Population structure of food-borne Staphylococcus aureus in China / 中华流行病学杂志

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.

Características clínicas y microbiológicas de infecciones de piel y partes blandas en pacientes pediátricos de dos hospitales de Buenos Aires / Skin and soft tissue infections in pediatrics

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

Genomic characterization, antimicrobial resistance profiles, enterotoxin, and biofilm production of methicillin-resistant Staphylococcus aureus isolated from clinical and animal products origins in Eastern Turkey / Caracterização genômica perfis de resistência antimicrobiana, produção de enterotoxinas e biofilme Staphylococcus aureus resistente à meticilina isolado de origem clínica e de produtos de origem animal no leste da Turquia

Staphylococcus aureus is an opportunistic and ubiquitous pathogen found in the skin, nares, and mucosal membranes of mammals. Increasing resistance to antimicrobials including methicillin has become an important public concern. One hundred and eight (108) S. aureus strains isolated from a total of 572 clinical and animal products samples, were investigated for their biofilm capability, methicillin resistance, enterotoxin genes, and genetic diversity. Although only one strain isolated from raw retail was found as a strong biofilm producer, the percentage of antimicrobial resistance pattern was relatively higher. 17.59% of S. aureus strains tested in this study were resistant to cefoxitin and identified as methicillin-resistant S. aureus (MRSA) isolates. mecA and mecC harboring S. aureus strains were detected at a rate of 2.79% and 0.93%, respectively. In addition, staphylococcal enterotoxin genes including Sea, Seb, Sec, and Sed genes were found to be 18.5%, 32.4%, 6.5% and 3.7%, respectively. The phylogenetic relationship among the isolates showed relationship between joint calf and cow milk isolates. Multi locus sequence typing (MLST) revealed three different sequence types (STs) including ST84, ST829, and ST6238. These findings highlight the development and spread of MRSA strains with zoonotic potential in animals and the food chain throughout the world.

Staphylococcus aureus é um patógeno dúctil e ubíquo encontrado na pele, narinas e membranas mucosas de mamíferos. O aumento da resistência aos antimicrobianos, incluindo a meticilina, tornou-se uma importante preocupação pública. Cento e oito (108) cepas de S. aureus isoladas de um total de 572 amostras clínicas e de produtos animais foram investigadas por sua capacidade de biofilme, resistência à meticilina, genes de enterotoxinas e diversidade genética. Embora apenas uma cepa isolada do cru tenha sido encontrada como forte produtora de biofilme, a porcentagem do padrão de resistência antimicrobiana foi relativamente maior. Parte das cepas (17,59%) de S. aureus testadas neste estudo eram resistentes à cefoxitina e identificadas como isolados de MRSA. mecA e mecC abrigando cepas de S. aureus foram detectados a uma taxa de 2,79% e 0,93%, respectivamente. Além disso, verificou-se que os genes da enterotoxina estafilocócica, incluindo os genes Sea, Seb, Sec e Sed, eram 18,5%, 32,4%, 6,5% e 3,7%, respectivamente. A relação filogenética entre os isolados mostrou relação entre os isolados de bezerro e leite de vaca. A tipagem de sequência multiloco (MLST) revelou três tipos de sequência diferentes (STs), incluindo ST84, ST829 e ST6238. Essas descobertas destacam o desenvolvimento e a disseminação de cepas de MRSA com potencial zoonótico em animais e na cadeia alimentar em todo o mundo.

Analysis of genomic information and biological characteristics of a bacteriophage against methicillin-resistant Staphylococcus aureus in patients with median sternal incision infection / 中华烧伤杂志

