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PubMed1995

Enterococcus faecium and Enterococcus faecalis bacteremia: acquisition and outcome.

The incidence of enterococcal bacteremia due to Enterococcus faecium is increasing. To understand the clinical significance of E. faecium bacteremia, we compared 16 patients who were bacteremic due to E. faecium to 56 patients who were bacteremic due to Enterococcus faecalis. E. faecium bacteremia developed most frequently in severely ill patients with fever or hypothermia accompanied by CNS, cardiovascular, and/or pulmonary dysfunction, while E. faecalis bacteremia occurred most often in less seriously ill patients. Nosocomial acquisition, cancer, neutropenia, renal insufficiency, current corticosteroid therapy, and previous treatment with broad-spectrum antibiotics were significantly more frequently associated with E. faecium bacteremia. Mortality was significantly higher among patients infected with E. faecium than among those infected with E. faecalis (50% vs. 11%; P = .001); this was true particularly among patients with monomicrobial or nosocomial bacteremia, those who had previously received antibiotic treatment, and those with cancer. Death due to enterococcal bacteremia was observed only among severely ill patients. These findings suggest that E. faecium often infects debilitated patients and that such infection appears to be a significant factor contributing to mortality.

Bacteremia↗
PubMed1996

Lactobacillus bacteremia: description of the clinical course in adult patients without endocarditis.

Lactobacillus bacteremia in the absence of endocarditis is a rare entity, and the clinical relevance of such bacteremia remains unclear. The clinical courses of lactobacillus bacteremia without endocarditis in 43 previously described patients and 12 new patients were reviewed. Bacteremia with Lactobacillus alone occurred in 34 (62%) of the patients, and 12 (22%) of the patients had bacteremia with other organisms, including Lactobacillus. Lactobacillus was isolated from another site in 18 (33%) of these patients. Intravenous catheter infections were not noted in these patients. Underlying conditions included cancer (6 patients), organ transplantation (9), diabetes mellitus (4), and recent surgery (12). Fever occurred in all patients, and eight (15%) of the patients experienced a sepsis syndrome. The mortality rate was 14%; however, only three deaths were attributed soley to lactobacillus sepsis. Lactobacillus bacteremia is an uncommon condition that usually occurs in patients with severe underlying illnesses and is frequently seen as a part of a polymicrobial infection. Blood cultures positive for Lactobacillus represent true infection and not contamination. Although resistance to commonly used antibiotics is common, the mortality rate associated with this bacteremia appears to be low.

Adult↗
PubMed1996

Anaerobic bacteremia.

The results of early studies showed that anaerobes account for 20% of all bacteremias; more-recent data suggest that these organisms account for approximately 4% (0.5%-9%) of bacteremias ( or approximately one case per 1,000 admissions), with variation by geographic location, hospital patient demographics, and especially, patient age. Elderly persons seem to be at increased risk for developing anaerobic bacteremia while young children (2-5 years of age) are at the least risk. Bacteroides fragilis is the most common blood isolate recovered from patients with anaerobic bacteremia; this organism and species of the B. fragilis group account for approximately 55% of anaerobic bacteremias. B. fragilis bacteremia is associated with a mortality of 19%, with a mortality risk of 3.2; a 16-day increase in hospital stay; and often, intra-abdominal disease. Associated risks for mortality include chronic liver disease and congestive heart failure. There is value in performing separate anaerobic blood cultures; clinicians at each institution should determine the prevalence of anaerobic bacteremia and use this information to guide blood-culture practices.

Age Distribution↗
PubMed1991

High-level gentamicin resistance in Enterococcus faecalis bacteremia.

In a retrospective analysis, patients with bacteremia due to Enterococcus faecalis with and without high-level gentamicin resistance (GRE; MIC greater than 2000 micrograms/ml) were compared. Bacteremic patients with GRE (n = 32) had significantly higher rates of nosocomial acquisition and bladder catheterization, longer hospitalizations, and more frequent prior treatment with cephalosporins than did bacteremic patients without high-level resistance (n = 19). Overall mortality was significantly associated with septic shock, high-risk source (intraabdominal, wound, respiratory tract, multiple, unknown), and polymicrobial bacteremia. Higher mortality was observed in GRE bacteremia (47%) than in bacteremia without high-level resistance (37%), but this difference was not statistically significant. For patients with monomicrobial bacteremia, low-risk source (genitourinary tract, intravascular), or treatment with antibiotics appropriate for the enterococcus, higher mortality with GRE bacteremia approached statistical significance. These results suggest that high-level resistance adversely affects survival with a pure E. faecalis bacteremia or low-risk bacteremic source. Also, response to antibiotic therapy may be diminished by high-level resistance.

