achromobacter xylosoxidans , formerly called alcaligenes xylosoxidans , is an aerobic , non - fermenting , gram - negative bacilli with low virulence .
it was first seen in 1971 by yabuuchi and ohyama in a patient with chronic , inflammatory otitis media . due to its ability to easily oxidize xylose ,
it is primarily found in contaminated soil or water , but it is rare in humans .
it is known to infect immunosuppressed patients , including those with tumors , blood diseases , hypogammaglobulinemia , or acquired immune deficiency syndrome ( aids ) , or those who have undergone organ transplant .
the authors experienced a case of septic shock caused by a. xylosoxidans in an immunocompetent woman with no underlying disease who received extracorporeal shock wave lithotripsy ( eswl ) .
a 52-year - old female patient was admitted to the hospital with colicky , left flank pain .
the patient had no medical history of chronic or immunodeficiency diseases , nor any previous history of urolithiasis or urinary tract infections . on admission , vital signs were stable ; blood pressure was 110/70 mmhg , respiratory rate was 20/min , pulse rate was 69/min , and temperature was 37.0. the patient complained of left flank pain without other urinary symptoms
a complete blood cell count showed white blood cells ( wbcs ) were 9,970/mm ( neutrophils , 84.4% ; lymphocytes , 6.4% ) , hemoglobin was 10.6 g / dl , and platelet count was 142,000/mm . the c - reactive protein ( crp ) was 57.5 mg / dl .
biochemical tests showed blood urea nitrogen ( bun ) was 19 mg / dl , creatinine was 0.8 mg / dl , total protein was 6.5 g / dl , albumin was 3.2 g / dl , total bilirubin was 2.2 mg / dl , aspartate aminotransferase was 34
there were no wbcs in the urinalysis , but red blood cells were over 100 per high - power field ( rbc / hpf ) .
the cause of pain was a urinary stone in the left ureter , noted through ultrasound . on the 3rd and 4th days after admission , the patient underwent eswl , receiving a total of 8,000 shocks .
three days later , the patient 's body temperature rose to 39.9. on the 7th day , her blood pressure fell to 70/50 mmhg , heart rate was 125/min , respiratory rate was 26/min , and body temperature was 39.0. oxygen saturation was 80% on room air .
the patient was moved to the intensive care unit and started on mechanical ventilation and shock management .
wbcs were 18,400/mm ( neutrophils , 90.4% ; lymphocytes , 5.5% ) , hemoglobin was 11 g / dl , platelet count was 92,000/mm , and crp was 240 mg / dl .
cefepime ( 2 g intravenously every 12 hours ) and vancomycin ( 1 g intravenously every 24 hours ) were administered empirically .
the urine cultures were negative but two sets of blood cultures were positive for gram - negative bacilli , which was identified as achromobacter xylosoxidans ( bactec plus aerobic / f culture vials ; becton dickinson and company , franklin lakes , new jersey , united states ) .
the minimum inhibitory concentrations g / ml ) ( bactec fx ; becton dickinson and company ) were as follows : imipenem / cilastatin , 4 ; meropenem , 4 ; piperacillin - tazobactam , 8 ; ampicillin , 16 ; ciprofloxacin , 2 ; amikacin , 32 ; aztreonam , 16 ; and cefepime , 16 .
a. xylosoxidans was resistant to cefepime ; hence , antibiotics were changed to imipenem ( 500 mg intravenously every 12 hours ) . on the 14th day , blood cultures no longer revealed a. xylosoxidans , but the patient 's renal function worsened , requiring continuous renal replacement therapy .
burkholderia cepacia was isolated from one set of blood cultures on the 16th day ; it was susceptible to imipenem / cilastatin .
we removed the central venous catheter to culture for b. cepacia that might have infected the catheter . a tip culture and repeated blood cultures were negative after three days .
on the 21st day , the patient had respiratory failure with bilateral opacities on chest imaging . on the 29th day after admission , she passed away from septic shock and multiple organ failure .
primers of 515fpl ( tgccagcagccgcggtaa ) and 13b ( aggcccgggaacgtattcac ) were used for 16s rrna gene amplification .
a. xylosoxidans is an aerobic , non - fermenting , gram - negative bacilli with low virulence .
infections occur mostly in immunocompromised patients , including those with tumors , blood diseases , hypogammaglobulinemia , aids , diabetes , or late - stage kidney failure , and those who have undergone organ transplants . for cases that progress to bacteremia , it is most often because of an intravenous catheter infection .
a total 224 cases of bacteremia were reported : 74 in neonates and 150 in adults .
the most common cause was catheter- related infection ( 78 cases , 52% in adults ) .
pneumonia was the second most common source ( 12 cases , 8% in adults ) .
a. xylosoxidans typically causes otitis media , skin infections , intravenous catheter infections , and surgical - site infections .
the frequency of urinary tract infection by a. xylosoxidans was 0.04% ( proportion of positive urine cultures ) in a medical center in spain .
urinary tract infection due to a. xylosoxidans often develops from the pathogenic bacteria traveling from the intestines to the ureters and bladder . while it has been reported that a. xylosoxidans causes infections in immunocompromised patients and those with urological abnormalities , the patient in this case had no such tendencies .
the patient in this case had a negative blood culture , but the strains were cultured after the symptoms occurred . according to existing reports , a. xylosoxidans has a high resistance against antibiotics , making treatment difficult .
it is sensitive to imipenem , piperacillin - tazobactam , ceftazidime , and trimethoprim - sulfamethoxazole .
resistance was found in second- or third - generation cephalosporins except ceftazidime and fluoroquinolones . in this case
, it was sensitive to imipenem , meropenem , trimethoprim - sulfamethoxazole , piperacillin - tazobactam , and ceftazidime , and resistant to ampicillin , ciprofloxacin , amikacin , cefotetan , ceftriaxone , aztreonam , and cefepime , showing similar results to existing reports .
attempts have been made to combine two or more drugs for treatment , such as by combining gentamicin with piperacillin , doxycycline with azithromycin , or trimethoprim - sulfamethoxazole with azithromycin .
these combinations have been effective in reducing resistance and increasing the efficacy of treatment . in conclusion
, a. xylosoxidans can cause infection in immunocompromised patients , while infection in immunocompetent hosts is rare .
however , we have observed such a case in a patient who had normal immune function , and report the findings of this case along with a literature review .
 achromobacter xylosoxidans can cause various types of infections , but its infection in humans is rare . 
 a. xylosoxidans has been reported as a rare etiological agent of infections including primary bacteremia , catheter - related bloodstream infection , endocarditis , otitis , and pneumonia , particularly in immunocompromised hosts . 
 we encountered a case of septic shock caused by a. xylosoxidans in a 52-year - old , immunocompetent woman with no underlying disease , who received extracorporeal shock wave lithotripsy to remove a left upper ureteral stone . 
 she was treated with antibiotics to which the organism was susceptible but died as a result of septic shock . 
Introduction
Case Report
Discussion