Multidrug-resistant Methicillin-resistant Staphylococcus Aureus Research Articles

Treatment of MRSA Infection: Where are We?

Staphylococcus aureus is a leading cause of septicemia, endocarditis, pneumonia, skin and soft tissue infections, bone and joint infections, and hospital-acquired infections. In particular, methicillin-resistant Staphylococcus aureus (MRSA) is associated with high morbidity and mortality, and continues to be a major public health problem. The emergence of multidrug-resistant MRSA strains along with the wide consumption of antibiotics has made anti-MRSA treatment a huge challenge. Novel treatment strategies (e.g., novel antimicrobials and new administrations) against MRSA are urgently needed. In the past decade, pharmaceutical companies have invested more in the research and development (R&D) of new antimicrobials and strategies, spurred by favorable policies. All research articles were collected from authentic online databases, including Google Scholar, PubMed, Scopus, and Web of Science, by using different combinations of keywords, including 'anti-MRSA', 'antibiotic', 'antimicrobial', 'clinical trial', 'clinical phase', clinical studies', and 'pipeline'. The information extracted from articles was compared to information provided on the drug manufacturer's website and Clinical Trials.gov (https://clinicaltrials.gov/) to confirm the latest development phase of anti-MRSA agents. The present review focuses on the current development status of new anti-MRSA strategies concerning chemistry, pharmacological target(s), indications, route of administration, efficacy and safety, pharmacokinetics, and pharmacodynamics, and aims to discuss the challenges and opportunities in developing drugs for anti-MRSA infections.

Cinnamaldehyde targets SarA to enhance β-lactam antibiotic activity against methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) is a current global public health problem due to its increasing resistance to the most recent antibiotic therapies. One critical approach is to develop ways to revitalize existing antibiotics. Here, we show that the phytogenic compound cinnamaldehyde (CIN) and β-lactam antibiotic combinations can functionally synergize and resensitize clinical MRSA isolates to β-lactam therapy and inhibit MRSA biofilm formation. Mechanistic studies indicated that the CIN potentiation effect on β-lactams was primarily the result of inhibition of the mecA expression by targeting the staphylococcal accessory regulator sarA. CIN alone or in combination with β-lactams decreased sarA gene expression and increased SarA protein phosphorylation that impaired SarA binding to the mecA promoter element and downregulated virulence genes such as those encoding biofilm, α-hemolysin, and adhesin. Perturbation of SarA-mecA binding thus interfered with PBP2a biosynthesis and this decreased MRSA resistance to β-lactams. Furthermore, CIN fully restored the anti-MRSA activities of β-lactam antibiotics in vivo in murine models of bacteremia and biofilm infections. Together, our results indicated that CIN acts as a β-lactam adjuvant and can be applied as an alternative therapy to combat multidrug-resistant MRSA infections.

Evaluation of the in vitro and in vivo antimicrobial activity of alkaloids prepared from Chelidonium majus L. using MRSA- infected C. elegans as a model host

Chelidonium majus L. contained alkaloids as its main component, exhibiting various biological activities, particularly antibacterial activity. This study aimed to extract alkaloids from C. majus L. (total alkaloids) and evaluate their antibacterial activity both in vitro and in vivo. Reflux extraction was carried out on C. majus L., and the extract was purified with HPD-600 macroporous resin and 732 cation exchange resin columns. Infection modeling of Caenorhabditis elegans (C. elegans) was established to investigate the impact of Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-sensitive Staphylococcus aureus (MSSA) on the motility, longevity, and reactive oxygen species (ROS) levels of wild-type worms (N2 strain). The effects of total alkaloids on longevity and ROS were further evaluated in infected N2 worms. Additionally, the effect of total alkaloids on the stress resistance of C. elegans and the mechanism of action were investigated. By utilizing CB1370, DR26 and CF1038 transgenic strains of C. elegans to identify whether the antibacterial activity of total alkaloids was dependent on DAF-2/DAF-16 pathway. The results showed that total alkaloids exhibited a significant antibacterial activity against both MRSA and MSSA (MIC 31.25 μg/mL). Compared with MSSA, the MRSA exhibited a stronger inhibitory effect on the movement behavior and development of worms, along with faster pathogenicity and unique virulence factors. Total alkaloids also displayed the ability to extend the lifespan of C. elegans under oxidative stress and heat stress, and reduce the expression of ROS. The antibacterial activity of total alkaloids was primarily dependent on the DAF-2/DAF-16 pathway, and the presence of functional DAF-2 was deemed essential in total alkaloids mediated immune response against MRSA. Moreover, the antibacterial and anti-infection effects of total alkaloids were found to be associated with the daf-16 gene fragment.

