Assessment of Antibiotic Susceptibility Pattern on Staphylococcus aureus isolated from Suya (Roasted Meat) and Nunu (Milk) Sold in Jos Metropolis


Assessment of Antibiotic Susceptibility Pattern on Staphylococcus aureus isolated from Suya (Roasted Meat) and Nunu (Milk) Sold in Jos Metropolis

Ejinaka, OR; ; Lote-Nwaru IE; Agbalaka P.I; Ajik, H.

Federal School of Medical Laboratory Science, Jos-Nigeria

Jwanse, R.I

Health and Development Support Programme (Hands), Jos, Nigeria

All correspondence to: Obeta M.U. E-mail:;


The assessment of antibiotic susceptibility pattern on Staphylococcus aureus isolated from Suya (Roasted Meat) and Nunu (Milk) sold in Jos was carried out in Jos Metropolis. This study was aimed at the occurrence of staphylococcus aureus in suya and nunu and its sensitivity to antibiotics. A total of 15 Suya and 15 Nunu sample were collected, the sample were cultured and identified by routine bacteriological method. Prevalence of S.aureus in Nunu was 40% and Suya was 33.3%. The susceptibility profile of staphylococcus aureus isolates from Suya (roasted meat) on an antimicrobial agents revealed a high susceptibility to Gentamycin (80%), Levofloxacin (80%), Rifampin (80%) Norfloxacin (80%) and had high resistance to Chloramphericol (80%), Ciprofloxacin (80%), Amoxil (80%), Ampiclox (80%) and Erythromycin (60%). The susceptibility profile of staphylococcus aureus isolates from Nunu (milk) on an antimicrobial agents revealed a high susceptibility to Gentamycin (80%), Levofloxacin (83.3%), Norfloxacin (83.3%), Erythromycin and Ciprofloxacin (66.7%) respectively, Rifampin and Levofloxacin 50% respectively and had high resistance to Chloramphericol, Amoxil and Ampiclox (66.7%) respectively; Rifampin and Levofloxacin 50% respectively. The S. aureus was present in Suya (Roasted Meat) and Nunu

(Milk) sold in Jos and resistant to some commonly used antibiotics in Jos.

Keywords: Staphylococcus aureus, Antibiotic Susceptibility, Suya, Nunu, Jos.

Staphylococcus aureus is one of the major food borne abdominal cramping, with or without diarrhea. The disease is usually self-limiting and typically resolves within 24 – 48h after onset. Occasionally it can be severe enough to pathogens, frequently causing disease globally as a warrant hospitalization, particularly when infants, elderly result of food ingestion contaminated with or debilitated people are concerned (Argud´ın et al., 2012;
staphylococcal endotoxin (Mendoza, et al., 2010). S.
Mendoza et al, 2013).
S. aureus can cause wide spectrum of infections, ranging from superficial skin infections to severe, and potentially fatal, Jhalka et al., (2014) suggests the contributing factors for invasive disease due to combination of toxin-mediated the low incidence of SFD to include misdiagnosis, virulence, invasiveness, and antibiotic resistance. An improper sample collection in laboratory during important impediment to the control of the Staphylococcus examination, lack of seeking medical attention by the aureus infection is the tendency to gain resistance to almost affected persons, and lack of routine surveillance of all classes of antimicrobial agent (Jhalka et al., 2014).
clinical for S. aureus or its enterotoxins and unavailability
Staphylococcus aureus does not compete well with
of implicated foods for confirmation of laboratory testing
indigenous microbial in raw foods, contamination is
at the time of outbreak.
mainly associated with improper handling of cooked or
processed foods. However, S. aureus is also present in food,
Food handlers such as Suya meat and Nunu vendors are
animals, and dairy cattle, sheep and goats (Larkin et al.,
carrying enterotoxin-producing S. aureus in their noses or
2009). The S. aureus bacteria were then termed methicillin-
their hands which are regarded as the main source of food
resistant S. aureus (MRSA) usually show resistant to many
contamination, via manual contact or through respiratory
antibiotic (Ray et al., 2013). Staphylococcal food
secretions thereby contaminating raw foods, as a result of
poisoning (SFP) is an intoxication that results from the
improper handling of cooked or processed foods, followed
consumption of foods containing sufficient amounts of one
by storage under condition which allows growth of S.
(or more) preformed enterotoxin symptoms of SFP have a
aureus in food and animals. Food that have been frequently
rapid onset (2-8h), and include nausea, violet vomiting,
incriminated in staphylococcus intoxication include meat

