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Understanding the epidemiology of mecA-positive Staphylococcus pseudintermedius strains, including those that are oxacillin-susceptible but potentially inducible to resistance, is crucial for developing effective treatment strategies and mitigating public health risks. This study characterized 87 mecA-positive S. pseudintermedius isolates obtained from skin lesions and nasal orifices of 46 dogs with pyoderma enrolled at a referral hospital in Thailand between 2019 and 2020. All isolates underwent antibiogram profiling, SCCmec typing, and pulsed-field gel electrophoresis (PFGE) for phenotypic and genetic analysis. Among the 87 isolates, 33 isolates (37.9%) recovered from 15 dogs were oxacillin-resistant (OR-MRSP), while 54 isolates (62.1%) from 31 dogs were oxacillin-susceptible (OS-MRSP). All OR-MRSP isolates exhibited multidrug resistance (MDR), and 44% of the OS-MRSP isolates also showed MDR. SCCmec typing revealed type V as predominant among OR-MRSP isolates (69.7%), while many oxacillin-susceptible isolates (70.4%) were non-typeable. The OR-MRSP isolates from the same dog showed consistent antibiogram and SCCmec types, while OS-MRSP isolates displayed both identical and diverse patterns. No dominant pulsotypes were observed among the OR-MRSP or OS-MRSP strains. Genetic diversity was also noted among the isolates within the same dogs and among the others, highlighting the complexity of S. pseudintermedius colonization and infection dynamics in pyoderma-affected dogs.

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BACKGROUND: The use of matrix-assisted laser desorption/ionization-time-of-flight mass spectra (MALDI-TOF MS) with machine learning (ML) has been explored for predicting antimicrobial resistance. This study evaluates the effectiveness of MALDI-TOF MS paired with various ML classifiers and establishes optimal models for predicting antimicrobial resistance and mecA gene existence among Staphylococcus aureus. MATERIALS AND METHODS: The antimicrobial resistance against tier 1 antibiotics and MALDI-TOF MS of S. aureus were analyzed using data from the Database of Resistance against Antimicrobials with MALDI-TOF Mass Spectrometry (DRIAMS) and one medical center (CS database). Five ML classifiers were used to analyze performance metrics. The Shapley value quantified the predictive contribution of individual feature. RESULTS: The LightGBM demonstrated superior performance in predicting antimicrobial resistance for most tier 1 antibiotics among oxacillin-resistant S. aureus (ORSA) than all and oxacillin-susceptible S. aureus (OSSA) in both databases. In DRIAMS, MLP encompassed excellent predictive performance, expressed as accuracy/AUROC/AUPR, for clindamycin (0.74/0.81/0.90), tetracycline (0.86/0.87/0.94), and trimethoprim-sulfamethoxazole (0.95/0.72/0.97). In CS database, Ada and LightGBM retained excellent performance for erythromycin (0.97/0.92/0.86) and tetracycline (0.68/0.79/0.86), respectively. Mass-to-charge ratio (m/z) features of 2,411-2,414 and 2,429-2,432 correlated with clindamycin resistance, while 5,033-5,036 was linked to erythromycin resistance in DRIAMS. In CS database, overlapping features of 2,423-2,426, 4,496-4,499, and 3,764-3,767 simultaneously predicted mecA existence and oxacillin resistance. CONCLUSION: The predictive performance of antimicrobial resistance against S. aureus using MALDI-TOF MS depends on database characteristics and ML algorithm selected. Specific and overlapping MS features are excellent predictive markers for mecA and specific antimicrobial resistance.

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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.

Asunto(s)

Staphylococcus aureus Resistente a Meticilina , Filogenia , Infecciones de los Tejidos Blandos , Humanos , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Animales , Infecciones de los Tejidos Blandos/microbiología , Infecciones de los Tejidos Blandos/epidemiología , Femenino , Masculino , Secuenciación Completa del Genoma , Lactante , Adulto Joven , Antibacterianos/farmacología , Nigeria , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/epidemiología , Infecciones Cutáneas Estafilocócicas/microbiología , Infecciones Cutáneas Estafilocócicas/epidemiología , Pruebas de Sensibilidad Microbiana , Farmacorresistencia Bacteriana Múltiple/genética

RESUMEN

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.

