Tinción de Gram de tejido: alcances y limitaciones / Gram stain of tissue biopsy: scope and pitfalls

La identificación de microorganismos en tejido es esencial para reconocer un proceso infeccioso. Inicialmente, mediante la coloración de hematoxilina-eosina, se puede identificar el patrón de inflamación asociado y luego, a través de tinciones basadas en plata y la tinción de Gramde tejido se visualizan los microorganismos. La tinción de Gram no solo sirve para bacterias, sino también para algunos hongos y parásitos; no obstante, esta técnica tiene algunos inconvenientes, como la contaminación con otros microorganismos y la imposibilidad de visualizar algunas bacterias, entre ellas Legionella pneumophila, Leptospira spp y Bartonella spp. En este artículode revisión se describirán los fundamentos del Gram de tejido, su contribución en el diagnóstico de infecciones como herramienta adicional para el reconocimiento de microorganismos, y sus limitaciones.

The identification of microorganisms in tissue is pivotal to recognize infectious processes.At first, the hematoxylin-eosin stain is used to identify the pattern of inflammation associated; after that, microorganisms are seen through Gram or silver stains. Gram Stain of tissue biopsy not only stains bacteria, but also a number of fungus and parasites. However, this technique has some disadvantages, such as contamination with other microorganisms, and lack of stain of some bacteria, including Legionella pneumophila, Leptospira spp and Bartonella spp. This review articleaims to describe the fundamentals of Gram stain of tissue biopsy and its assistance in infectious diagnosis as an additional tool for recognition of microorganisms, as well as its limitations.

Clinical and Histopathological Study of Cellulitis / 대한피부과학회지

BACKGROUND: Cellulitis is a suppurative inflammation involving particularly the subcutaneous tissue. There has been no data about its clinicopathologic features in Korea. OBJECTIVES: The purpose of this study was to investigate the clinicopathologic characteristics of cellulitis and to assess the yield rate of special stainings (Brown-Brenn, Gram) for organisms. METHODS: We reviewed the medical records and histologic sections of 45 patients who had been diagnosed as cellulitis in the Department of Dermatology, Chungbuk National University Hospital from January 1992 to August 1998. RESULTS: The results were as follows. 1. The sex ratio of male to female was 1.5:1 and average age was 43 years old. 2. The lower extremity was the most frequently involved site of cellulitis with a frequency of 53.4%. 3. Erythema, tenderness, local heating, swelling, and pain were almost always presenting clinical manifestations. 4. Diabetes mellitus was the most frequent underlying systemic disease. 5. The route of infection was suspected in 25 cases(55.6%). Tinea pedis was strongly suspected in 7 cases(28.0%), and followed by insect bite in 5 cases(20.0%), herpes zoster in 4 cases(16.0%), and trauma in 2 cases(8.0%). 6. The main complications were orthopedic problems including bursitis, osteomyelitis, and septic arthritis. 7. Microorganisms were isolated in 20 of 43 tissue cultures(46.5%). 8. It is important to suspect Escherichia coli as a causative organism if blistering cellulitis occurs, especially in patients with underlying systemic disease. 9. The most frequent histopathologic findings were perivascular lymphohistiocytic infiltrations in both dermis and subcutaneous fat simultaneously without vasculitis. 10. Special stainings(Brown-Brenn or Gram) were worthy to try, especially in the neutrophilic dominant cellulitis. 11. First-generation cephalosporin was chosen as primary antibiotics in 31 cases, and there was no difference in clinical course between its monotherapy and combined therapy. 12. Twenty percent of cases experienced recurrences. Lower extremity was most common site of recurrence(63.6%). CONCLUSION: Diabetes mellitus and tinea pedis were so closely bound up with cellulitis that control of those diseases is important in view of the clinical course of cellulitis. Special stainings(Brown-Brenn or Gram) were worthy to try, especially in the neutrophilic dominant cellulitis.