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Chinese Journal of Epidemiology ; (12): 982-989, 2023.
Article in Chinese | WPRIM | ID: wpr-985623


Objective: To understand the population structure of food-borne Staphylococcus (S.) aureus in China. Methods: Whole genome sequencing was used to analyze 763 food-borne S. aureus strains from 16 provinces in China from 2006 to 2020. Multilocus sequence typing (MLST), staphylococcal protein A gene (spa) typing, and staphylococcal chromosome cassettemec (SCCmec) typing were conducted, and minimum spanning tree based on ST types (STs) was constructed by BioNumerics 7.5 software. Thirty-one S. aureus strains isolated from imported food products were also included in constructing the genome phylogenetic tree. Results: A total of 90 STs (20 novel types) and 160 spa types were detected in the 763 S. aureus isolates. The 72 STs (72/90, 80.0%) were related to 22 clone complexes. The predominant clone complexes were CC7, CC1, CC5, CC398, CC188, CC59, CC6, CC88, CC15, and CC25, accounting for 82.44% (629/763) of the total. The STs and spa types in the predominant clone complexes changed over the years. The methicillin-resistant S. aureus (MRSA) detection rate was 7.60%, and 7 SCCmec types were identified. The ST59-t437-Ⅳa (17.24%, 10/58), ST239-t030-Ⅲ (12.07%, 7/58), ST59-t437-Ⅴb (8.62%, 5/58), ST338-t437-Ⅴb (6.90%, 4/58) and ST338-t441-Ⅴb (6.90%, 4/58) were the main types in MRSA strains. The genome phylogenetic tree had two clades, and the strains with the same CC, ST, and spa types clustered together. All CC7 methicillin sensitive S. aureus strains were included in Clade1, while 21 clone complexes and all MRSA strains were in Clade2. The MRSA strains clustered according to the SCCmec and STs. The strains from imported food products in CC398, CC7, CC30, CC12, and CC188 had far distances from Chinese strains in the tree. Conclusions: In this study, the predominant clone complexes of food-borne strains were CC7, CC1, CC5, CC398, CC188, CC59, CC6, CC88, CC15, and CC25, which overlapped with the previously reported clone complexes of hospital and community-associated strains in China, suggesting that close attention needs to be paid to food, a vehicle of pathogen transmission in community and food poisoning.

Humans , Staphylococcus aureus/genetics , Methicillin-Resistant Staphylococcus aureus/genetics , Multilocus Sequence Typing , Phylogeny , Staphylococcal Infections/epidemiology , China/epidemiology
Actual. SIDA. infectol ; 30(108): 7-16, 20220000. graf, tab
Article in Spanish | LILACS, BINACIS | ID: biblio-1363203


Las infecciones de piel y partes blandas (IPPB) en niños son una de las principales causas de prescripción de antimicrobianos. El objetivo del estudio fue describir las características clínicas y microbiológicas de las IPPB ambulatorias de niños asistidos en dos hospitales zonales. Se realizó un estudio prospectivo entre el 1/11/2017 y el 1/11/2018. Se incluyeron pacientes entre 1 mes y 15 años internados en dos hospitales. Se evaluó: edad, sexo, localidad, factores predisponentes, tipo de IPPB, muestras biológicas realizadas, aislamiento microbiológico, tratamiento empírico indicado y evolución del cuadro. Se realizó antibiograma y determinación genética. Se calculó chi2, IC95, OR; α=5%. N= 94. 58,7% masculinos. 12 pacientes <1 año, 85 >1 año (promedio de edad 4 años, 1-15). El 36% de Tandil y 63,8% de Florencio Varela. El 59,6% corresponden a IPPB purulentas. Se aislaron microorganismos en un 59,6%. Los aislamientos principales: SAMR (40,4%), SAMS (7,4%), S. agalactiae (2,1%) y S. pyogenes (2,1%). El 100% de SAMR son portadores de gen mecA y SCCmec tipo IV, sin multirresistencia. No hubo diferencia estadística entre los factores de riesgo evaluados para el desarrollo de IPPB por SAMR. El 52,1% de los niños recibió tratamiento antibiótico combinado, siendo la más indicada TMS-SMX + CLI en 36 eventos. (38,3%). La evolución fue favorable: no hubo diferencia significativa entre el subgrupo que se aisló SAMR y el que no se aisló SAMR; 91,9% (34/37) y 92,6% (50/54) correspondientemente (chi2: 0,01; p= 0,97 IC95: 0,26-3,88). El principal agente etiológico fue SAMRco, debiendo adecuar los tratamientos a este microorganismo.

Skin and soft tissue infections (SSIs) in children are one of the main causes of antimicrobial prescription. The aim of the study was to describe the clinical and microbiological characteristics of outpatient SSIs in children attended in two hospitals. A prospective study was conducted between 11/1/2017 and 11/1/2018. Patients between 1 month and 15 years old, hospitalized were included. We evaluated: age, sex, locality, predisposing factors, type of IPPB, biological samples taken, microbiological isolation, empirical treatment indicated and evolution of the condition. An antibiogram and genetic determination were performed. Chi2, CI95, OR; α=5% were calculated. N= 94. 58.7% male. 12 patients <1 year, 85 >1 year (mean age 4 years, 1-15). 36% were from Tandil and 63.8% from Florencio Varela. 59.6% corresponded to purulent SSIs. The diagnostic yield was 59.6%. Main isolates: MRSA (40.4%), MSSA (7.4%), S. agalactiae (2.1%) and S. pyogenes (2.1%). 100% of MRSA carried the mecA gene and SCCmec type IV, with no multidrug resistance. There was no statistical difference between the risk factors evaluated. 52.1% of children received combined antibiotic treatment, the most indicated being TMS-SMX + CLI in 36 events. (38,3%). Evolution was favorable: there was no significant difference between the subgroup that isolated MRSA and the subgroup that did not isolate MRSA; 91.9% (34/37) and 92.6% (50/54) respectively (chi2: 0.01; p= 0.97 CI95: 0.26-3.88). The main etiological agent was MRSA, and treatments should be adapted to this microorganism

Humans , Male , Female , Infant, Newborn , Infant , Child, Preschool , Child , Adolescent , Skin Diseases, Infectious/microbiology , Staphylococcal Infections/microbiology , Staphylococcus aureus/isolation & purification , Soft Tissue Infections/microbiology , Skin Diseases, Infectious/drug therapy , Staphylococcus aureus/genetics , Logistic Models , Prospective Studies , Risk Factors , Soft Tissue Infections/drug therapy , Drug Therapy, Combination , Methicillin-Resistant Staphylococcus aureus/isolation & purification , Methicillin-Resistant Staphylococcus aureus/genetics , Anti-Bacterial Agents/therapeutic use
Article in Chinese | WPRIM | ID: wpr-935267


