**2.** *Salmonella*

Efforts related with classification of these bacteria since first *Salmonellas* has been found also continues recently. When *Salmonella* bacteria are examined by DNA/DNA hybridization trials which are performed among bacteria, all *Salmonellas* should be accepted as one species including Arizona species added to them. According to this, subgenuses that Kauffman has created among *Salmonellas* according to genetic and other characteristics (subgenus 1, subgenus 2, subgenus 3= Arizona and subgenus 4) and subgenus 5 which was added by Le Minor should be accepted as sub-species instead of subgenus.

Up to the present, *Salmonella* bacteria were named according to their pathology, their host and the city where they have been found first and an attention was paid to use an individual name for every bacteria within the same antigen structure in Kauffman-White classification. These bacteria which were accepted as individual serovars were classified as separate species. It is known that these characteristics of bacteria are not appropriate and sufficient to determine a species and none of the methods that has been used up to the present is scientific in terms of taxonomy. Furthermore, international enterobacteriaceae subcommittee which is the most reliable organization about this subject have not performed a scientific guidance about various *Salmonellas* erovars classification. While studies continue, this committee has suggested as follows:

To protect validity of Kauffman white classification without having a bias related with definition of this species; to keep names of bacteria in *Salmonellas* ubgenus 1 (like individual species names) by continuing a normal tradition in medicine, cliniz and microbiology up to the present; when new bacteria which comply to this subgenus is found, to classify them

Isolation and Identification of Salmonellas from Different Samples 125

*Salmonella* bacteria reproduce in many ordinary mediums. They are aerobe and facultative anaerobe. Their reproduction temperature limit is very wide even they reproduce at 37° C best. (20°C- 42°C). This is extremely important for reproduction of *Salmonellas* which cause food intoxication at room temperature. They like to produce at average pH of 7,2. They make homogenous turbidity in bouillon and similar liquid medium. They make round, slab sided, mostly tumescent colonies with a diameter of 2-3 mm, regular surface. In colonies of various *Salmonellas* , some differences may exist in terms of size, protuberance, surface and side. *Salmonella* typhi may also make gnome colonies which may reach to 0,2-0,3 mm diameter within the first 24 hours. Biochemical characteristics of bacteria which are obtained from these colonies are same as normal colonies; and they are agglutinated with O serums only antigenically and they differ from bacteria in S colonies in terms of not reacting with anti H, anti Vi serums. If they are reproduced in mediums including sulfurous compounds, sulfates and tiosulfates which may be assimilated, normal colonies occur from bacteria that

Some of *Salmonellas* , S. Schottemuelleri (s. paratyphi) in particular and some others form M colonies in appropriate mediums. It is detected that these bacteria have M antigens and agglutination is prevented by anti O and anti H serums. Furthermore, R colonies are formed

by *Salmonella* which reproduce in inappropriate mediums (*Figure 2*).

**2.2 Reproduction and biochemical characteristics** 

make gnome colonies.

Fig. 2. *Salmonella* colonies

individually; to keep names of bacteria which have been found up to the present in other subgenus similarly, but in case of finding new bacteria which comply to this genus, to classify them only by antigenic formulas.

The idea which has arisen lately is that all *Salmonellas* including Arizona are single species and to classify this species as *Salmonella* enterica. Discriminations related with antigenic, biochemical, host and geographical distribution which are seen among bacteria has been depended on differentiation of this single species. Six subgroups were detected as a result of researches performed by DNA hybridization methods.

These are; *Salmonella*: 1 subgroup including s. enterica subspecies; *Salmonella* : 2 subgroup including salamae subgroup; *Salmonella*: 3a and *Salmonella*: 3b subgroups including arizonae and diarizonae subspecies; *Salmonella*: 4 subgroup including hautenae; *Salmonella*: 5 subgroup including bongori subspecies and *Salmonella*: 6 subgroup including indica subspecies.

In practice, bacteria are named as serovar names and for example, to use only *Salmonellas*  erovar typhimurium, even *Salmonellas* erovar typhimurium name is preferred instead of long names such as *Salmonella* enterica subsp., Enterica serovar typhimurium.

#### **2.1 Appearance and stanng characterstcs**

*Salmonella* bacteria are asporogenic, capsule-free, motile via peritrichous cilium (*Salmonella*  gallinarium or *Salmonella* pulorum are immotile), rod-shaped bacteria with an approximate length of 2,0-5,0 µm, width of 0,7-1,5 µm. They are stained well with bacteriologic stains and they are gram-negative *(Figure 1).* Most of them have type 1 (mannose sensitive (ms), hemagglutinating); S. Gallinarium and some origins have type 2 fimbriae. S. paratyphi As do not have fimbriae.

Fig. 1. Microscopic View of *Salmonella* 
