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Query: UMLS:C0004610 (bacteremia)
 13,199 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A mouse model of bacteremia was used to compare the efficacies of 1.5- and 3.0-g intravenous doses of ampicillin-sulbactam. Seven strains of Escherichia coli producing various levels of TEM-1 beta-lactamase were used as the challenge isolates. These strains included six clinical isolates (MICs from 2/1 micrograms/ml [with 2 and 1 microgram/ml being the respective concentrations of ampicillin and sulbactam] to 32/16 micrograms/ml) with similar degrees of virulence in mice and a laboratory genetic transformant (E. coli AFE) which hyperproduces TEM-1 (MIC = 128/64 micrograms/ml). Human pharmacokinetics were simulated by injecting mice subcutaneously twice (1 h apart) with ampicillin-sulbactam at concentrations of 40 mg/kg of body weight (1.5 g) and 80 mg/kg (3.0 g). Against two clinical isolates for which ampicillin-sulbactam MICs were < or = 8/4 micrograms/ml, no difference was observed in either the rate or level of killing between the two doses, and both doses were 100% protective against lethal infection. Against the four clinical isolates for which ampicillin-sulbactam MICs were between 16/8 and 32/16 micrograms/ml, a slight delay in killing was noted with three of the strains. This delay was followed by a rapid 2- to 3-log drop in the level of bacteremia, and both doses of ampicillin-sulbactam were 100% protective against lethal septicemia. With strain AFE, no killing was observed with the 40-mg/kg dose compared with a 2-log killing with the 80-mg/kg dose. This difference in killing correlated with a decreased protective efficacy of the 40-mg/kg dose. These data suggest that the 1.5-g preparation of ampicillin-sulbactam is as effective as the 3.0-g dose in the treatment of experimentally induced E. coli bacteremia, as long as ampicillin-sulbactam MICs are 32/16 micrograms/ml or less.
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PMID:Comparison of ampicillin-sulbactam regimens simulating 1.5- and 3.0-gram doses to humans in treatment of Escherichia coli bacteremia in mice. 778 98

A clinical isolate of Pseudomonas aeruginosa resistant to pefloxacin (Pef) but susceptible to ciprofloxacin (Cip) was studied to compare the in vitro and in vivo activities of Pef, ofloxacin (Ofl), and Cip. The time-kill curve method showed no bactericidal activity for Pef and Ofl, but a reduction of 4 log10 CFU/ml was achieved with Cip at 1 h. A model of experimental P. aeruginosa pneumonia was used to evaluate in vivo the relevance of the difference in susceptibility observed in vitro. At 36 h, a 100% cumulative survival rate was observed in Cip-treated rats, which was far higher than the survival rate obtained with Pef (53%) or Ofl (46%) (P < 0.001). At 4 h, no bacteremia was observed in Cip-treated rats, whereas 93% of the Pef-treated rats and 80% of the Ofl-treated rats were bacteremic (P < 0.001). The best pulmonary bacterial clearance was observed with Cip. Interestingly, Pef and Ofl, to which the strain was resistant in vitro, showed a fairly good in vivo activity despite sub-MIC concentrations. Cip was more effective than Pef and Ofl in terms of pulmonary and systemic bactericidal activity and provided the best survival rate in animals. We conclude that differences between the different quinolones in terms of the organism's sensitivity assessed in vitro may be relevant and that it might be useful to reconsider the use of a quinolone to which P. aeruginosa shows resistance if the organism shows sensitivity to no other agent.
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PMID:Should Pseudomonas aeruginosa isolates resistant to one of the fluorinated quinolones be tested for the others? Studies with an experimental model of pneumonia. 779 72

A case of bacteremia caused by a multiresistant strain of Capnocytophaga sputigena in a patient with hematological malignancy is described. The strain presented with a pattern of marked resistance to beta-lactams, with MICs of > 256 mg/liter for ampicillin, ticarcillin, piperacillin, cefazolin, and cefuroxime, 64 mg/liter for cefotaxime, and 32 mg/liter for ceftazidime. In addition, the MIC of ciprofloxacin was 16 mg/liter. Both of these groups of antimicrobial agents are frequently used in the empiric treatment of infections in immunocompromised patients. The appearance of resistant strains suggests the need for antimicrobial susceptibility studies in all patients with severe infections caused by Capnocytophaga spp. or other capnophilic organisms present in the oral microflora of these patients.
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PMID:Bacteremia by multidrug-resistant Capnocytophaga sputigena. 802 14

