Methicillin-resistant Staphylococcal Strains Research Articles

Increase in methicillin-resistant Staphylococcus spp. colonization among pregnant individuals during COVID-19 pandemic

Methicillin-resistant Staphylococcus (MRS) has been associated with neonatal infections, with colonization of the anovaginal tract being the main source of vertical transmission. The COVID-19 pandemic has altered the frequency of antibiotic usage, potentially contributing to changes in the dynamics of bacterial agents colonizing humans. Here we determined MRS colonization rates among pregnant individuals attending a single maternity in Rio de Janeiro, Brazil before (January 2019–March 2020) and during (May 2020–March 2021) the COVID-19 pandemic. Anovaginal samples (n = 806 [521 samples before and 285 during the pandemic]) were streaked onto chromogenic media. Colonies were identified by MALDI-TOF MS. Detection of mecA gene and SCCmec typing were assessed by PCR and antimicrobial susceptibility testing was done according to CLSI guidelines. After the onset of the pandemic, MRS colonization rates increased significantly (p < 0.05) from 8.6% (45) to 54.7% (156). Overall, 215 (26.6%) MRS isolates were detected, of which S. haemolyticus was the most prevalent species (MRSH, 84.2%; 181 isolates). SCCmec type V was the most frequent among MRS (63.3%; 136), and 31.6% (68) of MRS strains had a non-typeable SCCmec, due to new combinations of ccr and mecA complexes. Among MRS strains, 41.9% (90) were resistant to at least 3 different classes of antimicrobial agents, and 60% (54) of them were S. haemolyticus harboring SCCmec V. MRS colonization rates and the emergence of multidrug-resistant variants detected in this study indicate the need for continuing surveillance of this important pathogen within maternal and child populations.

Antimicrobial peptidase lysostaphin at subinhibitory concentrations modulates staphylococcal adherence, biofilm formation, and toxin production

BackgroundThe ability of antimicrobial agents to affect microbial adherence to eukaryotic cell surfaces is a promising antivirulence strategy for combating the global threat of antimicrobial resistance. Inadequate use of antimicrobials has led to widespread instances of suboptimal antibiotic concentrations around infection sites. Therefore, we aimed to examine the varying effect of an antimicrobial peptidase lysostaphin (APLss) on staphylococcal adherence to host cells, biofilm biomass formation, and toxin production as a probable method for mitigating staphylococcal virulence.ResultsInitially, soluble expression in E. coli and subsequent purification by immobilized-Ni2+ affinity chromatography (IMAC) enabled us to successfully produce a large quantity of highly pure ~ 28-kDa His-tagged mature APLss. The purified protein exhibited potent inhibitory effects against both methicillin-sensitive and methicillin-resistant staphylococcal strains, with minimal inhibitory concentrations (MICs) ranging from 1 to 2 µg/mL, and ultrastructural analysis revealed that APLss-induced concentration-specific changes in the morphological architecture of staphylococcal surface membranes. Furthermore, spectrophotometric and fluorescence microscopy revealed that incubating staphylococcal strains with sub-MIC and MIC of APLss significantly inhibited staphylococcal adherence to human vaginal epithelial cells and biofilm biomass formation. Ultimately, transcriptional investigations revealed that APLss inhibited the expression of agrA (quorum sensing effector) and other virulence genes related to toxin synthesis.ConclusionsOverall, APLss dose-dependently inhibited adhesion to host cell surfaces and staphylococcal-associated virulence factors, warranting further investigation as a potential anti-staphylococcal agent with an antiadhesive mechanism of action using in vivo models of staphylococcal toxic shock syndrome.

Natural cordiaquinones as strategies to inhibit the growth and biofilm formation of methicillin-sensitive and methicillin-resistant Staphylococcus spp.

The aim of this study was to investigate the antibacterial and antibiofilm potential of cordiaquinones B, E, L, N, and O against different Staphylococci strains, in addition to analyzing in silico the observed effect. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined according to CLSI guidelines. The inhibition of biofilm formation was investigated at sub-MICs. Atomic force microscopy (AFM) and density functional theory method were performed. The tested strains of Staphylococcus spp. were susceptible to cordiaquinones B, E, and L, among which cordiaquinone B exerted a bactericidal effect, confirmed by a bacterial growth curve study, against Staphylococcus saprophyticus. Cordiaquinones B and E showed lowest MBC values against S. saprophyticus. AFM revealed that cordiaquinone L reduced the mean cell size of S. saprophyticus. Cordiaquinones B and E inhibited the biofilm formation ability of S. aureus by ∼90%. The in silico analysis suggested that the antimicrobial activity of cordiaquinones is driven by their electron donation capability. Cordiaquinones inhibit the growth and biofilm formation (virulence factor) of both methicillin-sensitive and methicillin-resistant Staphylococci strains, indicating their antimicrobial potential.

