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At least 19 recordsLinked to original sources

PubMed1976

False-positive blood cultures. Association with nonsterile blood collection tubes.

A substantial increase in blood cultures positive for a Serratia marcescens strain unusually sensitive to antibiotics was noted in two large hospitals within six months. Because the patients' illnesses seemed incompatible with Serratia bacteremia, contamination of blood cultures was suspected. Investigation suggested that pediatric-sized vacuum tubes containing ethylenediamine tetraacetic acid (EDTA) were the source of the organisms, and the epidemic strain of Serratia was recovered from 41 (35%) of the 116 tubes cultured. Mock trials showed that reflux from tube to syringe can occur while vacuum tubes are being filled. Because contaminated EDTA tubes were sometimes inoculated before blood culture bottles in these hospitals, cross-contamination occurred. Most evacuated specimen tubes are not guaranteed sterile by the manufacturer. False-positive blood cultures stemming from the use of nonsterile tubes can be eliminated by inoculating blood culture bottles before other specimen tubes. Because false-positive blood cultures may lead to unnecessary antibiotic therapy, health-care workers should guard against the potential hazard associated with use of these tubes.

Blood↗

PubMedDate not supplied

[Blood culture results from 1967 to 1975 and drug sensitivity of bacteria isolated by blood culture in the last three years (1974-1976) (author's transl)].

The blood culture results of patients of S. M. Nuova Hospital of Florence (Italy) have been examined in a period of nine years (1967-1976). We can attest from this results that in the last years of this period we have had an increase of the number of Enterobacteriaceae from blood culture. In the meanwhile we have had a decrease of positive results that is not due to an increase of the number of blood culture; in fact it has been doubled, but this decrease is mostly due to a larger number of examinated patients that to an increase of blood culture for each patient. Introduction in the routine of a diphasic culture system (Castañeda) commercially available has allowed contaminants' decrease. Antibiotic resistance of most important bacteria isolated in the last three years (1974-1976) were carry out.

Anti-Bacterial Agents↗

PubMed1979

Evaluation of ten anaerobic blood culture media.

Selection of an anaerobic blood culture based upon clinical findings that have compared the isolation rates of bacteremic agents from different blood culture media. No agreement has been reached as to which of the commercially available blood culture media is optimal for detection of bacteremia. The purpose of this study was to determine the rates of recovery of anaerobic microorganisms from various anaerobic blood culture media. The blood culture media were inoculated with a small inoculum of microorganisms in the presence or absence of an erythrocyte-serum mixture. The results demonstrated that the type of medium and the erythrocyte-serum mixture influenced the ability of blood culture media to support the growth of microorganisms. The majority of the media failed to support the growth of 87% or more of the microorganisms within four days after inoculation. Pre-reduced brain-heart infusion broth supported the growth of a larger proportion of microorganisms than the other types of blood culture media.

Anaerobiosis↗

PubMed1977

Pseudobacteremia: false-positive blood cultures from mist tent contamination.

In the seven-month period from July 1975 through January 1976, 11 pediatric patients had Acinetobacter calcoaceticus var. anitratus cultured from blood; this organism had not been isolated from pediatric patients in the previous six months. In 10 of 11 patients, only the first of two cultures was positive. All patients recovered uneventfully, although only two were treated with appropriate antibiotics. Nine of 11 had been in mist tents at the time of the culture. Mist cultured from one tent contained the same organism found in the patient's blood culture. Eight of 10 patients, however, had blood for culture drawn from the same needle as samples for other blood work, compared with only three of 13 controls (p = .013); this represented a deviation from proper blood culture technique, and a mock trial confirmed contamination of blood cultures when technique was broken. Contamination by this organism occurred in the tent water reservoir and mist, and the nose and skin of the children were colonized. The hands of respiratory therapy technicians and blood-drawing personnel became contaminated while handling the mist tents. Thorough attention to hand-washing, tent sterilization, and technique in drawing blood cultures stopped the pseudo-epidemic.

Acinetobacter↗

PubMed1978

[Further study of the L forms of Streptococci in blood cultures from the patients with rheumatic fever depending on the course of the disease and the methods of cultivation].

