Methicillin-resistant Staphylococcus Aureus In Hospitals Research Articles

Genomic characterization and outbreak investigations of methicillin-resistant Staphylococcus aureus in a county-level hospital in China.

Methicillin-resistant Staphylococcus aureus (MRSA) is a common pathogen contributing to healthcare-associated infections, which can result in multiple sites infections. The epidemiological characteristics of MRSA exhibit variability among distinct regions and healthcare facilities. The aim of this study was to investigate the molecular epidemiology and nosocomial outbreak characteristics of MRSA in a county-level hospital in China. A total of 130 non-repetitive MRSA strains were collected from December 2020 to November 2021. Whole-genome sequencing (WGS) was performed to identify antimicrobial resistance and virulence factors. Phylogenetic analysis was conducted to ascertain genetic diversity and phylogenetic relationships. Independent transmission scenarios were determined by the phylogeny derived from single nucleotide polymorphisms (SNPs) within the core genome. All the MRSA isolates were collected from the intensive care unit (30.00%, 39/130), the department of otorhinolaryngology (10.00%, 13/130) and the department of burn unit (9.23%, 12/130). The clinical samples mainly included phlegm (53.85%, 70/130), purulent fluid (24.62%, 32/130), and secretions (8.46%, 11/130). The resistance rates to erythromycin, clindamycin and ciprofloxacin were 75.38, 40.00, and 39.23%, respectively. All the isolates belonged to 11 clonal complexes (CCs), with the major prevalent types were CC5, CC59, and CC398, accounting for 30.00% (39/130), 29.23% (38/130), and 16.92% (22/130), respectively. Twenty sequence types (STs) were identified, and ST59 (25.38%, 33/130) was the dominant lineage, followed by ST5 (23.84%, 31/130) and ST398 (16.92%, 22/130). Three different SCCmec types were investigated, most of isolates were type IV (33.85%, 44/130), followed by type II (27.69%, 36/130) and type III (0.77%, 1/130). The common clonal structures included CC5-ST5-t2460-SCCmec IIa, CC59-ST59-t437-SCCmec IV and CC398-ST398-t034-SCCmec (-), with rates of 16.92% (22/130), 14.62% (19/130), and 13.84% (18/130), respectively. Only 12 panton-valentine leucocidin (PVL) positive strains were identified. Two independent clonal outbreaks were detected, one consisting of 22 PVL-negative strains belongs to CC5-ST5-t2460-SCCmec IIa and the other consisting of 8 PVL-negative strains belongs to CC5-ST5-t311-SCCmec IIa. Overall, our study indicated that the CC5 lineage emerged as the predominant epidemic clone of MRSA, responsible for nosocomial outbreaks and transmission within a county-level hospital in China, highlighting the necessity to strengthen infection control measures for MRSA in such healthcare facilities.

Evaluating the impact of genomic epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) on hospital infection prevention and control decisions.

Genomic epidemiology enhances the ability to detect and refute methicillin-resistant Staphylococcus aureus (MRSA) outbreaks in healthcare settings, but its routine introduction requires further evidence of benefits for patients and resource utilization. We performed a 12 month prospective study at Cambridge University Hospitals NHS Foundation Trust in the UK to capture its impact on hospital infection prevention and control (IPC) decisions. MRSA-positive samples were identified via the hospital microbiology laboratory between November 2018 and November 2019. We included samples from in-patients, clinic out-patients, people reviewed in the Emergency Department and healthcare workers screened by Occupational Health. We sequenced the first MRSA isolate from 823 consecutive individuals, defined their pairwise genetic relatedness, and sought epidemiological links in the hospital and community. Genomic analysis of 823 MRSA isolates identified 72 genetic clusters of two or more isolates containing 339/823 (41 %) of the cases. Epidemiological links were identified between two or more cases for 190 (23 %) individuals in 34/72 clusters. Weekly genomic epidemiology updates were shared with the IPC team, culminating in 49 face-to-face meetings and 21 written communications. Seventeen clusters were identified that were consistent with hospital MRSA transmission, discussion of which led to additional IPC actions in 14 of these. Two outbreaks were also identified where transmission had occurred in the community prior to hospital presentation; these were escalated to relevant IPC teams. We identified 38 instances where two or more in-patients shared a ward location on overlapping dates but carried unrelated MRSA isolates (pseudo-outbreaks); research data led to de-escalation of investigations in six of these. Our findings provide further support for the routine use of genomic epidemiology to enhance and target IPC resources.

