Occurrence Of Methicillin-resistant Staphylococcus Aureus Research Articles

ST105 Lineage of MRSA: An Emerging Implication for Bloodstream Infection in the American and European Continents.

Sequence-type 5 (ST5) of methicillin-resistant Staphylococcus aureus (MRSA), harboring the staphylococcal chromosomal cassette mec type IV (SCCmecIV), was first detected in Portugal. It emerged as a significant cause of healthcare-associated (HA) infection in pediatric units and was hence named the pediatric clone. Another ST5 lineage, which carries SCCmecII, also prevailed in the USA and Japan for multiple years. More recently, another MRSA lineage, ST105-SCCmecII, part of the evolution of clonal complex 5 (CC5) MRSA, has emerged as the cause of hospital-acquired bloodstream infection outbreaks in countries including Portugal, the USA, and Brazil. This article reviews studies on the epidemiology and evolution of these newly emerging pathogens. To this end, a search of PUBMED from inception to 2024 was performed to find articles reporting the occurrence of ST105 MRSA in epidemiologic studies. A second search was performed to find studies on MRSA, CC5, ST5, and SCCmecII. A search of PUBMED from 1999 to 2024 was also performed to identify studies on the genomics and evolution of ST5, CC5, and ST105 MRSA. Further studies were identified by analyzing the references of the previously selected articles from PUBMED. Most articles on ST105 MRSA were included in this review. Only articles written in English were included. Furthermore, only studies that used a reliable genotyping method (e.g., whole genome sequencing, or MLST) to classify the CC5 lineages were selected. The quality and selection of articles were based on the consensus assessment of the three authors in independent evaluations. In conclusion, ST105-SCCmecII is an emerging MRSA in several countries, being the second/third most important CC5 lineage, with a relatively high frequency in bloodstream infections. Of concern is the increased mortality from BSI in patients older than 15 years and the higher prevalence of ST105-SCCmecII in the blood of patients older than 60 years reported in some studies.

Biofilm formation, agr typing and antibiotic resistance pattern in methicillin-resistant Staphylococcus aureus isolated from hospital environments.

Biofilm development significantly enhances the virulence of methicillin-resistant Staphylococcus aureus (MRSA), leading to severe infections and decreased susceptibility to antibiotics, especially in strains associated with hospital environments. This study examined the occurrence of MRSA, their ability to form biofilms, agr typing, and the antibiotic resistance profiles of biofilm-forming MRSA strains isolated from environmental surfaces at Mymensingh Medical College Hospital (MMCH). From 120 swab samples, 86 (71.67%) tested positive for S. aureus. MRSA was identified in 86 isolates using the disk diffusion technique, and by polymerase chain reaction (PCR), 56 (65.1%) isolates were confirmed to carry the mecA gene. The Crystal Violet Microtiter Plate (CVMP) test revealed that 80.35% (45 isolates) were biofilm-forming and 19.6% (11 isolates) were non-biofilm-forming. Out of 45 biofilm producer isolates 37.5% and 42.9% isolates exhibited strong and intermediate biofilm-forming characteristics, respectively. Molecular analysis revealed that 17.78% of MRSA isolates carried at least one gene related to biofilm formation, specifically icaA, icaB, and icaD genes were discovered in 13.33%, 8.89%, 6.67% of the MRSA isolates, respectively. In agr typing, the most prevalent group was agr I (71.11%), followed by group III (17.78%) and group II (11.11%). Group IV was not detected. The distribution of agr gene groups showed a significant difference among biofilm-forming isolates (p < 0.05). In agr group I, 18.75% of isolates carried the icaA gene, 12.5% carried the icaB gene, and 9.37% carried the icaD gene. Biofilm-forming genes were not detected in any of the isolates from agr groups II or III. There are no statistically significant differences between agr groups and the presence of these genes (p > 0.05). Antibiotic resistance varied significantly among agr groups, with agr group I displaying the highest resistance, agr group II, and agr group III exhibiting the least resistance (p < 0.05). Seventy-three (73.3%) of the isolates were multi-drug resistant, with agr group I displaying nineteen MDR patterns. The occurrence of MRSA in hospital environments and their capacity to form biofilm raises concerns for public health. These findings support the importance of further research focused on agr quorum sensing systems as a basis for developing novel antibacterial agents.