Emergence and clonal expansion of a qacA-harbouring sequence type 45 lineage of methicillin-resistant Staphylococcus aureus

The past decade has seen an increase in the prevalence of sequence type (ST) 45 methicillin-resistant Staphylococcus aureus (MRSA), yet the underlying drivers for its emergence and spread remain unclear. To better understand the worldwide dissemination of ST45 S. aureus, we performed phylogenetic analyses of Australian isolates, supplemented with a global population of ST45 S. aureus genomes. Our analyses revealed a distinct lineage of multidrug-resistant ST45 MRSA harbouring qacA, predominantly found in Australia and Singapore. Bayesian inference predicted that the acquisition of qacA occurred in the late 1990s. qacA was integrated into a structurally variable region of the chromosome containing Tn552 (carrying blaZ) and Tn4001 (carrying aac(6’)-aph(2”)) transposable elements. Using mutagenesis and in vitro assays, we provide phenotypic evidence that qacA confers tolerance to chlorhexidine. These findings collectively suggest both antimicrobial resistance and the carriage of qacA may play a role in the successful establishment of ST45 MRSA.

Occurrence of Methicillin-Resistant Staphylococcus aureus (MRSA) in Bovine Bulk Milk and Farm Workers in Smallholder Dairy Farming Systems in Northwestern Ethiopia.

Staphylococcus aureus is a common pathogen responsible for causing various human and animal infections and is well known for its ability to develop resistance to multiple antibiotics. This study aimed to evaluate the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) in bulk milk and dairy farms in northwestern Ethiopia and to determine their phenotypic and genotypic antimicrobial susceptibility patterns. We collected 50 bulk milk samples from 50 dairy farms and 50 hand swabs from dairy milkers. The cefoxitin disk diffusion test and PCR-based assays were used to identify MRSA isolates. In addition, cefoxitin-resistant isolates were tested for susceptibility to other antibiotics using the Kirby-Bauer disk diffusion method. The results showed that MRSA was detected in 8 samples: 6 from bulk milk samples (12%) and 2 from hand swabs (4%). All MRSA isolates exhibited a high resistance rate to penicillin (100%), followed by tetracycline (75%), ciprofloxacin (25%), chloramphenicol (25%), erythromycin (25%), gentamycin (12.5%), and trimethoprim-sulfamethoxazole (12.5%). Moreover, 72% of the isolates showed resistance to three or more antibiotic classes and were classified as multidrug-resistant. This study identified methicillin-resistant Staphylococcus aureus and multidrug-resistant MRSA in bulk milk and dairy farms in northwestern Ethiopia. These findings highlight the potential risk of transmission of these antibiotic-resistant bacteria to humans and the need for improved antibiotic stewardship in the dairy sector using the One Health approach.