Community acquired methicillin resistant Staphylococci (CA-MRS) in fecal matter of wild birds – A ‘one health’ point of concern

BackgroundAntibiotic resistance in Staphylococci, particularly methicillin resistance is a major public health concern. While this problem has been reported from the clinical settings, its presence in non-clinical settings also needs to be investigated. The role of wildlife in carrying and disseminating the resistant strains has been established in different studies but its role in Pakistani environment has not been explored yet. To evaluate this, we investigated the carriage of antibiotic resistant Staphylococci in wild birds from Islamabad region. MethodologyBirds fecal matter were collected during September 2016-August 2017 from eight different environmental settings of Islamabad. Prevalence of Staphylococci, their susceptibility profile against eight classes of antibiotics through disc diffusion method, their SCCmec types, co-resistance of macrolide and cefoxitin through PCR assay and biofilm formation through microtitre plate assay were studied. ResultsOut of 320 birds feces collected, 394 Staphylococci were isolated, where 165 (42%) were resistant to at least one or two classes of antibiotics. High resistance was found against erythromycin (40%) and tetracycline (21%) while cefoxitin resistance was 18% and vancomycin resistance was only in 2%. One hundred and three (26%) isolates exhibited multi-drug resistance (MDR) pattern. mecA gene was detected in 45/70 (64%) cefoxitin resistant isolates. Community acquired methicillin resistant Staphylococci (CA-MRS) were 87% while Hospital acquired methicillin resistant Staphylococci (HA-MRS) were 40%. In the MRS isolates showing co-resistance to macrolides, mefA (69%) and ermC (50%) genes were more prevalent. Strong biofilm formation was observed in 90% of the MRS, of which 48% were methicillin resistant Staphylococcus aureus (MRSA) isolates while 52% were methicillin resistant coagulase negative Staphylococci (MRCoNS). ConclusionOccurrence of methicillin resistant strains of Staphylococci in wild birds suggests their role in the carriage and dissemination of resistant strains into the environment. The findings of the study strongly recommend the monitoring of resistant bacteria in wild birds and wildlife.

Neonatal Bacteraemia and Antibiotic Resistance at the Angre University Hospital, Abidjan, 2020

Background: Multi-drug resistant bacteria are an increasingly important cause of neonatal sepsis. Nowadays, they are a great concern in neonates because few therapeutic options are available. Aim: To determine the bacteria responsible of neonatal sepsis and their antibiotic susceptibility pattern in order to improve the quality of antibiotic prescription. Methods: A retrospective data review on positive blood cultures from the neonatal department at the university hospital of Angre between January to December 2020 was conducted. All neonates with clinical suspicion of sepsis with positive blood cultures were identified. Patient demographics, clinical details, and laboratory data were recorded and analyzed by Epi info software version 7.2.5.0 Results: Out of 221 blood cultures samples, 82 were positive (37%). The predominant age group was that between day 0 and day 7. A preponderance of bacteria of the genus Staphylococcus (48.78%) compared to enterobacteria (43.90%) was observed. The main isolated bacteria were coagulase-negative Staphylococcus (29.27%), Klebsiella pneumoniae (26.83%) and Staphylococcus aureus (19.51%). Streptococcus agalactiae was isolated in 2 cases (2.44%). Among the Enterobacteriaceae strains, 80.56% produced an Extended Spectrum Beta-Lactamase (ESBL). The rate of methicillin-resistant was observed in coagulase-negative Staphylococcus and Staphylococcus aureus in 37.50% and 31.25% of cases respectively. Out of ESBL strains, 89.65% were multi-resistant. Of the 14 strains of methicillin-resistant staphylococci, 13 (92.86%) were multidrug resistant. Conclusion: Coagulase-negative Staphylococcus and Klebsiella pneumoniae were the common causes of neonatal sepsis. The high rate of multi-drug resistant bacteria resistant represents a great threat to neonatal survival and warrants modification of existing empirical therapy.

