hope that it may lead to the identification of important pathogenetic mechanisms. Published data from animal models of colitis demonstrated reduction in experimental colitis after appendectomy, especially if performed at an early age. Several epidemiological case control and cohort studies have shown a strong and consistent relationship. The metaanalysis of 17 case-controlled studies showed an overall odds ratio 0.312 (95% confidence intervals = 0.261-0.373) in favor of appendectomy (p < 0.0001). One of the two recent large cohort studies is in agreement with these results, but the other failed to confirm them. All these studies have suggested that alterations in mucosal immune responses leading to appendicitis or resulting from appendectomy may negatively affect the pathogenetic mechanisms of UC. Further investigation of the role of appendectomy in UC is expected to open new fields for basic scientific research and may lead to the improvement of our understanding for the disease pathogenesis.