Adult↗
PubMed1994

Transient bacteremia due to Mycobacterium avium complex in patients with AIDS.

It is generally assumed that Mycobacterium avium complex (MAC) bacteremia, once it develops, is unremitting. On the basis of this presumption, changes in the level of mycobacteremia are used to gauge therapeutic response. In 7 (12%) of 60 patients enrolled in a prospective trial of MAC bacteremia and AIDS, bacteremia became undetectable before the initiation of antimycobacterial therapy. Patients with transient bacteremia reported fewer and shorter symptoms and survived longer than those with sustained bacteremia (59 vs. 31 weeks; P = .022). There was no difference in the duration of AIDS, CD4+ cell count, hematocrit, or body weight between groups. Two additional patients with transient bacteremia were identified outside this study setting. Despite disappearance of detectable mycobacteremia and subsequent administration of antimycobacterial agent(s), bacteremia once again became detectable in 6 patients 4-45 weeks after their negative pretreatment cultures. Patients with disseminated MAC may have fluctuating levels of mycobacteremia that become undetectable in the absence of antimycobacterial therapy.

AIDS-Related Opportunistic Infections↗
PubMed1997

Prior antimicrobials and staphylococcal bacteremia in HIV-infected patients.

OBJECTIVE: Many drugs used for prophylaxis against opportunistic infections in AIDS also have activity against common bacteria. This study was performed to delineate relationships between prior use of antimicrobials and Staphylococcus aureus bacteremia. DESIGN: To compare prior exposure to selected antimicrobial drugs in patients who had S. aureus bacteremia and in controls who did not, a nested case-control study was conducted within a cohort of HIV-infected persons followed in an outpatient clinic. METHODS: Using a computerized database based on HIV clinic records, 48 cases with S. aureus bacteremia were compared against 188 controls selected from patients with CD4 cell counts < 200 x 10(6)/l. Information on demographic risk factors and antimicrobial drug use was analysed using conditional logistic regression. RESULTS: Injecting drug use was strongly associated with S. aureus bacteremia. Rifabutin use was associated with decreased risk of S. aureus bacteremia [conditional relative risk (RR) 0.308, 95% confidence interval (CI) 0.096-0.991] in univariate analysis, near statistical significance in multivariate analysis (RR 0.314, 95% CI 0.096-1.023). The bacteremias were not significantly associated with use of trimethoprim-sulfamethoxazole, quinolones, newer macrolides (azithromycin and clarithromycin), clindamycin or dapsone. CONCLUSIONS: Rifabutin may be associated with diminished risk of S. aureus bacteremia incidental to use for other purposes in HIV infection. Further study is needed to assess effects on microbial resistance.

AIDS-Related Opportunistic Infections↗
PubMed1993

The frequency of bacteremia and fungemia following wound cleaning and excision in patients with large burns.

Twenty-eight patients with large burn injuries (mean total body surface area burned, 47.1%) who underwent 112 wound cleaning and staged early excision procedures were studied prospectively for bacteremia and fungemia induced by wound manipulation. The patients were given an aminoglycoside preoperatively, perioperatively, and postoperatively. Blood samples were obtained immediately before removal of dressings, after wound cleaning, after 30 minutes of surgery, at the end of each procedure, and 1 hour after surgery was completed. In a group of control patients blood samples were obtained immediately before the dressings were removed, after wound cleaning was completed, and 1 hour afterward. In a second group of control patients blood samples were obtained serially while the burn wounds remained undisturbed. None of the control patients received prophylactic aminoglycosides. Induced bacteremia or fungemia was documented in 50 instances of burn wound cleaning and excision; 31 cases of bacteremia or fungemia occurred after wound cleaning alone. Spontaneous bacteremia, i.e., that occurring in the absence of burn wound manipulation, was demonstrated in 3 of 18 blood culture series, whereas induced bacteremia was observed after 11 of the 17 burn wound cleaning procedures alone. The frequency of bacteremia tended to be higher for patients with inhalation injury than for those with no lung involvement. However, lung infection did not seem to account for many of the positive results of blood culture in this study. In contrast, burn wound infection contributed significantly to both spontaneous and induced bacteremia or fungemia. The micro-organisms most frequently isolated were staphylococci (50%) and enterococci (15.1%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1997

Incidence of bacteremia after burn wound manipulation in the early postburn period.

