Microbiologic Analysis of Complicated and Uncomplicated Acute Appendicitis

Optimizing antibiotic management for patients with acute appendicitis: A quality improvement study

BACKGROUND

To decrease surgical site infections after appendectomy for acute appendicitis, preoperative broad-spectrum antibiotics are often used in clinical practice. However, this treatment strategy has come under scrutiny because of increasing rates of antibiotic-resistant infections.

METHODS

The aim of this multisite quality improvement project was to decrease the treatment of uncomplicated acute appendicitis with piperacillin-tazobactam without increasing the rate of surgical site infections. Our quality improvement intervention had 2 distinct components: (1) updating electronic health record orders to encourage preoperative administration of narrow-spectrum antibiotics and (2) educating surgeons and emergency department clinicians about selecting appropriate antibiotic therapy for acute appendicitis. Patient demographics, clinical characteristics, and outcomes were compared 6 months before and after implementation of the quality improvement intervention.

RESULTS

A total of 352 laparoscopic appendectomies were performed during the 6-month preintervention period, and 369 were performed during the 6-month postintervention period. The preintervention period and postintervention period groups had similar baseline demographics, vital signs, and laboratory test values. The rate of preoperative piperacillin-tazobactam administration significantly decreased after the intervention (51.4% preintervention period vs 20.1% postintervention period, P < .001). The rate of surgical site infections was similar in both groups (superficial surgical site infections = 1.4% preintervention period vs 0.8% postintervention period, P = .50; deep surgical site infections = 1.1% preintervention period vs 0.0% postintervention period, P = .06; and organ space surgical site infections = 3.1% preintervention period vs 3.0% postintervention period, P > .99). Rates of 30-day readmission, reoperation, and Clostridioides difficile infection also did not differ between groups.

CONCLUSION

Our quality improvement intervention successfully decreased piperacillin-tazobactam administration without increasing the rate of surgical site infections in patients with acute appendicitis.

Intraoperative bacterial cultures fail to reliably predict the bacterial spectrum encountered during infectious complications after appendicitis

Acute appendicitis is a common surgical emergency. Complicated appendicitis usually warrants perioperative antibiotic treatment in order to prevent infectious complications. Whether routine microbiological testing benefits the individual patient is a topic of debate. The goal of our study was to assess perioperative antibiotic prescriptions as well as the benefit of microbiological testing during the appendectomy as a predictor for bacteria encountered in infectious complications. This is a retrospective analysis of 1218 consecutive patients that underwent appendectomy at a tertiary referral center between 2014 and 2021. The patient charts were systematically analyzed regarding intraoperative outcome, microbiologic results, and postoperative infectious complications. 1218 patients were included in this study of which 768 were uncomplicated appendicitis (UA) and 450 were complicated appendicitis (CA). Microbiological testing was performed in 39.2% of UA cases (33.6% of which grew bacteria) compared to 74.9% of CA cases (78.6% positive cultures). The strongest individual predictors for SSI were gangrenous and perforated appendicitis. A total of 58 surgical-site infections developed, of which 49 were intra-abdominal fluid collections or abscesses. Thirty-two patients had revision surgery or CT-guided drainage for SSI. In the cases where microbiological testing was done both during the appendectomy and the SSI, 13/18 showed different bacteria on culture testing. The infectious outcome was favorable in 98.3%. While microbiological testing offers insights into resistance patterns, it is of little benefit for the individual patient, given the low predictive value for bacteria found during SSI. Achieving source control combined with empiric antibiotic coverage leads to favorable outcomes independent of culture results.

