Methicillin-resistant Staphylococcus Aureus Samples Research Articles

New insights: mupirocin resistance among methicillin-resistant Staphylococcus aureus (MRSA) infection in southern Indian region

: Methicillin-resistant (MRSA) remains to be the most concerned pathogen with enhanced multi-drug resistance in clinical set-ups. With an immediate need to control MRSA infection, there is a steep rise in the use of mupirocin as a decolonization regime.: A total of 65 MRSA samples were analysed in the present study. infection identified by standard conventional phenotypic methods. The antibiotic susceptibility pattern of mupirocin (5 μg/ml) was found using Kirby Bauer’s disc diffusion method and the minimum inhibitory concentration (MIC) determined using MIC E-test strips of mupirocin.: All the bacterial strains presented with MIC value less than 4 μg/ml, 23 isolates falls in the range of 0.05 μg/ml and 0.19 μg/ml, 12 strains MIC ranged between 0.125 and 0.640 μg/ml. However, five MRSA isolates showed no zone against mupirocin E-strip.: In present study, 92% of isolates were sensitive to mupirocin, this gives hope that mupirocin can be promising in the elimination of MRSA strains, a major concern in clinical practice. Also, the use of 5µg mupirocin discs is economical as compared to mupirocin E-strips, mupirocin discs can be used in a low resourceful clinical setups. However, our study revealed no difference in sensitivity for both the E-strip and disc method.

Assessing Mupirocin Resistance in MRSA Isolates in Hospitals in Cleveland, OH and Detroit, MI

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a common pathogen responsible for nosocomial and community-acquired infections with high morbidity and mortality1. MRSA nasal colonization is a major risk factor for developing infection in the hospital setting2,3. Decolonization of MRSA carriers is a strategy to decrease recurrence or to prevent new MRSA infections3,4. Decolonization with nasal mupirocin 2% and chlorhexidine baths has been shown to decrease the risk of MRSA infection after hospital discharge3. Mupirocin is an RNA synthetase inhibitor with activity against MRSA5. Resistance of MRSA isolates to mupirocin has been described previously6. As topical disinfectants play a crucial role in prevention of MRSA infection in a variety of settings, it is important to monitor the emergence of resistance. The goal of this study was to determine the prevalence of mupirocin resistance among MRSA samples isolated from two different regions in the United States (U.S). Methods: Our study had a total of 474 MRSA samples that were obtained from hospitals in Detroit, MI (287 samples) and Cleveland, OH (187 samples). After whole genome sequencing using NextSeq (Illumina Inc., CA) platform the data was analyzed using ResFinder 4.1, to identify antimicrobial resistance which can be either acquired or chromosomally mediated mutations. To visualize the presence of genes of interest the resistance genes were tallied on a spread sheet. Results: Mupirocin resistance gene was detected in five of 287 (1.74%) MRSA samples from the Detroit hospitals, all of which were associated with the mupA gene. Samples collected from the Cleveland area hospital demonstrated mupirocin resistance in seven samples of 187 (3.74%), all associated again with the mupA gene. One sample from the Detroit group showed resistance to both mupirocin and chlorhexidine. Conclusions: Prevalence of mupirocin resistance gene varied between the two hospital locations. Resistance to mupirocin has been documented in association with mutations in the mupA gene as well as chromosomal point mutations that can lead to either low or high-level resistance7,8. Although the mechanisms are not fully clear, mupA gene has been associated with high-level resistance9. Mupirocin resistance among MRSA isolates has increased over time9. MRSA infections remain an important etiology of nosocomial and community-acquired infections and common practice to combat this issue is universal decolonization with mupirocin10. It is critical to understand and monitor for development of mupirocin resistance as mupirocin remains one of the most effective tools to prevent invasive infection with MRSA in many patient populations.

