International Journal of Scientific & Engineering Research, Volume 5, Issue 12, December-2014 88

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Cancer infection and its relationship with

Streptococcus mitis increasing numbers in human mouth

Abrar N. Mohammad Zaki1 , Alaa D. Kadum 2, Nibal Kh. Mousa1 , Azher S. Abdel Kareem1 , Baydaa H. Obaid1

Abstract— The study aimed to determine the relationship between the changes happened in numbers and kinds of bacteria in mouth of human and the cancer infection such as oral and digestion cancer consider the increasing and changes in bacteria kinds as early indicator to develop cancer in body. Saliva samples which not Stimulation, were collected from various places in Baghdad city from who not suffer from cancer infection but exposed to chemical or radiation components as first groups and the second groups consist of people exposed to chemical or radiation components. Samples collection from them after make sure they don’t take food, no smoking or used toothpaste rinsing mouth at least for one hour before. Saliva were cultured on Mitis Salivarius agar cultured by spreading dilution on agar, incubated anaerobically for 48 hours .After bacteria calculated and diagnosed species by using biochemical fermentation of sugars and examination of catalase , in addition api 20 strep to examine the bacteria Streptococcus spp and showed results, the first group showed the highest percentage of type Streptococcus mitis at 13 persons and attributed the reason for being for a long time for the chemicals or radioactive materials as a result of the nature of their work or location of their home , the second group appeared to have the highest proportion of two types Streptococcus mutans or Streptococcus salivarius, that reflect increasing Streptococcus mitis in mouth saliva of human the first marker to cancerous disease.

Index Terms— Cancer, Saliva, S.salivarius, S.mitis, S.mutans, Streptococci, oral bacteria.


—————————— ——————————
ancer is one of death causing in every day that reflected from the ratio of person whom death from using tobacco
and alcohol were 43%. In every years 10 million of new cases in a world and 6 million were died by cancer diseases “[1]”. Some studies showed that the oral bacteria were increased in oral, pharyngeal and lymph node cancers “[2,3]” specially oral streptococci”[4,5]” and some anaerobic bacteria such as Prevotella sp. , Veillonella sp., Porphy- romonas sp. and Capnocytophaga sp. which were elevated too “[3,6,7]”.
Cancer happened depending on presence of sugar ponds in cell membrane “[8]” which work as receptor to bacteria in limited types, the bacterial colonies changes in cancer cell bind to change cell surface receptor “[8,9]”.
Persons who were infected with oral epithelial cell cancer showed
increasing in numbers of Streptococcus mitis , Prevotella melaninogenica
and Capnocytophaga gingivalis incomparison with healthy peoples
“[10]” ,other causes of oral cancer were viral infection “[11]” , weak
oral health and infected via Candida yeast types “[12]”.
Some of germs relationship with type of cancer such as Chlamydia trachomatis related to cervical cancer”[13]” , Streptococcus bovis is con- tact with colon cancer “[14]” and Helicobacter pylori related to gastric glands “[15,16]”.


1-Abrar N.Mohammad Zaki , Nibal Kh. Mousa , Azher S. Abdel Kareem , Baydaa H. Obaid. Minstry of science and technology .Iraq

2- Alaa D. Kadum. Baghdad university .Iraq

Different types of bacteria had several mechanism for playing role in development cancer, dependent on interaction and initiated severe inflammation with direct or indirect way “[17]” or from metabolism way for example; oral microflora in human induce cancer by convert alcohol to carcinogenic acetaldehyde by digest alcohol which leads to produce levels of acetaldehyde that induce DNA damage and in- creased epithelial cell division leading to cancer “[18,19]”.Their pres- ence Streptococcus anginosus DNA inside oral pharyngeal tumor cell “[5,20]”.
Bacteria types of Treponema denticola , Streptococcus mitis and

S.anginosus play a role in esophagus cancer due to induction inflam-

matory cytokines leading to increase the appearing cancer and when
decreased number of these bacteria decreased from infection risk “[21]”.Bacteria has ability to convert alcohol to acetaldehyde via pro- duced enzymes ; alcohol dehydrogenase (ADH) and cytochrome p450 oxidase (CYP) ,in addition, bacteria produce other very toxic material that played important role in causing cancer and in metabolism pro- cess ; acetaldehyde convert to acetate by acetaldehyde dehydrogenase (ALDH)”[22]”
Oral viridians Streptococci have ability to produce acetaldehyde invitro when incubated with alcohol where S.salivarius , S.mitis and S.intermedius produced large amount of acetaldehyde thus led to can- cer “[23]” ,also Narikiyo et al.,2004 pointed S.mitis compose 43% in healthy persons and the increased about this considers indicator to cancer presence.
The study aimed to indicate Cancer as early as much by using natural flora as detector and early detector for persons whom had infected ability with cancer, so that we can avoid them from infection and help them with early treatment before focus cancer.

