mecA Research Articles

Isolation, structural elucidation of bioactive compounds and their wound-healing ability, antibacterial and In silico molecular docking applications

Andrographis echioides has been extensively utilized in traditional Indian folk medicines for several skin disorders and other biological actions such as diuretic, antimicrobial, anthelmintic, anti-ulcer, and hepatoprotective properties. Different crude extracts were extracted from A. echioides leaves using various solvents such as methanol and water. The prepared crude extracts were utilized to formulate different herbal ointments. Further, the prepared ointments were examined against wounds and bacterial pathogens. The wound healing ability of the prepared formulations was observed for F1, F2, and F3, to be (89.84%, 95.11%, and 95.75%) respectively. Moreover, wound healing capabilities were compared with standard Betadine which exhibits 98.12%, those results indicating that the prepared herbal ointment also has a promising wound healing ability. The F2 formulations outperform the other two formulations (F1 and F2) in terms of their antibacterial ability to combat Staphylococcus aureus, Klebsiella pneumoniae Bacillus subtilis, and Escherichia coli. Moreover, there are two compounds were successfully isolated and identified from methanolic extract, which are 2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H-chromene-3,5,7-triol and 3-(3,4-Dihydroxyphenyl)-2-propenoic acid. Meanwhile, the molecular docking investigation exposed high binding energy Staphylococcus aureus TyrRS (−8.9 kcal/mol), Isoleucyl-tRNA synthetase (−7.5 kcal/mol), Penicillin-binding protein 2a (−8.0 kcal/mol), S. aureus DNA Gyrase (−7.2 kcal/mol), GSK-3beta (Glycogen synthase kinase-3 beta) (−8.3 kcal/mol) and TGF - Beta Receptor Type 1 Kinase Domain (−8.7 kcal/mol) indicating high degree of interaction between Compound-1 2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H-chromene-3,5,7-triol (DHPDHC) and 7 clinically important skin infective pathogen Staphylococcus aureus proteins at the active sites. Additionally, the standard drug Povidone iodine, Sulphothiazole, and Nitrofurazone (<−8 kcal/mol), displayed low binding affinity on targeted proteins. A molecular dynamics simulation research with high free energy showed stable interaction between the ligand and protein. Which endorses the capabilities of A. echioides derived compounds as a potential wound healer and antibacterial therapeutic candidate for drug development in the future.

Investigating the prevalence and function of the mecA gene and PBP2a protein among Staphylococcus and Mammaliicoccus species

Investigating the prevalence and function of the mecA gene and PBP2a protein among Staphylococcus and Mammaliicoccus species

Short Communication: Investigation of mecA-positive and Methicillin-Resistant Staphylococcus aureus (MRSA) in dairy goat with subclinical mastitis from traditional farms in Banyuwangi, Indonesia

Abstract. Praja RN, Edila R, Yudhana A, Saputro AL, Hamonangan JM, Praja SS. 2024. Short Communication: Investigation of mecA-positive and Methicillin-Resistant Staphylococcus aureus (MRSA) in dairy goat with subclinical mastitis from traditional farms in Banyuwangi, Indonesia. Biodiversitas 25: 1638-1643. Raw milk has the potential to transmit bacteria resistant to antibiotics and serve as a medium for the development of food-borne illnesses. Staphylococcus aureus is a harmful bacterium that can infect host cells and carry antibiotic-resistant genes. This study aims to investigate the occurrence of Methicillin-Resistant Staphylococcus aureus (MRSA) which contains mecA coding gene from raw goat milk in Banyuwangi, East Java, Indonesia. 150 raw milk samples were collected from five goat farms in Banyuwangi, East Java, Indonesia. S. aureus was isolated using selective media, and antibiotic susceptibility testing was conducted using the Mueller-Hinton agar diffusion method. MRSA was confirmed using the oxacillin and cefotaxime resistance screen agar test, with the presence of mecA genes identified through polymerase chain reaction. The results show that the prevalence of S. aureus was 30.6%. Of the 46 S. aureus isolates, 28 (60.87%) were categorized as MRSA. The mecA gene was observed in 9 (32.14%) MRSA isolates. The presence of MRSA in raw goat milk poses a significant public health threat, as bacteria carrying the mecA gene for antimicrobial resistance can spread through animal products like raw milk. Enhanced hygiene and sanitation protocols in dairy goat farms are essential prevention measures that must be strictly implemented.