Cultures of blood from patients with rheumatism during the active and inactive phases of the disease, treated and untreated with antibiotics were studied. The following results were obtained in blood cultures (on Klodnisky's medium with a 0.01% cystine) of 105 patients with rheumatism: L-forms of streptococcus were isolated in the 88 cases, irrespective of the severity of the disease or the treatment, streptococcus--in 8, and the result proved to be negative in 9 cases. Hemoculture on broth with a 1% glucose solution proved to be positive (streptococcus) in one patient only. The constancy with which the L-forms of streptococcus were isolated in hemocultures from the patients with rheumatism and also the peculiarity of their pathogenic properties modelling the rheumatism under experimental conditions pointed to their role in the pathogenesis of rheumatism. A method of isolation of hemocultures on Klodnitsky's medium with a 0.01% cystine can be recommended for the diagnosis of a septic condition caused by the L-forms of streptococcus in patients suffering from rheumatism.

Adolescent↗

PubMedDate not supplied

[Finding of anaerobic bacteria in blood cultures].

Out of the blood cultures sent to the Bacteriology Laboratory of Hospital del Niño DIF, during the period of one year, in 1.4% of samples, isolation of anaerobic bacteria was obtained. Isolation was more frequent in infants under one year of age, but specially in newborns. The species most frequently found were Propionibacterium acnes, Bacteroides melaninogenicus and Clostridium subterminale. The presence of this finding in blood cultures of infants is noted, but there is no purpose to establish a clinical relationship with the finding of this group of bacteria.

Adolescent↗

PubMed1978

Evaluation of twenty-three blood culture media.

Several investigators have evaluated clinically a variety of commercially available blood culture media. No agreement has been reached as to which of these media is optimal for detection of bacteremia. The purpose of this study was to determine the rate of recovery of microorganisms from various blood culture media. A total of 23 blood culture media were inoculated with 7 to 15 microorganisms per bottle in the presence or absence of an erythrocyte-serum mixture. The results demonstrated that blood culture media differed in their ability to support the growth of microorganisms. At 4 days after inoculation, only 10 of the 23 blood culture media supported the growth of 91% (10 of the 11) or more of the test microorganisms. The recovery rate of microorganisms depended not only upon the type of medium but also upon the manufacturer of the type of blood culture medium. The addition of an erythrocyte-serum mixture to the blood culture media did not influence the difference in the recovery rate of microorganisms among media and the same type of medium prepared by different manufacturers. The majority (15 of the 23) of the blood culture media supplemented with the erythrocyte-serum mixture failed to support the growth of 91% or more of the test microorganisms at 4 days after inoculation. These results have demonstrated that blood culture media need to be improved. Better quality control measures should also be implemented to evaluate commercial blood culture media.

Bacteria↗

PubMed2025

Whole-genome sequencing-based pathogen characterization for streptococcal infection directly from positive blood culture samples.

Clinical laboratories are increasingly using diagnostic tests directly on positive blood cultures, which may lead to fewer attempts to recover bacterial isolates. Consequently, public health laboratories can benefit from assays that directly process blood culture samples without requiring submission of clinical isolates to determine additional pathogen features not identified by clinical tests, such as vaccine serotype and bacterial genomic relatedness, for surveillance and outbreak response purposes. In partnership with the Minnesota Active Bacterial Core surveillance (ABCs) site, we identified blood culture samples positive for ABCs streptococcal pathogens and characterized them by a direct whole-genome sequencing from blood culture (dWGS) assay. The dWGS results were compared with the results of a reference method (WGS of isolates from the same cultures) to evaluate concordance in pathogen features and genome assemblies. Of the 97 eligible blood culture samples, 83 (86%) passed dWGS quality control criteria and were subjected to a total of 655 dWGS-based tests, which yielded 651 (99.3%) evaluable results. The percent agreement with reference results was 100% (83/83) for M protein gene (emm)/capsular types and 100% (81/81) for multilocus sequencing types. For genotypic antimicrobial susceptibility testing prediction, the percent prediction agreement was 100% (487/487), false resistant prediction rate was 0% (0/417), and the false susceptible prediction rate was 0% (0/66). Assemblies of pathogen genomes from the same patient differed by 1.08 ± 1.68 (mean ± SD) sites per genome. The dWGS assay can extract high-quality, important streptococcal strain characteristics directly from positive blood culture samples to support evolving public health needs.IMPORTANCEWhole-genome sequencing (WGS) technologies have emerged as a transformative toolkit used by public health microbiology laboratories to detect and characterize pathogens. The surveillance of bacterial diseases often relies on clinical laboratories to submit pathogen isolates to regional or national public health laboratories, which have the capacity to routinely conduct WGS-based strain characterization. Clinical laboratories are increasingly using diagnostic tests directly on positive blood cultures, which may lead to fewer attempts to recover bacterial isolates. The study evaluated a direct whole-genome sequencing from blood culture (dWGS) assay that directly processes blood culture samples. The dWGS assay recovered high quality, important streptococcal strain characteristics, including vaccine serotypes and whole-genome assemblies, without requiring submission of clinical isolates. Thus, the dWGS assay represents a promising tool for addressing the evolving needs of public health laboratories in the metagenomics era.