Isolation and encapsulation of bacteriophage with chitosan nanoparticles for biocontrol of multidrug-resistant methicillin-resistant Staphylococcus aureus isolated from broiler poultry farms

This study was divided into two parts. The first part, the determination of methicillin-resistant Staphylococcus aureus (MRSA) prevalence in 25 broiler chicken farms, with the detection of multidrug resistant MRSA strains. The prevalence of MRSA was 31.8% (159 out of 500 samples) at the level of birds and it was 27% (27 out of 100) in the environmental samples. The highest antimicrobial resistance of the recovered MRSA strains was recorded to streptomycin (96%). All isolates (100%) had multidrug resistance (MDR) to four or more antibiotics with 16 distinct antibiotic resistant patterns, and multiple antibiotic resistance index (MARI) of 0.4–1. The second part, implementing novel biocontrol method for the isolated multidrug resistant MRSA strains through the isolation of its specific phage and detection of its survival rate at different pH and temperature degrees and lytic activity with and without encapsulation by chitosan nanoparticles (CS-NPs). Encapsulated and non-encapsulated MRSA phages were characterized using transmission electron microscope (TEM). Encapsulation of MRSA phage with CS-NPs increasing its lytic activity and its resistance to adverse conditions from pH and temperature. The findings of this study suggested that CS-NPs act as a protective barrier for MRSA phage for the control of multidrug resistant MRSA in broiler chicken farms.

A Comparative Phenotypic and Genomic Analysis of Methicillin-Resistant Staphylococcus aureus ST45 Isolates From Cellulitis and Osteomyelitis in Taiwan.

Methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST) 45 is a globally disseminated MRSA lineage. Herein, we investigated whether MRSA ST45 isolates from cellulitis and from osteomyelitis display distinctive phenotypic and genomic characteristics. A total of 15 MRSA ST45 isolates from cellulitis (CL-MRSA; n = 6) or osteomyelitis (OM-MRSA; n = 9) were collected in a Taiwan hospital. These MRSA ST45 isolates were characterized for their antimicrobial susceptibility, biofilm-forming ability, cellular infectivity in vitro, and pathogenicity in vivo. Four CL-MRSA and 6 OM-MRSA ST45 isolates were selected for whole-genome sequencing (WGS). Antibiotic resistance tests showed that all OM-MRSA ST45 strains, but not CL-MRSA ST45 strains, were resistant to ciprofloxacin, levofloxacin, gentamicin, and doxycycline. Compared to the CL-MRSA ST45 isolates, the OM-MRSA ST45 isolates had stronger biofilm-forming ability and cellular infectivity and caused more severe disease in mice. WGS analysis revealed that these OM-MRSA ST45 isolates carry multiple common mutations or polymorphisms in genes associated with antibiotic resistance and virulence. Moreover, the transposable elements IS256 and IS257R2 were found only in the OM-MRSA ST45 isolates. The emergence and spread of the highly pathogenic and multidrug-resistant ST45 MRSAs identified from osteomyelitis may pose a serious threat on public health.

ANTIBIOGRAM OF METHICILLIN-RESISTANT Staphylococcus aureus (MRSA) STRAINS FROM KINDIRMO IN NASARAWA, NASARAWA STATE, NIGERIA

Dairy products have been found to be a major vehicle for the transmission of multidrug-resistant MRSA strains to man. This study determined the antibiogram of methicillin-resistant Staphylococcus aureus (MRSA) strains from traditionally-pasteurized dairy product (Kindirmo) in selected parts of Nasarawa, Nasarawa State, Nigeria. One hundred and sixty kindirmo samples were collected from vendors using random sampling from the areas selected for the study. Sample collection was between January 2021 and April 2021. Each sample was collected into sterile screwed-capped plastic bottle and labeled appropriately. Standard microbiological procedures were used in isolating and identifying MRSA strains from the samples. Characterisation of the MRSA strains was carried out using Microgen® kits. The MRSA strains were evaluated for their susceptibility to cefoxitin (30µg), clindamycin (2µg), chloramphenicol (30µg), doxycycline (30µg), gentamicin (10µg), sulphamethoxazole/trimethoprim (25µg), tobramycin (30µg), and vancomycin (30µg), using the Kirby-Bauer technique. Of the 160 samples examined, eight MRSA strains were obtained, giving a prevalence of 5.0%. All of the MRSA strains were resistant to cefoxitin (0-1mm); 62.5% were resistant to tobramycin (7-11mm); and 25.0% were resistant to chloramphenicol (4-10mm). Five (5) antibiotic resistant phenotypes were recorded among the MRSA strains. The occurrence of MRSA in Kindirmo as recorded in this study, suggest that, the consumption of the product constitute a hazard to consumers. Basic hygiene requirements during production and selling of the product should be imposed by relevant authorities. This will go a long way in ensuring the safety of the product.

