Solutions of different concentrations, of Ampicillin trihydrate (AT) and of a formulation of AT in Aluminium Magnesium Silicate (AMS), were used for sensitivity test on Salmonella gallinarum cultures. Also, S. gallinarum-infected chicks were treated with; 10 mg / Kg (AT), 10 mg / Kg (AT in AMS), 7.5 mg / Kg ( AT), 7.5 mg /Kg (AT in AMS). Mean inhibition area, 28.39 mm produced by AT did not vary significantly (P ) from 26.36 mm produced by AT in AMS. However, 17.5 105 Salmonella gallinarum culture forming units per ml of bile of the untreated chicks and 3.4 105 (80.58 % reduction), 2.5 105 (85.7 % reduction) , 5.4 105 (69.2 % reduction ) and 0.38 105 (97.8 % reduction ) of the respective treated groups, showed AMS significantly (P 0.01) improved AT`s ability to clear the infection, in vivo

Augustine Ngene

George Anosa

Madike Ezeibe

Nnenna Elendu-Eleke

Obianuju Okoroafor

Ogechukwu Chikelu

Okechi Okorie

English

Nature Precedings

 Aluminium – Magnesium Silicate enhances  antibacterial activity of 
Ampicillin  trihydrate, against Salmonella gallinarum   
 
1Ezeibe Maduike, Anosa George, Okorie Okechi,Elendu-Eleke Nnenna, Okoroafor  Obianuju, Ngene 
Augustine, and Chikelu Ogechukwu. 
                                          Department of Veterinary Medicine, 
                                                    University of Nigeria, 
                                                                  Nsukka. 
                              1 Coresponding author (maduikeezeibe@yahoo.com) 
 
