Acinetobacter baumannii: The Emergence of a Dangerous Multidrug-Resistant Pathogen

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By: Kerri-Lynn Conrad

Figure 1. A colored SEM depiction of Acinetobacter baumannii, an emerging multidrug-resistant pathogen that causes opportunistic infections associated with high mortality rates.

Introduction

Figure 3. SEM depiction of a cluster of gram-negative, non-motile, rod bacteria Acinetobacter baumannii.

Genome Structure

Figure 2. The genome of Acinetobacter baumannii consists of 3,976,746 base pairs. Several pathogenicity islands were identified in the genome through sequence homology comparisons.

Cell Structure

Figure 3. Acinetobacter baumannii membrane transporter PilQ allows initial entry of foreign DNA into the cell. Foreign DNA is then bound by protein ComE and is directed to cytoplasmic membrane transporter ComA.

Epidemiology

Figure 4. Several regions around the world are attempting to deal with outbreaks of Acinetobacter baumannii infection. Although Acinetobacter baumannii has been a problem in hospitals for many years, the pathogen started to receive attention after the rise in infections among soldiers serving in Iraq and Afghanistan.

Pathology

Figure 5. Acinetobacter baumannii can be found in the natural microbial flora of the human skin. However, some pathogenic strains can infect the human respiratory tract, open wounds, or the bloodstream. Acinetobacter baumannii's resistance to many antibiotics and diverse metabolism allows it to subsist in various environments.

Multidrug-Resistance

Figure 6. In a study conducted in four community hospitals on Acinetobacter baumannii infections in patients over the age of 60, the pathogen gained resistance to all 8 antibiotic classes tested in only five years.

Implications for Hospitals

Figure 7. Acinetobacter baumannii infections among immune compromised patients is a major problem in hospitals. Susceptible patients often obtain the infection from hospital equipment, staff members, or other patients.

Implications for Hospitals

Figure 8. An American soldier at a military field hospital battling Acinetobacter baumannii that infected an open wound.

References

1 Dominguez, G., Dambaugh, T. R., Stamey, F. R., Dewhurst, S., Inoue, N. & Pellett, P. E. 1999. Human herpesvirus 6B genome sequence: coding content and comparison with human herpesvirus 6A. J Virol 73:8040–8052.

2 Gompels, U. A., Nicholas, J., Lawrence, G., Jones, M., Thomson, B. J., Martin, M. E., Efstathiou, S., Craxton, M. & Macaulay, H. A. 1995. The DNA sequence of human herpesvirus-6: structure, coding content, and genome evolution. Virology 209:29–51.

3 Braun, D. K., Pellett, P. E., Hanson C. A. 1995. Presence and expression of human herpesvirus 6 in peripheral blood mononuclear cells of S100-positive, T cell chronic lymphoproliferative disease. J. Infect. Dis. 171:1351–1355.

4 Meyne, J., Ratliff, R. L., Moyzis, R. K. 1989. Conservation of the human telomere sequence (TTAGGG)n among vertebrates. Proc. Natl. Acad. Sci.USA 86:7049–7053.

5 Clark, D. A. 2000. Human herpesvirus 6. Rev Med Virol 10:155–173

6 Mendez J.C., Dockrell, D.H., Espy, M.J., Smith, T.F., Wilson, J.A., Harmsen, W.S., Ilstrup, D., Paya, C.V. 2001. Human beta-herpesvirus interactions in solid organ transplant recipients. J Infect Dis 183(2):179-184.

7 Nicholas, J., Martin M.E. 1994. Nucleotide sequence analysis of a 38.5-kilobase-pair region of the genome of human herpesvirus 6 encoding human cytomegalovirus immediate-early gene homologs and transactivating functions. J. Virol. 68:597–610

8 Dockrell, D. H. 2003. Human herpesvirus 6: molecular biology and clinical features. J. Med. Microbiol. 52:5–18.

9 Zou, P., Isegawa, Y., Nakano, K., Haque, M., Horiguchi, Y., Yamanishi, K. 1999. Human herpesvirus 6 open reading frame U83 encodes a functional chemokine. J Virol 73:5926–5933.

10 Rotola, A., Ravaioli, T., Gonelli, A., Dewhurst, S., Cassai, E. & DiLuca, D. 1998. U94 of human herpesvirus 6 is expressed in latently infected peripheral blood mononuclear cells and blocks viral gene expression in transformed lymphocytes in culture. Proc Natl Acad Sci USA 95:13911–13916.

11 Chou, S., Marousek G. I. 1994. Analysis of interstrain variation in a putative immediate-early region of human herpesvirus 6 DNA and definition of variant-specific sequences. Virology 198:370–376.

12 Bolle, L.D., Naesens L., Erik, D.C. 2005. Update on human herpesvirus 6 biology, clinical features, and therapy, Clin Microbiol Rev 18:217–245.

13 Brown, N. A., Sumaya, C. V., Liu, C.-R., Ench, Y., Kovacs, A., Coronesi, M., Kaplan, M. H. 1988. Fall in human herpesvirus 6 seropositivity with age. Lancet ii, 396.

14 Ranger S., Patillaud S., Denis F., Himmich A., Sangare A., M'Boup S. 1991.Seroepidemiology of human herpesvirus-6 in pregnant women from different parts of the world. J Med Virol 34:194-8.

15 Enders, G., Biber, M., Meyer, G., Helftenbein, E. 1990. Prevalence of antibodies to human herpesvirus 6 in different age groups, in children with exanthema subitum, other acute exanthematous childhood diseases, Kawasaki syndrome, and acute infections with other herpesviruses and HIV. Infection 18:12–15.

