Identification Of Methicillin-resistant Staphylococcus Aureus Research Articles

Multiplex Digital PCR-Based Development and discussion of the Detection of Genetic Association Between Staphylococcus aureus and mecA.

Methicillin-resistant Staphylococcus aureus (MRSA) is a predominant nosocomial infection-causing bacteria. The aim of this study was to develop a novel single-bacteria multiplex digital PCR assays (SMD-PCR), which is capable of simultaneously detecting and discriminating Methicillin-sensitive Staphylococcus aureus (MSSA) and MRSA. This protocol employed TaqMan probes to detect SAOUHSC_00106 and mecA genes, with the latter being linked to methicillin resistance. A total of 72 samples from various specimen types were evaluated. The accuracy rates for the sputum samples, pus samples, swab samples, ear secretion samples, and catheter samples were 94.44%, 100%, 92%, 100%, and 100%, respectively. Our results showed that the clinical practicability of SMD-PCR has applicability to the rapid detection of MRSA without DNA extraction or bacterial culture, and can be utilized for the rapid detection of Staphylococcus aureus and the timely identification of MRSA in clinical samples, thereby providing an advanced platform for the rapid diagnosis of clinical MRSA infection.

Rapid identification of MRSA directly from sterile body fluids by co-magnetic bead enrichment and MALDI-TOF mass spectrometry

As a result of the extensive use of antibiotics, methicillin-resistant Staphylococcus aureus (MRSA) has emerged, leading to serious clinical and epidemiological problems. This study established a rapid and accurate method for detection of MRSA in clinical samples. The MRSA detection procedure involved a magnetic separation technique and Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), and the characteristic peaks of proteins were compared to achieve the detection of MRSA. We treated PBS, blood and cerebrospinal fluid with MRSA, and identified it after short-term culture. The time and detection limit for identifying MRSA were determined. At the same time, we used the method to detect different proportions of mixed bacteria. The results revealed that the enrichment efficiency of Amp-MBs for MRSA in PBS, blood and cerebrospinal fluid was greater than 95 %, 80.95 % and 83.6 %, respectively. The whole detection process could be completed within 1.5 h. The negative and positive percent agreement of MRSA detection were 83 % and 95 %, respectively. In mixed bacterial samples, bacteria can be detected when the proportion of MRSA is greater than 50 %. Overall, this study provides an effective method for bacterial preconcentration and detection, which has high potential for rapid and sensitive diagnosis of MRSA infection

Prediction of methicillin-resistant Staphylococcus aureus and carbapenem-resistant Klebsiella pneumoniae from flagged blood cultures by combining rapid Sepsityper MALDI-TOF mass spectrometry with machine learning

This study investigated combination of the Rapid Sepsityper Kit and a machine learning (ML)-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) approach for rapid prediction of methicillin-resistant Staphylococcus aureus (MRSA) and carbapenem-resistant Klebsiella pneumoniae (CRKP) from positive blood culture bottles. The study involved 461 patients with monomicrobial bloodstream infections. Species identification was performed using the conventional MALDI-TOF MS Biotyper system and the Rapid Sepsityper protocol. The data underwent preprocessing steps, and ML models were trained using preprocessed MALDI-TOF data and corresponding labels. The interpretability of the model was enhanced using SHapely Additive exPlanations values to identify significant features. In total, 44 S. aureus isolates comprising 406 MALDI-TOF MS files and 126 K. pneumoniae isolates comprising 1249 MALDI-TOF MS files were evaluated. This study demonstrated the feasibility of predicting MRSA among S. aureus and CRKP among K. pneumoniae isolates using MALDI-TOF MS and Sepsityper. Accuracy, area under the receiver operating characteristic curve, and F1 score for MRSA/methicillin-susceptible S. aureus were 0.875, 0.898 and 0.904, respectively; for CRKP/carbapenem-susceptible K. pneumoniae, these values were 0.766, 0.828 and 0.795, respectively. In conclusion, the novel ML-based MALDI-TOF MS approach enables rapid identification of MRSA and CRKP from flagged blood cultures within 1 h. This enables earlier initiation of targeted antimicrobial therapy, reducing deaths due to sepsis. The favourable performance and reduced turnaround time of this method suggest its potential as a rapid detection strategy in clinical microbiology laboratories, ultimately improving patient outcomes.

