Intra-abdominal infections caused by Achromobacter xylosoxidans: a systematic review

Abstract

Background:

Achromobacter xylosoxidans is an emerging cause of intra-abdominal infections, typically after healthcare exposure or in patients with indwelling devices. Intrinsic multidrug resistance and biofilm formation impede empiric therapy and often necessitate source control (catheter/stent exchange or removal). Because guidance is scattered across case reports, we systematically reviewed published episodes to quantify healthcare exposure, antimicrobial selections and susceptibilities, use of source control, and outcomes.

Methods:

In accordance with PRISMA 2020, we searched PubMed, Scopus, and Google Scholar from inception to 10 October 2025 for English-language case reports/series, correspondence, and letters. We extracted demographics, presentation, exposures, microbiology, treatment, source control, and outcomes.

Results:

We included 32 episodes from 29 articles. The mean age was 53.9 years, and 17/32 (53.1%) were female. Healthcare exposure occurred in 30/32 (93.8%) patients, and device- or procedure-related involvement occurred in 22/32 (68.8%) patients. Abdominal pain was reported in 20/32 (62.5%) patients. All cases were culture-confirmed. Source control was performed in 12/32 (37.5%) patients. Clinical improvement occurred in 24/32 (75.0%); relapse occurred in 8/32 (25.0%), with most relapses device-associated; and death occurred in 6/32 (18.8%) cases.

Conclusions:

A. xylosoxidans intra-abdominal infections are uncommon but largely healthcare-associated and often device-related. Because standard empiric regimens frequently lack activity against A. xylosoxidans, clinicians should suspect it when a nonfermenting Gram-negative rod is reported or when patients fail to improve on initial therapy and promptly initiate susceptibility-guided antibiotics with timely source control to reduce relapse and mortality. Standardized reporting of susceptibilities, device management, and outcomes is needed to refine the regimen and duration choices.

Introduction

Achromobacter xylosoxidans is an aerobic, motile, non-fermenting Gram-negative bacillus belonging to the family Alcaligenaceae (formerly classified as Alcaligenes xylosoxidans) ^[1^]. It is ubiquitously found in water and soil and has been isolated from various clinical specimens, including blood, cerebrospinal fluid, urine, respiratory secretions, stool, peritoneal fluid, and wound exudates, especially from hospitalized or immunocompromised patients. A. xylosoxidans is predominantly recognized as an opportunistic nosocomial pathogen that is associated with indwelling devices or moist environments. Historically, it has been frequently misidentified as Pseudomonas aeruginosa in clinical laboratories because of phenotypic similarities; one distinguishing feature is that A. xylosoxidans possesses peritrichous (multiple) flagella, in contrast to the single polar flagellum of Pseudomonas^[1^]. Advances in identification methods (e.g., MALDI-TOF mass spectrometry and genetic sequencing) now facilitate more accurate recognition of this organism, revealing its true involvement in human infections^[2^].

HIGHLIGHTS

• Most intra-abdominal infections due to Achromobacter xylosoxidans were healthcare-associated (93.8%) and frequently device-related (68.8%); the presence of recent procedures or indwelling devices should heighten suspicion.

• Presentation was nonspecific – abdominal pain was most common (62.5%)–so diagnosis typically relies on culture from a sterile/target site.

• Initial empiric regimens often lack activity against A. xylosoxidans, prompting escalation to a reliably active β-lactam (commonly piperacillin/tazobactam or a carbapenem), with step-down only when susceptibilities support it.

• Source control (catheter/stent exchange or drainage) was undertaken in 12/32 (37.5%) and was frequently decisive, particularly in device-associated disease.

• Outcomes were heterogeneous: 75% improved, 25% relapsed (mostly device-linked), and mortality was noted in 18.8% – favor early recognition, susceptibility-guided therapy, and timely source control.

Although A. xylosoxidans is best known for causing bacteremia (often catheter-related) and respiratory infections (especially in patients with cystic fibrosis), it can also cause intra-abdominal infections in certain scenarios. Such cases are rare but increasingly reported, especially in patients undergoing peritoneal dialysis (PD), abdominal surgeries, or biliary interventions^[3^]. Patients with intra-abdominal A. xylosoxidans infections often present with signs and symptoms that are indistinguishable from those caused by more common organisms. Typical manifestations include fever, abdominal pain, localized tenderness, and signs of peritoneal inflammation or sepsis, depending on the nature and severity of the infection. Notably, A. xylosoxidans infections can range from acute, fulminant presentations (e.g., septic shock in cholangitis or peritonitis) to indolent, chronic courses (e.g., subacute abscess formation).

These infections are particularly challenging because of intrinsic multidrug resistance and biofilm formation^[4^]. This systematic review aims to provide a comprehensive synthesis of published cases, focusing on characterizing clinical presentations and diagnostic approaches, quantifying healthcare exposure/device association, summarizing antimicrobial selections/susceptibilities, describing treatments and source-control use, and reporting outcomes to guide clinicians in managing rare but serious infections.