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.

The efficacy of telavancin in comparison with linezolid on endotracheal tube biofilm in pigs with methicillin-resistant Staphylococcus aureus pneumonia

The effect of systemic treatment of ventilator-associated pneumonia (VAP) with telavancin, a semisynthetic lipoglycopeptide with good penetration in vitro biofilms, has not been tested in vivo during mechanical ventilation. This study examined the efficacy of telavancin compared with linezolid against endotracheal tube (ETT) biofilms in a porcine model of methicillin-resistant Staphylococcus aureus (MRSA) VAP. VAP was induced in 18 pigs by instilling 107 colony-forming units (CFU/mL) of an MRSA strain susceptible to telavancin and linezolid into each pulmonary lobe. Randomization into three groups was done at pneumonia diagnosis: control (IV glucose 0.5% solution q24); linezolid (10 mg/kg q12) and telavancin groups (22.5 mg/kg q24). After 72 h of MV, data regarding bronchoalveolar lavage (BAL), tracheal aspirate (TA), ETT MRSA biofilm load and thickness measured by scanning electron microscopy were obtained. All 18 pigs completed the study. MRSA was isolated in 100% of ETTs from the control and linezolid groups and in 67% from the telavancin group. Telavancin treatment presented a lower MRSA load compared to the control and linezolid treatments (telavancin median [interquartile range (IQR)] = 1.94 [0.00-5.45], linezolid 3.99 [3.22-4.68] and control 4.93 [4.41-5.15], P = 0.236). Telavancin treatment also resulted in the lowest biofilm thickness according to the SEM (4.04 [2.09-6.00], P < 0.001). We found a positive correlation between ETT and BAL load (rho = 0.511, P = 0.045). In our VAP model, systemic telavancin treatment reduced ETT MRSA occurrence, load, and biofilm thickness. Our findings may have a bearing on ICU patients' clinical outcomes.

No Changes in the Occurrence of Methicillin-Resistant Staphylococcus aureus (MRSA) in South-East Austria during the COVID-19 Pandemic.

Methicillin-resistant Staphylococcus aureus (MRSA) is a universal threat. Once being well established in the healthcare setting, MRSA has undergone various epidemiological changes. This includes the emergence of more aggressive community-acquired MRSA (CA-MRSA) and the occurrence of MRSA which have their origin in animal breeding, called livestock-associated MRSA (LA-MRSA). Emergence of new clones as well as changes in the occurrence of some clonal lineages also describes the fluctuating dynamic within the MRSA family. There is paucity of data describing the possible impact of the COVID-19 pandemic on the MRSA dynamics. The aim of the study was the analysis of MRSA isolates in a three-year time period, including the pre-COVID-19 years 2018 and 2019 and the first year of the pandemic 2020. The analysis includes prevalence determination, antibiotic susceptibility testing, spa typing, and detection of genes encoding the PVL toxin. The MRSA rate remained constant throughout the study period. In terms of a dynamic within the MRSA family, only a few significant changes could be observed, but all except one occurred before the start of the COVID-19 pandemic. In summary, there was no significant impact of the COVID-19 pandemic on MRSA in Austria.

