Staphylococcal cassette chromosome mec elements from Staphylococcus intermedius group (SIG) isolates from dogs in a center for veterinary diagnostics in Brazil / Cassetes cromossômicos estafilocócicos mec de isolados do grupo Staphylococcus intermedius (GSI) de cães em um centro veterinário de diagnósticos no Brasil

ABSTRACT: Methicillin resistance in the Staphylococcus intermedius group (SIG) has emerged in small animal practice. Methicillin-resistant SIG (MRSIG) members have been implicated as causes of infections in both companion animals and humans. Staphylococcal cassette chromosome mec (SCCmec) elements carry the mecA/C genes, which encode for the transpeptidase PBP2a (PBP2') responsible for β-lactam antibiotic resistance in staphylococci. This study examined the SCCmec types of MRSIG isolates from different clinical specimens of dogs that exhibited methicillin MIC ≥ 0.5 μg/mL by an automated identification and susceptibility system in a Center for Veterinary Diagnostics in São Paulo, Brazil. Susceptibility to methicillin was determined by broth microdilution testing, and Oxoid® M.I.C.Evaluator® strips. PBP2a production was detected using a latex agglutination assay. SCCmec typing was performed according to the International Working Group on the Classification of Staphylococcal Cassette Chromosome Elements (IWG-SCC) guidelines. SCCmec type II (2A), SCCmec type III (3A), composite SCC structures consisting of a class A mec gene complex in addition to multiple ccr gene complexes, and non-typable SCCmec elements were reported in these MRSIG isolates. SCCmec type variants differing from those so far acknowledged by IWG-SCC were found, indicating new rearrangements in the genetic context of mecA in these canine MRSIG isolates.

RESUMO: A resistência à meticilina no grupo Staphylococcus intermedius (GSI) tem aumentado na clínica de pequenos animais. Membros GSI resistentes à meticilina (GSIRM) têm sido causas de infecções tanto em animais de companhia e humanos. Cassetes cromossômicos estafilocócicos mec (SCCmec) carregam os genes mecA/C, que codificam a transpeptidase PBP2a (PBP2') responsável pela resistência aos antibióticos β-lactâmicos em estafilococos. Nosso objetivo foi investigar os elementos SCCmec de GSIRM isolados de diferentes amostras clínicas de cães que exibiram CIM de meticilina ≥ 0,5 μg/mL por meio de um sistema automatizado em um Centro Veterinário de Diagnósticos em São Paulo, Brasil. A sensibilidade à meticilina foi determinada por meio do teste de microdiluição em caldo e fitas Oxoid® M.I.C.Evaluator®. A produção de PBP2a foi detectada usando um ensaio de aglutinação de látex. A tipagem dos elementos SCCmec foi realizada de acordo com as diretrizes do International Working Group on the Classification of Staphylococcal Cassette Chromosome Elements (IWG-SCC). SCCmec tipo II (2A), SCCmec tipo III (3A), SCC compostos de um complexo mec de classe A com múltiplos complexos ccr, e elementos SCCmec não tipáveis foram encontrados nesses isolados GSIRM. Variantes que diferem dos elementos SCCmec reconhecidos até o momento pelo IWG-SCC foram encontradas, indicando novos rearranjos no contexto genético de mecA nesses isolados GSIRM caninos.

High Prevalence of Methicillin-resistant Staphylococcus haemolyticus Isolated From Commensals in Healthy Adults

@#Introduction: S. haemolyticus is known to be commensals residing on human skin. However, their ability to develop as pathogens among the healthy community has becoming increasingly vital. Methods: In this study, a total of 49 non-duplicated samples of S. haemolyticus was isolated from the skin of healthy adults and confirmed via sodA gene sequencing method. Cefoxitin (30μg) disc diffusion test was performed to determine methicillin resistance among the S. haemolyticus isolates. The isolates were then subjected to mecA amplification and Staphylococcus Cassette Chromosome (SCCmec) typing of I, II, III, IV and V. Results: Interestingly, 59.2% of the S. haemolyticus commensal isolates were found to be methicillin-resistant (MRSH) while the remaining 40.8% was methicillin-sensitive (MSSH). Amplification of mecA gene showed that 43 isolates (87.8%) were positive while only six isolates were negative for the gene. A majority of the positive mecA isolates (90.7%) were discovered to harbour SCCmec Type II while the remaining 44.2% were Type V followed by 23.3% of Type I and 18.6% of Type IV. Only one of the isolates was found to be SCCmec Type III while another isolate, T187 was non-typeable. Conclusion: The data indicates the acquisition of SCCmec typing circulated among the commensal strains which could be a potential route of pathogenicity among the isolates.