Objective: To analyze the Staphylococcal enterotoxins, Staphylococcal enterotoxin genes, drug resistance and molecular typing of 41 Staphylococcus aureus isolates from 2 food-borne illness outbreaks on 21 August and 27 September 2020 in Guangzhou. Methods: A total of 41 Staphylococcus aureus isolates from 2 outbreaks were analyzed by multilocus sequence typing (MLST) and spa typing. The Staphylococcal enterotoxins typing and the Staphylococcal enterotoxin genes of the isolates were analyzed by ELISA and PCR, respectively. The antimicrobial susceptibility of the isolates was performed by disc diffusion. 21 Staphylococcus aureus isolates were characterized using whole genome sequencing (WGS). Based on the whole genome single nucleotide polymorphism (SNP), the phylogenetic tree was constructed by Snippy. Results: 41 Staphylococcus aureus isolates were divided into 2 types by MLST and spa typing: ST6-t701 and ST7-t091. 2 ST7-t091 isolates were identified as methicillin-resistant Staphylococcus aureus (MRSA). 25 ST7-t091 isolates and 14 ST6-t701 isolates were methicillin-sensitive Staphylococcus aureus (MSSA), and were resistant to 7 and 6 antibiotics, respectively. All isolates were positive for sea by PCR. WGS revealed all 21 isolates carried scn, sak, sea, hla, hld, hlgA, hlgB, hlgC, lukD virulence genes. The results showed the isolates contained an immune evasion cluster type D which located in bacteriophage ϕSa3. The SNP phylogenetic tree showed 2 MRSA ST7-t091 were constituted a separate clade from the 12 MSSA ST7-t091 isolates and 7 ST6-t701 isolates showed high similarity to each other. Conclusion: Base on the results of phylogenetic analysis, the 2 food-borne illness outbreaks occurred on 21 August and 27 September 2020 are caused by the combination of the MRSA ST7-t091 strain and the MSSA ST7-t091 strain, and the MSSA ST6-t701 strain, respectively. All isolates have high level of antibiotic resistance and carry high virulent genes.

Humans , Anti-Bacterial Agents/pharmacology , Disease Outbreaks , Foodborne Diseases/epidemiology , Methicillin-Resistant Staphylococcus aureus/genetics , Microbial Sensitivity Tests , Multilocus Sequence Typing/methods , Phylogeny , Staphylococcal Infections/epidemiology , Staphylococcus aureus/genetics
Article in Chinese | WPRIM | ID: wpr-935306


Objectives: To analyze the causes of a foodborne outbreak in rural areas of Xinjiang between April 2 and April 5 in 2016. Methods: Cases and the relevant background information were obtained by consulting outpatient records of local health centers and regional people's hospitals and interviewing doctors and residents. All samples were collected by the laboratory test through epidemiological and food hygiene investigations. The χ2 test (Fisher's exact probability method) was used to compare differences in incidence rates. Molecular typing, virulence genes and single nucleotide polymorphisms (SNPS) were analyzed by using Pulsed Field Gel Electrophoresis (PFGE) and Whole Genome Sequencing (WGS). Results: A total of 142 cases were found in this study, with incidence rate at 5.7‰ (142/24 979). Among all cases, the main symptoms were nausea (94%), vomiting (92%) and abdominal pain (67%), and the incubation period was about 2 h (1-7.5 h). There were 16 Staphylococcus aureus isolates identified and all of them could produce A+C+E mixed enterotoxin. PFGE showed 100% homology. WGS further revealed that there were 9 and 1 strains contained by Sequence Type 1 (ST1) and ST5405, respectively. All ST1 strains were in the same clade on the genome tree. Among these, 7 strains shared close proximity (74 SNPs) and 2 strains shared close relationships as well (127 SNPs). The S. aureus isolates that caused the outbreak were introduced by a mutant isolate from the milk supply station. Conclusions: This foodborne outbreak was mainly caused by Staphylococcus aureus contamination.

Humans , Disease Outbreaks , Electrophoresis, Gel, Pulsed-Field , Foodborne Diseases/epidemiology , Staphylococcus aureus/genetics
Rev. chil. infectol ; 38(6): 774-782, dic. 2021. ilus, tab
Article in Spanish | LILACS-Express | LILACS | ID: biblio-1388320


INTRODUCCIÓN. Staphylococcus aureus es parte de la microbiota nasal en 20-30% de la población general, colonización que constituye un reservorio para su transmisión, lo que es preocupante en cepas resistentes a meticilina (SARM). OBJETIVO: Determinar la prevalencia de S. aureus en estudiantes de Medicina y Enfermería del Campus San Felipe y caracterizar sus aislamientos. MATERIAL Y MÉTODOS: El 2017 se midió la portación nasal a 225 estudiantes, a las cepas aisladas se le analizó su antibiotipo por difusión en agar, la relación clonal por electroforesis de campo pulsado y MLST. En SARM se determinó el cassette SCCmec y gen de la leucocidina de Panton-Valentine. RESULTADOS: 61 estudiantes portaron S. aureus (27,1%) incluyendo dos cepas SARM (0,9%). Staphylococcus aureus mostró resistencia a penicilina (75%), eritromicina (14%) y clindamicina (10%), cloranfenicol (1,6%) y levofloxacina, oxacilina, cefoxitina (3,3%). Se diferenciaron diecinueve pulsotipos y el secuenciotipo coincidió con complejos clonales descritos a nivel mundial en portadores de S. aureus: CC30, CC8, CC97, CC15, CC22 y CC1. Las dos cepas SARM correspondieron con los clones chileno/cordobés y USA100NY/J, ambas del CC5. CONCLUSIÓN: La portación nasal de S. aureus y SARM en los estudiantes coincidió con la portación en la población general y las cepas sensibles a meticilina mostraron diversidad clonal y alta susceptibilidad antimicrobiana, exceptuando a penicilina.

BACKGROUND: Staphylococcus aureus is part of the nasal microbiota in 20-30% of the population. This colonization is also a reservoir for its dissemination, which is worrying in the case of strains with resistance to methicillin (MRSA). AIM: To determine S. aureus nasal carriage in nursing and medical students of San Felipe Campus and characterize theirs isolates. METHODS: During 2017, nasal swabs were taken from 225 students and seeded in salt manitol agar. Antibiotypes were determined by agar diffusion and the genetic clonality was assessed by PFGE and MLST in isolated S. aureus. SCCmec cassette and Panton-Valentine leukocidin gene (pvl) presence were determined in the MRSA isolates. RESULTS: 61 students carried S. aureus (27.1%) including two MRSA strains (0.9%). S. aureus showed resistance to penicillin (75%), erythromycin (14%) and clindamycin (10%), chloramphenicol (1.6%) and levofloxacin, oxacillin, cefoxitin (3.3%). Nineteen PFGE-types were differentiated, and their sequence-types coincided with main clonal complexes described in S. aureus carriers from different places worldwide: CC30, CC8, CC97, CC15, CC22 and CC1. MRSA strains belonged to CC5 and they corresponded to the Chilean/Cordobes and USA100NY/J clones. CONCLUSION: Nasal carriage of S. aureus and MRSA in students, coincided with the general population and sensitive-methicillin strains showed clonal diversity and high antimicrobial susceptibility except for penicillin.