Methicillin-Resistant Staphyloccocus aureus Contamination in Hospital Door Handles of Pokhara, Nepal

The presence of contaminants on the door handles surfaces of hospitals may be a common means of transfer of potentially pathogenic bacteria among users and can act as vehicles of diseases transmission. The aim of this study was to isolate, identify and evaluate the presence of bacterial contaminants and Methicillin Resistant Staphylococci (MRSA) with their antimicrobial susceptibility pattern present on the door handles of selected hospitals of Pokhara Metropolitan City, Western Nepal to take the necessary remedial measures. Isolation, identification and antimicrobial susceptibility test of bacteria were done using standard microbiological procedures. Further screening and confirmation of MRSA were done according to Clinical Laboratory Standard Institutes (CLSI) guidelines. Out of the 100 swab samples cultured, 96 (96%) showed bacterial growth. 62.86% (88/140) of the isolates were found to be Gram positive. Percentage distribution of the isolates showed that the most prevalent Gram-positive bacteria identified was Staphylococcus aureus (43.18%), followed by Coagulase negative Staphylococci (15.91%), Bacillus spp (11.36%), Diptheroides (10.23%) but considerable number of Micrococci (7.95%), Streptococcus pneumoniae (6.82%), Enterococci (4.55%). Prevalence of MRSA in this study was 39.47%. Significant difference in antibiotic resistance pattern was found among MRSA and MSSA isolates (P&lt;0.05) reflecting increased ability of MRSA to develop resistance against various antimicrobials. Drugs like clindamycin, cefazoline and amikacin were found quite effective against MRSA in the present study would be better options for the management of such infections. MRSA strains’ contaminating on the door handles of hospitals may cause threat of infections to patients, hospital staffs, visitors to hospitals and people in the community. Thus, regular surveillance and disinfection with appropriate agent at regular interval would minimize the settlement and transmission of various pathogens including MRSA.Keywords: Contaminants; disinfection; door handles; hospital; MRSA; pathogen

Synthesis, Structural Characterization and Biological Activity Evaluation of Novel Cu(II) Complexes with 3-(trifluoromethyl)phenylthiourea Derivatives.

Copper complexes with 1,3-disubstituted thiourea derivatives, all containing 3-(trifluoromethyl)phenyl tail and 1-alkyl/halogen-phenyl substituent, were synthesized. The experimental spectroscopic studies and theoretical calculation revealed that two ligands coordinate to Cu(II) in a bidentate fashion via thiocarbonyl S and deprotonated N atoms of thiourea moiety. Such monomers are characteristic of alkylphenylthiourea complexes, whereas the formation of a sandwich-type dimer is observed for halogeno derivatives. For the first time, the structural identifications of CuN2S2-based complexes using experimental and theoretical X-ray absorption near edge structure are demonstrated. The dimeric halogeno derivatives showed higher antimicrobial activity in comparison with alkylphenylthiourea complexes. The Cu(II) complex of 1-(4-chloro-3-nitrophenyl)-3-[3-(trifluoromethyl)phenyl]thiourea was active against 19 strains of methicillin-resistant Staphylococci (MIC = 2 µg/mL). This derivative acted as a dual inhibitor of DNA gyrase and topoisomerase IV isolated from Staphylococcus aureus. Additionally, complexes of halogenphenylthiourea strongly inhibited the growth of mycobacteria isolated from tuberculosis patients, even fourfold stronger than the reference isoniazid. The complexes exerted weak to moderate antitumor activity (towards SW480, SW620, and PC3) being non-toxic towards normal HaCaT cells.

THE SIGNIFICANCE OF METICYLIN-RESISTANT STAPHYLOCOCCUS IN THE DEVELOPMENT OF SEPTIC INFECTIONS (IN THE MODEL OF PULMONARY INFLAMMATION/DESTRUCTION)

Septic infections caused by methicillin-resistant Staphylococcus (MRS) are one of the most important challenges for modern medicine. The results of the study showed that MRS strains isolated from patients with pulmonary inflammation/destruction had much higher rates of antibiotic resistance compared to methicillin-sensitive Staphylococcus strains (MSS). At the same time, the clinical and socio-economic impact of patients with pulmonary inflammation with MRS is more significant compared to that of patients with MSS, requiring more expensive treatment over a longer period of time (13.81 days vs. 7.05 days) and more days of hospitalization (18.4 days vs. 11.3 days), including in the intensive care units (9.23 days vs. 2.25 days), as well as increased lethality (8.6% vs. 2.5 %).