Asunto(s)

Antibacterianos , Toxinas Bacterianas , Exotoxinas , Leucocidinas , Staphylococcus aureus Resistente a Meticilina , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas , Centros de Atención Terciaria , Leucocidinas/genética , Exotoxinas/genética , Nepal/epidemiología , Humanos , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Toxinas Bacterianas/genética , Centros de Atención Terciaria/estadística & datos numéricos , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/epidemiología , Antibacterianos/farmacología , Prevalencia , Femenino , Adulto , Masculino , Infección Hospitalaria/microbiología , Infección Hospitalaria/epidemiología , Persona de Mediana Edad , Adulto Joven , Adolescente , Proteínas Bacterianas/genética

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Recently emancipated from the Staphylococcus genus due to genomic differences, Mammaliicoccus sciuri, previously classified as an occasional pathogen, emerges as a significant player in the landscape of resistance gene dissemination among Staphylococcaceae. Despite its classification, its role remained enigmatic. In this study, we delved into the genomic repertoire of M. sciuri to unravel its contribution to resistance and virulence gene transfer in the context of One Health. Through comprehensive analysis of publicly available genomes, we unveiled a diverse pan-immune system adept at defending against exogenous genetic elements, yet concurrently fostering horizontal gene transfer (HGT). Specifically, exploration of CRISPR-Cas systems, with spacer sequences as molecular signatures, elucidated a global dissemination pattern spanning environmental, animal, and human hosts. Notably, we identified the integration of CRISPR-Cas systems within SCCmecs (Staphylococcal Cassette Chromosome mec), harboring key genes associated with pathogenicity and resistance, especially the methicillin resistance gene mecA, suggesting a strategic adaptation to outcompete other mobile genetic elements. Our findings underscored M. sciuri's active engagement in HGT dynamics and evolutionary trajectories within Staphylococcaceae, emphasizing its central role in shaping microbial communities and highlighting the significance of understanding its implications in the One Health framework, an interdisciplinary approach that recognizes the interconnectedness of human, animal, and environmental health to address global health challenges.

RESUMEN

Close contact between cats and humans increases the risk of transmission of zoonotic pathogens, through bites and scratches due to the complexity of microorganisms in the oral and nail microbiotas of felines. This study investigated the presence of bacteria and fungi in the oral cavity and claws of 100 apparently healthy cats using conventional and selective microbiological culture media, and next-generation sequencing (NGS) and mass spectrometry (MALDI-TOF MS). Furthermore, antimicrobial susceptibility testing of bacteria isolates was performed by disc diffusion method. In total, 671 bacteria and 33 yeasts were identified by MALDI-TOF MS. Neisseria animaloris (10.8 %), Staphylococcus felis (8.5 %), and Pasteurella multocida (7 %) were the most prevalent bacteria in oral cavity samples (n = 343), while the most common yeast (n = 19) was Candida albicans (68.4 %). Staphylococcus pettenkoferi (13.4 %), Staphylococcus felis (6.4 %), and Staphylococcus simulans (5.8 %) were the prevalent bacteria identified in the claw samples (n = 328), while Rhodotorula mucilaginosa (57.2 %) was the most common yeast (n = 14). NGS predominantly identified the genera Moraxella, Neisseria, Pasteurella, and Fusobacterium in oral cavity samples, whereas enterobacteria and staphylococci were prevalent in nail bed samples. In addition, the genera Capnocytophaga and Bartonella were identified, which have been described in serious human infections secondary to feline aggressions. Levofloxacin, marbofloxacin, and amoxicillin/clavulanic acid were the most effective drugs against the main groups of bacteria identified. Multidrug resistance was observed in 17 % of the bacterial isolates. Furthermore, three staphylococci harboring the methicillin resistance gene mecA were identified. We highlight the complexity of microorganisms inhabiting the oral/claw microbiotas of cats, the high resistance rate of the isolates to conventional antimicrobial agents, and the zoonotic risk of aggressions caused by bites and scratches from domestic cats.

Asunto(s)

Bacterias , Secuenciación de Nucleótidos de Alto Rendimiento , Boca , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Gatos , Animales , Boca/microbiología , Bacterias/aislamiento & purificación , Bacterias/clasificación , Bacterias/genética , Bacterias/efectos de los fármacos , Hongos/aislamiento & purificación , Hongos/genética , Hongos/clasificación , Hongos/efectos de los fármacos , Antibacterianos/farmacología , Pruebas de Sensibilidad Microbiana , Enfermedades de los Gatos/microbiología

RESUMEN

Chlamydia trachomatis (Ct) is the most common sexually transmitted bacterial infection worldwide, potentially leading to severe pathologies including pelvic inflammatory disease, ectopic pregnancy, and tubal infertility if left untreated. Current strategies, including screening and antibiotics, have limited effectiveness due to high rates of asymptomatic cases and logistical challenges. A multiepitope prophylactic vaccine could afford long-term protection against infection. Immunoinformatic analyses were employed to design a multiepitope Chlamydia vaccine antigen. B- and T-cell epitopes from five highly conserved and immunogenic Ct antigens were predicted and selected for the vaccine design. The final construct, adjuvanted with cholera toxin A1 subunit (CTA1), was further screened for immunogenicity. CTA1-MECA (multiepitope Chlamydia trachomatis antigen) was identified as antigenic and nonallergenic. A tertiary structure was predicted, refined, and validated as a good quality model. Molecular docking exhibited strong interactions between the vaccine and toll-like receptor 4 (TLR4). Additionally, immune responses consistent with protection including IFN-γ, IgG + IgM antibodies, and T- and B-cell responses were predicted following vaccination in an immune simulation. Expression of the construct in an Escherichia coli expression vector proved efficient. To further validate the vaccine efficacy, we assessed its immunogenicity in mice. Immunization with CTA1-MECA elicited high levels of Chlamydia-specific antibodies in mucosal and systemic compartments.