Humans , Staphylococcal Infections/epidemiology , Students, Nursing , Methicillin-Resistant Staphylococcus aureus/genetics , Staphylococcus aureus/genetics , Microbial Sensitivity Tests , Chile , Agar , Multilocus Sequence Typing , Genotype , Methicillin , Anti-Bacterial Agents/pharmacology
Article in English | LILACS, VETINDEX | ID: biblio-1363092


Fifty-two Staphylococcus aureus recovered from papillary ostium and milk samples collected from cows with subclinical mastitis and milking environments in three small dairy herds located in southeastern Brazil were subjected to PCR identification based on the thermonuclease (nuc) gene. All the strains were submitted to in vitro antimicrobial susceptibility testing, and we investigated the sequence types (STs), agr groups (I-IV), virulence genes encoding for Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs), biofilm-associated proteins, bi-component toxins, pyrogenic toxin superantigens, and enterotoxins. Screening for oxacillin resistance (2-6 µg/ml oxacillin), beta-lactamase activity assays, and PCR for the mecA/mecC genes detected 26 methicillin-susceptible S. aureus(MSSA) and 26 mec-independent oxacillin-nonsusceptible S. aureus (MIONSA). While MSSA isolates were found to be susceptible to all antimicrobial agents tested, or only resistant to penicillin and ampicillin, MIONSA isolates were multidrug-resistant. ST126-agr group II MSSA isolates were prevalent in milk (n=14) and carried a broad set of virulence genes (clfA, clfB, eno, fnbA, fiB, icaA, icaD, lukED, hla, and hlb), as well as the ST126-agr group II MIONSA isolated from milking liners (n=1), which also carried the eta gene. ST1-agr group III MIONSA isolates (n=4) were found in papillary ostium and milk, but most MIONSA isolates (n=21), which were identified in both papillary ostium and milking liners, were agr-negative and assigned to ST126. The agr-negative and agr group III lineages showed a low potential for virulence. Studies on the characterization of bovine-associated MSSA/MIONSA are essential to reduce S. aureus mastitis to prevent economic losses in dairy production and also to monitor the zoonotic potential of these pathogens associated with invasive infections and treatment failures in healthcare.

Cinquenta e dois isolados de Staphylococcus aureus obtidos de amostras colhidas do óstio papilar, do leite de vacas com mastite subclínica e do ambiente de ordenha em três fazendas de rebanhos leiteiros localizadas no sudeste do Brasil foram identificados por PCR para o gene da termonuclease (nuc). Todos os isolados foram testados para sensibilidade a antimicrobianos e foram investigados os sequence types (STs), grupos agr (I-IV) e genes de virulência que codificam Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs), proteínas associadas a biofilme, toxinas bi-componentes, toxinas pirogênicas com propriedades de superantígenos e enterotoxinas. Triagem para detecção de resistência à oxacilina (2-6 µg/ml oxacilina), ensaios de atividade de enzimas beta-lactamases e PCR para os genes mecA/mecC detectaram 26 estirpes de S. aureus sensíveis à meticilina (methicillin-susceptible S. aureus, MSSA) e 26 estirpes de S. aureus mec-negativas não sensíveis à meticilina (mec-independent oxacillin-nonsusceptible S. aureus, MIONSA). Enquanto os isolados MSSA foram sensíveis a todos os agentes antimicrobianos testados, ou apenas resistentes à penicilina e ampicilina, os isolados MIONSA foram multirresistentes. MSSA ST126-agr grupo II foram prevalentes no leite (n= 14) e apresentaram um amplo conjunto de genes de virulência (clfA, clfB, eno, fnbA, fiB, icaA, icaD, lukED, hla e hlb), assim como o isolado MIONSA ST126-agr grupo II proveniente de um insuflador (n= 1), o qual também apresentou o gene eta. MIONSA ST1-agr grupo III (n= 4) foram identificados no óstio papilar e leite, mas a maioria dos isolados MIONSA (n= 21), encontrados em óstios papilares e insufladores, foram agr-negativos e pertenceram ao ST126. As linhagens agr-negativas e agr grupo III apresentaram baixo potencial de virulência. Estudos sobre a caracterização de MSSA/MIONSA associados a bovinos são essenciais para a redução da mastite causada por S. aureus e de perdas econômicas na produção leiteira e, também, para o monitoramento do potencial zoonótico desses patógenos associados a infecções invasivas e falhas de tratamento em ambientes hospitalares.

Animals , Female , Cattle , Staphylococcus aureus/isolation & purification , Mastitis, Bovine/microbiology , Anti-Bacterial Agents/pharmacology , Staphylococcus aureus/drug effects , Staphylococcus aureus/genetics , Virulence , Microbial Sensitivity Tests , Polymerase Chain Reaction
Rev. argent. microbiol ; 52(3): 81-90, Sept. 2020. graf
Article in English | LILACS | ID: biblio-1340907


Abstract This study was undertaken to investígate the resistance phenotypes to macrolide-lincosamide-streptogramin B (MLSb) antibiotics and their associated genotypes in isolates of Staphylococcus aureus. We analyzed one hundred, consecutive, non-duplicate isolates (methicillin-susceptible MSSA, n = 53 and methicillin-resistant MRSA, n =47) obtained from var-ious clinical samples between July 2012 to December 2013. The resistance profile to MLSb antibiotics was determined by phenotypic methods and the resistance genes were detected by PCR assays. All of the isolates were subjected to pulsed-field gel electrophoresis (SmaI-PFGE). The overall prevalence of resistance to MLSb antibiotics was 38% and the resistance phenotype distribution was as follows: cMLSb, 22%; iMLSB, 10%; MSb, 5% and L, 1%. We detected ermA, ermC, ermB and mrsA/B genes in these resistant isolates. The single ermA gene was commonly observed mainly in those with a cMLSb R phenotype, whereas the combination ermA and ermC was more commonly observed in isolates with inducible expression. The patterns of SmaI-PFGE suggest a great genetic diversity in both MRSA and MSSA resistant to MLSb antibiotics. The results demonstrate the local presence of S. aureus resistant to MLSb antibiotics and its most frequently described responsible genes. Some of these isolates, especially those with the iMLSB phenotype, may be associated with therapeutic failure. Therefore, efforts should be directed to the correct detection of all MLSb resistant isolates using appropriate laboratory tests. PFGE results reveal a wide spread of resistance genes rather than the circulation of S. aureus clones resistant to MLSb antibiotics.