Susceptibility of drug-resistant staphylococci isolated from different parts of the ocular anterior segment to common ophthalmic antibiotics

Objectie To investigate the susceptibility of drug-resistant staphylococci isolated from different parts of the anterior segment to levofloxacin, tobramycin, cefazolin sodium, fusidic acid and clindamycin. Methods: Experimental Study. A total of 67 patients with anterior segment infection (33 cases of conjunctivitis, 6 cases of bacterial keratitis, 7 cases of blepharitis, 9 cases of neonatal dacryocystitis, 9 cases of neonatal dacryocystitis, 1 case of adult dacryocystitis and 11 cases of other infectious eye diseases) were collected from the conjunctival sac, cornea, eyelid margin and lacrimal sac. Minimum inhibitory concentration (MIC) determination of methicillin-resistant Staphylococcus (MRS) strains and β-lactamase-producing (β-Lac) strains by a micro-liquid-based method, according to the M100 standard of the American Institute for Clinical and Laboratory Standardization Susceptibility and resistance determinations were made. Data were statistically analyzed using Chi-square or Fisher's exact test. Results: Thirty-five MRS, 30 β-Lac and 2 β-Lac MRS isolates were identified from 67 multidrug-resistant Staphylococcus . There were 3, 9, 4, and 19 MRS isolates isolated from the lacrimal sac, cornea, eyelid margin and conjunctival sac, accounting for 3/4, 9/12, 4/8, 19/43 (44.2%) of the isolated sites respectively. There were 1, 3, 3, and 23 β-Lac isolates, accounting for 1/4, 3/12, 3/8 and 23/43 (53.5%) of the isolated sites, respectively. The highest proportion of β-Lac isolates isolated from patients with a diagnosis of conjunctivitis was 17 (25.3%) from the conjunctival sac. Among the MRS strains isolated from the cornea and lacrimal sac, 5 (7.5%) and 3 (4.5%) were from patients diagnosed with bacterial keratitis and neonatal tear, respectively. The number of MRS strains and β-Lac isolates isolated from patients with a diagnosis of blepharitis were both 3 (4.5%) from the lid margin.Among the strains isolated from the eyelid margin and the conjunctival sac, drug-resistant Staphylococcus epidermidis was the main strain, the drug-resistant Staphylococcus aureus was the major isolates in lacrimal sac and cornea. Among the 35 MRS isoaltes, 25, 24, 12, 12, and 11 were sensitive to cefazolin sodium, fusidic acid, levofloxacin, clindamycin and tobramycin, and the sensitivity rates were 71.4%, 68.6%, 34.3%, 34.3% and 31.4%, the difference was statistically significant (χ2=22.756, P<0.001), The sensitivity rates of levofloxacin, tobramycin, cefazolin sodium, fusidic acid and clindamycin against MRS isolates from the anterior segment were both statistically significant differences (χ2=18.493, 11.594, 8.906, 9.841, 16.059; all P<0.05). The susceptibility rates of MRS isolates against five antibiotics was statistically significant differences (χ2=33.080, P<0.001). Among the 30 β-Lac isolates, 27, 22, 19, 16, and 8 were sensitive to cefazolin sodium, fusidic acid, levofloxacin, tobramycin and clindamycin, and the sensitivity rates were 90.0 % , 73.3%, 63.3%, 53.3% and 26.7%, the difference was statistically significant (χ2=28.280, P<0.001). The sensitivity rates of five antibiotics against β-Lac isolates from the anterior segment were both statistically significant differences (χ2=50.971, 24.543, 48.147, 44.899, 18.676; all P<0.001). The susceptibility rates of β-Lac isolates against five antibiotics was statistically significant differences (χ2=23.383, P<0.001). The sensitivity of cefazolin sodium and fusidic acid against β-Lac isolates were higher than MRS isolates. Conclusions: Cefazolin sodium and fusidic acid may be the best choice for the treatment of drug-resistant Staphylococcus isolated from anterior conjunctival sac, cornea, eyelid margin and lacrimal sac, especially for β-Lac-producing drug-resistant Staphylococcus infection.

Therapeutic Drug Monitoring for Evaluation of the Efficacy and Safety of Vancomycin in Patients with Orthopaedic Infections

