# I. Introduction oagulase-negative staphylococci (CoNS) are part of normal commensals of the skin, anterior nares, and ear canals of humans [1]. Because of their relatively low virulence, they have long been considered as nonpathogenetic, and were rarely reported to cause severe infections. However, as a result of the combination of increased use of intravascular devices and an increase in the number of hospitalised immunocompromised patients, CoNS have emerged and are increasingly recognised as a major agents of clinically significant infection of the bloodstream and other sites [2,3,4,5,6,7,8]. Given the frequency with which multiple antimicrobial resistance is encountered, treatment of CoNS infections can be challenging and oxazolidinone: Line zolid has been considered the drug of choice for the management of infections caused by gram-positive organisms, including resistant organisms, such as methicillin-resistant Staphylococcus aureus, methicillinresistant coagulase-negative staphylococci (MRCoNS), vancomycin-resistant enterococci, and multidrugresistant Streptococcus pneumonia [9,10,11,12,13,14,15]. However, widespread use of linezolid recently has led to the emergence of CoNS isolates with decreased susceptibility to these agents further limiting therapeutic options for treatment of infections caused by these organisms [16,17,18]. In Nigeria, to date, Linezolid-Resistant Coagulase Negative Staphylococcus (LRCoNS) have not been reported, although there are no indications of the use of linezolid within the study area, it is recognized as one of the few drugs that have been reported to be effective in the treatment of infections caused by MRCoNS. In the current study, we determined nasal carriage rate of CoNS and antimicrobial resistance profile of these coagulase-negative staphylococci isolates with linezolid resistance that were recovered from apparently healthy undergraduate students in Niger Delta University. This study will however serve as a reference point data for nasal carriage rate and Linezolid antimicrobial profile of CoNS for the region. # II. Materials and Methods # a) Sampling Area The study was carried out in Amassoma, a semi urban settlement in the Niger Delta and is home to the Niger Delta University with a student population of about 20,000. It is located on Latitude 4? 59' 09'' N and longitude 6? 06' 34'' E. Its land area is 2,682Km2 (1,036 sq miles) at an elevation/altitude of 9 metres. It is in an area of high humidity (mean: 300C) and temperature (average: 26.7? C with annual rainfall of about 1777mm. The students sampled in this study were medical and nursing students of the university. They are of age: (range: 15-39, mean = 22), Sex: (Males: 124; Females: 276) and have stayed a period of 1 year minimum in the University # b) Sampling Anterior nares swabs were collected in accord to protocols described by Rongpharpi et al [19]. A total of 400 nasal swabs were collected from anterior nares of apparently healthy subjects aseptically using a sterile swab sticks (Copan Diagnostics, Corona, CA, USA). Swabs were transported in Amies (Oxoid, England) transport medium to the Medical microbiology laboratory of the College of Health Sciences, Niger Delta University for bacteriological assay. # c) Isolation and Identification In the laboratory, each swab was immediately inoculated onto Mannitol Salt Agar (MSA; Oxoid, England) plates and incubated at 37C for 24 h. The characteristic isolates were aseptically isolated and characterized using established microbiological methods that include colonial morphology, Gram stain characteristics, haemolysin production catalase, coagulase tests as well as DNase production [20]. The various isolates were identified to species level by employing standard microbiological methods [20,21]. Coagulase negative-Staphylococci isolates were confirmed through the use of the Staph identification 25 E (BioMeriux, France). # d) Antimicrobial Susceptibility Testing The antimicrobial susceptibility pattern of all the isolates to Augmentin (30?g), Cefoxitin (30?g), Ciprofloxacin (5?g), Co-trimoxazole (25?g), Erythromycin (15?g), Gentamycin (30?g), Linezolid (30?g), and Tetracycline (30?g) all obtained from Oxoid (England) were determined using modified single disc diffusion technique in accordance to the guidelines of Clinical and Laboratory Standards Institute (CLSI, 2012) [22]. Briefly, standardized overnight culture of each isolate (containing approximately 106 cfu/ml) which was equivalent to 0.5 McFarland Standard was used to swab the surface of Mueller Hinton agar plates and excess drained off and dried while the Petri dish lid was in place. The standard antimicrobial discs were aseptically placed at reasonable equidistance on the inoculated plates and allowed to stand for I hr. The plates (prepared in duplicates) were then incubated at 37 0 C for 18-24 h. The diameter of the zone of inhibition produced by each antimicrobial disc was measured with a ruler in millimeters. Breakpoints and interpretative for susceptibility/resistance was based on the CSLI criteria [22]. We used the agar dilution method to further confirm the Linezolid MIC's (lowest concentration at which growth was inhibited) values of the linezolidnonsusceptible CoNS isolates. The MIC (?g/mL) interpretative standard for linezolid were those suggested by CLSI [22], (respectively: ? 