Recurrent skin and soft tissue infections (SSTIs) in three family members caused by methicillin-resistant Staphylococcus aureus (MRSA) with Panton-Valentine leukocidin (PVL) exotoxin.

Three family members attended their general practice and emergency department over a 3-month period with recurrent skin and soft tissue infections (SSTIs) such as paronychia, submandibular carbuncle and groin and gluteal abscess requiring surgical drainage. Only when two family members were concurrently admitted with abscesses requiring drainage under general anaesthetic was the definitive diagnosis reached. The wound swabs identified methicillin-resistant Staphylococcus aureus (MRSA) and subsequent identification of the exotoxin Panton-Valentine leukocidin (PVL). Following MRSA decolonisation therapy with mupirocin and octenidine, only one family member has had one recurrence of an SSTI with MRSA isolated from the wound. When patients present with a history of recurrent SSTIs or a family all have had similar presentations, the clinician should consider MRSA with PVL exotoxin infection. Then patients must be referred for confirmation to ensure management is effective for the SSTI and prescribe MRSA decolonisation therapy concurrently to reduce recurrence.

Dynamical analysis of methicillin-resistant Staphylococcus aureus infection in North Cyprus with optimal control: prevalence and awareness.

The number of Methicillin-resistant Staphylococcus aureus (MRSA) cases in communities and hospitals is on the rise worldwide. In this work, a nonlinear deterministic model for the dynamics of MRSA infection in society was developed to visualize the significance of awareness in interventions that could be applied in the prevention of transmission with and without optimal control. Positivity and uniqueness were verified for the proposed corruption model to identify the level of resolution of infection factors in society. Furthermore, how various parameters affect the reproductive number R 0 and sensitivity analysis of the proposed model was explored through mathematical techniques and figures. The global stability of model equilibria analysis was established by using Lyapunov functions with the first derivative test. A total of seven years of data gathered from a private hospital consisting of inpatients and outpatients of MRSA were used in this model for numerical simulations and for observing the dynamics of infection by using a non-standard finite difference (NSFD) scheme. When optimal control was applied as a second model, it was determined that increasing awareness of hand hygiene and wearing a mask were the key controlling measures to prevent the spread of community-acquired MRSA (CA-MRSA) and hospital-acquired MRSA (HA-MRSA). Lastly, it was concluded that both CA-MRSA and HA-MRSA cases are on the rise in the community, and increasing awareness concerning transmission is extremely significant in preventing further spread.

Genomic characterization of methicillin-resistant Staphylococcus aureus isolated from patients attending regional referral hospitals in Tanzania.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) colonization increases the risk of subsequent infection by MRSA strain complex interlinking between hospital and community-acquired MRSA which increases the chance of drug resistance and severity of the disease. OBJECTIVE: Genomic characterization of Staphylococcus aures strains isolated from patients attending regional referral hospitals in Tanzania. METHODOLOGY: A laboratory-based cross-sectional study using short read-based sequencing technology, (Nextseq550,Illumina, Inc. San diego, California, USA). The samples used were collected from patients attending selected regional referral hospitals in Tanzania under the SeqAfrica project. Sequences were analyzed using tools available in the center for genomic and epidemiology server, and visualization of the phylogenetic tree was performed in ITOL 6.0. SPSS 28.0 was used for statistical analysis. RESULTS: Among 103 sequences of S. aureus, 48.5% (50/103) carry the mecA gene for MRSA. High proportions of MRSA were observed among participants aged between 18 and 34 years (52.4%), in females (54.3%), and among outpatients (60.5%). The majority of observed MRSA carried plasmids rep5a (92.0%), rep16 (90.0%), rep7c (90.0%), rep15 (82.0%), rep19 (80.0%) and rep10 (72.0%). Among all plasmids observed rep5a, rep16, rep20, and repUS70 carried the blaZ gene, rep10 carried the erm(C) gene and rep7a carried the tet(K) gene. MLST and phylogeny analysis reveal high diversity among MRSA. Six different clones were observed circulating at selected regional hospitals and MRSA with ST8 was dominant. CONCLUSION: The study reveals a significant presence of MRSA in Staphylococcus aureus strains from Tanzanian regional hospitals, with nearly half carrying the mecA gene. MRSA is notably prevalent among young adults, females, and outpatients, showing high genetic diversity and dominance of ST8. Various plasmids carrying resistance genes indicate a complex resistance profile, highlighting the need for targeted interventions to manage MRSA infections in Tanzania.

