Catheter-related Chryseobacterium meningosepticum bacteraemia in a haemodialysis patient.

Sir,

Chryseobacterium meningosepticum (C. meningosepticum), an unusual opportunistic pathogen resistant to multiple antimicrobial agents, was rarely reported to be a cause of bacteraemia in haemodialysis patients.

A 77-year-old female with end-stage renal disease was admitted with fever, chills and tenderness on the insertion site of the femoral double-lumen catheter 2 weeks after the start of haemodialysis. Her body temperature was 38.4°C. Erythema and swelling were present around the exit site of the double-lumen catheter. Laboratory evaluation revealed a haemoglobin of 7.6 g/dL and a C-reactive protein of 7.3 mg/dL. A provisional diagnosis of catheter-related bacteraemia was made. The double-lumen vein catheter was removed along with empiric antimicrobial agents with intravenous vancomycin (2 g/week) plus oral rifampin (450 mg/day). Blood cultures grew C. meningosepticum that was resistant to gentamicin, amikacin and all cephalosporins, but only susceptible to ciprofloxacin and vancomycin. Cultures of the exit site and the tip of catheter also grew C. meningosepticum. Despite 1-week antibiotic therapy, blood cultures still grew the same pathogen. At this time, an echocardiogram was normal. The addition of oral ciprofloxacin (250 mg q12 h) to vancomycin for another 2 weeks achieved uneventful recovery without subsequent growth of this organism. Cultures for tap water and dialysate were also negative for this pathogen.

Chryseobacterium spp. are of low virulence but give rise to severe infections in neonate and immunocompromised hosts. C. meningosepticum was the most common species of human pathogens. In neonates, C. meningosepticum meningitis is the most common infection, whereas pneumonia and sepsis were the most common infections in adults with impaired immunity [1]. Patients with uraemia are at a risk for C. meningosepticum infection due to their compromised T- and B-cell immunity. To date, there were only few reports regarding C. meningosepticum infections in uraemic patients on dialysis (Table 1) [2-5]. Among 42 episodes in 41 dialysis patients, a majority (37/42, 88%) of episodes were related to peritoneal dialysis (PD) catheter peritonitis and a minority (5/42, 12%) of episodes had bacteraemia in patients on haemodialysis. Initial antibiotics to eradicate C. meningosepticum infections were usually inappropriate, leading to the necessity of removal of the catheter in most patients. Four (4/41, 10%) patients died from C. meningosepticum infection. In C. meningosepticum bacteraemia, the exact port of entry was unknown in three episodes. C. meningosepticum was isolated from sink water in only one episode. Although C. meningosepticum was not identified in tap, tank and dialysis water, in our patient it was also isolated from the exit site and the tip of the double-lumen catheter, suggesting that the port of entry be the disruption of skin integrity by internal placement of the catheter. Our case is the first report of C. meningosepticum bacteraemia associated with catheter-related infection in a haemodialysis patient.

Table 1

Demographic data of the reported patients on dialysis with Chryseobacterium meningosepticum infection

	Gender/	Dialysis	Access for	Source of		Initial
Reference	age	modality	dialysis	infection	Consequence	antibiotics	Outcome
[2]	F/33	CAPDa	Tenckhoff	Dialysate	Peritonitis	Not respond	Not remove access,
			catheter	effluent		(TOB + VAN)	survival
[3]	F/76	CAPD	Tenckhoff	Dialysate effluent	Peritonitis;	Not respond	Remove access,
			catheter	Blood	bacteraemia	(CTZ + GM + VAN)	died
[3]	UA/14	CAPD	Tenckhoff	Blood	Sepsis	Not respond	Remove access,
			catheter			(NAF + GM)	died
[3]	F/63	CAPD	Tenckhoff	Dialysate	Peritonitis	Not respond	Remove access,
			catheter	effluent		(AZT+ PIP)	survival
[3]	F/45	CAPD	Tenckhoff	Dialysate	Peritonitis	Not respond	Not remove access,
			catheter	effluent		(IMI and TOB)	survival
[4]	M/54	CAPD	Tenckhoff	Dialysate	Peritonitis	Not respond	Remove access,
			catheter	effluent		(CZL + GM)	survival
[2]	33 cases	CAPD	Tenckhoff	Dialysate	Peritonitis	NA	Remove access:
		(30 episodes)	catheter	effluent	bacteraemia		NA 1 died, 31
		HDb (4 episodes)	NA	Blood			survival.
[2]	M/74	HD	Arteriovenous	Blood	Bacteraemia;	Not respond	Remove access,
			graft		purulent	(MER)	died
					pericarditis
[5]	M/78	CAPD	Tenckhoff	Dialysate	Peritonitis	Respond	Not remove access,
			catheter	effluent		(CIP + RIF)	survival
Our case	F/77	HD	Femoral vein	Tip of the	Bacteraemia	Not respond	Remove access,
			catheter	catheter		(VAN + RIF)	survival

aCAPD; continuous ambulatory peritoneal dialysis.

bHD: haemodialysis.

NA: not available; TOB: tobramycin; VAN: vancomycin; CTZ: ceftazidime; NAF: nafcillin; AZT: aztreonam; PIP: piperacillin; IMI: imipenem; CZL: cefazolin; GM: gentamicin; MER: meropenem; RIF: rifampin; CIP: ciprofloxacin.

Although vancomycin has been previously recommended as the drug of choice for C. meningosepticum infection, recent reports and our case revealed that C. meningosepticum infection failed to respond to vancomycin administration alone [6]. Vancomycin should not be used alone to treat C. meningosepticum infections, especially associated with bacteraemia [6], as shown in the patient.

In conclusion, C. meningosepticum should be considered as a causative pathogen of gram-negative bacilli catheter-related bacteremia in haemodialysis patients. Early recognition of this pathogen with appropriate antimicrobial agent administration will avoid the loss of the catheter and even mortality.

Conflict of interest statement. None declared.