Materials and methods

Literature review

This review comprehensively assesses the existing literature on intra-abdominal infections caused by A. xylosoxidans. This analysis was conducted in accordance with the guidelines for systematic reviews and meta-analyses outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)^[5^] and has been reported in line with the AMSTAR (Assessing the methodological quality of systematic reviews) guidelines. The review synthesized published case reports, case series, correspondence articles, and letters describing intra-abdominal infections caused by A. xylosoxidans in adults. Because the available evidence consisted primarily of descriptive case-level literature and no comparative or interventional analyses were planned, the review was not prospectively registered. This review adheres to the 2025 TITAN Guidelines on the transparent and responsible use of artificial intelligence in scholarly writing and authorship practices^[6^].

We conducted a systematic search of the PubMed, Google Scholar, and Scopus databases for studies published in English. A comprehensive search strategy included the combined use of Medical Subject Headings terms “A. xylosoxidans,” “intra-abdominal infections,” “peritonitis,” “abscesses,” “cholangitis,” and “infections.” The search concepts combined organisms (Achromobacter/Alcaligenes xylosoxidans) with intra-abdominal syndromes (peritonitis, abscesses, cholangitis, pancreatitis) using Boolean operators (e.g., (Achromobacter OR Alcaligenes) AND xylosoxidans AND (peritonitis OR intra-abdominal OR abscess OR cholangitis)). The search covered from database inception through 10 October 2025; the reference lists of the included articles were manually searched.

Inclusion and exclusion criteria

The inclusion criteria for the studies were: (1) English-language publications; (2) adults (≥18 years) with intra-abdominal infection attributed to A. xylosoxidans; (3) case reports, case series, correspondence articles, and letters to the editor; and (4) studies with culture-positive A. xylosoxidans from a sterile/target site (e.g., ascitic/peritoneal fluid, bile, abscess/pus). The exclusion criteria were as follows: (1) insufficient data (e.g., organism not confirmed); (2) pediatric cases; (3) duplicate studies; (4) inaccessible full texts despite efforts to obtain them; and (5) A. xylosoxidans infections without an intra-abdominal source. The reference lists of the included articles were manually screened to ensure comprehensive coverage of the available literature. Data on patient demographics (age and sex), clinical presentation, prior healthcare exposures, antimicrobial resistance patterns, therapeutic interventions, and clinical outcomes were systematically extracted.

Data extraction and statistical analysis

The preliminary title and abstract screening was independently completed by two reviewers. After the initial screening, the full-text review of the screened articles was performed by the same two reviewers. Articles that satisfied all inclusion and exclusion criteria for the full-text review were selected for the final systematic review. A third reviewer performed a full-text review of all the selected articles to eliminate any selection errors.

We extracted episode-level data regarding demographics, presentation, comorbidities, healthcare exposure/device involvement, microbiology, antimicrobial therapy, source control, and outcomes (Table 1). “Replacement” was defined as the exchange or removal and reinsertion of an indwelling device (e.g., PD catheter, biliary stent, or drainage catheter) as part of source control. The aggregate characteristics and overall outcomes are summarized in Table 2. The comorbidities and treatment patterns are presented in Table 3. Reported antimicrobial susceptibility patterns are included in Table 4. Due to heterogeneity in susceptibility testing methods, reporting standards, and incomplete data across case reports, Table 4 represents a qualitative synthesis rather than a pooled quantitative analysis.

Table 1.

Summary of included episodes of intra-abdominal infections caused by Achromobacter xylosoxidans.