Methicillin-Resistant Staphylococcus aureus (MRSA) in a Tertiary Care Hospital in Kuwait: A Molecular and Genetic Analysis.

Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen that causes serious infections in healthcare facilities and in communities. The purpose of this study was to investigate MRSA isolates obtained in a tertiary hospital in Kuwait to assess their antibiotic susceptibility profile and clonal composition. Sixty MRSA isolates collected in 2020 were tested through antibiotic susceptibility testing, spa typing, and DNA microarray analysis. All isolates were found to be susceptible to vancomycin (MIC: ≤3 µg/mL), teicoplanin (MIC: ≤3 µg/mL), rifampicin, and mupirocin, but were resistant to fusidic acid (n = 43, 72%), trimethoprim (n = 27, 45%), ciprofloxacin (n = 31, 51.7%), gentamicin (n = 14; 23.3%), kanamycin (n = 20; 33.3%), chloramphenicol (n = 7; 11.7%), tetracycline (n = 17; 28.3%), erythromycin (n = 19; 31.6%), inducible clindamycin (n = 13; 21.7%), and constitutive clindamycin (n = 2; 3.3%). The isolates belonged to 30 spa types and 13 clonal complexes (CCs). The dominant spa types were t304, t442, t311, t688, and t1234, collectively constituting 28.3% of the isolates. The dominant CCs were CC5 and CC6, which together constituted 46.7% of the isolates. This study provides updated research on antibiotic resistance and changes in the clonal composition of MRSA in a Kuwait hospital, including the disappearance of the ST239-MRSA-III clone that was previously the dominant clone in this hospital.

Evaluation of In-Vitro Activity of Ceftaroline Against Methicillin-Resistant Staphylococcus aureus Clinical Isolates.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major causes of hospital and community-acquired infections. Fewer drugs, such as vancomycin, teicoplanin, and daptomycin, are effective against it, but they come with high toxicity. Fifth-generation cephalosporins like ceftaroline and second-generation cefuroxime are effective against MRSA. Limited studies are available on ceftaroline resistance in the literature. This study was undertaken to determine ceftaroline resistance in MRSA in a tertiary care hospital in Eastern India. A cross-sectional, hospital-based study was carried out with MRSA isolates obtained from various clinical samples of patients. Identification of the isolates to the species level was performed by an automated Vitek system, and selected samples were genotypically confirmed by detecting the mecA gene via real-time PCR. Out of a total of 334 Staphylococcus aureus isolates examined in this study, the prevalence of MRSA was seen in 59.3% (198/334), and methicillin-sensitive Staphylococcus aureus was in 40.7% (136/334). Of the total 198 MRSA isolates, ceftaroline intermediate MRSA was seen in 8.6% (17/198), and ceftaroline sensitive MRSA was in 91.4% (181/198), respectively. Among the 17 ceftaroline intermediate MRSA isolates, 88.2% (15/17) showed aminimum inhibitory concentration (MIC) of 2 µg/ml, and 11.8% (2/17) showed an MIC of 3 µg/ml. All the remaining 91.4% (181/198) isolates were sensitive to ceftaroline and showed an MIC ≤1 µg/ml. Real-time PCR confirmed the presence of the mecA gene in MRSA isolates. In this present study, not a single isolate was resistant to ceftaroline, suggesting that it, being a safer drug, can be used in place of glycopeptides such as vancomycin or teicoplanin and linezolid, where resistance has already been detected. The rational use of ceftaroline could be useful in clinical settings, and further studies will confirm the findings.