Using Microbiology Culture in Pediatric Appendicitis to Risk Stratify Patients: A Cohort Study

Background: We sought to investigate the value of intra-operative microbiology samples in pediatric appendicitis. Proposed benefits include tailoring post-operative antimicrobial management, risk-stratifying patients, and reducing post-operative intra-abdominal abscess formation. Patients and Methods: All cases of appendicitis managed with appendicectomy in a single center were collected from January 2015 to August 2020. Intra-operative microbiology samples were taken routinely. Post-operative outcomes were analyzed with reference to culture and sensitivity results. Histologic findings were further categorized as normal, simple, or complex. Results: Six hundred seventy-eight children had appendicectomies, and 608 had both microbiology and histology samples taken. Intra-abdominal fluid collection and subsequent intervention rates were 22% and 9%, respectively. There were more collections in those with a culture positive result (p < 0.001), and those growing each of three recognized organisms, Escherichia coli (p < 0.001), Pseudomonas aeruginosa (p = 0.01), and Streptococcus anginosus group (p < 0.001). Intervention rate was higher in the culture-positive result group (p = 0.002) and the Streptococcus anginosus group (p < 0.001). Conclusions: This study shows an increased risk of developing a collection with the isolation of one of three key organisms (Escherichia coli, Pseudomonas aeruginosa, Streptococcus anginosus group). Sersoal swabs are an effective and practical method of gathering information on organisms. Microbiologic yield was correlated to the severity of appendicitis. Isolation of Streptococcus anginosus increases the incidence of collections to 50%. This is useful to empower surgeons to prognosticate patients' potential outcomes based on both intra-operative, and microbiologic findings, and is useful in counseling patients and managing expectations. A prolonged course of antibiotic agents or higher dose may mitigate this risk.

Implications of bacteriological study in complicated and uncomplicated acute appendicitis

Purpose

Bacteriological sample in the presence of intraabdominal free fluid is necessary to adapt the antibiotherapy and to prevent the development of resistance. The aim was to evaluate the differences between uncomplicated (UAA) and complicated acute appendicitis (CAA) in terms of bacterial culture results and antibiotic resistance, and to evaluate the factors linked with CAA.

Methods

We performed a single-center, retrospective observational study of all consecutive patients who presented with appendicular peritonitis and underwent emergent surgery in a tertiary referral hospital in Brussels, Belgium, between January 2013 and December 2020. The medical history, parameters at admission, bacterial culture, antibiotic resistance, and postoperative outcomes of 268 patients were analyzed. UAA was considered catarrhal or phlegmonous inflammation of the appendix. CAA was considered gangrenous or perforated appendicitis.

Results

Positive microbiological cultures were significantly higher in the CAA group (68.2% vs. 53.4%). The most frequently isolated bacteria in UAA and CAA cultures were Escherichia coli (37.9% and 48.6%). Most observed resistances were against ampicillin (28.9% and 21.7%) and amoxicillin/clavulanic acid (16.4% and 10.5%) in UAA and CAA, respectively. A higher Charlson comorbidity index, an elevated white blood cell count, an open procedure, and the need for drainage were linked to CAA. Culture results, group of bacterial isolation, and most common isolated bacteria were not related to CAA.

Conclusion

CAA presented a higher rate of positive cultures with increased identification of gram-negative bacteria. Bacterial culture from the peritoneal liquid does not reveal relevant differences in terms of antibiotic resistance.

[The importance of microbiological results for the treatment of complicated appendicitis-a monocentric case-control study]

BACKGROUND

Patients with complicated appendicitis frequently develop postoperative septic complications. There are no uniform standards for the choice of perioperative antibiotic prophylaxis and the duration of postoperative antibiotic treatment. The purpose of this study was to investigate associations between microbiological samples and postoperative complications.

METHODS

Patients with appendectomy and positive intraoperative swabs during 2013-2018 were included in this case-control study. Pathogen classes and their resistance patterns were evaluated in initial and follow-up swabs and compared in each of the groups with and without complications.