BACKGROUND: Transient bacteremia associated with burn wound manipulation is considered a frequent occurrence and is commonly cited as an indication for perioperative antibiotic prophylaxis in burn patients. METHODS: In a prospective clinical setting, blood cultures (BC) were obtained from 19 burn patients at the following intervals: 30 minutes before wound cleansing (WC) or wound excision (WE), 30 minutes after the start of WC or WE, hourly until procedure completion, and 1 hour after completion. Burn wound biopsy for histologic grading and microbial culture was performed after the first BC. RESULTS: Twenty-two WC and 20 WE episodes were evaluated by 67 and 76 BC sets, respectively. Patients had a mean age of 42.8 years and mean burn size of 50% of the body surface area. Three WC episodes (13.6%) and four WE procedures (20.0%) were associated with postprocedure bacteremia. Two patients had both preprocedure and postprocedure bacteremia later attributed to nonburn wound infections. Excluding these cases, the bacteremia rate was 12.5% (9.5% from WC and 15% from WE). Wound biopsy culture and histologic analysis did not predict the occurrence of bacteremia. CONCLUSION: Current therapy is associated with a lesser incidence of burn wound manipulation-induced bacteremia than reported in prior series. The discordance between wound biopsy and BC results, the absence of positive histology, and the similarity of bacteremia occurrence rates with WC and WE confirm the effectiveness of current techniques of microbial control in burn wounds and question the need for perioperative antibiotic therapy in patients with burns involving less than 40% of the total body surface during the first 10 postburn days.

Adult↗
PubMed1999

Bacteremia-associated pneumococcal pneumonia and the benefit of initial parenteral antimicrobial therapy.

OBJECTIVES: To describe clinical characteristics of patients with bacteremia-associated pneumococcal pneumonia (BAPP) and evaluate features that may distinguish these patients from those with uncomplicated pneumococcal bacteremia. To determine the impact of the route of initial antibiotic therapy on the clinical course of patients with BAPP. DESIGN/METHODS: Retrospective review of children with pneumococcal bacteremia comparing those with pneumonia to those without focal infections. RESULTS: We identified 110 patients with BAPP and 112 patients with pneumococcal bacteremia alone. Patients with pneumonia were significantly older (mean age, 34 vs. 19 months; P = 0.002) and more likely to present with cough/congestion (28% vs. 14%; P = 0.01) or difficulty breathing (12% vs. 4%; P = 0.047). There was no difference in mean temperature (39.5 vs. 39.7 degrees C; P = 0.3), mean white blood cell count WBC (21.9 vs. 22.6 x 1000/mm,3 P = 0.5) or presence of tachypnea (23% vs. 22%, P = 0.8). Sixty-one patients (55%) with pneumonia were discharged home from the initial visit in the emergency department. Those who received a parenteral antibiotic before discharge, when compared with the group who received an oral antibiotic alone, were more likely to have an improved condition (95% vs. 67%, P = 0.03) and were less likely to be admitted to the hospital (0% vs. 24%; P = 0.007) at follow-up. CONCLUSIONS: Children with bacteremia-associated pneumococcal pneumonia are older and more likely to complain of cough/congestion or difficulty breathing than those with uncomplicated pneumococcal bacteremia. The use of a parenteral antibiotic at the initial visit for children with bacteremia-associated pneumococcal pneumonia resulted in a lower admission rate and more likely parental report of improved condition at follow-up than those for children treated only with an oral antibiotic.

Anti-Bacterial Agents↗
PubMed1996

Relevance and risk factors of enterococcal bacteremia following liver transplantation.

To analyze the clinical characteristics of and identify specific risk factors for enterococcal bacteremia following liver transplantation, we performed a study in 405 consecutive liver transplantation recipients prophylaxed with a selective bowel decontamination regimen. Seventy enterococcal bacteremias in 52 patients were identified. Enterococcus faecalis (50) outnumbered Enterococcus faecium isolates (18), and 49% of enterococcal bacteremias were polymicrobial. Biliary tree complications were present in 34% of enterococcal bacteremias. Of the 15 deaths (29%) among the patients with enterococcal bacteremia, 4 were directly associated with enterococcal bacteremia. In a multivariate analysis, Roux-en-Y choledochojejunostomy (P=0.005), a cytomegalovirus-seropositive donor (P=0.013), prolonged transplantation time (P=0.02), and biliary stricturing (P=0.016) were identified as significant risk factors. Other risk factors identified in a univariate analysis included primary sclerosing cholangitis (P=0.009) and symptomatic cytomegalovirus infection (P=0.008). Enterococcal bacteremia is a frequent infectious complication in liver transplantation recipients receiving selective bowel decontamination. Its association with cytomegalovirus and biliary tree abnormalities suggest specific areas for prophylactic intervention.