Assessing chlorhexidine resistance in MRSA isolates from hospitals in Cleveland, OH and Detroit, MI

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common causes of procedure-related, skin, and soft-tissue infections. Hospitalized patients who are colonized with MRSA are at a higher risk of developing invasive infections after discharge. Chlorhexidine, an antiseptic/disinfectant, has been used to reduce carriage and prevent infections in these patients. Studies have shown chlorhexidine resistance among MRSA strains. Chlorhexidine resistance is associated with qac genes, which encode multidrug efflux pumps that increase bacterial tolerance to disinfectant agents. The global distribution and prevalence of qacA and qacB genes are highly variable. One study reported that qacA and qacB genes could be found in 0.9% - 83.3% of clinical MRSA isolates worldwide. The goal of this study was to determine the prevalence of chlorhexidine resistance and identify the resistance-associated genes from our MRSA samples using whole genome sequencing (WGS). Methods: 474 MRSA samples were obtained from hospitals in Detroit, MI (287) and Cleveland, OH (187). Whole genome sequencing was performed using the NextSeq (Illumina Inc., CA) platform. The sequencing data was analyzed using ResFinder 4.1, a publicly available database that can be used to identify acquired genes and chromosomal mutations mediating antimicrobial resistance. The output was organized into a data sheet to visualize the presence of the genes of interest. Results: The qacA gene was present in only one MRSA sample from the Cleveland area hospital. In the samples from Detroit, 14 out of 287 showed disinfectant resistance genes. The qacA, qacB, and qacD were present in 1, 6, and 7 samples, respectively. The prevalence of any qac gene in the Cleveland area samples was 0.5%. Meanwhile, the prevalence of any qac gene in Detroit area samples was 4.9%. Among the 7 samples that have qacD gene, 6 samples have more than one copy of qacD. Conclusions: The prevalence of the “qac” gene varied widely based on the origin of the samples. Detroit area samples had more qac genes prevalence than Cleveland area samples. Chlorhexidine is a widely used antiseptic/disinfectant, and it plays a vital role in reducing carriage and preventing infection among hospitalized patients colonized with MRSA. Monitoring and addressing MRSA-reduced susceptibility to chlorhexidine is imperative for maintaining the effectiveness of infection control practices such as decolonization.

Nontraditional Roles of Magnesium Ions in Modulating Sav2152: Insight from a Haloacid Dehalogenase-like Superfamily Phosphatase from Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) infection has rapidly spread through various routes. A genomic analysis of clinical MRSA samples revealed an unknown protein, Sav2152, predicted to be a haloacid dehalogenase (HAD)-like hydrolase, making it a potential candidate for a novel drug target. In this study, we determined the crystal structure of Sav2152, which consists of a C2-type cap domain and a core domain. The core domain contains four motifs involved in phosphatase activity that depend on the presence of Mg2+ ions. Specifically, residues D10, D12, and D233, which closely correspond to key residues in structurally homolog proteins, are responsible for binding to the metal ion and are known to play critical roles in phosphatase activity. Our findings indicate that the Mg2+ ion known to stabilize local regions surrounding it, however, paradoxically, destabilizes the local region. Through mutant screening, we identified D10 and D12 as crucial residues for metal binding and maintaining structural stability via various uncharacterized intra-protein interactions, respectively. Substituting D10 with Ala effectively prevents the interaction with Mg2+ ions. The mutation of D12 disrupts important structural associations mediated by D12, leading to a decrease in the stability of Sav2152 and an enhancement in binding affinity to Mg2+ ions. Additionally, our study revealed that D237 can replace D12 and retain phosphatase activity. In summary, our work uncovers the novel role of metal ions in HAD-like phosphatase activity.

Detection of Novel spa Types in Clinical Isolates of Methicillin-Resistant Staphylococcus aureus in Iraq