Distribution of Macrolide, Lincosamide, and Streptogramin B and Detection of erm Genes in Staphylococcus aureus from Wounds in Uyo, Nigeria

The increasing resistance to macrolide, lincosamide, and streptogramin B (MLSB) among methicillin-resistant Staphylococcus aureus (MRSA) is a challenge. The study determined the constitutive and inducible MLSB resistance and erm genes in S. aureus from wounds using the erythromycin-clindamycin D-zone test and a multiplex polymerase chain reaction assay, respectively. Of the 260 patients recruited in the study, S. aureus was isolated from the wounds of 102 patients, giving a prevalence rate of 39.2%. Of the 102 S. aureus isolates, 32.4% were methicillin-sensitive S. aureus (MSSA), and 67.6% were MRSA. The prevalence of S. aureus in wounds was higher in females (39.8%) than in males (38.4%). The highest prevalence of S. aureus was found in divorce patients (59.1%) and those residing in urban areas (39.7%). There was no statistical difference between the occurrence of MRSA and MSSA in wounds based on the sex (p = 0.97), age (p = 0.08), and marital status (p = 0.41) of the patients. All (100%) MRSA were resistant to Cefoxitin, and chloramphenicol, while ˂ 50% of MRSA were resistant to Tetracycline, Ciprofloxacin, and Gentamycin. Of the 69 MRSA isolates from the wounds, 21.7% and 26.1% were iMLSB and cMLSB phenotypes, respectively. Nine (9) MSSA were iMLSB phenotypes, and eight MSSA were cMLSB phenotypes. Among the 12 representative isolates, three (3) MRSA and one (1) MSSA isolate possessed the ermC gene. This study has revealed that screening tests for iMLSB-resistant S. aureus strains are critical for the therapeutic management of wound infections caused by S. aureus.

Biofilm Formation and Antimicrobial Susceptibility Pattern of &lt;i&gt;Staphylococcus aureus&lt;/i&gt; Clinical Isolates from Two Healthcare Facilities in Zaria

Background: Antibiotic resistance is a public health challenge worldwide. There is a huge global concern about the increased drug- resistant S. aureus and the development of multiple resistance to several drugs. A well-designed surveillance study has been found to be a fundamental approach in the control of antimicrobial resistance.&#x0D; Objective: This study investigated the biofilm formation and antimicrobial susceptibility pattern of Staphylococcus aureus from two healthcare facilities in Zaria.&#x0D; Methods: A total of 200 presumptive Staphylococcal isolates from clinical specimens were collected and identified by conventional methods. Staphylococcus aureus isolates were tested against a panel of antibiotics using the modified Kirby- Bauer disk diffusion method, Methicillin-resistant Staphylococcus aureus (MRSA) were tested using cefoxitin disk, and Micro broth dilution method for Vancomycin Minimum Inhibitory Concentration (MIC). The biofilmforming ability of the isolates were analyzed quantitatively using the microtitre plate method.&#x0D; Results: Of the 200 presumptive staphylococcal isolates, 22(11%) were Staphylococcus aureus. The antibiotic resistance pattern of the isolates shows high resistance to tigecycline (100%), vancomycin (100%), clindamycin (40.9%), and tetracycline (40.9). The occurrence of MRSA in this study was 18.8% and MDR (was 68.2%). The biofilm-forming ability of the Staphylococcus aureus isolates is; weak biofilm formers 16 (72.7%), moderate biofilm formers 5 (22.7%), and strong biofilm former 1 (4.5%).&#x0D; Conclusion: There is need for more research to ascertain the relationship between biofilm formation and antimicrobial resistance in Staphylococcus aureus. Close monitoring of antimicrobial resistance is necessary as it helps to design tangible actions that will yield the greatest impact to control the spread of resistant organisms.

Mandatory Notification of Panton-Valentine Leukocidin-Positive Methicillin-Resistant Staphylococcus aureus in Saxony, Germany: Analysis of Cases from the City of Leipzig in 2019.