4 susceptible, ? 8 resistant). The procedure was performed in duplicate on separate occasions, and the means of the duplicates were used. Staphylococcus aureus NCTC6571 was used as the quality control in each set of tests. # e) Statistical analysis SPSS for Windows (version 20.0; SPSS) software was used for the analysis. Frequency distribution, mean, harmonic mean, standard deviation, analysis of variance (ANOVA) were determined. Categorical variables were compared by using Pearson's chi-squared test (?2) or Fisher's exact probability tests. P-values were calculated and P ?0.05 was considered statistically significant # III. Results As depicted in Table 1, 227(56.8%) of the 400 studied subjects yielded Staphylococci growths. The overall carriage rates of Coagulase Negative Staphylococci was 136(34.03%). As shown in Figure 1, we identified and confirmed that the 136 CoNS strains belong to 7 species including S. epidermidis 50(36.76%) which is the most prevalent. This is followed by S. haemolyticus 41(30.15%), S. saprophyticus 13(9.56%), S. hominis 10(7.35%), S. cohnii 8(5.88%), while Staphylococcus lugdunensis and S. xylosus were 7(5.15%) each. Figure 2, shows the antimicrobial susceptibility profile of the isolates. Overall 112(82.4%) of the 136 CoNS isolates showed resistance to Erythromycin, while resistance were 108 (79.4) The prevalence of multiple antibiotic resistance (MAR) of the isolates was investigated. One hundred and twelve (82.35%) of the isolates showed multiple resistance in varying degrees. Twenty-three (20.54%), 18 (16.07%), 26(23.21%), 22(19.64%), and 10 (8.93%) were resistant to 3, 4, 5, 6, and 7 antibiotics among the isolated strains respectively. Thirteen (11.61%) of the isolates were resistant to all the 8 antibiotics tested (Figure 3). # IV. Discussion We conducted this study in order to determine the nasal carriage rate and antimicrobial resistance profile of CoNS strains isolated from the anterior nares of apparently healthy students of a tertiary institution in Wilberforce Island, Amassoma. The institution is situated in a semi urban area in Bayelsa-state in the Niger Delta. The result obtained from the present study will serve as a reference data for CoNS carriage rate. In addition, the study also gives an understanding into the patterns of antimicrobial resistance profile of these isolates in the locality. The study revealed that 136 out of the 400 subjects examined were positive for CoNS in their anterior nares, indicating the nasal carriage rate of 34.03%. Earlier, report indicates the nasal carriage rate of CoNS to vary from 13% to 56% in different populations [13,23,24,25]. Though we observed lower figure in the present study, our findings is in comparison with the carriage rates documented by Morgenstern et al. [26] and Lebeaux et al. [27] in Portugal and France respectively. Contrast with our findings, higher nasal carriage rates have however been reported by Koziol-Montewka et al., 2006 in Poland (55.8%) [28], Campeotto et al. 2004 in Brazil (66.1%) [29], Akhtar 2010 inPakistan (73.3%) [30] and Abadi et al. 2015 in Iran (77.7%) [31]. Shibabaw et al. [32] attributed these differences to various microbiological methods (sampling techniques to culture media) employed, the local infection control standards and the local prevalence rate. Aside from these, it has been suggested that carrier rates might also be influenced by poor personal hygiene, poor environmental sanitation [32] and age-related dynamics of the study participants [1]. The low recovery rate of CoNS observed in the present study might be due to the fact that our subjects being medical and nursing students may have been involved in good hygiene practices with hand washing inclusive. On the other hand, as documented by Onasoga, et al., 2015 [33], they may have also been involved in self-medication or predisposed to the misuse of antibiotics. The results showed that seven species of CoNS were identified. The most common species isolated was S. epidermidis 50(36.76%). The similar results were