ANTIMICROBIAL SUSCEPTIBILITY OF
Streptococcus species IN BLOOD
OF SLAUGHTERED PIGS (Sus domesticus) FROM
SELECT
BACKYARD FARMS IN RODRIGUEZ, RIZAL
By Rommel A. Anastacio
March 2022
• Streptococcus suis is a commensal of the respiratory tract and
commonly seen in tonsil of a healthy swine.
• It is facultative anaerobe, gram positive non- motile coccus that
produces α- hemolysis in blood agar.
• causes death by septic shock or meningitis and purulent arthritis
occurred among post weaned piglets
• According to the article antimicrobial resistance of Streptococcus spp.
and Salmonella species isolates has increased from select swine and
poultry farms in region Ⅲ and Ⅳ in the Philippines.
• In swine backyard farms in regions Ⅲ and Ⅳ of the
Philippines the improper usage of antibiotics such as
amoxicillin, penicillin G and erythromycin which are
frequently used in treating common diseases in swine has
increased the antimicrobial resistance of the Streptococcus
suis
Statement of the Problem
This study was conducted to determine the antimicrobial
susceptibility of Streptococcus species isolates in the blood of
swine collected from select backyard farms in Rodriguez,
Rizal. Specifically, it sought to answer the following
questions:
1. What will be the frequency of Streptococcus species
isolated in the blood of slaughtered pigs from select
backyard farms from Rodriguez, Rizal?
2. Will frequency antimicrobial susceptibility of Streptococcus
species isolated in the blood of slaughtered pigs vary among
amoxicillin, erythromycin, lincomycin, tetracycline and
trimethoprim sulfamethoxazole?
3. Will there be significant difference in the frequency
antimicrobial susceptibility of Streptococcus species
isolated in the blood of slaughtered pigs to amoxicillin,
erythromycin, lincomycin, tetracycline and trimethoprim
sulfamethoxazole?
4. Will frequency susceptibility of Streptococcus species to
amoxicillin, erythromycin, lincomycin, tetracycline and
trimethoprim sulfamethoxazole in the blood of slaughtered
pigs vary among backyard farms?
Hypotheses of the Study
1. The frequency antimicrobial susceptibility of Streptococcus species
isolated from the blood of slaughtered pigs does not vary among
amoxicillin, erythromycin, lincomycin, tetracycline and trimethoprim
sulfamethoxazole.
2. There is no significant difference in the antimicrobial susceptibility of
Streptococcus species isolated in the blood of slaughtered pigs to
amoxicillin, erythromycin, lincomycin, tetracycline and trimethoprim
sulfamethoxazole
3. The frequency antimicrobial susceptibility to amoxicillin,
erythromycin, lincomycin, tetracycline and trimethoprim
sulfamethoxazole of Streptococcus species isolated in the blood of
slaughtered pigs does not vary mong backyard farms.
Significance of the Study
• The study tried to determine the antimicrobial susceptibility
of Streptococcus species isolates in the blood of pigs from
select backyard farms in Rodriguez, Rizal
• The study will inform the consumers of pig blood, about the
importance of food safety specially the presence of S. suis
and the disease it causes in humans.
• This study will benefit swine veterinary practitioners who
have encountered S. suis as the cause of respiratory infections
in pigs and discover the infection no longer responds to
antibiotic treatment.
• Slaughterhouse personnel who are exposed to S. suis. and
veterinary students who are performing similar studies and
farm owners will be informed on the public health importance
of S. suis will also benefit from this study.
Scope and Limitations of the Study
The study was performed to determine the antimicrobial
susceptibility of Strep. species isolated in pig blood from select
backyard farms in Rodriguez Rizal. One hundred ml (100ml).
of fresh blood sample was collected aseptically, direct from the
swine while it was bled, placed in a sterile screwcap plastic
bottle, arranged in an ice box immediately and labeled.
Twenty (20) fresh pig blood samples came from three (3)
select backyard farms when the pigs were slaughtered at
Montalban Slaughterhouse at Rodriguez Rizal.
The fresh swine blood sample were submitted to BioAsset
Veterinary Microbiology Diagnostic laboratory in Batangas for
purification and identification of Strep. species isolates based
on typical colony characteristics in BHI blood agar, Gramstaining and biochemical tests. The Strep. species isolates
were subjected to Kirby-Bauer disc diffusion method to
determine their antimicrobial susceptibility to amoxicillin,
erythromycin, lincomycin, tetracycline and TMPS.
