**2.2 Reproduction and biochemical characteristics**

124 Salmonella – A Dangerous Foodborne Pathogen

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

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

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

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

*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

long names such as *Salmonella* enterica subsp., Enterica serovar typhimurium.

classify them only by antigenic formulas.

indica subspecies.

do not have fimbriae.

researches performed by DNA hybridization methods.

**2.1 Appearance and stanng characterstcs** 

Fig. 1. Microscopic View of *Salmonella* 

*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 make gnome colonies.

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*).

Fig. 2. *Salmonella* colonies

Isolation and Identification of Salmonellas from Different Samples 127

(-) Negative (+) Positive

Motility + Indole - H2S + Oxidase - Urease - Nitrate reduction + Citrate Utilization + MR + VP - Lysine decarboxilation + Ornithine decarboxilation + Phenylalanine deamination - Malonate Utilization - Lactose - Sucrose - Salicine - Inositol - Amygdalin - Gas Production from glucose + β-galaktosidase (ONPG Test) - Reproduction in KCN -

Table 1. Biochemical characteristics of *Salmonellas* 

**3. Important terms n takng examnaton sample** 

procedure and by being careful in the following subjects.

medication.

As delay in the diagnosis of acute infection is unhealthful in terms of delay in the treatment and it is also dangerous that other persons may be infected due to more contact. To obtain rapid and correct etiological diagnosis is possible to take the examination material appropriately, to send it to the laboratory rapidly and to examine them in the laboratory well. Inability to produce the active germ is due to faulty examination material taking in general. Examination material should be taken by persons who know the purpose of such

It should be especially noted that examination material should be taken before administration of any antibiotics or other chemotherapeutic medications. Pathogen bacteria may not exist in the purulence even 24 hours after antibiotic administration. If bacteria that chemotherapeutic substance inhibit can not be produced from the examination material during the administration, it may be produced several days after discontinuation of the

 *Salmonellas* are not effective on lactose. This characteristics is important in first differentiation from Escherichias. As these bacteria which are planted in a separator plaque medium (endo, EMB) including lactose and an appropriate reagent are not effective on lactose, they make colorless colonies; however those effective on lactose make dark red, black, greenish bright colonies (*Figure 3*).

Fig. 3. View of *Salmonella* and Lactose Positive Colonies

*Salmonellas* do not effect on sucrose, adonitole and salicin in usual other than lactose. They digest glucose, mannite and maltose by producing acid and gas except *Salmonella* typhi and S. gallinarum; and *Salmonella* typhi and gallinarum digest them by producind acid only. They produce H2S in general (except S. paratyphi A); they are indole negative, methyl red positive, Vogesproskauter negative and they reproduce in citrated mediums (Simmon), they do not digest urea. They could not be produced in KCN (potassium cyanide 0,5%) mediums. ONPG (orthonitro phenyl galactopyranoside) assay is negative. (They do not have beta galactosidase enzymes that may digest lactose). This assay is positive in Arizona. Biochemical characteristics of *Salmonellas* were shown in *Table 1*.

 *Salmonellas* are not effective on lactose. This characteristics is important in first differentiation from Escherichias. As these bacteria which are planted in a separator plaque medium (endo, EMB) including lactose and an appropriate reagent are not effective on lactose, they make colorless colonies; however those effective on lactose make dark red,

black, greenish bright colonies (*Figure 3*).

Fig. 3. View of *Salmonella* and Lactose Positive Colonies

Biochemical characteristics of *Salmonellas* were shown in *Table 1*.

*Salmonellas* do not effect on sucrose, adonitole and salicin in usual other than lactose. They digest glucose, mannite and maltose by producing acid and gas except *Salmonella* typhi and S. gallinarum; and *Salmonella* typhi and gallinarum digest them by producind acid only. They produce H2S in general (except S. paratyphi A); they are indole negative, methyl red positive, Vogesproskauter negative and they reproduce in citrated mediums (Simmon), they do not digest urea. They could not be produced in KCN (potassium cyanide 0,5%) mediums. ONPG (orthonitro phenyl galactopyranoside) assay is negative. (They do not have beta galactosidase enzymes that may digest lactose). This assay is positive in Arizona.


Table 1. Biochemical characteristics of *Salmonellas* 