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a gram-positive bacterium that is an opportunistic pathogen, causing infections in hospital settings and communities. MRSA has become a significant and increasing problem in Iraq. The aim of this study was to evaluate the genetic mutations of MRSA strains, especially in the spa gene, isolated from patients in Wassit, Iraq.Methods and Results: Biochemical tests were conducted to identify S. aureus isolates and then on MRSA. The MRSA was identified by the Chrome Agar method and confirmed by PCR with genotyping of the mecA gene. The disk diffusion method was used to detect antibiotic resistance to three different common antibiotics used at Wassit hospitals. The Vitek-2 compact system was utilized for the detection of the minimum inhibitory concentration (MIC) of vancomycin. All MRSA strains in this study were tested to screen the mecA gene, with 21 strains subjected to the molecular typing method for the spa gene. Out of 166 samples, 132(79.5%) contained S. aureus and 34(20.4%) were identified as MRSA. Genotyping showed that out of 34 MRSA, 31(91.2%) isolates were mecA-positive. The spa gene was detected in 21(61.8%) isolates out of 34 MRSA samples. The spa typing of 21 MRSA samples revealed four different spa types, as follows: t386 (3/14.3%), t3576 (1/4.8%), t10002 (1/4.8%), and t10234 (1/4.8%). High polymorphism rates were shown in isolates of spa type t386. Conclusion: Our data represent the first report to detect novel mutations in the spa gene in the MRSA clinical isolates from Wassit hospitals, Iraq.

Puerperal mastitis caused by limited community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) clones.

To outline the epidemiology of puerperal mastitis caused by methicillin-resistant Staphylococcus aureus (MRSA) and evaluate the effect of an infection control bundle on its incidence. A surge in MRSA puerperal mastitis was noted in a community hospital in September 2009. MRSA samples from mastitis cases and the environment underwent typing using multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec), gene encoding surface protein A (spa), accessory gene regulator (agr), and pulsed-field gel electrophoresis (PFGE). The phenotypic characteristics, including superantigen toxin profiles, gene encoding Panton-Valentine leucocidin (pvl), and minimal inhibitory concentration (MIC) against vancomycin, were ascertained. Subsequently, an infection control bundle emphasizing contact precautions was introduced, and mastitis incidence rates pre- and post-intervention were compared. The majority of cases occurred within 6 weeks post-delivery in first-time mothers. Of the 42 S. aureus isolates (27 from mastitis and 15 from colonized staff and environmental sources), 25 (92.6%) clinical and 3 (20%) colonized MRSA were identified as ST59-SCCmecVT-spa t437-agr group I with a vancomycin MIC of 1 mg/L, pvl-positive, and predominantly with a consistent toxin profile (seb-selk-selr). PFGE revealed 13 patterns; pulsotype B exhibited clonal relatedness between two clinical and three colonized MRSA samples. Post-intervention, the incidence of both mastitis and MRSA mastitis notably decreased from 13.01 to 1.78 and from 3.70 to 0.99 episodes per 100 deliveries, respectively. Distinct community-associated MRSA (CA-MRSA) clones were detected among puerperal mastitis patients and colonized staff. The outbreak was effectively controlled following the implementation of a targeted infection control bundle.

Prevalence of mecA- and mecC-Associated Methicillin-Resistant Staphylococcus aureus in Clinical Specimens, Punjab, Pakistan.

Methicillin-resistant Staphylococcus aureus (MRSA) is a clinically prevalent bacterium and is resistant to many drugs. Genetic factors such as mec genes are considered to be responsible for this resistance. Recently, Staphylococcal Cassette Chromosome mec (SCCmec) element mutations produced mecC, a new genetic variant that encodes a transpeptidase enzyme (63% similarity with mecA-encoded PBP2a). This cross-sectional study was conducted to establish the prevalence of the mecA and mecC genes among phenotypically identified MRSA and their effectiveness against different antibiotics in clinical specimens. The prevalence of Staphylococcus aureus was 10.2% (n = 102) in the total number of clinical specimens collected (n = 1000). However, the prevalence of MRSA was 6.3% (n = 63) of the total samples collected, while it was 61.8% among total Staphylococcus aureus isolates. mec genes were confirmed in 96.8% (n = 61) isolates of MRSA, while 3.2% (n = 2) were found to be negative for mec genes. The combination of mecA and mecC was detected in 57.1% (n = 36) of the MRSA isolates. The prevalence of lone mecA was 31.8% (n = 20) and that of lone mecC was 7.9% (n = 5) among all the MRSA samples. Penicillin and amoxicillin/clavulanic acid were the most resistant antibiotics followed by norfloxacin (91.2%), levofloxacin (87.1%), ciprofloxacin (83.9%), azithromycin (78.6%), erythromycin (77.4%), moxifloxacin (69.8%), and sulfamethoxazole/trimethoprim (54.9%). On the other hand, vancomycin and teicoplanin (98.4%) were more effective drugs against MRSA followed by linezolid (96.7%), clindamycin (84.6%), chloramphenicol (83.7%), fusidic acid (70.6%), gentamicin (67.7%), and tetracycline (56.8%). In conclusion, a significant prevalence of mecA and mecC has been found among MRSA isolated from clinical specimens, which is likely responsible for antibiotic resistance in MRSA in our clinical settings. However, vancomycin, teicoplanin, and linezolid were found the top three most effective drugs against MRSA in our clinical settings. Thus, MRSA endemics in local areas require routine molecular and epidemiological investigation.

