K M Bettin

Treatment of Asymptomatic Clostridium difficile Carriers (Fecal Excretors) with Vancomycin or Metronidazole: A Randomized, Placebo-controlled Trial

OBJECTIVE To compare the efficacy of vancomycin and metronidazole for eradication of asymptomatic Clostridium difficile fecal excretion as a means of controlling nosocomial outbreaks of C. difficile diarrhea. DESIGN Randomized, placebo-controlled, non-blinded trial. SETTING Six hundred-bed regional referral Veterans Affairs Medical Center. PATIENTS Thirty patients excreting C. difficile without diarrhea or abdominal symptoms. INTERVENTIONS All patients were randomized to receive 10 days of oral vancomycin, 125 mg four times daily; metronidazole, 500 mg twice daily; or placebo, three times daily. MEASUREMENTS Stool cultures were obtained during treatment and for 2 months after treatment. All C. difficile isolates were typed by restriction endonuclease analysis (REA). RESULTS Clostridium difficile organisms were not detected during and immediately after treatment in 9 of 10 patients treated with vancomycin compared with 3 of 10 patients treated with metronidazole (P = 0.02) and 2 of 10 patients in the placebo group (P = 0.005). The fecal vancomycin concentration was 1406 +/- 1164 micrograms/g feces, but metronidazole was not detectable in 9 of 10 patients. Eight of the nine evaluable patients who had negative stool cultures after treatment with vancomycin began to excrete C. difficile again 20 +/- 8 days after completing treatment. Three of these patients received additional antibiotics before C. difficile excretion recurred, and five acquired new C. difficile REA strains. Four of six patients who received only vancomycin before C. difficile excretion recurred were culture-positive at the end of the study compared with one of nine patients who received only placebo (P = 0.047). CONCLUSIONS Asymptomatic fecal excretion of C. difficile is transient in most patients, and treatment with metronidazole is not effective. Although treatment with vancomycin is temporarily effective, it is associated with a significantly higher rate of C. difficile carriage 2 months after treatment and is not recommended.

Decrease in nosocomial Clostridium difficile-associated diarrhea by restricting clindamycin use.

The spectrum of Clostridium difficile infection ranges from asymptomatic carriage to self-limited diarrhea, pseudomembranous colitis, toxic megacolon, and colonic perforation. Symptomatic infections cause substantial nosocomial morbidity and mortality. Infections often extend hospital stays and add an additional

Molecular epidemiology of Clostridium difficile over the course of 10 years in a tertiary care hospital.

2000 to

Effect of antipyretics on group A streptococcal pyrogenic exotoxin fever production and ability to enhance lethal endotoxin shock.