#	Author	Age/sex	Chief complaint	Infection type	Comorbidities/risk factors	Microbiology	Antibiotics used (duration if stated)	Source control	Outcome
1.	Tawhwari I et al[3]	64, F	Abdominal pain, nausea	CAPD-associated peritonitis	ESRD on CAPD	Peritoneal fluid culture +	Empiric IV vancomycin 1 g every 5 days /cefepime 1 g every other day → IP meropenem 1 g daily (3 weeks) → repeat hospitalization 12 days after finishing antibiotics for C. difficile followed by peritoneal culture of AX → continued IV meropenem 1 g daily (14 days) + removal of catheter + hemodialysis placement	Yes—catheter exchange/removal	Improved
2.	Tsai SF et al[4]	51, F	Abdominal pain	CAPD-associated peritonitis	T2DM, HTN, hepatitis C, Child-Pugh Class B cirrhosis, 4 episodes of peritonitis	Ascitic fluid culture +	Catheter removal + IV cefazolin and ceftazidime (4d) → ampicillin and sulbactam for (7d) → ciprofloxacin (2d) → cefepime (due to concomitant hospital acquired pneumonia) (7d)	Yes—catheter exchange/removal	Improved
3.	Mohammadi A et al[7]	80, F	Altered mentation, sudden seizure-like movements	CAPD-associated peritonitis	HTN, CVA, ESRD, sick sinus syndrome, outpatient peritoneal AX infection treated with eravacycline 1 week prior	Peritoneal fluid culture +	IV cefepime and metronidazole 2 days → IV meropenem, IV vancomycin, intraperitoneal ceftazidime 1 day → IV meropenem, IV eravacycline, and IP ceftazidime for 5 days → IP ceftazidime and IV eravacycline → relapse IV meropenem 5 days → IP meropenem 3 days → IV meropenem 3 days → 14 days IV ertapenem	No/not stated	Improved
4.	Morrison AJ et al[8]	34, F	Nausea, vomiting, chills, abdominal pain	CAPD-associated peritonitis	HTN, ESRD secondary to glomerulonephritis	Peritoneal fluid culture +	IP tobramycin (20 mg in 1 L) 3 days + IP cephalothin (250 mg in 1 L) for 3 days → 2nd infusion of IP TMP-SMX (80–400 mg in 1 L loading dose → 5 mg-25 mg/L 10 days)	No/not stated	Improved
5.	Tsai MT et al[9]	45, F	Abdominal pain	CAPD-associated peritonitis	ESRD secondary to IgA nephropathy, history of PD infections	Catheter culture +	Oral ciprofloxacin 2 weeks → hospitalized 1 month later, given augmentin for 2 weeks → Tenckhoff catheter replaced + oral 3rd generation cephalosporin → 2 weeks later same issue → empiric cefazolin and ceftazidime 125 mg/L → ampicillin/sulbactam 3 weeks	Yes—catheter exchange/removal	Improved
6.	Tsai JL et al[10]	82, F	Abdominal pain, erythema	CAPD-associated peritonitis	Diabetic nephropathy, ESRD on CAPD	Pus culture +	Oral ciprofloxacin 250 mg q12hr for 2 weeks → relapse 8 weeks later, same treatment	No/not stated	Improved
7.	Haqqie SS et al[11]	45, M	Abdominal cramps	CAPD-associated peritonitis	ESRD secondary to membranoproliferative glomerulonephritis, HTN, failed cadaver renal transplant, secondary hyperthyroidism, previous episode of CAPD peritonitis (coagulase (-) staph) 6 months ago	Peritoneal fluid culture +	One dose of IP vancomycin 2 g followed by IP gentamicin 40 mg daily → recurrent infection → IP gentamicin 8 mg/L + oral ciprofloxacin 500 mg BID → catheter removed → third infection → exploratory laparotomy + piperacillin /tazobactam	Yes—catheter exchange/removal	Improved
8.	Kocak G et al[12]	31, M	Abdominal pain	CAPD-associated peritonitis	Obstructive uropathy for 5 years, ESRD, recurrent UTI	Peritoneal fluid culture +	IP cefazolin and ceftazidime → meropenem for UTI for 3 weeks	No/not stated	Improved
9.	Tang S et al[13]	46, F	Fever, abdominal pain	CAPD-associated peritonitis	Previous episode of peritonitis due to M. tuberculosis, parathyroidectomy secondary to uncontrolled hypercalcemia and renal osteodystrophy, ESRD secondary to IgA nephropathy, and catheter infection by Staphylococcus aureus	Peritoneal fluid culture +	Empiric IP cefazolin and tobramycin → IP ceftazidime + amikacin → Tenckhoff catheter removed + hemodialysis + IV piperacillin /tazobactam for 3 weeks	Yes—catheter exchange/removal	Improved
10.	Tang S et al[13]	35, F	Peritonitis	CAPD-associated peritonitis	ESRD secondary to IgA nephropathy, kidney transplant, chronic allograft rejection, MVP, midbrain infarct	Peritoneal fluid culture +	Empiric IP cefazolin and tobramycin → IP ceftazidime + amikacin → Tenckhoff catheter removed + hemodialysis + IV piperacillin /tazobactam for 3 weeks	Yes—catheter exchange/removal	Improved
11.	Donderski R et al[14]	27, F	Fever, abdominal pain	Postop intra-abdominal abscess	FSGS/ESRD, chronic hepatitis C infection, HTN, reflux esophagitis, and chronic gastritis	Peritoneal fluid culture +	Empiric IP ceftazidime 1 g and cefazolin 1 g → imipenem and cilastatin IV 2 × 0.25 g (2 weeks) → admitted 7 days later for same issue; IP 1 × 1 g ceftazidime and IV 2 × 0.25 g imipenem for 2 weeks → 3rd episode 2 weeks after d/c for same issue (removed catheter and started on hemodialysis	Yes—catheter exchange/removal	Improved
12.	Ledger SG et al[15]	72, F	Cloudy dialysate and tender exit site	Peritonitis	ESRD secondary to diabetic nephropathy, hypertensive nephrosclerosis	Peritoneal fluid culture +	Ciprofloxacin po 500 mg BID → one dose of IP cefazolin 1 g and ceftazidime 1 g → IV imipenem 250 mg q12hr 3 doses → IP Imipenem 1 g q12hr (30 days) + Ciprofloxacin po 500 mg BID for 10 days upon discharge	No/not stated	Improved
13.	El-Shahawy MA et al[16]	52, F	Abdominal pain	Peritonitis	ESRD secondary to diabetic nephropathy, T2DM, diabetic retinopathy, PAD, right BKA, history of cloudy dialysate	Peritoneal fluid culture +	Empiric IP vancomycin 2 g and IV ceftazidime 1 g → ofloxacin (500 mg po daily) + ceftazidime (7 days) + removal of catheter + hemodialysis	Yes—catheter exchange/removal	Improved