Simple and Rapid Discrimination of Methicillin-Resistant Staphylococcus aureus Based on Gram Staining and Machine Vision.

Methicillin-resistant Staphylococcus aureus (MRSA) is a clinical threat with high morbidity and mortality. Here, we describe a new simple, rapid identification method for MRSA using oxacillin sodium salt, a cell wall synthesis inhibitor, combined with Gram staining and machine vision (MV) analysis. Gram staining classifies bacteria as positive (purple) or negative (pink) according to the cell wall structure and chemical composition. In the presence of oxacillin, the integrity of the cell wall for methicillin-susceptible S. aureus (MSSA) was destroyed immediately and appeared Gram negative. In contrast, MRSA was relatively stable and appeared Gram positive. This color change can be detected by MV. The feasibility of this method was demonstrated in 150 images of the staining results for 50 clinical S. aureus strains. Based on effective feature extraction and machine learning, the accuracies of the linear linear discriminant analysis (LDA) model and nonlinear artificial neural network (ANN) model for MRSA identification were 96.7% and 97.3%, respectively. Combined with MV analysis, this simple strategy improved the detection efficiency and significantly shortened the time needed to detect antibiotic resistance. The whole process can be completed within 1 h. Unlike the traditional antibiotic susceptibility test, overnight incubation is avoided. This new strategy could be used for other bacteria and represents a new rapid method for detection of clinical antibiotic resistance. IMPORTANCE Oxacillin sodium salt destroys the integrity of the cell wall of MSSA immediately, appearing Gram negative, whereas MRSA is relatively stable and still appears Gram positive. This color change can be detected by microscopic examination and MV analysis. This new strategy has significantly reduced the time to detect resistance. The results show that using oxacillin sodium salt combined with Gram staining and MV analysis is a new, simple and rapid method for identification of MRSA.

Detecting the performance of methicillin-resistant Staphylococcus aureus by a molecular diagnostic assay in positive blood culture: Influence of coexistence of mecA-positive bacteria and diversity in orfX-SCCmec junction region in methicillin-susceptible S. aureus

BackgroundIn blood cultures that test positive for staphylococcal bacteria, rapid identification of methicillin-resistant Staphylococcus aureus (MRSA) or methicillin-susceptible Staphylococcus aureus (MSSA) by molecular assay is useful for appropriate antimicrobial treatment of bloodstream infections. Although the Xpert MRSA/SA BC assay is widely available in clinical settings in Japan, its efficacy has not yet evaluated thoroughly. MethodsWe retrospectively studied 100 blood culture cases positive for S. aureus at Sapporo Medical University Hospital between March 2019 and May 2022. Cycle threshold (CT) values for target genes from the Xpert MRSA/SA BC assay were compared to phenotypic results. Genotyping and genetic analysis of the orfX-SCCmec junction region was performed for selected isolates. ResultsWe analyzed 25 and 75 isolates assigned to MRSA and MSSA, respectively, using the Xpert MRSA/SA BC assay. Of these, 99 isolates from agar cultures showed compatible susceptibility to oxacillin. One genetically misidentified case of MRSA was found to be caused by the mixed growth of MSSA and methicillin-resistant S. hominis on agar culture. Of the 73 MSSA with pure growth on agar culture, 45 (61.6%) were found to be orfX-SCCmec-positive, spa-positive, and mecA-negative in this assay. These MSSA belong to diverse spa and coa types. ConclusionThe Xpert MRSA/SA BC assay accurately identified MRSA and MSSA in positive blood cultures. However, over half of the MSSA isolates showed positive results for orfX-SCCmec, presumably due to genetic diversity in the orfX-associated region of MSSA. Therefore, the coexistence of MSSA and mecA-harboring coagulase-negative staphylococci may cause confusion about identification of MRSA.