Antimicrobial resistance profile of Staphylococcus aureus isolated from patients, healthcare workers, and the environment in a tertiary hospital in Addis Ababa, Ethiopia.

Staphylococcus aureus infection and colonization in patients may be transmitted to healthcare providers and the environment and subsequently cause healthcare-associated infections in other patients. Pathogenic S. aureus strains produce virulence factors, such as Panton-Valentine Leukocidin (PVL), that contribute to the severity of infections and aid in their spread. The emergence of antimicrobial resistance (AMR) is additional concern with respect to S. aureus infection. In this study, the virulence genes and antibiotic resistance profiles of S. aureus were characterized from patients' clinical isolates, healthcare workers' (HCWs') nasal colonization screenings, and the environment at a tertiary healthcare hospital in Addis Ababa, Ethiopia. A total of 365 samples were collected from September 2021 to September 2022: 73 patients' clinical specimens, 202 colonization screenings from HCWs, and 90 hospital environment's swabs. Fifty-one (25.2%) HCW and 10/90 (11.1%) environment S. aureus isolates were identified. Among the 134 isolates, 10 (7.5%) were methicillin-resistant S. aureus (MRSA). Three (4.1%), five (9.8%), and two (20.0%) of the MRSA isolates were identified from the patients, HCWs, and the environment, respectively. Overall, 118 (88.1%) were ampicillin and penicillin resistant; 70 (52.2%) were trimethoprim sulfamethoxazole resistant; and 28 (20.9%) were erythromycin resistant. S. aureus isolates from patients were more resistant to antibiotics than isolates from HCWs or the hospital environment (p<0.05). A total of 92/134 (68.6%) isolates possessed the lukfF-PV gene, which was identified in 62 (85.0%), 26 (51.0%), and 4 (40.0%) of the patient, HCWs, and the environment, respectively. The proportion of lukfF-PV gene containing S. aureus isolated from patient samples was statistically significant. Four (40.0%) of the MRSA isolates also had the lukfF-PV gene. The identification of highly AMR and virulence factors from patients, HCWs and the environment is concerning. Further studies are needed to identify potential transmission links and improve infection prevention and control.

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.

Multiplex fluorescence loop-mediated isothermal amplification with lateral flow assay for rapid simultaneous detection of mecA and nuc genes in methicillin-resistant Staphylococcus aureus.

BACKGROUND: Antibiotic-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), pose a significant threat to public health. Existing detection methods, like cultivation-based techniques, demand significant time and labor, while molecular diagnostic techniques, such as PCR, necessitate sophisticated instrumentation and skilled personnel. Although previous multiplex loop-mediated isothermal amplification assays based on fluorescent dyes (mfLAMP) offer simplicity and cost-effectiveness, they are prone to false-positive results. Therefore, developing a rapid and efficient multiplex assay for high-sensitivity MRSA is imperative to create a practical diagnostic tool for point-of-care testing. RESULTS: Here, we developed a mfLAMP combined with a lateral flow assay (mfLAMP-LFA) for the visual and simultaneous detection of the mecA (PBP2a-specific marker) and nuc (S. aureus-specific marker) genes in MRSA. We optimized mfLAMP-LFA using graphene oxide (GO)-based purification and specific DNA probes and evaluated its sensitivity, specificity, and stability. Utilizing GO to mitigate false-positive results by acting as a trap for free DNA probes, the mfLAMP-LFA method successfully identified mecAf and nucf-probes, exhibiting distinct red, green, and yellow fluorescence signals. The detection sensitivity of the developed mfLAMP-LFA method (1 CFU mL-1 in phosphate-buffered saline (PBS)) was comparable to other highly sensitive MRSA detection methods (1 CFU mL-1 in PBS). Furthermore, the method demonstrated specificity for MRSA, detecting it in irrigation water samples within the desired range and achieving reliable recovery rates from spiked samples. SIGNIFICANCE: This novel strategy is the first to incorporate GO into mfLAMP-LFA, enabling specific and sensitive MRSA detection and advancing rapid bacterial detection. This assay facilitates MRSA diagnostics, contributing to improved public health and food safety by delivering rapid, cost-effective point-of-care results. It enables the simultaneous detection of multiple bacteria, even in irrigation water samples artificially inoculated with MRSA, which contain aerobic bacteria at 2.7 × 102 CFU mL-1.