Anastomosis, Roux-en-Y↗
PubMed2003

Linezolid for the treatment of children with bacteremia or nosocomial pneumonia caused by resistant gram-positive bacterial pathogens.

BACKGROUND: Nosocomial infections, particularly hospital-acquired pneumonia (HAP) and bacteremia, are an increasing concern in pediatric hospitals and pediatric intensive care units. Gram-positive pathogens are a leading cause of these infections in children. Linezolid is well-tolerated and as effective as vancomycin in the treatment of these infections in adults. OBJECTIVE: To evaluate the clinical effectiveness and safety of iv/oral linezolid and iv vancomycin in children with resistant Gram-positive HAP or bacteremia. METHODS: Hospitalized children <12 years of age were randomized 2:1 to linezolid or vancomycin. Patients received linezolid 10 mg/kg iv every 8 h with the option to change treatment to oral linezolid suspension 10 mg/kg every 8 h or iv vancomycin 10 to 15 mg/kg every 6 to 24 h. Clinical response was evaluated at follow-up. Results from an analysis of patients with HAP or bacteremia are presented. RESULTS: Thirty-nine patients (linezolid, 23; vancomycin, 16) with HAP and 113 patients with bacteremia (linezolid, 81; vancomycin, 32) were included in the intent-to-treat group. Clinical cure rates for clinically evaluable patients with HAP did not differ between treatment groups (linezolid, 90.0% and vancomycin, 100%; P = 0.305). No significant difference was seen in clinical cure rates in the clinically evaluable population between the linezolid and vancomycin groups for patients with catheter-related bacteremia (84.8 and 80.0%, respectively; P = 0.716) or patients with bacteremia of unknown source (79.2 and 69.2%, respectively; P = 0.501). In this subset fewer linezolid-treated patients had drug-related adverse events than did vancomycin-treated patients (19.4% vs. 28.3%; P = 0.230). Similar percentages of patients with laboratory abnormalities, including selected hematologic parameters, were seen in both treatment groups. CONCLUSIONS: Intravenous/oral linezolid was well-tolerated and as effective as vancomycin in treating children with resistant Gram-positive HAP or bacteremia.

Acetamides↗
PubMed2006

Changing epidemiology of outpatient bacteremia in 3- to 36-month-old children after the introduction of the heptavalent-conjugated pneumococcal vaccine.

BACKGROUND: The introduction of routine vaccination with heptavalent conjugated pneumococcal vaccine has changed the overall incidence of bacteremia in children 3 months-3 years old. OBJECTIVE: To describe the changing incidence and etiology of bacteremia in previously healthy toddlers presenting to outpatient clinical settings. METHODS: Retrospective case series of all blood cultures obtained between September 1998 and August 2003 in Kaiser Permanente Northern California outpatient clinics and emergency departments from previously healthy children 3 months-3 years old. RESULTS: Implementation of routine vaccination with the conjugated pneumococcal vaccine resulted in an 84% reduction of Streptococcus pneumoniae bacteremia (1.3-0.2%) and a 67% reduction in overall bacteremia (1.6-0.7%) in the study population. The rate of blood culture isolation of contaminating organisms remained unchanged at 1.8%; therefore, by the end of the study, >70% of organisms identified in blood cultures were contaminants. During the 5 study years, total blood cultures drawn decreased by 35% in outpatient pediatric clinics but remained unchanged in emergency departments. By 2003, one-third of all pathogenic organisms isolated from blood cultures were Escherichia coli, one-third were non-vaccine serotype S. pneumoniae, the majority of the remaining one-third were Staphylococcus aureus, Salmonella spp., Neisseria meningitidis and Streptococcus pyogenes. In our population of children routinely immunized with the conjugated pneumococcal vaccine, a white blood cell count >15,000 by itself is a poor predictor of bacteremia in the febrile toddler (sensitivity, 74.0%; specificity, 54.5%; positive predictive value, 1.5%; negative predictive value, 99.5%). CONCLUSION: In the United States, routine vaccinations with Haemophilus influenzae type b and S. pneumoniae vaccines have made bacteremia in the previously healthy toddler a rare event. As the incidence of pneumococcal bacteremia has decreased, E. coli, Salmonella spp. and Staphylococcus aureus have increased in relative importance. The use of the white blood cell count alone to guide the empiric use of antibiotics is not indicated. New guidelines are needed to approach the previously healthy febrile toddler in the outpatient setting.