Molecular Detection of Hospital-Acquired Methicillin-Resistant Staphylococcusaureus Isolated From Teaching Hospitals in Damascus, Syria

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is an established pathogen responsible for hospital-acquired infections (HAIs). Accurate MRSA diagnosis is of paramount importance to facilitate early and effective treatment and to manage its transmission effectively. The primary objective of our study was to determine the precise prevalence of hospital-acquired MRSA (HA-MRSA) in select teaching hospitals in Damascus by detecting the presence of the mecA gene. Methods: One hundred Staphylococcus aureus isolates were collected from various clinical specimens obtained from inpatients admitted to three major teaching hospitals in Damascus, Syria, including Al-Moussat, Al-Assad, and Tishreen Military Hospitals. These patients met the established criteria for HAIs. The isolates were collected between December 2021 and August 2022. Genus and species confirmation were conducted via polymerase chain reaction (PCR), employing the 16SrDNA gene specific to the Staphylococcus genus and the nuc gene specific to S. aureus. Methicillin resistance was assessed using cefoxitin disc diffusion (CDD) in accordance with Clinical and Laboratory Standards Institute (CLSI) recommendations. The presence of the mecA gene was also detected through PCR. Results: Out of the collected isolates, 67% exhibited resistance to cefoxitin, as determined by the CDD, while 66% were found to be positive for the mecA gene. CDD demonstrated a sensitivity of 100% and a specificity of 97%. Conclusion: This investigation revealed a notably high incidence of HA-MRSA infections within the teaching hospitals under scrutiny. The CDD method displayed significant sensitivity and specificity, making it a dependable alternative to the mecA PCR for MRSA detection. This finding holds substantial importance for the effective implementation of infection control initiatives and strategies aimed at eradicating MRSA and curtailing its spread within our hospital facilities.

The clinical characteristics and molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) among very elderly people in Japan.

Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial infection-causing pathogen. The clonal shift from staphylococcal cassette chromosome mec (SCCmec) type II MRSA to SCCmec type IV MRSA has occurred rapidly in acute-care hospitals. However, the epidemiology and clinical impacts of MRSA in geriatric hospitals are poorly documented. We performed a molecular epidemiological analysis of the clinical isolates and retrospectively investigated the clinical characteristics of SCCmec type IV MRSA in elderly individuals. MRSA isolates were grouped according to the SCCmec type and virulence genes (tst, sea, seb, sec, and lukS/F-PV), and multi-locus sequence typing (MLST) was performed. Of the 145 MRSA isolates obtained from patients with a median age of 85 years, 100 (69.0%) were obtained from sputum samples, 22 (15.2%) from skin and soft tissues, and seven (4.8%) from blood samples. The most prevalent clone was SCCmec type IV/clonal complex (CC)1/sea+ (59.3%), followed by SCCmec type I/sequence type (ST) 8 (17.3%). Of the 17 (11.7%) strains to which an anti-MRSA drug was administered by a physician, only three were SCCmec type IV/CC1/sea+ (17.6%) and five were SCCmec type I/ST8 (29.4%). SCCmec type IV/CC1/sea+ MRSA was more frequently isolated in long-term care wards than were SCCmec type I/ST8 strains (odds ratio: 2.85, 95% confidence interval: 1.08-7.54) and was less frequently treated as the cause of MRSA infections (odds ratio: 0.15, 95% confidence interval: 0.03-0.73). SCCmec type IV/CC1/sea+ MRSA was the predominant clone and could be easily transmissible and be capable of colonization. Geriatr Gerontol Int 2023; 23: 744-749.

Whole-Genome Sequencing-Based Screening of MRSA in Patients and Healthcare Workers in Public Hospitals in Benin.

Methicillin-resistant Staphylococcus aureus (MRSA) constitutes a serious public health concern, with a considerable impact on patients' health, and substantial healthcare costs. In this study, patients and healthcare workers (HCWs) from six public hospitals in Benin were screened for MRSA. Strains were identified as MRSA using conventional microbiological methods in Benin, and confirmed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in Belgium. Whole-genome sequencing (WGS) was used on the confirmed MRSA isolates, to characterize their genomic content and study their relatedness. Amongst the 305 isolates (304 wound swabs and 61 nasal swabs) that were collected from patients and HCWs, we detected 32 and 15 cases of MRSA, respectively. From this collection, 27 high-quality WGS datasets were obtained, which carried numerous genes and mutations associated with antimicrobial resistance. The mecA gene was detected in all the sequenced isolates. These isolates were assigned to five sequence types (STs), with ST8 (55.56%, n = 15/27), ST152 (18.52%, n = 5/27), and ST121 (18.52%, n = 5/27) being the most common. These 27 isolates carried multiple virulence genes, including the genes encoding the Panton-Valentine leukocidin toxin (48.15%, n = 13/27), and the tst gene (29.63%, n = 8/27), associated with toxic shock syndrome. This study highlights the need to implement a multimodal strategy for reducing the risk of the cross-transmission of MRSA in hospitals.