Vancomycin is a drug of choice for the infections caused by methicillin-resistant strains of staphylococci. Its use requires individualised dosing and renal function monitoring.The aim of the study was to evaluate, using therapeutic drug monitoring (TDM), the frequency of reaching target trough serum concentrations (TSCs) and the frequency of renal function impairment in orthopaedic infection patients receiving vancomycin therapy.Materials and methods: the authors carried out a retrospective analysis of vancomycin TSC test results of 457 patients admitted to a purulent osteology department in 2019–2021. The results were grouped according to the number of TSC determination performed as part of TDM (tests 1, 2, and 3). Each of the 3 groups was further divided into 4 subgroups according to the TSCs of vancomycin: ≤9.9 µg/ml (extremely low), 10–14.9 µg/ml (recommended for mild infections), 15–19.9 µg/ml (recommended for bone and joint infections), ≥20 µg/ml (potentially toxic). The results obtained in each group were analysed separately.Results: according to the 1st TDM test, only 9.6% of patients achieved the TSCs of vancomycin recommended for bone and joint infections. Extremely low TSCs, insufficient for treatment of the infections, were found in 64.8% of patients. According to the 2nd and 3rd TSC determinations, dose corrections decreased the percentage of patients with extremely low TSCs to 49.9% and 41.2%, respectively. Potentially toxic TSCs of vancomycin were detected in 48 (10.5%) patients, but renal dysfunction was observed only in 8 (1.75%) of them. The authors exemplify the use of TDM to control the efficacy and safety of vancomycin in patients with pronounced signs of renal function impairment by two clinical cases.Conclusion: with a standard dose of vancomycin, the concentrations recommended for bone and joint infections were reached only in every tenth patient. There was a large percentage of patients with extremely low serum concentrations of the medicinal product (64.8%), but it decreased after dose adjustments. Monitoring of vancomycin concentrations allows for individualised dosing, efficacy control and significant reduction of the risk of adverse kidney reactions.

The Array of Antibacterial Action of Protocatechuic Acid Ethyl Ester and Erythromycin on Staphylococcal Strains.

The spread of antibiotic resistance among bacteria has become one of the major health problems worldwide. Methicillin-resistant staphylococcal strains are especially dangerous because they are often resistant to other antibiotics. The increasing insensitivity to macrolides, lincosamides and streptogramin B antibiotics of methicillin-resistant staphylococcal isolates has limited the use of these drugs in therapy. The combination of natural compounds and antibiotics can be considered as an alternative tool to fight multi-drug-resistant pathogen infections. The aim of the presented study was to examine the antibacterial activity of protocatechuic acid ethyl ester–erythromycin combination towards Staphylococcus aureus and Staphylococcus epidermidis strains with various resistance profiles to methicillin and macrolides, lincosamides and streptogramin B (MLSB) antibiotics. The in-vitro antibacterial potential of the above combination was investigated by minimum inhibitory concentration assays and checkerboard testing. The observed effects were strain dependent, with 8 of 12 tested staphylococcal strains showing an indifferent effect on the natural compound and erythromycin; for 2 strains, the tested combination had an additive effect, while for another 2, the effect was synergistic. Interestingly, the multi-drug-resistant strains were more sensitive to the cooperative action of the protocatechuic acid ethyl ester and the antibiotic.

#77 Prevalence of Staphylococcus aureus bacteremia at Saint Damien Hospital, Nos Petits Frères et Sœurs January (HSD/NPFS) 2020-June 2021, Haiti

Abstract Background Staphylococcus Aureus (SA) is one of the main agents implicated in healthcare-associated infections (HAI) [1]. These infections are associated with significant morbidity and mortality, particularly methicillin-resistant staphylococcal (MRSA) infections, and their costs are also a concern. Bacteremia is regularly monitored at Saint Damien Hospital (HSD), for the year 2020 an increase in Staphylococcus aureus (SA) bacteremia was observed in certain units of the hospital. In this context, all SA infections were reviewed during eighteen months to determine the prevalence of methicillin-resistant (MRSA) and methicillin-sensitive (MSSA) staphylococcus aureus infections, their origins: in healthcare-associated infections (HAI), community-acquired infections (CI) and the distribution of MRSA per unit Method A Descriptive retrospective study was carried out at Saint Damien Hospital from January 2020 to June 2021. It includes all hospitalized children under fourteen years old (14) who had a positive blood culture for SA per site, only the 1st blood culture was taken into account. According to NHSN/CDC, are defined as infections associated with healthcare-associated infections occurring at ≥ 72 hours of hospitalization (HAI) and as community-acquired infectious infections occurring at = &amp;lt; 48 hours of hospitalization.. Data were collected from microbiology laboratory registers and patient records Results From January 2020 to June 2021, two thousand two hundred thirty five 2235 blood cultures were performed. The positivity rate was 21.43% (n=479/2235) distributed in different units. 16.49% SA strains were isolated (n=79/479), including fifty (50) strains of MRSA (63.29%) and twenty nine (29) strains of MSSA (36.70%) (n=29/79).From the strains of MRSA, 54% (n=27/50) were HAI and 46% community infections (CI) (n=23/50). The Origin of the infections (HAI/CI) was not significantly associated with MRSA and MSSA strains (p=0.6235), MRSA mainly came from emergency 48% (n=24/50) followed by neonatology 20% (n=10/50), intensive care 10% (5/50) and oncology at 10% (5/50). (n=19/79), the mortality rate attributable to MRSA and MSSA was 28% (n=14/50) and 17.24% (n=5/29), respectively. 46% of MRSA were resistant to more than 3 families of antibiotics (n = 23/50). SA strains were resistant to gentamycin at 30.37% (n=24/79) to 54.34% to sulfametoxazole (n=43/79) and 18.98% and to vancomycin (n=15/79 Conclusion The frequency of SA infections, specifically MRSA, is of great concern. Its existence in the community and its multiresistance, in particular to vancomycin, is an alert making this bacteremia a priority at Saint Damien Hospital, the standard precautions measures, the proper use of antibiotics by clinicians and epidemiological surveillance local would be needed to help control its spread.