In Germany, Saxony is the only federal state where the detection of a Panton-Valentine Leukocidin (PVL)-positive Methicillin-resistant Staphylococcus aureus (MRSA) has to be notified to the local health authority (LHA). The LHA reports the case to the state health authority and introduces concrete infection control measures. We analyzed isolates from the respective cases in 2019, which were collected in local microbiological laboratories and sent to the National Reference Centre (NRC) for Staphylococci and Enterococci for strain characterization and typing. Antibiotic resistance testing was done by broth microdilution. Molecular characterization was performed using spa and SCCmec typing, MLST, and the PCR detection of marker genes associated with distinct MRSA lineages. Demographic and clinical data of the individual cases were assessed and the LHA performed epidemiological investigations. Thirty-nine (index) persons, diagnosed with a PVL-positive MRSA, were initially reported to the LHA. Most patients suffered from skin and soft-tissue infections (SSTI). For 21 of the index cases, household contacts were screened for MRSA. Seventeen out of 62 contacts were also colonized with a PVL-positive MRSA. The median age of altogether 58 individuals was 23.5 years. In over half of the cases, the home country was not Germany and/or a history of travel or migration was reported. Molecular characterization revealed the presence of various epidemic community-associated MRSA lineages, with "USA300", including the North American Epidemic (ST8-MRSA-IVa) and the South American Epidemic Clone (ST8-MRSA-IVc), the "Sri Lankan Clone" (ST5-MRSA-IVc), and the "Bengal Bay Clone" (ST772-MRSA-V) being more prevalent. In eight out of nine households, the contact persons were colonized with the same clone as the respective index case, suggesting a close epidemic and microbiological link. The obligation to report PVL-positive MRSA enables us to detect the occurrence of PVL-producing MRSA and its spread in the population as early as possible. Timely detection allows the targeted deployment of reliable anti-infective measures.

Clonal dissemination of successful emerging clone mecA-MRSA t304/ST6 among humans and hedgehogs in the Helsinki metropolitan area in Finland

Methicillin-resistant Staphylococcus aureus (MRSA) carrying mecC gene (mecC-MRSA) is frequently reported among European hedgehogs (Europeaus erineaus) due to co-evolutionary adaptation to dermatophyte infection in European hedgehogs. The occurrence of MRSA in European hedgehogs in Finland is unknown. Consequently, we investigated the occurrence of MRSA in wild hedgehogs from urban Helsinki metropolitan area in 2020–2021 and applied whole genome sequencing (WGS) to further characterize the studied isolates and compared them with human clinical MRSA isolates. Altogether 115 dead hedgehogs were screened for MRSA using selective cultivation methods. Presumptive MRSA isolates were tested for antimicrobial susceptibility and confirmed MRSA isolates were further characterized by spa-typing and WGS. Hedgehog derived MRSA isolates were compared with clinical human MRSA isolates using core genome multilocus sequence typing (cgMLST). In total MRSA was recovered from 11 out of 115 (10%) hedgehogs. Among these four different spa types (t304; n = 4, t8835; n = 4, t5133; n = 2 and t622; n = 1) and three different sequence types (STs) (ST6; n = 6, ST7663; n = 4 and ST2840; n = 1) were identified. From the studied MRSA isolates seven harboured the mecA gene (mecA-MRSA) and four were identified as mecC-MRSA. All mecA-MRSA isolates carried immune evasion cluster genes, and one isolate was positive for Panton-Valentine leukocidin. cgMLST comparison revealed close genetic relatedness among three hedgehog and two human mecA-MRSA isolates all belonging to t304/ST6. Our results suggest a clonal dissemination of a successful MRSA clone among humans and hedgehogs. Further studies are warranted to investigate the sources and dissemination of such clone in urban environments. We observed a relatively low occurrence of mecC-MRSA in Finnish hedgehogs.

First Evidence of the Presence of the Causative Agent of Caseous Lymphadenitis-Corynebacterium pseudotuberculosis in Dairy Products Produced from the Milk of Small Ruminants.