recorded in many studies [34]. Various studies have indicated most CoNS isolates obtained in the present study as responsible for infections that are of endogenous origin particularly among immunocompromised and individuals that are hospitalized [35,36,37,38,39,40]. Over the years, studies have shown that antimicrobial therapy causes marked symptom improvement and shortens the duration of illness associated with Staphylococci infections. Before now, various types of antimicrobial agents have been efficacious in the management of Staphylococci infections, but options for treatment of these diseases are becoming restricted due to the appearance of multidrug-resistant strains of CoNS. There has been global concern about the emergence of antimicrobial resistance in common pathogens of community as well as nosocomial infections and CoNS have demonstrated a pattern of progressively increasing resistance to antibiotics worldwide [41,42,43,44,45,46,47,48]. The results obtained from the present study indicates that 112(82.35%) of the 136 isolates from this environment are multiply resistant to antibiotics, (Figure 3). In comparison, the pattern of multidrug resistance demonstrated here has been described among CoNS isolates in different part of the world which includes Switzerland [26], India [49], Iran [31,34], China [44] , USA [50] ,France [27], Pakistan [30], Italy [51] and Poland [28]. The antibiotic susceptibility pattern of the isolates shows that Gentamycin was the most effective among the CoNS, followed by augmentin, in that order (Figure 2). When compared with existing report, the 22.8% resistance of the CoNS isolates to Gentamycin in this finding corroborates the report of Ma et al. [48] and is different with report of Al-Muhanna et al. [34] that 32% of CoNS isolates were resistant to Gentamycin, while Roopa and Biradar [49] and Zhanel et al. [52] reported 0.0% and 78.8% resistance of these pathogens to Gentamycin respectively. So gentamycin is the only drug in this study that is proven to be effective for CoNS. One of the reason for this high susceptibility seen in this study may be that gentamycin appears to be infrequently used as it administered by injection, a dosage form which is far less amenable to selfmedication than orally administered antibiotics in this locality [53]. On the other hand, the high susceptibility to augmentin observed in this study is in sharp contrast to existing reports (31.6% versus 70%; P < 0.0001) by Abdalla et al. [54] and Akinkunmi and Lamikanra [55] that 70% and 62.4% resistance of CoNS to augumentin respectively. Nonetheless, the present findings corroborates the report of Roopa and Biradar [49]. One of the reason that could be adduced to low resistance observed in this study may be that augumentin, though an orally administered antibiotics, seems to be rarely abused by individuals in the locality because of its exorbitant price (about 10USD) for a packet in a locality where people live below 1USD per day. The antimicrobial resistance profile of CoNS isolated in this study indicated that 58.8% of the isolates were resistant to Cefoxitin [MR-CoNS]. This result is higher than earlier report [49,55], and, lower than report made by Al-Muhanna et al., [34], Maet al. [48] and Koksal et al [56]. However, it is similar to the report made by Lebeaux et al. [27] among the organisms isolated in their respective studies. Reports have documented that resistance to Cefoxitin by disc diffusion can be used for the detection of MRSA strains in routine testing [57] because Cefoxitin is regarded as a potential inducer of the system that regulates mecA gene [58]. For this reason, the resistant of our isolates which were found to be resistant to Cefoxitin are considered resistant to methicillin (58.8% MR-CoNS). During the susceptibility test in the present study, one of our limitations was excluding Vancomycin, the drug considered efficacious for MRSA and MRCoNS, from the test because of unavailability of its commercial disc. Nonetheless, Delorme et al. [59] reported the exclusion of vancomycin from their study because vancomycin may produce erratic results in disc diffusion susceptibility test [59]. However, even with the absence of vancomycin susceptibility test, the result of this study can be compared with the findings of several outcomes including [60,61,62,63] which established that linezolid is a drug that is as effective as vancomycin. Both antibiotics do not just have similar failure and success rates but adverse effects as well [61,64]. Approximately, 69.1% of the CoNS isolates showed high resistance to trimethoprim/sulfamethoxazole in this study. This is similar to what has been reported by Koksal et al. [56] and