ABSTRACT
The threat posed by staphylococcal strains associated infections in the global village is becoming a problem of note. Antimicrobial resistance calls for adequate preventive and control measures to reduce transmission even among the perceived healthy students who might constitute a population of healthy carriers. This study was carried out with the aim to evaluate the prevalence and antibiotic susceptibility pattern of staphylococcal strains isolated form nasal mucosa (nose) and skin form healthy students of Michael Okpara University of Agriculture, Umudike. A total of 50 clinical specimens comprising of nose and skin swab were collected from five (5) hostels cultured on mannitol salt and blood agar. Staphylococci strains were identified based on their conventional cultural characteristics, gram staining reaction and standard biochemical tests. All the isolates were tested for antimicrobial susceptibility by the disk diffusion technique according to the clinical and laboratory standard institute guidelines on mulller Hinten Agar. In all, 37 staphylococcus strains were isolated from the 50 clinical specimen. The details of these isolates comprising S. aureus (22), S. epidermidis (9), S. saprophyticus (6). Staphylococci strains recorded high level of resistance to chloramphenicol (36.4%), rifampicin (22.7%). The isolates were sensitive highly to levofloxacin (81.8%), gentamycin (68.2%) ciprofloxacin (22.7%).
TABLE OF CONTENTS
Title page i
Certification ii
Dedication iii
Acknowledgments iv
Table of Contents v
List of Tables viii
Abstract ix
CHAPTER 1: INTRODUCTION
1.1 Background of Study 1
1.2 Aim of the Study 4
1.2.1 Specific objectives 4
1.3 Significance of the Study 5
CHAP I ER TWO: LITERATURE REVIEW
2.1 Staphylococcus aureus 6
2.1.1 Laboratory Diagnostics 6
2.1.2 Cell Wall 6
2.1.3 Scientific classification 7
2.1.4 Diseases Caused by Staphylococcus aureus 8
2.1.5 Virulence Factors 9
2.1.6 Pathogenesis Staphylococcus aureus 9
2.2 Methicillin resistant Staphylococcus aureus 10
2.2.1 Methicillin Resistance 10
2.2.2 Community-Acquired Methicillin-Resistant Staphylococcus aureus 11
2.3 Prevalence of ethic ileus-resistant Staphylococcus aureus 12
2.4 Impact of metiiicillin-resistant Staphylococcus aureus infection 13
2.5 Control of methicillin-resistant staphylococcus aureus in health care facilities14
2.5.1 Screening of Patients 14
2.5.2 Screening of Staff 15
2.5.3 Isolation and Barrier Nursing 15
2.5.4 Hand Hygiene 16
2.5.5 Environmental Cleaning 16
2.6 Coagulase-negative Staphylococci (CONS) 17
CHAPTER THREE: MATERIALS AND METHOD
3.1 Study area 18
3.2 population study 18
3.3 Collection of samples 18
3.4 Sterilization of materials 19
3.5 Materials and media used 19
3.6 Media preparation 19
3.7 Inoculation and isolation 20
3.8 Purification of isolates 20
3.9 Identification of the bacterial isolates 20
3.10 Isolation of different strains of staphylococcus 20
3.11 Identification Test of Isolates 21
3.12 Gram Staining 21
3.13 Biochemical Reaction Motility Test 21
3.13.1 Catalase test 22
3.13.2 Coagulase test 22
3.13.3 DNase test 22
3.14 Antibiotic Susceptibility Tests of Isolates 23
CHAPTER FOUR: RESULT AND DISCUSSION
4.1 Results 24
4.2 Discussion 32
CHAPTER 5: CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion 35
5.2 Recommendations 35
REFERENCES 36
APPENDIXES
LIST OF TABLES
Table 1: Identification and characterize of Different strains of staphylococcus
Isolates 25
Table 2a: Staphylococcus strains isolated from nasal mucosa (Nose) and skin of
healthy sU.A.U. 26
Table 2b Distribution of Staphylococcus strains isolated from nasal mucosa
(Noise) and skin of healthy students in M.O.U.A.U 26
Table 3 Distribution of different staphylococcus strains isolated 27
Table 4 Antibiotic susceptibility of different staphylococcus strains isolates 28
Table 5a The number and percentage of staphylococcus strains resistance to
Antibiotics 29
Table 5b The number and percentage of staphylococcus strains sensitive to
Antibiotics 30
Table 5c The number and percentage of staphylococcus strains
intermediate to antibiotics 31
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND OF STUDY
