Asociación entre los criterios de clasificación genotípica de Staphylococcus aureus resistente a meticilina que se obtuvo mediante electroforesis en geles de campos pulsantes y mediante reacción en cadena de la polimerasa de regiones hipervariables del gen mecA (original) (raw)
Related papers
The cassette chromosome mec (SCCmec) present in methicillin-resistant Staphylococcus aureus (MRSA) has two essential components, the ccr gene complex and the mec gene complex. Additionally, SCCmec has non-essential components called J regions which are used for MRSA subtyping. This study was performed to determine subtypes MRSA strains carrying SCCmec type I based on polymorphism of regions located downstream of the mecA gene. A total of 98 MRSA strains carrying SCCmec type I isolated from patients hospitalized at the County Hospital of Valdivia (Chile) between May 2007 and May 2008, were analyzed by multiplex PCR designed to amplify the mecA gene and 7 DNA hypervariable regions located around the mecA gene. MRSA strains were classified into seventeen genotypes accordingly to amplification patterns of DNA hypervariable regions. Five genotypes showed amplification patterns previously described. The remaining twelve genotypes showed new amplification patterns. Genotypes 18 and Genotype 19 were the most frequently detected. Regions HVR, Ins117 and pI258 stand out as being present in more than 60% of tested isolates. The acquisition of hypervariable regions by MRSA is a continuous horizontal transfer process through which the SCCmec have been preserved intact, or even may give rise to new types and subtypes of SCCmec. Therefore it is possible to infer that most MRSA strains isolated at the County Hospital of Valdivia (Chile) were originated from two local clones which correspond to Genotype 18 and Genotype 19.
Molecular identification and genotyping of MRSA isolates
Fems Immunology and Medical Microbiology, 2009
The aim of this study was to identify and characterize 97 methicillin-resistant Staphylococcus aureus (MRSA) isolates. Two conventional multiplex PCR assays, a real-time PCR assay and two PCR-based genotyping techniques including the spa- and hypervariable region (HVR)-typing methods were used to identify and characterize 97 MRSA strains isolated between April 2006 to September 2007 from the Steve Biko Academic Hospital. All MRSA isolates were positive for 16S rRNA gene, 99% were positive for the mecA gene and 4% positive for the Panton–Valentine leukocidin (PVL) gene. Staphylococcal cassette chromosome mec (SCCmec) typing showed 67% of isolates were SCCmec II [health-care-associated MRSA (HA-MRSA)], 14% were SCCmec III (HA-MRSA) and 4% were SCCmec IVd [community-associated MRSA (CA-MRSA)]. These CA-MRSA isolates showed a prevalence of 100% for the PVL gene. Using spa typing, three distinct clusters could be identified while HVR typing revealed six different clusters. CA-MRSA isolates were clustered together using spa and HVR typing. This study showed the prevalence of the CA-MRSA strains, PVL genes, the SCCmec types and the clonality of the MRSA strains. The high prevalence of the PVL gene in CA-MRSA isolates already residing in intensive care units was alarming and indicated the emergence of new MRSA lineages with a particular fitness for community and hospital transmission.
Annals of Clinical Microbiology and Antimicrobials, 2018
Background: Methicillin resistant Staphylococcus aureus (MRSA) constitutes a major global health concern causing hospital and community acquired infections. A wide diversity of MRSA genotypes are circulating in geographically related regions. Therefore understanding the molecular epidemiology of MRSA is fundamental to design control and clearance measures. Methods: A total of 106 MRSA isolates from infection (51) and carrier colonization sites (55) are characterized genetically based on SCCmec and MLST genotyping methods in addition to detection of PVL, TSST-1 and enterotoxins. Results: Sccmec-IV was the most frequently detected genotype (77.3%) followed by genotype V (13.2%) and III (9.4%). SCCmec-IVa was more prevalent among the carrier group (p value 0.002). CC80 was the most commonly identified clonal complex (CC). CC6 and CC22 were significantly more prevalent among the carrier group (p value 0.02 and 0.01, respectively). PVL was highly prevalent among the isolates (58.5%). PVL was detected in 70.6% of isolates from infection sites and 47.3% of isolates from carriers. All strains were sensitive to vancomycin, however, MRSA strains isolated from infection sites had significantly higher MICs compared to strains isolated from carrier colonization sites (p value 0.021). Five new sequence types mainly from the carrier group were identified and described in the study. Conclusions: MRSA population is genetically very diverse among carriers and infected individuals. With SCCmec type IV being most prevalent, this suggests a community origin of most MRSA strains. Therefore very well designed surveillance and clearance strategies should be prepared to prevent emergence and control spread of MRSA in the community.