Akinkunmi and Lamikanra [55] in Turkey and Ile-Ife, Nigeria respectively and many other researchers, a finding correlated to that by Ma et al [48] and Abadi et al. [31]. This could be due to the fact that this drug is very commonly available in our setting and is also indiscriminately used for prophylaxis by individuals with symptoms of Upper Respiratory Tract infections (URTI) and Urinary Tract Infections (UTI). The study by Paul et al. [65] showed zero resistance to trimethoprim/sulfamethoxazole to Staphylococcus aureus in Nigeria in 1985, while Gu et al. [10] showed 29.4% trimethoprim/sulfamethoxazole in Greece. This is worthy of mention and comparison. It shows that trimethoprim/sulfamethoxazole resistance has increased prodigiously over the prevailing years. The majority of our CoNS isolates were highly resistant to erythromycin (82.4%), and the high rate (79.4%) of resistant to tetracycline and Ciprofloxacin (55.1%), found in this study is worrisome considering the ability of these organisms to spread easily by direct or indirect person-to-person contact with resultant therapeutic complications and considering that ciprofloxacin has been identified as the drug being the most efficaciousanti-infective drug in Nigeria [43,66]. Combating the increase in mortality and morbidity due to therapeutic failures in the treatment of multidrug resistant Staphylococci infections, particularly those that are methicillin and vancomycin resistances, gave rise to the need for newer efficacious therapeutic options leads to the discovery and approval of oxazolidinone antibiotic: linezolid by FDA in 2000 as an attractive alternative to vancomycin and MRSA [60,67]. It is tragic that barely one year of its introduction into treatment regime for multidrug resistant Gram-positive organisms, the first resistant among Enterococcus faecium, was reported [68] and Tsiodras et al. [69] reported the first Linezolid resistant Staphylococcus aureus in a US patient. Since then, linezolid-resistant S. aureus and CoNS have been detected in separate cases and outbreaks worldwide [10,70,71]. Currently, 48.5% of CoNS isolated from the present study were found to be linezolid resistant. Making this finding one of the highest resistance rate recovered among CoNS isolates in Nigeria and amongst those recorded globally. This study revealed that S. epidermidis, S. haemolyticus, S. cohnii, S. saprophyticus, S. hominisisolates, were resistant to linezolid in 52%, 50%, 48.78%, 46.15%, and 40% respectively, while S. lugdunensisand S. xylosus showed 42.86% resistance to linezolid each (Table 2). To confirm this resistivity, we decided to carryout Minimum Inhibitory Concentration tests on these isolates as suggested by CLSI 2012 [22], and the outcome showed that all our linezolid resistant isolates had MICs >256µg/mL. Previous studies have shown various resistance profiles of CoNS to linezolid. For example, Morgenstern et al. [26] in Switzerland and [44] in China reported 0% resistance to linezolid respectively. However, globally, surveillance studies report <1% of CoNSas linezolid resistant. But, a study conducted by Potoski et al. [72] in the USA, observed Linezolid resistance in about 4.0% of MRCoNS isolates. Another study conducted in USA by Helio and colleagues reported LRCoNS in 0.1% [50]. Similarly, incidence of 0% was reported by Al-Muhanna et al. [34] from Iraq. Ugwuet al. [66] reported 0% LRCoNS in Southern Nigeria. The high incidence of linezolid resistance in the organisms isolated in this study is not expected since this antibiotic is not broadly used within the study environment, this is worrisome and is worthy of note. Particularly that linezolid is not routinely prescribed and administered in our locality. More so that the drug is very difficult, if available in our market, in other words, its availability for misuse or selfadministration as reported among other antibiotics is not anticipated [73]. So, this high resistance recorded must be of concern to practitioners and public health, more so, that these organisms live in association with other organisms in their ecological niche and can disseminate these resistances to other organisms within the environment [73].This collaborates reports made by Garcia et al. [74] that horizontal transmission of linezolid resistance could pose a serious threat, because the cfrgene can also be transmitted between species, such as from S. epidermidis, which although not pathogenic, could become a reservoir for resistance genes and that this mode of transmission becomes more difficult to prevent and stop than those of nosocomial spread that are usually controlled with standard measures, such as isolation, barrier precautions, and