Paediatric Escherichia coli urinary tract infection: susceptibility trends and clinical management-a retrospective analysis of a 10-year period.

BACKGROUND: Escherichia coli is the predominant urinary pathogen in children. Irish and international studies have demonstrated increasing antimicrobial resistance (AMR) to antibiotics such as co-amoxiclav. AIMS: We aimed to (1) examine the AMR patterns of paediatric urinary E. coli isolates, from both hospital and community sources, over a 10-year period; (2) assess the effectiveness of Children's Health Ireland (CHI) antimicrobial guidance given local susceptibility data; and (3) review the clinical management of an admitted patient sub-set over a 6-year period. METHODS: Pure growth of urinary E. coli from patients aged ≤ 14 from 2012 to 2021 were analysed for AMR. Differences in susceptibility rates were assessed. A retrospective chart review conducted on inpatients aged ≥ 2 months to ≤ 14 years, 2016-2021. RESULTS: E. coli accounted for 70.8% of likely significant positive pure growth cultures (9314 isolates). Susceptibility to co-amoxiclav significantly increased over time, from 66.7% to 80.4% (2016-2021, p < 0.001). Nitrofurantoin and cefalexin had significantly higher susceptibility rates than trimethoprim (< 70% annually). 85.1% of isolates were susceptible to the combination of co-amoxiclav and gentamicin, recommended for those > 2months and systemically unwell. The additional gain in empiric susceptibility provided by gentamicin above that provided by co-amoxiclav alone has fallen from 16.4% to 6.7% (2016-2021). The 222 clinical cases reviewed showed improved antimicrobial guideline compliance over time. CONCLUSIONS: This study provides important regional AMR data. Co-amoxiclav susceptibility increased significantly over time, contrasting with previous studies. This was temporally associated with stewardship measures reducing co-amoxiclav prescribing. Decreasing utility of gentamicin supports recent CHI guideline updates reducing gentamicin use.

Case of recurrent Achromobacter xylosoxidans bacteraemia and PICC (peripherally-inserted central catheter) line infection in an immunocompromised patient.

BACKGROUND: This report describes recurrent A. xylosoxidans bloodstream and PICC (peripherally-inserted central catheter) line infection in an immunocompromised patient. PRESENTATION OF CASE: A 64-year-old female with acute promyelocytic leukaemia presented during a non-neutropenic febrile episode, and A. xylosoxidans was isolated from multiple PICC and peripheral blood cultures, and from the tip of the line on removal. The patient was treated with meropenem and a new PICC line was inserted after sterile blood cultures. Six weeks later, she represented with A. xylosoxidans from multiple cultures from the line. She was treated with piperacillin-tazobactam and the line was removed. There was no evidence of deep-seated infection. Further discussion revealed that the patient was using a sponge to clean, and a sleeve to cover her PICC-line while bathing. A. xylosoxidans was cultured from both the sponge and the swab. Whole Genome Sequencing performed on two blood culture isolated and both environmental isolates confirmed all four isolates were indistinguishable. The patient was advised not to use the sponge/sleeve in future and we have incorporated specific advice in this regard into our patient information. DISCUSSION: Achromobacter xylosoxidans is an aerobic, non-lactose fermenting gram-negative bacillus usually considered an opportunistic pathogen. It is associated with infection in immunocompromised patients, and is an emerging pathogen in catheter-related infections, sometimes associated with contaminated water. CONCLUSION: This case of recurrent A. xylosoxidans line infection highlights diagnostic and management challenges associated with catheter-related infections. Treatment is challenging because of intrinsic and acquired resistance mechanisms. Empiric treatment with anti-pseudomonal penicillins or carbapenems with line removal is typically required.