This prospective descriptive study involved 20 patients under 13 years of age who underwent an appendectomy for acute appendicitis at the Paediatric Surgical Department in Pelonomi Tertiary Hospital, Bloemfontein, from July 2023 to November 2023. The standard empiric treatment for acute appendicitis during the study period was amoxicillin-clavulanic acid adjusted to intraoperative pus swab microscopy, culture and sensitivity (MCS) results. Patients treated non-operatively and those with missing microbiology test results were excluded. All patients were referred from peripheral hospitals or clinics, and no data pertaining to initial antibiotics or stat treatment provided by the referral institutions were documented. A pus swab was taken during the appendectomy for MCS to determine the identified organisms and antimicrobial drug sensitivities. Agar plates were also incubated under anaerobic conditions for the isolation of potential anaerobes. No blood cultures were sent for analysis. All methods were performed according to the standard operating procedures (SOPs) of the local medical microbiology laboratory. Basic demographic information, appendicitis classification,²³ and MCS results were captured using REDCap (REDCap Consortium; Nashville, TN, US), an electronic data capturing tool hosted by the University of the Free State. Appendicitis is uncomplicated when confined to the appendix without perforation, abscess formation, or phlegmon, managed with appendectomy or occasionally antibiotics. Complicated cases involve perforation, abscess formation, or phlegmon, requiring surgery and prolonged antibiotics.^23,24

The Department of Biostatistics, Faculty of Health Sciences, UFS analysed the data using the statistical analysis software R (The R Foundation; Vienna, Austria).²⁵ The results were summarised as frequencies and percentages.

Ethical approval was obtained from the Health Sciences Research Ethics Committee (HSREC) of the University of the Free State (reference no. UFS-HSD2023/0465/2908) and the Free State Province Department of Health. Informed consent was obtained from the parents and/or legal guardians and assent from patients old enough to understand. Patient information was anonymised, and no identifying details were documented. Data were stored on REDCap, which was password-protected.

The study comprised 20 patients, of whom 12 (60%) were male. The ages ranged from 4 years to 12 years, with a mean of 8 years. All the surgical procedures were open appendectomies performed via a Lanz incision. Most patients had complicated appendicitis (n = 17; 85%). Short-term complications occurred in 6 patients (30%), including surgical site infection (n = 4), intra-abdominal pus collection (n = 1) and adhesive bowel obstruction (n = 1). There were no mortalities, and all patients were discharged from the hospital.

Table 1 shows the number of isolated bacteria in males and females. Escherichia coli was the most prevalent (n = 12; 60%). No bacterial growth was observed in 30% (n = 6) of cases. An extended-spectrum β-lactamase (ESBL) producing isolate (Enterobacter cloacae complex) was cultured from the pus specimen of one patient (n = 1/20; 5%). Bacteria isolated in the complicated appendicitis cases were E.coli (n = 4), Enterobacter cloacae complex (n = 1), and Pseudomonas aeruginosa (n = 1); no growth was observed in four cases.

Table 2 shows the antibiotic sensitivity and resistance of the isolated bacteria (n = 14). All isolates (n = 14; 100%) were susceptible to cefepime, amikacin, imipenem and meropenem, followed by a 92.9% (n = 13) sensitivity rate to ciprofloxacin, ceftazidime, gentamicin, piperacillin-tazobactam, ertapenem, colistin and tigecycline.

In six of the cases (42.9%), the bacteria showed resistance to ampicillin and/or amoxicillin, in five cases (35.7%) to trimethoprim-sulfamethoxazole and in three cases (21.4%) to amoxicillin-clavulanic acid. As shown in Table 2, no resistance was observed against cefepime, gentamicin, amikacin, ertapenem, imipenem, meropenem and colistin.