Resumen Los objetivos de este estudio fueron investigar en Staphylococcus aureus la presencia de fenotipos resistentes a los antibióticos macrólidos, lincosamidas y estreptograminas tipoB (MLSb) y conocer sus genotipos responsables. Analizamos 100 aislamientos consecutivos, no duplicados (53 sensibles a meticilina [MSSA] y 47 resistentes a meticilina [MRSA]), obtenidos entre 2012 y 2013 a partir de diferentes muestras clínicas. El perfil de resistencia a los antibióticos MLSb fue determinado por métodos fenotípicos y los genes de resistencia se detectaron por PCR. Todos los aislamientos fueron comparados por SmaI-PFGE. La prevalencia global de resistencia a los antibióticos MLSB fue del 38% y la distribución de los fenotipos de resistencia fue la siguiente: cMLSB, 22%; iMLSB, 10%; MSB, 5%; L, 1%. Se detectaron los genes ermA, ermC y mrsA/B en los aislamientos resistentes. El gen ermA se observó, sobre todo, en aislamientos con fenotipo resistente constitutivo R (cMLSB), mientras que la combinación ermA y ermC se detectó principalmente en aislamientos con resistencia inducible (iMLSB). Los patrones de Smal-PFGE sugieren una gran diversidad genética en los aislamientos resistentes a los antibióticos MLSb, tanto MRSA como MSSA. Los resultados demuestran la presencia local de S. aureus resistentes a los antibióticos MLSB y de sus genes responsables más frecuentemente descritos. Estos cultivos, especialmente aquellos con fenotipo resistente iMLSB, pueden asociarse con fallas terapéuticas. Por lo tanto, los esfuerzos deben dirigirse a la correcta detección de todos los cultivos resistentes a MLSB utilizando pruebas de laboratorio adecuadas. Los resultados de Smal-PFGE sugieren una amplia diseminación de genes de resistencia, más que la circulación de clones resistentes a los antibióticos MLSB.

Humans , Staphylococcal Infections , Drug Resistance, Multiple, Bacterial , Methicillin-Resistant Staphylococcus aureus , Phenotype , Staphylococcal Infections/epidemiology , Staphylococcus aureus/genetics , Uruguay , Microbial Sensitivity Tests , Macrolides/pharmacology , Streptogramin B/pharmacology , Drug Resistance, Multiple, Bacterial/genetics , Methicillin-Resistant Staphylococcus aureus/genetics , Lincosamides/pharmacology , Tertiary Care Centers , Genotype , Hospitals, Public , Anti-Bacterial Agents/pharmacology
Biomédica (Bogotá) ; 39(3): 513-523, jul.-set. 2019. tab, graf
Article in Spanish | LILACS | ID: biblio-1038811


Resumen Introducción. Las infecciones por Staphylococcus aureus y Staphylococcus coagulasa negativa multirresistentes a los antibióticos y asociadas con la atención en salud tienen un gran impacto epidemiológico por su alta morbimortalidad; además, se han relacionado con la formación de biopelículas, lo cual también se asocia con la resistencia a los antimicrobianos. Objetivo. Determinar la resistencia a la meticilina y cuantificar la producción de biopelículas para establecer su posible relación con los aislamientos clínicos de S. aureus y Staphylococcus coagulasa negativa. Materiales y métodos. Se estudiaron 11 cepas de S. aureus y 12 de Staphylococcus coagulasa negativa. La resistencia a la meticilina se determinó con discos de cefoxitina tomando como valores de referencia los estándares del Clinical Laboratory Standards Institute (CLSI) de 2018. La producción de biopelícula se cuantificó con cristal violeta. Los genes mecA e icaADBC se identificaron mediante reacción en cadena de la polimerasa (PCR), y se hizo un análisis bivariado con la prueba de ji al cuadrado y el coeficiente V de Cramér, utilizando el programa SPSS™, versión 20.0. Resultados. Nueve cepas de S. aureus fueron resistentes a la meticilina (SARM) y dos fueron sensibles. Ocho cepas de Staphylococcus coagulasa negativa fueron resistentes y cuatro fueron sensibles. El genotipo mecA se encontró en ocho de las nueve cepas de S. aureus y en seis de las ocho de Staphylococcus coagulasa negativa resistentes a meticilina. Todas las cepas formaron biopelícula. Diez cepas de S. aureus y 11 de Staphylococcus coagulasa negativa presentaron el genotipo icaADCB. No se encontró asociación entre la resistencia a meticilina y la formación de biopelícula. Conclusiones. La cefoxitina es suficiente para determinar el fenotipo resistente a meticilina y se asoció con el genotipo mecA. Las cepas resistentes a la meticilina y poseedoras del gen mecA pueden presentar un mecanismo de resistencia alterno. Los dos grupos de cepas formadoras de biopelícula se relacionaron con la presencia del operón icaADCB. La formación de biopelícula y la resistencia a la meticilina se expresaron como características independientes en los dos grupos de cepas.

Abstract Introduction: Infections associated with health care caused by S. aureus and coagulase- negative Staphylococci multi-resistant to antibiotics cause a high epidemiological impact due to their high morbidity and mortality. Biofilm formation, which has been associated with antimicrobial resistance, can also occur. Objectives: To determine methicillin resistance and to quantify the biofilm production to establish if there is a relationship in clinical isolates of S. aureus and coagulase-negative Staphylococci. Material and methods: A total of 11 strains of S. aureus and 12 of coagulase-negative Staphylococci were studied. Methicillin resistance was determined with cefoxitin discs and the Clinical Laboratory Standards Institute (CSLI), 2018 reference values. Biofilm production was quantified by the crystal violet method. The mecA and icaADBC genes were identified by PCR. A bivariate analysis was performed with chi-square (c2) and Cramér's V statistical tests, using SPSS™, version 20.0 software. Results: Nine S. aureus strains were methicillin-resistant and two were sensitive. Eight coagulase-negative Staphylococci strains were resistant and four were sensitive. The mecA genotype was found in eight of the nine S. aureus resistant strains and six of eight resistant coagulase-negative Staphylococci. All strains formed biofilms. Ten strains of S. aureus and 11 of coagulase-negative Staphylococci presented the icaADCB genotype. No association was found between methicillin-resistance and biofilm formation. Conclusions: Cefoxitin is enough to define the resistance phenotype and is associated with the mecA genotype. All strains formed biofilms and were related to the presence of the icaADCB operon. Biofilm formation and methicillin resistance were independent features in both groups of strains.

Humans , Staphylococcus/drug effects , Staphylococcus/physiology , Staphylococcus aureus/drug effects , Staphylococcus aureus/physiology , Methicillin Resistance , Biofilms/growth & development , Oxacillin/pharmacology , Staphylococcal Infections/microbiology , Staphylococcus/enzymology , Staphylococcus/genetics , Staphylococcus aureus/genetics , Bacterial Proteins/genetics , DNA, Bacterial/isolation & purification , Microbial Sensitivity Tests/methods , Cefoxitin/pharmacology , Methicillin Resistance/genetics , Coagulase , Penicillin-Binding Proteins/genetics , Methicillin-Resistant Staphylococcus aureus/drug effects , Methicillin-Resistant Staphylococcus aureus/genetics , Genes, Bacterial , Mexico , Anti-Bacterial Agents/pharmacology
Braz. j. infect. dis ; 23(1): 8-14, Jan.-Feb. 2019. tab, graf
Article in English | LILACS | ID: biblio-1001504


ABSTRACT Introduction: Bacterial tonsillitis is an upper respiratory tract infection that occurs primarily in children and adolescents. Staphylococcus aureus is one of the most frequent pathogens in the etiology of tonsillitis and its relevance is due to its antimicrobial resistance and persistence in the internal tissues of the tonsils. Tonsillectomy is indicated in cases of recurrent tonsillitis after several failures of antibiotic therapy. Material and methods: In this study we evaluated 123 surgically removed tonsils from patients who had history of recurrent tonsillitis. The tonsils were submitted to microbiological analysis for detection of S. aureus. The isolates were identified by PCR for femA gene. Antimicrobial susceptibility of the isolates was determined by disk diffusion tests. All isolates were submitted to PCR to detect mecA and Panton-Valentine leucocidin (PVL) genes. The genetic similarity among all isolates was determined by pulsed field gel electrophoresis. Results: Sixty-one S. aureus isolates were obtained from 50 patients (40.7%) with mean age of 11.7 years. The isolates showed high level resistance to penicillin (83.6%), 9.8% had inducible MLSb phenotype, and 18.0% were considered multidrug resistant (MDR). mecA gene was detected in two isolates and the gene coding for PVL was identified in one isolate. The genetic similarity analysis showed high diversity among the isolates. More than one genetically different isolate was identified from the same patient, and identical isolates were obtained from different patients. Conclusions: MDR isolates colonizing tonsils even without infection, demonstrate persistence of the bacterium and possibility of antimicrobial resistance dissemination and recurrence of infection. A specific clone in patients colonized by S. aureus was not demonstrated.