Objective: To isolate and purify a bacteriophage against methicillin-resistant Staphylococcus aureus (MRSA), and to analyze its genomic information and biological characteristics. Methods: The experimental research methods were adopted. MRSA (hereinafter referred to as host bacteria) solution was collected from the wound of a 63-year-old female patient with the median sternum incision infection admitted to the Second Affiliated Hospital of Army Medical University (the Third Military Medical University). The bacteriophage, named bacteriophage SAP23 was isolated and purified from the sewage of the Hospital by sewage co-culture method and double-layer agar plate method, and the plaque morphology was observed. The morphology of bacteriophage SAP23 was observed by transmission electron microscope after phosphotungstic acid negative staining. The whole genome of bacteriophage SAP23 was sequenced with NovaSeq PE15 platform after its DNA was prepared by sodium dodecyl sulfonate/protease cleavage scheme, and genomic analysis including sequence assembly, annotation, and phylogenetic tree were completed. The bacteriophage SAP23 solution was co-incubated with the host bacterial solution for 4 h at the multiplicity of infection (MOI) of 10.000 0, 1.000 0, 0.100 0, 0.010 0, 0.001 0, and 0.000 1, respectively, and then the bacteriophage titer was measured by the drip plate method to select the optimal MOI, with here and the following sample numbers of 3. The bacteriophage SAP23 solution was co-incubated with the host bacterial solution at the optimal MOI for 5, 10, and 15 min, respectively, and the bacteriophage titer was measured by the same method as mentioned above to select the optimal adsorption time. After the bacteriophage SAP23 solution was co-incubated with the host bacterial solution at the optimal MOI for the optimal adsorption time, the bacteriophage titers were measured by the same method as mentioned above at 0 (immediately), 5, 10, 15, 20, 30, 40, 50, 60, 80, 100, and 120 min after culture, respectively, and a one-step growth curve was drawn. The bacteriophage SAP23 solution was incubated at 4, 37, 50, 60, 70, and 80 ℃ and pH 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 for 1 h, respectively, to determine its stability. A total of 41 MRSA strains stored in the Department of Microbiology of Army Medical University (the Third Military Medical University) were used to determine the host spectrum of bacteriophage SAP23. Results: The bacteriophage SAP23 could form a transparent plaque on the host bacteria double-layer agar plate. The bacteriophage SAP23 has a polyhedral head with (88±4) nm in diameter and a tail with (279±21) nm in length and (22.6±2.6) nm in width. The bacteriophage SAP23 has a linear, double-stranded DNA with a full length of 151 618 bp and 11 681 bp long terminal repeats sequence in the sequence ends. There were 220 open reading frames predicted and the bacteriophage could encode 4 transfer RNAs, while no resistance genes or virulence factors were found. The annotation function of bacteriophage SAP23 genes could be divided into 5 groups. The GenBank accession number was MZ427930. According to the genomic collinearity analysis, there were 5 local collinear blocks in the whole genome between the bacteriophage SAP23 and the chosen 6 Staphylococcus bacteriophages, while within or outside the local collinear region, there were still some differences. The bacteriophage SAP23 belonged to the Herelleviridae family, Twortvirinae subfamily, and Kayvirus genus. The optimal MOI of bacteriophage SAP23 was 0.010 0, and the optimal adsorption time was 10 min. The bacteriophage SAP23 had a latent period of 20 min, and a growth phase of 80 min. The bacteriophage SAP23 was able to remain stable at the temperature between 4 and 37 ℃ and at the pH values between 4 and 9. The bacteriophage SAP23 could lyse 3 of the 41 tested MRSA strains. Conclusions: The bacteriophage SAP23 is a member of the Herelleviridae family, Twortvirinae subfamily, and Kayvirus genus. The bacteriophage SAP23 has a good tolerance for temperature and acid-base and a short latent period, and can lyse MRSA effectively. The bacteriophage SAP23 is a new type of potent narrow-spectrum bacteriophage without virulence factors and resistance genes.

Molecular characterization of Staphylococcus aureus ST6 and ST7 isolates from food-borne illness outbreaks / 中华预防医学杂志

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.

Portación nasal, antibiotipo y genotipo de cepas de Staphylococcus aureus aisladas en estudiantes de Medicina y de Enfermería Campus San Felipe, Universidad de Valparaíso, Chile, durante el año 2017 / Nasal carriage, antibiotype and genotype of isolated Staphylococcus aureus from Medicine and Nursing students of Campus San Felipe, University of Valparaiso, Chile, during 2017

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.