The Staphylococcus. consisting of 45 species, is a genus of Gram-positive cocci in grape-like clusters that are non-motile and catalase positive with ability to grow in a variety of conditions aerobically, and anaerobically, in the presence of a high concentration of salt and at temperatures ranging from 18°C to 40°C (Murray el al., 2009). Staphylococcus aureus has the ability., to coagulate blood using the coagulase enzyme and on the basis of this can be distinguished from most other coagulase-negative staphylococcal species (CoSN'S) such as S.epidermidis. S. saprophyticus. S. haemolytiicus, S. hominis and S. lugdimensis (Salgado et al., 2003). Staphylococci are ubiquitous. All persons have coagulase-negative staphylococci on their skin, and transient colonization of moist skin folds with S. aureus is common (Murray et al., 2000'). S. aureus is widely considered a major factor of nosocomial infections ranging from minor skin infections, osteomyelitis and endocarditis, to more serious INFECTION, including fatal neerotizing pneumonia.*Although these infections were historically treatable , beginning in the 1980s. methicillin resistant S. aureus (MRSA) strains have spread rapidly in susceptible hospitalized patients, dramatically changing the therapy available for preventing, and treating staphylococcal infections (Enright et al., 2002).
Staphylococci, particularly Staphylococcus aureus, S. epidermidis, S. saprophyticus. S. haeoulvlicus. S. hominis. and S . lugdimensis are medically important pathogens which cause nosocomial and community infections (Scshadri and Scthuraman. 2016). Staphylococci are classified into coagulase-positive staphylococci known as X. aureus and eoagulase-negative staphylococci (CoXS) such as S. epidermidis. S. saprophyticus, S. haemo/ylicus. S. hominis and another 49 species (Schmidt et al.. 2015). Most strains of these bacteria have developed methicillin resistance and arc therefore called methicillin-resistant S. aureus (MRSA) and methicillin resistant coagulase negative staphylococci (MR-CoNS), which constitute a major health problem. More recently, the number of reports of community-acquired methicillin resistant .S.. aureus (CA-MRSA) has been rapidly increasing. However, infections caused by methicillin resistant coagulase negative staphylococci in the community have not been reported, but the gene transfer from these bacteria to methicillin-resistant S. aureus has been identified (Otto, 2013).
Although methicillin resistant S. aureus infections were relatively uncommon among health) individuals in the community, a dramatic change was observed in 2003 when new strains of methicillin resistant S. aureus were reported to be responsible for outbreaks of community- acquired cutaneous infections and severe pneumonia (Marcinak and T’rank, 2003). Methicillin resistant .S. aureus infections present a challenge to infection control and treatment strategies, resulting in increased morbidity, mortality, and length of hospitalization and health care costs (Kim et al., 2014).
Methicillin-resistant Staphylococcus aureus (MRSA) is a type of staphyloccocal bacteria that is resistant to beta-lactams. These antibiotics include methicillin and other more commonly used antibiotics such as oxacillin, penicillin and amoxicillin. Methicillin resistant S. aureus infections in the community arc mainly skin infections. The most severe form of methicillin resistant .S. aureus infections occur among patients in hospitals. Three out of ten people are colonized in the nose with Staphylococcus aureus and about 2% are colonized with methicillin resistant S. aureus (Grundmann et al., 2006). Methicillin resistant S. aureus was first described in 196land since then it has become an important human pathogen (Tenover et al.. 2001).
As a group, the Coagulase Negative Staphylococcus aureus are among the most frequently- isolated bacteria in the clinical microbiology laboratory. They are becoming increasingly important as causative agents of hospital-acquired bactcraemia, with the increasing use of
prosthetic devices and other invasive technologies in medical institutions (Von-Kiff et al.. 2002). Furthermore. Coagulasc Negative Staphylococcus aureus are nosocomial pathogens associated with multiple antimicrobial-resistance mechanisms including, in particular, methicillin resistance (1 lanbcrger et al., 2001). Therefore, the full and accurate identification of Coagulase Negative Staphylococcus aureus species, which is still difficult in most clinical laboratories, is of diagnostic value, and of clinical and epidemiological importance (Dc Paulis et al., 2003).