Asunto(s)

Anticuerpos Antibacterianos , Vacunas Bacterianas , Infecciones por Chlamydia , Chlamydia trachomatis , Epítopos de Linfocito B , Epítopos de Linfocito T , Simulación del Acoplamiento Molecular , Vacunas Bacterianas/inmunología , Vacunas Bacterianas/genética , Infecciones por Chlamydia/prevención & control , Infecciones por Chlamydia/inmunología , Animales , Chlamydia trachomatis/inmunología , Epítopos de Linfocito T/inmunología , Ratones , Anticuerpos Antibacterianos/inmunología , Anticuerpos Antibacterianos/sangre , Epítopos de Linfocito B/inmunología , Epítopos de Linfocito B/genética , Femenino , Antígenos Bacterianos/inmunología , Antígenos Bacterianos/química , Antígenos Bacterianos/genética , Simulación por Computador , Epítopos/inmunología , Humanos , Receptor Toll-Like 4/inmunología , Receptor Toll-Like 4/metabolismo , Toxina del Cólera/inmunología , Toxina del Cólera/genética , Modelos Animales de Enfermedad

RESUMEN

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) poses a great health threat to humans. Looking for compounds that could reduce the resistance of S. aureus towards methicillin is an effective way to alleviate the antimicrobial resistance crisis. METHODS AND RESULTS: Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), Time-killing growth curve, staphyloxanthin and penicillin-binding protein 2a (PBP2a) were detected. A quantitative polymerase chain reaction was used to measure the effect of BBH on the gene transcription profiles of MRSA. The MIC of MRSA-ST59-t437 towards oxacillin was 8 µg/ml, and MBC was 128 µg/ml. After adding a sub-inhibitory concentration of BBH, the MIC and MBC of MRSA-ST59-t478 towards oxacillin went down to 0.125 and 32 µg/ml respectively. The amount of PBP2a and staphyloxanthin were reduced after treatment with BBH. Moreover, the transcription levels of sarA, mecA and fni genes were downregulated. CONCLUSIONS: It is for the first time reported that BBH could inhibit staphyloxanthin synthesis by inhibiting fni gene. Moreover, fni might be the target gene of sarA, and there might be another regulatory pathway to inhibit staphyloxanthin biosynthesis. BBH could effectively reduce the methicillin resistance of MRSA-ST59-t437 by downregulating fni, sarA and mecA genes.

Asunto(s)

Antibacterianos , Proteínas Bacterianas , Berberina , Staphylococcus aureus Resistente a Meticilina , Pruebas de Sensibilidad Microbiana , Xantófilas , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/genética , Xantófilas/farmacología , Berberina/farmacología , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Antibacterianos/farmacología , Proteínas de Unión a las Penicilinas/genética , Proteínas de Unión a las Penicilinas/metabolismo , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Oxacilina/farmacología

RESUMEN

Staphylococcus spp. are growing pathogens in humans and companion animals. The emergence of multidrug-resistant bacterial infections, such as methicillin-resistant Staphylococcus-associated infections, due to zoonotic transmission, is a major public health concern. Domestic animals, such as dogs and cats, are possible reservoirs of multi-resistant bacterial species, which makes it relevant to monitor them due to their proximity to humans. However, there is a lack of information on the real scenario in Europe, especially in Portugal, particularly for animal infections caused by Staphylococcus spp. Therefore, this study aimed to investigate the antimicrobial resistance profile of Staphylococcus spp. isolated from cats and dogs diagnosed with infection in Northern Portugal. During 2021-2023, 96 Staphylococcus isolates from dogs and cats with symptoms of bacterial infection, including animals being treated in veterinary clinics/hospitals and cadavers submitted for necropsy at INIAV were included in the study collection. Of the 96 isolates, 63 were from dogs and 33 were Staphylococcus spp. from cats, most of which were isolated from ear (57% and 18%, respectively), skin (19 % and 27 %, respectively) and respiratory tract infections (6 % and 27 %, respectively). Among all the isolates, 12 different Staphylococcus spp. were identified, with Staphylococcus pseudintermedius being the most identified (61 % from dogs and 30 % from cats). It is noteworthy that 36 % of the isolates were multi-drug resistant and 25 % of the isolates showed a methicillin-resistant phenotype, with the mecA gene having been identified in all these isolates. This study highlights a high occurrence of multidrug-resistant Staphylococcus spp. in companion animals in Northern Portugal. This underlines the potential for cats and dogs to act as reservoirs of antimicrobial resistance, that can be transmitted to humans, posing a serious threat to public health.