Antimicrobial Susceptibility Profile of Methicillin-Resistant Staphylococcus Aureus Isolated from Clinical Samples at Bac Ninh Provincial General Hospital, Vietnam.

Staphylococcus aureus, including methicillin-resistant Staphylococcus aureus (MRSA) strain, can become resistant to all classes of clinically available antibiotics and causes skin infections and severe infections in the lungs, heart, and bloodstream. The study aimed to evaluate antimicrobial susceptibility patterns and MRSA exhibiting multidrug resistance obtained through a microbiological culture of clinical specimens at Bac Ninh Provincial General Hospital in Bac Ninh Province, Vietnam. We employed a cross-sectional analysis at Bac Ninh Provincial General Hospital in Vietnam. 15,232 clinical samples from inpatients were examined. S. aureus isolates were identified using established protocols and tested for MRSA and antibiotic susceptibility. Data was analyzed using R software, with statistical calculations to assess associations between variables. Staphylococcus aureus was isolated from 417 samples (2.7%), with 77.2% being MRSA and 22.8% methicillin-susceptible Staphylococcus aureus (MSSA). Significant sources of MRSA were wounds (64.6%) and the surgical unit (50%) according to sample types and hospital wards, respectively. S. aureus showed high resistance rates, the highest being azithromycin (83.2%), and was fully susceptible to vancomycin. Among 294 multidrug-resistant (MDR) strains, the prevalence was 82.0% in MRSA and 18.0% in MSSA. The study highlights widespread antimicrobial resistance among MRSA isolates from a provincial hospital in Vietnam, emphasizing the urgent need for antibiotic surveillance, formulation of antibiotic policies, and preventive measures to tackle the increasing prevalence of multidrug-resistant MRSA.

Molecular characterization of methicilin-resistant Staphylococcus aureus strain BM85 isolated from a Vietnamese patient with bloodstream infection

Methicillin-resistant Staphylococcus aureus (MRSA) is a threat to global health due to its resistance to β-lactam antibiotics and many other antibiotic classes developed via both intrinsic and acquired mechanisms. In this study, molecular characteristics related to antibiotic resistance of MRSA strain BM85 were investigated by whole-genome sequencing of a sample isolated from a patient with bloodstream infection at Bach Mai Hospital, Vietnam. Antibiotic susceptibility testing was also performed to determine the correlation between the presence of antibiotic-resistant genes and resistance phenotypes. Genomic analyses showed that the MRSA strain BM85 belonged to the major community-acquired (CA)-MRSA lineage ST59 originating from Taiwan. The strain harbored Staphylococcal Cassette Chromosome mec (SCCmec) type Vb (5C2&5) and Panton-Valentine leukocidin (PVL). Additionally, MRSA strain BM85 also possessed various antibiotic-resistant genes including tet38, tetK, blaZ, mecA, aph(3')-IIIa, aacA-aphD, and ermB which were located on mobile genetic elements MESPM1, Tn553-Tn4001 transposon, and a plasmid carrying the tetK gene, which was responsible for tetracycline resistance. The genotypic-resistant results were concordant with the phenotypic-resistant profile in which MRSA strain BM85 was resistant to penicillin, cefoxitin, gentamicin, kanamycin, tobramycin, erythromycin, and tetracycline. The sequencing data for the MRSA strain BM85 was deposited in GenBank, NCBI under accession number: BioProject PRJNA857185. In conclusion, the acquisition of the foreign genetic elements associated with antibiotic resistances through horizontal gene transfer mechanisms was the key driver of multidrug resistance in the multidrug-resistant MRSA strain BM85.