[Distribution and Drug Resistance Characteristics of Pathogenic Bacteria in the Elderly Population in China in 2021]. / 2021å¹´ä¸­å›½è€å¹´äººç¾¤æ„ŸæŸ“ç— åŽŸèŒåˆ†å¸ƒå’Œè€è¯æ€§ç‰¹å¾.

Objective: To study the distribution and drug resistance characteristics of pathogenic bacteria in the elderly population of China by collecting and analyzing the standardized case data on the pathogens of infections in elderly patients, and to facilitate the establishment of a standardized layered surveillance system for pathogenic bacteria in China. Methods: We collected the case data of elderly patients (≥65 years old) from 62 sentinel hospitals across the country in 2021. Then, we statistically analyzed the data by patient age, their geographical region, the distribution of pathogenic bacteria, and the drug resistance characteristics of main pathogens. Results: A total of 3468 cases from across the country were included in the study. The top three sources of patients were the intensive care unit (13.2%), the department of respiratory medicine (11.2%), and the department of general surgery (8.4%). The top three types of specimens were urine (25.5%), sputum (20.6%), and blood (18.7%). A total of 3468 strains of pathogens were isolated, among which, 78.9% were gram-negative bacteria and 21.1% were gram-positive bacteria. The top five types of bacteria were Escherichia coli (20.9%), Klebsiella pneumoniae (18.3%), Pseudomonas aeruginosa (11.2%), Staphylococcus aureus (9.0%), and Acinetobacter baumannii (7.0%). The isolation rates of common important drug-resistant bacteria were 38.0% for methicillin-resistant Staphylococcus aureus (MRSA), 68.7% for carbapenem-resistant Acinetobacter baumannii (CRAB), and 38.2% for carbapenem-resistant Pseudomonas aeruginosa (CRPA), 20.1% for carbapenem-resistant Klebsiella pneumoniae (CRKP), 5.2% for carbapenem-resistant Escherichia coli (CRECO), and 2.1% for vancomycin-resistant Enterococcus (VRE). There were differences in the isolation rates of CRAB and CRKP in clinical care in the elderly population in seven geographical regions of China (P<0.05). Klebsiella pneumoniae is the most important pathogen in the elderly population ≥85 years old, and the isolation rates of CRKP showed significant differences in different age groups (P<0.05). Conclusion: There are significant differences in the drug resistance of pathogenic bacteria in the elderly populations of different regions and age groups in China. Therefore, monitoring the distribution and drug resistance of pathogenic bacteria in the elderly population and formulating targeted treatment plans according to the characteristics of the specific regions and age groups are of great significance to the improvement in the treatment outcomes and prognosis of the elderly population.

Pathogenomic profile and clonal diversity of potential zoonotic MRSA-CC7-ST789-t091-SCCmecV from human skin and soft tissue infections.

