Lilian Sool-Esol MicrobeWiki Prof. Angela Hahn 16 December, 2013
In 1961, Frenkel and Hirsch were the first to describe the Granulicatella bacteria genus as a nutritionally variant streptococcus (NVS) (Christensen et al., 2001). The Granulicatella genus is known to be a normal flora of the upper respiratory, gastrointestinal and urogenital tracts of humans. Normal flora is a microorganism that normally resides at a given site and under normal circumstances does not cause disease. Granulicatella adiacens whose genus name was formerly known as Abiotrophia because the bacteria genus is believed to be nutritionally deficient and even when samples are strained in the laboratory, a supplemented media with rich agar is used to culture samples of these bacteria. The word “Abiotrophia” means life nutrition deficiency (Bizzarro et al., 2011). Granulicatella adiacens, a species of this genus is found in the oral cavity, intestine and genitourinary tract of humans (Vandana et al., 2010). Infections in these areas lead to endovascular, central nervous system, ocular, oral bone and joint and urogenital tracts infections. It is also associated with diseases like endocarditis, bacteremia and septic arthritis (Bizzarro et al., 2011). The G. adiacens has a normal commensal relationship with most the human mucosal surfaces which allows it to affect those areas of the human body and although it has the possibilities of infecting all these areas, it rarely causes diseases (Gardenier et al., 2011).
G. adiacens bacteria are gram positive with streptococcus morphology. Sometimes it appears as cocci, coccobacilli or rod shaped cells. The cellular morphology depends on growth conditions. Their sizes range from 0.4 to 0.6 microns. G+C content of G. adiacens bacteria DNA is around 36.6 – 37.4 mol%. This bacteria is also known to be monophyletic. It is a facultative anaerobe which can survive in both aerobic and anaerobic environments with a temperature of about thirty seven (37) degrees Celsius (Collins MD et al., 2000). A Granulicatella genus bacterium is a fastidious microorganism; meaning, it has a complex nutritional requirement and can only grow in a specific diet of nutrients. Most fastidious microorganisms require blood or hemoglobin, amino acids and some vitamins to grow. These types of microorganisms are known to cause infections in humans and other organisms that have blood or hemoglobin. This makes its identification difficult because a unique culture media is required for the growth of isolates of G. adiacens. The type of media used to culture these fastidious bacteria in the laboratory is known as BD Chocolate Agar. The chocolate agar is supplemented with hemoglobin (blood) and yeast concentrate. There are two common types of chocolate agars used; the BD Chocolate Agar (GC II Agar with IsoVitalex) and the BD Chocolate Agar (Blood Agar No. 2 Base). The GC II Agar with IsoVitalex base nutrients contains blood; casein; selected meat peptones as a source of nitrogen; phosphates, which helps to regulate pH; and corn starch which helps to neutralize toxic fatty acids that may be present in the agar. The Blood Agar base is sometimes used as a substitute. The Blood base agar contains blood, liver digest, Proteose peptone and yeast extract which serves as a source of nitrogen and other vitamins for the growth of the microbe that needs to be cultured. However, Granulicatella adiacens is plated on the BD Chocolate Agar (GC II Agar with IsoVitalex) to reveal growth of nutritionally variant streptococci. Most laboratories use either horse or sheep blood as a source of hemoglobin. A way of identifying these bacteria is that when plated on a BD Chocolate Agar (Blood Agar No. 2 Base), it shows a very slow growth compare to BD Chocolate Agar (GC II Agar with IsoVitalex) (Perkins et al., 2003 & “Instructions for Use – Ready-To-Use Plated Media." 2011).
Scientists find this bacteria genus difficult to identify because it also appears as a gram negative bacteria sometimes and it has a range of form of shapes in which it appears which makes it uneasy to diagnose patience suffering with infections or diseases from this microbe. On normal circumstance, clinical diseases caused by G. adiacens are identified based on their phenotypic character by 16S rRNA gene sequencing. (Collins MD et al., 2000).
Taxonomy: Bacteria, Firmicutes, Bacilli, Lacotabacillales, Carnobacteriaceae, Granulicatella, Granulicatella adiacens. BIOS: Taxonomy (http://www.gbif.org/species/119570537)
Below are links to pictures of G. adiacens culture growth of isolated colonies after two days of streaking each plate. We notice that there is a slower growth on the Blood base Agar. (Please Click on the links to view pictures)
Sample of G. adiacens growth in BD Chocolate Agar (GC II Agar with IsoVitalex) (http://hampc168.blog.163.com/blog/static/1697976200701910515808/)
BD Chocolate Agar (Blood Agar No. 2 Base) showing slow rate of G. adiacens growth (http://hampc168.blog.163.com/blog/static/1697976200701910515808/)
A case of an infected endocarditis (http://upload.wikimedia.org/wikipedia/commons/7/73/Haemophilus_parainfluenzae_Endocarditis_PHIL_851_lores.jpg)
Christensen JJ, Facklam RR. 2001. Granulicatella and Abiotrophia species from Human Clinical Specimens. J. Clin. Microbiol. 39(10): 3520-3523 http://jcm.asm.org/content/39/10/3520.full
Bizzarro MJ, Callan DA, Farrel PA, Dembry L-M, Gallagher PG. 2011. Granulicatella Adiacens and Early-Onset Sepsis in Neonate. Emrg Infect Dis 17(10): 1971-1973 http://jmm.sgmjournals.org/content/61/Pt_6/755.full
Vandana KE, Mukhopadhyay C, Rau NR, Ajith V, Rajath P. 2010. Native Valve Endocarditis and Femoral Emolism due to Granulicatella Adiacens: A Rare Case Report. Braz J Infect Dis 14(6) http://dx.doi.org/10.1590/S1413-86702010000600015
Perkins A, Osorio S, Serrano O, Del Ray MC, Sarria C, Domingo D, Lopez-Brea M. 2003. A Case of Endocarditis due to Granulicatella adiacens. Clinical Microbiology and Infection 9(6): 576-577 http://onlinelibrary.wiley.com/doi/10.1046/j.1469-0691.2003.00646.x/full
Gardenier JC , Hranjec T, Sawyer RG, Bonatti H. 2011. Granulicatella Adiacens Bacteremia in an Elderly Trauma Patient. Surg Infect (Larchmt) 12(3): 251-3 http://www.ncbi.nlm.nih.gov/pubmed/21524203
Collins MD, Lawson PA. 2000. The Genus Abiotrophia (Kawamura et al.) is not Monophyletic: Proposal of Granulicatella gen. nov., Granulicatella adiacens comb. nov., Granulicatella Elegans comb. nov. and Granulicatella Balaenopterae comb. nov. International Journal of Systematic and Evolutionary Microbiology. 50:365-369 http://ijs.sgmjournals.org/content/50/1/365.full.pdf
Collins MD, Lawson PA. 2000: Granulicatella adiacens (Bouvet et al., 1989) BIOS:Baceteriology Insight Orienting System in the Catalogue of Life in The Catalogue of Life Partnership: Catalogue of Life. http://www.gbif.org/species/119570537
“Instructions for Use – Ready-To-Use Plated Media." Bd.com. Becton Dickinson, Sept. 2011. Web. 12 Dec. 2013. http://www.bd.com/resource.aspx?IDX=8994