14.	Yilmaz G et al[17]	70, M	Jaundice, abdominal pain	ERCP (biliary) associated bacteremia	Pancreatic cancer diagnosis 3 months ago, treated with chemotherapy for one month	Blood culture +	Empiric ceftriaxone (1000 mg q12hr) → IV ciprofloxacin (200 mg q12hr	No/not stated	Improved
15.	Khan M et al[18]	32, M	Epigastric pain, vomiting	Pancreatic Pseudocyst	Smoker	Peritoneal fluid from ERCP culture +	Empiric (Meropenem) → IV injection of meropenem q8hr	No/not stated	Improved
16.	Otta S et al[19]	32, M	Epigastric pain, vomiting	Pancreatitis	HTN, alcohol abuse	Blood culture +	Empiric ciprofloxacin → amikacin and piperacillin /tazobactam	No/not stated	Improved
17.	Eshwara VK et al[20]	42, M	Epigastric pain, vomiting	Intra-abdominal infection	Epilepsy, HTN, lumbosacral disc surgery five years ago	Purulent fluid from ERCP culture +	Empiric (Meropenem) → Cefoperazone-sulbactam (14 days)	No/not stated	Improved
18.	Castellote J et al[21]	54, M	Fever, abdominal pain	Peritonitis	Alcohol abuse, Child-Pugh Class C cirrhosis, recent hospitalization	Ascitic fluid culture +	Piperacillin /tazobactam (4 g q12 hr)	No/not stated	Died
19.	Vu PQ et al[22]	47, F	AMS	Peritonitis	Alcohol use, decompensated liver cirrhosis	Ascitic fluid culture +	IV cefepime	No/not stated	Died
20.	Barakat M et al[23]	60, F	Diarrhea, vomiting	Post-liver transplant biloma with intra-abdominal abscess	T2DM, CKD, liver transplant from liver cirrhosis secondary to hepatitis C (on tacrolimus)	Blood culture +	IV ceftriaxone and metronidazole → discontinued after 48 hr. → stool positive for C. difficile but (-) for toxins → started on vancomycin → continued to deteriorate → meropenem after culture results	No/not stated	Died
21.	Jo IH Ko KS[24]	72, F	Jaundice, recurrent epigastric pain	Cholangitis post-ERCP	No significant history	Blood culture +	Ceftizoxime → piperacillin/tazobactam	No/not stated	Improved
22.	Fujioka M et al[25]	78, M	Fever, abdominal pain	Cholecystitis	Extensive burns with multiple surgeries and bilateral BK amputations; hydrotherapy in shared tub; environmental source identified (bathing mattress)	Bile culture +	Imipenem started → changed to piperacillin/tazobactam (duration not stated)	No/not stated	Improved
23.	Hilscher M et al[26]	62, M	Back pain	Cholangitis	T2DM, necrotizing pancreatitis, Roux-en-Y choledochojejunostomy, cholecystectomy, splenectomy, stent in the biliary tree	Blood culture +	Ertapenem + daptomycin (2 weeks)	No/not stated	Outcome Not Clearly Stated
24.	Alzeer ZA et al[27]	38, F	RUQ pain	Sub diaphragmatic abscess	Prior laparoscopic cholecystectomy 6 years earlier complicated by retroperitoneal abscess (drained twice); appendectomy 8 years earlier; four C-sections (last 4 months prior)	Pus from percutaneous drain culture +	IV antibiotics during admission → discharged on oral antibiotics (duration not stated)	Yes—drainage	Improved
25.	Kawaguchi Y et al[28]	65, M	Femoral, groin pain	Retroperitoneal abscess	No significant history	Urine and pus culture +	Piperacillin/tazobactam for 13 days → levofloxacin for 5 days	No/not stated	Improved
26.	Gupta V et al[29]	65, M	Paraumbilical swelling	Abdominal abscess secondary to hernia repair	HTN, CAD, recent paraumbilical hernia repair	Omental specimen culture +	IV Ceftriaxone (1 g q12hr) for 3 days → levofloxacin po 750 mg for 10 days	No/not stated	Improved
27.	Tripathi N et al[30]	65, M	Fatigue, jaundice, epigastric pain, decreased appetite, weight loss	Peritonitis	Alcohol abuse, HTN, tonsillar adenocarcinoma post-chemo-radiation	Ascitic fluid culture +	Empiric piperacillin /tazobactam → for pancreatitis → levofloxacin + metronidazole D4 → linezolid and doxycycline for pneumonia D6 → D13 meropenem and linezolid → linezolid discontinued D17 → piperacillin /tazobactam and vancomycin D22 for 2 days → empiric cefepime, metronidazole, and vancomycin 4 days → piperacillin /tazobactam D27 for AX infection → continued peritonitis changed to meropenem and vancomycin for 4 days	No/not stated	Died
28.	Dhakshna Murthi M et al[31]	70, F	Myalgias, intermittent giddiness, abdominal pain	Post-op infection of incisional hernia	HTN, T2DM, laparotomy for uterine tumor, meshplasty for incisional hernia	Blood culture +	Empiric piperacillin/tazobactam + amikacin → IV piperacillin /tazobactam and meropenem for 5 days → oral amoxicillin/clavulanate for 5 days after discharge	No/not stated	Outcome not clearly stated
29.	Asano K et al[32]	52, F	Fever	Liver abscess	Cholecystectomy, T2DM	Abscess from right lobectomy culture +	No antibiotics mentioned	Yes—surgical source control	Improved
30.	Asano K et al[32]	57, M	Weight loss	Liver abscess	Cholecystectomy, partial liver resection secondary to liver abscess	Abscess from lobectomy culture +	No antibiotics mentioned, recurrent liver abscess growing AX	Yes—surgical source control	Died
31.	Asano K et al[32]	52, M	Cough, diaphoresis	Liver abscess	Cholecystectomy, partial liver resection secondary to liver abscess	Abscess from lobectomy culture +	No antibiotics mentioned, recurrent liver abscess growing AX	Yes—surgical source control	Died
32.	Srinivas J et al[33]	47, M	Fever, anorexia, abdominal distension, and altered sensorium	Ascites	Alcohol abuse, Child-Pugh Class C cirrhosis with portal HTN	Ascitic fluid culture +	Empiric IV cefotaxime 2 g q8hr → levofloxacin 500 mg + IV albumin for 3 days → discharged on levofloxacin 500 mg po daily for 14 days	No/not stated	Improved