Detection of Some Staphylococcal Enterotoxin Genes in MRSA Strains Using PCR Techniques

In view of the increasing interest in the Methicillin-resistant Staphylococcus aureus (MRSA). The extracted DNA yield was observed using the phenol-chloroform method, it ranged from (1.6-1.8) and concentration ranged from 100 to 800 ng/µl. Five classical enterotoxin genes were investigated in 20 isolates using multiplex PCR method after it had been molecularly identified into methicillin resistant using mec A (which is the key genetic component of methicillin resistance) and fem A genes in a duplex PCR technique. A multiplex PCR test based on the simultaneous amplification of the five genes genes; sea 102bp, seb 164bp, sec 451bp, sed 278 bp and see 209bp was conducted to directly detect the toxin gene content. Our results had showed that most of MRSA samples harbored at least one enterotoxin gene. Multiple toxin gene combinations were also observed. Using this PCR assay we found that among the MRSA strains obtained (n=20). The most commonly found gene was the enterotoxin A sea (n: 18, 90%), which was found alone and together with other toxin genes.

Molecular analysis of Panton-Valentine Leucocidin (pvl) gene among MRSA and MSSA isolates.

The present study was conducted in order to determine the frequency of pvl gene among the pathogenic and healthy population isolates of Methicillin Resistant Staphylococcus aureus (MRSA) and Methicillin Sensitive Staphylococcus aureus (MSSA). For this purpose, nasal swab samples were collected from the healthy individuals (to be used as controls, all the samples were collected irrespective of the sex and age factors), the pathogenic samples were collected from different patients suffering from skin &soft tissue infections caused by S. aureus (to be used as test samples).Both of these population samples were analyzed for the presence of pvl gene. S.aureus were identified through conventional microbiological identification procedures. In the case of normal samples, 70 nasal swabs were collected and only 33 (47%) proved to be S. aureus while 20 pathogenic samples were collected and all (100%) were cleared as S. aureus. For further distribution of samples into MRSA and MSSA, antibiotic susceptibility pattern was checked by using the standard protocols of Kirby-Bauer disc diffusion method. Two antibiotic discs Oxacillin (OX: 1ug) and cefoxitin (FOX: 30ug) were used. Among healthy population, MRSA was found to be 79% (n=26) and MSSA were present as 21% (n= 7). Among pathogenic strains 100% MRSA was detected where n= 20. Detection of pvl gene among the MRSA and MSSA isolates was done by using the uniplex PCR followed by gel electrophoresis. MRSA and MSSA of normal healthy population carried 49% and 7% pvl gene respectively. While, pathogenic MRSA samples carried 46% pvl gene among them. Potentially alarming percentage of pvl gene is present among the normal healthy individuals which indicates a future threat and a major health concern.

Is the Oral Cavity of Intensive Care Unit Pediatric Patients More Susceptible to Methicillin-Resistant Staphylococcus aureus Infection?