Complete Genome Sequence and Analysis of a ST573 Multidrug-Resistant Methicillin-Resistant Staphylococcus aureus SauR3 Clinical Isolate from Terengganu, Malaysia

Methicillin-resistant Staphylococcus aureus (MRSA) is a World Health Organization-listed priority pathogen. Scarce genomic data are available for MRSA isolates from Malaysia. Here, we present the complete genome sequence of a multidrug-resistant MRSA strain SauR3, isolated from the blood of a 6-year-old patient hospitalized in Terengganu, Malaysia, in 2016. S. aureus SauR3 was resistant to five antimicrobial classes comprising nine antibiotics. The genome was sequenced on the Illumina and Oxford Nanopore platforms and hybrid assembly was performed to obtain its complete genome sequence. The SauR3 genome consists of a circular chromosome of 2,800,017 bp and three plasmids designated pSauR3-1 (42,928 bp), pSauR3-2 (3011 bp), and pSauR3-3 (2473 bp). SauR3 belongs to sequence type 573 (ST573), a rarely reported sequence type of the staphylococcal clonal complex 1 (CC1) lineage, and harbors a variant of the staphylococcal cassette chromosome mec (SCCmec) type V (5C2&5) element which also contains the aac(6')-aph(2″) aminoglycoside-resistance genes. pSauR3-1 harbors several antibiotic resistance genes in a 14,095 bp genomic island (GI), previously reported in the chromosome of other staphylococci. pSauR3-2 is cryptic, whereas pSauR3-3 encodes the ermC gene that mediates inducible resistance to macrolide-lincosamide-streptogramin B (iMLSB). The SauR3 genome can potentially be used as a reference genome for other ST573 isolates.

Multidrug-Resistant Methicillin-Resistant Staphylococcus aureus Associated with Hospitalized Newborn Infants.

Multidrug resistance (MDR) is a significant challenge in healthcare management, and addressing it requires a comprehensive approach. In this study, we employed a combination of phenotypic and genotypic approaches, along with whole genome sequencing (WGS) to investigate five hospital-associated MDR methicillin-resistant Staphylococcus aureus (MRSA) strains that were isolated from newborn infants. Our analysis revealed the following for the MDR-MRSA strains: SauR31 was resistant to three antimicrobial classes; SauR12, SauR91 and SauR110 were resistant to four antimicrobial classes; and SauR23 exhibited resistance to seven classes. All the MDR-MRSA strains were capable of producing slime and biofilms, harbored SCCmec type IV, and belonged to different spa types (t022, t032, and t548), with varying profiles for microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) and virulence genes. The WGS data for the MDR SauR23 and SauR91 strains revealed that most of the antimicrobial resistance genes were present in the chromosomes, including blaZ, mecA, norA, lmrS, and sdrM, with only the ermC gene found in a small (<3 kb) plasmid. The presence of MDR-MRSA strains among neonates raises public concern, hence implementation of multifaceted interventions is recommended to address this issue. In addition, metadata is needed to improve the investigation of antimicrobial resistance genes in MDR isolates.

