Diagnostic Microbiology and Infectious Disease, Mar 1, 1986
Screening tests have had a major role in the diagnostic microbiology laboratory during recent yea... more Screening tests have had a major role in the diagnostic microbiology laboratory during recent years. Many factors have contributed to the increased use of these methods. The primary factor is the need for rapid detection and identification of the etiologic agent in life-threatening infections, which include bacterial meningitis, infective endocarditis and septicemia, and pneumonia. Various direct screening methods are also available for eliminating negative specimens rapidly. These methods have had an impact on laboratory work flow and the outpatient population by eliminating the possibility of bacterial infections of the urinary, upper respiratory, and gastrointestinal tracts. Screening methods have also been applied to isolated colonies for the rapid differentiation and identification of certain groups of organisms. Finally, many of these screening methods have contributed to cost-savings for both the laboratory and the patient. In this era of prospective pricing, and until the entrance of biotechnology into the diagnostic microbiology laboratory, the microbiologist must rely upon these rapid, inexpensive screening procedures. The role of these screening tests in the diagnostic microbiology laboratory and their impact on patient care and cost are reviewed herein.
A study was performed to determine the ability of an investigational, rapid, optical analysis sys... more A study was performed to determine the ability of an investigational, rapid, optical analysis system to detect, classify, quantify and identify urinary pathogens. POCARED Rapid Diagnostic System (RDS, POCARED Diagnostics LTD.) is an automated system that employs advanced fluorescence, optical data analysis and artificial intelligence methods to analyze multi-dimensional optical characteristics of clinical specimens and identify pathogenic organisms. It captures the emitted light from the interaction between photons and molecules to detect the pathogens’ unique optical properties and subsequently an algorithm determines the results. The purpose was to evaluate POCARED’s RDS ability to detect, classify, quantify, and identify Escherichia coli (Ec), Klebsiella pneumoniae (Kp), Enterobacter cloacae (Eb), Proteus mirabilis (Pm), Pseudomonas aeruginosa (Pa), Staphylococcus saprophyticus (Ss), Enterococcus faecalis (Ef) and Candida albicans (Ca) when compared with the standard plate cultur...
"The Color Atlas of Medical Bacteriology" is a compilation of exceptional four color im... more "The Color Atlas of Medical Bacteriology" is a compilation of exceptional four color images of important bacteria in medical microbiology. Drawing on their own classroom and laboratory experiences, the authors have organized a collection of over 650 superb photographs, almost all of which are original to this volume and representative of clinically relevant organisms. This easy-to-use atlas presents illustrations of the bacteria most frequently encountered in the clinical laboratory, including typical Gram stains, colony morphologies, and biochemical reactions. Each chapter begins with a brief introduction, providing a contextual framework for the images, with the last chapter detailing some of the most common methods and biochemical reactions used in the identification of pathogenic bacteria. A representative sampling of certain bacteria with unique or interesting pictorial characteristics is presented, and terminology current to the discipline is used throughout. The organization of the atlas closely parallels that of the "Manual of Clinical Microbiology", making it a perfect companion reference. Filling a void that most textbooks on the subject cannot, the "Color Atlas of Medical Bacteriology" is a valuable illustrative supplement for lectures and laboratory presentations. Key features of this title are as mentioned below. It presents over 650 four-color illustrations of important bacteria, focusing on representative characteristics of the organisms. It contains superior quality photographs, most taken specifically for this edition. Its organization parallels that of the "Manual of Clinical Microbiology", making it a perfect companion reference. It draws on the extensive experience of the authors in determining illustrations that are commonly used in the teaching of microbiology.
Intrauterine specimens were obtained from 22 patients with endometritis and 24 control patients f... more Intrauterine specimens were obtained from 22 patients with endometritis and 24 control patients following cesarean section by using both a new protected swab and a standard anaerobic swab. The protected swab improved the value of the direct smear and Gram stain, resulted in fewer false-positive cultures, better defined endometrial flora in patients with endometritis, and permitted major savings in laboratory personnel time and materials.