Pathogenic Role and Antibiotic Resistance of Methicillin-Resistant Staphylococcus aureus (MRSA) Strains Causing Severe Community-Acquired Pneumonia in Vietnamese Children.

In recent years, the pathogenic role and antibiotic resistance of methicillin-resistant Staphylococcus aureus (MRSA) strains causing severe community-acquired pneumonia (CAP) have received increasing attention in clinical practice. The aim of this study was to determine the rate of isolates of MRSA strains causing severe CAP in children and to assess their level of antibiotic resistance. The study design was cross-sectional. Children with severe CAP were sampled by nasopharyngeal aspiration for the culture, isolation, and identification of MRSA. Antimicrobial susceptibility testing was performed using the gradient diffusion method to determine the minimum inhibitory concentration (MIC) of antibiotics. Results: MRSA was identified as the second leading cause of severe CAP in Vietnamese children. The rate of isolates of S. aureus was 41/239 (17.5%), of which most were MRSA, at 32/41 (78.0%). MRSA strains were completely non-susceptible to penicillin (100%), more resistant to clindamycin and erythromycin, less sensitive to ciprofloxacin and levofloxacin, and fully susceptible to vancomycin and linezolid, with a 32-fold decreased MIC90 for vancomycin (0.5 mg/L) and a 2-fold decreased MIC90 for linezolid (4 mg/L). Therefore, vancomycin and linezolid may be appropriate options for severe CAP identified by MRSA.

The role of food in the spread of the Methicillin – resistant Staphylococcus aureus (MRSA)

Methicillin-resistant Staphylococcus aureus (MRSA) are important human pathogen. It is present in a wide range of animal species (pigs, cows, sheep, and chickens) even in healthy animals. Identification of MRSA in foods has led to concerns about the role of livestock in the epidemiology of MRSA infections in human. This review focuses on the spread of MRSA in different types of food and its antimicrobial resistance to the most widely used antimicrobials in human and veterinary medicine. The results of review indicates that livestock is major source of MRSA in humans and mainly transmitted to humans through contaminated food. The actual prevalence of MRSA in animals and food as well as impact to the human health is not well understood. It is clearly that MRSA is an important pathogen to veterinary medicine and human health which requires more and in-depth research to understand the hazard and take effective measures to limit it.

CRISPR/Cas12a coupling with RPA and MNPs for rapid and visualized identification of methicillin-resistant Staphylococcus aureus

Methicillin resistant Staphylococcus aureus (MRSA), as one of drug-resistant bacteria, severely affects public health. Rapid and accurate identification of MRSA is essential to prevent the spread of infections and guide effective treatment. Current methods for MRSA detection suffer from the disadvantages of time consuming or sophisticated instrument requirements, which hinder their practical application in resource-limited areas as well as for on-site detection. Herein, we develop a rapid, specific, ultrasensitive colorimetric assay based on the recombinase polymerase amplification (RPA) and magnetic nanoparticles (MNPs) assisted CRISPR/Cas12a for the detection of the mecA gene in MRSA bacteria. This method for detecting mecA gene has a good linear correlation from 1 to 1 * 10^6 aM with a low detection limit of 0.2 aM. Furthermore, this method has been successfully applied for detecting mecA gene from the patients infected with MRSA and the results are in good consistence with the culture-based and qPCR-based methods. The developed method can realize the rapid and accurate identification of MRSA within 2 h via the color change observable by naked eye, which is expected to have great prospects in future practical point-of-care testing (POCT) applications for drug-resistant bacteria identification.

Visual Assay for Methicillin-Resistant Staphylococcus aureus Based on Rolling Circular Amplification Triggering G-Quadruplex/Hemin DNAzyme Proximity Assembly.

