1048
Correspondence
Julie L. Steiner, Edward J. Septimus, and Carl V. Vartian Program in Infectious Diseases, Memorial Healthcare System, University of Texas Medical School, Houston, Texas
References 1. Bresee J, Edwards M. Psoas abscess in children. Pediatr Infect Dis J 1990;9:201-6. 2. Ricci M, Rose F, Meyer K. Pyogenic psoas abscess: worldwide variations in etiology. World J Surg 1986;10:834-43. 3. Leu SY, Leonard MB, Beart RW Jr, Dozois R. Psoas abscess: changing patterns ofdiagnosis and etiology. Dis Colon Rectum 1986;29:694-8.
SIR-The State-of-the-Art Clinical Article in the April issue of Clinical Infectious Diseases [1] has an ambiguous statement that the readership should note. Dr. Musher commented, ". . . sputum specimens must contain areas with at least 15-20 WBCs [white blood cells] and no epithelial cells in a standard microscopic field under Xl ,000 magnification. If sufficient numbers of inflammatory cells are not present, the specimen material is inappropriate." When a sputum gram stain is examined at Xl ,000 magnifica-
4. Kyle J. Psoas abscess in Crohn's disease. Gastroenterology 1971; 61:149-55. 5. Musher D. Infections caused by Streptococcus pneumoniae: clinical spectrum, pathogenesis, immunity, and treatment. Clin Infect Dis 1992; 14:80 1-9. 6. DiNubile M Jr, Albornoz MA, Stumacher RJ, et al. Pneumococcal softtissue infections: possible association with connective tissue diseases. J Infect Dis 1991;163:897-900. 7. Levine JF, Hiesiger EM, Whelan MA, et al. Pneumococcal meningitis associated with retroperitoneal abscess. A rare complication oflumbar puncture. JAMA 1982;248:2308-9. 8. Scott B, Schmidt J. Pneumococcal meningitis due to psoas abscess. South Med J 1989;82: 1310-1.
tion, an unreliable specimen could be misinterpreted if no epithelial cells are seen. On the other hand, a reliable specimen may be labeled unreliable if an epithelial cell is seen. Current standards for sputum evaluation [2] require that gram-stained slides be first examined at low-power field (X 100); specimens are considered reliable if < I0 epithelial cells and>25 WBCs are present. The examiner may then switch to X1,000 magnification for further study of the slide and presumptive identification of pathogens. Sary O. Beidas William A. Davis Clinic, St. Paul, Virginia
References Correspondence: Dr. Sary O. Beidas, ARH Wm. Davis Clinic, 63 North Drawer T, St. Paul, Virginia 24283. Clinical Infectious Diseases 1992;15:1048 © 1992 by The University of Chicago. All rights reserved. 1058-4838/92/1506-0020$02.00
Reply SIR-I thank Dr. Beidas for his comments on the sputum gram stain. Unfortunately, too few physicians seem to be interested in this technique which, in my opinion, is absolutely central to the correct identification of a causative agent in pneumonia. Microscopic examination of gram-stained sputum makes it possible to identify bacteria that are responsible for infection of the lower respiratory tract. The result is largely dependent upon the quality ofthe specimen. An ideal sputum specimen contains an ample number of cells that come from below the larynx and is free of squamous epithelial cells that derive from the mouth. In bacterial pneumonia such a specimen contains profuse numbers of polymorphonuclear neutrophils (PMNs). When large
Correspondence: Dr. Daniel M. Musher, Infections Disease Section, Houston VAMC (15lB), 2002 Holcombe Boulevard, Houston, Texas 77030. Clinical Infectious Diseases 1992;15:1048-9 This article is in the public domain.
1. Musher OM. Infections caused by Streptococcus pneumoniae: clinical spectrum, pathogenesis, immunity, and treatment. Clin Infect Dis 1992;14:801-9. .. 2. Murray PR, Washington JA II. Microscopic and bacteriologic analysis of expectorated sputum. Mayo Clin Proc 1975;50:339-44.
numbers of bacteria are seen in a sputum sample that meets these criteria, they are highly likely to be the cause of the infection. The absence of bacteria in such a specimen is strong evidence of a nonbacterial process. In viral and mycoplasmal pneumonia, tracheal and bronchial epithelial cells are more likely to predominate in the sputum, and it can be difficult for the unskilled reader to be certain that the specimen is of good quality. The process of microscopic examination begins with scanning at a low power (X 100 magnification). Areas that contain large numbers ofPMNs and few buccal epithelial cells should then be examined at Xl ,000 magnification. The examiner should focus on areas that are free of buccal epithelial cells to avoid being confused by the large numbers of bacteria that may be adherent to them. These suggestions are entirely consistent with the suggestion that, under Xl 00 magnification, < 10 such cells be present per field. My statement that 15-20 PMNs should be present is more stringent than the suggested >25 PMNs per low-power field [1-3]. However, good sputum specimens usually have far more than this number, and my concept is that a high standard increases the likelihood of valid results. In bacterial pneumonia, sputum specimens are less appropriate to the degree that they
Downloaded from http://cid.oxfordjournals.org/ at Deakin University Library on August 10, 2015
Evaluation of Sputum Gram Stain
CID 1992; 15 (December)
Correspondence
Julie L. Steiner, Edward J. Septimus, and Carl V. Vartian Program in Infectious Diseases, Memorial Healthcare System, University of Texas Medical School, Houston, Texas
References 1. Bresee J, Edwards M. Psoas abscess in children. Pediatr Infect Dis J 1990;9:201-6. 2. Ricci M, Rose F, Meyer K. Pyogenic psoas abscess: worldwide variations in etiology. World J Surg 1986;10:834-43. 3. Leu SY, Leonard MB, Beart RW Jr, Dozois R. Psoas abscess: changing patterns ofdiagnosis and etiology. Dis Colon Rectum 1986;29:694-8.