Co-resistance to methicillin and clindamycin among coagulase-negative staphylococci isolates recovered from pet food in Brazil

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.

Occurrence, antimicrobial susceptibility, and resistance genes of Staphylococcus aureus in milk and milk products in the Arsi highlands of Ethiopia.

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. 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. 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. 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.

Molecular and epidemiological characterization of Staphylococcus aureus causing bovine mastitis in China

BackgroundStaphylococcus aureus is one of the most prevalent pathogens in bovine mastitis, which leads to substantial financial losses for the dairy industry. ResultsIn this study, S. aureus (n = 72) was isolated from 18 dairy farms in 15 provinces across China in 2021. The identification of these isolates at the species level was achieved by employing 16S rRNA sequencing. An isothermal amplification method for auxiliary detection of S. aureus was established, which can be employed not only for laboratory detection but also for point-of-care testing (POCT). Molecular characteristics of S. aureus mastitis in Chinese dairy cows were determined through MLST and spa typing. Finally, methicillin-resistant Staphylococcus aureus (MRSA) and MRSA resistance genes were detected using MIC and PCR amplification techniques. 72 isolates were identified as 12 sequence types (STs) and 7 clonal complexes (CC). ST1/CC1 was the dominant prevalent accounting for 33.3 % of the total, and exhibiting a wide distribution range. In terms of spa types, t114 was the dominant type, accounting for 31.9 % of the total, followed by t529 as the second major type. Four S. aureus strains were classified as MRSA according to their levels of oxacillin resistance (MIC ≥4 μg/mL). Among these four MRSA strains, one of them was found to be mecA positive. However, the presence of drug-resistance genes mecA and mecC was not detected in the remaining three MRSA strains, indicating the possible existence of new resistance genes. ConclusionsOur study investigated the prevalence of S. aureus mastitis in dairy cows in China, while also examined the molecular characteristics and MRSA strains. This information will help with the clinical monitoring, prevention, and control of S. aureus mastitis in dairy cattle.

Detection mecA gene and Staphylococcus aureus resistance to several antibiotics isolated from cat ear swabs at a veterinary hospital located at Surabaya – Indonesia

Gatos são suscetíveis a adquirir S.aureus que colonizam principalmente as narinas e os ouvidos de espécies de felinos. A otite externa no ouvido dos gatos é uma das doenças produzidas pelo S.aureus nos animais. A terapia com antibióticos é o tratamento convencional para as infecções produzidas pelo S.aureus. Os antibióticos utilizados durante o prolongado tratamento e o emprego de sub doses podem selecionar microorganismos resistentes. Com base em tais argumentos torna-se necessária a pesquisa de S.aureus isolados do ouvido dos gatos, bem como, a realização de testes para a resistência a antibióticos e do gene mecA. Empregando swabs estéreis de algodão foram obtidas amostras dos ouvidos dos gatos em meio de Amies. O isolamento bacteriano foi efetuado em meio MAS e os testes catalase e coagulase foram realizados para a identificação das bactérias. A sensibilidade dos isolados de S.aureus foi avaliada com o emprego de discos dos antibióticos cefoxitin, tetraxiclina, eritromicina, gentamicina e cloranfenicol, incorporados no meio MHA. Todos os isolados positivos de S.aureus foram submetidos ao test MRSA para a detecção do gene mecA. A amostra investigada revelou 91% (91/100) de positivos para S.aureus, dos quais, 3,30% (3/91) foram resistentes a múltiplas drogas (MDR) pois foram resistentes a 3-4 classes de antibióticos. De 12 MRSA isolados analisados o gene mecA foi detectado em um isolado. O uso inapropriado de antibióticos é a causa da resistência bacteriana em pets. Adicionalmente o emprego excessivo de antibióticos em uma população pode resultar no desenvolvimento de resistência bacteriana adquirida a antibióticos. O uso de antibióticos em animais deve ser ordenado por uma administração de medicamentos apropriada para prevenir o desenvolvimento da resistência.