RESULTS

A total of 870 patients underwent surgery during the period studied. Pathogen detection succeeded in 102 of 210 cases (48.6%) with suspected bacterial peritoneal contamination. Conversion from laparoscopic to open intra-abdominal perforation and the presence of an abscess were independent risk factors for wound infections in the multivariate analysis. The combination of different classes of pathogens resulted in significantly increased overall resistance to ampicillin/sulbactam in both the initial swabs (57%) and the follow-up swabs (73%). Resistant E. coli strains combined with certain anaerobes were also regularly detected in postoperative intra-abdominal abscesses. Piperacillin/tazobactam was effective against 83% of positive swabs in our resistance tests.

CONCLUSION

Surgical treatment for complicated appendicitis remains the central therapeutic column. A regular review of the existing resistance patterns in perforated appendicitis can help to adjust and improve antibiotic treatment. Piperacillin/tazobactam should be used cautiously as a reserve antibiotic. A valid alternative is second or third generation cephalosporins in combination with metronidazole.

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.

Clinical, Laboratory and Radiographic Features Associated With Prolonged Hospitalization in Children With Complicated Appendicitis

OBJECTIVE

In children with appendicitis, rupture of the appendix is associated with a significant increase in morbidity. We sought to characterize the spectrum of illness in children with complicated appendicitis and to define those factors associated with a longer hospital stay.

STUDY DESIGN

We conducted a retrospective review of 132 children, 18 years of age or younger at a large urban teaching hospital in the Bronx, NY between October 2015 and April 2018 with an intraoperative diagnosis of perforated appendix. Clinical, laboratory and radiologic findings were reviewed, and the primary study outcome was length of stay (LOS) dichotomized at the median, which was 7 days. Statistical analyses were done to characterize morbidity and define variables predictive of longer stay.

RESULTS

Children in the longer LOS group experienced significantly more morbidity, including ICU stay, ileus, and need for multiple drainage procedures. A longer duration of symptoms prior to presentation was associated with a longer stay. Multivariable logistic regression analysis indicated that the presence of abscess and presence of free fluid in the right upper quadrant (RUQ FF) on initial imaging and C-reactive protein (CRP) level >12 at admission, were independently associated with a longer stay.

CONCLUSION

There is considerable variation in the morbidity of complicated appendicitis. The association between longer stay and the findings of abscess and RUQ FF on initial imaging along with an elevated CRP may provide a useful tool in identifying those children at risk for worse outcomes.

The intraperitoneal bacteriology and antimicrobial resistance in acute appendicitis among children: a retrospective cohort study between the years 2007-2017

This study aims to describe the microbiology and susceptibility profile of the intraperitoneal flora in complicated appendicitis. It is a retrospective cohort study including children < 18-year-old with pathologically confirmed appendicitis, from 2007 to 2017. It included 1466 children. Intraperitoneal samples were obtained from 655 (44.7%) patients, and 201 (30.7%) had positive culture with 395 pathogens. Gram-negative rods comprised 67.6%, Gram-positive cocci 21.5%, and anaerobes 10.9% of the isolates. Gram-positive cocci were detected in 67 (37.8%) patients. Milleri group Streptococci was the most frequently isolated Gram-positive (44.7%). The proportional rate of Milleri group Streptococci from Gram-positive cocci increased from 9.5 to 56.3% (P < 0.001, OR 12.214). Patients with Gram-positive cocci had longer hospital stay (mean 9.36 + 6.385 vs 7.72 + 4.582, P = 0.036, (CI -3.165, -0.105)) and more complicated disease (89.5% vs 78.4%, P = 0.045, OR 2.342). Patients with Milleri group Streptococci isolates readmitted more frequently (26.5% vs 13.2%, P = 0.05, OR 2.37). Resistance to amoxicillin-clavulanate, gentamicin, ceftazidime, piperacillin-tazobactam, and amikacin were detected in 29.1%, 6.5%, 2.3%, 1.2%, and 0.7% of the Gram-negative rods, respectively.Conclusion: The rates of Gram-positive cocci and particularly Milleri group Streptococci in peritoneal fluid are increasing. More complicated disease and longer hospital stay in Gram-positive cocci and higher readmission rate in Milleri group Streptococci. These emphasize the role of anti-Gram-positive antimicrobials. What is known: • Gram-negative rods are the main isolates in complicated appendicitis. • The choice of antibiotic regimen is an unsettled issue due to resistance. What is new: • Increased rate of Gram-positive cocci and Milleri group Streptococci. • More complicated disease, longer hospital stay, and higher readmission rate.

