Letters to the Editor Toxoplasmosis
Received September 18, 1974; accepted for publication September 18, 1975. Key words: Toxoplasmosis.
1. dos Santos, Neto, JG: Toxoplasmosis. A historical review, direct diagnostic microscopy, and report of a case. Am J Clin Pathol 63:909-915, 1975
Dipslide Urine Cultures To the Editor:—Our laboratory has had considerable experience with dipslide urine cultures, so the recent article by Ellner and Papachristos 4 was read with interest. It is suggested in their paper that dipslides could be used to reduce costs by making it unnecessary for laboratory personnel to plate urine specimens. We have found the price we must pay for dipslides to exceed that of conventional prepared media so greatly that the net result of simple substitution of the former for the latter in our laboratory would be increased costs. Nevertheless, we agree that, at least under some circumstances, dipslides can be used cost-effectively. If they are incubated at the office, clinic or ward where the specimen is obtained and screened for positive results Received J u n e 20, 1975; accepted for publication August 4, 1975. Key words: Urinary tract infections; Bacteriologic technics. 250
by physicians or paramedical personnel, savings can be made in secretarial and transportation costs as well as in plating. No special equipment is required by those who choose to screen their own cultures. As cited by Ellner and Papachristos, a previous study has shown that incubation at room temperature is adequate for the detection of Gram-negative bacilli. 1 Preliminary studies here have shown that enterococci, staphylococci and yeasts can also be detected upon incubation at 2 0 - 2 5 C. if the dipslides are kept for 48 hours before being read. Those who follow this procedure will of course have to submit suspicious or positive cultures to the laboratory for evaluation and work-up, but negative results are available immediately without need for reliance on mails, hospital messenger service, or laboratory record keeping. We have experienced several difficulties in using dipslides that were not mentioned
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To the Editor:—Upon receiving a reprint Nevertheless, it behooves me to state the of my paper on toxoplasmosis, 1 Dr. J. K. Doctor Frenkel described such a case in Frenkel wrote to me: "It is funny that I 1951, and the complete reference for those probably forgot to mention to you, but I interested is Public Health Service Publicaremembered when I saw your reprint that tion No. 141-1951, by J. K. Frenkel and S. we also found Toxoplasma in the ventricu- Friedlander, 105 pages—28 plates. lar fluid of a baby; I am sending a Xerox copy of pp. 16-17 of PHS Publication 141 JOAO GUSTAVO DOS SANTOS, N E T O , M.D. published in 1951." Medical College of Virginia PHS Publication 141 was not read beVirginia Commonwealth University cause our Medical Library did not have it, MCV Station but mainly because the abstract publications Richmond, Virginia 23298 (Tropical Disease Bulletin and Biological Abstracts) did not imply the publication dealt with direct microscopic detection of ToxoReferences plasma.
February 1976
251
LETTERS T O T H E EDITOR
In summary, we have found dipslides to be extremely useful in screening out negative cultures, and we think that they can be used cost-effectively if checked for positivity at the place of culture. We have found them to be inferior to agar plates when
significant bacteriuria is present. Their optimum use is in situations where the expected percentages of positive cultures are low. We would recommend their use, for example, in screening cultures for asymptomatic bacteriuria in obstetric patients and in follow-up cultures from cases of patients with treated urinary-tract infections. SAMUEL L. ROSENTHAL, M.D. LAWRENCE F. FREUNDLICH, M.S.