Humans , Male , Female , Infant , Child, Preschool , Child , Adolescent , Adult , Middle Aged , Young Adult , Staphylococcal Infections/microbiology , Staphylococcus aureus/isolation & purification , Staphylococcus aureus/genetics , Tonsillitis/microbiology , Staphylococcus aureus/drug effects , Tonsillectomy/methods , Tonsillitis/surgery , Polymerase Chain Reaction , Cross-Sectional Studies , Electrophoresis, Gel, Pulsed-Field , Drug Resistance, Multiple, Bacterial/drug effects , Methicillin-Resistant Staphylococcus aureus/isolation & purification , Methicillin-Resistant Staphylococcus aureus/drug effects , Anti-Bacterial Agents/pharmacology
Rev. Soc. Bras. Med. Trop ; 52: e20190095, 2019. tab, graf
Article in English | LILACS | ID: biblio-1013299


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.

Humans , Staphylococcus aureus/drug effects , Staphylococcus aureus/genetics , Methicillin Resistance , Virulence Factors/genetics , Methicillin-Resistant Staphylococcus aureus/genetics , Anti-Bacterial Agents/pharmacology , Staphylococcal Infections/epidemiology , Staphylococcus aureus/isolation & purification , Staphylococcus aureus/classification , Virulence/genetics , Brazil/epidemiology , Microbial Sensitivity Tests , Molecular Epidemiology , Tertiary Care Centers , Hospitals, Public
Pesqui. vet. bras ; 38(11): 2029-2036, Nov. 2018. tab, ilus
Article in English | LILACS, VETINDEX | ID: biblio-976405


The present study determined the frequency of Staphylococcus aureus virulence genes in 2,253 milk samples of cows (n=1000) and goats (n=1253) raised in three different geographical regions of the state Pernambuco, Brazil. The presence of genes of virulence factors associated to adhesion to host cells (fnbA, fnbB, clfA and clfB), toxinosis (sea, seb, sec, sed, seg, seh, sei, tsst, hla and hlb), and capsular polysaccharide (cap5 and cap8) was evaluated by PCR. A total of 123 and 27 S. aureus strains were isolated from cows' and goats' milk, respectively. The sec and tsst genes were detected exclusively in goats' isolates, while the seh gene was only identified in cows' isolates. The number of toxin genes per strain showed that goats' isolates are likely more toxic than bovines' isolates. The cap5 genotype predominated in both host species, especially in strains collected from cows raised in the Agreste region. The cap8 genotype is likely more virulent due to the number of virulence genes per strain. The results of the present study demonstrate that S. aureus may pose a potential threat to human health in Brazil, and, therefore, these results should support actions related to mastitis control programs.(AU)

O presente estudo determinou a frequência de genes de virulência de Staphylococcus aureus em 2253 amostras de leite, sendo de vacas n=1000 e de cabras n=1253, procedentes das três regiões geográficas do estado de Pernambuco, Brasil. A presença de genes de fatores de virulência associados à adesão às células hospedeiras (fnbA, fnbB, clfA e clfB), toxinosis (sea, seb, sec, sed, seg, seh, sei, tsst, hla e hlb) e polissacarídeo capsular (cap5 e cap8) foram avaliadas por PCR. Um total de 123 e 27 cepas de S. aureus foram isoladas do leite de vacas e cabras, respectivamente. Os genes sec e tsst foram detectados exclusivamente em isolados de cabras, enquanto o gene seh foi identificado apenas em isolados de vaca. O número de genes de toxina por cepa mostrou que os isolados de cabras são potencialmente mais tóxicos do que os isolados obtidos de bovinos. O genótipo cap5 predominou em ambas as espécies hospedeiras, especialmente em cepas coletadas de vacas criadas na região Agreste. O genótipo cap8 é potencialmente mais virulento devido ao número de genes de virulência por isolado. Os resultados do presente estudo demonstram que S. aureus pode representar uma ameaça potencial para a saúde humana no Brasil e, portanto, estes resultados devem subsidiar ações relacionadas aos programas de controle de mastite.(AU)

Animals , Female , Cattle , Staphylococcus aureus/genetics , Cattle/microbiology , Goats/microbiology , Mastitis/microbiology , Mastitis/epidemiology , Mastitis, Bovine/microbiology , Mastitis, Bovine/epidemiology , Virulence , Dairying , Milk/microbiology
Braz. j. infect. dis ; 22(6): 487-494, Nov.-Dec. 2018. tab, graf
Article in English | LILACS | ID: biblio-984020


ABSTRACT Background: The rate of methicillin-resistant Staphylococcus aureus (MRSA) among the total of S. aureus isolates decreased to 35.3% in 2017 in China. It is unclear whether the molecular characteristics of S. aureus isolates have changed as the rate decreased. Objective: This study aimed to investigate the molecular characteristics and virulence genes profile of S. aureus isolates causing bloodstream infection and analyze the correlation between the prevalence rates of the common sequence types and MRSA. Methods: A total of 112 S. aureus strains from eight hospitals of four cities, including 32 MRSA isolates, were identified and evaluated through multilocus sequence typing, spa typing, and determination of virulence genes. Results: Twenty-five STs were identified, of which ST5 (21.4%) was the most prevalent, whereas the prevalence of ST239 correlated with the rate of MRSA among all S. aureus isolates. Forty-six spa types were identified, of which t2460 (14.3%) was the most common. clfa, hla, seb, fnbA and hlb were the prevailing virulence genes. 81.3% MRSA and 45.0% methicillin-sensitive S. aureus (MSSA) isolates harbored six or more tested virulence genes. ST5-t2460, seldom noted in bloodborne S. aureus isolates in China, was the most common clone. The prevalence of harboring six or more virulence genes in ST5-t2460 and ST188-t189 were 93.8% and 8.3%, respectively. Conclusion: ST5-t2460 was the most common clone in S. aureus causing bloodstream infection followed by ST188-t189, which had never been noted in China before. Moreover, ST5-t2460 harbored more virulence genes than ST188-t189, and the prevalence of ST239 clone decreased with the proportion of MRSA among all S. aureus isolates.

