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

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

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

Methicillin-resistant Staphylococcus aureus intracranial abscess: An analytical series and review on molecular, surgical and medical aspects

Purpose: Intracranial abscess caused by methicillin-resistant Staphylococcus aureus (MRSA) is rare and unexplored. The aim of the present study is to examine the prevalence, clinical and molecular characteristics, treatment options and outcome of MRSA intracranial abscess over a period of 6 years. Patientsand Methods: A total of 21 patients were included in this retrospective study. The demographic and clinical details of all the patients were collected. Molecular typing including staphylococcal cassette chromosome mec typing, spa typing and polymerase chain reaction of Panton–Valentine leucocidin toxin (PVL) gene for the latter 6 isolates was performed. Results: The paediatric population was the most affected group (33.3%). The primary route of infection was post-operative/trauma in 7 (33.3%) cases. All the patients were treated surgically either by aspiration or excision. Fifteen (71%) patients received anti-MRSA treatment with vancomycin or linezolid, where linezolid-treated patients showed better prognosis. Of the 11 patients who were on follow-up, unfavourable outcome was observed in 3 (27.3%) cases and 8 (72.7%) cases improved. The molecular typing of six isolates revealed four community-associated (CA) MRSA, one each of livestock-associated (LA) and healthcare-associated MRSA with PVL gene noted in all. Conclusion: We propose that timely diagnosis, surgical intervention and appropriate anti-MRSA treatment would contribute to better outcome. The occurrence of CA-MRSA and LA-MRSA infection in the central nervous system signifies the threat from the community and livestock reservoir, thus drawing attention towards surveillance and tracking to understand the epidemiology and implement infection control measures.

Antibiotic resistance and molecular epidemiology characteristics of methicillin-resistant Staphylococcus aureus in Shenzhen area / 中国人兽共患病学报

The aim of this study is to investigate antibiotic resistance and molecular epidemiology characteristics of methicillin-resistant Staphylococcus aureus (MRSA) in Shenzhen area.We collected 428 Staphylococcus aureus isolates from eight hospitals in Shenzhen in 2012.According to the results of minimum inhibitory concentration (MIC) to cefoxitin,26.2％ of Staphylococcus aureus isolates (112/428) were identified as MRSA.The MIC of 10 antimicrobial agents was determined by agar dilution method.Panton-Valentine leucocidin(PVL) was detected by polymerase chain reaction(PCR).Positive strains of PVL were detected by multilocus sequence typing(MLST).Among the 112 strains,the resistance rates to trimethoprim-sulfamethoxazole,moxifloxacin,ciprofloxacin,gentamicin,erythromycin,clindamycin and tetracycline were 4.46％,12.50％,16.96％,19.64％,46.42％,25.00％ and 26.79％ respectively.No isolates resistant to vancomycin,linezolid and teicoplanin were found.Among the 112 strains,there were 13 (11.61％) strains carried PVL gene.There were no significant differences in the resistance rates of PVL positive strains and negative strains to 10 kinds of antimicrobial agents.Among the 13 strains carried PVL gene,7 kinds of old sequences and 1 kind of new sequence type were found by MLST.ST338 and ST25 were the most common type.All the data indicate that surveillance of MRSA in Shenzhen has a distinct genetic background from other regions.

Methicillin-resistant Staphylococcus aureus strains carrying Panton-Valentine leukocidin genes: clinical and molecular characteristics / 中华微生物学和免疫学杂志