Blood cultures collected in BACTEC Plus Aerobic/F bottles and BACTEC Plus Anaerobic/F bottles wer... more Blood cultures collected in BACTEC Plus Aerobic/F bottles and BACTEC Plus Anaerobic/F bottles were monitored for 5 days by BACTEC 9240 and subsequent terminal subcultures. Of the 13,471 bottles subcultured, 11.0% (1,477 of 13,471) were culture positive. Of these, 94.0% (1,388 of 1,477) were detected by BACTEC 9240; the additional 6.0% (89 of 1,477) were considered to be false negatives by BACTEC 9240 since they were detected by terminal subculture only. The false-negative bottles consisted of 17 BACTEC Plus Aerobic/F and 72 BACTEC Plus Anaerobic/F bottles, accounting for 2.2 (17 of 786) and 10.4% (72 of 691) of the total positive aerobic and anaerobic bottles, respectively. The positive blood culture bottles most frequently not detected by BACTEC 9240 grew Pseudomonas spp. (24), Staphylococcus spp. (21), and yeasts (24). Of the 86 blood cultures represented by the 89 false-negative bottles, 41 would not have been identified as positive since the other bottle in the blood culture set...
Two systems, the Identicult-Neisseria (IDN; Scott Laboratories, Inc., Fiskeville, R.I.) strip and... more Two systems, the Identicult-Neisseria (IDN; Scott Laboratories, Inc., Fiskeville, R.I.) strip and the Neisseria/Haemophilus Identification Test Kit (NHI; Vitek Systems, Inc., Hazelwood, Mo.) card, were compared with the 4-h Minitek system (BBL Microbiology Systems, Cockeysville, Md.) for their ability to rapidly identify 157 pathogenic Neisseria and Branhamella catarrhalis isolates. IDN, limited in its identification to four species, when incubated at 35 degrees C for 10 min identified 99% of the isolates. However, when IDN was incubated at 22 degrees C for 20 min, it identified only 92% of the isolates. The NHI card, a rapid semiautomated system with the ability to identify 25 organisms to the species level, correctly identified all of the isolates. A test for beta-lactamase production included in the NHI card identified the 12 Neisseria gonorrhoeae and 10 B. catarrhalis beta-lactamase-positive isolates included in the study. The IDN strip (35 degrees C) and the NHI card compared f...
A study was conducted to compare three automated systems and the Gram stain for their ability to ... more A study was conducted to compare three automated systems and the Gram stain for their ability to detect significant bacteriuria. A total of 1,000 urine specimens were evaluated by Autobac MTS (General Diagnostics), Auto Microbic system (AMS; Vitek Systems, Inc.), and MS-2 (Abbott Laboratories) and compared with a semiquantitative culture plate method. Two hundred thirty-nine (23.9%) specimens had colony counts of >10 5 colony-forming units (CFU)/ml by the culture plate method (group I). Of these, 204 (85.3%) were positive by Autobac, 198 (82.8%) were positive by AMS, and 179 (74.9%) were positive by MS-2. When pure cultures of diphtheroids, lactobacilli, and viridans streptococci not group D were considered contaminants and therefore excluded, there were 118 specimens containing pure cultures of probable pathogens. The percentage of significant isolates detected was 97.4% (115 of 118) by the Gram stain, 96.6% (114 of 118) by Autobac, and 95.8% (113 of 118) by AMS and MS-2. The av...
The effect of urine collected in the B-D Urine Culture Kit (BDT; Becton, Dickinson & Co., Rutherf... more The effect of urine collected in the B-D Urine Culture Kit (BDT; Becton, Dickinson & Co., Rutherford, N.J.) on the Autobac urine screen (General Diagnostics, Warner-Lambert Co., Morris Plains, N.J.) was investigated. Upon collection, 1,000 clean-voided urine specimens were divided into sterile urine tubes and BDTs. Within 24 h of collection, urine from each tube was cultured by a semiquantitative plate method and screened by the Autobac system. Overall, when screened by the Autobac system, urine collected in the BDT gave fewer false-positive results: 14.4 compared with 22.7% from the sterile urine tubes. However, in comparison with the sterile urine tubes, the BDT false-negative rate was 10.5 versus 4.7%, the detection time was longer, and the cost was increased.
A study was conducted to evaluate the ability of a urine filtration system (Bac-T-Screen, Marion ... more A study was conducted to evaluate the ability of a urine filtration system (Bac-T-Screen, Marion Laboratories, Inc., Kansas City, Mo.) to detect negative urine cultures within 2 min. A total of 1,000 urine specimens were tested with the Bac-T-Screen and compared with a standard semiquantitative culture plate method and the Autobac system (General Diagnostics, Warner-Lambert Co., Morris Plains, N.J.). Of the 1,000 clean voided urine specimens tested, 246 specimens had colony counts greater than or equal to 10(5) CFU/ml by the culture plate method. Of these, the Bac-T-Screen detected 65.4% (161 of 246), and the Autobac detected 63.0% (155 of 246). When pure cultures of diphtheroids, lactobacilli, and viridans streptococci other than group D and cultures containing multiple organisms were considered to be contaminants and, therefore, were excluded, there were 106 pure cultures of probable pathogens of which the Bac-T-Screen detected 76.4% (81 of 106) and the Autobac detected 90.6% (96 ...