Pattern and Outcome of Acute Appendicitis: Observational Prospective Study from a Teaching Hospital, Addis Ababa, Ethiopia

Background

Acute appendicitis is the most common cause of acute abdomen surgery. Despite its commonness and the abundance of literature on the subject, its diagnosis remains challenging. Delay in intervention results in complications of the process leading to increased morbidity and mortality.

Methodology

An observational prospective cohort study was conducted, and all patients who had undergone appendectomy for a clinical diagnosis of appendicitis were included in the study. Data were analysed using Statistical Package for Social Sciences (SPSS) version 23.

Results

Half of the study participants were in the age range of 18–25 years with male preponderance (63.9%). The mean duration of symptoms was 51.3 hours. The most common presenting symptom was abdominal pain (98.2%), while right lower quadrant tenderness was the most common sign (93.4%). Abdominal ultrasound was done in 81% of the study population with a sensitivity and specificity of 95.7% and 33.3%, respectively. Three-quarters (74.4%) of the patients had uncomplicated appendicitis, while 1.8% had a grossly normal appendix. None of the appendectomy specimens were sent for pathology. The mean hospital stay was 3.2 days. The morbidity and mortality rate were 3.8% and 0.4%, respectively.

Conclusion

Acute appendicitis was the most common emergency surgical procedure in the study period. Abdominal ultrasound was used in the majority of the patients as supplementary imaging for the diagnosis of acute appendicitis. Uncomplicated appendicitis took the major share of the intraoperative finding leading to acceptable morbidity and mortality rates.

Optimal Duration of Antibiotics Following Appendectomy for Patients With Complicated Appendicitis

BACKGROUND

Complicated appendicitis patients typically undergo appendectomy followed by antibiotics. The optimal course of antibiotics for complicated appendicitis is poorly defined.

METHODS

Data were collected from patients presenting with acute appendicitis and underwent appendectomy at the index hospitalization (2015-2017). Primary outcomes were readmission rate, superficial surgical site infection (SSI), deep space infection (DSI), which includes abscess. Length of post-operative antibiotic use was recorded and an average intent-to-treat (ITT) by operative grade was calculated.

RESULTS

Two hundred seventy-two patients (23%) were diagnosed with complicated appendicitis. SSI occurred in 4% of patients (n = 11); SSI rates ranged from 0% to 14.6% by ITT group with 3-4 days being the lowest (0%) and <3 days the highest (14.6%) (P = .008). DSI including abscesses occurred in 27 (9.9%) patients; least frequently in the 5-6 day ITT group (7.4%). Length of stay (LOS) was significantly related to longer antibiotic use (P < .001) and increasing operative grade (P < .01).

CONCLUSIONS

Given the lower incidence of postoperative complications between 3 and 6 days and no added benefit for ITT >6 days, we recommend limiting antibiotic treatment to 3-6 days for all complicated appendicitis cases with additional workup warranted if infectious symptoms persist.

Narrow- versus Broad-Spectrum Antibiotics for Simple Acute Appendicitis Treated by Appendectomy: A Post Hoc Analysis of EAST MUSTANG Study

BACKGROUND

We sought to compare the effectiveness of narrow- versus broad-spectrum antibiotics (abx) in preventing infectious complications in adults with acute appendicitis treated with appendectomy.

METHODS

In this post hoc analysis of a prospective multicenter observational study of appendicitis in adults (≥18 y) conducted from January 2017 to June 2018, we included only patients with simple appendicitis. Subjects were grouped based on receipt of broad-spectrum or narrow-spectrum abx before and/or after appendectomy. Outcomes compared were surgical site infection, intra-abdominal abscess, secondary interventions (percutaneous drainage or operation), emergency department (ED) visits, 30-d readmission, and hospital length of stay.