An outbreak of bacteremia caused by Enterococcus faecium with high-level resistance to vancomycin (MIC of > or = 256 micrograms/ml), ampicillin (MIC of > or = 64 micrograms/ml), and gentamicin or streptomycin (MIC of > or = 2,000 micrograms/ml) occurred in an adult oncology unit from June 1991 to May 1992. Active surveillance for the presence of this organism in stool or perianal cultures was begun in September 1991. Between June 1991 and May 1992, seven patients with bacteremia and 22 noninfected carriers of the organism in stool were identified. The vanA gene, tested for by PCR and gene probe, was present in all isolates evaluated. All bacteremic patients also had resistant E. faecium present in a stool or perianal culture; the stool isolates tested were closely related to the respective blood isolates as determined by pulsed-field gel electrophoresis. Antibiotic regimens using high-dose ampicillin and an aminoglycoside were ineffective with four patients. Five patients (71%) had multiple positive blood cultures; four of these patients died. Following a multiple logistic regression analysis, it was found that bacteremic patients received a significantly greater number of total antibiotic days compared with noninfected stool carriers (P = 0.019). The emergence of E. faecium with high-level resistance to vancomycin, ampicillin, and aminoglycosides underscores the importance of performing susceptibility testing on all clinically significant isolates. In the neutropenic adult oncology patient, bacteremia with this organism is of probable gastrointestinal origin, is often persistent, and is refractory to treatment with ampicillin in combination with an aminoglycoside. Prolonged use of antibiotics may predispose patients with gastrointestinal colonization to develop bacteremia.
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PMID:Outbreak of vancomycin-, ampicillin-, and aminoglycoside-resistant Enterococcus faecium bacteremia in an adult oncology unit. 809 38

Ten neonates with persistent staphylococcal bacteremia (positive blood cultures for > or = 5 days despite appropriate antibiotic therapy) received intravenous (i.v.) rifampin in combination with vancomycin with or without aminoglycoside. Their mean birth weight and length of gestation were 900 g and 27 weeks, respectively. Their ages at the time of infection ranged from 6 to 64 days (mean, 26 days). The staphylococcal isolates were methicillin-resistant Staphylococcus aureus (five isolates), methicillin-susceptible S. aureus (two isolates), and coagulase-negative staphylococci (three isolates). The mean number of bacteremia days prior to administration of i.v. rifampin was 8.3 (range, 5 to 15 days), despite a mean peak vancomycin concentration of 33 micrograms/ml. The dosing of rifampin varied from 2.5 to 10 mg/kg of body weight every 12 h. The mean duration of the rifampin course was 9.7 days (range, 3 to 16 days). Of the 10 neonates, 8 (80%) had sterile blood cultures within 24 h, 1 (10%) had a sterile blood culture within 48 h, and 1 (10%) had a sterile blood culture within 5 days of being placed on i.v. rifampin. No adverse effects were noted in this small group of infants. Seven of the 10 neonates survived; three died from unrelated complications. The MIC ranges of amikacin, vancomycin, and rifampin for the isolates were 2.0 to 16, 0.5 to 2.0, and 0.0013 to 0.04 micrograms/ml, respectively. We also studied eight infants, with a mean age of 23 days, who were receiving i.v. or oral rifampin at a dose of 10 mg/kg/day. For i.v. administration, the peak serum concentration of rifampin (mean +/- standard deviation) was 4.02 +/- 1.22 microgram/ml. The mean trough level at 12 h postifution was 1.11 +/- 0.48 micrograms/ml. For oral administration, the concentrations of rifampin in serum ranged from 0.59 to 2.86 micrograms/ml (mean, 1.86 +/- 0.96 microgram/ml) at 2 h postingestion, increasing to a peak concentration of 2.8 micrograms/ml at 8 h postingestion. The mean 12-h postingestion level was 0.77 +/- 0.03 microgram/ml. From the study of this limited series of neonates, rifampin appears to be a safe and effective addition to therapy when staphylococcal bacteremia is persistent despite vancomycin treatment.
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PMID:Use of intravenous rifampin in neonates with persistent staphylococcal bacteremia. 828 24