Humans , Staphylococcus aureus/genetics , Staphylococcus aureus/pathogenicity , Virulence/genetics , Bacteremia/virology , Phenotype , Microbial Sensitivity Tests , Virulence Factors/genetics , Methicillin-Resistant Staphylococcus aureus/genetics , Methicillin-Resistant Staphylococcus aureus/pathogenicity , Molecular Typing , Multilocus Sequence Typing , Genotype
Rev. Soc. Bras. Med. Trop ; 51(4): 528-532, July-Aug. 2018. tab, graf
Article in English | LILACS | ID: biblio-1041475


Abstract INTRODUCTION Molecular techniques for the detection of pathogens have been shown to be effective diagnostic tools with high sensitivity and short turnaround times. METHODS This study compared five Staphylococcus aureus DNA extraction methods for detection by the polymerase chain reaction. RESULTS: The concentration and purity of the extracted DNA showed that the methods did not yield DNA of significant quality. However, most protocols yielded 100% positivity, even with low DNA concentrations. CONCLUSIONS: Although one protocol seemed more efficient than the others, PCR was sensitive enough to allow for detection of S. aureus with all the protocols.

Staphylococcus aureus/genetics , DNA, Bacterial/isolation & purification , Polymerase Chain Reaction/methods , Bacteriological Techniques/methods , DNA, Bacterial/genetics , Sensitivity and Specificity
Biomédica (Bogotá) ; 38(1): 96-104, ene.-mar. 2018. tab
Article in Spanish | LILACS | ID: biblio-888552


Resumen Introducción. Staphylococcus aureus coloniza mucosas y piel, y causa graves infecciones en el hombre y los animales. Es importante establecer el estatus de portadoras de cepas enterotoxigénicas de este microorganismo en manipuladoras de alimentos, con el fin de prevenir intoxicaciones alimentarias. Objetivo. Establecer las correlaciones entre los genes de enterotoxinas clásicas, el gen tsst-1, la producción de toxinas en cultivo y la resistencia antimicrobiana en aislamientos de S. aureus provenientes de manipuladoras de alimentos que cuidan niños en sus comunidades. Materiales y métodos. Se cultivaron muestras de las fosas nasales y las yemas de los dedos de las manos, y se identificó S. aureus empleando las pruebas de rutina y métodos automatizados. La extracción de ADN se hizo mediante el método de bromuro de cetil-trimetil-amonio (Cetyl-Trimethyl- Ammonium Bromide, CTAB) modificado. Para la detección de superantígenos se emplearon pruebas de reacción en cadena de la polimerasa (PCR) simple y múltiple, y para la de toxinas, estuches comerciales. Resultados. Se encontró que el 22,0 % de los aislamientos correspondía a portadoras de S. aureus: 17,0 % en los aislamientos de fosas nasales; 5,0 % en los de las manos y 6,7 % simultáneamente en los dos sitios. La prevalencia de superantígenos fue de 73,7 %. El genotipo más frecuente fue el sea-tsst-1, con 10,0 %. La resistencia a un solo antibiótico fue de 74,7 % y, a cuatro antibióticos, de 3,2 %; de los aislamientos, el 93,7 % correspondía a cepas productoras de betalactamasas. La detección de genes clásicos y de tsst-1 mediante PCR fue de 48,4 % y la de toxinas en el sobrenadante, de 42,1 %, con una correlación de 95,7 %. Las mayores correlaciones se establecieron entre las toxinas TSST-1 (22/22) y SEA (17/18). La correlación del gen tsst-1 con la proteína y la resistencia fue de 100 %. Todos los aislamientos con el genotipo sea-tsst-1 t fueron resistentes y productores de las toxinas. Conclusión. La tasa de aislamientos de S. aureus toxigénicos y resistentes obtenidos de mujeres que cuidan y preparan alimentos para niños fue de más de 70 %, lo que demostró su gran virulencia y la consecuente necesidad de aplicar estrictamente las normas higiénicas y sanitarias vigentes para evitar el riesgo de intoxicación alimentaria.

Abstract Introduction: Staphylococcus aureus colonizes mucous membranes and skin causing severe infections in humans and animals. It is important to determine carrier status of enterotoxigenic strains of this microorganism in food handlers to prevent food poisoning. Objective: To establish the correlations among classic enterotoxigenic genes, tsst-1 gene, the production of toxins in cultures and antimicrobial resistance in S. aureus isolates from women who handle the food, feed and take care of children in their communities. Materials and methods: Nasal swab and finger samples were cultured and S. aureus was identified using routine methods and automated systems. DNA extraction was done by the CTAB modified method, and superantigen detection by simple and multiplex PCR, while toxins were detected using commercial kits. Results: We found that 22.0% of subjects were S. aureus carriers: 17.0% corresponded to nose samples, 5.0% to hands and 6.7% to both nose and hands. The prevalence of superantigens was 73.7%. The most frequent genotype was sea-tsst-1 with 10%. Resistance to one antibiotic was 74.7%, and to four antibiotics, 3.2%; 93.7% of the isolates were betalactamase-positive. Classical genes and tsst-1 gene were detected by PCR in 48.4% of samples and toxins in supernatant were detected in 42.1% of them with 95.7% of correlation.The highest correlations were established for TSST-1 and SEA with 100% and 94.4%, respectively. The correlation of tsst-1 gene with toxin production and resistance was 100%. All isolates with genotype sea-tsst-1 were toxin-positive and resistant. Conclusion: The rate of toxigenic and resistant S. aureus isolates from women in charge of feeding and taking care of children was higher than 70%, which demonstrates its high virulence. This requires the strict application of hygienic and sanitary regulations in order to avoid the risk of food poisoning.

Adult , Child , Female , Humans , Staphylococcal Infections/microbiology , Staphylococcus aureus/isolation & purification , Carrier State/microbiology , Child Care , Superantigens/analysis , Drug Resistance, Multiple, Bacterial , Enterotoxins/immunology , Antigens, Bacterial/analysis , Staphylococcal Infections/transmission , Staphylococcal Infections/epidemiology , Staphylococcus aureus/drug effects , Staphylococcus aureus/genetics , Staphylococcus aureus/immunology , Carrier State/epidemiology , Prevalence , Superantigens/genetics , Fingers/microbiology , Food Handling , Genes, Bacterial , Genotype , Nasal Cavity/microbiology , Antigens, Bacterial/genetics
J. appl. oral sci ; 26: e20170141, 2018. graf
Article in English | LILACS, BBO | ID: biblio-893685


Abstract Objective Staphylococcus aureus strains can be disseminated during dental treatments and occasionally lead to the contamination and infection of patients and dentists, which is an important public health problem. The dynamics of the airborne propagation and the genetic diversity of S. aureus isolated in an academic dental clinic environment were investigated using isoenzyme typing. Material and Methods The isoenzymes of 44 previously reported isolates were obtained from fresh cultures and extracted using glass beads. Nine isoenzymes were investigated using multilocus enzyme electrophoresis (MLEE). The genetic diversity and relationship among the strains (electrophoretic type - ET) were determined using statistics previously described by Nei25 (1972) and the SAHN grouping method (UPGMA algorithm). Results Clonal pattern analyses indicated a high level of genetic polymorphism occurring among the 33 ETs, which were grouped into five taxa. Each taxon presented one or more clusters that were moderately related and that contained two or more identical/highly related isolates, revealing seasonal airborne propagation in these dental clinic environments. Conclusions These data suggest the occurrence of active microevolutionary processes in S. aureus as well as the possibility of environmental propagation during a 14-month time span. Such findings are important to show that multiuser academic dental clinics can retain certain strains that are spreadable to different niches.