Nowadays, infections caused by methicillin-resistant Staphylococcus aureus (MRSA) have constituted a new challenge for anti-infective treatment. Precise identification and rapid clinical diagnostics of MRSA from other methicillin-sensitive strains entail assays with robust diagnostic efficiency and simple operation steps. Sensitive detection of MecA gene is promising to indicate MRSA infection, but it is challenged by the lack of isothermal and simple strategies. A visual assay based on isothermal rolling circular amplification and G-quadruplex/hemin (G4/hemin) DNAzyme proximity assembly was proposed for the immediate, efficient, and cost-effective detection of MecA in simple operation steps and in a single tube. The presence of MecA specifically drove the formation of circular templates, which further triggered isothermal amplification. The amplified product offered abundant binding sites for DNA-grafted hemin probes to form a novel proximity-assembled G4/hemin DNAzyme structure for colorimetric changing diagnosis. This tandem-repeated novel DNAzyme possessed higher catalytic activity and a lower background signal than traditional G4/hemin DNAzyme, ensuring sensitive discrimination of MRSA (limit of detection: 9.6 pM). Assay stability and antimatrix interference capability enable clinical application, which shows compared diagnostic ability with classic methods (100% sensitivity and 100% specificity) but possesses more simplified procedures and shorter turnaround time (<6 h). This colorimetric strategy in a nonsite-specific and hypersensitive manner holds foreseeable prospects in clinical diagnostic and research applications.

Molecular Characterization of Community- and Hospital- Acquired Methicillin-Resistant Staphylococcus aureus Isolates during COVID-19 Pandemic.

Methicillin-resistant Staphylococcus aureus (MRSA) is a drug-resistant superbug that causes various types of community- and hospital-acquired infectious diseases. The current study was aimed to see the genetic characteristics and gene expression of MRSA isolates of nosocomial origin. A total of 221 MRSA isolates were identified from 2965 clinical samples. To identify the bacterial isolates, the clinical samples were inoculated on blood agar media plates first and incubated at 37 °C for 18-24 h. For further identification, the Gram staining and various biochemical tests were performed once the colonies appeared on the inoculated agar plates. The phenotypic identification of antibiotic susceptibility patterns was carried out using Kirby-Bauer disk diffusion method by following the Clinical and Laboratory Standards Institute (CLSI) 2019 guidelines. The biofilm-producing potentials of MRSA were checked quantitatively using a spectrophotometric assay. All strains were characterized genotypically by SCCmec and agr typing using the specific gene primers. Furthermore, a total of twelve adhesion genes were amplified in all MRSA isolates. MRSA was a frequently isolated pathogen (44% community acquired (CA)-MRSA and 56% hospital acquired (HA)-MRSA), respectively. Most of the MRSA isolates were weak biofilm producers (78%), followed by moderate (25%) and strong (7%) biofilm producers, respectively. Prominent adhesion genes were clfB (100%), icaAD (91%), fib (91%), sdrC (91%) followed by eno (89%), fnbA (77%), sdrE (67%), icaBC (65%), clfA (65%), fnbB (57%), sdrD (57%), and cna (48%), respectively. The results of the current study will help to understand and manage the spectrum of biofilm-producing MRSA-associated hospital-acquired infections and to provide potential molecular candidates for the identification of biofilm-producing MRSA.

Derivation and Validation of a Risk Score for Methicillin-Resistant Staphylococcus aureus Bloodstream Infection.