Genotypic and phenotypic characteristics of Methicillin resistant Staphylococcus aureus MRSA strains
Staphylococcus aureus is a major cause of hospital-acquired infections worldwide. Increased frequency of methicillin-resistant Staphylococcus aureus (MRSA) in hospitalized patients and possibility of vancomycin resistance requires rapid and reliable characterization of isolates and control of MRSA spread in hospitals. Typing of isolates helps to understand the route of a hospital pathogen spread. The aim of this study was to investigate and compare genotypic and phenotypic characteristics of MRSA samples on three different geography locations. In addition, our aim was to evaluate three different methods of MRSA typing: spa-typing, agr-typing and GenoType MRSA. We included 104 samples of MRSA, isolated in 3 different geographical locations in clinical hospitals in Zagreb, Mostar, and Heidelberg, during the period of six months. Genotyping and phenotyping were done by spa-typing, agr-typing and dipstick assay GenoType MRSA. We failed to type all our samples by spa-typing. The most common spa-type in clinical hospital Zagreb was t041, in Mostar t001, and in Heidelberg t003.We analyzed 102/104 of our samples by agr-typing method. We did not find any agr-type IV in our locations. We analyzed all our samples by the dipstick assay GenoType MRSA. All isolates in our study were MRSA strains. In Zagreb there were no positive strains to PVL gene. In Mostar we have found 5/25 positive strains to PVL gene, in Heidelberg there was 1/49. PVL positive isolates were associated with spa-type t008 and agr-type I, thus, genetically, they were community-associated MRSA (CA-MRSA). Dipstick assay GenoType MRSA has demonstrated sufficient specificity, sensibility, simple performance and low cost, so we could introduce it to work in smaller laboratories. Using this method may expedite MRSA screening, thus preventing its spread in hospitals.
Bosnian Journal of Basic Medical Sciences, 2015
Staphylococcus aureus is a major cause of hospital-acquired infections worldwide. Increased frequency of methicillin-resistant Staphylococcus aureus (MRSA) in hospitalized patients and possibility of vancomycin resistance requires rapid and reliable characterization of isolates and control of MRSA spread in hospitals. Typing of isolates helps to understand the route of a hospital pathogen spread. The aim of this study was to investigate and compare genotypic and phenotypic characteristics of MRSA samples on three different geography locations. In addition, our aim was to evaluate three different methods of MRSA typing: spa-typing, agr-typing and GenoType MRSA. We included 104 samples of MRSA, isolated in 3 different geographical locations in clinical hospitals in Zagreb, Mostar, and Heidelberg, during the period of six months. Genotyping and phenotyping were done by spa-typing, agr-typing and dipstick assay GenoType MRSA. We failed to type all our samples by spa-typing. The most common spa-type in clinical hospital Zagreb was t041, in Mostar t001, and in Heidelberg t003.We analyzed 102/104 of our samples by agr-typing method. We did not find any agr-type IV in our locations. We analyzed all our samples by the dipstick assay GenoType MRSA. All isolates in our study were MRSA strains. In Zagreb there were no positive strains to PVL gene. In Mostar we have found 5/25 positive strains to PVL gene, in Heidelberg there was 1/49. PVL positive isolates were associated with spa-type t008 and agr-type I, thus, genetically, they were community-associated MRSA (CA-MRSA). Dipstick assay GenoType MRSA has demonstrated sufficient specificity, sensibility, simple performance and low cost, so we could introduce it to work in smaller laboratories. Using this method may expedite MRSA screening, thus preventing its spread in hospitals.
Intisari Sains Medis, 2022
Background: Methicillin-Resistant Staphylococcus aureus (MRSA) is a big challenge for health services worldwide which causes infections both in healthcare and community. Healthcare-associated MRSA (HA-MRSA) strains are shown to be resistant to beta-lactam antibiotics and several non-beta lactam antibiotics. At the same time, the community-associated MRSA (CA-MRSA) tends to be resistant to beta-lactam antibiotics. MRSA carried staphylococcal cassette chromosome (SCCmec) types I, II, III, IV, and V. SCCmec types I, II, and III were predominantly found in HA-MRSA strain while SCCmec types IV and V predominantly found in CA-MRSA strains. Furthermore, the panton valentine leukocidine (pvl) gene is commonly found in CA-MRSA strains. Therefore, this study aimed to determine the prevalence of SCCmec types I, II, III, and pvl gene in MRSA isolated from clinical specimens in Sanglah General Hospital. Methods: This study was a cross-sectional descriptive study. MRSA was isolated from clinical specimens (sputum, wounds, tissue, blood, etc.) from January 2020 to July 2021 and identified by the Vitek 2 Compact (Biomerieux, France) at the Clinical Microbiology Laboratory of Sanglah Hospital. Prevalence of SCCmec and pvl gene using PCR. Data were analyzed using Microsoft Excel version 2010 for Windows. Results: Most of the specimens (69.56%) were wound. Seventeen (73.91%) out of 23 MRSA isolates were positive for the SCCmec III and pvl gene, while none was positive for the SCCmec I and SCCmec II. About 19 (82.60%) isolates were resistant to two or more nonbeta-lactam antibiotics. Conclusions: The isolates of MRSA in this study were predominantly isolated from wound specimens, with the most prevalent genetic element being SCCmec III. In this study, although most MRSA isolates carried SCCmec III that suggested as HA-MRSA, however, most of the strains harbored the pvl gene. This interesting phenomenon needs to be further elucidated.