This study focused on the detection and quantification of selected bacteria and on the presence of enterotoxin genes in milk and dairy products from sheep and goat farms in the Czech Republic using quantitative real-time PCR (qPCR) and multiplex PCR (PCR). The presence of Corynebacterium pseudotuberculosis (CP), Mycobacterium avium subsp. paratuberculosis (MAP), Listeria monocytogenes, Staphylococcus aureus, S. aureus enterotoxin genes and methicillin-resistant Staphylococcus aureus (MRSA) was determined in 18 milk samples, 28 fresh cheeses, 20 ripened cheeses and 14 yoghurts. The serological status of the herds in relation to CP and MAP was taken into account. The most frequently detected bacterium was S. aureus (48.8%), and subsequent PCR revealed 11 MRSA positive samples. The S. aureus enterotoxin genes seg, sei and sec were detected in two goat cheeses. Cheese samples showed a statistically higher risk of SA and MRSA occurrence. CP (8.8%) and MAP (13.8%) were detected by qPCR on two different seropositive farms. Cultivation of qPCR positive CP samples on agar plates supplemented with potassium tellurite showed the presence of viable bacterium. The results obtained confirmed the necessity of monitoring the infectious status of dairy animals and rapid diagnosis of bacterial pathogens in milk and dairy products.

Role of milk and milk products in the spread of methicillin-resistant Staphylococcus aureus in the dairy production chain.

Milk and milk products can harbor a multiple varieties of microorganisms. Therefore, they can be an important source of foodborne pathogens, including multidrug-resistant bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) causes a wide spectrum of infections both in animals and humans. Over the last two decades, the presence of MRSA in foods and food-producing animals, including milk and milk products, has been frequently reported worldwide, raising public health concerns. In order to monitor and prevent foodborne MRSA contamination, it is necessary to understand their sources, the pheno/genotypic characteristics of the strains, and their transmission dynamics. In this review, studies conducted worldwide were summarized in order to assess the prevalence and diversity of MRSA circulating in milk and milk products. The risk factors for the occurrence of MRSA in milk and milk products were also discussed with preventive and control measures to avoid MRSA contamination in the dairy food chain.

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.

The prevalence, genetic diversity and antibiotic resistance of Staphylococcus aureus associated with subclinical bovine mastitis in Balikesir, Turkey

Subclinical mastitis caused by Staphylococcus aureus is very common in dairy cows and creates serious problems on dairy farms. In this study, we investigated the prevalence, genetic diversity and antimicrobial resistance of S. aureus from subclinical bovine mastitis on 12 dairy herds in Balikesir province of Turkey, by SCCmec and spa typing. Ninety-five isolates of S. aureus were isolated from 725 subclinical mastitic milk samples that exceeded the somatic cell count (SCC) limit of 4 x 105 cell/mL. The frequency of MRSA (methicillin-resistant Staphylococcus aureus) and MSSA (methicillin-sensitive S. aureus) was 6.3% (6 isolates) and 93.68% (89 isolates) respectively. SCCmec types of MRSA isolates were community-associated CA-MRSA type IVb (4 isolates) and type IVd (two isolates), while the spa types were T 005 and T 5163 (three isolates from each). The resistance rate of MRSA isolates was 100% for oxacillin and cefoxitin, 83% for penicillin, ampicillin, clindamycin, erythromycin and 66% for gentamicin and trimethoprim/sulfamethoxazole. However, compared to MRSA, the resistance of MSSA isolates was relatively lower. This study supported the scientific data on the occurrence of MRSA and MSSA in subclinical mastitis, and highlighted the need for preventive measures to eliminate or decrease S. aureus contamination of milk in dairy herds.