Objective: The aim of this study was to assess the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the oral cavity of pediatric patients hospitalized at an intensive care unit (ICU). Methodology: Thirty ICU patients (group 1) and 30 healthy patients (group 2), between 1 and 12 years of age, matched by sex and age, were selected from a public hospital in Brazil. After oral examinations, biological specimens (nostril swab, oral mucosa, and supragingival biofilm) were collected from both groups to verify the presence of Staphylococcus aureus. Identification occurred after growth in Tryptic Soy Broth with 7.5% of NaCl for 48 hours, growth in Mannitol Salt Agar, gram staining, catalase, and coagulase tests. S. aureus isolates were submitted to antibiotic sensitivity test. Results: Only 36.7% of patients in the ICU perform oral hygiene during the hospitalization period and 41.7% presented high level of dental biofilm accumulation. The presence of S. aureus was similar in patients from group 1 (43.3%, 13) and group 2 (50.0%, 15) (p = 0.60). Both groups presented 18 samples each that tested positive for S. aureus. However, when considering patients infected by MRSA, the prevalence was higher in group 1 (eight; 26.7%) than in group 2 (five; 16.7%) but no statistical difference was observed (p = 0.53). In group 1, nine MRSA samples were resistant to erythromycin and seven to clindamycin. In group 2, two MRSA samples were resistant to erythromycin and two to clindamycin. Conclusions: Although ICU children did not show a significant higher carriage of MRSA when compared with the healthy group in the population studied, the number of highly resistant strains in the oral cavity isolated from ICU patients adds an important risk factor to be considered by the medical team as possible source of systemic infections, extended hospital stay, and poor outcomes.

In-Vitro Antimicrobial Drug Susceptibility Pattern of Methicillin Resistant Staphylococcus Aureus (MRSA)

Objective: To determine the in-vitro antimicrobial susceptibility pattern of Methicillin-resistant Staphylococcus aureus (MRSA) isolates using an automated VITEK-2 compact system.
 Study Design: Cross-sectional study.
 Place and Duration of Study: Pakistan Railway Hospital (PRH) Rawalpindi collaborates with the Armed Forces Institute of Pathology (AFIP) Rawalpindi, from Sep 2018 to Aug 2019.
 Methodology: 100 MRSA samples were isolated from tissue, pus, urine, blood, high vaginal swabs (HVS) and ear swabs using standard microbiological techniques. MRSA isolates' antimicrobial susceptibility pattern was made using an automated VITEK-2 compact system.
 Results: Among 100 MRSA isolates, 63% were obtained from pus and 17% from tissue, respectively. MRSA isolates showed 100% sensitivity to Vancomycin, Teicoplanin and Linezolid. Susceptibility to other drugs has shown wide variation, i.e., Tigecycline 97%, Rifampicin 95%, Clindamycin 86%, Tetracycline 79%, and Cotrimoxazole 78%. The minimum inhibitory concentration (MICs) of Vancomycin and Linezolid against MRSA isolates revealed that 41% had 0.5 µg/ml, 46% had one µg/ml, and 13% had two µg/ml for Vancomycin. Whereas for Linezolid, 38 isolates had MIC 1 µg/ml, then 62 isolates had MIC 2 µg/ml.
 Conclusion: All the isolates showed 100% sensitivity to Vancomycin, Teicoplanin and Linezolid. Moreover, being less costly, Clindamycin, Tetracycline and Cotrimoxazole are good oral choices for empirical therapy against minor MRSA infections.

Presence of Antibiotic-Resistant Staphylococcus aureus in Fish and Seafood Originating from Points of Sale in the Tri-City Area (Poland)

Infections by methicillin-resistant Staphylococcus aureus (MRSA) is gradually increasing in the community. There is a potential public health hazard resulting from S. aureus contamination of seafood, which is mainly due to unhygienic handling, processing, and storage environments. In Poland, the limits provided in European Commission Regulation 1441/2007 refer to the presence of Escherichia coli and S. aureus in shelled and shucked products of cooked crustaceans and molluscan shellfish. This study was designed to evaluate the occurrence of MRSA in samples of fish and seafood from commercial outlets located in the Tri-City area (Poland). In this study, we investigated a 44 food samples, including fish and seafood collected from various retail outlets in the Tri-City area of Poland. The first stage of staphylococcus isolation was initial culture in Giolitti-Cantoni broth. After 24 h, if blackening had occurred at the bottom (or there was general blackening of the medium), the samples were spread plated onto a CHROMagar MRSA base. The cultures were then incubated for 24 h at a temperature of 37°C. Of the 44 samples, 26 were positive for MRSA. The samples most often contaminated with MRSA were cephalopods (6 of 9) and crustaceans (10 of 15), followed by samples taken from mollusks (4 of 7) and fish (6 of 13). The correlation between the species from which the samples were obtained and the presence of S. aureus was not significant (P > 0.05). The high frequency of occurrence of MRSA in these products points to the potential risk of transmission of diseases through the food chain. The results obtained are significant and useful for S. aureus risk assessment programs for aquatic products.