Compared with methicillin sensitive Staphylococcus aureus (MSSA), the prognosis of patients with methicillin resistant Staphylococcus aureus (MRSA) bloodstream infection is poor. Therefore, the construction of MRSA and MSSA identification model has certain value for the selection of antibiotics and treatment outcome control. This study aimed to derive and validate a simple risk prediction model for MRSA bloodstream infection in Chinese patients. Three hundred and thirty-five patients with Staphylococcus aureus (S. aureus) bloodstream infection were retrospectively analyzed and divided into three groups. The first group was used for the risk score derivation (n = 163), the second group was used for internal validation (n = 80), and the third group was used for external validation (n = 92). According to the odds ratio (OR) obtained from multivariate logistic regression, the risk prediction model for MRSA bloodstream infection was established, and the prediction efficiency of the model in three cohorts were evaluated. Hospital stay before BSI ≥ 7 days, hospital acquired BSI, infection source ≥ 2 sites, indwelling gastric tube before BSI and carbapenems used before BSI and after admission were independent influencing factors of MRSA in the derivation group, the above influencing factors were scored 3, 5, 4, 3, and 3, respectively. The derivation, internal and external validation groups showed adequate discrimination (the AUCs were 0.788, 0.780, and 0.742, respectively) and good calibration (H-L tests were χ2 = 3.896, p = 0.306; χ2 = 4.221, p = 0.298; and χ2 = 3.974, p = 0.352, respectively). The risk scores were further divided into very low-risk (score 0 - 3), low-risk (score 4 - 7), high-risk (score 8 - 12), and very high-risk (score ≥ 13) layers. The simple risk score model for predicting MRSA bloodstream infection has good predictive effect, high predictive accuracy, and good clinical applicability, which can help clinicians choose sensitive antibiotics and reduce the adverse prognosis of patients.

Rapid identification of methicillin-resistant Staphylococcus aureus by MALDI-TOF MS: A meta-analysis.

Invasive infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are associated with high mortality and morbidity. The sooner the pathogen is determined, the better it is beneficial to patient. However, routine laboratory inspections are time-consuming and laborious. A thorough research was conducted in PubMed and Web of Science (until June 2021) to identify studies evaluating the accuracy of MRSA identification by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). STATA 15.0 software was used to analyze the pooled results of sensitivity, specificity, and 95% confidence intervals (CI). The summary receiver operating characteristic curves (SROC) and area under the curve (AUC) were utilized to show the overall performance of MALDI-TOF MS. Fifteen studies involving 2471 isolates were included in this study after the final selection in this meta-analysis. Using the random effects model forest plot to summarize the overall statistics, the sensitivity of MALDI-TOF MS for identifying MRSA was 92% (95% CI: 81%-97%), and the specificity was 97% (95% CI: 89%-99%). In the SROC curve, the AUC reached 0.99 (95% CI: 97%-99%). Deeks' test showed no significant publication bias in this meta-analysis. Compared with clinical reference methods, MALDI-TOF MS identification of MRSA shows a higher degree of sensitivity and specificity.

Pet animals as reservoirs for spreading methicillin-resistant Staphylococcus aureus to human health.

Methicillin-resistant Staphylococcus aureus (MRSA) is a strain of pathogenic bacteria that is a major problem in the world's health. Due to their frequent interaction with humans, pets are one of the main risk factors for the spread of MRSA. The possibility for zoonotic transmission exists since frequently kept dogs and cats are prone to contract MRSA and act as reservoirs for spreading MRSA. The mouth, nose, and perineum are the primary locations of MRSA colonization, according to the findings of MRSA identification tests conducted on pets. The types of MRSA clones identified in cats and dogs correlated with MRSA clones infecting humans living in the same geographic area. A significant risk factor for the colonization or transmission of MRSA is human-pet contact. An essential step in preventing the spread of MRSA from humans to animals and from animals to humans is to keep hands, clothing, and floor surfaces clean.

Identification and Antibiotic Resistance Profile of Biofilm-forming Methicillin Resistant Staphylococcus aureus (MRSA) Causing Infection among Orthopedic Wound Patients