Nasal colonization of methicillin resistant staphylococcus aureus among slaughterhouse workers in Dar es salaam, Tanzania

Introduction: Methicillin resistant Staphylococcus aureus (MRSA) is a zoonotic pathogen that is associated with serious and sometimes fatal infections in humans. The pathogen has ability to acquire resistance to most antibiotics. Working in slaughterhouses increase the chance of workers to contract this pathogen. This study aimed to determine the prevalence of MRSA and its associated factors among slaughterhouse workers in Dar es Salaam, Tanzania. Methods: A cross-sectional study was conducted from June-July 2018 involving workers from 4 registered slaughterhouses. Social demographics and other information was collected using a semi-structured questionnaire. Swabs were collected and inoculated in Mannitol salt agar for S. aureus isolation. The isolates were tested for antimicrobial susceptibility using 10µg Oxacillin discs implanted on Muller Hinton Agar plates. Binary logistic regression was employed to determine the association between prevalence of MRSA and independent variables. Results: MRSA was isolated from 39,2% of the 258 enrolled slaughterhouse workers. MRSA colonization was more likely in persons who have been working for more than 21 years (p=0,014) and smokers (p=0,02). On-job training (adjOR=0,417; 95% CI: 0,202-0,858, p= 0,018) was protective against MRSA nasal colonization. Conclusion: Our study has demonstrated the occurrence of MRSA in slaughterhouse workers in Dar es salaam, Tanzania. It is more prevalent in persons who have been working for a long time in slaughterhouses. In addition, provision of on-job training is protective against MRSA nasal colonization. More studies are required to confirm whether the MRSA detected were livestock-associated.

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.

Higher seasonal temperature enhances the occurrence of methicillin resistance of Staphylococcus aureus in house flies (Musca domestica) under hospital and environmental settings.

Antimicrobial resistance (AMR) emergence in commensal and pathogenic bacteria is a global health issue. House flies (Musca domestica) are considered as biological and mechanical vectors for pathogens causing nosocomial infections, including methicillin-resistant Staphylococcus aureus (MRSA). However, the prevalence of antimicrobial resistance and the role of temperature on the occurrence of Staphylococcus aureus and MRSA in house flies in a hospital environment have not been studied. A total of 400 house flies were collected in winter and summer from four hospital-associated areas in Mymensingh, Bangladesh. Detection of S. aureus and MRSA in flies was done by culturing, staining, and PCR methods targeting nuc and mec genes (mecA and mecC), respectively. Disc diffusion test was used to detect resistance phenotype against six antimicrobials. Logistic regression models were constructed to assess the effect of temperature on the frequency of antimicrobial resistance, and on the presence of the nuc and mecA genes, and location of samples in and around a hospital environment. By PCR, S. aureus was detected in 208 (52%) samples. High frequencies of resistance (≥ 80% of isolates) to amoxicillin, azithromycin, and oxacillin were observed by disk diffusion test. Increase in temperature had a positive effect on the occurrence of S. aureus and MRSA isolates as well as on their resistance to individual and multiple antimicrobials. Among the study areas, hospital premises had increased odds of having S. aureus. Increased temperature of summer significantly increased the occurrence of MRSA in house flies in and around the hospital environment, which might pose a human and animal health risk.

Prevalence of Mastitis and Phenotypic Characterization of Methicillin-Resistant Staphylococcus aureus in Lactating Dairy Cows of Selected Dairy Farms in and Around Adama Town, Central Ethiopia.