antibiotic restriction On the other hand, these organisms and their antimicrobial resistancehave been documented to be associated with opportunistic infections and can be transferred from these individuals to the patients, hospital environments and the community [41,75,76] making it a life-threatening organism which may lead to increase mortality and morbidity, particularly among colonised individuals, immunocompromised and HIV patients.Staphylococcal resistance to linezolid (LZD) is said to be mediated through ribosomal mutations (23S rRNA or ribosomal proteins L3 and L4) or through methylation of 23S rRNA by the horizontally transferred chloramphenicol-florfenicol resistance (Cfr)plasmidborne ribosomal methyltransferase that catalyzes methylation of A2503 in the 23S rRNA gene of the large 50S ribosomal subunit, conferring resistance to chloramphenicol, florfenicol, and clindamycin [9,77,78,79,80,81,82]. The first cfr-mediated, linezolid-resistant clinical isolate of MRSA was reported in 2007 by Tohet al. [83]. More recently, linezolid resistance has been identified due to acquisition of a natural resistance gene, cfr, so the high resistance of the present study CoNS isolates to linezolid might be due to acquisition of resistance to chloramphenicol, as chloramphenicol is one of the antibiotics that are readily available and most abuse, misuse and self-medicated in our locality. However, this assumption would be further investigated. # V. Conclusion The study findings indicate the usefulness of investigation of CoNS colonisation of the nasal mucosa the primary ecological niche for these microorganisms in order to better understand the epidemiology of this phenomenon, but also to develop prevention measures and treatment strategies in case of established infections among predisposed individuals. # VI. Acknowledgements We are grateful to Ogobiri Gloria Tamaraemomoemi, Tiemo, and Pereyan Cynthia for Collection of the samples and the school students for participating in this study. # Volume XVI Issue III Version I ![Figures and Tables](image-2.png "") 23![Figure 2: Antimicrobial susceptibility profile of CoNS isolates. KEY: AMC: Augmentin (30?g), CEF: Cefoxitin (30?g), CIP: Ciprofloxacin (5?g), COT: Co-trimoxazole (25?g), E: Erythromycin (15?g), CN: Gentamycin (30?g), LZD: Linezolid (30?g), and TE: Tetracycline (30?g)](image-3.png "Figure 2 :Figure 3 :") 1Staphylococci colonising anterior naresAgeMaleFemaleNo (%) Isolate15-194610(7.35)20-24304979(58.09)25-29241337(27.21)30-34437(5.15)35-39303(2.21)Total6571136(100)41Volume XVI Issue III Version I 2S. xylosus(n=7)KEY: AMC: Augmentin (30?g), CEF: Cefoxitin (30?g), CIP: Ciprofloxacin (5?g), COT: Co-trimoxazole (25?g), E: Erythromycin (15? g), CN: Gentamycin (30?g), LZD: Linezolid (30?g), and TE: Tetracycline (30?g)Figure 1: © 2 016 Global Journals Inc. (US) Linezolid and Methicillin-Resistant Coagulase Negative Staphylococci from Anterior Nares of Nigerian Tertiary School Students * Coagulasenegative staphylococci KBecker CHeilmann GPeters Clin Microbiol Rev 27 870 2014 * Diversity of SCCmec elements in methicillin-resistant coagulase-negative staphylococci clinical isolates ZYZong CHPeng XJLu PLoS One 6 e20191 2011 * Identification of a variety of Staphylococcus species by matrix-assisted laser desorption ionizationtime of flight mass spectrometry DDubois DLeyssene JPChacornac MKostrzewa POSchmit RTalon RBonnet JDelmas J Clin Microbiol 48 2010 * Risk factors and management of Grampositive bacteraemia CCervera MAlmela JAMartinez-Martinez AMoreno JMMiro Int. J. Antimicrob. Agents 34 2009 Suppl. 4 * Staphylococcus epidermidis -the 'accidental' pathogen MOtto Nat Rev Microbiol 7 2009 * Coagulase-negative staphylococcal infections KLRogers PDFey MERupp Infect Dis Clin North Am 23 1 2009 * ALCasey PALambert ElliottTsjStaphylococci Int J Antimicrob Agents 29 2007 Suppl. 3 * An overview of nosocomial infections, including the role of the microbiology laboratory TGEmory RPGaynes Clin Microbiol Rev 6 1993 * Mechanisms of Linezolid Resistance among Coagulase-Negative Staphylococci Determined by Whole-Genome Sequencing RTewhey BGu TKelesidis CCharlton ABobenchik JHindler NJSchork 10.1128/mBio.00894-14 mBio 2014 3 * The emerging problem of linezolid-resistant Staphylococcus BGu TKelesidis STsiodras JHindler RMHumphries J Antimicrob Chemother 68 2013 * LEADER Program results for 2009: an activity and spectrum analysis of linezolid using 6,414 clinical isolates from 56 medical centers in the United States DJFarrell REMendes JERoss Antimicrob Agents Chemother 55 2011 * Eight-year (2002-2009) summary of the linezolid (Zyvox(R) Annual Appraisal of Potency and Spectrum; ZAAPS) program in European countries JERoss