Tipificación del cassette cromosómico estafilocócico de Staphylococcus aureus resistentes al meticilino en el estado de Aragua, Venezuela / Typification of the staphylococcal chromosome cassette of methicillin-resistant Staphylococcus aureus in the state of Aragua, Venezuela

RESUMEN Objetivos: Tipificar el casette SCCmec en cepas de Staphylococcus aureus resistentes a meticilino (SARM) en aislados clínicos de centros de salud del Estado Aragua-Venezuela y comparar la presencia de los genotipos SCCmec entre los centros de salud del estado y según el tipo de infección. Materiales y métodos: Durante enero y agosto de 2015 se estudiaron 81 cepas SARM de cuatro centros de salud del estado de Aragua en Venezuela. La resistencia al meticilino se midió con el método de Kirby-Bauer con discos de oxacilina (1 µgr) y cefoxitina (30 µgr). El gen mecA y el SCCmec se analizaron por la técnica de reacción en cadena de polimerasa múltiple. Resultados: 55 aislados (67,9%) amplificaron el gen mecA, y 24 cepas (43,6%) amplificaron el SCCmec. El SCCmec I fue el más frecuente, seguido de SCCmecIV y SCCmec III, representaron el 62,5%, 25% y 12,5%, respectivamente. El SCCmec I fue predominante en el centro de salud A (80%), mientras que el SCCmec IV se encontró en el centro de salud B (60%) y C (100%). En el centro de salud D, 50% resultó ser SCCmec I y 50% SCCmec IVd. Se encontró relación entre el SCCmec y el centro de salud con significancia estadística. En infecciones de piel y tejidos blandos y en las respiratorias predominó el SCCmec I con 63,2% y 50% respectivamente. Conclusiones: La frecuencia de SCCmec I y IV permitirá establecer nuevas medidas en el uso y control de la resistencia a los antibióticos.

ABSTRACT Objective: Typify the SCCmec cassette in methicillin-resistant strains of Staphylococcus aureus in clinical isolates from health centers in the State of Aragua-Venezuela and compare the presence of SCCmec genotypes among the state health centers and according to the type of infection. Materials and methods: 81 MRSA strains from four health centers of the Aragua-Venezuela State were studied. Methicillin resistance was performed with the Kirby-Bauer method with oxacillin (1 µg) and cefoxitin (30 µg) disks. The mecA gene and SCCmec were analyzed by the multiple PCR technique. Results: Only 55 isolates (67.9%) amplified the mecA gene, and 24 strains (43.6%) amplified SCCmec. SCCmec type I was the most frequency, followed by SCCmec IV and SCCmec III, representing 62.5%, 25% and 12.5%, respectively. SCCmec I was predominant in health center A (80%), while in B and C 60% and 100% respectively were SCCmec IV. At health center D, 50% turned out to be SCCmec I and 50% SCCmec IVd. A relationship was found between the SCCmec and the health center with statistical significance. SCCmec I predominated in skin and soft tissue and respiratory infections with 63.2% and 50%, respectively. There was no association between genotype and type of infection with a p value greater than 0.05. Conclusions: The prevalence of SCCmec I and IV will allow establishing new measures in the use of antibiotics and epidemiological control.

Coagulase-negative staphylococci: a 20-year study on the antimicrobial resistance profile of blood culture isolates from a teaching hospital

ABSTRACT The increasing rates of nosocomial infection associated with coagulase-negative staphylococci (CoNS) were the rationale for this study, aiming to categorize oxacillin-resistant CoNS species recovered from blood culture specimens of inpatients at the UNESP Hospital das Clínicas in Botucatu, Brazil, over a 20-year period, and determine their sensitivity to other antimicrobial agents. The mecA gene was detected in 222 (74%) CoNS samples, and the four types of staphylococcal chromosomal cassette mec (SCCmec) were characterized in 19.4%, 3.6%, 54.5%, and 14.4% of specimens, respectively, for types I, II, III, and IV. Minimal inhibitory concentration (MIC) values to inhibit 50% (MIC50) and 90% (MIC90) of specimens were, respectively, 2 and >256 µL/mL for oxacillin, 1.5 and 2 µL/mL for vancomycin, 0.25 and 0.5 µL/mL for linezolid, 0.094 and 0.19 µL/mL for daptomycin, 0.19 and 0.5 µL/mL for quinupristin/dalfopristin, and 0.125 and 0.38 µL/mL for tigecycline. Resistance to oxacillin and tigecycline and intermediate resistance to quinupristin/dalfopristin were observed. Eight (2.7%) of all 300 CoNS specimens studied showed reduced susceptibility to vancomycin. Results from this study show high resistance rates of CoNS to antimicrobial agents, reflecting the necessity of using these drugs judiciously and controlling nosocomial dissemination of these pathogens.

Detection of heterogeneous vancomycin-intermediate Staphylococcus aureus: A preliminary report from south India

Background & objectives: Although there are reports of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) across the globe, there is a lack of reliable data on hVISA in India. The present study was undertaken to determine the rate of hVISA among the methicillin-resistant Staphylococcus aureus (MRSA) isolates, and to compare the brain heart infusion agar with vancomycin 4 ?g/ml (BHIV4) method with population analysis profile-area under the curve (PAP-AUC) method for the detection of hVISA and to study the distribution of mobile genetic element that carries methicillin-resistance gene SCCmec (Staphylococcal cassette chromosome mec) types among these isolates. Methods: BHIV4 and PAP-AUC methods were employed to detect hVISA among 500 clinical isolates of MRSA. SCCmec typing of these isolates was performed by multiplex polymerase chain reaction. The clinical presentation, treatment with vancomycin and outcome was documented for patients with hVISA. Results: The rate of hVISA was 12.4 per cent by PAP-AUC method. Sensitivity, specificity, PPV, NPV and kappa agreement of BHIV4 with PAP-AUC was 58.06, 93.15, 54.55, 94.01 per cent and 0.498, respectively. The isolation of hVISA was significantly (P<0.01) higher in patients admitted to intensive care units and wards than in patients attending the outpatient departments. Only 38 per cent of the patients received vancomycin as therapy. Majority of the hVISA isolates carried SCCmec type V or IV. Interpretation & conclusions: The rate of hVISA isolation in our study was 12.4 per cent. The sensitivity of the BHIV4 screening test was low, and was in moderate agreement with PAP-AUC test. SCCmec type V was the predominant type seen in half of the isolates. More studies need to be done in different parts of the country on a large number of isolates to confirm our findings.