Asunto(s)

Antibacterianos , Enfermedades de los Gatos , Enfermedades de los Perros , Mascotas , Infecciones Estafilocócicas , Staphylococcus , Animales , Gatos , Perros , Portugal/epidemiología , Staphylococcus/efectos de los fármacos , Staphylococcus/genética , Staphylococcus/aislamiento & purificación , Enfermedades de los Gatos/microbiología , Enfermedades de los Gatos/epidemiología , Infecciones Estafilocócicas/veterinaria , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/epidemiología , Enfermedades de los Perros/microbiología , Enfermedades de los Perros/epidemiología , Antibacterianos/farmacología , Mascotas/microbiología , Pruebas de Sensibilidad Microbiana/veterinaria , Farmacorresistencia Bacteriana Múltiple , Farmacorresistencia Bacteriana

RESUMEN

Pet food have been considered as possible vehicles of bacterial pathogens. The sudden boom of the pet food industry due to the worldwide increase in companion animal ownership calls for pet food investigations. Herein, this study aimed to determine the frequency, antimicrobial susceptibility profile, and molecular characteristics of coagulase-negative staphylococci (CoNS) in different pet food brands in Brazil. Eighty-six pet food packages were screened for CoNS. All isolates were identified at species level by MALDI-TOF MS and species-specific PCR. Antimicrobial susceptibility testing was performed by disc diffusion and broth microdilution (vancomycin and teicoplanin only) methods. The D-test was used to screen for inducible clindamycin phenotype (MLS-B). SCCmec typing and detection of mecA, vanA, vanB, and virulence-encoding genes were done by PCR. A total of 16 (18.6 %) CoNS isolates were recovered from pet food samples. Isolates were generally multidrug-resistant (MDR). All isolates were completely resistant (100 %) to penicillin. Resistances (12.5 % - 75 %) were also observed for fluoroquinolones, sulfamethoxazole-trimethoprim, tetracycline, rifampicin, erythromycin, and tobramycin. Isolates were susceptible to vancomycin (MICs <0.25-1 µg/mL) and teicoplanin (MICs <0.25-4 µg/mL). Intriguingly, 3/8 (37.5 %) CoNS isolates with the ERYRCLIS antibiotype expressed MLS-B phenotype. All isolates harboured blaZ gene. Seven (43.8 %) isolates carried mecA; and among them, the SCCmec Type III was the most frequent (n = 5/7; 71.4 %). Isolates also harboured seb, see, seg, sej, sem, etb, tsst, pvl, and hla toxin virulence-encoding genes (6.3 % - 25 %). A total of 12/16 (75 %) isolates were biofilm producers, while the icaAB gene was detected in an S. pasteuri isolate. Herein, it is shown that pet food is a potential source of clinically important Gram-positive bacterial pathogens. To the best of our knowledge, this is the first report of MLS-B phenotype and MR-CoNS in pet food in Latin America.

Asunto(s)

Antibacterianos , Clindamicina , Coagulasa , Pruebas de Sensibilidad Microbiana , Staphylococcus , Staphylococcus/efectos de los fármacos , Staphylococcus/genética , Staphylococcus/aislamiento & purificación , Brasil , Antibacterianos/farmacología , Coagulasa/metabolismo , Animales , Clindamicina/farmacología , Meticilina/farmacología , Alimentación Animal/microbiología , Microbiología de Alimentos , Mascotas/microbiología , Farmacorresistencia Bacteriana Múltiple/genética

RESUMEN

Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) are classified as high-risk infections that can lead to death, particularly among older individuals. Nowadays, plant nanoparticles such as glycyrrhizic acid are recognized as efficient bactericides against a wide range of bacterial strains. Recently, scientists have shown interest in plant extract nanoparticles, derived from natural sources, which can be synthesized into nanomaterials. Interestingly, glycyrrhizic acid is rich in antioxidants as well as antibacterial agents, and it exhibits no adverse effects on normal cells. In this study, glycyrrhizic acid nanoparticles (GA-NPs) were synthesized using the hydrothermal method and characterized through physicochemical techniques such as UV-visible spectrometry, DLS, zeta potential, and TEM. The antimicrobial activity of GA-NPs was investigated through various methods, including MIC assays, anti-biofilm activity assays, ATPase activity assays, and kill-time assays. The expression levels of mecA, mecR1, blaR1, and blaZ genes were measured by quantitative RT-qPCR. Additionally, the presence of the penicillin-binding protein 2a (PBP2a) protein of S. aureus and MRSA was evaluated by a Western blot assay. The results emphasized the fabrication of GA nanoparticles in spherical shapes with a diameter in the range of 40-50 nm. The data show that GA nanoparticles exhibit great bactericidal effectiveness against S. aureus and MRSA. The treatment with GA-NPs remarkably reduces the expression levels of the mecA, mecR1, blaR1, and blaZ genes. PBP2a expression in MRSA was significantly reduced after treatment with GA-NPs. Overall, this study demonstrates that glycyrrhizic acid nanoparticles have potent antibacterial activity, particularly against MRSA. This research elucidates the inhibition mechanism of glycyrrhizic acid, which involves the suppressing of PBP2a expression. This work emphasizes the importance of utilizing plant nanoparticles as effective antimicrobial agents against a broad spectrum of bacteria.

