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E-International Scientific Research Journal, VOLUME – IV, ISSUE- 1, 2012, ISSN 2094-1749

ANTIMICROBIAL SUSCEPTIBILITY PATTERN OF Staphylococcus aureus ISOLATED FROM SURGICAL WOUND OF PATIENTS IN JOS UNIVERSITY TEACHING HOSPITAL, NORTHCENTRAL NIGERIA Idighri, M. N.1 and Nedolisa, A.C.2Egbujo, E.C3 1

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Solat Women Hospital, Jos Plateau State Nigeria. Department of Microbiology Jos University Teaching Hospital. 3 Meena Histopathology Laboratory Services, Jos.

Author for correspondence: [email protected]

ABSTRACT Antimicrobial susceptibility pattern of Staphylococcus aureus isolated from 200 cases of surgical wounds of patients attending Jos University Teaching Hospital were examined. Out of the 200 samples examined Staphylococcus aureus was isolated in 61(30.5%). Others isolated were Proteus spp 38(19%), Pseudomonas aeruginosa 34(17.5%), Escherichia coli 29(14.5%), Klebsiella spp 25(12.5%), Streptococcus spp 3(1.5%) and Alkagenes 1(0.5%). No bacteria were isolated in nine (9) samples. The age group with the highest number of isolate was (21-30) with a frequency of 50%. Females (32%) were more infected than male (30%). The overall profile of susceptibility pattern showed that Gentamycin and Erythromycin were more sensitive 89% and 74% respectively and Penicillin was the least sensitive 26%. The result of the study shows that Gentamycin and Erythromycin are more effective in the management of Staphylococcus aureus in this locality.

Keywords: Staphylococcus aureus, surgical wounds, INTRODUCTION: Wound is defined as a bodily injury caused by physical means with disruption of the continuity of structures (Baker, 1980). Micro- organisms which are responsible for wound infections depends on the surgical site, the study population and antimicrobial use within the hospital. The most common organism in wound infection is Staphylococcus auerus (Taylor, 1992 and Buwembo, 1990).Staphylococcus auerus remains a significant cause of mortality and morbidity in tropical countries (Rasoul, et al, 2010; Onile et al, 1985). The Centers for Disease Control and Prevention estimates that approximately 500,000 surgical site infections occur annually in the United States (Perencevich et al., 2003). If this figure is anything to go by, it then means that in third-world country

like Nigeria where such health statistical data are hardly documented calls for attention. Apart from the increased discomfort to the patient and damage to certain surgical procedures, the 1


duration of hospital stay is prolonged, this adding to the financial burden of surgical management (Hiramatsu et al, 1997). More recently, the problem has further been compounded by the emerging cases of microbial resistance to Staphylococcus aureus (Akpaka et al,2006 and Douglas, et al., 1998). The aim of the present study is to establish the incidence of Staphylococcus aureus in surgical wounds, among male and female and its antibiotic sensitivity pattern to various antibiotic in different age groups in this locality. Staphylococcus aureus is a gram-positive cocci, catalase and coagulase positive bacterium.

MATERIALS AND METHOD: This study was conducted in Jos University Teaching Hospital (JUTH) Plateau state Nigeria. A total of 200 specimens obtained from patients who had undergone surgical operations in the various surgical wards of the hospital comprising Casualty, Orthopedics, appendicitis and Prostate operation. Patients were enrolled after obtaining informed consent from them or guardians/attendants. Each specimen was accompanied by such information as patients’ name, hospital number, ward number, sex, age, date and clinical prognosis on admission, site and type of surgery and antibiotic prophylaxis if any. Samples were collected with assistance of medical officers or ward nurses during ward-rounds and before dressing. The specimens (Pus, Exudates or aspirates) were aseptically obtained from surgical sites using sterile swab stick and sterile syringe. The specimens were cultured on blood agar, chocolate agar and MacConkey agar plates. The chocolate plate was incubated with increased carbon dioxide jar at 370 in the incubator. Culture plates were examined after 24 hours incubation for growth and culture characteristic for identification of the isolate by gram stain, catalase and coagulase testing according to standard bacteriological procedures (Cheesbrough, 1993) each confirmed Staphylococcus aureus isolate was prepared in peptone water to match 0.5 Macfarand turbidity standards. A sterile well dried nutrient agar plate was inoculated by flooding with 6hours incubated broth. Excess was drained off the plate, allowed to dry and using a sterile forceps the appropriate grampositive sensitivity disc was placed on it pressed gently to ensure contact with medium. The zones of inhibition were measured and compared with national committee for clinical laboratory standards guidelines (NCCLS, 1995).