PHENOTYPIC CHARACTERIZATION OF METHICILLIN-RESISTANT STAPHYLOCOCCAL STRAINS ISOLATED FROM DAIRY CATTLE IN A RURAL COMMUNITY

The emergence of methicillin-resistant staphylococci among livestock production have revealed different epidemiological dimension to the understanding of the staphylococcal infection. The aim of this study was to investigate methicillin-resistant staphylococcal strains isolated from raw milk and nasal cavity from free range dairy cattle in rural community using phenotypic profiling. A total of 283 samples were examined from free range dairy cattle (137 milk samples and 146 nasal swabs) were assessed between February and April 2015. Staphylococcal were isolated and positively identified using morphological and biochemical reactions. Of the 283 samples, 100 isolates (50 nasal and 50 milk samples) were methicillin-resistant Staphylococcus species and were further characterized by phenotypic methods. The antimicrobial resistance profiles of the isolates were determined using the phenotypic disc diffusion method. Phenotypic characterization using Modified Hodge Test showed that 45/50 (90%) and 48/50 (96%) of the isolates from nasal and raw milk revealed carbapernemase activity respectively. Also, 2/50 (4%) of the isolates from the nasal cavity and 4/50 (8%) of the isolates from raw milk were positive to Double Disc Synergistic Test and thus revealing metallo-?-lactamases (MBLs) production. Extended spectrum beta-lactamase activity, carbapenemase activity and metallo-beta-lactamase activity producing isolates are becoming prevalent in food animal settings. The detection of staphylococcal strains that are phenotypically resistant to oxacillin and methicillin are known to pose serious health concerns and are of great clinical relevance.

Effect of enterocins against methicillin-resistant animal-derived staphylococci.

The occurence and spread of animal-derived methicillin resistant staphylococci (MRS) worldwide is acurrent problem, especially due to their increasing incidence in food animals and their products, with possible contamination of food consumers and handlers. Staphylococci isolated from animals (n = 123) were identified with MALDI-TOF mass spectrometry and screened for methicillin/oxacillin/cefoxitin resistance (MR) using the disk diffusion method. Twenty-three phenotypically MRS strains were analysed using PBP2' Latex Agglutination Test Kit to confirm the phenotypic MR and PCR was performed for mecAgene detection; mecA gene positive strains were furtherly confirmed by means of sequencing. The susceptibility of MRS to 11 partially-purified enterocins (Ent) produced by E. faecium, E. durans and E. mundtii strains of animal, feed/food and environmental origin was checked using agar spot tests. Out of 23 MRS, PBP testing confirmed MR in 17 strains. Three Staphylococcus epidermidis and oneS. vitulinus weremecA positive. The majority of MRS, including two mecA gene-positive strains S. epidermidis R44/1 and P3/Tr2a, were susceptible to the tested enterocins, mainly to Ent7420, EntA(P)/EK13, Ent412, Ent55 and Ent9296 (in the range 100 - 12,800 AU/mL). The most susceptible strains appeared to be the mecA gene-positive S. epidermidis SE R44/1 and SE P3/Tr2a strains, inhibited by eight enterocins out of 11 tested (100-200 AU/mL). Only four strains (including mecA gene positive S. epidermidis SE P3/Tr1 and S. vitulinus SV K12PL/1) were resistant to the tested antimicrobial substances. These results indicate that the enterocins used offer a promising option for prevention and treatment of bacterial infection caused by MRS in animals.

A More Positive Culture by Resin-containing Media Usage after Suspicious Arthroscopic Infections in Patients Receiving Antimicrobial Therapy.