Humans↗

PubMed1979

Counterimmunoelectrophoresis for rapid identification of blood-culture isolates.

A total of 303 blood cultures that were positive by examination of Gram-stained smears were tested immediately by counterimmunoelectrophoresis for detection of bacterial antigens. Antigen was detected in all 82 blood cultures containing Streptococcus pneumoniae and 11 of 22 with Klebsiella pneumoniae, two of two with Haemophilus influenzae, and one of one with Neisseria meningiditis. False-positive cross-reactions in 265 tests occurred only with pneumococcal Omniserum in two cases of nongroupable streptococcal bacteremia and with Klebsiella antiserum in one case of Escherichia coli bacteremia (1.1%). A specific identification of the microorganisms at least 24 hours earlier than by subculture technics was accomplished in 91% of the cultures containing the aforementioned bacteria. The procedure was not useful for detecting antigen in blood cultures containing Staphylococcus aureus.

Antigens, Bacterial↗

PubMed1979

Radiometric detection of Haemophilus in simulated blood cultures.

The radiometric detection of various Haemophilus species was studied in simulated blood cultures and in blood culture media without added blood, but supplemented with nicotinamide-adenine dinucleotide (NAD) or hemin, or both. Haemophilus aphrophilus was the only species studied that was radiometrically detectable without added blood or NAD. All other species studied (Haemophilus influenzae, Haemophilus parainfluenzae, Haemophilus haemolyticus, and Haemophilus parahaemolyticus) required either added NAD, whole blood, or washed blood cells for growth and radiometric detection. The results of this study and extensive experience with clinical specimens show that the radiometric system is an effective means of rapidly detecting Haemophilus in blood cultures, but it is essential that it be used in conjunction with a subculture three to five days after inoculation.

Bacteriological Techniques↗

PubMed1975

Recovery of yeast from vented blood culture bottles.

Rates of isolation of yeasts from blood cultures were significantly enhanced by venting vacuum blood culture bottles in studies of both stimulated and patients' blood cultures; however, the time interval to detection of positivity of yeasts in the clinical studies was significantly (P less than 0.01) shorter in a vented bottle with biphasic brain heart infusion medium than in a vented bottle with soybean-casein digest broth. The mean time intervals to detection of positivity were 2.6 days in the former and 5.2 days in the latter.

Air↗

PubMed1977

A single-bottle blood culture system: evaluation and comparison with two other systems.

A commercially available single-bottle blood culture system was evaluated at Ben Taub General Hospital, a Harris County District Hospital. Blood cultures from 1010 patients were examined with the Lederle Diagnostics one-bottle blood culture medium-SPS, Columbia broth (E-Vac, Pfizer), and an in-house-prepared brain heart infusion broth with p-aminobenzoic acid (PABA) and 0.1% agar. Of the 1010 patients examined, blood cultures from 211 (20.8%) were positive, yielding a total of 23 different species of microorganisms. Comparison of the results during clinical evaluation, as well as those from simulated blood cultures, showed that the Lederle Diagnostics blood culture bottle was as effective as the in-house-prepared brain heart infusion and commercially available Columbia broths for isolation of aerobes as well as anaerobes. The techniques used in the evaluation and the advantages of a single-bottle culture system are discussed.

Aerobiosis↗

PubMed1977

Development of a lysis-filtration blood culture technique.

A lysed-blood culture system that quickly lyses patients' blood near neutrality and is relatively noninjurious to more delicate pathogens such as Haemophilus influenzae and Bacteroides fragilis is reported. The lysing solution includes culture medium, 0.004 M sodium carbonate and bicarbonate, 0.04% Triton X-100,and 0.6% Rhozyme (a mixture of proteases). Most of the pathogens tested multiplied in the lysing solution. The lysed blood normally is immediately filtered. The membrane is transferred to culture broth. The greatest advantage realized from this blood culture technique is separation of pathogens from antibiotics, bactericidal antibodies, complement, opsonins, and phagocytic systems. Another advantage is the concentration of organisms into a small volume of clear medium for faster growth and visualization of growth. It was observed that both gram-negative and -positive organisms were attracted during filtration to the filter material and were not removed from it by backwashing with buffer. Thus, filter membranes with porosities much larger than would nominally be expected to retain bacteria retained all or part of light and heavy Escherichia coli and Staphylococcus aureus suspensions. Advantage may be taken of this phenomenon to use filters with larger pore sizes and avoid filter clogging by poorly lysed specimens. Porr lysis may result from addition of too much blood to the lysing solution, blood with elevated numbers of erythrocytes or leukocytes, or blood from some people whose blood is naturally more resistant to lysis.