RESULTS The following results were obtained. Out of 200 patients with surgical wound attending Jos University Teaching Hospital that were examined for bacterial growth and antibiotic susceptibility pattern. The following results were obtained.

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Table I. The frequency of Staphylococcus aureus and other bacterial isolates in Jos University Teaching Hospital Bacterial species Staphylococcus aureus Pseudomonas aeruginosa Klebsiella specie Proteus specie Echerichia coli Streptococcus specie Alkaligenes specie Sterile culture(No growth) Total

No. of Isolates (%) 61(30.5) 34(17.0) 25(12.5) 38(19.0) 29(14.5) 3(1.5) 1(0.5) 9(4.5) 200(100)

Table II. The Age group Distribution of the Staphylococcus aureus Isolates in Jos University Teaching Hospital Age Range (yrs) Positive (%) 0-10 11-20 21-30 31-40 41-50 51-60

Number Tested

Number

45 76 20 20 24 15

17(38) 20(26) 10(50) 8(40) 2(8) 4(27)

Table III. Distribution of Staphylococcus aureus among Male and Female surgical patients in Jos University Teaching Hospital Sex Positive (%) Male Female Total

Number Tested

Number

116 84

34(30) 27(32)

200

61

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Table IV. Age group Susceptibility patterns of Antibiotics tested on Staphylococcus aureus isolated in Jos University Teaching Hospital Age CLO 0-10 7(41) 11-20 11(55) 21-30 5(50) 31-40 6(75) 41-50 1(50) 51-60 3(75)

Isolates

PEN

GEN

CHL

AMP

TE

ERY

STR

17

4(24)

12(71)

4(24)

8(47)

11(65) 12(71)

10(59)

20

6(30)

19(95)

13(65)

6(30)

14(70) 15(75)

9(45)

10

3(30)

10(100)

5(50)

4(40)

7(70)

8(80)

5(50)

8

3(38)

7(88)

6(75)

6(75)

4(50)

5(63)

6(75)

2

0(0)

2(100)

1(50)

4

0(0)

4(100)

4(100)

2(100)

1(50)

2(50)

3(75)

1(50)

0(0)

4(100)

2(50)

Key: PEN – Penicillin; GEN – Gentamicin; CHL – Choramphenicol; AMP – Ampicillin; TE – Tetracycline; ERY – Erythromycin; STR – Streptomycin; CLO – Cloxacillin Table V: Antibiotic sensitivity and resistant pattern of Staphylococcus aureus in Jos University Teaching Hospital