Prevalence, antimicrobial susceptibility pattern and multidrug resistance of methicillin-resistant Staphylococcus aureus isolated from clinical samples at a tertiary care teaching hospital: an observational, cross-sectional study from the Himalayan country, Nepal

ObjectiveWe sought to determine the prevalence and antimicrobial susceptibility pattern of methicillin-resistant Staphylococcus aureus (MRSA) isolated from the clinical samples at a tertiary care hospital in Nepal.MethodsCross-sectional, observational study design.Study...

Prevalence of mecA and Panton-Valentine Leukocidin Genes in Staphylococcus aureus Clinical Isolates from Gaza Strip Hospitals.

Methicillin-resistant Staphylococcus aureus (MRSA) are spreading worldwide in hospital and community settings, thus posing a serious public health problem. Panton-Valentine Leukocidin (PVL), an important virulence factor of S. aureus, is a marker of community-acquired MRSA. Here we determined the prevalence of pvl genes among S. aureus isolates from different hospitals in the Gaza Strip, Palestine. A total of 285 S. aureus isolates were collected from five different hospitals in the Gaza Strip. All isolates were characterized for their susceptibility patterns to available antimicrobial agents and by using multiplex PCR for the detection of mecA and pvl genes. The overall prevalence of MRSA in Gaza hospitals was 70.2% (range: 76.3% to 65.5%) and that of pvl among S. aureus isolates was 29.8% (range: 32.9% to 26.2%). The pvl gene was equally prevalent among MRSA isolates (30.5%) and MSSA isolates (28.2%). The most effective antibiotics were rifampicin, vancomycin, and clindamycin, with susceptibility rates of 91.2%, 88.7%, and 84.6%, respectively. The highest percentage of strains were observed to be resistant to penicillin and amoxicillin with clavulanic acid-96.1% and 73.6%, respectively. Our results showed a high prevalence of MRSA and pvl-positive isolates in Gaza Strip hospitals, which likely reflects the situation in the community. It is mandatory to implement systematic surveillance of both hospital and community isolates, together with interventions (such as increased hand hygiene, use of hydroalcoholic solutions, and isolation of carriers) to limit their spread.

Multidrug-Resistant Staphylococcus aureus Isolates in a Tertiary Care Hospital, Kingdom of Bahrain.

Methicillin-resistant Staphylococcus aureus (MRSA) is a ubiquitous pathogen associated with a wide spectrum of human infections. In recent decades, MRSA infections have been increasingly reported in individuals without established risk factors, infecting immunocompetent members of the community. This emergence is attributed to the production of various virulence factors, notably Panton-Valentine leukocidin(PVL). The aim of this study was to better understand the prevalence, antibiotic resistance profiles, and molecular characteristics of S. aureus and MRSA in a tertiary care hospital in the Kingdom of Bahrain. This cross-sectional study was carried out in a tertiary hospital for a one-year period, from December 2020 to December 2021. A total of 161 consecutive S. aureus isolates were collected. Antibiotic susceptibility was tested using BD Phoenix™ automated identification and susceptibility testing system. Molecular analysis was conducted via conventional PCR and conventional multiplex PCR for SCCmec typing. In this study, 161 S. aureus isolates were investigated, 60% (n=97) were characterized as MRSA, of which, 12% (n=12) were healthcare-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) while 88% (n=85) were community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA). No statistically significant difference (P>0.05) in antibiotic resistance trends between HA-MRSA and CA-MRSA was detected. Multidrug resistance (MDR) amounted to 19% (n=30) of all S. aureus isolates, 14% (n=9) of methicillin-susceptible Staphylococcus aureus (MSSA) isolates, and 22% (n=21) of MRSA isolates. SCCmec typing demonstrated a high prevalence of type IV (61%, n=59), followed by type V (32%, n=31), then type II (4%, n=4), and type III (3%, n=3). The PVL prevalence was 39% (n=25) in MSSA and 62% (n=60) in MRSA, 33% (n=4) in HA-MRSA, and 66% (n=56) in CA-MRSA. This study demonstrated the emergence of PVL-producing CA-MRSA in a tertiary care hospital, as well as the detection of PVL-producing MDR strains. This development prompts serious measures to be taken in order to sustain a healthy clinical environment.