Differences in resistance profiles and virulence genes among methicillin-resistant and methicillin-susceptible Staphylococcus aureus of different lineages at a public tertiary hospital

Abstract INTRODUCTION Staphylococcus aureus is a major nosocomial pathogen that is associated with high virulence and the rapid development of drug resistance. METHODS We analyzed and compared the antimicrobial resistance, virulence profiles, and molecular epidemiology of 67 S. aureus strains, including 36 methicillin-sensitive (MSSA) and 31 methicillin-resistant (MRSA) strains recovered from a public hospital located in south-eastern Brazil. RESULTS The clones circulating in this hospital presented a great diversity, and the majority of the strains were related to clones responsible for causing worldwide epidemics: these included USA100 (New York/Japan clone), USA300, and USA600. The 31 MRSA (22 SCCmecII and 9 SCCmecIV) and 36 MSSA strains exhibited low resistance against gentamicin and trimethoprim/sulfamethoxazole. No MRSA strain showed resistance to tetracycline. Virulence gene carriage was more diverse and abundant in MSSA than in MRSA. Of the evaluated adhesion-related genes, ebpS was the most prevalent in both MSSA and MRSA strains. The genes bbp and cna showed a strong association with MSSA strains. CONCLUSIONS Our findings reinforce the idea that MSSA and MRSA strains should be carefully monitored, owing to their high pathogenic potential.

Analysis of antimicrobial resistance and staphylococcal cassette chromosome mec ( SCCmec ) in 99 Staphylococcus epidermidis strains isolated from early pregnancy cervical swabs and external environ-ment / 中华微生物学和免疫学杂志

Objective To analyze the antimicrobial resistance, distribution of resistance genes and staphylococcal cassette chromosome mec ( SCCmec) in 99 strains of mecA gene-positive Staphylococcus epi-dermidis strains isolated from early pregnancy cervical swabs and external environment in Beijing Chaoyang District from 2015 to 2016. Methods Kirby-Bauer disk diffusion method was performed to detect the sus-ceptibility of the 99 Staphylococcus epidermidis strains to cefoxitin. Microbroth dilution method was used to test their susceptibility to vancomycin, daptomycin, penicillin, erythromycin, compound sulfamethoxazole, tetracycline, ciprofloxacin, clindamycin, gentamicin and chloramphenicol. PCR was used to detect drug re-sistance genes of ermA, ermB, ermC, msrA, norA1, norA2, sul1, sul2, sul3, aac(6')/aph(2″), ant(4', 4″), ant(6) and tetM and to analyze the SCCmec types ofⅠ, Ⅱ, Ⅲ, Ⅳa, Ⅳb, Ⅳc, Ⅳd and Ⅴ. The results were compared with those of capillary electrophoresis. SPSS was used for data analysis. Results All of the 99 mecA-positive Staphylococcus epidermidis strains were sensitive to vancomycin and 93. 94％ of them were sensitive to datomycin. The resistance rates to penicillin, erythromycin, cefoxitin, compound sulfame-thoxazole, tetracycline, ciprofloxacin, clindamycin, gentamicin and chloramphenicol were 97. 98％, 85. 86％, 79. 80％, 52. 54％, 27. 27％, 43. 43％, 36. 36％, 23. 23％ and 11. 11％. The strains that car-ried the genes of norA1, norA2, ermA, ermB, ermC, msrA, sul1, sul2, sul3, aac(6')/aph(2″), ant(4', 4″), ant(6) and tetM accounted for 100％, 93. 94％, 0. 00％, 3. 03％, 17. 17％, 57. 58％, 50. 51％, 12. 12％, 4. 04％, 30. 30％, 8. 08％, 4. 04％ and 25. 26％, respectively. Among the 99 strains, 5. 05％, 0％, 43. 43％, 10. 10％, 0. 00％, 3. 03％, 3. 03％ and 19. 19％ belonged to SCCmecⅠ, Ⅱ, Ⅲ, Ⅳa,Ⅳb,Ⅳc,Ⅳd andⅤ, respectively, and 4. 04％ (4/99) were positive to two SCCmec types. The types of 12. 12％ (12/99) of the strains were unidentified. Conclusions All of the 99 strains of mecA-positive Staphylococcus epidermidis were sensitive to vancomycin. Among them, the strains carrying multidrug resist-ance genes accounted for 89. 90％. The main mechanisms of resistance to macrolides, sulfonamides and ami-noglycosides in local strains were related to the resistance genes of msrA, sul1 and aac ( 6')/aph ( 2″) . SCCmec Ⅲ was the prevalent type. There were 88. 37％ of SCCmec Ⅲ type strains and 75％ of unknown type strains carrying multiple resistance genes. Apart from that, the isolated strains of other SCCmecⅢtypes all carried multiple resistance genes.