Incidence of Methicillin-Resistant Staphylococcus Aureus (MRSA) Recovered from Patients with Urinary Tract Infections in Zakho City/ Kurdistan-Iraq

The prevalence of Staphylococcus aureus (S. aureus) among patients with urinary tract infections (UTIs) has become a significant cause of morbidity in all age groups. The aim of the current study was to identify S. aureus with methicillin-resistant S. aureus (MRSA). Moreover, it aimed to determine their antimicrobial susceptibility patterns and to detect the presence of the mecA, lukPV and icaA genes in isolated S. aureus among UTIs patients. A total of 402 urine samples were collected from patients diagnosed with UTIs aged (less than 80 years) at Zakho General Hospital in Zakho City, from August 2021 to March 2022. From these samples, a total of 37 (12.6%) S. aureus was identified and molecularly confirmed by the nuc gene. A high prevalence of MRSA 28 (75.7%) was identified from these isolates S. aureus by Oxacillin sensitive test and confirmed by mecA gene. Females were highly infected with UTIs than males, and most cases were in chronic condition and married. In addition, 18 (64.3%) and 21 (75%) of these isolates S. aureus were harbored luk-PV and icaA genes, respectively. There were widespread of antimicrobial resistance patterns for these bacteria. Isolated MRSA were highly sensitive to Imipenem. Interestingly, a significant positive correlation between mecA and both virulence marker genes (luk-PV and icaA) found in MRSA with UTIs. Conclusion, the data demonstrated, for the first time, alarming emergence of multidrug-resistant MRSA isolated from UTIs of community-acquired in Kurdistan Region-Iraq. Further studies are required in other cities to report whether or not MRSA is the cause of UTI patients in Iraqi Kurdistan.

A Study on the Prevalence and Susceptibility Pattern of MRSA in a Tertiary Care Hospital of Haroti Region

Background and Aims: Emerging antimicrobial resistance is one of the major public health threats worldwide. It can result in increased morbidity and mortality rates along with increased treatment costs and hospitalization stays. Methicillin-resistant Staphylococcus aureus (MRSA) has become a global challenge. It is a major cause of nosocomial and community-acquired infections. Its prevalence varies with country and within hospitals within a country. The current study estimates the prevalence of MRSA.&#x0D; Materials and Methods: A total of 162 Staphylococcus aureus strains were isolated from various clinical specimens, and antibiotic susceptibility tests and identification by cefoxitin disc (30 μg) were performed as per Clinical and Laboratory Standards Institute guidelines.&#x0D; Results: Among 162 Staphylococcus aureus 92 isolates were found to be MRSA. The highest rate of resistance was detected for penicillin (100), followed by erythromycin (97%), clindamycin (57%), tetracycline (13%), sulfamethoxazole-trimethoprim (SXT) (55%), ciprofloxacin (23%), and gentamicin (2%). All of the isolates were susceptible to linezolid and vancomycin.&#x0D; Conclusions: Treatment of multi-drug resistant MRSA is still problematic because of the limited choice of antibiotic. This analysis will assist clinicians to choose an appropriate course of action for MRSA infections.

Occurrence of Methicillin-resistant Staphylococcus aureus (MRSA) From Dairy Cows in Kebbi, Nigeria

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is an important healthcare-associated pathogen that is also an emerging zoonosis. Objectives: A cross-sectional study was conducted to investigate the prevalence of MRSA in dairy cattle farms in Kebbi, North-Western Nigeria. Methods: A total of 200 milk samples, consisting of 50 samples each from lactating cows, were collected and used. The samples were analyzed using bacterial culture and isolation and polymerase chain reaction (PCR). Suspected MRSA isolates were identified via PCR detection of the mecA gene, and antimicrobial susceptibility profiles of the isolates were assessed using the Kirby-Bauer disk diffusion method. Results: Of the two hundred milk samples examined, the prevalence of MRSA was recorded at 18% (36/200) using phenotypic and genotypic characterization methods. The susceptibility to vancomycin was observed in all isolates, and they had a multiple antibiotic resistance (MAR) index of &gt;0.4. Conclusion: This investigation showed the colonization of healthy dairy cows by multidrug-resistant MRSA.