5000 per episode to costs of health care; in addition, patients commonly relapse [1]. Certain antimicrobial agents (ampicillin, cephalosporins, and clindamycin) particularly predispose patients to the development of C. difficile infection, but virtually every antimicrobial agent has been implicated. Outbreaks of C. difficile diarrhea are associated with the use of specific antimicrobial agents [2-5]. However, when epidemics occur, it is difficult to determine which, if any, control measures have been effective, particularly those directed at control of antimicrobial agent use. Beginning in 1990, an outbreak of C. difficile diarrhea was identified at the Veterans Affairs Medical Center in Tucson, Arizona. The epidemic was eventually terminated after identifying an association of C. difficile infection with clindamycin use and after instituting clindamycin restriction. In this report, we describe the outbreak, identify a predominant clindamycin-resistant strain of C. difficile by restriction endonuclease analysis, document the association of illness with clindamycin use, and show a decreased frequency of clinical cases and the epidemic strain after clindamycin restriction. Methods The Veterans Affairs Medical Center where the epidemic occurred is a Deans Hospital affiliate of the University of Arizona. Hospital discharges and daily census figures showed no significant differences for the 5 years before and during the outbreak; they average 6619 384 patient admissions per year and a census of 168 patients per day. The infection control program is administered by two nurse specialists under the supervision of an infectious diseases physician. The frequency of C. difficileassociated diarrhea has been monitored since 1986 by continuous review of microbiology reports of stool specimens submitted for C. difficile culture or toxin assay. Antibiotic use is restricted for most staff physicians and housestaff to a hospital formulary, and nonformulary antimicrobial agents are only available with approval from an infectious diseases physician. For at least the past 15 years, the formulary has included clindamycin (Cleocin; Upjohn Company, Kalamazoo, Michigan) and has excluded oral vancomycin. Stool specimens from patients with diarrhea who are suspected by their primary care physicians of having colitis were tested for C. difficile. All specimens were tested for cytotoxin by cell culture assay [5] before December 1991 and by latex agglutination [5, 6] thereafter. All specimens tested for cytotoxin and all specimens with a positive latex test result were cultured on cycloserine-mannitol blood agar to isolate C. difficile [7]. For purposes of case definition, all patients who had diarrhea in association with a positive assay for C. difficile-stool cytotoxin or for latex agglutination and who had recent antibiotic therapy (within 60 days) were considered to have C. difficile infection. Diarrhea was defined as 4 or more loose or unformed stools in a 24- to 36-hour period; all specimens submitted to the laboratory were tested. Typing of C. difficile organisms was done on all available unique isolates by restriction of total organism DNA with Hind III restriction endonuclease followed by agarose gel electrophoresis, as previously described [8]. Organism groups and types were determined from comparison with a library of more than 250 types [8]. Clindamycin susceptibility was determined for selected isolates of C. difficile using a microdilution method in Wilkins-Chalgren broth. Clindamycin dilutions were 0.125, 1.0, and 4.0 g/mL. Plates were incubated for 48 hours in an anaerobic glove box. The organism was considered resistant to clindamycin if the minimal inhibitory concentration (MIC) was greater than 4.0 g/mL. Susceptibility to imipenem, penicillin G, amoxicillin-clavulanic acid, ticarcillin-clavulanic acid, metronidazole, and ciprofloxacin were also tested by the same microdilution method. To test for the significance of differences, we used the Fisher exact test for categorical variables and the Mann-Whitney U test for continuous variables. To test for the significance of associations, we used the Dunnett multiple range test [9]. Results Description of the Outbreak In July 1990, 8 patients who had C. difficile infection (15.8 infections per 1000 discharges) were identified at our center (Figure 1). For the previous 33 months, the average monthly incidence (mean SD) had been 1.5 1.1 infections (2.6 infections per 1000 discharges) diagnosed from a mean of 15 stool specimens per month submitted for toxin assay (10% of submitted specimens positive per month). Through July 1991, the incidence of new patients was fivefold higher than this norm, averaging 7.7 infections per month (a total of 101 patients), with all but 1 of these months exceeding the 95% surveillance threshold (4 or more patients per month, normal mean + 2 SD). The mean number of unique patient specimens submitted increased to 36 per month, of which 28% were positive for toxin during this period. Of toxin-positive specimens, 71% and 65% were culture positive before and during the epidemic, respectively. Both the group of 439 isolates tested before the epidemic and the 334 isolates tested during the epidemic that were toxin negative yielded C. difficile in culture 5% of the time. Figure 1. Number of cases of Clostridium difficile -associated diarrhea detected each month before and after clindamycin restriction. The clinical symptoms for approximately 90% of the patients were abrupt onset of abdominal distention, cramping, and profuse diarrhea. Clostridium difficile infection resulted in intestinal infarction and eventual death of one patient. In most patients, diarrhea did not begin to resolve until after institution of specific treatment with either metronidazole or oral vancomycin. The epidemic was recognized within 1 month of its inception, and several attempts at control were instituted, including hospital staff education, increased use of gloves by nursing staff when assisting patients, and improvement of environmental hygiene. Educational efforts began in early August 1990 and were carried out through the remaining calendar year. The medical center staff who participated in the educational process included attending physicians, housestaff, nursing, and housekeeping personnel. The objectives of the educational programs included a review of the epidemiology, transmission, and clinical presentation of C. difficile. Emphasis was placed on prevention of C. difficile transmission through hand washing, glove use, timely changing of gloves, and increased availability of gloves. In addition, routine environmental sanitation practices were reviewed for thoroughness, with emphasis placed on patient-related items, such as bedside commodes and bathrooms. None of these efforts appeared to alter the frequency of the new cases. Organism typing by restriction endonuclease analysis was carried out on isolates of C. difficile from 10 patients diagnosed in November and December of 1990 and from 48 other patients diagnosed from January through July of 1991. Seventeen restriction endonuclease analysis patterns were identified, indicating a high degree of polymorphism. However, isolates from 34 (59%) of the patients had an identical restriction endonuclease analysis pattern, type J7 (Figure 2), with only 1 to 5 isolates representing each of the other types. Figure 2. Restriction endonuclease analysis patterns of Clostridium difficile strains isolated during and after the epidemic. The susceptibility to clindamycin of six strains of C. difficile, isolated from patients from Tucson (Veterans Affairs Medical Center), is shown in Table 1. All six isolates were susceptible to penicillin G, imipenem, amoxicillin-clavulanate, ticarcillin-clavulanate, and metronidazole and were resistant to ciprofloxacin (data not shown). Both J7 type strains were resistant to clindamycin. Table 1. Clindamycin Susceptibility of Six Outbreak Isolates of Various Restriction Endonuclease Analysis Types Analysis of Clindamycin Use Associated with Clostridium difficile Infections Several lines of evidence linked clindamycin use with the epidemic. First, before the onset of the epidemic, clindamycin use markedly increased. For the years 1986 through 1989, the average amount of clindamycin dispensed was 315 grams per month. In 1990, clindamycin use was 489 grams per month, an increase of 41% compared with the previous year (P < 0.001). Second, in a survey conducted by the College of American Pathologists in 1989 of 220 teaching facilities, our center ranked in the 99th percentile for clindamycin use [10]. This level of use was higher than for any other antimicrobial agent on our formulary (Table 2). Third, administration of clindamycin was significantly more likely to be associated with C. difficile infection than was administration of other commonly used antimicrobial agents (Table 2). Infected patients were three to nine times as likely to have received clindamycin compared with another antimicrobial agent. The association of C. difficile infection with clindamycin was greater than for each of the other antimicrobial agents (all P < 0.05 using the Dunnett multiple range test [9] for clindamycin compared with various antimicrobial agents). Table 2. Relation of Antibiotic Use and Clostridium difficileassociated Diarrhea The association of increased clindamycin use with the increased frequency of C. difficile infection was examined further by analyzing the temporal relation (Figure 3). For the 19 months ending in July 1991, a positive relation was found between clindamycin use in either the curr