Background and Objectives: The biofilm-forming ability of Methicillin-Resistant Staphylococcus aureus(MRSA) strains have demonstrated the involvement of MRSA biofilm in antibiotic resistance, recalcitrant and persistent infections in humans. Despite a deeper understanding of the biofilm-forming ability of MRSAstrain, it is still essential to extend the research on the identification and antibiotic resistance profile of biofilm-forming MRSA causing infection among orthopedic wound patients.&#x0D; Methodology: A total of three hundred and thirty (303) patient-isolate of non-repeatable Staphylococcus aureus strains were obtained during the period of 2021 until 2022 from fracture and post-surgical orthopedic wound patients with wound duration &gt;2months at the National Orthopedic Hospital, Enugu (NOHE). S. aureus were identified using conventional microbiological cultures Technique followed by confirmation of MRSA strain through Brilliance MRSA 2 Agar. Antibiotic Susceptibility testing (AST) of biofilm-forming MRSA was performed using the Kirby–Bauer disk diffusion method and the results were interpreted using the Clinical Laboratory Standard Institute (CLSI) zone diameter breakpoints. Multidrug Resistance (MDR) was determined for biofilm-forming MRSA.&#x0D; Result:Of the 303 isolate of S. aureus, MRSA strain accounted 86(28.4 %) and 78(25.7 %) from post-surgical wound and fracture wound respectively while biofilm forming MRSA was identified in 101(33.4%) MRSA strain consisting of high proportion 66(21.8 %) fromPost-surgical wound followed by fracture wound samples recording 35(11.6 %). Association between MRSA production and biofilm formation was considered statistically significant at P&lt; .05. The proportion of biofilm-forming MRSA resistance to β-lactam accounted 71.4-100%, macrolide resistance recorded 65.7-92.4 %, lincosamideresistance 74.3-100 %, glycopeptide resistance proportion ranged from 62.8-100 % while low level of resistance to fluoroquinolones 19.7-42.9 % and Aminoglycoside 8.6-10.6 % was observed. Biofilm-forming MRSA isolate were MDR to one or more antibiotic antimicrobial agents in at least three categories withMDRIndex range ≥ 0.3 but majority of the isolate were 91.4% and 100% susceptible to Gentamicin and Imipenem.&#x0D; Conclusion: The invitro expression of biofilm formation among MRSA strain and their antibiotic resistance profile in this study makes them a potential threat and challenging pathogens with the ability to cause persistent infections in humans, especially among orthopedic wound patients. Thus the development of an antimicrobial stewardship program and regular detection of biofilm production is needed for timely intervention while judicious use of Imipenem and Gentamicin as a drug of choice for effective treatment of infection caused by biofilm-forming MRSA among orthopedic patients will avert the severity of infection. Further research of these sort should investigate the genotyping expression of a biofilm gene variant in other human diseases, different bacteria species, and orthopedic medical implant devices.

Performance of a Machine Learning-Based Methicillin Resistance of Staphylococcus aureus Identification System Using MALDI-TOF MS and Comparison of the Accuracy according to SCCmec Types.

The prompt presumptive identification of methicillin-resistant Staphylococcus aureus (MRSA) using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) can aid in early clinical management and infection control during routine bacterial identification procedures. This study applied a machine learning approach to MALDI-TOF peaks for the presumptive identification of MRSA and compared the accuracy according to staphylococcal cassette chromosome mec (SCCmec) types. We analyzed 194 S. aureus clinical isolates to evaluate the machine learning-based identification system (AMRQuest software, v.2.1, ASTA: Suwon, Korea), which was constructed with 359 S. aureus clinical isolates for the learning dataset. This system showed a sensitivity of 91.8%, specificity of 83.3%, and accuracy of 87.6% in distinguishing MRSA. For SCCmec II and IVA types, common MRSA types in a hospital context, the accuracy was 95.4% and 96.1%, respectively, while for the SCCmec IV type, it was 21.4%. The accuracy was 90.9% for methicillin-susceptible S. aureus. This presumptive MRSA identification system may be helpful for the management of patients before the performance of routine antimicrobial resistance testing. Further optimization of the machine learning model with more datasets could help achieve rapid identification of MRSA with less effort in routine clinical procedures using MALDI-TOF MS as an identification method.

Wound swabs versus biopsies to detect methicillin resistant Staphylococcus aureus in experimental equine wounds.