The whole genome sequence (WGS) of prevalent MRSA strains harboring mecA gene obtained from skin and soft tissue infections (SSTIs) in Nigerian hospitals were profiled for pathogenomic structure and evaluated for clonal diversity. The two MRSA strains identified among 66 isolated multi-drug resistant S. aureus from a collection of 256 clinical samples were phenotyped for antibiotic resistance and genotyped for mecA, SCCmec, and spa types. The mecA positive MRSA was analysed using whole-genome sequencing for resistomes, virulomes, phylogenomic profiles and clonal diversity. The identified MRSA-CC7-ST789-t091-SCCmecV strains from a female child (aged 1 year) with severe otorrhea and an adult male (aged 23) with purulent wound abscess showed high-level resistance to streptomycin, vancomycin, kanamycin, sulfamethoxazole and ciprofloxacin. Both strains harbored abundant resistomes, inherent plasmids, chromosomal replicons and typical seven housekeeping genes (arc3, aroE4, glpF1, gmk4, pta4, tpi6, yqiL3). The most abundant putative virulomes were pathogenesis-associated proteins (included hemolysin gamma, leucocidins, proteases, staphylococcal superantigen/enterotoxin-like genes (Set/Ssl), capsule- and biofilm-associated genes, and hyaluronate lyase). Comparative phylogenomic analysis revealed the relatedness of the two clonal strains with prevalent MRSA-CC7 pathotypes observed in Italy (2013 and 2014), Denmark (2014), Thailand (2015 and 2016), USA (2018), and Nigeria (2016 and 2020); and share high genetic similarities with livestock strains from cow milk and cattle. Identified MRSA-CC7-ST789-t091-SCCmecV pathotypes implicated in SSTIs from Nigeria harboring repertoires of antibiotic resistance and virulence genes, and genetic relatedness with livestock strains; show the possibility of gene transfer between animal and human. Adequate hospital MRSA infection control and geno-epidemiological surveillance for animal and human transfer is required.

Vaginal colonization with virulent and methicillin resistant Staphylococcus aureus among Ugandan women in Labour.

BACKGROUND: Staphylococcus aureus (S. aureus) often colonizes the human skin, upper respiratory and genital tracts. In the female genital tract, it can be passed on to the newborn during vaginal delivery leading to either ordinary colonization, or neonatal infections notably umbilical stump sepsis, scalded skin syndrome, arthritis, or bacteraemia/sepsis. These infections are mediated by staphylococcal virulence factors such as (i) Staphylococcal Enterotoxins A, B, C, D, and E encoded by the sea, seb, sec, sed, see genes, (ii) Exfoliative Toxins A and B encoded by the eta and etb genes, (iii) Toxic Shock Syndrome Toxin 1 (TSST-1) encoded by the tst gene, (iv) Panton-Valentine Leukocidin (PVL) encoded by the pvl gene, and (v) Hemolysins alpha and delta encoded by the hla and hld genes, respectively. We determined the prevalence of S. aureus possessing one or more virulence factor genes and of methicillin resistant Staphylococcus aureus (MRSA) in this population. METHODS: This was a cross-sectional study, which used 85 S. aureus isolates from the Chlorohexidine (CHX) clinical trial study in Uganda. The isolates had been obtained by culturing vaginal swabs (VS) from 1472 women in labour, frozen at minus 80oC, then thawed, sub-cultured, and tested for the selected virulence genes sea, seb, sec, sed, see eta, etb, tst, pvl, hla and hld, and for the methicillin resistance determining gene (mecA). Data were analyzed using SPSS version 20. RESULTS: Of the 85 S. aureus isolates 13 (15.3%) were positive for one or more virulence factor genes, as follows: pvl 9/85 (10.6%), hld 5/85 (5.9%), sea 1/85 (1.2%) and seb genes 1/85 (1.2%). The other virulence genes (sec, sed, see, eta, etb, hla and tst) were not detected in any of the isolates. MRSA was detected in 55.3% (47/85) of the isolates, but only two of these carried the pvl virulence gene. CONCLUSION: This study demonstrated that 15% of the S. aureus colonizing the female lower genital tract of mothers in labour in central Uganda carried one or more virulence genes, mostly pvl, indicating potential for newborn infection with S. aureus acquired in the maternal birth canal. More than half of the isolates were MRSA.

Panton-Valentine leucocidin gene in methicillin resistant Staphylococcus aureus isolated from tertiary care hospital in Nepal.

INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) expresses the Panton-Valentine leukocidin (PVL) virulence gene, which is associated with community and hospital-acquired severe MRSA infections. The objective of this study was to determine the prevalence and antibiotic susceptibility profile with a focus on the presence of the PVL gene among MRSA isolates in healthcare settings. METHODOLOGY: A total of 1,207 clinical specimens and 304 hospital environment swabs were collected in a tertiary care hospital in Nepal, and investigated following basic microbiological techniques. S. aureus was confirmed with the coagulase test. An antibiotic susceptibility test (AST) was performed by the Kirby-Bauer method and screening for MRSA was carried out by the cefoxitin disc diffusion method guided by the Clinical and Laboratory Standards Institute (CLSI), 2020. DNA was extracted and used in a polymerase chain reaction (PCR) to detect mecA and PVL genes. RESULTS: Of the 1,511 samples, 45 (2.9%) S. aureus (23 clinical and 22 environmental) were isolated. Among them, 69.6% (16/23) and 27.3% (6/22) were MRSA in clinical and environmental isolates, respectively. Twelve (52.2%) clinical isolates and seven (31.8%) environmental isolates were multidrug resistant. The majority of isolates were susceptible to vancomycin and linezolid. The PVL gene was detected in 18.2% (n = 4/22) of the MRSA isolates, of which three were from clinical sources and one was from an environmental swab. CONCLUSIONS: The prevalence of MRSA, and PVL-producing S. aureus were higher in the hospital setting. Hence, immediate and urgent implementation of infection control and sanitation measures are needed in the hospital.

Genomic Insights of a Methicillin-Resistant Biofilm-Producing Staphylococcus aureus Strain Isolated From Food Handlers.

Methicillin-resistant Staphylococcus aureus (MRSA) is an important zoonotic pathogen associated with a wide range of infections in humans and animals. Thus, the emergence of MRSA clones poses an important threat to human and animal health. This study is aimed at elucidating the genomics insights of a strong biofilm-producing and multidrug-resistant (MDR) S. aureus MTR_BAU_H1 strain through whole-genome sequencing (WGS). The S. aureus MTR_BAU_H1 strain was isolated from food handlers' hand swabs in Bangladesh and phenotypically assessed for antimicrobial susceptibility and biofilm production assays. The isolate was further undergone to high throughput WGS and analysed using different bioinformatics tools to elucidate the genetic diversity, molecular epidemiology, sequence type (ST), antimicrobial resistance, and virulence gene distribution. Phenotypic analyses revealed that the S. aureus MTR_BAU_H1 strain is a strong biofilm-former and carries both antimicrobial resistance (e.g., methicillin resistance; mecA, beta-lactam resistance; blaZ and tetracycline resistance; tetC) and virulence (e.g., sea, tsst, and PVL) genes. The genome of the S. aureus MTR_BAU_H1 belonged to ST1930 that possessed three plasmid replicons (e.g., rep16, rep7c, and rep19), seven prophages, and two clustered regularly interspaced short palindromic repeat (CRISPR) arrays of varying sizes. Phylogenetic analysis showed a close evolutionary relationship between the MTR_BAU_H1 genome and other MRSA clones of diverse hosts and demographics. The MTR_BAU_H1 genome harbours 42 antimicrobial resistance genes (ARGs), 128 virulence genes, and 273 SEED subsystems coding for the metabolism of amino acids, carbohydrates, proteins, cofactors, vitamins, minerals, and lipids. This is the first-ever WGS-based study of a strong biofilm-producing and MDR S. aureus strain isolated from human hand swabs in Bangladesh that unveils new information on the resistomes (ARGs and correlated mechanisms) and virulence potentials that might be linked to staphylococcal pathogenesis in both humans and animals.

Seizing the Hidden Assassin: Current Detection Strategies for Staphylococcus aureus and Methicillin-Resistant S. aureus.

Staphylococcus aureus (S. aureus) is a kind of pathogenic bacteria which can lead to food poisoning, hospital, and community infections. S. aureus and methicillin-resistant S. aureus (MRSA) have become headaches for public health worldwide. Therefore, strengthening the detection of S. aureus and MRSA is a critical step to prevent and control its spread and infection. This review summarized multiple detection methods (electrochemical, optical, and other biosensors) for sensitive and efficient detection of nonresistant and resistant S. aureus. First, we have introduced the principle and methods of detection platform for S. aureus and MRSA. We also contrasted various detection strategies. Finally, the current situation and prospect of S. aureus and MRSA detection in the future are explored in depth, and its development direction of detection methods is also predicted. In this review, we found that although biosensors have shown tremendous brilliance in the field of monitoring, they are currently in the experimental stage. It can be certain that we are very close to entering the commercialization stage. The point-of care testing available to nonprofessionals will become a new direction. We firmly believe that the monitoring system will be more perfect and stable and public life will be healthier and safer.