AX, Achromobacter xylosoxidans; BKA, below-knee amputation; CAPD, continuous ambulatory peritoneal dialysis; C. difficile, Clostridium difficile; CVA, cerebrovascular accident; ERCP, endoscopic retrograde cholangiopancreatography; ESRD, end-stage renal disease; FSGS, focal segmental glomerulosclerosis; g, gram; HTN, hypertension; IP, intraperitoneal; IV, intravenous; L, liter; mg, milligram; PD, peritoneal dialysis; PO, oral; T2DM, type 2 diabetes mellitus; TMP-SMX, trimethoprim sulfamethoxazole.

Table 2.

Important characteristics and outcomes noted in intra-abdominal infections caused by Achromobacter xylosoxidans.

Characteristic	Result
Mean age (SD)	53.9
Median age (IQR)	52.0
Females	53.1%
Commonest chief complaint	Abdominal pain (62.5%)
Surgical or interventional source control	37.5%
Positive cultures	100.0%
Clinical improvement/survival	75.0%
Relapse	25.0%
Death	18.8%

IQR, interquartile range; SD, standard deviation.

Values are n/N (%), unless otherwise indicated. “Positive cultures” reflect the inclusion criterion of culture confirmation. “Surgical or interventional source control” includes catheter/stent exchange or removal, percutaneous/operative drainage, or resection.

Table 3.

Comorbidities and treatment patterns noted in intra-abdominal infections caused by Achromobacter xylosoxidans.

Characteristic	Result (%)
Hypertension	34.4
Type 2 diabetes mellitus	18.8
End-stage renal disease	34.4
Most common empiric antibiotics
Piperacillin/tazobactam	12.5
Ceftazidime	28.1
Carbapenem	18.8
No mention	12.5
Most common culture-sensitive Therapy
Carbapenem	18.8
Fluoroquinolone	18.8
Piperacillin/tazobactam	15.6
Ceftazidime	15.6

Values are presented as n (%). “Most common empiric antibiotics” summarizes initial regimens (categories are not mutually exclusive and may not sum to 100%). “Most common culture-sensitive therapy” summarizes agents used as directed therapy when susceptibilities were reported (also not mutually exclusive).