Patients with enterococcal bacteremia due to strains with and without high-level gentamicin resistance (HLGR; MIC, > 2,000 mg/L) were compared. Between 1986 and 1991, there were 178 episodes of enterococcal bacteremia: 47 and 131 episodes, respectively, due to enterococcal strains with and without HLGR. Sixty-two, 57, and 59 episodes, respectively, were in patients with transient bacteremia (a single positive blood culture), bacteremia (two or more positive blood cultures), and polymicrobial bacteremia. Nosocomial bacteremia accounted for 61.7% and 51.1% of episodes due to strains with and without HLGR, respectively. All isolates were strains of Enterococcus faecalis except for 13 strains of Enterococcus faecium, 4 of Enterococcus avium, and 3 of Enterococcus durans. Although the mortality was slightly higher among patients infected with strains with HLGR than among those infected with strains without HLGR (38.3% vs. 30.5%, respectively), there was no statistical difference. The mortality rate was adversely affected by old age (P < .01) and rapidly and ultimately fatal underlying conditions (P < .001). The addition of gentamicin to the treatment regimens had no effect on mortality.
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PMID:Comparison of patients with enterococcal bacteremia due to strains with and without high-level resistance to gentamicin. 835 50

The role of aminoglycosides in the treatment of infective endocarditis is well established. The combination of a beta-lactam with an aminoglycoside shortens the treatment of endocarditis due to penicillin-sensitive streptococci (MIC < or = 0.1 micrograms/mL) when compared to beta-lactams alone. Patients at higher risk (e.g. with prosthetic valves, clinical duration of symptoms > 3 months) should be treated with penicillin for 4 weeks in combination with an aminoglycoside for 2 weeks. Once-daily dosing (ODD) of aminoglycosides can be recommended in penicillin-sensitive streptococcal endocarditis. The treatment of endocarditis due to streptococci relatively and/or highly resistant to penicillin requires combined treatment with penicillin plus an aminoglycoside for a longer duration. At present ODD of aminoglycosides cannot be recommended. Enterococcal endocarditis requires combined treatment for 4 to 6 weeks. Based upon experimental data, ODD of aminoglycosides appears to be markedly inferior to q 8 h dosing. Enterococcal isolates should be screened for high-level resistance to streptomycin and gentamicin. Gentamicin is the preferred agent if susceptibility testing is not performed. Aminoglycosides are administered during the initial 3 to 5 days of treatment for staphylococcal endocarditis on native valves in order to shorten the duration of bacteremia. For staphylococcal prosthetic valve endocarditis, aminoglycosides are administered for the initial 2 weeks of treatment. However, there are no reliable clinical data for methicillin-susceptible isolates to support this recommendation. In prosthetic valve endocarditis due to coagulase-negative staphylococci combination with an aminoglycoside appears to suppress the emergence of rifampin-resistant variants during treatment. There are no data on ODD of aminoglycosides in staphylococcal endocarditis. Right-sided staphylococcal endocarditis due to methicillin-susceptible staphylococci is adequately treated with a two-week course of a beta-lactam plus an aminoglycoside. This short regimen can be recommended for low risk patients, e.g. those without significant heart failure and vegetations < 2 cm3 and with an aminoglycoside-susceptible isolate.
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PMID:[Aminoglycosides in the treatment of infectious endocarditis]. 867 14