Background:The emergence of Methicillin resistant Staphylococcus aureus (MRSA) poses a serious public health threat. Strains of Staphylococcus aureus resistant to β-lactam antibiotics are known as MRSA. MRSA has gained attention as community pathogen. MRSA has been increasingly reported as emerging problem in veterinary medicine. However, little is known in Ethiopia. This study was, therefore, conducted to identify MRSA, to determine its drug susceptibility patterns, and mastitis infection in dairy cattle in and around Adama town, Central Ethiopia.Methods:A cross-sectional study was conducted to estimate the occurrence of MRSA in mastitic dairy cows in and around Adama town, central Ethiopia. A total of 384 lactating cows were included from the conveniently selected dairy farms in the study area. Approximately 10 ml of milk was aseptically collected from clinical and subclinical mastitic cows into sterile universal bottles after discarding the first 3 milking streams. Then, Staphylococcus aureus was isolated using the conventional bacteriological procedure. Resistance to methicillin was detected using the Kirby-Bauer disc diffusion antibiotic susceptibility method. Oxacillin disc was used to detect methicillin resistant Staphylococcus aureus strains. Antimicrobial susceptibility test was conducted against MRSA strains using streptomycin (S, 10 µg), amoxicillin (Am, 25 µg), kanamycin (k, 30 µg), nalidixic acid (NA, 30 µg), oxytetracycline (OT, 30 µg) sulphonamide (S, 300 µg) and ceftriazole (CRO, 30 µg).Results:The study found that the prevalence of mastitis was 121(31.5%). Among this 37(30.6%) were clinical mastitis and 84 (69.4%) of them were sub-clinical mastitis. Of 121 mastitis cases, Staphylococcus aureus was isolated in 37 (30.6%) of mastitic cow milk samples. The prevalence of mastitis was significantly affected by breed, age, floor type and hygienic status of the milkers (P < .05). Moreover, 32.4% of Staphylococcus aureus isolates were resistant to oxacillin. A total of 75% percent of MRSA isolates were resistant to amoxicillin, 66.7% were resistant to oxytetracycline, and 50% were resistant to sulphonamide. However, 75% of MRSA isolates were susceptible to kanamycin, 58.3% were susceptible to streptomycin, and 50% were susceptible to nalidixic acid.Conclusion:The study revealed that relatively high number of strains are resistant to the antibiotics commonly used in the therapeutic protocol of many human and animal infections. Therefore, antimicrobial susceptibility test should be carried out at a regular basis and proper hygienic practices should be introduced at farm level. Creating public awareness about transmission, prevention and control of MRSA should also be considered.

Colonization and Infection With MRSA and CRKP and Its Result in an Increased Mortality Rate Within the Intensive Care and High-Dependency Units in Barbados

Background: Methicillin-resistant Staphylococcus aureus(MRSA) and carbapenem-resistant Klebsiella pneumoniae (CRKP) are a growing public health concern in Barbados. Intensive care and critically ill patients are at a higher risk for MRSA and CRKP colonization and infection. MRSA and CRKP colonization and infection are associated with a high mortality and morbidly rate in the intensive care units (ICUs) and high-dependency units (HDUs). There is no concrete evidence in the literature regarding MRSA and CRKP colonization and infection in Barbados or the Caribbean. Objectives: We investigated the prevalence of MRSA and CRKP colonization and infection in the patients of the ICU and HDU units at the Queen Elizabeth Hospital from 2013 to 2017. Methods: We conducted a retrospective cohort analysis of patients admitted to the MICU, SICU, and HDU from January 2013 through December 2017. Data were collected as part of the surveillance program instituted by the IPC department. Admissions and weekly swabs for rectal, nasal, groin, and axilla were performed to screen for colonization with MRSA and CRKP. Follow-up was performed for positive cultures from sterile isolates, indicating infection. Positive MRSA and CRKP colonization or infection were identified, and patient notes were collected. Our exclusion criteria included patients with a of stay of &lt;48 hours and patients with MRSA or CRKP before admission. Results: Of 3,641 of persons admitted 2,801 cases fit the study criteria. Overall, 161 (5.3%) were colonized or infected with MRSA alone, 215 (7.67%) were colonized or infected with CRKP alone, and 15 (0.53%) were colonized or infected with both MRSA and CRKP. In addition, 10 (66.6%) of patients colonized or infected with MRSA and CRKP died. Average length of stay of patients who died was 50 days. Conclusions: The results of this study demonstrate that MRSA and CRKP cocolonization and coinfection is associated with high mortality in patients within the ICU and HDU units. Patients admitted to the ICU and HDU with an average length of stay of 50 days are at a higher risk for cocolonization and coinfection with MRSA and CRKP. Stronger IPC measures must be implemented to reduce the spread and occurrence of MRSA and CRKP.Funding: NoneDisclosures: None

Occurrence and characterisation of methicillin-resistant Staphylococcus aureus isolated from bovine milk in Hungary.