RESUMEN

Staphylococcus aureus is an important human and veterinary pathogen. The present study aimed to determine the prevalence of antibiotic resistance among S. aureus isolated from samples obtained from free-flying wild pigeons and houseflies from different locations surrounding a local hospital in the Greater Durban area in KwaZulu-Natal Province, South Africa. Environmental fecal samples were obtained from wild pigeons that inhabits the grounds of a local public hospital located on the South Beach area, Durban, South Africa. Housefly samples were collected from three different locations (Kenneth Stainbank Nature Reserve, Montclair/Clairwood, and Glenwood/Berea) in the greater Durban area, all within a close proximity to the hospital. Following enrichment, identification, and antimicrobial resistance profiling, S. aureus isolates were subjected to DNA extraction using the boiling method. It was found that 57 out of 252 samples (22.62%) were positive for S. aureus. The Kirby-Bauer disk diffusion method of antibiotic susceptibility testing was performed and revealed that antibiotic resistance rates to penicillin and rifampicin were the most common, with both returning 48 (84.2%) out of the 57 S. aureus isolates being resistant to penicillin and rifampicin. Antibiotic resistance rates to clindamycin, linezolid, erythromycin, tetracycline, cefoxitin, and ciprofloxacin were 82.5%, 78.9%, 73.7%, 63.2%, 33.3%, and 15.8% respectively. Antibiotic resistance genes were detected using primer-specific PCR and it was found that the prevalence rates of tetM, aac(6')-aph(2″), mecA, tetK, ermc, and blaZ genes were 66.7%, 40.4%, 40.4%, 38.6%, 24.6%, and 3.51% respectively. Statistical analysis revealed significant (p < 0.05) relationships between the tetM, aac(6')-aph(2″), and ermC genes and all parameters tested. A significant correlation between the aac(6')-aph(2″) gene and the tetM (0.506) and ermC (-0.386) genes was identified. It was found that 23 (40.3%) S. aureus isolates were mecA positive, of which 10 (52.6%) out of 19 cefoxitin-resistant isolates were mecA positive and 13 (35.1%) out of 37 cefoxitin-sensitive isolates were mecA positive. The results of the present study demonstrated the detection of methicillin and multidrug resistant S. aureus isolated from samples obtained from wild pigeons and houseflies in the surroundings of a local public hospital in the Greater Durban area in South Africa. The findings of the study may account for the emergence of multidrug-resistant staphylococcal infections. The findings highlight the significant role of wild pigeons and houseflies in the spread of drug-resistant pathogenic S. aureus including MRSA. The conclusions of the present study highlight the improtant role of wildlife and the environment as interconnected contributors of One Health.

RESUMEN

Objective: Staphylococcus haemolyticus can cause a series of infections including otitis media (OM), and the oxacillin-resistant S. haemolyticus has become a serious health concern. This study aimed to investigate the genomic characteristics of two strains of oxacillin-resistant and mecA-positive S. haemolyticus isolated from the samples of ear swabs from patients with OM and explore their acquired antibiotic resistance genes (ARGs) and the mobile genetic elements (MGEs). Methods: Two oxacillin-resistant S. haemolyticus strains, isolated from ear swab samples of patients with OM, underwent antimicrobial susceptibility evaluation, followed by whole-genome sequencing. The acquired ARGs and the MGEs carried by the ARGs, harbored by the genomes of two strains of S. haemolyticus were identified. Results: The two strains of oxacillin-resistant S. haemolyticus (strain SH1275 and strain SH9361) both carried the genetic contexts of mecA with high similarity with the SCCmec type V(5C2&5) subtype c. Surprisingly, the chromosomal aminoglycoside resistance gene aac(6')-aph(2") harbored by S. haemolyticus strain SH936 was flanked by two copies of IS256, forming the IS256-element (IS256-GNAT-[aac(6')-aph(2")]-IS256), which was widely present in strains of both Staphylococcus and Enterococcus genus. Furthermore, the two strains of oxacillin-resistant and MDR S. haemolyticus were found to harbor antimicrobial resistance plasmids, including one 26.9-kb plasmid (pSH1275-2) containing msr(A)-mph(C)) and qacA, one mobilizable plasmid pSH1275-3 harboring vga(A)LC, one plasmid (pSH9361-1) carrying erm(C), and one plasmid (pSH9361-2) carrying qacJ. Conclusion: The systematic analysis of whole-genome sequences provided insights into the mobile genetic elements responsible for multi-drug resistance in these two strains of oxacillin-resistant and mecA-positive S. haemolyticus, which will assist clinicians in devising precise, personalized, and clinical therapeutic strategies for treating otitis media caused by multi-drug resistant S. haemolyticus.