Reduction in the prevalence of methicillin-resistant Staphylococcus aureus in tissue and wound swab samples taken from outpatients attending a specialist diabetic foot clinic 2005-2021.

To assess annual change in prevalence of methicillin resistant Staphylococcus aureus (MRSA) from tissue and wound swab samples from foot ulcers (DFUs) in people with diabetes between 2005 and 2021. A retrospective analysis of everyone with MRSA positive wound or tissue swabs taken from our specialist multidisciplinary foot clinic between July 2005 and July 2021. A total of 406 MRSA positive isolates from DFU swabs were identified from 185 individuals attending the foot clinic. There were 22 hospital-acquired infections (HAIs) and 159 community-acquired infections (CAIs). Fifty-two per cent (n= 37) of these individuals from 2010 to 2021 (n= 71) had presence of at least three risk factors for MRSA. The total number of swabs sent was 6312 from 1916 individuals living with diabetes. Annual MRSA DFU prevalence peaked in 2008 at 14.6% (n= 38), decreased in 2013 to 5.2% (n= 20) and did not exceed 4% (n= 6) from 2015 to 2021. Hospital MRSA was lowest in 2021 (n= 211), a 76% fall from 2007 (n= 880). Incidence of MRSA HAI from 2015 to 2021 ranged from 5.4% (n= 14) in 2020 to 11.5% (n= 41) in 2018. Prevalence of MRSA in DFU infections treated as outpatients is decreasing in line with falls in hospital acquired blood-borne infections and with overall hospital MRSA incidence. This is likely a reflection of the combination of interventions, including stringent antibiotic prescribing and decolonisation strategies. Reduction in prevalence should have positive impact on outcomes in people living with diabetes, reducing the complication of osteomyelitis and necessity for long-term antibiotic administration.

Identification of Risk Factors for Nasal Colonization of Methicillin-resistant Staphylococcus aureus and Vancomycin-resistant Staphylococcus aureus in Health Workers at a Tertiary Hospital, Indonesia

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) and Vancomycin-resistant S. aureus (VRSA) frequently cause nosocomial infections yearly. During the COVID-19 pandemic, the potential for excessive use of antibiotics is a global threat to the increasing incidence of multiresistant bacteria. AIM: This study aimed to determine MRSA and VRSA colonization and identify factors associated with the risk of MRSA and VRSA nasal colonization in health workers at Dr. Soemarno Sosroatmodjo General Hospital, Kuala Kapuas, as one of the type C hospitals in Indonesia. METHODS: This cross-sectional analytic study at Dr. Soemarno Sosroatmodjo General Hospital, a tertiary hospital in Indonesia. A 128 health workers’ subjects had undergone nasal swab screening for MRSA and VRSA colonization examinations. Then, they were asked to complete a questionnaire concerning the risk factors of MRSA and VRSA infections. RESULTS: Nasal swab results obtained as many as 30 (23.5%) MRSA positive subjects and 6 (4.7%) subjects with positive VRSA. The most common risk factors that led to MRSA colonization included a history of positive MRSA in the previous hospital (60%), a history of ear, nose, and throat infection (41.7%), and did not do hand rub/handwash (36.7%). In comparison, the most risk factors for VRSA colonization were having pigs farm at home (33.3%), a history of positive MRSA in the previous hospital (20%), and a history of hospitalization in the past 6–12 months (16.7%). The results of multivariate analysis showed the most powerful and statistically significant risk factors in influencing nasal MRSA colonization were a history of positive MRSA in the previous hospital (OR 13.69, 95% confidence intervals [CI]: 1.34–140.25, p = 0.028) and did not do hand rub/handwash (OR 2.95, 95% CI: 1.167–7.49, p = 0.023). Meanwhile, marital status (OR 0.160, 95% CI: 0.02–1.06), p = 0.058) and home care service (OR 6.10, 95% CI: 0.79–46.96, p = 0.082) were the strongest risk factors for nasal colonization of VRSA but not statistically significant. CONCLUSION: As many as, 23.5% and 4.7% of healthcare workers’ subjects were found with nasal colonization of MRSA and VRSA, respectively. Accordingly, strict policies are needed to minimize the transmission of these organisms from the hospital setting to the community.