Urine cultures represent 40-50% of specimens processed by hospital clinical microbiology laborato... more Urine cultures represent 40-50% of specimens processed by hospital clinical microbiology laboratories. An accurate rapid screening method to detect positive urine cultures could greatly improve laboratory efficiency. Three hundred eighty-two unselected urines were screened by nephelometry at 2, 4, and 5 hours of shaking and incubation in Autobac cuvettes. Results were compared in parallel with standard quantitative-loop plate cultures of the same specimens. Fifty-eight of the 382 specimens showed significant positive (greater than or equal to 10(5) CFU/ml) standard plate cultures. Fifty-four of the 58 were positive at 4 hours by the nephelometric method (sensitivity 93%, 7% false negatives). Plate cultures of the four false negative specimens grew greater than 10(5) CFU/ml Candida (two specimens), Staphylococcus epidermidis or diphtheroids (one specimen each) and represented colonization or contamination without evidence of infection. For 324 specimens negative by plate culture, nephelometry was negative in 287 (89% specificity or 11% false positives). Overall predictive value of a negative test was 99%. Results were comparable for clean-voided or catheterized specimens. The rapid nephelometric urine culture method gave significant savings of material and time.
A 42-year-old man had an infected ulcerated lesion of the anterior aspect of the right lower extr... more A 42-year-old man had an infected ulcerated lesion of the anterior aspect of the right lower extremity. Vibrio alginolyticus was twice isolated from the lesion. Emphasis is placed on the clinical and laboratory characteristics of this organism and its differentiation from other halophilic vibrios.
Seven automated bacteriuria screening methods are currently available for clinical use. Three are... more Seven automated bacteriuria screening methods are currently available for clinical use. Three are based on the principle of photometry: the Autobac Systema, the AutoMicrobic Systemb, and the MS-2c. Three utilize bioluminescence: the Lumacd, Monolight 2001e, and Turner Luminometerf. One method is based on colorimetry and filtration: Bac-T-Screeng. Detection times for these systems range from two minutes to nine hours. This article reviews these systems with regard to sensitivity, predictive value, detection time, and cost.
Diagnostic Microbiology and Infectious Disease, Mar 1, 1986
Screening tests have had a major role in the diagnostic microbiology laboratory during recent yea... more Screening tests have had a major role in the diagnostic microbiology laboratory during recent years. Many factors have contributed to the increased use of these methods. The primary factor is the need for rapid detection and identification of the etiologic agent in life-threatening infections, which include bacterial meningitis, infective endocarditis and septicemia, and pneumonia. Various direct screening methods are also available for eliminating negative specimens rapidly. These methods have had an impact on laboratory work flow and the outpatient population by eliminating the possibility of bacterial infections of the urinary, upper respiratory, and gastrointestinal tracts. Screening methods have also been applied to isolated colonies for the rapid differentiation and identification of certain groups of organisms. Finally, many of these screening methods have contributed to cost-savings for both the laboratory and the patient. In this era of prospective pricing, and until the entrance of biotechnology into the diagnostic microbiology laboratory, the microbiologist must rely upon these rapid, inexpensive screening procedures. The role of these screening tests in the diagnostic microbiology laboratory and their impact on patient care and cost are reviewed herein.
A study was performed to determine the ability of an investigational, rapid, optical analysis sys... more A study was performed to determine the ability of an investigational, rapid, optical analysis system to detect, classify, quantify and identify urinary pathogens. POCARED Rapid Diagnostic System (RDS, POCARED Diagnostics LTD.) is an automated system that employs advanced fluorescence, optical data analysis and artificial intelligence methods to analyze multi-dimensional optical characteristics of clinical specimens and identify pathogenic organisms. It captures the emitted light from the interaction between photons and molecules to detect the pathogens’ unique optical properties and subsequently an algorithm determines the results. The purpose was to evaluate POCARED’s RDS ability to detect, classify, quantify, and identify Escherichia coli (Ec), Klebsiella pneumoniae (Kp), Enterobacter cloacae (Eb), Proteus mirabilis (Pm), Pseudomonas aeruginosa (Pa), Staphylococcus saprophyticus (Ss), Enterococcus faecalis (Ef) and Candida albicans (Ca) when compared with the standard plate cultur...