DJFarrell REMendes J Chemother 23 2011 * Linezolid-resistant ST36 methicillin-resistant Staphylococcus aureus associated with prolonged linezolid treatment in two paediatric cystic fibrosis patients RLHill AMKearns JNash J Antimicrob Chemother 65 2010 * Sequential Linezolid-Resistant Staphylococcus epidermidis Isolates with G2576T Mutation v THong XLi JWang CSloan CCicogna J Clin Microbiol 45 10 2007 * Oxazolidinone antibiotics DJDiekema RNJones Lancet 358 2001 * Clinical outbreak of linezolid-resistant Staphylococcus aureus in an intensive care unit MSanchez Garcia DeLa Torre MAMorales G JAMA 303 2010 * Assessment of linezolid resistance mechanisms among Staphylococcus epidermidis causing bacteraemia in Rome, Italy REMendes LMDeshpande DJFarrell J Antimicrob Chemother 65 2010 * Study of developed resistance due to antibiotic treatment of coagulasenegative staphylococci ATegnell KGrabowska AJacobsson MAndersson JGiesecke LOhman Microb Drug Resist 9 2003 * The prevalence of nasal carriage of Staphylococcus aureus among healthcare workers at a tertiary care hospital in Assamwith special reference to MRSA SRRongpharpi NKHazarika HKalita J Clin. Diagn Res 7 2 2013 * District laboratory practice in tropical countries Part 2: Edingburgh building MCheesbrough 2002 Cambridge University Press UK. * Manual for the identification of medical Bacteria STCowan KJSteel Barrow GI. Feltham RKA 2004 Cambridge University Press 3rd edition * Performance standards for antimicrobial susceptibility testing. Eighteenth Information Supplement 2012 28 Clinical and Laboratory Standards Institute (CLSI * Molecular epidemiology of coagulasenegative Staphylococcus carriage in neonates admitted to an intensive care unit in Brazil YMTernes JLamaro-Cardoso McpAndré PessoaVpJr MasVieira RMinamisava ALAndrade AKipnis BMC Infectious Diseases 13 572 2013 * Colonization pattern of coagulasenegative staphylococci in preterm neonates and the relation to bacteremia MBjorkqvist MLiljedahl JZimmermann JSchollin BSoderquist Eur J Clin Microbiol Infect Dis 29 9 2010 * Extreme genetic diversity of methicillin-resistant Staphylococcus epidermidis strains disseminated among healthy Japanese children TZJamaluddin KKuwahara-Arai KHisata MTerasawa LCui TBaba CSotozono SKinoshita TIto KHiramatsu J Clin Microbiol 46 11 2008 * Antibiotic Resistance of Commensal Staphylococcus aureus and Coagulase-Negative Staphylococci in an International Cohort of Surgeons: A Prospective Point-Prevalence Study MMorgenstern CErichsen SHackl JMily MMilitz JFriederichs 10.1371/journal.pone.0148437 PLoS ONE 11 2 e0148437 2016 * Evolution of Nasal Carriage of Methicillin-Resistant Coagulase-Negative Staphylococci in a Remote Population DLebeaux FBarbier CAngebault LBenmahdi ERuppé BenjaminFelix B Antimicrob Agents and Chemother 56 1 2012 * The investigation of Staphylococcus aureus and coagulasenegative staphylococci nasal carriage among patients undergoing haemodialysis MKoziol-Montewka ASzczepanik IBaranowicz LJo´z´wiak AKsia ? Z?ek DKaczor Microbiol Res 161 2006 * A routine prospective survey process to detect nosocomial bacterial colonization in a neonatal unit: risk factors for acquisition FCampeotto FGarnier NKalach PSoulaines CDupont JRaymond Arch Pediatr 11 11 2004 * Staphylococcal Nasal Carriage of Health Care Workers NAkhtar J Coll Physicians Surg Pak 20 7 2010 * Molecular Characteristics of Nasal Carriage Methicillin-Resistant Coagulase Negative Staphylococci in School Students MimAbadi RMoniri AKhorshidi APiroozmand SgaMousavi KDastehgoli HMGhazikalaye Jundishapur J Microbiol 8 6 e18591 2015 * Antimicrobial susceptibility pattern of nasal Staphylococcus aureus among dessie referral hospital health care workers, dessie, Northeast Ethiopia AShibabaw TAbebe AMihret Int J. Infect Dis 25 2014 * Pattern and management of sexually transmitted infections (STIs) among undergraduates attending university health care centre in Bayelsa State OAOnasoga AAbdu BNAnabui VFHanson Nigeria. Int STD Res Rev 3 3 2015 * Characterization of coagulase-negative, oxacillin resistant staphylococci from patients undergoing catheter related infections ASAl-Muhanna SAAl-Hilu MAAlzuhairi Eur J Exp Biol 4 3 2014 * Health care workers causing large nosocomial outbreaks: a systematic review LDanzmann PGastmeier FSchwab RPVonberg 10.1186/1471-2334-13-98 23432927 PMC3599984 BMC Infect Dis 13 98 2013 * Inferring a population structure for Staphylococcus epidermidis from multilocus sequence typing data MMiragaia JCThomas ICouto MCEnright HDe Lencastre J Bacteriol 189 6 2007 * Coagulase-Negative Staphylococci KBecker CHeilmann GPeters Clin Microbiol Rev 27 4 2014 * Comparison of genotypic and phenotypic methods for species-level