and meat products, poultry and egg products, milk and dairy products, salads, bakery products, particularly cream-filled pastries and cakes, and sandwich filling. Salted food products (SFP) such as ham, have also been implicated according to the capacity of S. aureus to grow at relatively low water activity.

S. aureus have been found to survive in materials, clothes, hand nails, ATMs, mobile phones aside skins and nasal areas of the body (Oviasogie et al., 2014; Ekrakene & Igeleke, 2007; Adetona & Olabisio, 2010). It is noteworthy that Suya and Nunu hawkers come in contact with clothes, phones, ATMs and other materials while doing the merchandise without any consideration of washing before handling the food.

SFP is common disease whose real incidence is probably underestimated for a number of reasons, which include misdiagnosis, unreported minor outbreaks, improper sample collection and improper laboratory examination. (Argud´ın et al., 2010)

Nowhere has this issue been of great concern than with the gram-positive bacteria pneumococci, enterococci and staphylococci where multidrug resistance has become a norm among these pathogens. S. aureus is perhaps the pathogen of great concern because of its intrinsic virulence its ability to cause a diverse array of life-threatening infection, and its capacity to adapt to different environment conditions (Argud´ın et al., 2012, Hennekinne et al., 2012). The mortality of S. aureus bacteremia remains approximately 20-40% despite the availability of effective antimicrobial agents (Hassen et al., 2006). S. aureus is now the leading overall cause of nosocomial infections and, as more patients are treated outside the hospital setting is an increasing concern in the community as it is popular practice in Jos where drug vendors and Chemists are patronized without diagnosis or medical advice and such could also lead to increasing resistance to a great number of antimicrobial agents. Inevitably this has left fewer effective bactericidal antibiotics to treat these often life-threatening infections. As rapidly as new antibiotics are introduced, staphylococci have developed efficient mechanism to neutralize them.

In Jos metropolis, most infection are been treated with available drugs in the clinic or just by visiting drug vendors otherwise called Chemists where they are given antibiotics without recourse to medical laboratory diagnosis to identify the disease causing organism and possible susceptible drugs for the disease. Such common antibiotics have been found to be resistant to S. aureus as reported by Wang et al., (2017).

This study is aimed to determine the presence and antibiotics susceptibility profile of pathogenic staphylococcus aureus in Nunu and and Suya meat sold in Jos metropolis.

Materials and Methods

Study Area

The study was carried out in Jos Metropolis, Jos North Local Government Area in locations: Hamaz, Gangare, Railway, Yan Taya and Plateau riders Park. Sample Size / Collection

A total of 15 roasted meats (Suya) and 15 raw milk (Nunu) were collected from the select areas in and around Jos metropolis which includes: Hamaz, Gangare, Railway, Yan Taya and Plateau Riders Park. The Suya (roasted meat) and Nunu samples were obtained 3 each from every point of sales in Hamaz, Gangare, Railway, Yan Taya and Plateau riders Park into a sterilized universal bottle, packed into a polythene bags, and transported into the medical laboratory for analysis. While the Nunu sample were also collected in sterile polythene bags and transported in an icebox and transported to the Federal School Research Laboratory, Jos for analysis within 3 hours.