To compare: (1) the load and diversity of cultivatable bacterial species isolated from tissue biopsies with cultures from surface swabs, and (2) the ability of each technique to detect methicillin-resistant Staphylococcus aureus (MRSA) in a model of MRSA-infected equine wounds. Experimental in vivo study. Three light-breed adult horses. Four 2.5 × 2.5cm full-thickness skin wounds were created on the dorsolateral aspect of each forelimb. Five days later, each wound was inoculated with a pure culture of MRSA (ATCC 43300). One hundred microlitres of 0, 5 × 108 , 5 × 109 or 5 × 1010 colony forming units (CFU)/ml was used to inoculate each wound. Surface swabs (Levine technique) and tissue biopsy samples (3 mm punch biopsy) were obtained at 2, 7, 14, and 21 days after inoculation. Quantitative aerobic culture was performed using routine clinical techniques. A similar bacterial profile was identified from the culture of each wound-sampling technique and there was moderate correlation (R=0.49, P < .001) between the bacterial bioburdens. Agreement was fair (κ=0.31; 95% CI, 0.129-0.505) between the sampling techniques in identification of MRSA. Methicillin-resistant Staphylococcus aureus was isolated more frequently (P=.016) from cultures of tissue biopsies (79%; 76/96) than from surface swabs (62%; 60/96). Bacterial load and diversity did not differ between sampling techniques but MRSA was detected more often from the cultures of tissue biopsies. Tissue biopsy should be preferred to culture swab in wounds where MRSA is suspected.

Clinical relevance of molecular testing methods in the diagnosis and guidance of therapy in patients with staphylococcal empyema: a systematic review and meta-analysis.

BackgroundEfficient detection tools for determining staphylococcal pleural infection are critical for its eradication. The objective of this meta-analysis was to assess the diagnostic utility of nucleic acid amplification tests (NAAT) in suspected empyema cases to identify staphylococcal strains and avoid unnecessary empiric methicillin-resistant Staphylococcus aureus (MRSA) therapy.MethodsFrom inception to July 24, 2021, relevant records were retrieved from PubMed, Embase, Scopus, Web of Science, and the Cochrane Library. The quality of studies was determined using the QUADAS-2 tool. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and hierarchical summary receiver operating characteristic (HSROC) curve for NAAT’s diagnostic performance were evaluated using an HSROC model.ResultsEight studies comprising 424 samples evaluated NAAT accuracy for Staphylococcus aureus (SA) identification, while four studies comprising 317 samples evaluated methicillin-resistant Staphylococcus aureus (MRSA) identification. The pooled NAAT summary estimates for detection of both SA (sensitivity: 0.35 (95% CI 0.19–0.55), specificity: 0.95 (95% CI 0.92–0.97), PLR: 7.92 (95% CI 4.98–12.59), NLR: 0.44 (95% CI 0.14–1.46), and DOR: 24.0 (95% CI 6.59–87.61) ) and MRSA (sensitivity: 0.45 (95% CI 0.15–0.78), specificity: 0.93 (95% CI 0.89–0.95), PLR: 10.06 (95% CI 1.49–67.69), NLR: 0.69 (95% CI 0.41–1.15), and DOR: 27.18 (95% CI 2.97–248.6) ) were comparable. The I 2 statistical scores for MRSA and SA identification sensitivity were 13.7% and 74.9%, respectively, indicating mild to substantial heterogeneity. PCR was frequently used among NAA tests, and its diagnostic accuracy coincided well with the overall summary estimates. A meta-regression and subgroup analysis of country, setting, study design, patient selection, and sample condition could not explain the heterogeneity (meta-regression P = 0.66, P = 0.46, P = 0.98, P = 0.68, and P = 0.79, respectively) in diagnostic effectiveness.ConclusionsOur study suggested that the diagnostic accuracy of NAA tests is currently inadequate to substitute culture as a principal screening test. NAAT could be used in conjunction with microbiological culture due to the advantage of faster results and in situations where culture tests are not doable.