Department of Laboratory Medicine Albert Einstein College of Medicine and Bronx Municipal Hospital Center Bronx, New York 10461 References 1. Arnei) GC, McAllister TA, Kay P: Detection of bacteriuria at room temperature. Lancet 1:119-121, 1970 2. Bauer AW, Kirby WMM, Sherris JC, et al: Antibiotic susceptibility testing by a standardized single disk method. Am J Clin Pathol 45:493-496, 1966 3. Edwards PR, Ewing WH: Isolation and preliminary identification, Identification of Enterobacteriaceae. Third edition. Minneapolis, Burgess Publishing Co., 1972, chapter 2 4. Ellner PD, Papachristos T: Detection of bacteriuria by dip-slide. Am J Clin Pathol 63:516521, 1975
Dr. Ellner's Reply To the Editor:—We cannot agree with Dr. Rosenthal and Freundlich that the substitution of dipslides for conventional media would result in increased costs. Two plates of prepared media (EMB and CNA) as purchased from Scott Laboratories Inc., currently cost us 50 cents. The plastic tube (a Falcon product) costs 8.7 cents. Technician time for plating averages 0.93 minutes, which at 10.5 cents per minute comes to 9.8 cents per specimen. Thus, the total cost for processing a specimen by conventional Received August 4, 1975; accepted for publication August 4, 1975.
means totals 68.5 cents. T h e Uricult dipslide presently costs 45 cents each. We also disagree that confluent growth on the dipslide may be confused with the absence of growth; confluent growth is easily recognized by inspection under adequate illumination. Growth is often accompanied by the characteristic odors familiar to clinical microbiologists. There is no reason why dipslides cannot be incubated at the office, clinic, or ward where the specimen is obtained, and screened for positive results by physicians, nurses, or other paramedical personnel. Thus, negative results would be im-
Downloaded from http://ajcp.oxfordjournals.org/ by guest on June 8, 2016
by Ellner and Papachristos. These have occurred mainly when cultures have been bacteriologically positive. When colony counts are high, growth on the agar surfaces may be confluent. Confluent growth can be easily mistaken for absence of growth if the dipslides are not examined carefully. If there is heavy growth it may be impossible to tell on inspection whether a pure or a mixed culture is present. Colonial morphology is not distinct on CLEDcolistin agar, and subculture is always necessary for interpretation if significant growth on that part of the dipslide is suspected. Moreover, almost every positive dipslide must be subcultured, since accepted procedures for species identification and antibiotic sensitivity testing require that tests be performed on well-isolated representative colonies. 2,3 Final reports on positive cultures are thus usually delayed 24 hours.
Received September 18, 1974; accepted for publication September 18, 1975. Key words: Toxoplasmosis.
1. dos Santos, Neto, JG: Toxoplasmosis. A historical review, direct diagnostic microscopy, and report of a case. Am J Clin Pathol 63:909-915, 1975
Dipslide Urine Cultures To the Editor:—Our laboratory has had considerable experience with dipslide urine cultures, so the recent article by Ellner and Papachristos 4 was read with interest. It is suggested in their paper that dipslides could be used to reduce costs by making it unnecessary for laboratory personnel to plate urine specimens. We have found the price we must pay for dipslides to exceed that of conventional prepared media so greatly that the net result of simple substitution of the former for the latter in our laboratory would be increased costs. Nevertheless, we agree that, at least under some circumstances, dipslides can be used cost-effectively. If they are incubated at the office, clinic or ward where the specimen is obtained and screened for positive results Received J u n e 20, 1975; accepted for publication August 4, 1975. Key words: Urinary tract infections; Bacteriologic technics. 250
by physicians or paramedical personnel, savings can be made in secretarial and transportation costs as well as in plating. No special equipment is required by those who choose to screen their own cultures. As cited by Ellner and Papachristos, a previous study has shown that incubation at room temperature is adequate for the detection of Gram-negative bacilli. 1 Preliminary studies here have shown that enterococci, staphylococci and yeasts can also be detected upon incubation at 2 0 - 2 5 C. if the dipslides are kept for 48 hours before being read. Those who follow this procedure will of course have to submit suspicious or positive cultures to the laboratory for evaluation and work-up, but negative results are available immediately without need for reliance on mails, hospital messenger service, or laboratory record keeping. We have experienced several difficulties in using dipslides that were not mentioned
Downloaded from http://ajcp.oxfordjournals.org/ by guest on June 8, 2016
To the Editor:—Upon receiving a reprint Nevertheless, it behooves me to state the of my paper on toxoplasmosis, 1 Dr. J. K. Doctor Frenkel described such a case in Frenkel wrote to me: "It is funny that I 1951, and the complete reference for those probably forgot to mention to you, but I interested is Public Health Service Publicaremembered when I saw your reprint that tion No. 141-1951, by J. K. Frenkel and S. we also found Toxoplasma in the ventricu- Friedlander, 105 pages—28 plates. lar fluid of a baby; I am sending a Xerox copy of pp. 16-17 of PHS Publication 141 JOAO GUSTAVO DOS SANTOS, N E T O , M.D. published in 1951." Medical College of Virginia PHS Publication 141 was not read beVirginia Commonwealth University cause our Medical Library did not have it, MCV Station but mainly because the abstract publications Richmond, Virginia 23298 (Tropical Disease Bulletin and Biological Abstracts) did not imply the publication dealt with direct microscopic detection of ToxoReferences plasma.