Prevalence and types of methicillin-resistant Staphylococcus aureus (MRSA) in meat and meat products from retail outlets and in samples of animal origin collected in farms, slaughterhouses and meat processing facilities. A review.

Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent cause of nosocomial and community infections, in some cases severe and difficult to treat. In addition, there are strains of MRSA that are specifically associated with food-producing animals. For this reason, in recent years special attention has been paid to the role played by foodstuffs of animal origin in infections by this microorganism. With the aim of gaining knowledge on the prevalence and types of MRSA in meat and meat products, a review was undertaken of work published on this topic since 2001, a total of 259 publications, 185 relating to meat samples from retail outlets and 74 to samples of animal origin collected in farms, slaughterhouses and meat processing facilities. Strains of MRSA were detected in 84.3% reports (156 out of 185) from retail outlets and 86.5% reports (64 out of 74) from farms, slaughterhouses and meat processing facilities, although in most of the research this microorganism was detected in under 20% of samples from retail outlets, and under 10% in those from farms, slaughterhouses and meat processing facilities. The meat and meat products most often contaminated with MRSA were pork and chicken. In addition to the mecA gene, it is crucial to take into consideration the mecB and mecC genes, so as to avoid misidentification of strains as MSSA (methicillin-susceptible Staphylococcus aureus). The great variety of methods used for the determination of MRSA highlights the need to develop a standardized protocol for the study of this microorganism in foods.

Molecular characterization of Methicillin-resistant Staphylococcus aureus isolated in ready-to-eat food sold in supermarkets in Bobo-Dioulasso: case of charcuterie products.

BACKGROUND: Staphylococcus aureus (S. aureus) is one of the most widespread bacterial pathogens in animals and humans, and its role as an important causative agent of food poisoning is well-documented. The aim of this study was to highlight and characterize the resistance patterns of methicillin-resistant S. aureus (MRSA) in charcuterie products sold in selected supermarkets (SM) in Bobo-Dioulasso, Burkina Faso. METHODS: In this study, 72 samples including ham (n = 19), merguez (n = 22), sausage (n = 15) and minced meat (n = 16) were collected from 3 supermarkets. Standard microbiology methods were utilised to characterise S. aureus isolates. Phenotypic resistance patterns were investigated using the disk diffusion method on Mueller-Hinton agar. Genotypic testing using polymerase chain reaction (PCR) was performed on the isolates to detect the 16S-23S gene. Using specific primers, the following genes PVL, TSST-1, mecA, gyrA, gyrB, qnrA, intI1 and aac(6')-Ib-cr were identified from purified DNA by PCR. RESULTS: Among the 72 ready-to-eat food samples, S. aureus was present in 51, (70.83%). The yield was highest in both the ham and merguez food products, 15/51 (29.41%) each, followed by minced meat 12/51 (23.53%) and sausage 9/51 (17.65%). A total of 35 isolates (68.63%) were confirmed as S. aureus after molecular characterization using 16-23 S primers with 05 (14.29%) strains identified as MRSA. All of the MRSA and majority of the methicillin-sensitive S.aureus (MSSA) isolates were resistant to penicillin G, ampicillin, tetracycline and erythromycin, whereas one isolate from minced meat was found in SM3-harbouring PVL, TSST-1, mecA, gyrA, gyrB and Int1 genes. CONCLUSIONS: Our study revealed a high prevalence of S. aureus in chacuterie products in Bobo-Dioulasso with antimicrobial profiles that show resistance to most antibiotics. These findings should inform and augment efforts to raise awareness among local supermarket owners on adequate food manufacturing practices as well as promoting food safety and hygiene.