"The Color Atlas of Medical Bacteriology" is a compilation of exceptional four color im... more "The Color Atlas of Medical Bacteriology" is a compilation of exceptional four color images of important bacteria in medical microbiology. Drawing on their own classroom and laboratory experiences, the authors have organized a collection of over 650 superb photographs, almost all of which are original to this volume and representative of clinically relevant organisms. This easy-to-use atlas presents illustrations of the bacteria most frequently encountered in the clinical laboratory, including typical Gram stains, colony morphologies, and biochemical reactions. Each chapter begins with a brief introduction, providing a contextual framework for the images, with the last chapter detailing some of the most common methods and biochemical reactions used in the identification of pathogenic bacteria. A representative sampling of certain bacteria with unique or interesting pictorial characteristics is presented, and terminology current to the discipline is used throughout. The organization of the atlas closely parallels that of the "Manual of Clinical Microbiology", making it a perfect companion reference. Filling a void that most textbooks on the subject cannot, the "Color Atlas of Medical Bacteriology" is a valuable illustrative supplement for lectures and laboratory presentations. Key features of this title are as mentioned below. It presents over 650 four-color illustrations of important bacteria, focusing on representative characteristics of the organisms. It contains superior quality photographs, most taken specifically for this edition. Its organization parallels that of the "Manual of Clinical Microbiology", making it a perfect companion reference. It draws on the extensive experience of the authors in determining illustrations that are commonly used in the teaching of microbiology.
Intrauterine specimens were obtained from 22 patients with endometritis and 24 control patients f... more Intrauterine specimens were obtained from 22 patients with endometritis and 24 control patients following cesarean section by using both a new protected swab and a standard anaerobic swab. The protected swab improved the value of the direct smear and Gram stain, resulted in fewer false-positive cultures, better defined endometrial flora in patients with endometritis, and permitted major savings in laboratory personnel time and materials.
Blood cultures collected in BACTEC Plus Aerobic/F bottles and BACTEC Plus Anaerobic/F bottles wer... more Blood cultures collected in BACTEC Plus Aerobic/F bottles and BACTEC Plus Anaerobic/F bottles were monitored for 5 days by BACTEC 9240 and subsequent terminal subcultures. Of the 13,471 bottles subcultured, 11.0% (1,477 of 13,471) were culture positive. Of these, 94.0% (1,388 of 1,477) were detected by BACTEC 9240; the additional 6.0% (89 of 1,477) were considered to be false negatives by BACTEC 9240 since they were detected by terminal subculture only. The false-negative bottles consisted of 17 BACTEC Plus Aerobic/F and 72 BACTEC Plus Anaerobic/F bottles, accounting for 2.2 (17 of 786) and 10.4% (72 of 691) of the total positive aerobic and anaerobic bottles, respectively. The positive blood culture bottles most frequently not detected by BACTEC 9240 grew Pseudomonas spp. (24), Staphylococcus spp. (21), and yeasts (24). Of the 86 blood cultures represented by the 89 false-negative bottles, 41 would not have been identified as positive since the other bottle in the blood culture set...
Two systems, the Identicult-Neisseria (IDN; Scott Laboratories, Inc., Fiskeville, R.I.) strip and... more Two systems, the Identicult-Neisseria (IDN; Scott Laboratories, Inc., Fiskeville, R.I.) strip and the Neisseria/Haemophilus Identification Test Kit (NHI; Vitek Systems, Inc., Hazelwood, Mo.) card, were compared with the 4-h Minitek system (BBL Microbiology Systems, Cockeysville, Md.) for their ability to rapidly identify 157 pathogenic Neisseria and Branhamella catarrhalis isolates. IDN, limited in its identification to four species, when incubated at 35 degrees C for 10 min identified 99% of the isolates. However, when IDN was incubated at 22 degrees C for 20 min, it identified only 92% of the isolates. The NHI card, a rapid semiautomated system with the ability to identify 25 organisms to the species level, correctly identified all of the isolates. A test for beta-lactamase production included in the NHI card identified the 12 Neisseria gonorrhoeae and 10 B. catarrhalis beta-lactamase-positive isolates included in the study. The IDN strip (35 degrees C) and the NHI card compared f...