Community-genotype methicillin-resistant Staphylococcus aureus skin and soft tissue infections in Latin America: a systematic review

ABSTRACT Background: Community-genotype methicillin-resistant Staphylococcus aureus (CG-MRSA) emerged in the 1990s as a global community pathogen primarily involved in skin and soft tissue infections (SSTIs) and pneumonia. To date, the CG-MRSA SSTI burden in Latin America (LA) has not been assessed. Objective: The main objective of this study was to report the rate and genotypes of community-genotype methicillin-resistant Staphylococcus aureus (CG-MRSA) causing community-onset skin and soft tissue infections (CO-SSTIs) in LA over the last two decades. In addition, this research determined relevant data related to SSTIs due to CG-MRSA, including risk factors, other invasive diseases, and mortality. Data sources: Relevant literature was searched and extracted from five major databases: Embase, PubMed, LILACS, SciELO, and Web of Science. Methods: A systematic review was performed, and a narrative review was constructed. Results: An analysis of 11 studies identified epidemiological data across LA, with Argentina presenting the highest percentage of SSTIs caused by CG-MRSA (88%). Other countries had rates of CG-MRSA infection ranging from 0 to 51%. Brazil had one of the lowest rates of CG-MRSA SSTI (4.5-25%). In Argentina, being younger than 50 years of age and having purulent lesions were predictive factors for CG-MRSA CO-SSTIs. In addition, the predominant genetic lineages in LA belonged to sequence types 8, 30, and 5 (ST8, ST30, and ST5). Conclusion: There are significant regional differences in the rates of CG-MRSA causing CO-SSTIs. It is not possible to conclude whether or not CG-MRSA CO-SSTIs resulted in more severe SSTI presentations or in a higher mortality rate.

Macrolide-lincosamide-streptogramin B resistance phenotypes and their associated genotypes in Staphylococcus aureus isolates from a tertiary level public hospital of Uruguay / Fenotipos de resistencia a macrólidos lincosamidas-estreptograminas B y sus genotipos asociados en Staphylococcus aureus aislados en un hospital público de nivel terciario en Uruguay

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.

Detection of the mecA gene in Staphylococcus spp. isolated from the nasal cavity of pigs - Preliminary data / [Detecção do gene mecA em Staphylococcus spp. isolados da cavidade nasal de suínos - dados preliminares]

O objetivo deste estudo foi realizar a caracterização genética de Staphylococcus spp. resistentes a meticilina isolados de suínos. Foram coletadas 30 amostras de swab nasal de suínos, abatidos em um frigorífico com Serviço de Inspeção Federal. Os isolados foram submetidos a análises macro e microscópicas que, em seguida, para detectar a resistência bacteriana, foram submetidos a ensaios fenotípicos da sensibilidade aos antimicrobianos. Posteriormente, as amostras resistentes a oxacilina, foram submetidas à reação em cadeia pela polimerase (PCR) para verificar a presença do gene mecA. Das 30 amostras analisadas, foram isolados 12 (40%) Staphylococcus spp. coagulase positiva, e 18 (60%) coagulase negativa, e, dentre os isolados, 26 (86,66%) foram resistentes a oxacilina sendo possível detectar o gene mecA em seis (23%) amostras. Este estudo evidencia a presença de genes de resistência em microrganismos comuns a microbiota de animais de produção que podem ser transmitidos ao homem. Além de chamar a atenção para a frequência e quantidade de antimicrobianos aos quais estes animais são expostos durante toda sua vida, podendo ser considerado um problema para a saúde única.(AU)

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.

Prevalencia y caracterización genotípica de cepas de Staphylococcus aureus resistente a meticilina aisladas en un hospital regional mexicano / Prevalence and genotypic characterization of methicillin-resistant strains of Staphylococcus aureus isolated in a Mexican regional hospital

Resumen Introducción: Staphylococcus aureus es uno de los patógenos con mayor prevalencia en el mundo, asociado a una alta tasa de mortalidad y un rápido desarrollo de resistencia a los antimicrobianos. A pesar de su patogenicidad, su seguimiento epidemiológico en México es escaso. Objetivo: Analizar la epidemiología molecular local y determinar el origen clonal de cepas resistentes a meticilina (RM) aisladas de pacientes internados en el Hospital Central "Dr. Ignacio Morones Prieto". Métodos: Se llevó a cabo un estudio prospectivo de corte transversal, de julio a diciembre de 2016. La caracterización de las cepas se realizó mediante genotipificación Spa, la determinación por RPC punto final de la frecuencia de genes de virulencia específicos y su antibiograma. Resultados: A partir de estos datos, se obtuvo que la prevalencia de S. aureus RM fue de 25,7%, destacando la presencia del tipo Spa t895 en 76% de las cepas resistentes y un patrón similar de susceptibilidad a antimicrobianos. Conclusión: Los resultados de este estudio indican que la prevalencia regional de SARM no se ha modificado en los últimos 10 años y proporcionan información valiosa del origen clonal y los factores de virulencia de las cepas de S. aureus aisladas en la región.