Características moleculares de Staphylococcus aureus susceptível à vancomicina poderia ajudar a prever falhas no tratamento devido a reduzida susceptibilidade à vancomicina / Molecular characteristics of vancomycin-susceptible Staphylococcus aureus could help to predict treatment failure due to reduced vancomycin susceptibility / Características moleculares de Staphylococcus aureus susceptible a la vancomicina podría ayudar a predecir fallas en el tratamiento debido a la reducida susceptibilidad a la vancomicina

Justificativa e Objetivos: Staphylococcus aureus resistente à meticilina (MRSA) é uma das causas mais frequentes de infecções relacionadas à assistência à saúde e comunitárias, e com seu avanço, a vancomicina tornou-se a principal opção terapêutica. Entretanto, o seu uso indiscriminado favoreceu o surgimento de MRSA com reduzida suscetibilidade à vancomicina, comumente associados com falhas no tratamento, bacteremia persistente, hospitalização prolongada e desfechos clínicos adversos. Este estudo avaliou a ocorrência de MRSA com reduzida suscetibilidade à vancomicina e determinou algumas características moleculares em comparação com MRSA suscetível à vancomicina (VS-MRSA). Métodos: Determinação do perfil de suscetibilidade aos antimicrobianos, a concentração inibitória mínima (CIM) e concentração bactericida mínima (CBM) para vancomicina, tolerância à vancomicina, tipagem do SCCmec e agr foram realizadas em um total de 177 MRSA. Posteriormente, foram triados para hVISA por BHIA-3V e BHIA-6V e confirmados com a Análise do Perfil Populacional - Área Abaixo da Curva (PAP-AUC). Resultados: Os fenótipos VT-MRSA e hVISA foram encontrados em 13,6% e 5,1% dos isolados clínicos de MRSA, respectivamente, e a presença de hVISA foi estatisticamente significativa entre os isolados de VT-MRSA (p<0,05). Em VT-MRSA, SCCmec tipo II foi significativamente mais frequente do que em não-VT-MRSA, assim como a presença do agr grupo II. Conclusão: Características moleculares encontradas em MRSA são importantes para a epidemiologia, bem como para demonstrar um padrão em isolados com reduzida suscetibilidade à vancomicina. Testes não-convencionais para detecção destas características podem ser realizados para evitar a identificação errada de VS-MRSA que, consequentemente, resulta em falhas no tratamento com vancomicina.(AU)

Background and Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most frequent causes of healthcare-associated and community-acquired infections and with its advancement, vancomycin became the main therapeutic option. However, its indiscriminate use favored the emergence of MRSA with reduced susceptibility to vancomycin, commonly associated with vancomycin treatment failure, persistent bacteremia, prolonged hospitalization and adverse clinical outcome. This study evaluated the occurrence of MRSA with reduced vancomycin susceptibility and determined some molecular characteristics in comparison with vancomycin-susceptible MRSA (VS-MRSA). Methods: Determination of antimicrobial susceptibility profile, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for vancomycin, vancomycin-tolerance, SCCmec and agr typing were performed in a total of 177 MRSA. Thereafter, they were screened for hVISA by BHIA-3V and BHIA-6V and confirmed with population analysis profile - area under the curve method (PAP-AUC). Results: VT-MRSA and hVISA phenotypes were found in 13.6% and 5.1% of clinical isolates of MRSA, respectively, and the presence of hVISA was statistically significant among VT-MRSA isolates (p<0.05). In T-MRSA, SCCmec type II was significantly more frequent than in non-VT-MRSA, as well as the presence of agr group II. Conclusion: Molecular characteristics found in MRSA are important for epidemiology, as well as demonstrate a pattern in reduced vancomycin susceptibility isolates. Non-conventional tests for detection of these characteristics might be performed to prevent misidentification of VS-MRSA that, consequently, results in vancomycin treatment failures.(AU)

Justificación y objetivos: Staphylococcus aureus resistente a la meticilina (MRSA) es una de las causas más frecuentes de infecciones relacionadas con la asistencia sanitaria y comunitarias, y con su avance, a la vancomicina se ha convertido en la principal opción terapéutica. Sin embargo, su uso indiscriminado favoreció el surgimiento de MRSA con reducida susceptibilidad a la vancomicina, comúnmente asociados con fallas en el tratamiento, bacteriemia persistente, hospitalización prolongada y resultados clínicos adversos. Este estudio evaluó la ocurrencia de MRSA con reducida susceptibilidad a la vancomicina y determinó algunas características moleculares en comparación con MRSA susceptible a la vancomicina (VS-MRSA). Métodos: Determinación del perfil de susceptibilidad a los antimicrobianos, la concentración inhibitoria mínima (CIM) y la concentración bactericida mínima (CBM) para vancomicina, tolerancia a la vancomicina, tipificación del SCCmec y agr se realizaron en un total de 177 MRSA. Resultados: Los fenotipos VT-MRSA y hVISA se encontraron en el 13,6% y el 5,1% de los aislados clínicos de MRSA, respectivamente, y la presencia de hVISA fue estadísticamente significativa entre los aislados de VT-MRSA (p<0.05). En VT-MRSA, SCCmec tipo II fue significativamente más frecuente que en no-VT-MRSA, así como la presencia del agr grupo II. Conclusión: Características moleculares encontradas en MRSA son importantes para la epidemiología, así como para demostrar un patrón en aislados con reducida susceptibilidad a la vancomicina. Pruebas no convencionales para la detección de estas características pueden realizarse para evitar la identificación errónea de VS-MRSA que, consecuentemente, resulta en fallas en el tratamiento con vancomicina.(AU)

