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Traditional and molecular techniques for the study of emerging bacterial diseases: one laboratory's perspective.

Houpikian P, Raoult D - Emerging Infect. Dis. (2002)

Bottom Line: Identification of emerging bacterial pathogens generally results from a chain of events involving microscopy, serology, molecular tools, and culture.Because of the spectacular molecular techniques developed in the last decades, some authors think that these techniques will shortly supplant culture.Serology provided indirect evidence for causality.

View Article: PubMed Central - PubMed

Affiliation: Unité des Rickettsies, Faculté de Médecine de Marseille, France.

ABSTRACT
Identification of emerging bacterial pathogens generally results from a chain of events involving microscopy, serology, molecular tools, and culture. Because of the spectacular molecular techniques developed in the last decades, some authors think that these techniques will shortly supplant culture. The key steps that led to the discovery of emerging bacteria have been reviewed to determine the real contribution of each technique. Historically, microscopy has played a major role. Serology provided indirect evidence for causality. Isolation and culture were crucial, as all emerging bacteria have been grown on artificial media or cell lines or at least propagated in animals. With the use of broad-range polymerase chain reaction, some bacteria have been identified or detected in new clinical syndromes. Culture has irreplaceable advantages for studying emerging bacterial diseases, as it allows antigenic studies, antibiotic susceptibility testing, experimental models, and genetic studies to be carried out, and remains the ultimate goal of pathogen identification.

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Canine monocytes (DH82) cultivated in vitro and heavily infected with Ehrlichia chaffeensis, as viewed by light microscopy after Giemsa staining. Typical ehrlichial inclusions (morulae) are observed within the cytoplasm of the infected cells (Giemsa, original magnification X600).
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Figure 4: Canine monocytes (DH82) cultivated in vitro and heavily infected with Ehrlichia chaffeensis, as viewed by light microscopy after Giemsa staining. Typical ehrlichial inclusions (morulae) are observed within the cytoplasm of the infected cells (Giemsa, original magnification X600).

Mentions: Cell culture is easy to use and may be very sensitive. Isolation of T. whipplei was obtained from valve and duodenal biopsy specimens by using human embryonic lung fibroblasts (HEL) (2,36). Ehrlichia chaffeensis and R. japonica were grown from blood samples of patients on canine macrophage cells (Figure 4) and African green monkey cells, respectively (9,46). Cultivation of facultative intracellular bacteria also was facilitated by cell culture. L. pneumophila has been isolated by using HEL cells while inoculated BCYE and agar plates remained sterile (47). With a bovine endothelial cell line, B. quintana was isolated for the first time from cutaneous biopsy material of a bacillary angiomatosis patient (48). Such enhanced sensitivity is a major advantage for an infection with low levels of bacteremia or when limited biopsy material is available (49). Indirectly, HEL cells also provided the first evidence for the role of a toxic factor in pseudomembranous colitis, which could be neutralized by clostridial antiserum. This observation led to the discovery of Clostridium difficile as the responsible agent (50).


Traditional and molecular techniques for the study of emerging bacterial diseases: one laboratory's perspective.

Houpikian P, Raoult D - Emerging Infect. Dis. (2002)

Canine monocytes (DH82) cultivated in vitro and heavily infected with Ehrlichia chaffeensis, as viewed by light microscopy after Giemsa staining. Typical ehrlichial inclusions (morulae) are observed within the cytoplasm of the infected cells (Giemsa, original magnification X600).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3369584&req=5

Figure 4: Canine monocytes (DH82) cultivated in vitro and heavily infected with Ehrlichia chaffeensis, as viewed by light microscopy after Giemsa staining. Typical ehrlichial inclusions (morulae) are observed within the cytoplasm of the infected cells (Giemsa, original magnification X600).
Mentions: Cell culture is easy to use and may be very sensitive. Isolation of T. whipplei was obtained from valve and duodenal biopsy specimens by using human embryonic lung fibroblasts (HEL) (2,36). Ehrlichia chaffeensis and R. japonica were grown from blood samples of patients on canine macrophage cells (Figure 4) and African green monkey cells, respectively (9,46). Cultivation of facultative intracellular bacteria also was facilitated by cell culture. L. pneumophila has been isolated by using HEL cells while inoculated BCYE and agar plates remained sterile (47). With a bovine endothelial cell line, B. quintana was isolated for the first time from cutaneous biopsy material of a bacillary angiomatosis patient (48). Such enhanced sensitivity is a major advantage for an infection with low levels of bacteremia or when limited biopsy material is available (49). Indirectly, HEL cells also provided the first evidence for the role of a toxic factor in pseudomembranous colitis, which could be neutralized by clostridial antiserum. This observation led to the discovery of Clostridium difficile as the responsible agent (50).

Bottom Line: Identification of emerging bacterial pathogens generally results from a chain of events involving microscopy, serology, molecular tools, and culture.Because of the spectacular molecular techniques developed in the last decades, some authors think that these techniques will shortly supplant culture.Serology provided indirect evidence for causality.

View Article: PubMed Central - PubMed

Affiliation: Unité des Rickettsies, Faculté de Médecine de Marseille, France.

ABSTRACT
Identification of emerging bacterial pathogens generally results from a chain of events involving microscopy, serology, molecular tools, and culture. Because of the spectacular molecular techniques developed in the last decades, some authors think that these techniques will shortly supplant culture. The key steps that led to the discovery of emerging bacteria have been reviewed to determine the real contribution of each technique. Historically, microscopy has played a major role. Serology provided indirect evidence for causality. Isolation and culture were crucial, as all emerging bacteria have been grown on artificial media or cell lines or at least propagated in animals. With the use of broad-range polymerase chain reaction, some bacteria have been identified or detected in new clinical syndromes. Culture has irreplaceable advantages for studying emerging bacterial diseases, as it allows antigenic studies, antibiotic susceptibility testing, experimental models, and genetic studies to be carried out, and remains the ultimate goal of pathogen identification.

Show MeSH
Related in: MedlinePlus