Ruthenibacterium lactatiformans isolated from a human blood culture: a first report.

BACKGROUND: Ruthenibacterium lactatiformans, a Gram-stain-negative, rod-shaped, obligate anaerobic bacterium of the Oscillospiraceae family, has not been previously reported in human infections. This study reports the first case of bacteraemia and potential vertebral osteomyelitis caused by Ruthenibacterium lactatiformans. CASE PRESENTATION: An 82-year-old man with a history of diabetes, chronic renal failure, and prior spinal surgery for spondylolisthesis and spinal stenosis presented with fever and lower back pain. Magnetic resonance imaging revealed multiple vertebral osteomyelitis lesions. Initial blood cultures identified methicillin-resistant Staphylococcus aureus (MRSA), which prompted vancomycin treatment. However, repeated blood cultures not only confirmed persistent MRSA, but also detected Gram-negative bacilli (GNB). Despite surgical removal of the spinal hardware and antimicrobial therapy, the patient's osteomyelitis worsened, necessitating transfer for further management. Subsequent analysis using 16S rRNA gene sequencing identified the GNB as Ruthenibacterium lactatiformans. CONCLUSIONS: This is the first documented instance of human infection with Ruthenibacterium lactatiformans, signifying its pathogenic potential in vertebral osteomyelitis. The involvement of anaerobic bacteria and the possibility of polymicrobial infections complicate the diagnosis and treatment of vertebral osteomyelitis. This report underscores the need for caution when identifying the causative organism and selecting an appropriate treatment.

Case Report: Non-ischemic Papillary Muscle Rupture due to MRSA Myocarditis with Concurrent Thromboembolic Myocardial Infarction Secondary to Infective Endocarditis.

Non-ischemic papillary muscle rupture (PMR) is rare. PMR caused by myocarditis in the presence of concurrent infective endocarditis (IE) and myocardial infarction (MI) has not been described. We report a 46-year-old male with recurrent MRSA bacteremia who presented in septic shock and suffered cardiac arrest. Echocardiography revealed acute mitral valve regurgitation resulting from posteromedial PMR. An intra-aortic balloon pump was implanted. Angiography revealed thrombotic occlusion of a small distal left circumflex artery. Emergent mitral valve replacement surgery was performed. MRSA myocarditis and IE were diagnosed by tissue cultures. Coexistence of myocarditis, IE, and MI poses a challenge in determining etiology.

Biofilm-producing ability of methicillin-resistant Staphylococcus aureus clinically isolated in China.

BACKGROUND: Staphylococcus aureus, a commensal bacterium, colonizes the skin and mucous membranes of approximately 30% of the human population. Apart from conventional resistance mechanisms, one of the pathogenic features of S. aureus is its ability to survive in a biofilm state on both biotic and abiotic surfaces. Due to this characteristic, S. aureus is a major cause of human infections, with Methicillin-Resistant Staphylococcus aureus (MRSA) being a significant contributor to both community-acquired and hospital-acquired infections. RESULTS: Analyzing non-repetitive clinical isolates of MRSA collected from seven provinces and cities in China between 2014 and 2020, it was observed that 53.2% of the MRSA isolates exhibited varying degrees of ability to produce biofilm. The biofilm positivity rate was notably high in MRSA isolates from Guangdong, Jiangxi, and Hubei. The predominant MRSA strains collected in this study were of sequence types ST59, ST5, and ST239, with the biofilm-producing capability mainly distributed among moderate and weak biofilm producers within these ST types. Notably, certain sequence types, such as ST88, exhibited a high prevalence of strong biofilm-producing strains. The study found that SCCmec IV was the predominant type among biofilm-positive MRSA, followed by SCCmec II. Comparing strains with weak and strong biofilm production capabilities, the positive rates of the sdrD and sdrE were higher in strong biofilm producers. The genetic determinants ebp, icaA, icaB, icaC, icaD, icaR, and sdrE were associated with strong biofilm production in MRSA. Additionally, biofilm-negative MRSA isolates showed higher sensitivity rates to cefalotin (94.8%), daptomycin (94.5%), mupirocin (86.5%), teicoplanin (94.5%), fusidic acid (81.0%), and dalbavancin (94.5%) compared to biofilm-positive MRSA isolates. The biofilm positivity rate was consistently above 50% in all collected specimen types. CONCLUSIONS: MRSA strains with biofilm production capability warrant increased vigilance.