Although infections following arthroscopic surgery of cruciate ligament and meniscus are uncommon, they have potentially serious consequences for the graft and articular cartilage. This study aimed to investigate the efficacy of correct sampling and appropriate media, especially resin-containing media, for the detection of infections in patients receiving antibiotics under suspicion of joint infection after arthroscopic anterior cruciate ligament (ACL) and meniscal surgery. In such cases, proper sampling and the use of suitable culture media that cause the neutralization of antibiotics are very effective in isolating microorganisms from the patient samples and positive cultures. In total, 10 patients who had received antibiotics with suspected knee infection after arthroscopic ACL and meniscal surgery were identified after referral to surgeons during a period of 10 months and investigated in this study. The sample collection, culture on various media (i.e., resin-containing culture media), microbiological tests, and antibiotic susceptibility tests were performed in this study. The amplification of the mecA gene using PCR assay was accomplished for methicillin-resistant staphylococcus strains. This study was conducted on 10 patients who underwent arthroscopic procedures and had received antibiotics. Overall, joint fluid and tissue culture were positive in 60% of the patients. The resin-containing media revealed a trend toward increased detection of bacteria. Coagulase-negative staphylococcus strains were the most frequently isolated bacteria in arthroscopic ACL surgery infections. Out of five methicillin-resistant staphylococcus strains, four strains were found that were resistant to cefoxitin and positive-mecA designated as methicillin-resistant strains. Except for one case, the rest of the staphylococcal strains were resistant to methicillin but susceptible to vancomycin. Despite uncommon and low percentage of infections after arthroscopic ACL and meniscal surgery, the results of our study showed that correct sampling, appropriate cultures, especially aerobic and anaerobic resin-containing media, and microbiological testing remained useful and valuable for diagnosing bacterial infections.

Multiple Antimicrobial Resistance in Methicillin-Resistant Staphylococcus sciuri Group Isolates from Wild Ungulates in Spain.

The aim of this study was to investigate the presence of methicillin-resistant Staphylococcus (MRS) strains in non-managed wild ungulates present in a typical Mediterranean forest in Spain. For this purpose, nasal swabs were obtained from 139 animals: 90 wild boar (Sus scrofa), 42 red deer (Cervus elaphus) and 7 fallow deer (Dama dama), which were subsequently pre-enriched in BHI+ NaCl (6.5%) (24 h/37 °C), and then seeded in Columbia blood agar (24 h/37 °C)). The presence of the mecA gene was investigated by PCR, first from the confluent and then from individual colonies. A total of 10 mecA+ colonies were obtained of which only seven showed phenotypic resistance to oxacillin/cefoxitin (methicillin resistance). All MRS strains belonged to the Staphylococcus sciuri group. Methicillin-resistant Staphylococcus aureus (MRSA) was not detected. In addition, a significant number of MRS strains showed resistance to other antimicrobials, mainly β-lactam (7/7), gentamicin (7/7), fusidic acid (6/7) and quinupristin-dalfopristin (6/7), showing an irregular correlation with their coding genes. The genetic profiles grouped the seven strains obtained according to the bacterial species but not in relation to the animal source or the geographical place of origin. The presence of SCCmec type III, common to animals and humans, has been detected in three of the strains obtained. In conclusion, the study reveals that the wild ungulates investigated play a role as potential reservoirs of multi-resistant strains of MRS. Such strains, due to their characteristics, can be easily transferred to other wild or domestic animal species and ultimately to humans through their products.

Epidemiology of purulent-septic infections caused by methicillin-resistant Staphylococcus in the Republic of Moldova

Staphylococcus infections are a major global concern, caused by the annual growth of methicillin-resistant Staphylococcus strains and the emergence of strains resistant to reserve anti-staphylococcal antibiotics. Aim: The aim of the study was to determine the risk factors, the degree of spread of methicillin-resistant Staphylococcus (MRS) strains in health care facilities in the Republic of Moldova, as well as their resistance to antibacterial drugs. Material and methods: The research of the real incidence, epidemiological peculiarities and the degree of sensitivity/resistance of MRS infections to antibiotics was performed based on the descriptive cross-sectional observational epidemiological study, overall being analyzed 10,055 staphylococcal strains. The risk factors and socio-economic impact were determined based on a retrospective case-control study. The research group included 269 patients with bacteriological investigations positive for methicillin-resistant Staphylococcus (MRS), the control group - 159 patients with bacteriological investigations positive for methicillin-sensitive Staphylococcus (MSS). Results: The share of MRS strains among Staphylococcus strains in the Republic of Moldova is on average 35.97%. A higher level of spread of MRS strains is recorded in maternity hospitals - 61.81%, followed by multi-profile health care facilities - 36.32%, slightly lower in rural health care facilities - 22.36%. The prevalence of MRS strains varied depending on the profile of departments and pathological products. Most often, MRS strains were isolated from patients in the departments of surgery, traumatology, orthopedics, resuscitation and intensive care. A high level of MRS was found in blood cultures - 76.11%, and 96.3% of MRS strains isolated from blood proved to be polyresistant.