RESUMEN

OBJECTIVES: This multicenter study, conducted from a One Health perspective, aimed to comprehensively examine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infections and their biofilm-forming capabilities in Pakistan. Phylogenetic analysis of the study isolates was also performed. METHODS: A total of 150 MRSA isolates were screened from various clinical samples using Cefoxitin antibiotic discs. Genotypic confirmation was conducted through mecA, S. aureus-specific nuc, and 16S rRNA genes. Biofilm formation was assessed using Congo red agar (CRA) and slime layer quantification methods. The intercellular adhesion (ica) operon genes, specifically icaA and icaD, were detected. Phylogenetic analysis utilized the 16S rRNA sequences. Statistical associations between various parameters were determined using chi-square analysis. RESULTS: The presence of the mecA gene was observed in 131 out of 150 isolates (87.3%). CRA identified 28% and 40% of isolates as strong and moderate biofilm producers, respectively, while 9.3% were classified as non-biofilm producers. The slime layer assay exhibited higher sensitivity, classifying only 4.7% of isolates as non-biofilm producers. Biofilm-forming genes icaA and icaD were detected in 85.3% and 86.7% of the isolates, respectively. Antibiotic resistance was more prevalent among biofilm-forming isolates, particularly against ciprofloxacin, levofloxacin, erythromycin, trimethoprim-sulfamethoxazole, and fosfomycin. Ceftaroline demonstrated efficacy irrespective of biofilm-forming abilities. Conversely, non-biofilm producers exhibited complete susceptibility to clarithromycin and tigecycline. CONCLUSIONS: Clinical MRSA strains exhibit a substantial potential for biofilm formation, contributing to a resistant phenotype. Routine antibiotic testing in clinical settings that overlook the biofilm aspect may lead to the failure of empiric antibiotic therapy.

Asunto(s)

Antibacterianos , Biopelículas , Staphylococcus aureus Resistente a Meticilina , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Pakistán/epidemiología , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Humanos , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/epidemiología , Antibacterianos/farmacología , Filogenia , Farmacorresistencia Bacteriana , Proteínas Bacterianas/genética , ARN Ribosómico 16S/genética

RESUMEN

Background: Food safety is a serious challenge in the face of increasing population and diminishing resources. Staphylococcus aureus is a critical foodborne pathogen characterized by its capability to secret a diverse range of heat-resistant enterotoxins. Antibiotic usage in dairy herds resulted in the occurrence of antimicrobial resistance (AMR) patterns among bacterial species, which were consequently transmitted to humans via dairy products. Lactic acid bacteria (LAB) produce bacteriocins, which provide an excellent source of natural antimicrobials with the further advantage of being environmentally friendly and safe. Aim: Detection of multidrug resistance (MDR) S. aureus isolates in concerned samples, molecular characteristics, biofilm production, and the inhibitory role of LAB against it. Methods: Random samples of raw milk and other dairy products were analyzed for S. aureus isolation. Phenotypic and genotypic assessment of AMR was performed, in addition to detection of classical enterotoxin genes of S. aureus. Finally, evaluation of the antimicrobial action of some Lactobacillus strains against S. aureus. Results: Incidence rates of presumptive S. aureus in raw milk, Kariesh cheese, and yogurt samples were 50%, 40%, and 60%, respectively. The highest resistance of S. aureus was to Kanamycin (100%) and Nalidixic acid (89.3%), respectively. (78.66%) of S. aureus were MDR. 11.1% of S. aureus carried mecA gene. In concern with enterotoxins genes, PCR showed that examined isolates harbored sea with a percentage of (22.2%), while sed was found in (11.1%) of isolates. Regarding biofilm production, (88.88%) of S. aureus were biofilm producers. Finally, agar well diffusion showed that Lactobacillus acidophilus had the strongest antimicrobial action against S. aureus with inhibition zone diameter ranging from 18 to 22 mm. Conclusion: There is a widespread prevalence of MDR S. aureus in raw milk and dairy products. Production of staphylococcal enterotoxins, as well as biofilm production are responsible for public health risks. Therefore, installing proper hygienic routines and harsh food safety policies at food chain levels is substantial.