Abstract Background: Staphylococcus aureus is one of most prevalent pathogens in the world associated with a high mortality rate and a rapid development of resistance to antibiotics. Despite its pathogenicity, epidemiological monitoring in Mexico is scarce. Aim: To analyze the local molecular epidemiology and determine the clonal origin of methicillin-resistant (MR) strains isolated from patients admitted to Hospital "Dr. Ignacio Morones Prieto". Methods: A cross-sectional prospective study was carried out from July to December 2016. The characterization of the strains was carried out by Spa genotyping, frequency of specific virulence genes by PCR and antibiogram. Results: The prevalence of MRSA was 25.7%, highlighting the presence of the Spa type t895 in 76% of the resistant strains and a similar pattern of susceptibility to antibiotics. Conclusion: The results of this study indicate that the regional prevalence of MRSA has not changed in the last 10 years and provide valuable information on the clonal origin and the virulence factors of the strains of S. aureus isolated in the region.

Resistance profile to antimicrobials agents in methicillin-resistant Staphylococcus aureus isolated from hospitals in South Brazil between 2014-2019

Abstract INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) is a common pathogen causing healthcare-associated infections. Owing to the restricted use of beta-lactams in MRSA infections, non-beta-lactam antimicrobials are required for treatment. However, MRSA can develop resistance mechanisms to non-beta-lactam antimicrobials, which reduces viable treatment options. Here, we evaluated the antimicrobial susceptibility and resistance genes of MRSA isolated from hospitalized patients in South Brazil. METHODS: The antimicrobial susceptibilities of hospital MRSA (217) isolates were determined by disk diffusion or microdilution methods. Additionally, the presence of 14 resistance genes and SCCmec typing was performed by PCR. RESULTS: Among the antimicrobials tested, we observed high erythromycin (74.2%), ciprofloxacin (64.5%), and clindamycin (46.1%) resistance rates and complete susceptibility to linezolid and vancomycin. Seventeen different patterns of MRSA antimicrobial resistance were observed, of which 42.9% represented multidrug resistance. Among erythromycin-resistant MRSA, 53.4%, 45.3%, 37.9%, 13.0%, and 6.8% carried ermA, msrA, msrB, ermC, and ermB genes, respectively. Among clindamycin-resistant MRSA, 83%, 17%, 10%, 4%, and 2% carried ermA, ermC, ermB, linA, and linB genes, respectively. Among gentamicin-resistant MRSA, 96.8%, 83.9%, and 9.7% carried aac(6')/aph(2''), aph(3')-IIIa, and ant(4')-Ia genes, respectively. Among tetracycline-resistant MRSA, 6.5% and 93.5% carried tetK and tetM genes, respectively. Lastly, among trimethoprim/sulfamethoxazole-resistant MRSA, 13.3% and 100% carried dfrA and dfrG genes, respectively. The SCCmec type IV isolates were detected more frequently, whereas the SCCmec type III isolates exhibited higher multidrug resistance. CONCLUSIONS: The study data provides information regarding the MRSA resistance profile in South Brazil that is associated with the clinical conditions of patients and can contribute to clinical decision-making.

Identification and characterization of methicillin-resistant Staphylococcus spp. isolated from surfaces near patients in an intensive care unit of a hospital in southeastern Brazil

Abstract INTRODUCTION: Contaminated hospital environments contribute to the transmission of microorganisms associated with healthcare. Contaminated surfaces handled by patients or healthcare professionals are a source of microorganism transmission by hand. Methicillin-resistant Staphylococcus bacteria are among the main agents responsible for increasing healthcare-associated infections in Brazil and worldwide. METHODS: The objective of this study was to screen and characterize methicillin-resistant Staphylococcus spp. on surfaces near patients in an intensive care unit. Microbiological samples, collected from ten beds in an intensive care unit with five sampling sites, were inoculated into a methicillin-resistant Staphylococcus aureus chromogenic medium. MALDI-TOF and PCR analyses were used to identify the bacteria. Antimicrobial susceptibility was determined using the disk diffusion test. The presence of the mecA gene was investigated using PCR. RESULTS: We observed that 44 out of the 50 sampling sites presented grown isolates in the methicillin-resistant Staphylococcus aureus medium. The incidence of isolated microorganisms on the right side rail, left side rail, tables, infusion pump keypad, and cardiac monitor were 18.8 %, 36.7 %, 10.9 %, 2.4 %, and 31 %, respectively. The 42 isolates included in this study were identified as coagulase-negative Staphylococcus. All of these microorganisms were multidrug-resistant and mecA gene-positive. CONCLUSIONS: This study identified the presence of methicillin-resistant coagulase-negative Staphylococcus on the beds of an intensive care unit, providing evidence for the necessity of assertive actions to decrease the risk of healthcare-associated infections at the site.