Type of Antibiotic

No. tested

No. sensitive

Penicillin

61

16

Gentamicin

61

Choramphenicol

61

Ampicillin

61

%Sensitive

%Resistant

26

74

54

89

11

33

54

46

28

46

54

Tetracycline

61

40

66

34

Erythromycin

61

45

74

26

Streptomycin

61

32

53

47

Cloxacillin

61

33

54

46

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DISCUSSION This study shows the occurrence of Staphylococcus aureus from surgical wounds of in –patients admitted in Jos University Teaching Hospital, North Central Nigeria in which two hundred (200) samples were analyzed, table 1 shows the frequency of occurrence of Staphylococcus aureus and other bacterial isolates in pure cultures. Staphylococcus aureus had the highest number of occurrence 30.5%(61) while Streptococcal species and Alkligenes species had the least frequency occurrence of 1.5%(3) and 0.5%(1) respectively. These findings agree with previous findings (Amrita Shriyan, et al.,2010; Anguzu and Olila, 2007) who reported that the most single cause of post-operative wound infection was Staphylococcus aureus. A high frequency of occurrence was recorded among the female patients 32% than male patients with 30% (Table III). The difference seems to be too small although statistical difference was not determined. However, the result shows an increased prevalence of the gram negative bacterial organism in the surgical wounds analyzed compared to the gram positives. This is in line with other findings (Anguzu and Olila, 2007; Anbumani et al.,2006), indicating increase or equal prevalence of gram negative to gram positive organisms in hospital wound infection. Hence, suggesting the need to also look at antibiotic susceptibility pattern of gram negative organisms in future studies. Staphylococuss aureus has been documented to be most liable to infect new born babies, surgical patients, old and malnourished persons and patients with diabetes and other chronic disease (Tou et al, 1995).Table II which shows that age group of 21-30 has the highest percentage of isolate of 50%, and followed closely by the age group of 31-40 with 40%. This result disagrees with the findings of Law and Wrong, (1980) that patients in the age group greater than 40 years were associated with higher surgical wound infection and that of (Nwankwo and Nasiru, 2011) that observed higher frequency in age group (0-10) and older children. Although this study concentrated on surgical wound infections only while (Nwankwo and Nasiru, 2011) worked on isolation of Staphylococcus aureus on different samples. However, a relatively high positive culture was equally observed in patients within the age group of 0-10years (36%) in this study. Looking at Table IV and V, the antibiotic susceptibility test revealed that in all the age groups, the isolates showed a marked sensitively to Gentamycin followed by Erythromycin. Staphylococcus aureus sensitivity to Gentamycin in this study was 89% which agrees with (Nwankwo and Nasiru, 2011; Paul et al 1982 and Ndip et al 1997). A marked resistance to some of the commonly used and relatively safe antibacterial agents was also observed (TableIV and V), for example Staphylococcus aureus shows some level of resistance to all the antibiotics used with penicillin(Table V) having the highest resistance in this work which could be attributed to interplay of many factors ranging from abuse of drugs by patients, unrestricted use of broad spectrum antibiotics for prophylactic measures prior to surgery or operatively without resorting to sensitivity testing. The compromise by some surgeon substituting antibiotic prophylaxis and chemotherapy for basic surgical principle has been revealed. For example, it was noted that out of 218 post-operative patients studied 180(82%) received antibacterial agents immediately postoperatively, 120(68.33%) of which receive antibacterial agents containing Cloxacillin (NjokuObi and Ojiegbe 1986). They therefore suggested that such practice while necessary, might seriously affect the number and the type of organisms isolated from wound infections and their antibiotic susceptibility patterns. The resistance of Staphylococcus aureus to Penicillin and other antibiotics can be due to the production of beta-lactamase or possession of extra chromosomal 5


factor, R-factor or plasmids. In this study, beta-lactamase was not tested for in the Staphylococcus aureus strains isolated. It is essential that this should be done from time to time to determine the best drug for treatment. Several workers have observed that the prevalence of Beta-lactamase producing Staphylococcus aureus vary greatly in different countries and at different time. In the United State, Nafcillin resistant Staphylococcus aureus accounted for 0.1% of the isolates in 1970s while in the 1980s, it constituted 10-30% of isolates from nosocominal infection (Basker et al., 1980) and (Haley et al., 1982). In contrast in Denmark Nafcillin resistant Staphylococcus aureus constituted 40% of isolates in 1970s but only 10% in the 1980 without notable changes in the use of Nafcillin or other Beta-lactamase stable antimicrobial drugs.