Considering the precautionary principle and its application to MRSA and SARS-CoV-2 as emerging novel pathogens of their time.

In the 1980s Contact Precautions were introduced as a precautionary measure to control the emerging threat of antimicrobial resistance in hospitals, particularly methicillin resistant Staphylococcus aureus (MRSA). Today, antimicrobial resistance remains a concerning global public health threat, and a focus for hospital patient safety priorities. In late 2019 a novel respiratory virus described as SARS-CoV-2, was reported. Just as MRSA had prompted control measures developed in the context of limited information and understanding of the pathogen, public health control measures against SARS-CoV-2 were promptly and strictly implemented. Whilst SARS-CoV-2 control measures were successful at containing the virus, numerous detrimental socio-economic and health impacts have led to a rebalancing of harms versus benefits and loosening of restrictions. Conversely, evidence collated over the past 50 years, suggests that Contact Precautions are not superior to well-applied standard infection prevention and control precautions in controlling MRSA acquisition in hospitals. Several harms associated with Contact Precautions, affecting patient safety, financial costs, and organisational culture, are described. However, rebalancing of hospital MRSA control policies has been slow to materialise. This commentary invites infection prevention and control policy makers to reflect and revise policies for the control of MRSA in hospitals so that harms do not outweigh benefits.

High Prevalence of Multi-drug Resistant Methicillin-Resistant Staphylococcus aureus in Tertiary Egyptian Hospitals.

Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging cause of morbidity and mortality worldwide. This work aimed to study the occurrence of multidrug-resistant MRSA (MDR-MRSA) in tertiary Egyptian hospitals and determine the antimicrobial susceptibilities and the genetic relatedness of isolates for epidemiological assessment. A total of 170 S. aureus isolates were collected from two Egyptian tertiary hospitals in Cairo, between September 2017 and December 2018. MRSA isolates were identified using the conventional microbiological methods and confirmed by the PCR assays targeting nuc gene, a surrogate marker of S. aureus and the mecA gene for genotypic identification of methicillin resistance. Antimicrobial susceptibility was determined using the Kirby-Bauer disk diffusion method and the isolates were grouped into different antibiotypes based on their antibiograms. The genetic relatedness among MDR-MRSA isolates was determined by ERIC-PCR-based molecular typing. High prevalence of MRSA isolates was identified (138/170, 81.2%) with 79% of isolates (109/138, 79%) being MDR-MRSA. MRSA isolates were resistant to diverse classes of antimicrobials including β-lactams, aminoglycosides and macrolides. Among MRSA isolates, the highest resistance rate was to each cefoxitin and penicillin (100%) and the highest susceptibility was to linezolid (92%). Based on the antibiograms of 109 MDR-MRSA isolates, 52 antibiotypes were determined, and 46 different ERIC fingerprints were identified among MDR-MRSA antibiotypes. MRSA infections remain a noteworthy problem in Egyptian hospitals. MDR-MRSA isolates showed significant genetic diversity indicating the alarmingly high prevalence. Studies should be performed frequently, even in each healthcare setting, to determine the epidemiology of MRSA isolates and their antimicrobial susceptibility profiles for effective control measures of MRSA infections and better healthcare management.

A facile and general method for synthesis of antibiotic-free protein-based hydrogel: Wound dressing for the eradication of drug-resistant bacteria and biofilms.

Antibacterial protein hydrogels are receiving increasing attention in the aspect of bacteria-infected-wound healing. However, bacterial drug resistance and biofilm infections lead to hard healing of wounds, thus the construction of biological agents that can overcome these issues is essential. Here, a simple and universal method to construct antibiotic-free protein hydrogel with excellent biocompatibility and superior antibacterial activity against drug-resistant bacteria and biofilms was developed. The green industrial microbicide tetrakis (hydroxymethyl) phosphonium sulfate (THPS) as cross-linking agent can be quickly cross-linked with model protein bovine serum albumin (BSA) to form antibacterial hydrogel through simple mixing without any other initiators, subsequently promoting drug-resistance bacteria-infected wound healing. This simple gelatinization strategy allows at least ten different proteins to form hydrogels (e.g. BSA, human serum albumin (HSA), egg albumin, chymotrypsin, trypsin, lysozyme, transferrin, myohemoglobin, hemoglobin, and phycocyanin) under the same conditions, showing prominent universality. Furthermore, drug-resistance bacteria and biofilm could be efficiently destroyed by the representative BSA hydrogel (B-Hydrogel) with antibacterial activity, overcoming biofilm-induced bacterial resistance. The in vivo study demonstrated that the B-Hydrogel as wound dressing can promote reepithelization to accelerate the healing of methicillin-resistant staphylococcus aureus (MRSA)-infected skin wounds without inducing significant side-effect. This readily accessible antibiotic-free protein-based hydrogel not only opens an avenue to provide a facile, feasible and general gelation strategy, but also exhibits promising application in hospital and community MRSA disinfection and treatment.