Objective To isolate and identify the methicillin-resistant Staphylococcus aureus (MRSA) strains carrying Panton-Valentine leukocidin genes (pvl+-MRSA) from clinical samples and to further understand their molecular characteristics and infections caused by them.Methods Drug susceptibility test was performed to detect the drug resistance in 259 MRSA strains.pvl+-MRSA strains were screened out from those MRSA strains using cefoxitin slip test and mecA gene detection by PCR.Multiple PCR and multilocus sequence typing (MLST) were used for SCCmec and ST typing.Pulsed-field gel electrophoresis (PFGE) and cluster analysis were used to understand the genetic and epidemic features of the pvl+-MRSA strains.Different types of infections and diseases caused by the pvl+-MRSA strains were analyzed.ResultsAmong the 259 MRSA strains, 51 pvl+-MRSA strains were identified (19.7%, 51/259), of which 29 and 22 strains were respectively isolated from patients with community-acquired and hospital-acquired infections.ST59-SCCmecⅢ (35.3%, 18/51) was the predominant type of the 51 pvl+-MRSA strains, followed by ST59-SCCmecⅣ(25.5%, 13/51).But no predominant clone among those strains was revealed by the result of PFGE.Children, young-and middle-aged patients (≤44 years old) had a significantly higher positive rate of pvl+-MRSA than patients aged ≥45 years (P<0.05).Skin and soft tissue infection (47.1%, 24/51) was the most common disease caused by the pvl+-MRSA strains (P<0.05), followed by pneumonia (17.6%, 9/51).The pvl+-MRSA strains showed lower resistance to levofloxacin, gentamycin and rifampicine (7.8%-21.6%).No moxifloxacin-, nitrofurantoin-or linezolid-resistant pvl+-MRSA strains were identified.Conclusion The rate of pvl+-MRSA infection is high in the local population.ST59-SCCmecⅢ and ST59-SCCmecⅣ are the predominant types of pvl+ MRSA strains.Children, young-and middle-aged persons are the susceptible population.Skin and soft tissue infection and pneumonia are the common diseases caused by pvl+-MRSA.

Molecular characterisation of Panton–Valentine leucocidin‑producing methicillin‑resistant Staphylococcus aureus clones isolated from the main hospitals in Taif, KSA.

Introduction: Panton–Valentine leucocidin (PVL) is a bicomponent pore‑forming cytolytic toxin encoded by the lukF‑PV and lukS‑PV genes. Community‑acquired methicillin‑resistant Staphylococcus aureus (CA‑MRSA) may carry the pvl genes which may be related to increased disease severity. This study aimed to characterise the PVL‑producing MRSA recovered from different Taif Hospitals, Saudi Arabia. Methods: The study included 45 hospital‑acquired‑MRSA (HA‑MRSA) and 26 CA‑MRSA strains which were identified from 445 S. aureus strains isolated from different clinical samples. MRSA strains were identified by standard oxacillin salt agar screening procedure and by the detection of the mecA gene by the polymerase chain reaction (PCR). Detection of the S. aureus‑specific femA, mecA and pvl genes was performed by multiplex PCR. PCR‑restriction fragment length polymorphism (PCR‑RFLP) analysis was done for coagulase (coa) gene. Results: The staphylococcal cassette chromosome mec types of the 45 HA‑MRSA strains were Type I (n = 24), Type II (n = 7) and Type III (n = 14) whereas the 26 CA‑MRSA strains were Type IV (n = 14), Type V (n = 11) and one isolate was non‑typeable. All the HA‑MRSA and six CA‑MRSA strains were PVL‑negative PCR‑RFLP analysis of coa gene showed that PVL‑positive MRSA (n = 20) isolates showed six different patterns, and five patterns were shared by PVL‑positive methicillin‑susceptible S. aureus (MSSA). The eighth pattern was the most frequent in both MRSA and MSSA. Conclusion: PVL is more frequent among CA‑MRSA than MSSA. All the HA‑MRSA and 25% of CA‑MRSA strains were negative for PVL. The pvl gene was related to the severity of infection but not related to coa gene RFLP pattern.

Frecuencia de staphylococcus aureus meticilino resistente y del factor de virulencia PVL en pacientes ambulatorios con infección de piel y partes blandas de Asunción, Paraguay / Frequency of methicillin-resistant staphylococcus aureusand PVL virulence factor in ambulatory patients with skinand soft tissue infections of Asuncion, Paraguay

Staphylococcus aureus (S. aureus) es actualmente el agente etiológico más frecuente en infecciones de piel y tejidos blandos. El S. aureus meticilino resistente (SAMR) aislado en infecciones de pacientes de la comunidad ha ido aumentando, constituyéndose en un problema de salud pública a nivel mundial. En Paraguay existen pocos registros sobre la meticilino resistencia y factores de virulencia a nivel comunitario, por lo que se realizó este estudio observacional descriptivo para determinar la frecuencia de SAMR y del factor de virulencia leucocidina de Panton Valentine (PVL-Panton Valentine leukocidin), así como el perfil de resistencia antimicrobiana acompañante a la meticilino resistencia en S. aureus aisladosde infecciones de piel y partes blandas de pacientes ambulatorios de dos laboratorios de Asunción, Paraguay, entre octubre de 2012 a febrero de 2014. La identificación bacteriana se realizó mediante técnicas microbiológicas convencionales y la susceptibilidad antimicrobiana por la prueba de difusión en disco. Elgen mecA y luk-PV fueron detectados por la técnica de PCR. De los 70 aislados de S. aureus estudiados, el 54,3% (38/70) fue SAMR tanto por método fenotípico como molecular. La frecuenciade PVL fue de 15,7% (11/70), siendo mayor en los SAMR (21%; 8/38) que en los SAMS (9,4%; 3/32). El 2,6% de los SAMR presentó resistencia a ciprofloxacina, no se observó multiresistencia en ningún aislado. Se encontró alta frecuencia de SAMR comparado con reportes previos en Paraguay. Se requiere fortalecer estrategias de vigilancia, prevención y control de la resistencia bacteriana en ambientes hospitalarios y de la comunidad.