Emerging threats of high biofilm formation and antibiotic resistance in clinical methicillin-resistant Staphylococcus aureus (MRSA) isolates from Pakistan

ObjectivesThis 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. MethodsA 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. ResultsThe 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. ConclusionsClinical 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.

Occurrence of antimicrobial resistance uropathogenic &lt;i&gt;Staphylococcus aureus&lt;/i&gt; isolates from pregnant women attending antenatal clinics within Ilorin

Background: Staphylococus aureus associated with urinary tract infection (UTI) has become a serious health problem especially with the emergence of methicillin resistant Staphylococus aureus (MRSA) due to the acquisition of mecA gene leading to increasing maternal and perinatal burden. This study aimed to evaluate the prevalence of antimicrobial resistance, β-lactamase production and methicillin resistance among uropathogenic S. aureus among pregnant women attending selected antenatal clinics in Ilorin.Methods: Forty-five (45) out of 79 presumptive uropathogenic S. aureus isolated over a period of 12 months from urine samples of pregnant women were identified using standard bacteriological methods. Antibiogram studies was performed using gentamicin (CN-10μg), ciprofloxacin (CIP-5μg), ofloxacin (OFX-5μg), tetracycline (TE-30μg), sulphamethaxozole-trimethoprim (SXT-25μg), ampicillin (AMP-10 μg), penicillin G (P-10 units), nitrofurantoin (F-30 μg) and cefoxitin (FOX-30 μg) for the detection of MRSA by disc diffusion method. Furthermore, detection of β - lactamase producing S. aureus (BL-PSA) was carried out using Iodometric paper strip method.Results: Of the 45 S. aureus isolates, 80% were BL-PSA, MRSA (87%), exhibiting high resistance to penicillin G (97.8%), ampicillin (95.5%), tetracycline (77.8%) and sulphamethaxozole trimethoprim (64.4%). In addition, 56% were multidrug-resistant (MDR) exhibiting 20 different phenotypes with CN-P-SXT-TE-AMP-FOX (15.6%) being the majority. Notwithstanding, S. aureus isolates showed high sensitivity to nitrofurantoin (93.3%) and ofloxacin (91.1%).Conclusion: This study established an increasing resistance of S. aureus to different classes of antibiotics which emphasize the need for constant surveillance to monitor antimicrobial resistance trends. Routine screening for BL-PSA and MRSA among uropathogenic S. aureus is also advocated in order to reduce the development and spread of MDR isolates.

Potential for Biofilm Formation and Antibiotic Resistance of Staphylococci Isolated from Bulk Tank Milk Samples

The prevalence of staphylococci in the environment of humans, including food, may lead to the production of toxins and food poisoning in consumers. Additionally, staphylococci constitute a reservoir of genes determining antibiotic resistance. The study aimed to compare the antibiotic resistance and biofilm-forming ability of staphylococci isolated from bulk tank milk and assess the occurrence of animal-associated methicillin-resistant Staphylococcus aureus. The study consisted of isolation of strains from cow milk, confirming their belonging to Staphylococcus sp. and S. aureus, investigation of the presence of a gene determining the production of coagulase, and genes determining resistance to β-lactams, tetracyclines, vancomycin, natural penicillins, and aminopenicillins, as well as virulence genes determining biofilm production. There were 56 bacterial strains isolated, which belong to Staphylococcus spp. All isolates showed resistance to amoxicillin, erythromycin, and tetracycline. The lowest resistance was demonstrated for vancomycin (48.2%). The mecA gene was not detected in any of the isolates and there was no positive reaction to the PB2 protein, which indicates that none of the isolated strains was methicillin resistant. Only 26.8% of isolated strains did not show the ability to produce biofilm. Special attention should be paid to the health of dairy cows and the supervision of the use of antibiotics in the dairy herd environment because, even in milk from healthy cows, there is a real risk of the occurrence of multi-drug resistant bacteria.