High-pressure liquid chromatographic assay of ceftizoxime with an anion-exchange extraction technique.

BACKGROUND The molecular epidemiology of endemic and outbreak Clostridium difficile strains across time is not well known. METHODS HindIII restriction endonuclease analysis (REA) typing was performed on available clinical C. difficile isolates from 1982 to 1991. RESULTS The annual incidence of C. difficile infection (CDI) ranged from 3.2 to 9.9 cases per 1000 discharges and was significantly higher in 1982, 1983, 1985, and 1991 (high-incidence years) than in other years (mean standard deviation number of cases for the high- vs the low-incidence years, 121.8 +/-20.4 and 70.0 +/-15.0; P =.002). A total of 696 (76.6%) of 908 C. difficile isolates were available for REA typing over the 10-year period. Large clusters (>or=10 CDI cases in consecutive months) were caused by REA types B1 and B2 in 1982 and 1983, F2 and B1 in 1985, and K1 in 1991 (high-incidence years). Small clusters of 4-9 CDI cases in consecutive months were caused by REA types G1 (1984), Y4 and Y6 (1987), Y2 (1988), L1 (1989), Y1 (1990), and K1 (1991). Current epidemic REA group BI (unrelated to type B1) was isolated 6 times, twice in 1984, 1988, and 1990. CONCLUSIONS Years with a high incidence of CDI were associated with large clusters of specific REA types that changed yearly. The molecular epidemiology of CDI in this hospital was characterized by a wide diversity of C. difficile types and an ever-changing dominance of specific C. difficile types over time. The current epidemic BI group was found sporadically on 6 occasions. A changing CDI molecular epidemiology should be expected in the future.

Development of a rapid and efficient restriction endonuclease analysis typing system for Clostridium difficile and correlation with other typing systems.

Summary The fever response of rabbits to group A streptococcal pyrogenic exotoxin (SPE) type C was effectively reduced by pretreatment of the animals with the antipyretics, indomethacin (25 mg/kg), acetylsalicylate (200 mg/kg), and cortisone (5 mg on each of three preceding days and 2 hr before given SPE). Indomethacin and acetylsalicylate also significantly reduced the fever response of rabbits to SPE type C if given near the time of maximum fever response (4 hr after SPE). None of the antipyretic agents protected the rabbits from SPEs capacity to enhance susceptibility to lethal endotoxin shock. These data suggest that SPE fever production required prostaglandin synthesis, probably PGE1 or PGE2, and that the mechanism of fever production by SPE may be different from the mechanism underlying the enhancement of lethal endotoxin shock. Studies are presently being done to elucidate further the mechanisms of fever production and enhancement of lethal endotoxin shock by SPE.

Production of Pyrogenic Exotoxin by Groups of Streptococci: Association with Group A

An anion-exchange extraction method was used in conjunction with high-pressure liquid chromatography for assay of ceftizoxime in 181 serum samples. Comparison of this method with bioassay gave a linear regression line described by Y = 1.11 + 0.98 X, with a correlation coefficient of 0.984. The anion-exchange extraction method is a fast, reliable method of preparing serum samples containing ceftizoxime for assay by liquid chromatography.