The area of zone of inhibition was measured using Vernier
caliper to the nearest mm. Pearson square method was used to
determine if there is significant difference in the frequency
susceptibility of Strep. species to amoxicillin, erythromycin,
lincomycin, tetracycline and trimethoprim sulfamethoxazole.
Time and Place of Study
The study was conducted from March 2021 to March 2022.
The writing of the manuscript was done at the residence of the
author. The collection of fresh swine blood samples was
performed at a select slaughterhouse in Rodriguez, Rizal.
Streptococcus species were isolated, identified and subjected to
Kirby Bauer disk diffusion method at the at BioAssets
Veterinary Research and Diagnostic Laboratory in NDN
Building, 34 Pres. J.P. Laurel Highway, San Roque, Santo
Tomas Batangas. Finalization, analysis and interpretation of
the results was done under the supervision of the thesis adviser,
Dr. Edelmira P. Guno.
Summary
• This study was conducted to determine the antimicrobial
susceptibility of Streptococcus species isolates in the blood of
pigs from select backyard farms in Rodriguez, Rizal. Twenty
(20) blood samples were collected aseptically from pigs from
three select backyards farms at the slaughterhouse in
Rodriguez, Rizal. The pig blood samples were submitted to a
Microbiology Diagnostic Laboratory in Batangas for isolation
and identification of the Streptococcus species.
• The purified isolates of Streptococcus species from pig blood
samples were then subjected to antimicrobial susceptibility
test using amoxicillin, erythromycin, lincomycin, tetracycline
and TMPS. The antimicrobial susceptibility was based on the
diameter of zone of inhibition, measured to the nearest
millimeter. The levels of antimicrobial susceptibility,
frequency and percentage frequency were gathered and
recorded. Then it was classified as sensitive (S), intermediate
(I) and resistant (R).
• Based on the results of the study, out of twenty (20) pig blood
samples collected, three (3) were isolated and identified as
Streptococcus species, with one isolate from each of the three
backyard farms. All three isolates were sensitive to
amoxicillin, and all are resistant to lincomycin and TMPS,
one (1) species from farm A and B are resistant to
erythromycin, one (1) from farm A and C were both resistant
to tetracycline and one was intermediate to erythromycin and
one was intermediate to tetracycline.
• Based on the results there is a significant difference in the
frequency of antimicrobial susceptibility of Streptococcus
species isolated from pig blood. The Streptococcus species
isolated from backyard farms are all sensitive to amoxicillin
but the other antimicrobials are no longer effective against the
isolates.
Conclusion
1. The frequency of antimicrobial susceptibility of
Streptococcus species. isolates from the blood of
slaughtered pigs vary among amoxicillin, erythromycin,
lincomycin, tetracycline and trimethoprim
sulfamethoxazole. The null hypothesis is rejected.
2. There is a significant difference in the antimicrobial
susceptibility of Streptococcus species isolates to
amoxicillin, erythromycin, lincomycin, tetracycline and
trimethoprim sulfamethoxazole from the blood of
slaughtered pigs. The null hypothesis is rejected.
3. The antimicrobial susceptibility of Streptococcus species
isolates in the blood of slaughtered pigs to amoxicillin,
erythromycin, lincomycin, tetracycline and trimethoprim
sulfamethoxazole does not vary among backyard farms. The
null hypothesis is accepted.
Recommendation
1. The three swine backyard farms should use amoxicillin to
treat Streptococcus suis infections in their herd and avoid
the use of the antimicrobial drugs such as erythromycin,
lincomycin, tetracycline and trimethoprim
sulfamethoxazole because the bacteria isolated are already
resistant.
2. Backyard farmers must follow the veterinarian
recommendations on the use of antimicrobial drugs in the
treatment of diseases in their swine herd and must follow
proper use of antibiotics to prevent antimicrobial resistance.
3. Further study on isolation of Streptococcus suis from
meningeal swab and cerebral spinal fluid from cases of
meningitis and joint fluid from arthritis cases in pigs.
4. Future researchers are advised to gather larger sample size
from pigs from various slaughterhouse in the Philippines
for more results to isolate Streptococcus suis and subject
them to antimicrobial susceptibility test.
5. Buyers and consumers are encouraged to cook the pig blood
thoroughly. Recommended to heat blood at least
100oC/10minutes to avoid food poisoning.