A Review of Prevalence, Antimicrobial Susceptibility Patterns and Molecular Characteristics of Methicillin-Resistant <i>Staphylococcus aureus</i> (MRSA) in the Caribbean

Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen causing infections resulting in severe morbidity and mortality worldwide. To date, the true nature and extent of MRSA infections in the Caribbean are not well understood. This is a review of the limited studies in the Caribbean describing the prevalence, epidemiology, and molecular characteristics of MRSA in hospitalized and non-hospitalized patients. Relevant articles were searched and extracted from PubMed and Mendeley and a narrative review of the findings was constructed. An aggregate of 24 articles, from 1999 to 2020, was found from 10 of 27 countries. Majority of the studies were from Trinidad and Tobago (29%) and Jamaica (21%) while 50% were from Barbados, Dominican Republic, Martinique, Haiti, Cuba, St. Kits & Nevis, Guadeloupe, and Guyana. Approximately 75% of investigations were conducted on hospitalized patients versus 20% on outpatients. The data revealed geographical differences in the prevalence of MRSA within the Caribbean; 20% - 100% of Staphylococcus aureus clinical isolates from hospitalized patients and outpatients were resistant to methicillin, macrolides, and fluoroquinolones, but susceptible to several non-beta lactam antibiotics, due to the widespread occurrence of CA-MRSA clone ST8 SCCmec IV, PVL positive. There was moderate prevalence of ST72 SCCmec V (14% - 25%) in both hospital and community settings in a few of the countries while ST30 SCCmec IV, PVL positive, was moderately prevalent (27%) only in Dominican Republic. Also, there was moderate prevalence of HA-MRSA ST5 SCCmec II (18%) in community settings in the Dominican Republic and Martinique, but high prevalence of HA-MRSA ST239 SCCmec III (60%) in hospitalized patients in Cuba and Trinidad & Tobago. The epidemiologic profile of MRSA in both hospital and community settings is changing in the Caribbean. Epidemiological studies on outpatient settings and the implementation of stringent hospital infection control measures are needed in the region.

173. Deciphering COVID-19-Associated Effects on Hospital MRSA Transmission and Social Networks

173. Deciphering COVID-19-Associated Effects on Hospital MRSA Transmission and Social Networks

Computational Design and Lab-Based Investigation of a Novel Small-Molecule Inhibitor That Targets CadA Metal Efflux Pump Activity in Hospital Methicillin-Resistant Staphylococcus Aureus: A Research Protocol

Introduction: Heavy metal exposure has been previously reported to decrease bacterial growth. During the growing antibiotic crisis in healthcare settings, metals may reduce bacterial burden in hospital environments. Despite proving successful, this has driven the evolution of metal-resistant strains like methicillin-resistant Staphylococcus aureus (MRSA). By expelling cadmium and zinc through surface efflux pumps such as CadA, MRSA is able to thrive in metal-rich environments. This protocol investigates the inhibitory activity of Scinapsin, a novel small-molecule inhibitor designed to bind the catalytic site of CadA. Scinapsin could be applied to clinical settings to combat metal resistance in MRSA populations amidst the COVID-19 pandemic. Methods: Computational biochemistry is used to characterize the structure of the S. aureus CadA protein. Small-molecule library screening generated a hit compound, which after modification to improve binding affinity produced the final Scinapsin structure. Several MSRA strains were screened for the presence of CadA from which the most favourable strain for the experiment is chosen (i.e. prevalence in hospitals, CadA expression levels). For the experimental protocol, MRSA strains with metal resistance are incubated with increasing concentrations of Scinapsin, either in the presence or absence of zinc and cadmium (at 50% of predetermined MIC). Samples are then diluted and plated to allow for CFU counting. Results: Scinapsin is anticipated to have an inhibitory effect on MRSA growth in the presence of metals at 50% MIC, confirming the successful inactivation of CadA function. A saturation point may also occur at higher concentrations of Scinapsin where no further growth inhibition is achieved. Discussion: Docking analysis has confirmed the theoretical feasibility for Scinapsin to act as a CadA-specific inhibitor. In an in vitro setting like the one presented, Scinapsin should allow for excess zinc and cadmium to accumulate in the cytoplasm and ultimately cause cell death. Further experiments could aim to confirm the proposed biological mechanism of antibacterial activity. Conclusion: Scinapsin holds promise in reversing metal resistance in hospital MRSA populations and may pave the way for other small-molecule antibacterial drugs. Future research is needed to determine safe levels of Scinapsin exposure for humans and how this inhibitor affects other hospital microbes.