The last surveys on methicillin-resistant Staphylococcus aureus (MRSA) isolated from bovine milk in Hungary took place in the 2000s. To elucidate the genetic variability and to estimate the burden of the pathogen, MRSA from our strain collection and prospectively collected Staphylococcus aureus (SA) isolates originating from two milk hygiene laboratories were investigated. Between 2003 and 2018, 27 MRSA strains originating from 10 dairy farms were deposited and characterised. Most strains (n = 20) belonged to ST1-t127-SCCmecIV and were recovered from three unrelated farms. From other farms, variable genotypes were identified sporadically: ST22-t032-SCCmecIV from three farms; a newly described double locus variant of ST97, ST5982-t458-SCCmecIV from two farms; and ST398-t011-SCCmecIV and ST398-t011-SCCmecV from two respective farms. The prospective screening of 626 individual SA isolates originating from 42 dairy farms resulted in four (0.48 %) MRSA strains from three (7.14 %) farms. All MRSA isolates belonged to the clonal complex 398 and a novel spa-type t19251 was also identified. Most isolates were resistant to three or more antimicrobial classes. The occurrence and significance of MRSA of dairy origin seems to be unchanged in the past decade in Hungary. However, the low host specificity and multiresistance of the identified genotypes calls for periodic revision on the role and distribution of the pathogen in the Hungarian dairy sector.

Antimicrobial Resistance and Virulence of Methicillin-Resistant Staphylococcus aureus from Human, Chicken and Environmental Samples within Live Bird Markets in Three Nigerian Cities.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major threat to public health. This study investigated the occurrence of MRSA in humans, chickens, chicken meat and environmental samples within poultry farms and live bird markets in southwestern Nigeria. Methods: MRSA were isolated using selective culture and tested for antimicrobial susceptibility by broth microdilution. Selected isolates were characterized by whole genome sequencing (WGS). From WGS data, spa, dru, multilocus sequence typing (MLST) and SCCmec types, but also virulence and antimicrobial resistance genes, were identified. Results: Fifty-six MRSA isolates were detected in 734 samples. They showed resistance to β-lactams (100%), tetracycline (60.7%), ciprofloxacin (33.9%), erythromycin (28.6%), gentamicin (32.1%), and trimethoprim/sulfamethoxazole (10.7%). All 30 isolates investigated by WGS carried mecA, dfrG, and tet(38) genes. Other resistance genes detected were blaZ (83.3%), fosB (73.3%), tet(K) (60.0%), aacA-aphD (36.6%), aphA3 (33.3%), msr(A) (30.0%), mph(C) (30.0%), dfrS1 (3.3%), and sat4 (3.3%). Seven spa types (t091, t314, t657, t1476, t2331, t4690 and t12236), four known (dt9aw, dt10ao, dt10cj, and dt11a) and two novel (dt10dr and dt11dw) dru types, as well as five sequence types (ST8, ST121, ST152, ST772 and ST789) were found among the MRSA isolates. All ST121 isolates carried an SCCmec type IV cassette and were not dru-typeable. ST152 and ST121 were found only in specific sample categories within defined locations, while ST8 and ST772 were distributed across most sample categories and locations. Three SCCmec types, IVa, V and Vc, were identified. All MRSA isolates possessed virulence genes including aur, clpP, coa, fnbA, esaA, hly, hla, ica, isdA, srtB, sspA, and vWbp, among others. The toxic shock syndrome toxin gene (tst) was not detected in any isolate, whereas the Pantone–Valentine leukocidin genes lukF-PV/lukS-PV were present in all ST121, all ST772, and all but one ST152 isolates. Conclusion: The results of this study (i) showed that chicken meat is contaminated by MRSA and (ii) suggested that live bird markets may serve as focal points for the dissemination of MRSA within the community.