In 1875, 7 years prior to the description of the Koch bacillus, Klebs visualized the first Streptococcus pneumoniae in pleural fluid. Since then, this organism has played a decisive role in biomedical science. From a biological point of view, it was extensively involved in the development of passive and active immunization by serotherapy and vaccination respectively. Genetic transformation was also first observed in S. pneumoniae, leading to the discovery of DNA. From a clinical point of view, S. pneumoniae is today still a prime cause of otitis media in children and of pneumonia in all age groups, as well as a predominant cause of meningitis and bacteremia. In adults, bacteremia still has a mortality of over 25%. Although S. pneumoniae remained very sensitive to penicillin for many years, penicillin-resistant strains have emerged and increased dramatically over the last 15 years. During this period the frequency of penicillin-resistant isolates has increased from < or = 1% to frequencies varying from 20 to 60% in geographic areas as diverse as South Africa, Spain, France, Hungary, Iceland, Alaska, and numerous regions of the United States and South America. In Switzerland, the current frequency of penicillin-resistant pneumococci ranges between 5 and > or = 10%. The increase in penicillin-resistant pneumococci correlates with the intensive use of beta-lactam antibiotics. The mechanism of resistance is not due to bacterial production of penicillinase but to an alteration of the bacterial target of penicillin, the so-called penicillin-binding proteins. Resistance is subdivided into (1) intermediate level resistance (minimal inhibitory concentration [MIC] of penicillin of 0.1-1 mg/l) and (2) high level resistance (MCI > or = 2 mg/l). The clinical significance of intermediate resistance remains poorly defined. On the other hand, highly resistant strains have been responsible for numerous therapeutic failures, especially in cases of meningitis. Antibiotics recommended against penicillin-resistant pneumococci include cefotaxime, ceftriaxone, imipenem and in some instances vancomycin. However, penicillin-resistant pneumococci tend to present cross-resistances to all the antibiotics of the beta-lactam family and could even become resistant to the last resort drugs mentioned above. Thus, the explosion of resistance to penicillin in pneumococci is a ubiquitous phenomenon which must be fought against by (1) avoiding excessive use of antibiotics, (2) the practice of microbiological sampling of infected foci before treatment, (3) the systematic surveillance of resistance profiles of pneumococci against antibiotics and (4) adequate vaccination of populations at risk.
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PMID:[Antibiotic resistance in pneumococci]. 872 Mar 23

A 39-year-old male with acute myelogenous leukemia and concomitant porphyria cutanea tarda was admitted to the hospital for consolidation chemotherapy of his leukemia. During his hospitalization, he developed cellulitis of the left hand and persistent bacteremia with a yellow-pigmented, nonfermenting coryneform bacterium that was identified as Aureobacterium sp. The portal of entry for the Aureobacterium infection was probably through the skin lesions due to porphyria cutanea tarda. The infection developed while the patient was receiving vancomycin prophylaxis, and the vancomycin MIC for the isolate was 32 micrograms/ml.
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PMID:Vancomycin-resistant Aureobacterium species cellulitis and bacteremia in a patient with acute myelogenous leukemia. 881 96

In June 1993, the National Committee for Clinical Laboratory Standards (NCCLS) recommended stringent new interpretive guidelines for antibiotics indicated for Streptococcus pneumoniae meningitis. To assess the predictive values of the recommended breakpoints, retrospective data were collected from patients who had S. pneumoniae infections and were treated with cefotaxime monotherapy. Susceptibilities based on the NCCLS interpretative categories were compared with clinical and bacteriologic outcomes. In 76 evaluable patients, the most common infections were bacteremia-septicemia (n = 49), meningitis (n = 37), and lower respiratory tract infection (n = 14). Under the NCCLS breakpoints proposed in 1993, 55 isolates would have been classed as susceptible to cefotaxime (MIC, < or = 0.25 microgram/ml), 18 would have been classed as intermediate (MIC, 0.5 to 1.0 microgram/ml), and 2 would have been classed as resistant (MIC, > or = 2 micrograms/ml). Of 75 cefotaxime-treated patients for whom cefotaxime MICs were recorded, 73 were clinically cured or improved (37 of 37 with meningitis and 36 of 38 with other infections). One case of bacteremia and one case of bone-and-joint infection were scored as therapeutic failures because initial monotherapy had to be modified because of an adverse drug reaction. Excluding these patients, there were 18 patients infected with S. pneumoniae that would have been classed as not fully susceptible (i.e., MICs > or = 0.5 microgram/ml); all of these patients were cured or improved. The results of this analysis demonstrate that successful treatment with cefotaxime did not correlate well with the guidelines for the susceptibility of pneumococcal isolates to either penicillin or cefotaxime established by the 1993 NCCLS breakpoint recommendations. Because of this study and other similar findings, the NCCLS adopted more clinically relevant guidelines in 1994.
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PMID:Relationship of MICs to efficacy of cefotaxime in treatment of Streptococcus pneumoniae infections. 884 47


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