A random forest model based on core genome allelic profiles of MRSA for penicillin plus potassium clavulanate susceptibility prediction.

Treatment failure of methicillin-resistant Staphylococcus aureus (MRSA) infections remains problematic in clinical practice because therapeutic options are limited. Penicillin plus potassium clavulanate combination (PENC) was shown to have potential for treating some MRSA infections. We investigated the susceptibility of MRSA isolates and constructed a drug susceptibility prediction model for the phenotype of the PENC. We determined the minimum inhibitory concentration of PENC for MRSA (n=284) in a teaching hospital (SRRSH-MRSA). PENC susceptibility genotypes were analysed using a published genotyping scheme based on the mecA sequence. mecA expression in MRSA isolates was analysed by qPCR. We established a random forest model for predicting PENC-susceptible phenotypes using core genome allelic profiles from cgMLST analysis. We identified S2-R isolates with susceptible mecA genotypes but PENC-resistant phenotypes; these isolates expressed mecA at higher levels than did S2 MRSA (2.61 vs 0.98, P<0.05), indicating the limitation of using a single factor for predicting drug susceptibility. Using the data of selected UK-sourced MRSA (n=74) and MRSA collected in a previous national survey (NA-MRSA, n=471) as a training set, we built a model with accuracies of 0.94 and 0.93 for SRRSH-MRSA and UK-sourced MRSA (n=287, NAM-MRSA) validation sets. The AUROC of this model for SRRSH-MRSA and NAM-MRSA was 0.96 and 0.97. Although the source of the training set data affects the scope of application of the prediction model, our data demonstrated the power of the machine learning approach in predicting susceptibility from cgMLST results.

Prevalence of MecC Gene Among Methicillin Resistant Staphylococcus aureus isolated from Patients in Ain-Shams University Hospital

Methicillin-Resistant Staphylococcus aureus (MRSA) is an important cause of healthcare associated infections globally. New mecA homologue (mecC), was first reported in the UK and Denmark. The mecC mediated MRSA is resistant only to Β-lactams antibiotics and is sensitive to other antibiotics. Detecting the prevalence of mecC MRSA provides more options in treatment of MRSA infections. The aim of this study was to prevalence of mecC gene in clinical isolates of MRSA in Ain-Shams university hospitals &amp; to correlate Minimal Inhibitory concentration (MIC) of Oxacillin with the mecC gene expression in MRSA isolates. Fifty MRSA isolates were collected from different intensive care units (ICUs) of Ain-Shams university hospital from April-December 2018. Methicillin resistance was detected by Cefoxitin disc, and antimicrobial susceptibility testing was done for all isolates and its results were interpreted according to Clinical &amp; Laboratory Standards Institute (CLSI) guidelines 2018. Minimal Inhibitory Concentration of Oxacillin was detected using Oxacillin E-test and the results were interpreted according to the manufacturer’s instructions, then Polymerase Chain Reaction was done to detect mecA and mecC genes among MRSA isolates. Fifty isolates were identified as MRSA by Cefoxitin disc out of 163 samples. Twelve isolates were sensitive to Oxacillin while 38 isolates were resistant to Oxacillin. All isolates were positive to mecA gene while only 3 isolates were positive to both mecA and mecC genes. MecC is a new emerging gene responsible for methicillin resistance in staphylococci and was detected in 6 % of the isolates in this study.