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Objective: we investigated previous literatures for documentation of the trend in Sokoto, Nigeria and found none. We deemed it fit to determine the frequency of linezolid resistance mediated by cfr gene among MRSA isolates from Sokoto State-owned hospitals. Methods: Bacterial species identification was carried out with Microgen™ Staph-ID System kit (Microgen, Surrey, UK). Disc agar diffusion method (Modified Kirby-Bauer's) following Clinical and Laboratory Standards Institute (CLSI 2018) guidelines was used in antimicrobial susceptibility testing. The results were interpreted and managed using WHONET 5.6 software (WHO, Switzerland). Oxacillin resistant screening agar base (ORSAB) culture was used to determine phenotypic methicillin resistance. Polymerase chain reaction (PCR) was carried out to determine the presence of cfr-gene. Results: A total of 81 S. aureus isolates were phenotypically identified. Of this number, 46.91% (38/81) were MRSA; Healthcare workers (39.5%), Outpatient (28.9%), In patient (21%), Security men and Cleaners (5.3% each). Importantly linezolid resistance rate among the MRSA isolates was 44.7%. Analysis of antimicrobial susceptibility profile also showed a multiple antibiotics resistance burden of MDR (5.9%), possible XDR (47.1%), XDR (41.1%) and PDR (5.9%) amongst LR-MRSA. About 52.9% (9/17) of LR-MRSA harbored the cfr gene. Conclusions: This is the first report to document cfr gene in LR-MRSA strains in Sokoto. The cfr gene was found among the studied LR-MRSA strains and if cfr-mediated linezolid resistance is not properly checked, its phenotypic expression may result in an outbreak of multiple antibiotic resistant strains.
Objetivo: avaliar a incidência de resistência linezolida cfr-mediada entre os isolados de MRSA dos hospitais do Estado de Sokoto. Métodos: A identificação das espécies bacterianas foi realizada com Microgen™ Staph-ID System kit (Microgen, Surrey, UK). Método de difusão em ágar de disco (Kirby-Bauer modificado) seguindo as diretrizes do Clinical and Laboratory Standards Institute (CLSI 2018). O resultado foi interpretado e gerido com WHONET 5.6 (OMS, Suíça) software. A cultura ORSAB (Oxacillin resistant screening agar) foi utilizada para determinar a resistência fenotípica à meticilina. A PCR foi realizada para determinar a presença de cfr-gene. Resultados: um total de 81 isolados de S. aureus foi identificada fenotipicamente. Desse número, 46,91% (38/81) eram de MRSA; Profissionais de saúde (39,5%), Ambulatoriais (28,9%), Em paciente (21%), Homens de segurança e Limpadores (5,3% cada). A taxa de resistência linezolida entre os isolados de MRSA foi de 44,7%. A análise do perfil de sensibilidade antimicrobiana também mostrou uma carga de resistência a antibióticos múltiplos de MDR (5,9%), possível XDR (47,1%), XDR (41,1%) e PDR (5,9%) entre LR-MRSA. Um total de, 52,9% (9/17) da LR-MRSA abrigava o gene cfr. Conclusões: Este é o primeiro relatório a documentar o cfr-gen nas estirpes LR-MRSA em Sokoto. O gene cfr está presente entre as cepas estudadas de LR-MRSA, e se a resistência cfr-mediated linezolida não for adequadamente verificada, sua expressão fenotípica pode resultar em um surto de múltiplas cepas resistentes a antibióticos.
Assuntos
Resistência ao Cloranfenicol , Resistência Microbiana a Medicamentos , LinezolidaRESUMO
Objective To investigate the mechanism of linezolid resistance in methicillin-resistant Staphylococcus epidermidis ( MRSE) strains isolated in Hangzhou area. Methods Twenty-three linezolid-re-sistant Staphylococcus epidermidis ( LRSE) strains were isolated from the patients with septicaemia, urinary tract infection or infectious pleuritis in several hospitals in Hangzhou area during May, 2013 to April, 2015. The minimal inhibition concentrations ( MICs) of thirteen different antibiotics against the LRSE strains were detected by using E-test. Pulsed-field gel electrophoresis ( PFGE) and cluster analysis were performed for homology analysis. Correlations between linezolid resistance in the LRSE strains and G2576T mutation at theⅤ functional region of 23S rRNA gene or cfr gene were determined by PCR and sequencing analysis. Re-sults The MICs of linezolid to 15 LRSE strains were higher than 256 μg/ml while to the other 8 LRSE strains were 6 or 8 μg/ml. All of the 23 LRSE strains were resistant to both oxacillin and cefoxitin. Among the LRSE strains with high linezolid MICs (MIC>256 μg/ml), LRSE1 and LRSE2, LRSE3-LRSE6 and LRSE9-LRSE12 respectively belonged to the same clone line and came from the same hospital. All of the 23 LRSE strains carried the cfr gene. Moreover, the G2576T mutation at theⅤfunctional region of 23S rRNA gene was detected in the 15 LRSE strains with high linezolid MICs ( MIC>256 μg/ml ) , but not in the 8 strains with lower linezolid MICs ( MIC=6 or 8 μg/ml) . Conclusion There are significant differences in linezolid resistance among LRSE strains isolated in Hangzhou area. The LRSE strains are methicillin-resist-ant coagulase negative Staphylococcus ( MRCNS) strains and widely distributed. The linezolid resistance in LRSE strains is related to the G2576T mutation at theⅤfunctional region of 23S rRNA gene and cfr gene.
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Background & objectives: Linezolid, a member of the oxazolidinone class of antibiotics, has been an effective therapeutic option to treat severe infections caused by multidrug resistant Gram positive bacteria. Emergence of linezolid resistant clinical strains is a serious issue in the healthcare settings worldwide. We report here the molecular characterization of a linezolid resistant clinical isolate of Staphylococcus haemolyticus from India. Methods: The species of the clinical isolate was identified by 16S rRNA gene sequencing. The minimum inhibitory concentrations (MICs) of linezolid, clindamycin, chloramphenicol and oxacillin were determined by E-test method. To elucidate the mechanism of linezolid-resistance, presence of cfr gene (chloramphenicol florfenicol resistance) and mutations in 23S rRNA and ribosomal proteins (L3, L4 and L22) were investigated. Staphylococcal Cassette Chromosome mec (SCCmec) typing was performed by multiplex PCR. Results: The study documented a rare clinical S. haemolyticus strain with three independent mechanisms of linezolid-resistance. The strain carried cfr gene, the only known transmissible mechanism of linezolid-resistance. The strain also possessed resistance-conferring mutations such as G2576T in domain V of 23S rRNA gene and Met156Thr in L3 ribosomal protein. The other ribosomal proteins (L4 and L22) did not exhibit mutations accountable for linezolid-resistance. Restriction digestion by NheI revealed that all the alleles of 23S rRNA gene were mutated. The isolate showed elevated MIC values (>256 μg ml-1) of linezolid, clindamycin, chloramphenicol and oxacillin. Methicillin resistance was conferred by type I SCCmec element. The strain also harboured lsa(B) gene which encodes an ABC transporter that can efflux clindamycin. Interpretation & conclusions: The present study reports the first clinical strain from India with transmissible and multiple mechanisms of linezolid-resistance. Judicious use of linezolid in clinical practice and proper surveillance of cfr-positive strains are of utmost importance to safeguard the efficacy of linezolid.