Our research showed that more cases of appendicitis occurred in males, with a male-to-female ratio of 1.5:1. This finding was consistent with several other South African studies on paediatric appendicitis, which consistently reported a male predominance.^22,26,27,28 The male majority supports underlying biological and environmental determinants. The mean age in our study was 8 years, matching previous findings.^22,26,27,28 This could indicate a constant age for paediatric appendicitis in South Africa.

Our research showed that there was no difference in species isolation between male and female patients. Escherichia coli was the most common organism, representing 85.7% of isolates. This was consistent with some studies (67% – 80%),^16,21,29,30 but showed a higher occurrence than others (28% – 50%).^18,31,32,33 Escherichia coli has been described as a notable cultured organism in appendicitis, indicating a diverse microbial profile in different groups.³⁴ This variation could imply that while E. coli is frequently isolated in paediatric acute appendicitis, its prevalence can differ based on location and population characteristics. Therefore, it is essential to consider this organism when prescribing antibiotics.³⁵ Understanding variations in antibiotic therapies can enhance treatment effectiveness, improve patient outcomes, and minimise complications from inappropriate treatment.

In our study, 30% (n = 6) of cases yielded no positive cultures, including four patients with complicated appendicitis (n = 4/6; 66.7%). These findings were consistent with recent literature, which reported a 39.2% rate of culture negativity in uncomplicated appendicitis cases.³⁶ The absence of growth in some cases might be because of the nature of the infection (less severe cases) or the effectiveness of prior empiric antibiotic therapy, although not documented in this study.²¹ This highlights the complexity of appendicitis and the limitations of microbiological testing in predicting infectious outcomes.³⁶ The findings underscore the importance of comprehensive clinical evaluation and using the most susceptible empiric antibiotic therapy for individual units to manage paediatric appendicitis effectively.

All 14 organisms isolated from these patients were susceptible to cefepime, amikacin, imipenem, meropenem, ertapenem and gentamicin, including E. coli, the most common isolate.^{16,18,29,30,32,33,37,38} Other paediatric studies identified cefuroxime-metronidazole and ampicillin-sulbactam combinations³⁹ as their most effective antibiotics.

Our study found an 85.7% sensitivity rate for cefotaxime-ceftriaxone, showing strong effectiveness, consistent with other studies.^18,32 Combining ceftriaxone with metronidazole can be more effective than cefoxitin alone in treating uncomplicated appendicitis and reducing postoperative complications.^40,41 Gentamicin had a 100% sensitivity rate, higher than the 68% – 82% range reported for aminoglycosides.^18,30,32,38 However, recent paediatric studies do not mention gentamicin.^39,40 The adverse effects associated with gentamicin, such as nephrotoxicity and ototoxicity, may limit its use.⁴² Clinicians should regularly monitor peak and trough levels when prescribing aminoglycosides to reduce the risk of adverse effects.⁴³ Aminoglycosides are also ineffective against anaerobes.^44,45 Therefore, adding metronidazole to the regimen in acute appendicitis cases is advisable,^40,41 even though no anaerobes were isolated in this study with a small sample size.

In our study, susceptibility to cefuroxime was observed in 78.6% of the bacterial isolates for oral products, and 85.7% for parenteral preparations, aligning with broader trends in susceptibility to this cephalosporin observed in recent studies.^18,21 Some Enterobacteriaceae produce ESBLs, conferring resistance to most β-lactam antibiotics, including new-generation cephalosporins. This may contribute to the cefuroxime sensitivity profile reported in the literature.²¹ It underscores the need for ongoing surveillance and adaptation of antibiotic regimens in clinical practice.

Our findings emphasise the necessity of customising antibiotic protocols based on local resistance patterns and clinical situations to improve outcomes. Continuous surveillance and region-specific research are essential for adjusting treatment protocols, especially given the global increase in antibiotic resistance.¹⁷ This approach enhances patient care and contributes to the global effort to promote antibiotic stewardship.