Resistencia a la meticilina y producción de biopelícula en aislamientos clínicos de Staphylococcus aureus y Staphylococcus coagulasa negativa en México / Methicillin resistance and biofilm production in clinical isolates of Staphylococcus aureus and coagulase-negative Staphylococcus in México

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.

Molecular characteristics of methicillin-resistant Staphylococcus aureus isolates from hospital and community environments in northeastern Brazil

ABSTRACT This study characterized 30 MRSA isolates from intensive care unit (ICU) environment and equipment surfaces and healthy children. The SCCmec types I, IVa and V were detected in HA-MRSA isolates while CA-MRSA showed the SCCmec type IVa and V. Most isolates were classified as agr group II. All isolates presented the sei gene, and only HA-MRSA were positive for etb e tst genes. Three genotypes were related to Pediatric (ST5/SCCmecIV) and Berlin (ST45/SCCmecIV) clones. The present study showed molecular similarity between CA- and HA-MRSA isolates in hospital and community settings in a Brazilian region.

Prevalence of methicillin resistant staphylococcus aureus isolated from saliva samples of patients with oral squamous cell carcinoma / revalencia de Staphylococcus aureus resistente a la meticilina en muestras de saliva de pacientes con carcinoma oral de células escamosas

Objectives: To study the prevalence of methicillin resistant Staphylococcus aureus (MRSA) in saliva samples of pre-surgical oral squamous cell carcinoma (OSCC) patients along with their resistance pattern to other antibiotics. Methods: Saliva samples of OSCC patients were collected and processed for isolation of MRSA. Staphylococcus aureus isolates were primarily identified using standard microbiological methods like biochemical assays, specialized media and latex agglutination test. Confirmation of MRSA strains was done by growing the isolates on MRSA agar and by using PCR to amplify two MRSA specific genes. All the isolated Staphylococcus aureus strains were subjected to antibiotic sensitivity tests. Results: A total of 17 Staphylococcus aureus strains were isolated from 50 saliva samples of pre-surgical OSCC patients of which 13 were confirmed to be MRSA. These MRSA strains were also found to be mostly resistant to other commonly used antibiotics. Univariate analysis revealed that most patients with MRSA infections had a prior history of hospitalization and surgery. Also, it was confirmed that patients with other comorbidities and infections were more prone to having MRSA present in the saliva. Conclusion: The majority of Staphylococcus aureus isolates from the saliva of OSCC patients were MRSA, and were resistant to several other commonly used antibiotics.

Objetivos: Estudiar la prevalencia de Staphylococcus aureus resistente a la meticilina (MRSA) en muestras de saliva prequirúrgicas de pacientes con carcinoma oral de células escamosas (COCE) junto con su patrón de resistencia a otros antibióticos. Métodos: Se recolectaron muestras de saliva de pacientes con COCE y se procesaron para el aislamiento de SARM. Los aislamientos de Staphylococcus aureus se identificaron principalmente mediante métodos microbiológicos estándar, como los análisis bioquímicos, los medios especializados y la prueba de aglutinación con látex. La confirmación de las cepas de SARM se realizó cultivando los aislados en agar SARM y utilizando PCR para amplificar dos genes específicos de SARM. Todas las cepas aisladas de Staphylococcus aureus se sometieron a pruebas de sensibilidad a los antibióticos. Resultados: Se aislaron un total de 17 cepas de Staphylococcus aureus a partir de 50 muestras de saliva de pacientes prequirúrgicos con COCE, de los cuales solo se confirmó que 13 eran SARM. También se encontró que estas cepas de SARM son resistentes a otros antibióticos de uso común. El análisis univariado reveló que la mayoría de los pacientes con infecciones por SARM tenían antecedentes previos de hospitalización y cirugía. Además, se confirmó que los pacientes con otras comorbilidades e infecciones eran más propensos a las infecciones por SARM. Conclusión: la mayoría de los aislamientos de Staphylococcus aureusde la saliva de los pacientes con OSCC fueron MRSA y fueron resistentes a varios otros antibióticos de uso común.

