International Educational Applied Scientific Research Journal ISSN (Online): 2456-5040 Volume: 1 | Issue: 3 | December 2016
ANTIBIOTICS SUSCEPTIBILITY PATTERN OF COAGULASE NEGATIVE STAPHYLOCOCCI ISOLATES FROM ORTHOPAEDIC PATIENTS Obajuluwa A.F1, Onaolapo J.A2, Olayinka B.O.2, Adeshina G.O.2 1
Department of Pharmaceutics and Pharmaceutical Microbiology, Kaduna State University, Kaduna, Nigeria. 2 Department of Pharmaceutics and Pharmaceutical Microbiology, Ahmadu Bello University, Zaria, Nigeria.
ABSTRACT A total number of 74 coagulase negative Staphylococci were isolated from orthopaedic patients in Ahmadu Bello University Teaching Hospital, Zaria, Nigeria. They were further characterized into various Staphylococci species using API STAPH identification kit: Staph xylosus (31.1%), Staph lentus (10.8%), Staph hominis (10.8%), Staph cohnii cohnii (5.4%), Staph epidermidis (4.1%) others were Staph cohnii ureal., Staph hyicus, Staph lugdunensis (2.7% each) Staph caprae , Staph capitis, Staph haemolyticus, Staph scuiri, Staph chromogenes and Staph warneri (1.4% each). Microcossus spp was 8.2% while 13.5% isolates were undetermined. Kirby Baurer disk method was used for the antibiotics susceptibility test, the result showed gentamicin and ciprofloxacin to be most active (96.6%), followed by vancomycin (93.1) and pefloxacin (87.9). The isolates were resistant to ampicillin (96.6), amoxicillin clavulanic acid (65.5%), clindamycin 41.4%). The aim of this study is to classify the coagulase negative Staphylococci isolates into species and to determine their antibiotic susceptibility Key words: coagulase negative Staphylococci, antibiotics, susceptibility. common forms of osteomyelitis attributable to coagulase-negative staphylococci infection are sternal osteomyelitis, following cardiothoracic surgery, and infection of bone surrounding a prosthetic joint (Chandrasekar and Brown, 1994).
Introduction Staphylococci are members of the family Micrococcaceae. They are Gram-positive, catalase-positive and occur singly and in irregular grapelike clusters, a description from which is the origin of their name. Staphylococci are broadly divided into a group that produce coagulase (S. aureus) and those that do not (Levinson, 2010). Most of the coagulase-negative staphylococci associated with clinical disease are common inhabitants of the skin and mucous membranes. S. epidermidis is the most prevalent species, accounting for approximately 60-70% of all coagulase-negative Staphylococci on the skin. Coagulase-negative staphylococci are frequently associated with nosocomial infections, 41% of the time when bacteremia is present, and of these many are line infections (Favre et al, 2005).
One of the characteristics of CoNS is their resistance to multiple antimicrobial agents commonly used for the treatment of staphylococcal infections. Since the 1970s, it has been suggested that CoNS are of great importance as true pathogens, and they have become a common cause of a wide variety of infections (Dubois et al., 2010; Otto, 2009). Materials and Methods Isolation and Classification of Staphylococci strains After obtaining the patients’ consent, all staphylococci used were isolated from the wounds, beds, and skin of orthopaedic patients in the orthopaedic ward of Ahmadu Bello University Teaching Hospital Zaria, Nigeria. Using sterile swab sticks 114 samples were aseptically collected and purified. Biochemical tests including coagulase test was used to isolate the coagulase negative Staphylococci strains from the coagulase positive. The CoNS isolates were further characterized into species using API STAPH identification kit (bioMerieux, Inc.,Durham, NC).
Host factors that predispose to coagulase-negative staphylococci infections include immunosuppression and the presence of a medical device. However, there are some species of coagulase-negative staphylococci that have been associated with particular infections other than immunosuppression or a medical device, implanted foreign bodies such as vascular – access catheters, prosthetic joints and other orthopaedic hard ware (Karsten et al, 2014). For example, S. saprophyticus accounts for up to 10% of uncomplicated urinary tract infections in young women (Innes et al, 1994; Peters and Clissold, 1992). S. schleiferi, S. lugdunensis and S. haemolyticus are associated with native valve endocarditis (John and Harvin, 2007; Kanafani and Telavancin, 2006). S. lugdunensis when isolated from an otherwise sterile bodily site is almost always a pathogen (Hellbacher et al, 2006; Viganego et al, 2007). The two most
Antibiotics susceptibility test Antibiotics susceptibility test of the characterized CoNS strains were determined by the Kirby Bauer disk diffusion method on Mueller-Hinton agar (Oxoid, Basingstoke) according to the Clinical and Laboratory Standards Institute (CLSI) (Clinical and Laboratory Standards Institute., 2013). 4