Tipos de spa no reportados en nuestro país en Staphylococcus aureus de pacientes adultos de un hospital escuela, Santa Fe, Argentina / Non reported spa types in our country in Staphylococcus aureus from adult patients of a school hospital, Santa Fe- Argentina

Staphylococcus aureus es un patógeno responsable de diversos cuadros clínicos. Los marcadores moleculares son útiles para el estudio de la epidemiología microbiana. Se estudiaron 22 aislamientos de S. aureus resistentes a meticilina (SARM) y 23 sensibles a meticilina (SASM) mediante mecA, cassette SCCmec, leucocidina de Panton Valentine (LPV) y polimorfismo spa; se analizaron datos de los pacientes. SASM predominó en muestras distintas de piel y partes blandas de internados, mientras SARM en partes blandas. Predominó el SCCmec tipo IV seguido del I. Se encontró baja presencia de LPV. En SARM hubo 11 tipos de spa diferentes, t019 fue el más frecuente y en pacientes ambulatorios. En SASM se hallaron 17 tipos con prevalencia del t189. El spa t002 estuvo presente en SASM y SARM. Se hallaron 11 tipos de spa no reportados en nuestro país.

Staphylococcus aureus is a pathogen associated a different kind of infection. Molecular markers are useful tools to study microbial epidemiology. Twenty two methicillin-resistant S. aureus (MRSA) and 23 methicillin-susceptible S. aureus (MSSA) were studied by mecA gene, SCCmec cassette, Panton Valentine leucocidin (PVL) and spa polymorphism. The clinical data patients were analyzed. MSSA was prevalent in samples different from skin and soft tissue (SST) and in hospitalized patients, whereas MRSA in SST. SCCmec type IV was predominant, followed spa; by type I. Low presence of PVL was found. In MRSA 11 different types of spa were detected, SCCmec; t019 was the most frequent and associated with outpatient, 17 types were found in MSSA and Panton Valentine t189 was prevalent. spa t002 was present in MSSA and MRSA. We found 11 types of spa not leucocidin reported in our country.

Methicillin-resistant Staphylococcus aureus isolated from an intensive care unit in Minas Gerais, Brazil, over a six-year period

ABSTRACT To characterize methicillin-resistant Staphylococcus aureus isolates from an intensive care unit of a tertiary-care teaching hospital, between 2005 and 2010. A total of 45 isolates were recovered from patients admitted to the intensive care unit in the study period. Resistance rates higher than 80% were found for clindamycin (100%), erythromycin (100%), levofloxacin (100%), azithromycin (97.7%), rifampin (88.8%), and gentamycin (86.6%). The SCCmec typing revealed that the isolates harbored the types III (66.7%), II (17.8%), IV (4.4%), and I (2.2%). Four (8.9%) isolates carried non-typeable cassettes. Most (66.7%) of the isolates were related to the Brazilian endemic clone from CC8/SCCmec III, which was prevalent (89.3%) between 2005 and 2007, while the USA100/CC5/SCCmec II lineage emerged in 2007 and was more frequent in the last few years. The study showed high rates of antimicrobial resistance among methicillin-resistant S. aureus isolates and the replacement of Brazilian clone, a well-established hospital lineage, by the USA100 in the late 2000s, at the intensive care unit under study.

Drug resistance analysis and Staphylococcal cassette chromosome SCCmec genotypes of methicillin resistant Staphylococcus aureus / 国际检验医学杂志

Objective To investigate the drug resistance situation and Staphylococcal cassette chromosome mec(SCCmec) genotypes of methicillin resistant Staphylococcus aureus (M RSA ) strains isolated from Shang-hai Putuo District People′s Hospital in order to provide a theoretical basis for predicting the trend of drug re-sistant bacterial strains and clinical treatment and prevention of MRSA .Methods Three hundreds and eighty clinically isolated MRSA strains in this hospital were collected from January 2012 to December 2016 .The in vitro drug susceptibility test was performed by adopting the broth microdilution method .The SCCmec geno-types were examined by adopting the multiplex polymerase chain reaction .Results All strains were sensitive to linezolid and vancomycin ,the sensitivity rate was 100 .0％ ;the resistance rates to rifampicin and cotrimox-azole were lower ,which were 5 .0％ and 7 .6％ respectively ;but the strains were highly resistant to erythromy-cin ,levofloxacin and tetracycline ,with the resistance rate of 100 .0％ ,94 .2％ ,93 .4％ and 90 .0％ .The resist-ance rate to penicillin was 100 .0％ .Among 380 strains of MRSA ,there were 281 strains(73 .9％ ) of SCCmecⅡ ,59 strains (15 .5％ ) of SCCmecⅢand 5 strains (1 .3％ ) of SCCmecⅣa ,other 35 strains(9 .2％ ) of MRSA could not be classified .Conclusion M RSA strains isolated in the Shanghai Putuo District People′s Hospital are mainly the type SCCmecⅡ ,w hich has the multi-drug resistant characteristics ,and the drug resistance spec-trum of different SCCmec genotypes is different .