Abstract 
 Solutions of different concentrations, of Ampicillin trihydrate (AT)  and of a formulation of  AT  in  
Aluminium Magnesium Silicate (AMS), were  used for sensitivity test  on Salmonella gallinarum cultures. 
Also, S. gallinarum-infected chicks were treated  with ; 10 mg / Kg  (AT), 10 mg / Kg  (AT in AMS),          
7.5 mg / Kg ( AT), 7.5 mg /Kg (AT in AMS). Mean inhibition area, 28.39  mm produced  by  AT  did 
not vary  significantly (P  ) from 26.36  mm produced by AT in AMS. However, 17.5 105  
Salmonella gallinarum culture forming units per ml of bile of the untreated chicks and  3.4  105                
(80.58 % reduction), 2.5  105 (85.7 % reduction) , 5.4  105 (69.2 % reduction ) and 0.38   105 (97.8 % 
reduction ) of the respective  treated groups, showed AMS significantly (P 0.01) improved AT`s ability 
to clear the infection, in vivo. 
Key words: Antibiotic resistance,Synthetic Aluminium – Magnesium Silicate , Stabilization, Salmonella 
gallinarum. 
 Background 
Salmonellosis (typhoid fever) is still a leading  human health challenge in the world. In 2,000 alone, 
typhoid fever caused over 216,500 human deaths1. Though incidence of salmonellosis in humans is 
highest in less developed countries of Asia, Africa and Latin America2, it is still a public health concern 
even in  the USA3. It is  a zoonosis and leads to condemnation of meat at meat inspection. So, it is a 
concern both for  public health and as a cause of loss of investment to livestock farmers and  to meat 
processing factories4.  
 Development of  resistance by  bactria to  antibiotics often  results if the antibiotics fail to ellinate the 
bacterial infections5.For Ampicilline, its antibacterial activity  depends on its bioavailability and on lenght 
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of time it is able to maintain high concentration in blood of  treated animals6. Differences in therapeutic 
actions of drugs made from  same medicinal active ingredients but manufactured by different 
companies are  reported to   be due to interactions of components used in formulating the drugs and on 
stabilizing agents used7. 
Alluminium – Magnesium Silicate (AMS) is used as stabilizing agent for drugs used for treatment of 
diseases of man and of animals8,9. It is safe for use even  in food animals10 and was also  decleared safe 
in  a recent assessment that involved topical and oral administration to laboratory animals11. Its 
molecules  have one of their ends positively charged and the other negatively charged9. These electrical 
charges make AMS, when in solution, to hydrate and form  three dimentional coloidal structures which 
stabilize  drugs` active ingredients9  .   
To stabilize means to protect against destruction. So,if  AMS is used to make a formulation of Ampicillin 
trihydrate, it may protect the antibiotic from being rapidly degraded by metabolic processes. If high 
concentration of Ampicillin is retained in blood of treated animals for a long time, it may lead to better 
clearance of Salmonella  organisms. Enhanced bacterial clearance by antibiotics could reduce incidence 
of antibiotic resistance by bacteria, including the Salmonella  species.  
The natural AMS contains many impurities9.  If it is used at doses  higher than those  currently 
employed, the impurities it contains could lead to  adverse side effects on treated animals or humans. 
To  overcome  this problem posed by impurities in the natural AMS, we reacted Aluminium Silicate and 
Magnesium Silicate to get a Synthetic Aluminium – Magnesium Silicate11. 
Summary of methods 
Ampicillin trihydrate powder and a 2.5 % of the same Ampicillin powder, formulated in a synthetic 
AMS11 were tested  for antibacterial effect, against S. gallinarum, in vitro. One gramm of the 2.5 % 
Ampicillin in AMS and 0.1 g  of the Ampicilin powder were disolved in 1 ml and in 4 ml of  normal saline 
respectively, to obtain Ampicillin concentration of 25 mg / ml in each of the two solutions. The solutions 
were then, each, serially double diluted to get Ampicillin concentrations of 12.5 mg / ml, 6.25 mg / ml, 
3.125 mg / ml and 1.5625 mg / ml for each of the two solutions.The five Ampicillin trihydrate 
concentrations of each of the two solutions were then used for sensitivity test on  pure cultures of S. 
gallinarum. Areas of inhibition on replicate  cultures tested, were measured and their means recorded 
as areas of inhibition for the concentrations of Ampicillin in the two AT drug preparations. Mean 
inhibition diameters for the Ampicillin powder and for the Ampicillin-AMS drug formulation were 
compared by the student T – test. 
In the in vivo experiment, fifty chicks infected with S. gallinarum were  randomly divided into five 
groups. Two groups were treated, for five days, at dose rates of 10 mg  and 7. 5 mg of Ampicillin per Kg 
body weight respectively, with the Ampicillin powder. Two other groups were  similarly treated with the 
Ampicillin–AMS drug formulation while the fifth group served as control. Clinical signs and lessions of 