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.

Molecular characteristics and virulence gene profiles of Staphylococcus aureus causing bloodstream infection

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.

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.

High frequency of methicillin-susceptible and methicillin-resistant Staphylococcus aureus in children under 1 year old with skin and soft tissue infections / Alta frequência de S. aureus (MSSA-MRSA) em crianças com menos de um ano deidade com infecções de pele e do tecido mole

Abstract Objective: Staphylococcus aureus is responsible for a large number of infections in pediatric population; however, information about the behavior of such infections in this population is limited. The aim of the study was to describe the clinical, epidemiological, and molecular characteristics of infections caused by methicillin-susceptible and resistant S. aureus (MSSA-MRSA) in a pediatric population. Method: A cross-sectional descriptive study in patients from birth to 14 years of age from three high-complexity institutions was conducted (2008-2010). All patients infected with methicillin-resistant S. aureus and a representative sample of patients infected with methicillin-susceptible S. aureus were included. Clinical and epidemiological information was obtained from medical records and molecular characterization included spa typing, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST). In addition, staphylococcal cassette chromosome mec (SCCmec) and virulence factor genes were detected. Results: A total of 182 patients, 65 with methicillin-susceptible S. aureus infections and 117 with methicillin-resistant S. aureus infections, were included in the study; 41.4% of the patients being under 1 year. The most frequent infections were of the skin and soft tissues. Backgrounds such as having stayed in day care centers and previous use of antibiotics were more common in patients with methicillin-resistant S. aureus infections (p ≤ 0.05). Sixteen clonal complexes were identified and methicillin-susceptible S. aureus strains were more diverse. The most common cassette was staphylococcal cassette chromosomemec IVc (70.8%), which was linked to Panton-Valentine leukocidin (pvl). Conclusions: In contrast with other locations, a prevalence of infections in children under 1 year of age in the city could be observed; this emphasizes the importance of epidemiological knowledge at the local level.

Resumo Objetivo: O Staphylococcus aureus é responsável por um grande número de infecções na população pediátrica; contudo, as informações sobre o comportamento dessas infecções nessa população são limitadas. O objetivo do estudo foi descrever as características clínicas, epidemiológicas e moleculares de infecções causadas por Staphylococcus aureus suscetíveis e resistentes à meticilina (MSSA-MSRA) em uma população pediátrica. Método: Um estudo transversal descritivo foi realizado em pacientes entre 0 e 14 anos de idade de três instituições de alta complexidade (2008-2010). Todos os pacientes infectados com S. aureus resistentes à meticilina e uma amostra representativa de pacientes infectados com S. aureus suscetíveis à meticilina foram incluídos. As informações clínicas e epidemiológicas foram obtidas de prontuários médicos, e a caracterização molecular incluiu tipagem spa, Eletroforese em Gel de Campo Pulsado (PFGE) e Tipagem de sequências multilocus (MLST). Além disso, o Cassete Cromossômico Estafilocócico mec (SCCmec) e genes de fatores de virulência foram detectados. Resultados: 182 pacientes, 65 com infecções por S. aureus suscetíveis à meticilina e 117 com infecções por S. aureus resistentes à meticilina, foram incluídos no estudo; 41,4% dos pacientes com menos de um ano de idade. As infecções mais frequentes foram da pele e dos tecidos moles. Os históricos como internações em centros de atendimento e o uso prévio de antibióticos foram mais comuns em pacientes com infecções por S. aureus resistentes à meticilina (p ≤ 0,05). Dezesseis complexos clonais foram identificados, e as cepas de S. aureus suscetíveis à meticilina foram mais diversificadas. O cassete mais comum foi o Cassete Cromossômico Estafilocócicomec IVc (70,8%), relacionado à leucocidina de panton-valentine (pvl). Conclusões: Em comparação a outros locais, observamos uma prevalência de infecções em crianças com menos de um ano de idade na cidade; o que enfatiza a importância de conhecer a epidemiologia em nível local.