Prevalence of Meticillin Resistance Staphylococcus Aureus in Patients with Lower Respiratory Tract Infections

Background: Lower respiratory tract infection (LRTIs) is an emerging and threatening disease of both adults and children. Methicillin resistant Staphylococcus aureus (MRSA) remains a life threatening pathogens that may colonize the lungs and cause Staphylococcal related lower respiratory tract infection. The aim of this study was to determine the prevalence and risk factors associated with MRSA infection among individuals with lower respiratory tract infections in a community setting. Method: A structured questionnaire consisting of demographic characteristics, antibiotic usage, social life habits were administered to 152 participants, comprising of 80 males and 72 females. The subjects were selected based on non- hospitalization for the past six months. Sputum samples were collected and cultured unto Mannitol Salt agar. The Staphylococcus aureus isolates were sub-cultured unto Chromagar MRSA for MRSA identification. The isolates were subjected to antibiotic susceptibility testing, using disc diffusion method. Result: The MRSA were highly resistant to Ampiclox (96.2%), Amoxcillin (92.3%), Rifampicin and Streptomycin (80.8%), Norfloxacin (76.9%), Erythromycin and Chroramphenicol (69.2%), and Levofloxacin (65.4%). Conclusion: This study showed that MRSA is implicated in LRTIs and is brought about by improper therapy and lack of awareness.

Prospective surveillance of colonization and disease by methicillin-resistant Staphylococcus aureus (MRSA) at a European pediatric cancer center

PurposeChildren and adolescents undergoing treatment for cancer or allogeneic hematopoietic cell transplantation are at increased risk for methicillin-resistant Staphylococcus aureus (MRSA). We therefore examined the occurrence and outcome of MRSA colonization and infection in patients of a large European pediatric cancer center.MethodsIn a prospective observational cohort study conducted between 2007 and 2018, nasopharyngeal swabs for culture of MRSA were obtained from all admitted patients. The primary endpoint of the study was the colonization rate over time. Secondary endpoints included genetic relatedness of isolates, time burden of isolation measures, and results of decolonization efforts.ResultsDuring the study period, MRSA screening identified 34 colonized patients (median age: 10 years; range: 0–21) without trends over time. MRSA colonization was associated with the presence of classical risk factors. There was no molecular evidence of patient-to-patient transmission. A standard MRSA eradication regimen led to a lasting eradication of the organism in 26 of 34 patients. MRSA infection occurred in two patients with no associated fatalities.ConclusionProspective monitoring revealed low rates of MRSA colonization and infection at our center. These low rates and the absence of patient-to-patient transmission support the effectiveness of the management bundle of MRSA identification, isolation, and decolonization.

Comparison of Different Phenotypic Methods Including E-Test, Cefoxitin and Oxacillin Disk Diffusion for Detection of Methicillin Resistant Staphylococcus aureus

Introduction: Methicillin-Resistant Staphylococcus aureus (MRSA) has spread throughout the world as a hospital and communityacquired illness. Although a variety of strategies have been employed, laboratory identification of MRSA remains a difficulty. Aim: To examine several phenotypic approaches for accuracy results, with an (Epsilometer) E-test based method serving as the gold standard for MRSA identification. Materials and Methods: A prospective observational study was conducted in the Microbiology department of Santosh Medical College, Ghaziabad, Uttar Pradesh, India, from August 2020 to July 2021. Total of 384 isolates S.aureus were identified by using the required samples including pus, swab, blood, wound and urine, etc., which were collected from the Microbiology department and the comparison was done between E-test serving as the gold standard for MRSA identification with Cefoxitin Disk Diffusion (CDD)/ Oxacillin Disk Diffusion method (ODD). The diagnostic kit for using E-Test in collected samples was purchased from Himedia Laboratries Pvt., Ltd., Mumbai, India (EM0065). The data was calculated by using MS-Excel. Results: A total of 113 strains were revealed to be MRSA in clinical specimens out of 384 isolated S.aureus. The gold standard method was chosen to be the E-Test, which had found a high sensitivity of 79.8% and a specificity of 94.2%. Compared to the cefoxitin/oxacillin disc diffusion method, isolates including MRSA were highly susceptible to Tiecoplanin and Linezolid. Conclusion: The present study concludes that E-Test (strip) method is a high sensitivity and highly specific for detecting MRSA in comparison to other disk methods used in this study. Due to less number of sample size and lesser time period more studies are needed to establish this fact.