A study was conducted to compare three automated systems and the Gram stain for their ability to ... more A study was conducted to compare three automated systems and the Gram stain for their ability to detect significant bacteriuria. A total of 1,000 urine specimens were evaluated by Autobac MTS (General Diagnostics), Auto Microbic system (AMS; Vitek Systems, Inc.), and MS-2 (Abbott Laboratories) and compared with a semiquantitative culture plate method. Two hundred thirty-nine (23.9%) specimens had colony counts of >10 5 colony-forming units (CFU)/ml by the culture plate method (group I). Of these, 204 (85.3%) were positive by Autobac, 198 (82.8%) were positive by AMS, and 179 (74.9%) were positive by MS-2. When pure cultures of diphtheroids, lactobacilli, and viridans streptococci not group D were considered contaminants and therefore excluded, there were 118 specimens containing pure cultures of probable pathogens. The percentage of significant isolates detected was 97.4% (115 of 118) by the Gram stain, 96.6% (114 of 118) by Autobac, and 95.8% (113 of 118) by AMS and MS-2. The av...
The effect of urine collected in the B-D Urine Culture Kit (BDT; Becton, Dickinson & Co., Rutherf... more The effect of urine collected in the B-D Urine Culture Kit (BDT; Becton, Dickinson & Co., Rutherford, N.J.) on the Autobac urine screen (General Diagnostics, Warner-Lambert Co., Morris Plains, N.J.) was investigated. Upon collection, 1,000 clean-voided urine specimens were divided into sterile urine tubes and BDTs. Within 24 h of collection, urine from each tube was cultured by a semiquantitative plate method and screened by the Autobac system. Overall, when screened by the Autobac system, urine collected in the BDT gave fewer false-positive results: 14.4 compared with 22.7% from the sterile urine tubes. However, in comparison with the sterile urine tubes, the BDT false-negative rate was 10.5 versus 4.7%, the detection time was longer, and the cost was increased.
A study was conducted to evaluate the ability of a urine filtration system (Bac-T-Screen, Marion ... more A study was conducted to evaluate the ability of a urine filtration system (Bac-T-Screen, Marion Laboratories, Inc., Kansas City, Mo.) to detect negative urine cultures within 2 min. A total of 1,000 urine specimens were tested with the Bac-T-Screen and compared with a standard semiquantitative culture plate method and the Autobac system (General Diagnostics, Warner-Lambert Co., Morris Plains, N.J.). Of the 1,000 clean voided urine specimens tested, 246 specimens had colony counts greater than or equal to 10(5) CFU/ml by the culture plate method. Of these, the Bac-T-Screen detected 65.4% (161 of 246), and the Autobac detected 63.0% (155 of 246). When pure cultures of diphtheroids, lactobacilli, and viridans streptococci other than group D and cultures containing multiple organisms were considered to be contaminants and, therefore, were excluded, there were 106 pure cultures of probable pathogens of which the Bac-T-Screen detected 76.4% (81 of 106) and the Autobac detected 90.6% (96 ...
Urine cultures represent 40-50% of specimens processed by hospital clinical microbiology laborato... more Urine cultures represent 40-50% of specimens processed by hospital clinical microbiology laboratories. An accurate rapid screening method to detect positive urine cultures could greatly improve laboratory efficiency. Three hundred eighty-two unselected urines were screened by nephelometry at 2, 4, and 5 hours of shaking and incubation in Autobac cuvettes. Results were compared in parallel with standard quantitative-loop plate cultures of the same specimens. Fifty-eight of the 382 specimens showed significant positive (greater than or equal to 10(5) CFU/ml) standard plate cultures. Fifty-four of the 58 were positive at 4 hours by the nephelometric method (sensitivity 93%, 7% false negatives). Plate cultures of the four false negative specimens grew greater than 10(5) CFU/ml Candida (two specimens), Staphylococcus epidermidis or diphtheroids (one specimen each) and represented colonization or contamination without evidence of infection. For 324 specimens negative by plate culture, nephelometry was negative in 287 (89% specificity or 11% false positives). Overall predictive value of a negative test was 99%. Results were comparable for clean-voided or catheterized specimens. The rapid nephelometric urine culture method gave significant savings of material and time.
A 42-year-old man had an infected ulcerated lesion of the anterior aspect of the right lower extr... more A 42-year-old man had an infected ulcerated lesion of the anterior aspect of the right lower extremity. Vibrio alginolyticus was twice isolated from the lesion. Emphasis is placed on the clinical and laboratory characteristics of this organism and its differentiation from other halophilic vibrios.
Seven automated bacteriuria screening methods are currently available for clinical use. Three are... more Seven automated bacteriuria screening methods are currently available for clinical use. Three are based on the principle of photometry: the Autobac Systema, the AutoMicrobic Systemb, and the MS-2c. Three utilize bioluminescence: the Lumacd, Monolight 2001e, and Turner Luminometerf. One method is based on colorimetry and filtration: Bac-T-Screeng. Detection times for these systems range from two minutes to nine hours. This article reviews these systems with regard to sensitivity, predictive value, detection time, and cost.
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