RESULTS

A total of 2336 subjects were analyzed. In comparing narrow (n = 778) versus broad (n = 1558) groups, there were no differences in male sex (53% versus 54%, P = 0.704), white blood cell (13.0 ± 3.9 versus 13.4 ± 4.5, P = 0.05), Alvarado score (6 [5-7] versus 6 [5-7], P = 0.25), or Charlson comorbidity index (0 [0-1] versus 0 [0-1], P = 0.09). A total of 688 (29%) received postoperative abx, [184 (24%) narrow and 504 (32%) broad, P < 0.001] for a median 5 [2-7] d [42 (23%) narrow and 235 (47%) broad, P < 0.001]. There were no significant differences between narrow and broad groups in surgical site infection, intra-abdominal abscess, secondary interventions, ED visits, or hospital readmissions.

CONCLUSIONS

Significant practice variation in duration and spectrum of antibiotic adjunct for surgical treatment of simple acute appendicitis treatment is evident, and broad-spectrum abx did not offer clinical advantages over narrow-spectrum abx. Restriction of antibiotic spectrum should be considered, although randomized trials are required to overcome selection bias.

[Antibiotics alone as an alternative to appendectomy for uncomplicated acute appendicitis in adults: Changes in treatment modalities related to the COVID-19 health crisis]

La saturation intrahospitalière liée à l’arrivée massive de patients atteints du COVID-19 nécessitant une prise en charge urgente conduit à reconsidérer la prise en charge des autres patients. Différer au maximum les hospitalisations et les opérations chirurgicales non urgentes est un des objectifs des chirurgiens afin de désengorger autant que possible le système de soins. Alors que la majorité des opérations programmées sont annulées, la réduction de la chirurgie d’urgence est évidemment compliquée à proposer sans altérer la qualité de la prise en charge et conduire à une perte de chance pour le patient. Cependant, l’appendicite aiguë constitue une situation spécifique bien particulière et la fréquence de cette pathologie conduit à considérer ce cas particulier. En effet, tandis que le traitement recommandé de l’appendicite aiguë non compliquée est chirurgical, l’alternative non chirurgicale par antibiothérapie seule a été largement évaluée dans la littérature au cours de travaux de qualité. Dans la mesure où la limite principale du traitement médical exclusif de l’appendicite aiguë non compliquée est le risque de récidive à distance, cette option thérapeutique représente une alternative de choix pour réduire la surcharge intrahospitalière dans ce contexte de crise sanitaire. L’objectif de ce travail est donc de mettre à disposition des médecins et des chirurgiens un guide pratique issu d’une analyse de la littérature sur le traitement médical de l’appendicite aiguë non compliquée de l’adulte afin de pouvoir proposer ce traitement alternatif aux bons patients et dans des bonnes conditions, notamment lorsque l’accès au bloc opératoire est impossible.

Antibiotics alone as an alternative to appendectomy for uncomplicated acute appendicitis in adults: Changes in treatment modalities related to the COVID-19 health crisis

The massive inflow of patients with COVID-19 requiring urgent care has overloaded hospitals in France and impacts the management of other patients. Deferring hospitalization and non-urgent surgeries has become a priority for surgeons today in order to relieve the health care system. It is obviously not simple to reduce emergency surgery without altering the quality of care or leading to a loss of chance for the patient. Acute appendicitis is a very specific situation and the prevalence of this disease leads us to reconsider this particular disease in the context of the COVID-19 crisis. Indeed, while the currently recommended treatment for uncomplicated acute appendicitis is surgical appendectomy, the non-surgical alternative of medical management by antibiotic therapy alone has been widely evaluated by high-quality studies in the literature. Insofar as the main limitation of exclusively medical treatment of uncomplicated acute appendicitis is the risk of recurrent appendicitis, this treatment option represents an alternative of choice to reduce the intra-hospital overload in this context of health crisis. The aim of this work is therefore to provide physicians and surgeons with a practical guide based on a review of the literature on the medical treatment of uncomplicated acute appendicitis in adults, to offer this alternative treatment to the right patients and under good conditions, especially when access to the operating room is limited or impossible.