Resistant S. aureus Isolates Capable of Producing Biofilm from the Milk of Dairy Cows with Subclinical Mastitis in Slovakia

Staphylococcus spp. is the most common cause of mastitis, with a significantly low cure rate. Bacterial characteristics like adhesion and biofilm formation, as well as extracellular factors, can affect the pathogenesis of staphylococcal mastitis. The study’s objectives were to confirm S. aureus, assess their antibiotic resistance, identify methicillin resistance genes, verify biofilm formation, and detect biofilm-associated genes from bovine mastitis samples using multiplex PCR (mPCR). From 215 milk samples, six were confirmed as S. aureus. Most isolates were sensitive to all measured antibiotics. One isolate was identified as an inducible form of MLSB resistance (macrolides, lincosamides, and streptogramin B resistance), while the other two isolates were resistant to penicillins and carboxypenicillins. In S. aureus cultures used for methicillin resistance genotypic analysis by PCR, the mecA and mecC genes were not found. Biofilm formation phenotypes were determined in four strains. An mPCR analysis revealed that all strains of S. aureus carried icaABCD, agrA, srtA, fnbA, clfA, and clfB genes. Only in one isolate was the fnbB gene detected; the bap gene was not detected in any of the isolates. This emphasizes the importance of using appropriate treatment and continuous monitoring of S. aureus to prevent the spread of antibiotic-resistant strains in dairy cow farms.

Rabbit meat as a potential source of multidrug-resistant and enterotoxigenic &lt;i&gt;Staphylococcus aureus&lt;/i&gt; strains

Staphylococcus aureus in rabbit meat is a consequence of insufficient hygienic handling and improper processing posing a major health hazard. This study was conducted to assess rabbit meat as a potential source of Staphylococcus species, particularly Staphylococcus aureus (S. aureus). Furthermore, the identified S. aureus isolates were tested for the detection of the mecA virulence gene of methicillin-resistant Staphylococcus aureus (MRSA) and enterotoxin encoding genes (Sea, Seb, Sec, and Sed). A total of 80 samples of different rabbit meat cuts represented by shoulder, ribs, loin, and thigh (20 of each) were collected from various markets of different sanitation levels. The results obtained revealed that the mean counts of Staphylococcus species were 7.40×105, 7.58×105, 7.60×105 and 8.29×105 CFU/g in the examined shoulder, ribs, loin and thigh samples, respectively. Out of 17 identified S. aureus isolates, 5 (29.4%) strains were characterized by the presence of the mecA gene. A large proportion of the isolates obtained were resistant to at least three antibiotics. Enterotoxins were evaluated by ELISA. The results showed that three strains isolated from shoulder produced Sea, Seb, and Sec enterotoxins, the strains isolated from ribs failed to produce enterotoxins, while two strains isolated from loin and thigh produced Sea enterotoxin. The presence of S. aureus, especially MRSA strains, in the examined rabbit meat indicates the necessity of enforced application of strict hygienic measurements.

Phenotypic and Genotypic Study of Staphylococcus Haemolyticus and Staphylococcus Warneri Clinically Isolated from the Bloodstream

Background: The Staphylococcus haemolyticus and Staphylococcus warneri are coagulase-negative staphylococci (CoNS) as part of human skin’s natural flora. In recent years, CoNS has increased its visibility as opportunistic pathogens acquired in hospital patients. This study aims to isolate S. haemolyticus and S. warneri strains from patients with bloodstream infections and to analyze the antimicrobial profile of these bacteria by molecular detection of the mecA gene. Materials and Methods: Four hundred and twenty-three clinical blood samples were collected from patients admitted to general three hospitals in Hilla city, Iraq, during the period from September 2021 to July 2022. Blood samples were inoculated immediately into blood bottles containing 70 ml of Brain-Heart Infusion Broth. All isolates were identified by morphology, biochemical tests, and VITEK 2 automated system (bioMerieux, France). The Congo red agar plate test was used to detect biofilm production. The mecA gene was detected by conventional polymerase chain reaction. Results: S. haem olyticus (nine isolates) and S. warneri (six isolates) were detected out of 423 clinical blood samples. Molecular detection of the mecA gene was detected in all 15 isolates. As well 11 (73.3%) isolates were β-lactam resistant and biofilm production. The results of oxacillin-resistance minimum inhibitory concentration (MIC) (≥4 mg/ml) showed that 11 (73.3%) of the 15 isolates were oxacillin and methicillin-resistant CoNS (MR-CoNS). Susceptibility to various isolates (MICs µg/ml) using VITEK 2 system showed erythromycin (≥8 µg/ml), rifampin (≥4 µg/ml), clindamycin (≥4 µg/ml), and trimethoprim-sulfamethoxazole (≥4 µg/ml) resistance were (80%), (13.3%), (20%), and (53.3%), respectively. All isolates were (100%) sensitive to linezolid (≥8 µg/ml) and teicoplanin (≥32 µg/ml). Conclusions: The S. haemolyticus and S. warneri are serious infections associated with bacteremia and septicemia infections. Linezolid, teicoplanin, and rifampin are the drug of choice for the treatment of infections caused by MR-CoNS isolates. A high rate of the mecA gene and biofilm production is present in these bacteria.