Antibacterial apple cider vinegar eradicates methicillin resistant Staphylococcus aureus and resistant Escherichia coli

Methicillin-resistant Staphylococcus aureus (MRSA) and resistant Escherichia coli (rE.coli) infections can spread rapidly. Further they are associated with high morbidity and mortality from treatment failure. Therapy involves multiple rounds of ineffective antibiotics alongside unwanted side effects, alternative treatments are crucial. Apple cider vinegar (ACV) is a natural, vegan product that has been shown to have powerful antimicrobial activity hence we investigated whether ACV could ameliorate these resistant bacteria. The minimum dilution of ACV required for growth inhibition was comparable for both bacteria (1/25 dilution of ACV liquid and ACV tablets at 200 µg/ml were effective against rE. coli and MRSA). Monocyte co-culture with microbes alongside ACV resulted in an increase in monocyte phagocytosis by 21.2% and 33.5% compared to non-ACV treated but MRSA or rE. coli stimulated monocytes, respectively. Label free quantitative proteomic studies of microbial protein extracts demonstrated that ACV penetrated microbial cell membranes and organelles, altering the expression of key proteins. This resulted in significant reductions in total protein expression, moreover we could only detect ribosomal proteins; 50 s 30 s, enolase, phosphenol pyruvate and the ATP synthase subunit in rE. coli. Elongation factor iNOS and phosphoglycerate kinase OS were the only proteins present in MRSA samples following ACV treatment.

Using Whole-Genome Sequencing to Improve Surveillance Measures: Case Study of Methicillin-Resistant Staphylococcus aureus (MRSA) in a Florida Hospital

Background: The CDC considers methicillin-resistant Staphylococcus aureus (MRSA) one of the most important hospital-acquired infections (HAIs) in the United States. However, infection control departments (ICDs) often rely on subjective data to determine whether multiple MRSA cases are a true outbreak and whether the hospital is responsible (community- vs hospital-acquired). Objective: Our objective was to determine whether whole-genome sequencing (WGS) of MRSA provided new insights into on transmission dynamics at large, inner-city hospital in Jacksonville, Florida. Methods: Over a 4-month period, MRSA samples were obtained from 44 infected patients at 3 campuses within a single hospital system. Limited nonpatient identifying information was obtained, including date of collection, campus, unit, reason for admission, and days post admission (DPA) of MRSA diagnosis. Whole-genome sequences were generated using the Illumina platform. Raw reads were processed, and genetic distances were calculated and used to identify genetically linked bacterial infections using FoxSeq version 1.0 software. Results: Based on their length of stay, 10 patients were reported by the ICD as obtaining an HAI. Three distinct “episodes” were evident in which >5 MRSA cases were observed within a 3–5-day period. Genomic analysis identified 5 clusters of linked infections: 4 clusters contained 2 patients and another contained 3. Of these clusters, only 1 contained multiple cases that were reported as HAIs; however, because these case were separated by 2 weeks, it is unlikely that they came from a source in the hospital. The results suggest that HAIs were overreported and that most MRSA present in the hospital likely came from community sources. Conclusions: WGS provided clear evidence that temporally clustered MRSA cases do not imply an outbreak is occurring. Furthermore, ongoing detection of the same community-acquired infections over several months is indicative of a shared source outside of the hospital, which could be uncovered through examination of clinical records. Considering the implications of HAIs, best approaches to combat them should include identifying their sources. As molecular surveillance approaches to infection control are rapidly becoming easier and less expensive, the methods can be used to bring objective clarity to the ICD.Funding: NoneDisclosures: Susanna L. Lamers reports salary from BioInfoExperts and contract research for the NIH, the University of California - San Francisco, and UMASS Medical School.