February 1976
251
LETTERS T O T H E EDITOR
In summary, we have found dipslides to be extremely useful in screening out negative cultures, and we think that they can be used cost-effectively if checked for positivity at the place of culture. We have found them to be inferior to agar plates when
significant bacteriuria is present. Their optimum use is in situations where the expected percentages of positive cultures are low. We would recommend their use, for example, in screening cultures for asymptomatic bacteriuria in obstetric patients and in follow-up cultures from cases of patients with treated urinary-tract infections. SAMUEL L. ROSENTHAL, M.D. LAWRENCE F. FREUNDLICH, M.S.
Department of Laboratory Medicine Albert Einstein College of Medicine and Bronx Municipal Hospital Center Bronx, New York 10461 References 1. Arnei) GC, McAllister TA, Kay P: Detection of bacteriuria at room temperature. Lancet 1:119-121, 1970 2. Bauer AW, Kirby WMM, Sherris JC, et al: Antibiotic susceptibility testing by a standardized single disk method. Am J Clin Pathol 45:493-496, 1966 3. Edwards PR, Ewing WH: Isolation and preliminary identification, Identification of Enterobacteriaceae. Third edition. Minneapolis, Burgess Publishing Co., 1972, chapter 2 4. Ellner PD, Papachristos T: Detection of bacteriuria by dip-slide. Am J Clin Pathol 63:516521, 1975
Dr. Ellner's Reply To the Editor:—We cannot agree with Dr. Rosenthal and Freundlich that the substitution of dipslides for conventional media would result in increased costs. Two plates of prepared media (EMB and CNA) as purchased from Scott Laboratories Inc., currently cost us 50 cents. The plastic tube (a Falcon product) costs 8.7 cents. Technician time for plating averages 0.93 minutes, which at 10.5 cents per minute comes to 9.8 cents per specimen. Thus, the total cost for processing a specimen by conventional Received August 4, 1975; accepted for publication August 4, 1975.
means totals 68.5 cents. T h e Uricult dipslide presently costs 45 cents each. We also disagree that confluent growth on the dipslide may be confused with the absence of growth; confluent growth is easily recognized by inspection under adequate illumination. Growth is often accompanied by the characteristic odors familiar to clinical microbiologists. There is no reason why dipslides cannot be incubated at the office, clinic, or ward where the specimen is obtained, and screened for positive results by physicians, nurses, or other paramedical personnel. Thus, negative results would be im-
Downloaded from http://ajcp.oxfordjournals.org/ by guest on June 8, 2016
by Ellner and Papachristos. These have occurred mainly when cultures have been bacteriologically positive. When colony counts are high, growth on the agar surfaces may be confluent. Confluent growth can be easily mistaken for absence of growth if the dipslides are not examined carefully. If there is heavy growth it may be impossible to tell on inspection whether a pure or a mixed culture is present. Colonial morphology is not distinct on CLEDcolistin agar, and subculture is always necessary for interpretation if significant growth on that part of the dipslide is suspected. Moreover, almost every positive dipslide must be subcultured, since accepted procedures for species identification and antibiotic sensitivity testing require that tests be performed on well-isolated representative colonies. 2,3 Final reports on positive cultures are thus usually delayed 24 hours.