Asunto(s)

Antiinfecciosos , Probióticos , Infecciones Estafilocócicas , Humanos , Animales , Staphylococcus aureus/genética , Antibacterianos/farmacología , Factores de Virulencia/genética , Leche , Enterotoxinas/genética , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/veterinaria , Pruebas de Sensibilidad Microbiana/veterinaria , Biopelículas

RESUMEN

BACKGROUND: In Ethiopia, milk production and handling practices often lack proper hygiene measures, leading to the potential contamination of milk and milk products with Staphylococcus aureus (S. aureus), including methicillin-resistant strains, posing significant public health concerns. This study aimed to investigate the occurrence, antimicrobial susceptibility profiles and presence of resistance genes in S. aureus strains isolated from milk and milk products. METHODS: A cross-sectional study was conducted in the Arsi highlands, Oromia, Ethiopia from March 2022 to February 2023. A total of 503 milk and milk product samples were collected, comprising 259 raw milk, 219 cottage cheese, and 25 traditional yogurt samples. S. aureus isolation and coagulase-positive staphylococci enumeration were performed using Baird-Parker agar supplemented with tellurite and egg yolk. S. aureus was further characterized based on colony morphology, Gram stain, mannitol fermentation, catalase test, and coagulase test. Phenotypic antimicrobial resistance was assessed using the Kirby-Bauer disc diffusion method, while the polymerase chain reaction (PCR) was employed for confirming the presence of S. aureus and detecting antimicrobial resistance genes. RESULTS: S. aureus was detected in 24.9% of the milk and milk products, with the highest occurrence in raw milk (40.9%), followed by yogurt (20%), and cottage cheese (6.4%). The geometric mean for coagulase-positive staphylococci counts in raw milk, yogurt, and cottage cheese was 4.6, 3.8, and 3.2 log10 CFU/mL, respectively. Antimicrobial resistance analysis revealed high levels of resistance to ampicillin (89.7%) and penicillin G (87.2%), with 71.8% of the isolates demonstrating multidrug resistance. Of the 16 S. aureus isolates analyzed using PCR, all were found to carry the nuc gene, with the mecA and blaZ genes detected in 50% of these isolates each. CONCLUSION: This study revealed the widespread distribution of S. aureus in milk and milk products in the Arsi highlands of Ethiopia. The isolates displayed high resistance to ampicillin and penicillin, with a concerning level of multidrug resistance. The detection of the mecA and blaZ genes in selected isolates is of particular concern, highlighting a potential public health hazard and posing a challenge to effective antimicrobial treatment. These findings highlight the urgent need to enhance hygiene standards in milk and milk product handling and promote the rational use of antimicrobial drugs. Provision of adequate training for all individuals involved in the dairy sector can help minimize contamination. These measures are crucial in addressing the threats posed by S. aureus, including methicillin-resistant strains, and ensuring the safety of milk and its products for consumers.

Asunto(s)

Antiinfecciosos , Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Humanos , Animales , Staphylococcus aureus , Leche , Antibacterianos/farmacología , Staphylococcus aureus Resistente a Meticilina/genética , Coagulasa/genética , Etiopía , Estudios Transversales , Infecciones Estafilocócicas/epidemiología , Staphylococcus , Antiinfecciosos/farmacología , Ampicilina/farmacología , Pruebas de Sensibilidad Microbiana

RESUMEN

This case report documents the first instance of Penicillin-Susceptible Methicillin-Resistant Staphylococcus aureus (PS-MRSA) in a Chinese psychiatric hospital. The strain was isolated from a patient with Alzheimer's disease who had a lower respiratory tract infection. Clinical and laboratory analyses, including mass spectrometry, antibiotic susceptibility testing, and whole-genome sequencing, confirmed the PS-MRSA strain. In this case, we systematically introduce the clinical symptoms, laboratory findings, and treatment responses associated with this PS-MRSA strain. This discovery offers a new perspective on our understanding of resistance mechanisms and expands our considerations for existing antibiotic treatments. It may fill a gap in the classification of MRSA strains, enhance the spectrum of MRSA resistance, and complete the therapeutic strategies for MRSA.

RESUMEN

Methicillin-resistant Staphylococcus aureus (MRSA) transmission in livestock, community, and healthcare settings poses a significant public health concern both locally and globally. This study aimed to investigate the occurrence, molecular detection, and antibiogram of the MRSA strain in fresh beef, contact surfaces, and butchers' knives from the four major abattoirs (Karu, Gwagwalada, Deidei, and Kubwa) located in the Federal Capital Territory, Nigeria. A multi-stage sampling technique was used to collect 400 swab samples from butchers' knives (132), fresh beef (136), and contact surfaces (132). Presumptive colonies on mannitol salt agar were subjected to culture, isolation, and biotyping. The antibiogram was carried out via a Kirby-Bauer disk containing eight antibiotics. MRSA was phenotypically confirmed by oxacillin-resistant screening agar base (ORSAB) and genotypically by PCR to detect the presence of the mecA gene. Out of the 400 samples, 47.24% of fresh beef, 37% of contact surfaces, and 64.33% of butchers' knife swabs were Staphylococcus aureus positive. Thirty-two Staphylococcus aureus-positive isolates were confirmed to be MRSA, 50% fresh beef, 28.12% contact surfaces, and 21.87% butcher's knife swabs. MRSA isolates displayed multidrug-resistant traits, with a high resistance of 90.62% against cloxacillin, and a highest susceptibility of 100% to co-trimaxole. The antibiogram showed MRSA strains to be multidrug resistant. Molecular characterisation of the MRSA detected the presence of the mecA gene at a band size of 163 bp in all isolates. Strict hygiene of butchers, and working equipment in meat processing and marketing should be of top priority.