Colonization of Environmental Methicillin-Resistant Staphylococcus Aureus in a Newly Constructed Children's Outpatient Clinic

<h3>Background</h3> The purpose of this study was to examine prevalence of environmental methicillin-resistant Staphylococcus aureus (MRSA) in a newly constructed children's outpatient clinic. Viable MRSA on floors and select surfaces in waiting areas and two medical units were compared for the last 3 months of construction through the first 6 months of occupation. <h3>Methods</h3> A total of 52 locations were swabbed weekly, including common areas (floors at check-in desks, waiting rooms, and on children's toys), and on patient room floors, counters, and return air ducts in pulmonary and general medicine units (3 rooms tested in each). Testing was performed during the last 3 months of construction (October-December 2018), and the first 6 months after opening (January - June 2019). HardyCHROM MRSA selective and differential agar media was used to identify viable MRSA. <h3>Results</h3> In common areas, during construction we observed 4/80 (5%) positive swabs for MRSA. After occupation, 72 /208 (35%) positive swabs for MRSA were found in the common areas. In pulmonary unit rooms during construction we observed 3/60 (5%) positive samples for MRSA, and 52/234 (22%) positive samples for MRSA after occupation (p < 0.01). In general medicine rooms during construction we observed 10/60 (17%) positive MRSA samples and 75/234 (32%) positive samples for MRSA after occupation (p < 0.01). Significant differences in the presence of viable MRSA between construction and occupation phases were found in the the common area as well (p < 0.01). <h3>Conclusions</h3> This study shows the rapid colonization of the clinical environment with MRSA within the first 6 months of opening of a children's outpatient clinic. The potential link between environmental bacteria and healthcare-associated infections is an important area of research in infectious disease, particularly for outpatient clinics, requiring monitoring studies such as this.

A large-scale investigation and identification of methicillin-resistant Staphylococcus aureus based on peaks binning of matrix-assisted laser desorption ionization-time of flight MS spectra.

Recent studies have demonstrated that the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) could be used to detect superbugs, such as methicillin-resistant Staphylococcus aureus (MRSA). Due to an increasingly clinical need to classify between MRSA and methicillin-sensitive Staphylococcus aureus (MSSA) efficiently and effectively, we were motivated to develop a systematic pipeline based on a large-scale dataset of MS spectra. However, the shifting problem of peaks in MS spectra induced a low effectiveness in the classification between MRSA and MSSA isolates. Unlike previous works emphasizing on specific peaks, this study employs a binning method to cluster MS shifting ions into several representative peaks. A variety of bin sizes were evaluated to coalesce drifted or shifted MS peaks to a well-defined structured data. Then, various machine learning methods were performed to carry out the classification between MRSA and MSSA samples. Totally 4858 MS spectra of unique S. aureus isolates, including 2500 MRSA and 2358 MSSA instances, were collected by Chang Gung Memorial Hospitals, at Linkou and Kaohsiung branches, Taiwan. Based on the evaluation of Pearson correlation coefficients and the strategy of forward feature selection, a total of 200 peaks (with the bin size of 10 Da) were identified as the marker attributes for the construction of predictive models. These selected peaks, such as bins 2410–2419, 2450–2459 and 6590–6599 Da, have indicated remarkable differences between MRSA and MSSA, which were effective in the prediction of MRSA. The independent testing has revealed that the random forest model can provide a promising prediction with the area under the receiver operating characteristic curve (AUC) at 0.8450. When comparing to previous works conducted with hundreds of MS spectra, the proposed scheme demonstrates that incorporating machine learning method with a large-scale dataset of clinical MS spectra may be a feasible means for clinical physicians on the administration of correct antibiotics in shorter turn-around-time, which could reduce mortality, avoid drug resistance and shorten length of stay in hospital in the future.

Differentiation of Community-Associated and Livestock-Associated Methicillin-Resistant Staphylococcus aureus Isolates and Identification of spa Types by Use of PCR and High-Resolution Melt Curve Analysis.