16 Wang, F. Z., Dahl, H., Ljungman, P., Linde, A. 1999. Lymphoproliferative responses to human herpesvirus-6 variant A and variant B in healthy adults. J. Med. Virol. 57:134–139.

17 Collot, S., Petit, B., Bordessoule, D., Alain, S., Touati, M., Denis, F., Ranger-Rogez, S. 2002. Real-time PCR for quantification of human herpesvirus 6 DNA from lymph nodes and saliva. J. Clin. Microbiol. 40:2445–2451.

18 van Loon, N. M., Gummuluru, S., Sherwood, D. J., Marentes, R., Hall, C. B. & Dewhurst, S. 1995. Direct sequence analysis of human herpesvirus 6 (HHV-6) sequences from infants and comparison of HHV-6 sequences from mother/infant pairs. Clin Infect Dis 21:1017–1019.

19 Portolani M., Cermelli C., Moroni A. 1993. Human herpesvirus-6 infections in infants admitted to hospital. J. Med.Virol. 39:146–51

20 Pruksananonda, P., Hall, C.B., Insel, R.A., McIntyre, K., Pellett, P.E., Long, C. E., Schnabel, K. C., Pincus, P. H., Stamey, F. R., Dambaugh, T. R. 1992. Primary human herpesvirus 6 infection in young children. N. Engl. J. Med. 326:1445–1450.

21 Stoeckle M.Y. The spectrum of human herpesvirus 6 infection: from roseola infantum to adult disease. Annu Rev Med 2000: 51: 423–430.

22 Di Luca, D., Mirandola, P., Ravaioli, T., Bigoni, B., Cassai, E. Distribution of HHV-6 variants in human tissues. Infectious Agents and Disease 1996;5:203-14.

23 Luppi, M., Barozzi, P., Morris, C.M., Merelli, E., Torelli, G. 1998. Integration of human herpesvirus 6 genome in human chromosomes. Lancet 352:1707-8.

24 Lusso, P., Gallo, R.C. 1995. Human herpesvirus 6 in AIDS. Immunol Today 16:67-71.

25 Nacheva, E.P., Ward, K.N., Brazma, D., Virgili, A., Howard, J., Leong, H.N., Clark, D.A. 2008. Human herpesvirus 6 integrates within telomeric regions as evidenced by five different chromosomal sites. Journal of Medical Virology, 80:1952–1958.

26 Hall, C.B., Caserta, M.T., Schnabel, K., Shelley, L.M., Marino, A.S., Carnahan, J.A. 2008. Chromosomal integration of human herpesvirus 6 is the major mode of congenital human herpesvirus 6 infection. Pediatrics 122(3): 513–520.

27 Ward, K.N., Leong, H.N., Nacheva, E.P., Howard, J., Atkinson, C.E., Davies, N.W., Griffiths, P.D., Clark, D.A. 2006. Human herpesvirus 6 chromosomal integration in immunocompetent patients results in high levels of viral DNA in blood, sera, and hair follicles. J Clin Microbiol 44:1571–1574.

28 Gompels, U. A., Macaulay, H.A. 1995. Characterization of human telomeric repeat sequences from human herpesvirus 6 and relationship to replication. J. Gen. Virol. 76:451-458.

29 Arbuckle, J.H., Medveczky, M.M., Luka, J., Hadley, S.H., Luegmayr, A., Ablashi, D., Lund, T.C., Tolar, J., DeMeirleir, K., Montoya, J.G., Komaroff, A.L., Ambros, P.F., Medveczky, P.G. 2010. The latent human herpesvirus-6A genome specifically integrates in telomeres of human chromosomes in vivo and in vitro. Proc Natl Acad Sci USA. 107:5563–5568.

30 Daibata, M., Taguchi, T., Taguchi, H., Miyoshi, I. 1998.Integration of human herpesvirus 6 in a Burkitt's lymphoma cell line. Br J Haematol 102:1307-1313

31 Kishi, M., Harada, H., Takahashi, M., Tanada, A., Hayashi, M., Nonoyama, M., Josephs, S.F., Buchbinder, A., Schachter, F., Ablashi, D., Wong-Staal, F., Salahuddin, S.Z., Gallo, R.C. 1988. A repeat sequence, GGGTTA, is shared by DNA of human herpesvirus 6 and Marek’s disease virus. J. Virol. 62:4824–4827.

32 Tanaka-Taya, K., Sashihara, J., Kurahashi, H., Amo, K., Miyagawa, H., Kondo, K., Okada, S., Yamanishi, K. 2004. Human herpesvirus 6 (HHV-6) is transmitted from parent to child in an integrated form and characterization of cases with chromosomally integrated HHV-6 DNA. J Med Virol 73:465-473.

33 Daibata, M., Taguchi, T., Nemoto, Y., Taguchi, H., Miyoshi, I. Inheritance of chromosomally integrated human herpesvirus 6 DNA. Blood 1999; 94:1545-1549.

34 Ablashi, D.V., Eastman, H.B., Owen, C.B., Roman, M.M., Friedman, J., Zabriskie, J.B., Peterson, D.L., Pearson, G.R., Whitman, J.E. 2003. Cross-reactivity with myelin basic protein and human herpesvirus-6 in multiple sclerosis. Annu Neurol. 53(2): 189–197.

Edited by Kerri-Lynn Conrad, student of Joan Slonczewski for BIOL 238 Microbiology, 2011, Kenyon College.