Asunto(s)

Staphylococcus aureus Resistente a Meticilina , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Animales , Nigeria , Infecciones Estafilocócicas/veterinaria , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/epidemiología , Bovinos , Pruebas de Sensibilidad Microbiana , Humanos , Antibacterianos/farmacología , Mataderos , Zoonosis/microbiología , Ganado/microbiología , Farmacorresistencia Bacteriana Múltiple/genética

RESUMEN

Background and Aim: There are numerous reports of subclinical mastitis cases in Blitar, which is consistent with the region's high milk production and dairy cattle population. Staphylococcus aureus, which is often the cause of mastitis cases, is widely known because of its multidrug-resistant properties and resistance to ß-lactam antibiotic class, especially the methicillin-resistant S. aureus (MRSA) strains. This study aimed to molecular detection and sequence analysis of the mecA gene in milk and farmer's hand swabs to show that dairy cattle are reservoirs of MRSA strains. Materials and Methods: A total of 113 milk samples and 39 farmers' hand swab samples were collected from a dairy farm for the isolation of S. aureus using Mannitol salt agar. The recovered isolates were further characterized using standard microbiological techniques. Isolates confirmed as S. aureus were tested for sensitivity to antibiotics. Oxacillin Resistance Screening Agar Base testing was used to confirm the presence of MRSA, whereas the mecA gene was detected by polymerase chain reaction and sequencing. Results: A total of 101 samples were confirmed to be S. aureus. There were 2 S. aureus isolates that were multidrug-resistant and 14 S. aureus isolates that were MRSA. The mecA gene was detected in 4/14 (28.6%) phenotypically identified MRSA isolates. Kinship analysis showed identical results between mecA from milk and farmers' hand swabs. No visible nucleotide variation was observed in the two mecA sequences of isolates from Blitar, East Java. Conclusion: The spread of MRSA is a serious problem because the risk of zoonotic transmission can occur not only to people who are close to livestock in the workplace, such as dairy farm workers but also to the wider community through the food chain.

RESUMEN

INTRODUCTION: this study aimed to isolate P. aeruginosa and S. aureus, investigate the antimicrobial resistance of collected isolates, and investigate the distribution of exoU and mecA genes in P. aeruginosa and S. aureus isolates. METHODOLOGY: Out of 150 samples, 32 isolates were identified as P. aeruginosa, 48 isolates were identified as S. aureus. All isolates were checked for AST. Then, a PCR was applied to detect exoU and mecA genes in P. aeruginosa and S. aureus. RESULTS: 12.0% and 29.3% of the samples showed co-isolates and single isolates of studied pathogens, respectively. Regarding burn samples, S. aureus was the most prevalent pathogen (38.0%, 38/100) among males (41.8%, 23/55), followed by P. aeruginosa (27.0%, 27/100) among females (28.9%, 13/45). The highest burn infection rates of S. aureus (50.0%) and P. aeruginosa (32.7%) were recorded among age groups (≥ 50) and (18-49), respectively. Comparatively, wound samples were less infected with these pathogens. P. aeruginosa isolates usually exhibited high resistance to gentamicin, tobramycin, and netilmicin, whereas, imipenem showed low resistance at 46.87%. S. aureus isolates were susceptible to trimethoprim-sulphamethoxazole and rifampin. 56.25% of P. aeruginosa isolates were exoU positive and 37.5% of S. aureus isolates were mecA positive. Results of the cefoxitin inhibition zone with mecA gene amplification, 33.3% isolates were MRSA, 4.2% isolates were nmrMRSA, and 62.5% isolates were MSSA. Most of the resistant isolates of P. aeruginosa carried the exoU gene, 80% resistant isolates to imipenem were exoU positive. CONCLUSIONS: S. aureus was more predominant than P. aeruginosa in burns and wounds infections.

Asunto(s)

Quemaduras , Staphylococcus aureus Resistente a Meticilina , Infecciones por Pseudomonas , Infecciones Estafilocócicas , Masculino , Femenino , Humanos , Staphylococcus aureus , Pseudomonas aeruginosa , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Prevalencia , Irak/epidemiología , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/tratamiento farmacológico , Pruebas de Sensibilidad Microbiana , Infecciones por Pseudomonas/tratamiento farmacológico , Imipenem