Table 4.

Reported antimicrobial susceptibility patterns of Achromobacter xylosoxidans in intra-abdominal infections.

Antimicrobial agent/class	General pattern across reported cases	Notes
Piperacillin/tazobactam	Frequently reported as active/susceptible	Commonly used as targeted therapy in biliary, postoperative, and some PD-associated infections
Carbapenems (imipenem, meropenem)	Frequently reported as active/susceptible	Often used in severe infection, treatment failure, or resistant isolates
Ceftazidime	Variable but often susceptible	Common empiric or definitive agent in PD-associated peritonitis cases
Fluoroquinolones (ciprofloxacin, levofloxacin)	Variable susceptibility	Used in some definitive or step-down regimens when supported by susceptibilities
Trimethoprim/sulfamethoxazole	Variable susceptibility	Occasionally used as targeted oral therapy when isolate susceptibility was confirmed
Aminoglycosides	Inconsistent activity	Limited by variable susceptibility and toxicity concerns
Ceftriaxone/cefotaxime	Frequently inactive or unreliable	Standard empiric regimens may not provide reliable coverage
Other cephalosporins	Often limited/unreliable activity	Susceptibility varied substantially across reports
Aztreonam	Frequently resistant	Not consistently active in reported cases
Colistin/polymyxins	Rarely reported	Too few data for meaningful conclusions
Tetracycline derivatives (including eravacycline)	Limited case-based evidence	Salvage use reported in refractory PD-associated peritonitis
Amoxicillin/clavulanate	Generally unreliable	Not favored based on intrinsic resistance concerns

PD, peritoneal dialysis

Susceptibility reporting was heterogeneous across included case reports and case series, with variation in testing methods, antimicrobial panels, interpretive breakpoints, and completeness of data. Accordingly, this table provides a qualitative summary of reported patterns rather than pooled quantitative susceptibility estimates.

Quality assessment

The quality of each article was assessed using the Joanna Briggs Institute (JBI) checklist^[34^]. A score of 1 point was assigned to each of the eight separate tools, as per the checklist. Two independent reviewers reviewed each article, and any discrepancies were resolved by a third reviewer.

Unit of analysis

When an article reported more than one independent case, each was treated as a separate case. When a single patient experienced a culture-proven relapse after the initial improvement, the relapse contributed to the relapse outcome but was not counted as a new index case.

Statistical approach

Given the descriptive nature of the available literature and the small number of heterogeneous cases, only descriptive statistics were used. Continuous variables were summarized as means and medians, where appropriate, and categorical variables as counts and percentages. Because all included studies were case reports or small case series, formal meta-analysis and assessment of publication bias were not performed.

Results

Study selection

Database searches identified 319 records from Google Scholar, 102 from PubMed, and 31 from Scopus. After deduplication and screening of titles and abstracts, 36 records were assessed in full, and 29 articles were included in the review. Because two articles reported two and three independent cases, respectively, the final dataset comprised 32 case episodes derived from 29 articles (see PRISMA flow diagram in Fig. 1).

Figure 1.

Flow diagram of the literature search and study selection for the systematic review (PRISMA flowchart).

Study characteristics and quality assessment

All included items were single-patient case reports, correspondence, or letters with adequate clinical and microbiological details (Table 1). Using the JBI case-report checklist (8 items), Reviewer A’s mean score was 7.41, Reviewer B’s mean was 7.50, and the overall mean (episode-level average of both reviewers) was 7.45 (range: 5–8). Distribution: 14/32 (43.8%) scored 8/8 by both reviewers, 10/32 (31.3%) scored 7/8, 7/32 (21.9%) had mixed scores of 7/8 or 8/7, and 1/32 (3.1%) scored 5/8. Overall, 31/32 (96.9%) episodes averaged ≥7/8, indicating moderate-to-high reporting quality.

Patient demographics, exposures, and presentation

Across 32 episodes, the mean age was 53.9 years (median 52), and 53.1% were females (17/32). Healthcare exposure was present in 30/32 (93.8%) patients, with device/procedural involvement in 22/32 (68.8%) patients. Peritoneal-dialysis peritonitis was noted in 13/32 (40.6%) patients, biliary infections in 5/32 (15.6%) (including Endoscopic Retrograde Cholangiopancreatography [ERCP]/stent-associated in 4/32, 12.5%), post-operative/mesh/foreign-body in 5/32 (15.6%), liver abscess was observed in 3/32 (9.4%), spontaneous bacterial peritonitis (SBP)/bacterascites in 3/32 (9.4%), pancreatic collections noted in 2/32 (6.3%), and retroperitoneal abscess in 1/32 (3.1%) patients. Common comorbidities included hypertension in 11/32 (34.4%) patients, end-stage renal disease in 11/32 (34.4%) patients, and type 2 diabetes in 6/32 (18.8%) patients. The most frequent symptom was abdominal pain 20/32 (62.5%). All cases were culture-confirmed (32/32, 100%) from sterile/target sites (blood, peritoneal/ascitic fluid, bile, or pus/abscess).