identification of clinical isolates of coagulase-negative staphylococci EHeikens AFleer APaauw AFlorijn ACFluit J Clin Microbiol 43 5 2005 * Isolation of methicillin-resistant coagulase-negative staphylococci from patients undergoing continuous ambulatory peritoneal dialysis (CAPD) and comparison of different molecular techniques for discriminating isolates of Staphylococcus epidermidis EMDe Mattos LATeixeira VMAlves CARezenda E Resende MVDa Silva Coimbra MCDa Silva-Carvalho BTFerreira-Carvalho AMFigueiredo Diagn Microbiol Infect Dis 45 1 2003 * Occurrence and antibiogram profile of Staphylococcus aureus isolated from some hospital environment in Zaria CHammuel MOIdoko HHMigap NAmbrose Nigeria. Afr J Microbiol Res 9 19 2015 * Prevalence and antibiogram pattern of some nosocomial pathogens isolated from hospital environment in Zaria CHammuel DEJatau CmzWhong Nigeria. Aceh Int. J. Sci. Technol 3 3 2014 * Epidemiology of methicillinresistant Staphylococcus aureus among hospitalized patients and apparently healthy individuals in Ekiti and Ondo States EOBabafemi OMDavid AOOluduro OFamurewa Nigeria. J Pharm Biomed Sci 4 11 2014 * Antibiotic resistance pattern of methicillinresistance and coagulase-negative Staphylococcus isolates among hospitalized patients at a tertiary hospital in Gansu, North-western China LWei RWu FZou GLiu LWu QWei JLi LLei HDuo Afr. J. Microbiol. Res 8 1 2014 * Knowledge and use of disinfection policy in some government hospitals in South-East ANOli JNNweke MCUgw LOAnagu AHOli EsimoneCo Nigeria. Bri J. Med Medical Res 3 4 2013 * Emergence of linezolid-resistant Staphylococcus aureus after prolonged treatment of cystic fibrosis patients in cleveland AEndimiani MBlackford ECDasenbrook MDReed SBajaksouszian AMHujer Antimicrob. Agents Chemother 2011 * Antibiotic resistance and molecular epidemiology of Staphylococcus aureus in Nigeria AOShittu KOkon SAdesida OOyedara WWitte BStrommenger BMC Microbiol 11 92 2011 * Antibiotic susceptibility of coagulase-negative staphylococci (CoNS): emergence of teicoplaninnon-susceptible CoNS strains with inducible resistance to vancomycin XXMa EHWang YLiu EJLuo J Med Microbiol 60 2011 * Incidence and Speciation of Coagulase Negative Staphylococcus Isolates from Clinically Relevant Specimens with their Antibiotic Susceptibility Patterns CRoopa SBiradar Int. J. Curr. Microbiol. App. Sci 2015 9 * Antimicrobial Activity of Ceftaroline Tested against Staphylococci with Reduced Susceptibility to Linezolid, Daptomycin, or Vancomycin from U.S. Hospitals SHelio RobertKSader RonaldNFlamm Jones Antimicrob Agents and Chemother 57 7 2008 to 2011. 2013 * DNA methylase modifications and other linezolid resistance mutations in coagulase-negative staphylococci in Italy DBongiorno FCampanile GMongelli MTBaldi RProvenzani SReali J Antimicrob Chemother 65 2010 * Antimicrobial susceptibility of 22746 pathogens from Canadian hospitals: results of the CANWARD GGZhanel HJAdam MRBaxter JFuller KANichol AJDenisuik PLagacé-Wiens AWalkty JAKarlowsky FSchweizer DJHoban * 10.1093/jac/dkt022 J. Antimicrob. Chemother 68 2013 Suppl * Prevalence of communityassociated multiresistant Staphylococcus aureus among healthy women in Abuja AOnanuga AROyi BOOlayinkayinka JAOnaolapo Nigeria. Afr. J. Biotech 4 2005 * Antibiotics Sensitivity Profile Towards Staphylococcus hominis in Assir Region of Saudi Arabia NMAbdalla WOHaimour AAOsman MASarhan HAMusaa J. Sci. Res 5 1 2013 * Species Distribution and Antibiotic Resistance in Coagulase-negative Staphylococci Colonizing the Gastrointestinal Tract of Children in Ile-Ife, Nigeria EOAkinkunmi ALamikanra Trop J Pharm Res 9 1 2010 * Antibiotic resistance patterns of coagulase-negative staphylococcus strains isolated from blood cultures of septicemic patients in Turkey FKoksal HYasar MSamasti Microbiol Res 164 2009 * (CLSI) performance standards for antimicrobial susceptibility testing. Twenty-fourth Information Supplement 2014 34 Clinical and Laboratory Standards Institute * Correlation of cefoxitin disc diffusion test and oxacillin disc diffusion test for detecting mecA mediated oxacillin resistant Staphylococcusaureus NSMadhusudhan SDeepa DNShoba J. Pharm Biomed Sci 10 2 2011 * Epidemiology and susceptibilities of methicillinresistant Staphylococcus aureus in Northeastern Ohio TDelorme SRose JSenita CCallahan PNasr The Am J Clin Pathol 132 5 2009 * Antibiotic resistance profiling of Staphylococcus aureus isolated from clinical specimens in a tertiary hospital from 2010 to 2012 ACJuayang GBDe Los Reyes AjgDe La Rama CTGallega 10.1155/2014/898457 Interdiscip Perspect Infect Dis 2014 2014 * Vancomycin versus linezolid in the treatment of methicillin resistant Staphylococcus aureus nosocomial