Prevalence, molecular identification and determination of antibiotic susceptibility of methicillin-resistant Staphylococcus aureus in raw meat

Objective: The aim of this study was to determine the prevalence, molecular identification, and antibiotic susceptibility of MRSA in raw meats of retail sale in Balikesir, Turkey. Materials and Methods: A total of 250raw meat samples (beef n=100, chicken n=100, and turkey n=50) were collected from various supermarkets. Mueller-Hinton Broth medium containing 6.5% NaCl was used for pre-enrichment and Baird Parker Agar (BPA) was used as a selective medium. Polymerase Chain Reaction technique was used to confirm the suspected colonies with the nuc gene for S. aureus and the mecA gene for MRSA. Kirby-Bauer standard disc diffusion method was applied for antibiotic susceptibility of MRSA. Results: Of the 250 investigated raw meat samples, 21.2% were positive for S. aureus, which comprised 31% beef, 14% chicken, and 16 %turkey samples. Of the 250 investigated raw meat samples, 4% were positive for MRSA, which comprised 6% beef, 3% chicken, and 2% turkey samples. All MRSA isolates were found to be resistant to penicillin, sulfamethoxazole, trimethoprim, cefoxitin, and oxacillin, but they were susceptible to vancomycin. Conclusion: In recent years, MRSA has been called a zoonotic pathogen that poses a serious risk for food safety and public health. Therefore, we believe that this study will shed light on new studies on the prevalence of MRSA in various animal-originated foods.

ST8-t008-SCCmec IV methicillin-resistant Staphyloccoccus aureus (MRSA) in retail fresh cheese

This study reports the finding of 3 ST8-t008-SCCmec IVa (2B) MRSA strains in fresh cheese purchased within a single market in Costa Rica. In line with the finding of the resistance genes mecA, blaZ, mph(C), and msr(A) in their genomes, these bacteria showed phenotypic resistance to multiple β-lactams and erythromycin. Besides, they carry genes for acquired resistance to aminoglycosides (aph(3′)-III) and fosfomycin (fosD), mutations in genes associated with fluoroquinolone resistance (gyrA-85 and parC-80), and genes for a myriad of virulence factors, including adhesins, hemolysins, and exotoxins. Our strains share multiple genomic features with MRSA from the USA300 lineage, which is a widely distributed and highly virulent strain implicated in community infections. As a result, consuming these or similar products could lead to multidrug (MDR) infections in susceptible individuals. These results highlight safety deficiencies in cheese production practices and emphasize the risk of foodborne transmission of hard-to-treat ST8 MRSA strains.

Antibiotic Susceptibility of Staphylococcus Aureus with VanA and MecA Genes.