Clinical Microbiology and Infection, 2006
in a tertiary-care university hospital in Guadalajara, Mexico, were characterised by antibiotype, pulsed-field gel electrophoresis (PFGE) of SmaI macrorestriction fragments, and hybridisation of ClaI digests with mecA-and Tn554-specific DNA probes. Representatives of the single clonal type found were analysed by spa typing, multilocus sequence typing and staphylococcal chromosomal cassette mec (SCCmec) typing, and were tested for the presence of 22 virulence determinants and agr type. A single PFGE pattern was identified, with minor variations over time, with spa type 2, sequence type 5, SCCmec type II, agr type 2 and the presence of the enterotoxin genes seg and sei, the c-haemolysin variant gene hlg-v and the leukocidin lukE-lukD genes. In addition, the isolates showed antimicrobial resistance to b-lactams, macrolides, chloramphenicol and imipenem, and susceptibility to gentamicin, rifampicin, trimethoprim-sulphamethoxazole and vancomycin. Following its appearance in 1997, this clone spread within the hospital, and is now present in most of the hospital units and wards.
Russian Open Medical Journal, 2016
Aim-The present study aimed to detect mecA and staphylococcal cassette chromosome mec (SCCmec) types in methicillinresistant Staphylococcus aureus (MRSA) isolates obtained from various clinical samples in two university hospitals. It was also aimed to make comparison amongst the isolates. Materials and Methods-A total of 99 MRSA strains isolated from various clinical samples between 2011-2015 were included in the study. Bacterial deoxyribonucleic acid (DNA) was extracted from Staphylococcus aureus strains using GF-1 DNA extraction Kit (Vivantis, Malaysia). mecA gene were detected, and SCCmec cassette types were determined by multiplex polymerase chain reaction (PCR) first, and following specific PCR. Specific MRSA strains such as COL type I, PER3 type Ia, and HU25 type IIIa were used as the quality control strains for optimization of multiplex PCR. The amplification products were electrophoresed using agarose gel electrophoresis in TAE buffer (mixture of tris base, acetic acid and ethylenediaminetetraacetic acid). Results-mecA gene was detected in 60 Staphylococcus aureus isolates, and these were identificated as MRSA. Amongst the MRSA strains, SCCmec type III was the most frequent cassette type (42 isolates, 70.0%). SCCmec type I was detected in 27 isolates (45.0%), type II was in 26 isolates (43.3%), and type V in 23 isolates (38.3%). Conclusion-In the present study, the most frequent cassette was detected as SCCmec type III in concordance with the studies conducted in Turkey and in some regions in the world. In conclusion, determination of epidemiological and molecular characteristics of MRSA strains has critical importance because of the difficulties in the treatment and of the nosocomial infections and epidemics they caused. The data obtained would contribute to the preventions in terms of epidemiology.
Phenotypic and Genotypic detection of local MRSA isolates
Zagazig Journal of Pharmaceutical Sciences
Methicillin-Resistant Staphylococcus aureus (MRSA) infections have become a global health problem particularly in developing countries. MRSA strains are characterized by rapid resistance against different groups of antibiotics.The current study was aimed to identify MRSA isolates phenotypically by disk diffusion method and genoytypically by PCR. A total of 200 clinical specimens were collected from Zagazig University Hospitals and El-Ahrar Educational Hospital in Zagazig, Egypt, and identified biochemically. Out of these specimens, 117 isolates were identified as MRSA by disk diffusion method (DDM); only 114 of these isolates were identified as MRSA by PCR amplification of mecA gene. The study revealed that PCR was more accurate and rapid than other conventional methods and it is considered the gold standard method for MRSA detection to avoid false positive identification of MRSA.
Journal of Clinical Microbiology, 2011
Twenty-three nasal swab samples that tested positive for methicillin-resistant Staphylococcus aureus (MRSA) on initial testing by the BD GeneOhm MRSA assay (BD-MRSA PCR; BD GeneOhm, San Diego, CA) were culture positive only for methicillin-susceptible S. aureus (MSSA) from an enrichment broth. The 23 recovered isolates were confirmed as MSSA by a variety of phenotypic methods, including the BD Phoenix automated microbiology system (BD Diagnostics, Sparks, MD), oxacillin screening agar (BD Diagnostics), BBL CHROMagar MRSA (BD Diagnostics), and a PBP2 assay (Denka Seiken Co., Tokyo, Japan); susceptibilities were determined by using Mueller-Hinton agar with oxacillin. All were positive by nuc PCR, specific for S. aureus, but negative for mecA with one exception. Isolates were characterized by using multiplex PCR methodology to determine structural types and variants (SCCmec typing); additional PCRs were performed for the detection of the ccr and mec complexes, the junkyard regions as well as the Panton-Valentine leukocidin. Pulsed-field gel electrophoresis was used to determine clonality. One phenotypic MSSA isolate contained an intact SCCmec. Twelve MSSA isolates tested positive for MRSA by the BD-MRSA PCR because of amplification of the mec priming site flanking the SCC insertion point, although these isolates lacked mecA. The 10 remaining isolates were not MRSA and tested as MSSA by phenotypic and genotypic assays. In our patient population, diagnostic and surveillance testing and subsequent infection control practices may be impacted by the frequency of these excision events when using the BD-MRSA PCR for MRSA detection.