Microbiology and management

Initial empiric regimens most often included ceftazidime (9/32, 28.1%), carbapenems (6/32, 18.8%), or piperacillin/tazobactam (4/32, 12.5%), and no empiric agents were reported in 4/32 (12.5%). Definitive/active agents, when stated, most commonly included carbapenems (6/32, 18.8%), fluoroquinolones (6/32, 18.8%), piperacillin/tazobactam (5/32, 15.6%), and ceftazidime (5/32, 15.6%). Source control (catheter exchange/removal, drainage, or resection) was performed in 12/32 cases (37.5%).

Outcomes

Clinical improvement/survival occurred in 24/32 (75.0%) episodes. Deaths were reported in 6/32 (18.8%) patients, and the outcome was not clearly stated in 2/32 (6.3%) patients. Relapse of A. xylosoxidans infection was documented in ~25.0% (8/32) of cases, predominantly in device-associated infections (e.g., PD). These outcomes occurred across heterogeneous clinical phenotypes, with PD-associated peritonitis representing the most frequent syndrome, followed by biliary infections, postoperative or mesh-related abscesses, retroperitoneal abscesses, pancreatic collections, and spontaneous bacterial peritonitis/bacterial ascites in cirrhosis.

Discussion

Intra-abdominal infections due to A. xylosoxidans remain uncommon but clinically important, predominantly in patients with recent healthcare exposure or indwelling devices. These infections often present diagnostic challenges owing to their nonspecific clinical manifestations and a low index of suspicion. Moreover, resistance to commonly used empiric antibiotics compounds the complexity of treatment.

In our synthesis of 32 case episodes from 29 articles, patients were middle-aged (mean age of 53.9 years) with a slight female predominance (53.1%). Abdominal pain was the most frequent complaint (62.5%), and diagnoses were laboratory driven; all episodes were culture-confirmed from sterile sites (blood, peritoneal/ascitic fluid, bile, or pus). Outcomes varied by syndrome and host; overall clinical improvement was noted in ~75%, mortality occurred in 6/32 (18.8%) cases, relapse was observed in ~25%, and approximately 37.5% required procedural source control.

PD-associated peritonitis accounted for the largest fraction of episodes and showed a biofilm/device pattern: improvement often followed appropriate antibiotics, but relapse was common unless hardware was addressed^[1,3,4,7–16^]. Multiple reports have described initial responses with subsequent recurrence necessitating Tenckhoff removal or exchange^[1,10,13^], and a contemporary refractory case required eravacycline alongside intraperitoneal and intravenous β-lactams before clinical improvement^[7^]. These observations, together with our ~25% relapse rate concentrated in device-associated disease, support a low threshold for exchanging or removing PD catheters when A. xylosoxidans is identified or when the clinical response to active agents is incomplete.

A. xylosoxidans has also been isolated from pancreatic collections (infected pseudocyst/necrotizing pancreatitis) with good outcomes when carbapenem-based therapy was paired with endoscopic or operative drainage, as indicated^[4,17–20^]. In contrast, the outcomes were poorer in patients with cirrhosis and transplant recipients. Spontaneous bacterial peritonitis (SBP) caused by A. xylosoxidans is associated with high mortality in early and modern reports^[21,22^], and a liver-transplant recipient with biloma and intra-abdominal abscess deteriorated rapidly despite initial regimens until A. xylosoxidans was recognized^[23^]. These higher-risk hosts are vulnerable to empiric mismatches (e.g., ceftriaxone/cefotaxime alone for SBP), reinforcing the need to escalate early to agents with reliable activity against A. xylosoxidans when nosocomial exposure or lack of response raises concerns.

Biliary infections illustrate the principle that drainage is decisive^[24–26^]. A. xylosoxidans has also been cultured from bile in a burn-unit patient, in whom environmental sampling implicated contaminated water-contact equipment^[25^], emphasizing procedural and environmental links. Antibiotics alone frequently underperform when biliary drainage is inadequate, and restoring flow is the turning point.

Postoperative and foreign-body-related infections further highlight the need to search for retained material^[27–33^]. An example is the diagnosis of a subdiaphragmatic abscess in a patient years after cholecystectomy due to a dropped gallstone, which resolved only after drainage and antibiotics^[27^]. A. xylosoxidans presented as a retroperitoneal abscess masquerading as femoral pain in a patient, delaying diagnosis until urine/pus cultures directed therapy with drainage^[28^] and as a mesh-related infection requiring combined surgical and antimicrobial management^[29^]. In these settings, re-imaging and definitive source control (drainage, debridement, and foreign body removal) frequently mark the point of recovery.