REFERENCE: Amrita S, Sheetal R Narendra N. (2010). Aerobic Micro-Organisms in Post-Operative Wound Infections and Their Antimicrobial Susceptibility Patterns. Journal of Clinical and Diagnostic Research, (4):3392-3396. Anbumani N, Kalyan J, Mallika M(2006). Epidemiology and Microbiology of Wound Infections. Indian Journal for the Practising Doctor. Vol. 3, No. 5 (2006-11 - 2006-12) Anguzu J.R and Olila, D (2007). Drug sensitivity patterns of bacterial isolates from septic postoperative wounds in a regional referral hospital in Uganda. African Health Sciences Vol 7.,148154. Baker (1980). Medical Microbiology Techniques staining pp. 213-234 Basker M.J. Edmonden R.A, Sutherlande R. (1980) Comparative stabilities of Penicillin and Cephalosporins to Staphylococcus beta-lactamase and activities against Staphylococcus aureus. J. Antimicrobal chemotherapy 6: 34-41. Cheesbrough M. Medical laboratory manual for Tropical countries. Vol 2, 1993, pp225-227 Douglas S.K, David C.C.; Charles W.S and Allen B.K (1998). Association of Bordeline Oxacillin-Susceptiblity Strains of Staphylococcus aureus with Surgical Wound Infections. Journal of Clinical Microbiology. P.219-222. Hairamatus K, Hanaki H, Ino T, Yabuka K, Oguri T, Tenover F.C. (1997). Methicillin-resistant Staphyloccus aureus clinical strain with reduced vancomycin susceptibility. Journal of Antimicrobial Chemotherapy. 40:135-136 Haley R.W (1982). The emergence of methicilline resistant Staphylococcus aureus infection in United States Hospital. Ann. International Medicine. 97:297 Lau W.Y and Wong S.H (1981): Randomized, prospective trial of tropical infection. High risk factor American Journal of Surgery Vol. 142:393-7

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NCCLS (1995). Perfomance standards for antimicrobial susceptibility testing, Sixth international supplement. NCCLS documents M100-S6,Villanova, Pa. Ndip R.N, Ebah L.M.E, Onile B.A.( 1997). Antibiogram of Staphylococcus aureus from clinical Syndromes in Ilorin. Nigeria. J Med Lab Sci. 6:24-26. Njoku-Obi A.N.U and Ojiegbe G.C. (1989): Resistance patterns of bacterial isolated from wound infections in a University Teaching Hospital West African. Journal of Medicine. Vol. 8(1): 185189 Nwankwo E.O and Nasiru M.S (2011). Antibiotic sensitivity pattern of Staphylococcus aureus from clinical isolates in a tertiary health institution in Kano, Northwestern Nigeria. Pan African Medical Journal. 8:4 Onile B.A, Odugbemi T.O, Nwofor C.( 1985). Antibiotic susceptibility of Bacterial agents of Septicemia in Ilorin. Nig Med Pract. 9(4): 16-18 Patrick E. A, Shivnarine K, William H .S and Michele M (2006). Prevalence and antimicrobial susceptibility pattern of methicillin resistant Staphylococcus aureus isolates from Trinidad& Tobago. Annals of Clinical Microbiology and Antimicrobials, 5:16 Paul M.O, Aderibie D.A, Sule C.Z.( 1982). Antimicrobial sensitivity patterns of hospital and non hospital strains of Staphylococcus aureus isolated from nasal carriers. J Hyg Camb. 89:253-260. Perencevich E.N, Sands K.E, Cosgrove S.E,(2003). Health and economic impact of surgical site infections diagnosed after hospital discharge. Emerg Infect Dis.9(2):196-203. Rasoul S. Hossein K, Mehrnaz R, Alireza A and Kheirollah G (2010).Antimicrobial Susceptibility Pattern of Staphylococcus aureus Strains Isolated from Hospitalized Patients in Tehran, Iran. Iranian Journal of Pharmaceutical Sciences. 6(2):125-132

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