662. In vitro antibacterial activity of contezolid compared to linezolid and vancomycin in clinical isolates from China

Abstract Background Linezolid and vancomycin are insufficient in the treatment of drug-resistant Gram-positive bacteria due to adverse drug reactions and drug resistance, and new antibiotics are needed, especially for patients with myelosuppression and vancomycin-resistant Enteroccocus (VRE) infection. Contezolid (CZD) is a novel oral oxazolidinone with potent activity against Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) and VRE. We evaluate the in vitro antibacterial activity of contezolid compared to linezolid and vancomycin in Gram-positive clinical isolates. Methods 176 clinical isolates were obtained from 176 sterile body fluids from patients at 3 tertiary care hospitals in China, and the minimal inhibitory concentrations (MICs) of contezolid, linezolid and vancomycin determined by broth microdilution assay. Results Contezolid exhibits excellent antibacterial activity against prevalent Gram-positive bacteria, Staphylococcus spp. and Enterococcus spp., including methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant and coagulase-negative Staphylococcus (MRCNS), and vancomycin-resistant Enterococcus (VRE). MIC90 values of contezolid were 2 mg/L for all MRSA and VRE isolates and 1 mg/L for MRCNS isolates. The antibacterial activity of contezolid against Staphylococcus spp., including S. aureus, was essentially similar to linezolid, and slightly higher than or similar to vancomycin. Antibacterial activity of contezolid against Enterococcus, including VRE, was similar to linezolid, while being slightly lower than for vancomycin in vancomycin-susceptible isolates. Consistent with the shared antibacterial mode of action, bacterial strains resistant to linezolid were cross-resistant to contezolid. Table 1.Antimicrobial susceptibility testing results of clinical bacterial strains (MICs, mg/L) Conclusion Contezolid, a novel oxazolidinone drug, exhibits potent in vitro antibacterial activity against clinical isolates of common Gram-positive pathogens, including multidrug-resistant (MDR) Gram-positive bacteria, MRSA, MRCNS, and VRE. Contezolid has antibacterial activity similar to standard-of-care antibiotics linezolid and vancomycin. Results suggest that contezolid can play an important role in treatment of MDR Gram-positive bacterial infections. Figure 1.Distribution of MICs of CZD or LZD against 48 strains of MRSAFigure 2.Distribution of MICs of CZD or LZD against 29 strains of MRCNSFigure 3.Distribution of MICs of CZD or LZD against 17 strains of VRE Disclosures All Authors: No reported disclosures.

Epidemiology and antibiotic susceptibility of multidrug-resistant Staphylococcus aureus in nosocomial and community acquired infections in southeastern Algeria

Bacterial nosocomial and community acquired infections due to the emergence of drug-resistant pathogens cause high morbidity and mortality worldwide in humans. Staphylococci are number one among the Gram-positive bacteria responsible for multiple infections in hospitals. In this survey, we determined the epidemiological aspects of Multi-drug-resistant – Methicillin resistant Staphylococcus aureus (MDR-MRSA) strains as well as antimicrobial susceptibility profile to different families of antibiotics. 80 MDR-MRSA strains were isolated from different pathological origins, during the period from August 2019 – August 2020. The isolation and the identification of S.aureus strains were based on conventional methods. Methicillin resistance was verified for each strains by using a disc of oxacillin (5μg) or cefoxitin (30μg) .The antibiotic susceptibility testing was performed by disc diffusion method on Mueller Hinton agar and evaluation of minimal inhibitory concentrations (MICs), according to Clinical &amp; Laboratory Standards Institute (CLSI). The study has shown that 80 MRSA strains were identified among the 125 S. aureus strains isolated (64 %). The majority of staphylococci come from pus (67,5%) followed by the blood culture (27,5%). 31,25% come mostly from intensive care unit with a percentage of 72% in adults, including 62,5% of cases recorded in females. The MRSA strains show multidrug resistance to different antibiotic families. We identified seven MRSA strains expressing reduced glycopeptides susceptibility. MRSA is important and serious pathogens in human infections, continued monitoring of susceptibility profiles of these pathogens to important antibiotics is required for a better therapeutic approach against nosocomial and community acquired infections caused by MDR-MRSA.