pneumonia: Implications of theZEPHyR trial JMPogue CAlaniz Ann Pharmacother 46 10 2012 * The continuing threat of methicillin resistant Staphylococcus aureuspast, present, future ZKhan SFaisal SHasnain J Sci Res 40 2 2010 * Epidemiology of meticillin-resistant Staphylococcus aureus (MRSA) in Latin America MGuzmán-Blanco CMejía RIsturiz CAlvarez LBavestrello EGotuzzo JLabarca CarlosMLuna ERodríguez-Noriega MjcSalles JZurita CSeas Int J Antimicrob Agents 34 4 2009 * Morbidity and cost burden of methicillinresistant Staphylococcus aureus in early onset ventilator-associated pneumonia AFShorr YPTabak VGupta RSJohannes LZLiu 10.1186/cc4934):1-7 Crit. Care 10 R97 2006 * Antimicrobial sensitivity patterns of hospital and non-hospital strains of Staphylococcus aureus isolated from nasal carriers MOPaul DAAderibigbe CZSule ALamikanra J Hyg (Lond) 89 1982 * Characterization of mannitol-fermenting methicillin-resistant staphylococci isolated from pigs in Nigeria CCUgwu EGomez-Sanz ICAgbo CTorres ChahKf Brazilian Journal of Microbiology 46 3 2015 * Low prevalence of cfr mediated linezolid resistance among methicillin-resistant Staphylococcus aureus in a Spanish Hospital: Case report on linezolid resistance acquired during linezolid therapy JMSierra MCamoez FTubau OGasch MPujol DOI: 10. 1371/journal.pone.0059215 PLoS ONE 8 3 e59215 2013 * First of a new drug class for gram positive infections Anonymous Linzolid DOI: 102165/0004231020011709000001 DrugsTher Perspect 17 9 2001 * Linezolid resistance in a clinical isolate of Staphylococcus aureus STsiodras HSGold GSakoulas Lancet 358 2001 * Incidence, management and outcomes of the first cfr-mediated linezolid-resistant Staphylococcus epidermidis outbreak in a tertiary referral centre in the republic ofIreland CO'connor JPowell CFinnegan AO'gorman SBarrett KLHopkins The J Hosp Infect 90 4 2015 * Resistance to linezolid is mediated by the cfr gene in the first report of an outbreak of linezolid resistant Staphylococcus aureus MGarcia JJuan BElvira Clin Infect Dis 50 6 2010 * Epidemiological Profile of Linezolid-Resistant Coagulase-Negative Staphylococci BAPotoski JAdams LClarke KShutt PKLinden CBaxter AWPasculle BCapitano AYPeleg DSzabo DLPaterson Clin Infect Dis 43 2006 * Linezolid and Methicillin Resistances in S. aureus Isolated from the Anterior Nares of Apparently Healthy Undergraduates of the Niger Delta University AAbdu ALamikanra Br Microbiol Res J 15 6 2016 * Resistance to linezolid is mediated by the cfr gene in the first report of an outbreak of linezolid-resistant Staphylococcus aureus MGarcia JJuan BElvira Clin Infect Dis 50 6 2010 * Coagulase-negative staphylococci: Update on the molecular epidemiology and clinical presentation, with a focus on Staphylococcus epidermidis and Staphylococcus saprophyticus MWiderstrom JWistrom ASjostedt Eur J Clin Microbiol Infect Dis 31 2012 * Antimicrobial resistance: Not community-associated methicillinresistant Staphylococcus aureus (CAMRSA)! A clinician's guide to community MRSA-its evolving antimicrobial resistance and implications for therapy KChua FLaurent GCoombs MLGracyson BPHowden Clin Infect Dis 52 2011 * Investigation of linezolid resistance in Staphylococcus epidermidis: first reported linezolid resistant coagulase negative staphylococcus in Turkey BYalçin MBSelek BBektöre THo?bul MÖzyurt Turk J Med Sci 44 2014 * Emergence of cfr-harbouring coagulasenegative staphylococci among patients receiving linezolid therapy in two hospitals in China XJYang YChen QYang TTQu LLLiu HPWang YSYu J Med Microbiol 62 2013 * Resistance to linezolid caused by modifications at its binding site on the ribosome KSLong BVester Antimicrob Agents Chemother 56 2 2012 * DNA methylase modifications and other linezolid resistance mutations in coagulase-negative staphylococci in Italy DBongiorno FCampanile GMongelli J Antimicrob Chemother 65 2010 * Use of pyrosequencing to identify point mutations in domain V of 23S rRNA genes of linezolid-resistant Staphylococcus aureus and Staphylococcus epidermidis WZhu FCTenover JLimor Eur J Clin Microbiol Infect Dis 26 2007 * A new mechanism for chloramphenicol, florfenicol and clindamycin resistance: methylation of 23S ribosomal RNA at A2503 CKehrenberg SSchwarz LJacobsen LHHansen BVester Mol. Microbiol 57 4 2005 * Acquisition of a natural resistance gene renders a clinical strain of methicillin-resistant Staphylococcus aureus resistant to the synthetic antibiotic linezolid SMToh LXiong CAArias MVVillegas KLolans JQuinn ASMankin Mol Microbiol 64 2007 * SCohnii 5 88 * Antibiotics No (%) CoNS of isolates resistant to antibiotics Total S. epidermidis (n=50) * SHaemolyticus n=41 * SSaprophyticus * SHominis n=10 * SCohnii n=8 * SLugdunensis n=7