Vancomycin reconsidered for peritoneal dialysis
October 1, 1997 5 minutes read
Vancomycin reconsidered for peritoneal dialysis
Drug options are limited
Peritoneal dialysis patients are often prone to staphylococcal infections, and vancomycin is one of the traditional first-line treatments of choice because of its efficacy and ease of administration.
That widely accepted clinical approach resulted in the first confirmed infection with vancomycin intermediate-resistant Staphylococcus aureus (VISA) in the United States, but there may have been few options to prevent VISA from arising in that case or others that may follow, clinicians report.1
"In the setting of renal failure, whether hemo dialysis or peritoneal dialysis, staphylococcal infections are relatively common and vancomycin is so easy to use," says William Schaffner, MD, professor of infectious diseases and chairman of the department of preventive medicine at the University of Vanderbilt School of Medicine in Nashville. Vancomycin can be administered in a single dose that lasts for days, particularly easing administration in home care patients. That was the situation that led to the first U.S. VISA case.
"It’s a drug made’ for the renal failure patient. It is convenience personified and today it is also inexpensive," he says. "So it is entirely logical that nephrologists will use vancomycin. But it is important to note that in these circumstances the use of vancomycin is often very appropriate."
Indeed, if the infecting agent is methicillin-resistant S. aureus (MRSA), treatment options other than vancomycin are limited. Such was the case with the patient in Michigan, who developed VISA infection after prolonged intermittent treatment with vancomycin for peritonitis caused by MRSA. There were initial questions raised about the prolonged administration of vancomycin in the case, in part because there was a typographical error in the date reported by the Centers for Disease Control and Prevention.1 Rather than beginning in January 1996, the patient received vancomycin intermittently from January 1997 to June of 1997, the CDC clarified.2 Thus, the actual duration of intermittent vancomycin exposure leading to VISA was considerably shorter, making the case even less of a clinical anomaly than it first appeared and raising concerns that similar cases may appear.
The first U.S. VISA strain was susceptible to rifampin, chloramphenicol, trimethoprim- sulfamethoxazole, and tetracycline. While certainly a better scenario than a VISA strain impervious to other antimicrobials, the treatment options are not as favorable as the susceptibility pattern may suggest, Schaffner warns. Rifampin, for example, should be used only in combination with other drugs for such infections, and tetracycline may actually worsen the course of staph infections even though the organism is susceptible, he emphasizes.
"We would never use tetracycline to treat someone with staphylococcal infection," he says. "These [four] are not great drugs. And you run into all kinds of questions about dosing intervals, which would make the actual administration of these drugs much more complicated and expensive than the use of vancomycin."
Peritonitis implicated again
The first U.S. VISA case occurred in a patient treated with vancomycin for MRSA peritonitis. That was the clinical scenario predicted by Japanese VISA researcher Keiichi Hiramatsu, MD, PhD, who uncovered the first VISA strain in Japan. (See Hospital Infection Control, August 1997, pp. 113-118.)
"It kind of hearkens back to past history. If you look at the first strain of coagulase-negative staphylococci with resistance to vancomycin, it was in a peritoneal dialysis patient," says William Jarvis, MD, acting director of the CDC hospital infections program. "Those with peritoneal dialysis are very commonly colonized with staphylococci, very commonly colonized with MRSA, and therefore are at great risk both because of their renal failure and the selection of antimicrobials that the nephrologists commonly use. The fact that they are colonized with MRSA leads them to receive multiple courses of vancomycin."
Such peritonitis infections in peritoneal dialysis patients may become recurrent, with the risk of subsequent infection increasing in patients who have had one previously.3 Bacterial contamination may come from patients’ own skin flora if they handle their vascular access site, and some studies indicate mupirocin can effectively reduce such self-infections by reducing staph carriage in the nose.4
"There have been a number of studies in hemo dialysis patients, and I suspect the same occurs in peritoneal dialysis patients, that the site around either the vascular access or the peritoneal catheter becomes colonized with S. aureus or MRSA, depending on what the patient is colonized with in the nares or hands," Jarvis says. "That is the opportunity for introduction into the catheter."
According to one recently published study on the issue, a combination of vancomycin and aminoglycosides has also been a common initial empiric therapy for peritonitis to cover the most frequently encountered infectious agents.5 The authors advise dropping this approach to prevent the emergence of resistance pathogens, recommending instead a combination of cefazolin and netilmicin to avoid frequent use of vancomycin.
"For the last 20 years [we] have used vancomycin as a first-line drug for peritonitis," says Friedrich K. Port, MD, professor of medicine at the University of Michigan in Ann Arbor and co-director of the U.S. Renal Data System in Bethesda, MD. "But there has been a concern about vancomycin-resistant staph, so the first line of treatment is changing in peritoneal dialysis."
Likewise, clinicians who treat peritoneal dialysis patients are currently pursuing other antimicrobial options for peritonitis staph infections, and they may switch to other alternatives if the infecting strain is methicillin-sensitive S. aureus (MSSA).
"I think one of the [areas] where we can cut back vancomycin use is after the sensitivities come back," says Timothy Leach, MD, MPH, chief of infection control at the VA Medical Center, East Orange, NJ. "We find that once a staph isolate returns methicillin-sensitive, people are still using vancomycin. When I do consults and one of the dialysis patients gets admitted [with] a methicillin-sensitive staph bacteremia, [we] switch him over to a beta-lactam instead of vancomycin. Beta-lactams are considered the drug of choice for sensitive organisms. You should use oxacillin or nafcillin."
References
1. Centers for Disease Control and Prevention. Staphylococcus aureus with reduced susceptibility to vancomycin United States, 1997. MMWR 1997; 46:765-766.
2. Centers for Disease Control and Prevention. Update: Staphylococcus aureus with reduced susceptibility to vancomycin United States, 1997. MMWR 1997; 46: 813-814.
3. Port FK, Held PJ, Nolph KD, et al. Risk of peritonitis and technique failure by CAPD connection technique: A national study. Kidney Int 1992; 42:967-974.
4. Boelaert JR. Staphylococcus aureus infection in hemodi alysis patients. Mupirocin as a topical strategy against nasal carriage: A review. J Chemother 1994; VI:(Sup No. 2)19-24.
5. Gucek A, Bren AF, Hergouth V, et al. Cefazolin and netilmicin versus vancomycin and ceftazidime in the treatment of CAPD peritonitis. Advance Perit Dial 1997; 13:218-220.
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