SIR-The State-of-the-Art Clinical Article in the April issue of Clinical Infectious Diseases [1] has an ambiguous statement that the readership should note. Dr. Musher commented, ". . . sputum specimens must contain areas with at least 15-20 WBCs [white blood cells] and no epithelial cells in a standard microscopic field under Xl ,000 magnification. If sufficient numbers of inflammatory cells are not present, the specimen material is inappropriate." When a sputum gram stain is examined at Xl ,000 magnifica-
4. Kyle J. Psoas abscess in Crohn's disease. Gastroenterology 1971; 61:149-55. 5. Musher D. Infections caused by Streptococcus pneumoniae: clinical spectrum, pathogenesis, immunity, and treatment. Clin Infect Dis 1992; 14:80 1-9. 6. DiNubile M Jr, Albornoz MA, Stumacher RJ, et al. Pneumococcal softtissue infections: possible association with connective tissue diseases. J Infect Dis 1991;163:897-900. 7. Levine JF, Hiesiger EM, Whelan MA, et al. Pneumococcal meningitis associated with retroperitoneal abscess. A rare complication oflumbar puncture. JAMA 1982;248:2308-9. 8. Scott B, Schmidt J. Pneumococcal meningitis due to psoas abscess. South Med J 1989;82: 1310-1.
tion, an unreliable specimen could be misinterpreted if no epithelial cells are seen. On the other hand, a reliable specimen may be labeled unreliable if an epithelial cell is seen. Current standards for sputum evaluation [2] require that gram-stained slides be first examined at low-power field (X 100); specimens are considered reliable if < I0 epithelial cells and>25 WBCs are present. The examiner may then switch to X1,000 magnification for further study of the slide and presumptive identification of pathogens. Sary O. Beidas William A. Davis Clinic, St. Paul, Virginia
References Correspondence: Dr. Sary O. Beidas, ARH Wm. Davis Clinic, 63 North Drawer T, St. Paul, Virginia 24283. Clinical Infectious Diseases 1992;15:1048 © 1992 by The University of Chicago. All rights reserved. 1058-4838/92/1506-0020$02.00
Reply SIR-I thank Dr. Beidas for his comments on the sputum gram stain. Unfortunately, too few physicians seem to be interested in this technique which, in my opinion, is absolutely central to the correct identification of a causative agent in pneumonia. Microscopic examination of gram-stained sputum makes it possible to identify bacteria that are responsible for infection of the lower respiratory tract. The result is largely dependent upon the quality ofthe specimen. An ideal sputum specimen contains an ample number of cells that come from below the larynx and is free of squamous epithelial cells that derive from the mouth. In bacterial pneumonia such a specimen contains profuse numbers of polymorphonuclear neutrophils (PMNs). When large
Correspondence: Dr. Daniel M. Musher, Infections Disease Section, Houston VAMC (15lB), 2002 Holcombe Boulevard, Houston, Texas 77030. Clinical Infectious Diseases 1992;15:1048-9 This article is in the public domain.
1. Musher OM. Infections caused by Streptococcus pneumoniae: clinical spectrum, pathogenesis, immunity, and treatment. Clin Infect Dis 1992;14:801-9. .. 2. Murray PR, Washington JA II. Microscopic and bacteriologic analysis of expectorated sputum. Mayo Clin Proc 1975;50:339-44.
numbers of bacteria are seen in a sputum sample that meets these criteria, they are highly likely to be the cause of the infection. The absence of bacteria in such a specimen is strong evidence of a nonbacterial process. In viral and mycoplasmal pneumonia, tracheal and bronchial epithelial cells are more likely to predominate in the sputum, and it can be difficult for the unskilled reader to be certain that the specimen is of good quality. The process of microscopic examination begins with scanning at a low power (X 100 magnification). Areas that contain large numbers ofPMNs and few buccal epithelial cells should then be examined at Xl ,000 magnification. The examiner should focus on areas that are free of buccal epithelial cells to avoid being confused by the large numbers of bacteria that may be adherent to them. These suggestions are entirely consistent with the suggestion that, under Xl 00 magnification, < 10 such cells be present per field. My statement that 15-20 PMNs should be present is more stringent than the suggested >25 PMNs per low-power field [1-3]. However, good sputum specimens usually have far more than this number, and my concept is that a high standard increases the likelihood of valid results. In bacterial pneumonia, sputum specimens are less appropriate to the degree that they
Downloaded from http://cid.oxfordjournals.org/ at Deakin University Library on August 10, 2015
Evaluation of Sputum Gram Stain
CID 1992; 15 (December)