Seasons , Staphylococcus aureus/isolation & purification , Staphylococcus aureus/genetics , Dental Clinics/statistics & numerical data , Polymorphism, Genetic , Reference Values , Staphylococcal Infections/microbiology , Staphylococcus aureus/enzymology , Time Factors , Genetic Variation , Cluster Analysis , Cross Infection/microbiology , Equipment Contamination , Bacterial Typing Techniques/methods , Multilocus Sequence Typing/methods , Isoenzymes/isolation & purification
Arq. bras. med. vet. zootec. (Online) ; 69(4): 843-850, jul.-ago. 2017. tab
Article in English | LILACS, VETINDEX | ID: biblio-876602


This study aims to detect the main virulence and antimicrobial resistance genes in Stapylococcus aureus from bovine mastitic milk as well as classifying them according to agr typing. A total of 55 strains from six dairy unities in the state of Rio de Janeiro were selected, of these 27.3% presented fbnA and 78,2% for fbnB genes, respectively. None of the strains tested were positive for cap5 gene, 3.6% were positive for cap8 gene. Additionally, 94.5% of strains had hlA gene and 89.1% had hlB gene while 67.3% of the strains had icaA gene and 87.3% had icaD gene. From these results it was possible to establish 12 different virulence profiles. Prevalence of agrII type was detected in 81.8% of the isolates. Concerning antimicrobial resistance evaluation, the studied strains were susceptible to all antibiotics tested except penicillin, 83.6% being resistant strains. None of the strains had mecA gene, however, 40% of the strains had blaZ gene. Associating virulence and resistance data made it possible to obtain 23 different profiles. This great diversity of strains shows wide array of bacterial strategies and the challenge of mastitis prevention in cattle. Despite antimicrobial susceptibility, these strains presented certain genes that allow its persistence in the herd.(AU)

O presente estudo teve como objetivo detectar os principais genes de virulência e resistência antimicrobiana em Staphylococcus aureus oriundos de leite bovino mastítico e classificá-los de acordo com a tipagem do gene agr. Foram selecionados 55 isolados de seis unidades produtores no estado do Rio de Janeiro. Destas, o gene fbnA foi encontrado em 27,3% das cepas e 78,2% possuíam o gene fbnB. Em nenhuma cepa foi encontrado o gene cap5 e 3,6% possuíam o gene cap8. O gene hlA foi encontrado em 94,5% das cepas e 89,1% possuíam o gene hlB. O gene icaA foi encontrado em 67,3% das cepas e 87,3% possuíam o gene icaD. Com base nesses resultados, foi possível estabelecer 12 diferentes perfis de virulência. Prevalência do agr tipo II foi detectada em 81,8% dos isolados. Considerando-se a avaliação da resistência antimicrobiana, as cepas estudadas foram suscetíveis a todos os antibióticos exceto penicilina, sendo detectado um percentual de 83,6% de cepas resistentes. Nenhuma das cepas apresentou o gene mecA, contudo 40% das cepas apresentaram o gene blaZ. Vinte e três perfis diferentes foram estabelecidos por associação de dados de virulência e resistência. Essa grande diversidade de cepas mostra a ampla gama de estratégias bacterianas e o desafio da prevenção à mastite no gado bovino, considerando-se que, a despeito da suscetibilidade antimicrobiana, essas cepas apresentam genes que permitem sua persistência no rebanho.(AU)

Drug Resistance, Microbial , Staphylococcus aureus/genetics , Staphylococcus aureus/virology , Virulence , Anti-Bacterial Agents , Cattle , Mastitis, Bovine , Milk
Pesqui. vet. bras ; 37(7): 691-696, jul. 2017. tab, ilus, mapas
Article in Portuguese | LILACS, VETINDEX | ID: biblio-895474


A capacidade de produção de toxinas pelo Staphylococcus aureus no leite e produtos derivados está relacionado com surtos de intoxicação alimentar. Objetivou-se nesta pesquisa, estudar a ocorrência de genes que codificam para enterotoxinas estafilocócicas (sea, seb, sed, seg, seh e sei) e toxinas α e ß hemolítica (hla e hlb) em S. aureus isolados de 53 amostras de leite de tanques expansão comunitários no Estado de Alagoas, Brasil. Foram identificados 27 isolados (50,94%) como S. aureus pela amplificação do gene nuc. 13/27 isolados (48,1%) foram positivos para pelo menos um gene das enterotoxinas estudadas, sendo as frequências dos genes sea 33,3%, seh 18,5%, sei 11,1% e sed 7,4%; não entanto não foram identificados os genes seb e seg nestas bactérias. Para as toxinas hemolíticas, 51,9% dos isolados portavam ambos genes (hla e hlb), sendo a frequência para o gene hla de 81,5% e para o gene hlb de 51,9%. A frequência de genes das toxinas avaliadas é alta o que constitui um risco potencial para a saúde pública em especial, as enterotoxinas por serem termoestáveis e estarem asssociados com surtos de intoxicação alimentar.(AU)

The capacity of toxin production by Staphylococcus aureus in milk and dairy products is associated with food poisoning outbreaks. The objective of this research was to study the frequency of genes encoding staphylococcal enterotoxin (sea, seb, sed, seg, seh and sei) and α and ß hemolytic toxins (hla and hlb) in S. aureus isolates from 53 milk samples from community tanks in the State of Alagoas, Brazil. Twenty-seven isolates (50.94%) were identified as S. aureus by nuc gene amplification; 13/27 isolates (48.1%) were positive for at least one gene of the studied enterotoxins and the frequency of genes sea was 33.3%, seh 18.5%, sei 11.1% and sed 7.4%; the seb and sec genes have not been identified in the bacteria. For the hemolytic toxins, 51.9% of isolates harbored both genes (hla and hlb), the frequency of hla gene was 81.5% and 51.9% for the hlb gene. The evaluated toxin-encoding gene frequency is high and constitutes a potential risk for public health, especially staphylococcal enterotoxin genes; because they are heat-stable enterotoxins and have been associated with food poisoning.(AU)

Staphylococcus aureus/genetics , Superantigens/genetics , Milk/microbiology , Enterotoxins , Polymerase Chain Reaction/veterinary
Mem. Inst. Oswaldo Cruz ; 112(7): 499-503, July 2017. graf
Article in English | LILACS | ID: biblio-1040573


ABSTRACT Staphylococcus aureus pandemic clone USA300 has, in addition to its constitutive arginine catabolism (arc) gene cluster, an arginine catabolism mobile element (ACME) carrying another such cluster, which gives this clone advantages in colonisation and infection. Gene arcR, which encodes an oxygen-sensitive transcriptional regulator, is inside ACME and downstream of the constitutive arc gene cluster, and this situation may have an impact on its activation. Different relative expression behaviours are proven here for arcRACME and the arcACME operon compared to the constitutive ones. We also show that the artificially expressed recombinant ArcRACME protein binds to the promoter region of the arcACME operon; this mechanism can be related to a positive feedback model, which may be responsible for increased anaerobic survival of the USA300 clone during infection-related processes.

