Bacterial pathogens in pediatric appendicitis: a comprehensive retrospective study

Abstract

BackgroundAppendicitis is a frequent condition, with peak incidences in the second decade of life. Its pathogenesis is under debate, but bacterial infections are crucial, and antibiotic treatment remains essential. Rare bacteria are accused of causing complications, and various calculated antibiotics are propagated, yet there is no comprehensive microbiological analysis of pediatric appendicitis. Here we review different pre-analytic pathways, identify rare and common bacterial pathogens and their antibiotic resistances, correlate clinical courses, and evaluate standard calculated antibiotics in a large pediatric cohort.MethodWe reviewed 579 patient records and microbiological results of intraoperative swabs in standard Amies agar media or fluid samples after appendectomies for appendicitis between May 2011 and April 2019. Bacteria were cultured and identified via VITEK 2 or MALDI-TOF MS. Minimal inhibitory concentrations were reevaluated according to EUCAST 2022. Results were correlated to clinical courses.ResultsOf 579 analyzed patients, in 372 patients we got 1330 bacterial growths with resistograms. 1259 times, bacteria could be identified to species level. 102 different bacteria could be cultivated. 49% of catarrhal and 52% of phlegmonous appendices resulted in bacterial growth. In gangrenous appendicitis, only 38% remained sterile, while this number reduced to 4% after perforation. Many fluid samples remained sterile even when unsterile swabs had been taken simultaneously. 40 common enteral genera were responsible for 76.5% of bacterial identifications in 96.8% of patients. However, 69 rare bacteria were found in 187 patients without specifically elevated risk for complications.ConclusionAmies agar gel swabs performed superior to fluid samples and should be a standard in appendectomies. Even catarrhal appendices were only sterile in 51%, which is interesting in view of a possible viral cause. According to our resistograms, the best in vitro antibiotic was imipenem with 88.4% susceptible strains, followed by piperacillin-tazobactam, cefuroxime with metronidazole, and ampicillin-sulbactam to which only 21.6% of bacteria were susceptible. Bacterial growths and higher resistances correlate to an elevated risk of complications. Rare bacteria are found in many patients, but there is no specific consequence regarding antibiotic susceptibility, clinical course, or complications. Prospective, comprehensive studies are needed to further elicit pediatric appendicitis microbiology and antibiotic treatment.

Flow cytometric characterization of cecal appendix lymphocyte subpopulations in children: a pilot study

“…However, this mechanism is not observed in all cases [ 1 ]. It has also been proposed that appendiceal inflammation may be secondary to a tumor, a foreign body or an infection (viral or bacterial) [ 3 – 5 ].…”

The Importance of Intraoperative Culture Swabs for The Management of Patients With Complicated Appendicitis Who Undergoing Laparoscopic Appendectomy

“…Antimicrobial therapy in appendicitis patients is essential for both empirical and postoperative treatment. For many surgeons, the standard has been resection alone with single-shot antibiotics, while real antibiotic treatment is only in cases of perforation or peri typhlitic abscess (1,12,14) .…”

“…Obtaining intraoperative culture swabs (IOCS) in appendectomy patients is important to identify the pathogen and adjust the antibiotic regimen. Peña et al (13) and Felber et al (14) reported that IOCS can help in knowing antibiotic resistance patterns in a specific population or institution, and therefore guide the most effective empiric antibiotic regimen in patients undergoing LA rather than being blindly treated. In a cohort study conducted by Coccolini et al (15) on 1431 AA patients, they reported that antimicrobial resistance was strictly linked to the clinical outcome of the patients and adequate empirical antimicrobial therapy being guided by microbiological swab results is fundamental to counteract bacterial resistance and cutting down postoperative complications.…”

“…There has been a major controversy raised about the benefit of microbiological swab usage in appendectomy patients last decades, some surgeons support its routine application (10,15,17) , while other surgeons are against it (18,19) . Others suggest that culture and sensitivity may be of value only in special patients such as high-risk and immunocompromised patients in whom there is an increased risk of non-resolution of intra-abdominal infections (1,14) .…”

Appendix: “an appendage to a twelve-meter gut or a storehouse for microbiota”?

“…Несмотря на то что первое подробное исследование аппендиколита было проведено еще в 1966 г., сведения об аппендикулярных конкрементах скудны [12]. Обструкция просвета аппендикса, вызванная аппендиколитом, лимфоидной гиперплазией или отеком, считалась основной причиной аппендицита, а избыточный бактериальный рост рассматривался как следствие [13,14]. Несмотря на неопределенность в отношении последовательности событий, ведущих к развитию аппендицита, в настоящее время предполагается, что микробиом играет центральную роль в патогенезе развития воспаления.…”