Infections due to methicillin-resistant Staphylococcus aureus (MRSA) are present worldwide and represent a major public health concern. The capability of PCR followed by high-resolution melt (HRM) curve analysis for the detection of community-associated and livestock-associated MRSA strains and the identification of staphylococcal protein A (spa) locus was evaluated in 74 MRSA samples which were isolated from the environment, humans, and pigs on a single piggery. PCR-HRM curve analysis identified four spa types among MRSA samples and differentiated MRSA strains accordingly. A nonsubjective differentiation model was developed according to genetic confidence percentage values produced by tested samples, which did not require visual interpretation of HRM curve results. The test was carried out at different settings, and result data were reanalyzed and confirmed with DNA sequencing. PCR-HRM curve analysis proved to be a robust and reliable test for spa typing and can be used as a tool in epidemiological studies.

Outbreak of Methicillin-resistant Staphylococcus aureus in a Hospital Center for Children's and Women's Health in a Swedish County.

The objective of this study was to investigate a sudden increase in methicillin-resistant Staphylococcus aureus (MRSA) cases primarily in one maternity ward at the Center for Children's and Women's Health at Linköping University Hospital, Sweden. Approximately 300 individuals including patients, their family members, and healthcare workers were screened for MRSA. The antibiotic susceptibility was tested and isolates polymerase chain reaction (PCR)-positive for the mecA gene were spa typed. Isolates with the same antibiogram and spa type were further whole genome sequenced. Compliance to current cleaning and hygiene routines was also controlled, and environmental samples collected. The results showed that a total of 13 individuals were involved in the outbreak. It was caused by a t386 MRSA strain (ST-1, NCBI-accession AB505628) with additional resistance to erythromycin and clindamycin. All cases were epidemiologically connected to the index patient, who had recently emigrated from a high-endemic area for MRSA. With improved cleaning and better compliance to basic hygiene routines, no further cases were reported. This study demonstrates how rapid an MRSA strain can disseminate in a ward with susceptible patients and insufficient cleaning and hygiene. For a better control of MRSA, clinical cultures and screening samples need to be obtained early and more extensively than according to the current recommendations.

Molecular analysis, biofilm formation, and susceptibility of methicillin-resistant Staphylococcus aureus strains causing community- and health care-associated infections in central venous catheters.

The behavior of methicillin-resistant Staphylococcus aureus (MRSA) isolated from central venous catheter-related infection was evaluated to determine its biofilm potential, antimicrobial resistance, and adhesion genes. A total of 1,156 central venous catheters (CVC) were evaluated to screen for pathogens. Antimicrobial sensitivity, biofilm formation potential, and molecular analysis of MRSA were examined following standard guidelines. Of the 1,156 samples, 882 (76%) were colonized by bacteria or candida. Among the infected patients, 69% were male and 36% were female with median age of 32 years. Staphylococcus aureus infected 39% (344/882) of CVCs in patients. Of the 59% (208/344) of patients with MRSA, 57% had community acquired MRSA and 43% had hospital acquired MRSA. Linezolid and vancomycin killed 100% of MRSA; resistance levels to fusidic acid, doxycycline, clindamycin, azithromycin, amikacin, trimethoprim-sulfamethoxazole, gentamycin, tobramycin, and ofloxacin were 21%, 42%, 66%, 68%, 72%, 85%, 95%, 97%, and 98% respectively. Strong biofilm was produced by 23% of samples, moderate by 27%, and weak by 50% of MRSA. The presence of adhesion genes, sdrC and sdrD (90%), eno (87%), fnbA (80%), clfA and sdrE (67%), fnbB, sdrD (61%), and cna (51%), in most MRSA samples suggested that the adhesion genes are associated with biofilm synthesis. The superbug MRSA is a major cause of CVC-related infection. Antibiotic resistance to major classes of antibiotics and biofilm formation potential enhanced superbug MRSA virulence, leading to complicated infection. MRSA causes infection in hospitals, communities, and livestock.

Prevalence and risk factors of MRSA colonisations: a cross-sectional study among personnel in outpatient care settings in Hamburg, Germany

ObjectivesHealthcare workers frequently come into contact with infected individuals and are at a greater risk of infection than the general population due to their occupation. Multidrug-resistant organisms (MDROs) also pose...