salmonellosis in the five groups were recorded. Also, S.gallinarum  Colony Forming Units per ml 
(CFU/ml) of bile of chicks in the different treatment categories were determined and tested for 
statistical difference by Analysis Of Variance. 
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 Findings 
Mean diameter of inhibition of S.gallinarum by Ampicillin trihydrate  was 28.30  2.07  with the 
Ampicillin powder  and 26.36  2.05 with  the Ampicillin–AMS preparation (P= 0.0581) . There was no 
mortality even in the untreated  group. However, greenish diarrhae persisted in the untreated group 
while it ceased in all the treated chicks. Livers of the untreated chicks were congested, haemorrhagic 
and friable.Those of the group treated with 7.5 mg / Kg Ampicillin powder had only congestion . The 
group treated with 10 mg / Kg Ampicillin in AMS had haemorrhagic livers. There was no gross lessions on 
livers of the chicks treated with 10  mg / Kg Ampicillin powder and those treated with 7.5  mg / Kg 
Ampicillin in AMS. Salmonella gallinarum load in bile of the control chicks was 17.5  105 CFU / ml while 
those of the groups treated with 10 mg / Kg (Ampicillin),10 mg / Kg ( Ampicillin in AMS), 7.5 mg / Kg 
(Ampicillin) and 7.5 mg / Kg (Ampicillin in AMS) were 3.4  105, 2.5  105, 5.4  105 and 0.38  105 
repectively. Rates of reduction in bacterial load in the respective groups treated  with Ampicillin powder 
and with the Ampicillin-AMS drug formulation were: At 10 mg / kg, 80.5 %  and 85.7 % (P = 0.01 ) and at 
7.5 mg / kg, 69.2 % and 97. 8 %  ( P = 0.01) . 
Discussion 
Detection of S.gallinarum infection  level of  17.5 CFU/ml  of  bile of  chicks that were apparently healthy 
is of publichealth concern, because such infected chicken  can be passed as wholesome for human 
consumption, at meat inspection. 
AMS improved antibacterial action of Ampicillin both at 10 mg / Kg and at 7.5 mg / Kg. However, its 
effect  on 7.5 mg / Kg  was significantly (P=0.01 ) better than its effect on 10 mg / Kg . It is possible that 
by delaying degradation of Ampicillin,the AMS  caused the normaly used dose of Ampicillin (10 mg / Kg) 
to become overdose and thus led to toxicity in treated chicks. Antibiotic toxicity can lead to immune 
supression hence the  relative higher CFU/ml of  bile. Haemorhages on livers of  the chicks treated with 
10 mg / Kg Ampicillin in AMS while lessions were absent in chicks treated with 10mg  / Kg Ampicillin 
alone,even when the 10 mg / kg Ampicillin group  had higher CFU/ml of bile, supports the suspision that 
toxicity and not Salmonella infection caused the relative reduction in effect of the AMS. 
That 10 mg / Kg of Ampicillin powder which is the recomended dose of Ampicillin achieved only 80.58 % 
reduction of the bacterial load  may be one of the causes of  antibiotic resistance against the drug by 
Salmonellae.Clearance of the infection by as much as 97.8 % when treatment was with 7.5 mg /Kg 
Ampicillin in AMS suggests that incorporating Ampicillin trihydrate in AMS may help to reduce incidence  
of  Ampicillin  resistant S.gallinarum.The 2.2 % left, could be elliminated by  immune mechanisms of the 
chicks.  
Use of lower doses of Ampicillin potentiated by AMS, to treat salmonellosis in food animals, has in 
addition to better bacterial clearance as demonstrated in this study, advantages of reduction in cost of 
treatment and reduction in level of antibiotic residues in meat of  treated animals. 
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 AMS could not enhance  ability of Ampicillin trihydrate to inhibit growth of S. gallinarum in vitro, but it 
significantly reduced the bacterial load in bile of treated chicks. This suggests that mechanism by which 
the AMS potentiated antibacterial action of  the antibiotic against the bacterium may not be by 
increasing its potency but by reducing rate of degradation of the drug. Brent et al 6 had already observed 
that when high concentration of Ampicillin was retained in blood of treated animals, improved 
antibacterial effects resulted. Vanderbilt9 reported that AMS is a stabilizing agent. To stabilize means to 
protect against destruction. So, what AMS does may be to protect  drugs against degradation by 
metabolic processes so that high concentrations are retained in the blood for  longer periods after 
treatment. 
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1.Crump,J.A.,Luby,S.P,Mintz,E.D.(2004).The global burden of typhoid fever.Bull. world Organ; 82(5): 346 
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2.Klotchko,A. and Walace, M. R.(2009).Salmonellosis.www.emedicinemedscape.com/article/228174. 
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Aluminium - Magnesium Silicate enhances antibacterial activity of Ampicillin trihydrate, against Salmonella gallinarum

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Aluminium - Magnesium Silicate enhances antibacterial activity of Ampicillin trihydrate, against Salmonella gallinarum

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