Staphylococcus aureus (S. aureus) is currently the most common etiologic agentof skin and soft tissue infections. The isolation of methicillin-resistant S. aureus(MRSA) from infections of patients in the community has increased, becoming a public health problem worldwide. In Paraguay, there are few records aboutmethicillin resistance and virulence factors at community level. Therefore, this descriptive observational study was performed to determine the frequency of MRSA and factor virulence of Panton-Valentine leukocidin (PVL) as well as the antimicrobial resistance profile accompanying methicillin resistance in S. aureusisolated from skin and soft tissue infections in ambulatory patients from two laboratories of Asuncion, Paraguay from October, 2012 to February, 2014. The bacterial identification was performed using conventional microbiological techniques and the antimicrobial susceptibility was determined by disk diffusion. The mecA andluk-PV genes were detected by PCR technique. Out of the 70 S. aureus isolates studied, 54.3% (38/70) was SAMR by phenotypic and molecular methods. PVL frequency was 15.7% (11/70) being higher in MRSA (21%; 8/38) than in the SAMS (9.4%; 3/32), 2.6% of the MRSA was resistant to ciprofloxacin and multidrug resistance was not observed in any isolates. A high frequency of MRSA was found compared with previous reports in Paraguay. It is required to strengthen surveillance, prevention and control of bacterial resistance strategies in hospital and community environments.

Meta-analysis on epidemiology of iatrogenic-borne methicillin-resistant Staphylococcus aureus / 中华流行病学杂志

Objective To study the molecular-biologic characteristics and epidemiological status of iatrogenic related Community-acquired methicillin-resistant Staphylococcus (S.) aureus (CA-MRSA) in China through Meta-analysis.Methods Data through systematic searching for peer-reviewed articles published before December 3rd,2015 from 4 main electronic databases including China National Knowledge Infrastructure (CNKI),Wanfang Data,PubMed and Web of Science Core Collection was collected,for this Meta-analysis.PRISMA guidelines were followed and the proportion of MRSA,CA-MRSA,hospital-acquired MRSA (HA-MRSA) and panton-valentine leucocidin (PVL) gene in certain populations were quantitatively analyzed by Stata 13.0 software.Results Average proportion of CA-MRSA from S.aureus was 12％ (95％CI:8％-16％).CA-MRSA in MRSA was 18％ (95％CI:12％-24％).42.1％ (95％CI:20.4％-63.7％) of the CA-MRSA carried a PVL gene,and the number was higher than general MRSA (t =-2.99,P=0.011).Conclusion CA-MRSA was in lower proportion than HA-MRSA,both seen in general MRSA and in S.aureu.s,but under higher proportion of carrying the PVL gene.Transmission of CA-MRSA could be prevented within the general population through conducting effective surveillances and preventive programs.

Meta-analysis on epidemiology of iatrogenic-borne methicillin-resistant Staphylococcus aureus / 中华流行病学杂志

Objective To study the molecular-biologic characteristics and epidemiological status of iatrogenic related Community-acquired methicillin-resistant Staphylococcus (S.) aureus (CA-MRSA) in China through Meta-analysis.Methods Data through systematic searching for peer-reviewed articles published before December 3rd,2015 from 4 main electronic databases including China National Knowledge Infrastructure (CNKI),Wanfang Data,PubMed and Web of Science Core Collection was collected,for this Meta-analysis.PRISMA guidelines were followed and the proportion of MRSA,CA-MRSA,hospital-acquired MRSA (HA-MRSA) and panton-valentine leucocidin (PVL) gene in certain populations were quantitatively analyzed by Stata 13.0 software.Results Average proportion of CA-MRSA from S.aureus was 12％ (95％CI:8％-16％).CA-MRSA in MRSA was 18％ (95％CI:12％-24％).42.1％ (95％CI:20.4％-63.7％) of the CA-MRSA carried a PVL gene,and the number was higher than general MRSA (t =-2.99,P=0.011).Conclusion CA-MRSA was in lower proportion than HA-MRSA,both seen in general MRSA and in S.aureu.s,but under higher proportion of carrying the PVL gene.Transmission of CA-MRSA could be prevented within the general population through conducting effective surveillances and preventive programs.