Bacteremia↗
PubMed1999

Prevalence of the virulence plasmids of nontyphoid Salmonella in the serovars isolated from humans and their association with bacteremia.

To determine if the virulence plasmid is one of the elements contributing to Salmonella bacteremia in humans, 436 clinical Salmonella isolates of different serovars were examined by a specific multiplex polymerase chain reaction assay for the presence of a virulence plasmid. These serovars showed differences in their ability to produce particular disease syndrome in humans. In the serovars usually causing bacteremia without concomitant gastroenteritis (primary bacteremia), i.e., S. choleraesuis, S. dublin, and S. enteritidis in this study, the rate of virulence plasmid carriage was 100%, while among those occasionally generating bacteremia following an episode of gastroenteritis (secondary bacteremia), the majority were plasmidless. Only a portion of S. typhimurium strains harbored a virulence plasmid; however, the rates of virulence plasmid carriage in S. typhimurium were not statistically different between non-fecal and fecal isolates (90% vs. 85%, 0.1 < P < 0.9). These results indicate that the virulence plasmids may be important for primary bacteremia, but not secondary bacteremia, to occur.

Bacteremia↗
PubMed1992

Staphylococcus aureus bacteremia in patients with hematologic disorders.

During the 20-year period, 1972-1991, 27 episodes of Staphylococcus aureus bacteremia, including 10 with methicillin-resistant strains (MRSA), were documented in 26 patients with hematologic disorders, mainly acute leukemia and malignant lymphoma, representing 6% of all 433 episodes of bacteremia in a hematology unit. MRSA replaced methicillin-sensitive strains (MSSA) in the last four years. The skin and upper respiratory tract were the two most common primary foci. Most episodes occurred during neutropenia. Pharyngeal colonization often preceded the development of bacteremia. Antibiotic therapy predisposed to MRSA acquisition during hospitalization, whereas MSSA was mostly detected in admission cultures. Among 22 patients with monomicrobial bacteremia, 19 (86%) survived longer than one week, including all four with MRSA bacteremia who received vancomycin. The survival rate did not differ materially between MRSA and MSSA bacteremias. Secondary foci, chiefly located in the lung, were found in 30% of all patients with S. aureus bacteremia. Prolonged antibiotic therapy, therefore, seems warranted in patients with evident metastatic lesions, although abbreviated therapy is proposed in neutropenic cancer patients.

Adolescent↗
PubMed1996

[Clinical study on bacteremia in patients with liver cirrhosis].

Infections and fever are frequent in patients with liver cirrhosis. Study on bacteremia in cirrhotic patients has not been reported in Japan. In a 16 year period from 1979 to 1994, we collected 39 cases with 40 episodes and 44 microorganisms of bacteremia for this study. The incidence of bacteremia in cirrhotic hospital admissions was 4.8% (39/808). Gram negative bacteria were the predominant microorganisms of bacteremia (66%, 29/44). Among them, Escherichia coli, Klebsiella pneumoniae, Vibrio sp. were the three most commonly detected microorganisms. Pseudomonas aeruginosa bacteremia has not been detected. Laboratory data of cirrhotic patients showed that positive blood culture patients had significantly lower serum albumin, prothrombin time and hepaplastin test than negative patients. Focal infection could be diagnosed in only 45% (20/44). The mortality rate was 28% (11/39), but the bacteremia related death (by septic shock) were only 2 cases. The other causes of death were hepatic failure in 9 cases. In conclusion, bacteremia is a important complication of liver cirrhosis. Blood culture is necessary in cirrhotic patients with fever.

Adult↗
PubMed1992

Clinical significance of Staphylococcus warneri bacteremia.