Staphylococcus aureus (S.aureus) is an emerging antibiotic resistant bacterium responsible for various infections in human. Resistance to methicillin and vancomycin are of prime concern in S. aureus. The study aims to determine the minimum inhibitory concentration (MIC) of Vancomycin and evaluate the existence of mecA and vanA genes, associated with antibiotic resistance. Clinical specimens from three Kathmandu hospitals were processed and S. aureus was identified using conventional microbiological procedures. MRSA was phenotypically identified with cefoxitin (30µg) disc diffusion, while vancomycin susceptibility was assessed using the Ezy MICTM stripes. The mecA and vanA genes were detected by polymerase chain reaction (PCR). Out of 266 S. aureus samples from various clinical specimen subjected for analysis, 77 (28.9%) were found methicillin-resistant (MRSA) and 10 (3.8%) were observed vancomycin-resistant (VRSA). Vancomycin resistant isolates showed a significant correlation between resistance to ampicillin, chloramphenicol, and cefoxitin. The mecA gene was found in 39 of the MRSA isolates, having 50.64% of MRSA cases, while the vanA gene was detected in 4 of the VRSA cases, constituting 40% of VRSA occurrences. The strains with higher vancomycin minimum inhibitory concentration values (≥ 1.5 μg/ml) displayed increased resistance rates to various antibiotics compared to strains with lower minimum inhibitory concentration values (< 1.5 μg/ml). The presence of vanA genes was strongly associated (100%) with vancomycin resistance, while the 10.3% mecA gene was identified from MRSA having resistance towards vancomycin also.

Identification of small molecule inhibitors of penicillin-binding protein 2a of methicillin-resistant Staphylococcus aureus for the therapeutics of bacterial infection.

The penicillin binding protein 2a (PBP2a) is a key enzyme associated with bacterial cell wall synthesis and bacterial infection. Therefore, targeting PBPa2 offers a promising approach for the therapeutics of bacterial resistance and infection. This study presents a comprehensive analysis of alpha-mangostin as a potential inhibitor of PBPa2. Molecular docking simulations revealed a strong binding affinity between alpha-mangostin and PBP2a, with an affinity score of -6.01 kcal/mol. Notably, alpha-mangostin formed a preferential hydrogen bond with THR216 of PBP2a, alongside several other polar and hydrophobic interactions. ADME and Toxicity predictions indicated that alpha-mangostin possesses favourable pharmacokinetic properties, suggesting its potential as a therapeutic agent. PASS analysis further highlighted its broad range of favourable biological properties. SwissTargetPrediction analysis reinforced these findings, indicating alpha-mangostin's association with various biological processes. Cell toxicity assays demonstrated that alpha-mangostin had no significant impact on the viability of HEK-293 cells, suggesting its potential safety for further development. The IC50 value for alpha-mangostin was found to be 33.43µM. Fluorescence-based binding assays showed that alpha-mangostin effectively inhibited PBP2a activity in a concentration-dependent manner, supporting its role as an inhibitor. In conclusion, the results suggest alpha-mangostin as a promising candidate for inhibiting PBP2a. Further, extensive studies are warranted to explore its clinical applications.

Distribution of resistance genes and resistance profile of methicillin-resistant Staphylococcus aureus among animal handlers in Animal Market, Jos

The problems associated with bacteria resistance to antibiotics are increasing despite spirited efforts to overcome the menace and its many attendants’ negative implications on human health and the related burden of failure by health institutions. The study characterized and determined the prevalence of resistance genes among animal handlers in livestock markets within Jos, Nigeria. Nose lining secretions and skin surface samples (384) were collected and bacteria were isolated from them. Isolates were characterized for methicillin and multidrug resistance, after which mecA and mecC presence was determined using molecular method. Seven bacterial species were isolated with the genus Staphylococcus having two species had 52.0% prevalence on skin surface and in nasal secretions. Thirty-three Staphylococcus aureus isolates were methicillin-resistant, and 37 skin surface and 34 nose secretions isolates were multidrug-resistant. mecA genes were present in 18 methicillin-resistant Staphylococcus aureus isolates obtained from the skin surface and 12 isolates from the nose lining. The study confirmed the presence of a high number of methicillin-resistant Staphylococcus aureus (MRSA) with mecA resistance regulatory gene.