Bacteriological Techniques↗

PubMed1978

Disseminated Nocardia caviae with positive blood cultures.

Disseminated Nocardia caviae infection with multiple positive blood cultures occurred in a bone marrow transplant recipient. Positive blood cultures are unusual in disseminated Nocardia infections and N caviea is an unusual species of Nocardia to cause infections in man, although its virulence in laboratory animals is similar to N asteroides. Multiple positive blood cultures in this case suggest a continuous or recurrent bacteremia rather than a transient bacteremia as previously has been thought to occur in disseminated Nocardia infections. The marked immunosuppressed state of the patient and an indwelling venous line could also have accounted for the recurrent bacteremia.

Adult↗

PubMed1976

A gram stain for smears of blood cultures, body fluids and tissues.

A new Gram stain method for blood cultures was adapted from a method for tissue sections. This was accomplished by comparing various modifications of the latter method on positive smears prepared from a 24-hour negative blood culture seeded with Staphylococcus aureus and Escherichia coli. A blind study was then conducted using the new method and Hucker's method on 24-hour and 72-hour blood cultures as well as a limited number of other body fluids and tissues. Of the 35 positive blood cultures detected by the new method, the Hucker method failed to detect 14 positive specimens (40 per cent) upon initial examination. Ten additional cultures were negative using both stains, but were positive on subculture at three days. The 18 additional cultures positive after ten days were detected using only the Hucker stain.

Acinetobacter↗

PubMed1978

Isolation of Mycoplasma hominis from blood cultures in patients with postpartum fever.

Eight women with postpartum fever are presented in whom Mycoplasma hominis was isolated from cultures of their blood. Clinical disease consisted of a mild although often prolonged febrile illness, and all but one recovered without appropriate antimicrobial therapy. Five patients demonstrated elevated convalescent titers of mycoplasmacidal antibodies. The isolates of M. hominis were recovered from routine blood cultures in the diagnostic bacteriology laboratory using blind subcultures to blood agar plates. These cases lend support to the concept that endometritis with M. hominis is a cause of postpartum fever and suggest that these organisms may be recovered with increased frequency if minor changes in standard bacteriologic technique are introduced.

Bacteriological Techniques↗

PubMed1977

[Influence of the mode of collection on the result of blood cultures].

In a prospective study of 133 patients with suspicion of a septic process the influence of the withdrawal modus on the bacteriologic result was examined using an open blood culture system. For patients without pretreatment with antibiotics or without high temperature the "one time" withdrawal of the blood culture should be preferred to the "multi-time" method. A multi-time withdrawal showed similar and better evidence quotas with patients without fever and under influence of antibiotics. The result depends on the number of blood cultures for each patient. If there is presupposed a minimum of 2 positive blood cultures for each patient as indication of a septic process, a 83 per cent indication quota is attained with 12 one-time blood cultures, a 70 per cent indication quota with 8 blood cultures, and a 53 per cent indication quota with 4 blood cultures. In multi-time withdrawal the comparable indication quotas are 55, 45 resp. 32 per cent.

Anti-Bacterial Agents↗

PubMed1977

Interpretation of blood cultures yielding Staphylococcus aureus.

Forty-eight patients with blood cultures positive for Staphylococcus aureus were classified according to clinical criteria in three groups: "definite", "possible", and "doubtful" septicemia. Using traditional blood culture sets with two bottles (thioglycollate and tryptic soy broths), we found that patients with "definite" septicemia always showed more than one positive bottle per day if more than one set was drawn, that the mean detection time was 1.7 days, and that 95% of the first positive bottles and 92% of all positive bottles grew within two days of incubation. Patients with "doubtful" septicemia were more often (88%) positive in one bottle only, the mean detection time for all bottles was 3.7 days, and only 35% of the first positive bottles and 33% of all positive bottles yielded growth within two days. "Possible" cases took a position between these two extremes but tended more towards the "doubtful" cases. The implications of these findings for the interpretation of blood cultures with S. aureus are discussed.

Blood↗