Clinical Implementation of Routine Whole-genome Sequencing for Hospital Infection Control of Multi-drug Resistant Pathogens.

Prospective whole-genome sequencing (WGS)-based surveillance may be the optimal approach to rapidly identify transmission of multi-drug resistant (MDR) bacteria in the healthcare setting. We prospectively collected methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), carbapenem-resistant Acinetobacter baumannii (CRAB), extended-spectrum beta-lactamase (ESBL-E), and carbapenemase-producing Enterobacterales (CPE) isolated from blood cultures, sterile sites, or screening specimens across three large tertiary referral hospitals (2 adult, 1 paediatric) in Brisbane, Australia. WGS was used to determine in silico multi-locus sequence typing (MLST) and resistance gene profiling via a bespoke genomic analysis pipeline. Putative transmission events were identified by comparison of core genome single nucleotide polymorphisms (SNPs). Relevant clinical meta-data were combined with genomic analyses via customised automation, collated into hospital-specific reports regularly distributed to infection control teams. Over 4 years (April 2017 to July 2021) 2660 isolates were sequenced. This included MDR gram-negative bacilli (n = 293 CPE, n = 1309 ESBL), MRSA (n = 620), and VRE (n = 433). A total of 379 clinical reports were issued. Core genome SNP data identified that 33% of isolates formed 76 distinct clusters. Of the 76 clusters, 43 were contained to the 3 target hospitals, suggesting ongoing transmission within the clinical environment. The remaining 33 clusters represented possible inter-hospital transmission events or strains circulating in the community. In 1 hospital, proven negligible transmission of non-multi-resistant MRSA enabled changes to infection control policy. Implementation of routine WGS for MDR pathogens in clinical laboratories is feasible and can enable targeted infection prevention and control interventions.

Occurrence and Antibiotic Resistance Profiles of Methicillin-Resistant Staphylococcus Aureus (Mrsa) in Layer Chickens in Kebbi, Nigeria

Abstract Antimicrobial resistance (AMR) is a global health threat, and antimicrobial use in animal production for growth enhancement or prophylaxis contributes to the development of AMR. A cross-sectional study was conducted to investigate the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in poultry and farm attendants in Kebbi, North-Western Nigeria. A total of 207 cloacal and nasal swabs were randomly collected from four farms comprising 50 samples from each poultry farm and only 7 samples from farm attendants. The samples were analysed using routine bacteriological culture and identification techniques. Presumptive MRSA isolates were confirmed by PCR assay and AMR profiles of the isolates were evaluated using the Kirby-Bauer disk diffusion method. Of the 207 samples examined, 37.5 % (75/200) of layer birds tested positive for MRSA and 71.4 % (5/7) of farm attendants were MRSA positive. All the isolates were susceptible to vancomycin, with an AMR index ˃ 0.3. The findings of this study indicated colonization of layer chickens and humans by multidrug resistant MRSA, thus highlighting the potential role of poultry sources of transmission of multidrug-resistant MRSA strains to humans and vice versa.

Rapid High-Throughput Assay Identified Gemcitabine and Derivatives As Potent Inhibitors Against Multidrug-Resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) are challenging pathogenic bacteria that can cause severe infection leading to high mortality rates. We found that both the oxacillin- and cefoxitin-resistant S. aureus strains isolated from clinic showed multidrug-resistant (MDR) characteristics. Through rapid high-throughput screen (HTS) of a compound library, gemcitabine and selen compounds were found to effectively inhibit S. aureus growth. For further improvement, we synthesized selen-containing gemcitabine that demonstrated relatively potent antimicrobial activity against several MDR MRSA in vitro. The HTS assay and gemcitabine selen derivative provided a useful tool to explore an effective molecular target to treat MDR MRSA.