Synergism with Shikimic Acid Restores β-Lactam Antibiotic Activity against Methicillin-Resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) has evolved into a dangerous pathogen resistant to beta-lactam antibiotics (BLAs) and has become a worrisome superbug. In this study, a strategy in which shikimic acid (SA), which has anti-inflammatory and antibacterial activity, is combined with BLAs to restart BLA activity was proposed for MRSA treatment. The synergistic effects of oxacillin combined with SA against oxacillin resistance in vitro and in vivo were investigated. The excellent synergistic effect of the oxacillin and SA combination was confirmed by performing the checkerboard assay, time-killing assay, live/dead bacterial cell viability assay, and assessing protein leakage. SEM showed that the cells in the control group had a regular, smooth, and intact surface. In contrast, oxacillin and SA or the combination treatment group exhibited different degrees of surface collapse. q-PCR indicated that the combination treatment group significantly inhibited the expression of the mecA gene. In vivo, we showed that the combination treatment increased the survival rate and decreased the bacterial load in mice. These results suggest that the combination of oxacillin with SA is considered an effective treatment option for MRSA, and the combination of SA with oxacillin in the treatment of MRSA is a novel strategy.

Prevalence and antimicrobial resistance profiles of mastitis causing bacteria isolated from dairy goats in Mukurweini Sub-County, Nyeri County, Kenya.

Ruminant mastitis continues to be a cause of economic losses in the dairy industry and remains a major public health hazard globally. This cross-sectional study was carried out in Mukurweini Sub-County of Nyeri County, Kenya, to investigate the prevalence of bacteria causing mastitis, risk factors associated with goat mastitis and the antibiotic resistance profiles of bacteria isolated from the goat milk. Farm level data on risk factors for mastitis was obtained from 56 farmers using a semi structured questionnaire. A total of 189 goat milk samples were collected. The goat's udder was observed for signs of clinical mastitis and the California Mastitis Test (CMT) used to test the milk for sub-clinical mastitis. All samples were then cultured for morphological identification of bacteria and strain typing by Matrix Assisted Laser Desorption/Ionization (MALDI)-Time of Flight (ToF) technique. Antimicrobial susceptibility of the isolated Staphylococcus aureus, coagulase-negative Staphylococcus (CoNS), Escherichia coli, Klebsiella oxytoca, Pseudomonas spp., Enterobacter spp., Proteus vulgaris and Escherichia vulneris to eight commonly used antibiotics was done by the disc diffusion method and validated by determining the presence of antibiotic resistance genes (mecA and blaTEM) using polymerase chain reaction method. The prevalence of clinical mastitis was 1.1% (2/189) while that of sub-clinical mastitis was 84.7% (160/189). Higher (p<0.05) prevalence of mastitis was observed in goats whose houses were cleaned fortnightly and in cases where farmers used same towel to dry different does' udders during the milking process. Thirteen different bacterial species were isolated from the milk samples and identified by MALDI-ToF, and these included S. aureus (22.0%), CoNS (20.3%), E. coli (18.1%), Pseudomonas spp. (14.3%), Enterobacter spp. (10.4%), K. oxytoca (6.0%), E. vulneris (1.7%), P. vulgaris (1.7%), Raoutella ornithinolytica (1.7%), Stenotrophomonas maltophilia (1.1%), Pantoea agglomerans (1.1%), Serratia marcescens (1.1%) and Cedeceas spp. (0.6%). One hundred pathogenic bacterial isolates were randomly selected and tested for antibiotic sensitivity to eight antibiotics out of which S. aureus were 97.5% resistant to Oxacillin and 100% sensitive to Ciprofloxacin. The CoNSs were 100% resistant to Oxacillin and 100% sensitive to Ciprofloxacin. E. coli were 93.9% resistant to Oxacillin, 69.7% sensitive to Ciprofloxacin and 87.9% sensitive to both Amoxicillin/Clavulanic acid and Meropenem. The antimicrobial resistant genes detected in S. aureus and E. coli were mecA [66.7%, 0%], and blaTEM [20% and 78.3%], respectively. In conclusion, the study showed that most of the does were affected by subclinical mastitis with the main causative bacteria being Staphylococci spp. and coliforms. Farmers need to be trained on improved control of mastitis by adoption of good milking practices and use of CMT kit for early detection of mastitis. Occurrence of multidrug resistance by key mastitis causing pathogens was shown to be prevalent and therefore there is need for development of intervention strategies.