Twenty-seven episodes of bacteremia caused by Staphylococcus warneri were identified at Long Island Jewish Medical Center in New York between 1984 and 1989. Fourteen of these were thought to represent true bacteremias and 13 to represent contaminants. Of the 14 true bacteremias, 5 were in pediatric and 9 were in adult patients. Eight of 14 patients (57%) had catheter-related bacteremia and 5 of 14 had bacteremia of unknown source. There was one case of fulminant native valve S. warneri endocarditis. All cases of catheter-related bacteremia, except one, were nosocomially acquired, and 75% of these patients had an underlying immunosuppressive condition. Only 40% of patients with bacteremias of unknown source were immunocompromised, and S. warneri appeared to be noninvasive in this group. Interestingly, all five of the pediatric isolates were oxacillin susceptible, although four of five were resistant to penicillin, despite the fact these patients were hospitalized an average of 29 days. In contrast, seven of nine adult isolates were resistant to both oxacillin and penicillin. The only case of native valve S. warneri endocarditis occurred in a patient who had no known underlying valvular heart disease, but had an underlying immunosuppressive condition. Identification to species level of coagulase-negative staphylococci may lead to appreciation of the importance of bacteria such as S. warneri as human pathogens.

Adolescent↗
PubMed1995

Reappraisal with meta-analysis of bacteremia, endotoxemia, and mortality in gram-negative sepsis.

Among patients with suspected sepsis, endotoxemia is variably present in association with gram-negative bacteremia. A total of 738 patients with suspected sepsis from 11 studies could be classified into four groups: 131 (18%) patients had both endotoxemia and gram-negative bacteremia (group 1), 87 (12%) had only gram-negative bacteremia (group 2), and 143 (19%) had only endotoxemia (group 3); in 377 (51%) patients neither could be detected (group 4). By the statistical techniques of meta-analysis, the fatality risk for patients with either endotoxemia or gram-negative bacteremia or both was estimated with group-specific case fatality rates from these studies and expressed as an odds ratio (OR; 95% confidence interval [95% CI]) versus patients with these factors absent. This risk was increased marginally when endotoxemia was detected without gram-negative bacteremia (OR, 2.3; 95% CI, 1.3 to 4.0) or the converse (OR, 2.0; 95% CI, 1.0 to 3.8), in contrast to the striking increase when both endotoxemia and gram-negative bacteremia were detected (OR, 6.3; 95% CI, 4.0 to 10.0). Alone, neither endotoxemia nor gram-negative bacteremia is a strong predictor of outcome in patients with suspected sepsis. However, in combination, the two identify a subpopulation with a substantially increased risk of mortality.

Adolescent↗
PubMed2004

Relationship of MIC and bactericidal activity to efficacy of vancomycin for treatment of methicillin-resistant Staphylococcus aureus bacteremia.

We attempted to find a relationship between the microbiological properties of bloodstream isolates of methicillin-resistant Staphylococcus aureus (MRSA) and the efficacy of vancomycin in the treatment of bacteremia. Vancomycin susceptibility testing was performed, and bactericidal activity was determined for 30 isolates from 30 different patients with MRSA bacteremia for whom clinical and microbiological outcome data were available. The majority of these patients had been previously enrolled in multicenter prospective studies of MRSA bacteremia refractory to conventional vancomycin therapy. Logistic regression found a statistically significant relationship between treatment success with vancomycin and decreases in both vancomycin MICs (< or =0.5 microg/ml versus 1.0 to 2.0 microg/ml; P = 0.02) and degree of killing (reduction in log(10) CFU/milliliter) by vancomycin over 72 h of incubation in vitro (P = 0.03). For MRSA isolates with vancomycin MICs < or = 0.5 microg/ml, vancomycin was 55.6% successful in the treatment of bacteremia whereas vancomycin was only 9.5% effective in cases in which vancomycin MICs for MRSA were 1 to 2 microg/ml. Patients with MRSA that was more effectively killed at 72 h by vancomycin in vitro had a higher clinical success rate with vancomycin therapy in the treatment of bacteremia (log(10) < 4.71 [n = 9], 0%; log(10) 4.71 to 6.26 [n = 13], 23.1%; log(10) > 6.27 [n = 8], 50%). We conclude that a significant risk for vancomycin treatment failure in MRSA bacteremia begins to emerge with increasing vancomycin MICs well within the susceptible range. Elucidating the mechanisms involved in intermediate-level glycopeptide resistance in S. aureus should begin by examining bacteria that begin to show changes in vancomycin susceptibility before the development of obvious resistance. Prognostic information for vancomycin treatment outcome in MRSA bacteremia may also be obtained by testing the in vitro bactericidal potency of vancomycin.

Adult↗