Isolation of Staphylococcus Aureus in Nunu and Suya 1mL of each sample was transferred to flask containing 9ml of peptone water for enrichment. According to ISO 6888, the plates were incubated under aerobic conditions at 370C for 24hr and those that yielded growth were subjected to another 24hr incubation for susceptibility assessment.

The total counts were carried out using nutrient agar. In serial dilution preparation, 1.0g of sample was aseptically, transferred into 9.0ml of diluted water and homogenized by vortex. Subsequent serial dilutions up to 10-5 were made in line with Kalalou et al. (2004). The enumeration of microorganisms in the samples was by the pour plate technique. At the end of the incubation, resultant microbial colonies (staphylococcus aureus) were counted.

Identification of Staphylococcus Aureus from Nunu and Suya

Pure isolates of microorganism grown on the different chocolate agar plates were further identified biochemically using Cowan and Steel (1974) technique using oxidase, coagulase, maltose, glucose and gram’s staining. The staphilococcus aureus were the only organisms isolated from suya meat and nunu samples obtained from the food vendors in Jos metropolis as identified from the samples.

Antibiotic Susceptibility Test of the Isolates of Staphilococcus Aureus

All S. aureus isolates were screened for multi-drug-resistance using disc diffusion in line with Bauer et al., (1966). This was performed on nutrient agar plates. Furthermore, the antibiotic susceptibility pattern of S. aureus strains was determined by disc diffusion method for Ciprofloxacin (10mcg), Gentamycin (10mcg), Norfloxacin (10mcg), Erythromycin (30mcg), Streptomycin (30mcg), Levofloxacin (20mcg), Chloramphenicol (30mcg), Amoxil, Ampiclox and Rifampin. Chloramphenical, Erythromycin and Norfloxacin susceptibility was determined by the e-test according to the manufacturers’ guidelines (Biometriux, France).

The diameter of the zone of inhibition produced each antibiotic disc was measured, recorded and the isolates were classified as “resistant”, “intermediate” and “sensitive” based on the standard interpretative chart updated according to the CLSI (2015). Multi-resistance was defined by resistance of the strain to at least three antibiotic agents.




Prevalence of Staphylococcus aureus from suya (roasted meat) sample

S/N Meat sample S. aureus x(y) Cell count Percentage
prevalence (%)
1. A 2(3) 7 x 1010 66.7
8 x 1010
2. B 1(3) 4 x 1010 33.3
3. C 1(2) 9 x 1010 50.0
4. D 0(2) 0.0
5. E 1(5) 5 x 1010 40.0
Total 5(15) 33.3

Key: X = Number Positive, Y = Number of sample examined, A = Hamas, B = Gangare, C = Rail Way, D = Yantaya, E = Plateau riders

Prevalence of Staphylococcus aureus from Nunu in Jos Metropolis

S/N Meat sample S. aureus x(y) Cell count Prevalence (%)
1. A 2(3) 6x 1010 66.7
8 x 1010
2. B 1(2) 4 x 1010 50.0
3. C 0(5) 0.0
4. D 2(3) 4 x 1010 66.7
7 x 1010
5. E 1(2) 3 x 1010 50.0
Total 6(15) 40.0

Key: X = Number Positive, Y = Number of sample examined, A = Hamas, B = Gangare, C = Rail Way, D = Yantaya, E = Plateau riders

Antibiotic Susceptibility Profile for Suya (Roasted Meat)

Antibiotics Disc t Samples Percentage Percentage
Conten A2 B1 C1 D3 E1 Resistance Sensitive
(ng) (%) (%)
Norfloxacin (NB) 10 R S S S S 20 80
Chloramphenicol (CH) 30 R S R R R 80 20
Ciprofloxacin (CPF) 10 R R S R R 80 20
Erythromycin (E) 30 S R R R S 60 40
Levofloxacin (LV) 20 R S S S S 20 80
Ampiclox (AML) 20 R R S R R 80 20
Amoxil (AML) 20 R R S R R 80 20
Gentamycin (CN) 10 R S S S S 20 80
Rifampin (RD) 5 S S R S S 20 80