We found 42.9% resistance rates for ampicillin-amoxicillin, 35.7% for trimethoprim-sulfamethoxazole and 21.4% for amoxicillin-clavulanic acid, making them fairly unreliable as first-line treatment for appendicitis in our unit. The rates for ampicillin-amoxicillin and trimethoprim-sulfamethoxazole resistance are higher than those reported in recent studies (15% – 32%),^16,39,40 and reflect global concerns about increasing antibiotic resistance and the need for region-specific research to guide treatment.^17,30,33 The findings highlight the urgent need to determine alternative therapies and improved stewardship programmes to address resistance trends.

Cefoxitin showed a 14.3% resistance rate, which was not mentioned in recent paediatric appendicitis studies.^18,39,40 The resistance rate of 14.3% for cefotaxime and/or ceftriaxone was consistent with observed ranges for other antibiotics in paediatric appendicitis.^39,40 Because of this resistance rate, we will not consider these two antibiotics as empiric treatment in our setting. This suggests the need to evaluate the effectiveness of different antibiotic agents in paediatric populations and use combination therapies to help overcome resistance and improve patient outcomes.

It is generally advised to avoid using antibiotics with resistance rates between 10% and 20%.³⁰ Continuous monitoring of resistance patterns, adherence to guidelines and regular culture testing are crucial for tracking susceptibility, guiding antibiotic choices and ensuring effective treatments.

The study has several limitations. Data were collected from a single tertiary public sector hospital, with a small sample size and short time period of the study, limiting its generalisability of the findings. The use of empiric antibiotic treatment was not documented from either referring institutions or our own pre-operative regimens potentially biasing our culture results. This study can serve as a pilot study to more extensive research in our unit. Despite these limitations, the results align with previous studies, and antibiotic treatment regimens can be adjusted for the unit.

To optimise treatment outcomes, we recommend that empiric antibiotic treatment for acute appendicitis in our unit be changed to the local susceptibility patterns detected in this study. Intravenous ciprofloxacin and metronidazole can be used and then tailored to the susceptibility of the bacterial isolates based on the MCS results of the swabs taken intraoperatively. Given the high rate of susceptibility to ciprofloxacin, it can be used in empiric antibiotic therapy in acute appendicitis. Ciprofloxacin may cause adverse effects in 5% – 15% of paediatric patients,⁴⁶ although these events (musculoskeletal effects, abnormal liver functions, nausea and vomiting, and changes in white cell counts) are usually reversible⁴⁷ with no long-term sequelae. Cefepime also had a 100% susceptibility but will not be recommended for empiric treatment to preserve its effectiveness against P. aeruginosa, Serratia or Enterobacter infections in general. Future and ongoing regular culture testing should be conducted in all units to track susceptibility and guide antibiotic selection to ensure effective treatment of acute appendicitis in children.

Despite the 100% susceptibility in this study, using broad-spectrum antibiotics such as amikacin, imipenem, ertapenem and meropenem is discouraged for uncomplicated acute appendicitis because of stewardship concerns and potential drug resistance.⁴⁸ The Surgical Infection Society (SIS) guidelines recommend reserving these drugs for high-risk or severe cases and providing education to improved appropriate antibiotic use without adverse outcomes.⁴⁸ Simpler antibiotic regimens succeed in approximately 60% of uncomplicated cases, with outcomes comparable to surgery.^49,50 Overusing potent antibiotics increases risks such as Clostridium difficile colitis, resistance, and major complications, reinforcing the importance of careful antibiotic selection.^49,51

Metronidazole targets anaerobic bacteria such as Bacteroides fragilis, although not isolated in this study, possibly because of pre-operative antibiotic administration and the small sample size.^52,53,54 It is cost-effective, can be given orally and reduces hospital costs by about 30% in complicated cases.⁵⁴ It shortens hospital stays by about 1 day^53,54 and helps prevent postoperative infections in severe cases.⁵⁵ Its pharmacokinetics allow once-daily dosing.⁵⁶