Antimicrobial resistance features and molecular typing of clinically isola-ted m ethicillin-resistant Staphylococcus aureus / 中国感染控制杂志

Objective To study antimicrobial resistance and genotyping of methicillin-resistant Staphylococcus au-reus(MRSA). Methods A total of 967 no-repetitive strains of Staphylococcus aureus(S.aureus)isolated from a hospital between January 2014 and November 2015 were collected,antimicrobial susceptibility testing,mecA gene,and Panton-Valentine leukocidin gene(PVL gene)were detected;staphylococcal cassette chromosome mec(SCCmec)typing,multilocus sequence typing(MLST),S.aureus protein A(spa)gene typing,and S.aureus ac-cessory gene regulator(agr)typing were performed with multiplex polymerase chain reaction. Results Of 967 strains of S.aureus,210(21.72%)were MRSA;detection rate of MRSA from sputum specimen was higher than that of skin and soft tissue specimen(68.09% vs 1 1.83% ,P<0.05);vancomycin- and linezolid-resistant S.aureus strains were not found,susceptibility rates of MRSA to gentamicin,tetracycline,erythromycin,clindamycin,levo-floxacin,ciprofloxacin,moxifloxacin,nitrofurantoin,and rifampicin were all lower than those of methicillin-sensi-tive Staphylococcus aureus(MSSA),differences were all statistically significant(all P<0.05);antimicrobial sus-ceptibility rate of MRSA to compound sulfamethoxazole was higher than MSSA,difference was significant(P<0.05). Susceptibility rates of MRSA isolated from skin and soft tissue to gentamicin,levofloxacin,ciprofloxacin,moxifloxacin,and rifampicin were 86.90% -95.24%,while MRSA isolated from sputum were only 1.56% -15.63%.Of 967 strains of S.aureus,210 harbored mecA gene,10 harbored PVL gene,8(3.81%)of 210 MRSA strains weren't typed. The main types of MLST,SCCmec,spa,and agr were ST 239(n= 177 strains),type Ⅲ(n= 177 strains),t 030(n= 177 strains),and typeⅠ(n= 196 strains)respectively.Conclusion The main epidemic clone of MRSA strain in this hospital is ST239-MRSA-SCCmec III-t030,antimicrobial resistance is serious,monitoring on drug-resistant strains in hospital should be strengthened.

Community-acquired methicillin-resistant Staphylococcus aureus carrying SCCmec type IV and V isolated from healthy children attending public daycares in northeastern Brazil

Abstract Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) have increasingly been reported in healthy communities. This study aimed to assess the rate of S. aureus in general and MRSA in particular from nasal secretion of children in daycare centers in Vitória da Conquista, Brazil. The isolates were identified based on morphology, biochemical tests and by PCR. Detection of virulence genes, biofilm production, and susceptibility test by disk diffusion agar were performed. MRSA isolates were characterized by spa, SCCmec, and multilocus sequence typing (MLST). S. aureus were recovered from 70 (47.3%) of 148 children. Among the 11 MRSA strains (15.7%), two SCCmec types (IV and V) were detected. MLST identified four STs related to three clonal complexes (CC): 5, 45, and 398. Four spa types were found circulating in this setting. Resistance of S. aureus isolates to ampicillin, erythromycin, ciprofloxacin, clindamycin, and tetracycline was 80%, 32.8%, 7.1%, 7.1% and 4.3%, respectively. One isolate presented intermediate resistance to vancomycin detected by Etest methodology. All strains were biofilm producers. The virulence genes seb, sec, spa, and pvl were detected in some isolates. This study revealed a high rate of children carrying MRSA among healthy attendees in daycare centers in Vitória da Conquista, Brazil.

Characterization of biofilm formation, antimicrobial resistance, and staphylococcal cassette chromosome mec analysis of methicillin resistant Staphylococcus hominis from blood cultures of children

Abstract INTRODUCTION: Methicillin resistant Staphylococcus hominis (MRSHo) has been recognized as an important human pathogen, particularly in immunocompromised patients. METHODS: A total of 19 S. hominis isolates were collected from children at the Children's Medical Centre, Tehran, Iran, from March 2012 to February 2013. MRSHo susceptibility against 13 antimicrobial and 3 antiseptic agents was determined using disk diffusion (DAD) and minimum inhibitory concentration (MIC), respectively. All isolates were subjected to polymerase chain reaction (PCR) assay for 15 distinct resistance genes, staphylococcal cassette chromosome mec (SCCmec), and arginine catabolic mobile elements (ACMEs). Biofilm production of the isolates was determined using a colorimetric microtiter plate assay. RESULTS: Of the 19 isolates, 16 were resistant to oxacillin and harbored mecA. High resistance was also observed against trimethoprim/sulfamethoxazole (81.2%). All MRSHo isolates were susceptible to the three disinfectants tested (Septicidine-PC, Septi turbo, and Sayacept-HP). In total, 15 (78.9%) isolates produced biofilms. Three isolates had SCCmec types (V and VIII), 13 were untypable (UT), and 5 had ACME type II. CONCLUSIONS: The results indicate that MRSHo with high antibiotic resistance and unknown SCCmec might become a serious problem in the future for the treatment of patients such as children.