The Coagulase Negative Staphylococcus aureus have been implicated as the causative agents in urinary tract disease, pneumonia, endophthalmitis, surgical wound infections, breast abscess (Moa/zex. 2007), osteomyelitis, native valve endocarditis (Marculcseu et al, 2006). periodontitis, chronic rhinosinusitis. and otitis media (Post el al, 2004). Of particular note, is the propensity of some Coagulase Negative Staphylococcus aureus to form a protective bio film which interferes with phagocytosis and efficacy of antimicrobial peptides (Oliveira and Cerca, 2013), more importantly, Coagulase Negative Staphylococcus aureus often serve as reservoirs of antimicrobial resistance determinants; resistance to penicillin approaches 90 to 95 percent, while resistance to methicillin and semisynthetic penicillins has been observed in more than 80 percent of Coagulase Negative Staphylococcus aureus isolates (I)ickema et al., 2001). They are also often resistant to multiple classes of antibiotics in addition to fi lactams. Patients at particular risk for Coagulase Negative Staphylococcus aureus infections include those with prosthetic devices, pacemakers, intravascular catheters, and immuno compromised status (Murray et al, 2009).
Staphylococci, particularly staphylococcus aureus, S. epidermidis, S. saproplyticus, S. haemolyticus, S. hominis, and S. ingdumensis are medically important pathogens which cause nosocomial infections (Seshadri and Sethuraman, 2016).
More recently, the number of reports of community-acquired methicillin resistant S. areus (CA-MRSA) has been rapidly increasing. However, infection causes by methicillin resistant coagulase negative staphylococci in the community have not been reported, but the gene transfer S. aureus has been identified (WHO, 2013).
Methicillin staphylococcal infections were relatively uncommon among healthy individuals in the community, a dramatic change was observed in 2003 when new strains of methicillin resistant S. aureus were reported to be responsible for outbreaks of community acquired cutaneous infections and severe pneumonia (Marcinak and Frank, 2003).
Methicillin resistant staphylococcal infectious present a challenge to infection control and treatment strategies resulting in increased morbidity, mortality and length of hospitalization and health care cost (Kim et al., 2014). Methicillin-resistant staphylococcus aureus (MRSA) is a type of staphylococcal bacteria that is resistant to beta-lactamis.
1.2 AIM OF THE STUDY
The aim of this study is to determine the prevalence and antibio gram of different strains of staphylococci species from apparently healthy students of tertiary institutions in Abia State.
1.2.1 Specific objectives
The specific objectives of the study include the following:
i. To isolate various strains of staphylococcus aureus from students under study.
ii. To identify the antibiotic susceptibility profile of staphylococcus isolates like S. aureus, S. epidermidis and S. saprophyticus.
1.3 SIGNIFICANCE OF THE STUDY
Coagulase negative staphylococci (S. aureus) are nosocomioil pathogens associated with multiple antimicrobial resistance mechanisms including in particular methicillin resistance (Hanberger et al., 2001). Therefore, full and accurate identification of coagulase negative staphylococci species, which is still difficult in most clinical laboratories is of diagnostic value and it is also a clinical and epidemiological importance (Depaulis et al., 2013).
The coagulase negative Staphylococci aureus have been implicated as the causative agents in urinary tract disease, pneumonia, endophthalmitis, surgical wound infection, breast abscess (Moazzez, 2017), oslemyelitis, native valve endocarditis (Marculescu et al., 2006), periodontitis, chronic rhinosinusites and otitis media (Post et al., 2004). Of particular note is the propensity of some coagulase negative staphylococcus aurues to form a protective biofilm which interferes with phagocytisis and efficacy of antimicrobial peptidis (Oliveira and Cerca, 2013).
More importantly, coagulase negative Staphylococcus aureus often serve as reservoirs of antimicrobial resistance determinants, resistant to penicillin approaches 9- to 95 percent, while resistance to methicillin and semisynthetic penicillin has been observed in more than 80 percent of coagulase negative staphylococcus aureus isolates (Diekema et al., 2001), they are also often resistant to multiple classes of antibiotics in addition to B-lactens.
Finally, the detection of coagulase negative staphylococci is a very expedient diagnostic component for multiple drug resistant coises (Diekema et al., 2001).
Patients at particular risk for coagulase negative staphylococcus aureus infections include those with prosthetic devices, pacemakers intravascular catheters and immune-compromised status (Murray et al., 2009).
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