Key: S = Sensitive, R = Resistance


Assessment of Antibiotic Susceptibility Pattern on Staphylococcus…

Antibiotic Susceptibility Profile for Suya (Roasted Meat)

Antibiotics Disc t Samples Percentage Percentage
Conten A2 B1 D2 E1 B3 E2 Resistance Sensitive
(ng) (%) (%)
Norfloxacin (NB) 10 S S R S S S 16.67 83.34
Chloramphenicol (CH) 30 R R S S R R 66.67 33.34
Ciprofloxacin (CPF) 10 S R S S S R 33.34 66.67
Erythromycin (E) 30 S R S S S R 33.34 66.667
Levofloxacin (LV) 20 S R R S R S 50.00 50.00
Ampiclox (AML) 20 R S R R S R 66.67 33.34
Amoxil (AML) 20 R R R R S S 66.67 33.34
Gentamycin (CN) 10 S S R S S S 16.67 83.34
Rifampin (RD) 5 S S R R R S 50.00 50.00

Key: S = Sensitive, R = Resistance


Staphylococcus aureus is an important health care and community acquired infection in every region of the world (Wang et al., 2017). This studies shows that Staphylococcus aureus is prevalent in Suya (33.3%) and Nunu (40%) and could possess a potential health hazard (Sofos, 2008) to consumers in Jos Metropolis. Studies on isolation and antibiotic susceptibility frequency of isolation of S. aureus isolates from meat and milk may be due to the possible susceptibility of S. aureus isolates from Suya and Nunu to Levofloxacin, Erythromycin, Norfloxacin, Gentamycin and Rifampin as observed in this study. However, this report was not different from other studies reported by Waters et al. (2011). The high susceptibility of S. aureus to these antibiotics may be due to high costly or injectable forms and the possibility of abuse of such antibiotics may be low. The low susceptibility of chloramphenicol, amoxil, ampiclox observed in this study was not different from the other studies reported by Le et al., (2003). The low susceptibility of S. aureus to antibiotics mentioned may be due to inappropriate use of antibiotics without doctor’s prescription and inclusion of antibiotics in animal feeds as growth promoter (Le et al., 2003). From this study, it was however observed that the frequency of isolation of S. aureus observed in this study was high and isolates were more susceptible to flouroquinolones and aminoglycosides. In view of this, such drugs may be useful for treatment of staphylococcal infections, but there is a need to conduct appropriate medical laboratory diagnosis to find out the causative organism S. aureus for example before treatment especially in Jos Metropolis. The indiscriminate use of antibiotics/antimicrobials agents for prophylactic as well as other therapeutic purpose could be the reasons for increased antimicrobial resistance of S. aureus in animals and humans.


Staphylococcal food poisoning (SFP) is a major concern in public health programs worldwide. S. aureus may be present in cow milk as a result of milk collection from the animal suffering from disease condition and excreting S. aureus in milk or due to unhygienic conditions during production, processing, storage and handling of milk products, which are the main causes of food borne

diseases. The result of this study clearly indicated that some Nunu and Suya available in the Jos metropolis were contaminated with S. aureus, which could pose a risk of food poisoning to Jos metropolis. Thus, more hygienic preventive measures are required to reduce the bacterial contamination, so as to increase the wholesomeness of these Nunu and Suya. The study also revealed common antibiotics used in Jos which are resistant to S. aureus. This study highlights the need for continuous surveillance of antibiotic sensitivity pattern of staphylococcus aureus with a view to selecting appropriate therapy. This study also recommends that:

  1. All Suya meat and Nunu vendors should imbibe adequate hygiene measures while handling the food products
  2. The Suya and Nunu vendors should use nose masks while processing handling their products
  3. The Suya and Nunu vendors in Jos metropolis should avoid using dirty rags to clean their hands while processing and dispensing their products to the public


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