Humans , Operon/genetics , Arginine/genetics , Staphylococcus aureus/genetics , Bacterial Proteins/genetics , DNA-Binding Proteins/genetics , Arginine/metabolism , Staphylococcus aureus/metabolism , Gene Expression Regulation, Bacterial/genetics , Interspersed Repetitive Sequences/genetics , Genes, Bacterial/genetics
Arch. argent. pediatr ; 115(3): 274-277, jun. 2017.
Article in English, Spanish | LILACS, BINACIS | ID: biblio-1038370


Antecedentes/Objetivo. Describir el perfil epidemiológico de la portación nasal de cepas de Staphylococcus aureus (S. aureus), su resistencia a antibióticos y la presencia de los genes de leucocidina de Panton-Valentine (LPV) y mecA en niños en edad escolar que viven en zonas de gran altitud del sudoeste de China. Métodos. En el estudio transversal, se analizaron hisopados nasales de estudiantes a fin de detectar S. aureus. Se realizó la prueba de la reacción en cadena de la polimerasa (RCP) para identificar los genes de LPV y mecA. Resultados. Del total de 314 niños, se detectó S. aureus en el 5,10% (16/314). La resistencia de las cepas aisladas a la penicilina, eritromicina, clindamicina, rifampicina y cefoxitina fue del 100%, 81,3%, 81,3%, 0,0% y 6,3%, respectivamente. Ninguna de las cepas mostró resistencia a la vancomicina. Se detectó la expresión del gen mecA en 3 cepas aisladas, y 10 cepas aisladas dieron resultado positivo para el gen de LPV. Conclusión. Se detectó S. Aureus en el 5,10% (16/314) de la población del estudio; el 0,96% (3 /314) presentó S. Aureus resistente a la meticilina (SARM). Además, se detectó la expresión de los genes de LPV y mecA en 10 y 3 cepas aisladas, respectivamente.

Background/Aim. To describe the epidemiological profile of nasal carriage of Staphylococcus aureus (S. aureus) strains, its antibiotic resistance and mecA and Panton Valentine leukocidin (PVL) genes presence, in school children residing in high altitude areas of Southwestern China. Methods. The cross sectional study screened nasal swabs taken from students for S. aureus. PCR was performed to identify mecA and PVL genes. Results. Of the total 314 children 5.10% (16/314) was detected S. aureus. The resistance of isolated strains to penicillin, erythromycin, clindamycin, rifampicin and cefoxitin was 100%, 81.3%, 81.3%, 0.0%, and 6.3% respectively. No strains demonstrated resistance to vancomycin; expression of mecA gene was detected in 3 isolates and 10 isolates were PVL-positive. Conclusion. S. aureus was detected in 5.10% (16/314) of the study population; 0.96% (3/314) had methicillin resistant S. aureus (MRSA); expression of the mecA and PVL genes were detected in 3 and 10 isolates respectively.

Humans , Male , Female , Child , Staphylococcus aureus/drug effects , Carrier State/microbiology , Nose/microbiology , Altitude , Staphylococcus aureus/isolation & purification , Staphylococcus aureus/genetics , Bacterial Proteins/genetics , Bacterial Toxins/genetics , China , Cross-Sectional Studies , Drug Resistance, Bacterial , Penicillin-Binding Proteins/genetics , Exotoxins/genetics , Leukocidins/genetics
Braz. J. Vet. Res. Anim. Sci. (Online) ; 54(2): 117-128, 2017. tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-875078


Staphylococcus aureus is one of the most common microorganisms responsible for high morbidity and mortality in humans and animals. Methicillin-resistant S. aureus are responsible for several outbreaks worldwide and therapeutic arsenal has become scarce. The present investigation verified the epidemiological profile of S. aureus strains isolated from the veterinary hospital staff, from dairy cattle workers and also from milk samples of dairy cattle presenting mastitis. Samples were characterized phenotypically by antibiogram, catalase, and coagulase tests, and also by Voges-Proskauer test. The isolated strains were characterized genotypically by specific Polymerase Chain Reaction and Amplified Ribosomal DNA Restriction Analysis (ARDRA). From the 218 isolated strains, 27 were identified as S. aureus (12%), four of them were resistant to oxacillin and two of them were classified as MRSA (Methicillin-resistant S. aureus). The prevalence of isolated strains among animal personnel care was low (2%) but all MRSA isolates were found among the clinical staff. Results of ARDRA pointed out that S. aureus strains isolated from different animal care personnel were grouped in the same cluster when HindIII and HinfII restriction enzymes were used. When ARDRA was performed with HaeIII enzyme, the formation of two clusters was observed, but the isolated strains were not correlated. The prevalence of S. aureus strains isolated was higher in clinical staff and the biochemical and molecular assays of them presented 100% of correlation.(AU)

Staphylococcus aureus está entre os microrganismos que apresentam as maiores taxas de morbidade e mortalidade em seres humanos e animais. Linhagens de S. aureus resistentes a meticilina podem causar surtos de infecção em todo o mundo, o que contribui para a escassez de arsenal terapêutico. Este trabalho analisou o perfil epidemiológico de estirpes de S. aureus isoladas de pessoas que trabalham em contato com animais em um hospital veterinário com gado leiteiro e também em amostras de leite de vacas acometidas por mastite. As estirpes de S. aureus isoladas foram caracterizadas fenotipicamente por meio de antibiograma, testes de catalase e coagulase, e pelo teste de Voges-Proskauer. As amostras também foram caracterizadas genotipicamente pela técnica de Análise de Restrição de DNA Ribossômico Amplificado (ARDRA-PCR). Das 218 estirpes isoladas, 27 foram identificadas como S. aureus (12%). Entre essas, quatro estirpes foram resistentes à oxacilina e duas classificadas como SARM (S. aureus resistente à meticilina). A ocorrência de estirpes de S.aureus isoladas entre o pessoal que trabalha em contato com os animais foi baixa (2%), mas estirpes identificadas como SARM foram encontradas na equipe clínica. As análises de ARDRA realizadas com as enzimas de restrição HindIII e HinfII demonstraram que S. aureus isolados de diferentes indivíduos que trabalhavam com animais foram agrupados no mesmo cluster. Quando a ARDRA foi realizada com HaeIII foi observada formação de dois grupos, mas os isolados não se correlacionaram. Conclusão: a ocorrência de estirpes de S. aureus isoladas foi maior na equipe clínica, apresentando também correlação de 100% nos ensaios bioquímicos e moleculares.(AU)

Animals , Cattle , Animal Technicians , Methicillin-Resistant Staphylococcus aureus/isolation & purification , Milk/microbiology , Staphylococcus aureus/genetics , Staphylococcus aureus/isolation & purification , Mastitis, Bovine , Microbial Sensitivity Tests/veterinary , Polymerase Chain Reaction/methods