Recovery of aerobic and anaerobic bacteria from patients with acute appendicitis using blood culture bottles

Introducción.

La apendicitis aguda es la primera causa de abdomen agudo; sin embargo, poco se conoce sobre las bacterias asociadas y su perfil de sensibilidad.

Objetivo.

Identificar y determinar el patrón de resistencia de las bacterias aerobias y anaerobias aisladas en cultivo de líquido periapendicular tomado de los pacientes con apendicitis aguda, y establecer la proporción de bacterias según la fase clínica.

Materiales y métodos.

Se llevó a cabo un estudio descriptivo y prospectivo en el Hospital Universitario de San José de Bogotá (Colombia), en pacientes mayores de 16 años sometidos a apendicectomía abierta. Se tomaron muestras de líquido periapendicular, las cuales se sembraron directamente en botellas de hemocultivos para aerobios y anaerobios.

Resultados.

Se incluyeron 154 pacientes. Del total de cultivos, el 87 % (n=134) fueron positivos: 77 % (n=118) para aerobios y 51 % (n=79) para anaerobios. La proporción de cultivos positivos fue inferior en los casos de apendicitis no complicada, en comparación con aquellos de apendicitis complicada (80 % (66/83) Vs. 95 % (67/71); p=0,003). Los microorganismos aislados con mayor frecuencia fueron: Escherichia coli (53 %) (n=84), Bacteroides sp. (25 %) (n=25), Propionibacterium acnes (21 %) (n=21), Staphylococci coagulasa negativo (17 %) (n=27), Enterococcus sp. (10 %) (n=15) y Fusobacterium sp. (11 %) (n=11). La sensibilidad de E. coli a la amplicilina sulbactam fue de 30 %. La sensibilidad de Bacteroides spp. a la clindamicina y la ampicilina sulbactam fue de 91 %. El 100 % de los anaerobios fueron sensibles a piperacilina tazobactam, ertapenem, meropenem y metronidazol.

Conclusiones.

Los cultivos intraoperatorios son pertinentes en la apendicitis para determinar el patrón epidemiológico local, y establecer los antibióticos profilácticos y terapéuticos para esta enfermedad. Su siembra directa en botellas de hemocultivo permite una gran recuperación de microorganismos.

Preoperative assessment of complicated appendicitis through stress reaction and clinical manifestations

This study assessed the severity of the disease through the preoperative clinical manifestations and inflammatory reaction indicators of acute appendicitis, and established a score table to predict complicated appendicitis (CA).The clinical data of 238 patients with acute appendicitis in our hospital were retrospectively analyzed, which included 18 patients with acute simple appendicitis (7.6%), 170 patients with acute purulent appendicitis (72.0%), and 48 patients with acute gangrene and perforation (20.3%). The clinical manifestations and inflammatory reaction indicators were analyzed by univariate logistic regression. Multivariate logistic regression analysis was performed to screen out the independent risk factors of CA. The β coefficients of independent risk factors entering the multivariate model were assigned by rounding, and the total score was the sum of values of all factors. Finally, verification and analysis were performed for the predictive model, and the operating characteristic curve (ROC) curve was drawn. Then, the area under the curve (AUC) was compared with the THRIVE scale, and the Hosmer-Lemeshow method was used to evaluate whether the model fitted well.The multivariate logistic regression analysis of independent risk factors was performed, and the values were rounded to the variable assignment based on the β coefficient values. The plotted ROC and AUC was calculated as 0.857 (P < .001). Using the Hosmer-Lemeshow method, the X-value was 12.430, suggesting that the prediction model fitted well.The scoring system can quickly determine whether this is a CA, allowing for an earlier and correct diagnosis and treatment. Furthermore, the scoring system was convenient, economical, and affordable. Moreover, it is easy to popularized and promote.