A Review of Staphylococcal Cassette Chromosome mec (SCCmec) Types in Coagulase-Negative Staphylococci (CoNS) Species

Coagulase-negative staphylococci (CoNS) are considered low pathogenic organisms. However, they are progressively causing more serious infections with time because they have adapted well to various antibiotics owing to their ability to form biofilms. Few studies have been conducted on CoNS in both, hospital and community-acquired settings, especially in Malaysia. Thus, it is important to study their species and gene distributions. A mobile genetic element, staphylococcal cassette chromosome mec (SCCmec), plays an important role in staphylococci pathogenesis. Among CoNS, SCCmec has been studied less frequently than Staphylococcus aureus (coagulase-positive staphylococci). A recent study (8) conducted in Malaysia successfully detected SCCmec type I to VIII as well as several new combination patterns in CoNS species, particularly Staphylococcus epidermidis. However, data are still limited, and further research is warranted. This paper provides a review on SCCmec types among CoNS species.

Characteristics, Detection And Typing Methods Of Community Acquired Methicillin Resistant Staphylococcus Aureus (CA-MRSA) – A Review

@#Staphylococcus aureus aregram positive cocci which colonizethe skin and mucous membranes particularly the anterior nares. Prevalence of nosocomial infections associated with methicillin resistant S. aureus have been reported in hospitals (HA-MRSA) for over five decades. Recently,community-acquired MRSA (CA-MRSA) has emerged as a cause of skin and soft tissue infections in healthy individuals. These strains are sensitive to antimicrobials, carry genes for Panton-Valentine leukocidin (PVL) toxin and belong to the staphylococcal cassette chromosome (SCC) mec type IV or V. The suspected mode of transmission involves close contact with carriers leading to skin or nasal colonization that resultin subsequent active infection. Molecular typing is used to determine the mode of transmission of CA-MRSA in the community.General typing methods such as pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) and specific methods for Staphylococci such as SCCmec typing and spa typing have the capability to characterize bacterial chromosomes and mobile genetic elements. Combination of these molecular typing methods is necessary as each method has its own advantages with respect to discriminatory power, rapidity, cost effectiveness, reproducibility, and ease of performance.

Homologous SCCmec elements in clinical isolates of methicillin-resistant Staphylococcus epidermidis carrying psm-mec / 西安交通大学学报(医学版)

Objective To investigate SCCmec types in clinical isolates of methicillin-resistant Staphylococcus epidermidis (MRSE) carrying psm-mec.Methods We collected 165 strains of Staphylococcus epidermidis identified by automated microbiological identification system and screened MRSE by PCR amplification of esp and mecA gene.Strains with psm-mec were identified by amplification of psm-mec,fudoh and p221 DNA fragment;mec,ccr and SCCmec typing was conducted by multiplex PCR assay.Results Among 138 strains of MRSE,29 strains were identified as MRSE with psm-mec,and the carrying rate was 17.58%.Results of mec and ccr typing by multiple PCR showed that MRSE with psm-mec carried Class A mec,but the ccr type had obvious diversity.Results of SCCmec typing showed that all strains with psm-mec belonged to type Ⅱ and/or Ⅲ SCCmec.Conclusion Clinical isolates of MRSE with psm-mec carry homologous type Ⅱ and/or Ⅲ SCCmec harboring Class A mec.

Antimicrobial resistance and molecular epidemiology of 116 strains of me-thicillin-resistant Staphylococcus aureu in Xuzhou area / 中国感染控制杂志

Objective To investigate infection status and antimicrobial resistance mechanism of methicillin-resistant Staphylococcusaureus(MRSA),and provide reference for the rational antimicrobial use in clinic. Methods Staphylococcusaureus (SA)isolated from various specimens in Xuzhou area in 2012-2015 were collected,MR-SA strains were preliminarily screened by cefoxitin disk diffusion method,and confirmed by amplification of mecA gene,antimicrobial resistance of MRSA was determined by Kirby-Bauer method,minimal inhibitory concentration (MIC)was measured by E-test method,genotypes of staphylococcal chromosomal cassette mec(SCCmec)were de-termined by multiplex PCR. Results A total of 116 strains of MRSA were identified among 210 SA strains in 2012-2015,114 of which were positive for mecA gene,the total detection rate of MRSA was 55.24% . Susceptibility rates of MRSA to vancomycin,quinupristin/dalfopristin,and linezolid were all 100% ,resistance rates of MRSA to chloramphenicol and furantoin were both low,which were 15.52% and 1.72% respectively,resistance rates of MR-SA to 10 kinds of antimicrobial agents were all>80% ;resistance rates of MRSA to penicillins,aminoglycosides, macrolides,quinolones,sulfanilamide,rifampicin,tetracycline,and clindamycin were all higher than methicillin-sensitive Staphylococcusaureus(MSSA). MICs of vancomycin to MRSA in 2012-2015 were all 1.0μg/mL,MIC90 were all 1.5μg/mL,one MRSA isolate was with a vancomycin MIC of 2.0μg/mL in 2015. MRSA typing results of 116 MRSA isolates showed that SCCmec II,SCCmec III,and SCCmec IV accounted for 9.48% (n= 11),73.28% (n= 85),and 1.72% (Iva,n= 2;IVb,n= 2)respectively,13.79% (n= 16)of MRSA isolates were nontypeable, SCCmec I and SCCmec V type strains were not found. Conclusion MRSA is seriously multidrug-resistant,the drift has not been discovered in MIC value of vancomycin against MRSA,the major SCCmec genotype of MRSA is SCCmec III,infection control measures should be taken to control MRSA infection.