Time-calibrated phylogenetic and chromosomal mobilome analyses of Staphylococcus aureus CC398 reveal geographical and host-related evolution.

An international collection of Staphylococcus aureus of clonal complex (CC) 398 from diverse hosts spanning all continents and a 30 year-period is studied based on whole-genome sequencing (WGS) data. The collection consists of publicly available genomic data from 2994 strains and 134 recently sequenced Swiss methicillin-resistant S. aureus (MRSA) CC398 strains. A time-calibrated phylogeny reveals the presence of distinct phylogroups present in Asia, North and South America and Europe. European MRSA diverged from methicillin-susceptible S. aureus (MSSA) at the beginning of the 1950s. Two major European phylogroups (EP4 and EP5), which diverged approximately 1974, are the main drivers of MRSA CC398 spread in Europe. Within EP5, an emergent MRSA lineage spreading among the European horse population (EP5-Leq) diverged approximately 1996 from the pig lineage (EP5-Lpg), and also contains human-related strains. EP5-Leq is characterized by staphylococcal cassette chromosome mec (SCCmec) IVa and spa type t011 (CC398-IVa-t011), and EP5-Lpg by CC398-SCCmecVc-t011. The lineage-specific antibiotic resistance and virulence gene patterns are mostly mediated by the acquisition of mobile genetic elements like SCCmec, S. aureus Genomic Islands (SaGIs), prophages and transposons. Different combinations of virulence factors are present on S. aureus pathogenicity islands (SaPIs), and novel antimicrobial resistance gene containing elements are associated with certain lineages expanding in Europe. This WGS-based analysis reveals the actual evolutionary trajectory and epidemiological trend of the international MRSA CC398 population considering host, temporal, geographical and molecular factors. It provides a baseline for global WGS-based One-Health studies of adaptive evolution of MRSA CC398 as well as for local outbreak investigations.

Impact of terminal cleaning in rooms previously occupied by patients with healthcare-associated infections.

Healthcare associated infections (HAIs) are costly but preventable. A limited understanding of the effects of environmental cleaning on the riskiest HAI associated pathogens is a current challenge in HAI prevention. This project aimed to quantify the effects of terminal hospital cleaning practices on HAI pathogens via environmental sampling in three hospitals located throughout the United States. Surfaces were swabbed from 36 occupied patient rooms with a laboratory-confirmed, hospital- or community-acquired infection of at least one of the four pathogens of interest (i.e., Acinetobacter baumannii (A. baumannii), methicillin resistant Staphylococcus aureus (MRSA), vancomycin resistant Enterococcus faecalis/faecium (VRE), and Clostridioides difficile (C. difficile)). Six nonporous, high touch surfaces (i.e., chair handrail, bed handrail, nurse call button, desk surface, bathroom counter near the sink, and a grab bar near the toilet) were sampled in each room for Adenosine Triphosphate (ATP) and the four pathogens of interest before and after terminal cleaning. The four pathogens of interest were detected on surfaces before and after terminal cleaning, but their levels were generally reduced. Overall, C. difficile was confirmed on the desk (n = 2), while MRSA (n = 24) and VRE (n = 25) were confirmed on all surface types before terminal cleaning. After cleaning, only MRSA (n = 6) on bed handrail, chair handrail, and nurse call button and VRE (n = 5) on bathroom sink, bed handrail, nurse call button, toilet grab bar, and C. difficile (n = 1) were confirmed. At 2 of the 3 hospitals, pathogens were generally reduced by >99% during terminal cleaning. One hospital showed that VRE increased after terminal cleaning, MRSA was reduced by 73% on the nurse call button, and VRE was reduced by only 50% on the bathroom sink. ATP detections did not correlate with any pathogen concentration. This study highlights the importance of terminal cleaning and indicates room for improvement in cleaning practices to reduce surface contamination throughout hospital rooms.