Intraoperative cultures during appendectomy in children are poor predictors of pathogens and resistance patterns in cultures from postoperative abscesses

BACKGROUND

Intraoperative cultures are commonly sent in complicated appendicitis. Culture-guided antibiotics used to prevent postoperative infectious complications are debated. In this study, we describe the microbial overlap between intraoperative and abscess cultures, and antibiotic resistance patterns.

METHOD

A local register of a children's hospital treating children 0-15 years old with appendicitis between 2006 and 2013 was used to find cases with intraoperative cultures, and cultures from drained or aspirated postoperative intraabdominal abscesses. Culture results, administered antibiotics, their nominal coverage of the identified microorganisms, and rationales given for changes in antibiotic regimens were collected from electronic medical records.

RESULTS

In 25 of 35 patients who met inclusion criteria, there was no overlap between the intraoperative and abscess cultures. In 33 of 35 patients, all identified intraoperative organisms were covered with postoperative antibiotics. In 14 patients, organisms in the abscess culture were not covered by administered antibiotics. Enterococci not found in the intraoperative culture were found in 12 of 35 abscesses. We found no difference in the antibiotic coverage between rationales given for antibiotic changes.

CONCLUSION

The overlap between intraoperative cultures and cultures from subsequent abscesses was small. Lack of antibiotic coverage of intraoperative cultures was not an important factor in abscess formation.

The appropriateness of ceftriaxone and metronidazole as empirical therapy in managing complicated intra-abdominal infection-experience from Western Health, Australia

Purpose

This study aims to assess the microbiological profile, antimicrobial susceptibility and adequacy of intravenous ceftriaxone and metronidazole as empirical therapy for surgical patients presenting with complicated intra-abdominal infection.

Methods

This retrospective audit reviews the microbiological profile and sensitivity of intra-abdominal cultures from adult patients with complicated intra-abdominal infection who presented to the emergency department at Western Health (Melbourne, Australia) between November 2013 and June 2017. Using the hospital’s database, an audit was completed using diagnosis related group (DRG) coded data. Ethics approval has been granted by the Western Health Human Research Ethics Committee. Results are stratified according to surgical conditions (appendicitis, cholecystitis, sigmoid diverticulitis and bowel perforation). The antimicrobial coverage of ceftriaxone and metronidazole is evaluated against these microbial profiles.

Results

A total of 1,412 patients were identified using DRG codes for intra-abdominal infection. All patients with microscopy and sensitivity results were included in the study. Patients without these results were excluded. 162 patients were evaluable. 180 microbiological cultures were performed through surgical intervention or radiologically guided aspiration of the intra-abdominal infection. Single or multiple pathogens were identified in 137 cultures. The most commonly identified pathogens were mixed anaerobes (12.6%), Escherichia coli (E. coli) (12.1%), mixed coliforms (11.6%) and Pseudomonas aeruginosa (7%). Other common pathogens (6% each) included Enterococcus faecalis, Streptococcus anginosus, Vancomycin-resistant Enterococci (VRE) and Extended Spectrum Beta-Lactamases (ESBL) producing E. coli. Organisms isolated in our study are consistent with existing literature. However, a significant proportion of antibiotic resistant organisms was identified in cases of perforated bowel and sigmoid diverticulitis. Broader spectrum antimicrobial therapy should therefore be considered in lieu of ceftriaxone and metronidazole in these cases. Ceftriaxone and metronidazole remain as appropriate empirical therapy for patients who presented with perforated appendicitis and cholecystitis.

Discussion

The empirical regime of ceftriaxone and metronidazole remains appropriate for intra-abdominal infection secondary to appendicitis and cholecystitis. In cases involving perforated small and large bowel, including complicated sigmoid diverticulitis, the judicious use of ceftriaxone and metronidazole is recommended.