Coagulase-negative staphylococci in Southern Brazil: looking toward its high diversity

Abstract: INTRODUCTION: Coagulase-negative staphylococci (CoNS) are the most prevalent pathogens in nosocomial infections and may serve as a reservoir of mobile genetic elements such as the staphylococcal cassette chromosome mec (SCCmec) encoding methicillin resistance. Molecular characterization of SCCmec types combined with advanced molecular typing techniques may provide essential information for understanding the evolution and epidemiology of CoNS infections. We therefore aimed to investigate the SCCmec distribution, multidrug-resistance (MDR), and biofilm formation in CoNS blood culture isolates from a hospital in Southern Brazil. METHODS: We analyzed 136 CoNS blood culture isolates obtained during 2002-2004 from patients admitted to a tertiary care hospital in Brazil. SCCmec types I to V were determined using multiplex PCR. The clonal relationship of Staphylococcus epidermidis was determined using pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Molecular epidemiological data were interpreted along with data on biofilm formation, presence of the icaD gene, and MDR. RESULTS: The most prevalent species were S. epidermidis, Staphylococcus haemolyticus, and Staphylococcus hominis harboring mainly SCCmec types II, III, and V. Overall, the presence of multiple SCCmec was associated with non-MDR, except for S. epidermidis. S. epidermidis isolates showed a high prevalence of icaD, but had low phenotypic biofilm formation. PFGE and MLST revealed high genetic diversity in the S. epidermidis population. CONCLUSIONS: Our results suggest a major shift in SCCmec types within a short period and reveal a different behavior of S. epidermidis with regard to the association between the presence of multiple SCCmec types and MDR profile.

Infecciones por Staphylococcus aureus resistente a la meticilina adquirido en la comunidad en pacientes de Villavicencio, Colombia / Community-acquired methicillin resistant Staphylococcus aureus infections in Villavicencio, Colombia

Introducción: los Staphylococcus aureus son patógenos muy versátiles, con capacidad de causar un gran rango de enfermedades en los humanos. Sin embargo, el papel que juegan sus factores de virulencia en el desarrollo de las infecciones no se ha entendido completamente. Algunos tipos clonales están muy bien equipados para causar enfermedad en todas las personas, mientras que otros causan enfermedad solo a algunos miembros de una comunidad. Objetivo: determinar la prevalencia de infecciones por Staphylococcus aureus resistente a meticilina adquiridas en la comunidad en pacientes de la ciudad de Villavicencio, Colombia. Métodos: estudio descriptivo, prospectivo de corte transversal, en 46 muestras obtenidas de absceso, secreción, sangre, orina, líquido pericárdico, líquido pleural, aspirado traqueal, forúnculo. Los individuos participantes no estuvieron hospitalizados en los últimos meses, ni recibieron tratamiento antimicrobiano y no presentaron signos y/o síntomas clínicos. Los aislamientos fueron identificados por pruebas convencionales microbiológicas y se determinó la susceptibilidad antimicrobiana para los diferentes antibióticos a través de MicroScan™ Pos Combo Panel Type pc 24 (Dade Behring, USA). Se detectaron los genes nuc, mecA y LukS-PV relacionados con la identificación y virulencia de esta especie. Resultados: de las 46 muestras analizadas, el 100 por ciento resultaron positivas para S. aureus, de éstas 46 (100 %) fueron resistentes a meticilina y 44 (95,6 por ciento) presentaron el gen para la LPV. Conclusiones: en Colombia y específicamente en Villavicencio poco se conoce de la epidemiologia del SARM- AC. Deben realizarse estudios de vigilancia epidemiológica y tipificación molecular que nos acerquen a entender más el comportamiento de su epidemiologia y así mismo diseñar mejores estrategias de prevención y control(AU)

Introduction: staphylococcus aureus is a very versatile pathogen, with a capacity to cause a great range of conditions in humans. However, the role played by its virulence factors in the development of infection is not thoroughly understood. Some clonal types are very well equipped to cause disease in all persons, whereas others only affect some members of a community. Objective: determine the prevalence of community-acquired methicillin resistant Staphylococcus aureus infections in patients from the city of Villavicencio in Colombia. Methods: a descriptive cross-sectional prospective study was conducted of 46 samples obtained from abscesses, secretions, blood, urine, pericardial fluid, pleural fluid, tracheal aspirates and boils. Participants had not been hospitalized in recent months nor had they received any antimicrobial treatment, and they did not present any clinical signs and/or symptoms. The isolates were identified by means of conventional microbiological tests. Antimicrobial susceptibility to the various antibiotics was determined using MicroScan™ Pos Combo Panel Type pc 24 (Dade Behring, USA). The genes nuc, mecA and LukS-PV were detected. These are related to the identification and virulence of the study species. Results: of the 46 samples analyzed, 46 (100 percent) were positive for S. aureus, 46 (100 percent) were resistant to methicillin and 44 (95.6 percent) contained the LPV gene. Conclusions: in Colombia and specifically in Villavicencio, little is known about the epidemiology of CA-MRSA. Epidemiological screening and molecular typing studies should be conducted to gain insight into the epidemiology of CA-MRSA and design better prevention and control strategies(AU)