2 Materials and methods

2.1 Sample collection ــــ Saliva samples collection were 52 from dif- ferent places in Baghdad City divided into 26 sample from people

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whom were working in atomic energy institutions and 26 sample from other institutions and making sure not eating or smoking also didn’t use toothpaste or rinses for at least one hour before collection samples, then kept them in sterile tubes and mixed by vortex to homogeneity of distribution bacteria in it.

2.2 Isolation and diagnosis bacteria ــــSerious dilution on saliva samples worked according to”[24]” and diagnosed bacteria morpholo- gy as “[25]”.

2.3 Carbohydrate test and diagnosis with api ـــUsed the carbo- hydrate fermentation as “[24]”.

2.4 Numbering bacteriaـــCalculated bacterial colony depended on


3 Statistical analysis : The results analyzed by used t-test of S.mitis ratio of doubtful about them and the results show significant differences under p<0.05, this results confirms that the whenever high- er the percentage of bacteria more than 50% whenever the result (table
3) was more significant “[26]”.

4 Results

The colony of Streptococci appear different shape because different types on mitis salivarius agar (Fig 1). After work a slide from bacteria and staining with gram stain Streptococcus cells appear positive cocci form strep under microscope (Fig 2) .The Negative to catalase test
,diagnosis of Streptococci by sugars fermentation and api 20 Strep ap- pears 5 types of Streptococcus which is S.mutans , S.sobrenus , S.salivarius
, S.oralis , S.mitis and S.mitor (Fig 3, 4) (Table 1).
After diagnosis bacteria ; calculated more appear type in every person mouth ratio to other types , in 13 person from 52 the more ap- pear type is S.mitis and in the other person the more appear type is neither S.salivarius or S.mutans , the mean of percentage is 72.4% to 13 person , the minimum percentage is 55% and the maximum is over than 95% and the more repeating in the percentage 70% and 80% to 13 person ,the other person, the mean is 13% the minimum percentage is zero and the maximum is 40% the more repeating in the percentage less than 10%.
The total number of genus Streptococcus is 0.3 * 106-289 *106 cell / ml at exposed persons to chemical or radioactive materials and 1* 106- 550 *

106 cell/ ml at non-exposed persons (Table 2).

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5 Discussions

Early detection followed by appropriate treatment, can increase cure rates to 80 or 90%, and greatly improve the quality of life by minimizing extensive, debilitating treatments”[27]”. Despite the accessibility of the oral cavity to direct examination, these malig- nancies are often not detected until a late stage “[28,29]”. Oral can- cer is unusual in that it carries a high risk of second primary tu- mors. Patients who survive a first cancer of the oral cavity have up to a 20-fold increased risk of developing a second primary oral can- cer and that risk lasts 5–10 years and sometimes longer major risk factors for oral .
The reason for these shifts in bacterial colonization of cancer lesions
is unclear. Mechanistic studies of bacterial attachment provide
some insights, however. Research has repeatedly shown that oral bacteria demonstrate specific tropisms toward different biological surfaces in the oral cavity such as the teeth, mucosa, and other bac- teria “[29,30]”. The non-shedding surfaces of the teeth offer a far different habitat than the continually shedding surfaces of the oral mucosa. Due to the repeated shedding of epithelial cells, there is less time for a complex biofilm to develop on soft tissue surfaces; thus, a premium is placed on potent mechanisms of adhesion. The differences in bacterial tropisms for specific oral sites suggest that different intra-oral surfaces and bacterial species have different re- ceptors and adhesion molecules that dictate the colonization of dif- ferent oral surfaces.
It is now recognized that bacteria bind to and colonize mucosal
surfaces in a highly selective manner via a "lockand key" mecha- nism. Adhesins on bacteria bind specifically to complementary re- ceptors on the mucosal surfaces of the host. These adhesins differ from species to species leading to specificity in attachment to dif- ferent surfaces. Studies have shown that even within genera, colo- nization patterns of individual species may differ markedly “[29,31]”. Streptococcus salivarius, for example, preferentially colo- nized the oral soft tissues and saliva compared to the teeth, while the reverse was true of Streptococcus sanguis.
Each of”[10,21]” pointed S.mitis increased more than other
Streptococci in oral infected with oral cancer and esophagus cancer
. the 13 person which are increased S.mitis ; 8 persons of them
worked at atomic energy and 4 of them work in chemical materials
for a long time and the last one he live near oil filtration site
.Narikiyo and other in 2004 pointed S.mitis compose 43% in healthy
persons and when increased over that considers indicator to cancer

6 Conclusions

The results reflected; increased the number of S.mitis at exposed persons to chemicals or radioactive materials to a long time and the percentage over 50 % that persons have readiness to infecte with can- cer diseases.

7 Acknowledgments

The authors wish to thank all persons for their help to perform this research especially in the ministry of science and technology


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