Effect of subinhibitory concentrations of antibiotics on Staphylococcus aureus producing panton-valentine leukocidin / 安徽医科大学学报

Objective To explore the effect of subinhibitory concentrations (sub-MICs) of four antibiotics on pan-ton-valentine leucocidin ( PVL ) expression by Staphylococcus aureus . Methods Eight strains of PVL-positive Staphylococcus aureus were isolated by PCR. The MICs of these antibiotics were determined by constant dilution. then, PVL expression of Staphylococcus aureus was measured at different MICs of these antibiotics by ELISA. Re-sults Clindamycin, linezolid and tigecycline all could reduce the expression of PVL at 1 / 8 MIC ~ 1 / 2 MIC. after 4 and 6 hours of culturing, the relative PVL mRNA expression was reduced about 17% ~ 82% , 8% ~ 85% and 11% ~ 78% by clindamycin, linezolid and tigecycline, respectively. The protein expression of PVL was reduced by 65% and 83% under 1 / 4 and 1 / 2 MIC of clindamycin, and reduced by 40% and 61% under 1 / 4 and 1 / 2 MIC of linezolid, and reduced by 61% only at 1 / 2 MIC of tigecycline. There had no effect of vancomycin on PVL expres-sion. Conclusion The effects of four antibiotics on PVL expression at sub-MICs were different. Clindamycin and linezolid could significantly reduced PVL expression. Tigecycline colud reduced PVL expression only at high sub-MICs. Vancomycin had no effect.

Effect of PDTC on the NF-κB activation and the expression of inflammatory cytokines in THP-1 macrophages induced by rPVL / 中华微生物学和免疫学杂志

Objective To investigate effect of PDTC on the NF-κB activation and the expression of inflammatory cytokines in THP-1 macrophages induced by rPVL.Methods The study was divided into three groups:PBS-treated control group,rPVL-treated group and PDTC group which was given 100 μmol/L PDTC at 60 min before rPVL exposure.Immunohistochemistry method was used to test the translocation of NF-κB protein; the expression of NF-κB and IκB protein was analyzed by Western blot; RT-PCR and ELISA was performed to test expression of IL-8 and L-6 in THP-1 macrophages.Results Compared with rPVL-treated group,the activation of NF-κB and the expression of IL-8 and L-6 in PDTC group was significantly decreased.The protein secretions of IL-8 and IL-6 were reduced to 6.78 ng/ml,3.88 ng/ml,receptively(P ＜0.05).Conclusion The inhibitor of NF-κB,PDTC,could significantly decrease the secretion of pro-inflammatory in THP-1 macrophages by rPVL,and it suggested that PDTC played an important role in protecting tissues from damage induced by rPVL.

Panton-valentine leukocidin induce THP-1 macrophages IL-8 and IL-6 response through nuclear TLR4/NF-κB pathway / 中华微生物学和免疫学杂志

Objective To investigate the influence of panton-valentine leucocidin (PVL) on expression of Toll like receptor 4(TLR4)/nuclear factor-kappa B(NF-κB) signals and IL-8,IL-6 in THP-1 macrophages,and to study the mechanism of PVL-related lung tissue damage.Methods THP-1 cells were cultured in the presence of 100 nmol/L phorbol-12-myristate 3-acetate (PMA) for 48 h to induce monocytemacrophage differentiation.rPVL-F and rPVL-S were induced and expressed from the recombinant plasmid,respectively purified with chromatographic column. After that,THP-1 macrophages were incubated with rPVL,and then ELISA was performed to test expression of IL-8 and L-6 in supernatants fluid; RT-PCR was performed to detect expression of IL-8,L-6 and TLR4 ; NF-κB was analyzed by Western blot and immunohistochemistry method.Results PVL was able to induce expression of IL-8 and IL-6 in THP-1 macrophages in time-and concentration-dependent manners.PVL could also significantly promote the activation of TLR4/NF-κB signals.Conclusion PVL can activate the expression of TLR4/NF-κB signals,and increased the high expression of inflammatory cytokines.Maybe it's the mechanism of action of PVL exerts the function of lung tissue damage.