Therapeutically, the pattern across phenotypes is consistent: empiric mismatch is common, with early cephalosporins or fluoroquinolones frequently failing until escalation to piperacillin/tazobactam or a carbapenem; trimethoprim/sulfamethoxazole or a fluoroquinolone has been used variably for step-down when supported by susceptibilities, and eravacycline appears as salvage for refractory PD peritonitis^[4,7,9,23^]. Given the intrinsic multidrug resistance and biofilm-forming capacity of A. xylosoxidans, therapy should be susceptibility-guided, paired with source control, and followed by close monitoring to detect relapse. To improve clinical interpretability, we summarized the reported susceptibility patterns qualitatively in Table 4; however, these data should be interpreted cautiously because susceptibility testing and reporting were not standardized across cases.

Our systematic review has several limitations. First, the evidence base consisted almost entirely of case reports and small case series, making the review inherently vulnerable to publication and reporting bias; unusual, severe, refractory, or procedurally complex cases are more likely to be published than routine or rapidly resolving infections. Because of the descriptive and heterogeneous nature of these reports, formal assessment of publication bias using standard quantitative methods was not feasible. Second, the number of included episodes was small, and clinical phenotypes were heterogeneous, spanning PD-associated peritonitis, biliary infection, postoperative and mesh-related infection, liver abscess, pancreatic infection, retroperitoneal abscess, and spontaneous bacterial peritonitis or bacterascites. This heterogeneity precluded meta-analysis and limited meaningful subgroup comparisons. Third, microbiologic methods and susceptibility reporting were inconsistent across reports, with variation in organism identification techniques, antimicrobial panels tested, interpretive criteria, and completeness of susceptibility data. As a result, our summary of antimicrobial susceptibility patterns is qualitative rather than quantitative. Fourth, details regarding healthcare exposure, device status, timing of procedures, and source-control interventions were variably reported, and some classifications required reasonable inference from the published narrative. Fifth, follow-up duration and outcome definitions were inconsistent, which may have led to under-recognition of relapse. Sixth, given observational, case-level data, confounding is substantial, and causal attribution separating the effects of specific antibiotics from the timing and type of source control is not possible. Finally, the review was limited to English-language publications, and inaccessible full texts were excluded, so additional relevant cases may have been missed.

Recent studies have highlighted the emerging role of artificial intelligence tools, including large language models, in assisting with literature synthesis and medical research analysis. However, their use requires careful validation to ensure scientific accuracy and transparency. Future systematic reviews may incorporate such tools cautiously to enhance the efficiency of literature screening ^[35^].

Clinically, A. xylosoxidans should be considered in healthcare-associated intra-abdominal infections, especially PD peritonitis, post-ERCP cholangitis, and postoperative abscesses when a nonfermenting Gram-negative rod grows or when standard empiric therapy underperforms. Early, comprehensive culturing, proactive source control (catheter exchange/removal, drainage, stent optimization), and timely escalation to agents active against A. xylosoxidans can reduce morbidity and likely mitigate the observed relapse signal. Future multicenter efforts should quantify susceptibility distributions, compare outcomes by regimen and timing of device intervention, and clarify the optimal treatment duration by syndrome and source-control status.

Conclusion

A. xylosoxidans is an uncommon but clinically important cause of intra-abdominal infections that are largely healthcare-associated and often device-related. In our synthesis, 93.8% of the episodes had recent healthcare exposure, 68.8% involved a device or recent procedure, and 37.5% required source control. These findings underscore the importance of early recognition when a nonfermenting Gram-negative rod is isolated or when patients fail to improve on initial therapy, and of promptly administering susceptibility-guided antibiotics paired with timely device intervention or drainage. Future multicenter studies should define optimal initial antimicrobial regimens, indications, and timing for device removal/exchange, and the treatment duration by syndrome and source-control status, while monitoring evolving resistance.

Ethical approval

It was not required, as this systematic review used data extracted from previously published reports.

Consent

Not required for this review article. All patient information was previously published by the original authors; no new patient data or images were collected.

Sources of funding

No funding was needed for this review article.

Author contributions

All authors have contributed significantly to the preparation of the manuscript. M.T. has primarily conceptualized, written, and edited the manuscript. H.P. and K.P. helped gather and compile the literature and write the manuscript. S.B. and S.P. have provided expert advice and edited the final draft.

Conflicts of interest disclosure

None of the authors has any conflicts of interest to disclose.

Research registration unique identifying number (UIN)

Not applicable.

Guarantor

Mrudula Thiriveedi.

Provenance and peer review

The paper was not invited and was not externally peer-reviewed.

Data availability statement

Not applicable, since this is a review article. None of the contents of the article are derived from any publicly available dataset.

Assistance with the study

None.