Epidemiological aspects in trophic ulcers with methicillin-resistant Staphylococcus

Introduction. Trophic ulcer continues to be a major clinical problem, currently having a significant socio-economic impact. The association of microbial infections, especially with antibiotic-resistant bacteria, is one of the most common complications of trophic ulcers. In this context, trophic ulcers associated with methicillin-resistant Staphylococcus (MRS) have a high epidemiological and clinical significance. &#x0D; Material and methods. The determination of risk factors, antimicrobial resistance, as well as the clinical and socio-economic impact of trophic ulcers caused by MRS strains was performed based on a retrospective case-control study. The research group included 52 observation sheets of patients with trophic ulcers caused by methicillin-resistant Staphylococcus (MRS), the control group - 39 sheets of patients with trophic ulcers caused by methicillin-sensitive Staphylococcus (MSS). &#x0D; Results. MRS strains isolated from trophic ulcers had high rates of antibiotic resistance compared to MSS strains. As a risk factors of trophic ulcer from which MRS strains have been isolated, people over the age of 50, repeated hospitalizations, microbial associations and exposure to intensive care are highlighted.&#x0D; Conclusions. Risk factors and local epidemiology knowledge in trophic ulcers with MRS is the key factor in implementing and complying with surveillance and control measures.

Monitoring Methicillin-Resistant Staphylococcus Strains in the Moscow Medical and Surgical Center using Molecular-Biological Methods

Relevance. Staphylococci are one of the most common pathogens in the etiological structure of nosocomial infections. Methicillinresistant staphylococci are resistant to the main groups of antibiotics and are one of bacteria that pose the greatest threat to human health according to the World Health Organization. The introduction of modern molecular biological methods in the monitoring of methicillin-resistant staphylococci is necessary for the rapid and accurate identification of microorganisms, monitoring the epidemiological situation and studying the need for anti-epidemic measures. Aims. Аnalysis of the results of monitoring methicillinresistant staphylococcus strains using molecular biological methods in a multidisciplinary hospital in Moscow for one year. Materials and methods. Single-center observational study with a one-year follow-up period (December 2016 to December 2017). The research included a molecular-biological analysis of biological material from 240 patients with signs of infection and washings samples (n=250) from the objects of the hospital environment. The whole genome sequencing was carried out for 24 samples, isolated from patients with different forms of staphylococcal infection and washings from a hospital environment. DNA detection of methicillin-resistant strains was performed using the «AmpliSens®MRSA-screen-titer-FL» reagent kit. Sequencing was performed on an Illumina HiSeq1500 instrument using the IlluminaHiSeq PE RapidClusterKit v2 and IlluminaHiSeqRapid SBS Kit v2. Results. DNA of methicillin-resistant staphylococci were detected in 6.3% of blood samples from patients with signs of infection and in 42.4% of washings from the objects of the hospital environment. The results of PCR of washing samples showed that DNA of methicillin-resistant coagulase-negative staphylococci were detected much more often than MRSA (p &lt;0.001). DNA of methicillin-resistant staphylococci were detected more often in the intensive care and intensive care units compared with the hematology and surgical departments (p &lt;0.001). The examine samples of Staphylococcus aureus belonged to 6 different sequence types (ST-5, ST-7, ST-8, ST-22, ST-30 and ST-5555) and 8 spatypes (t008, t021, t091, t1062, t12437, t1544, t223, t4573). As a result of monitoring, an isolate with a new allelic profile was found. Today it has been assigned the number ST5555. The predominant type of staphylococcal mec cassette was the type IV SCCmec cassette. Conclusion. Due to the widespread distribution of methicillin-resistant strains and the identification of epidemiologically significant genetic lines of staphylococci, it is necessary to conduct regular monitoring, take measures to limit the spread of such strains and introduce modern molecular biological methods for quick and accurate identification.

New acridine derivatives as promising agents against methicillin-resistant staphylococci – From tests to in silico analysis

The present study describes the antibacterial activity of several new derivatives of tacrine or cyclopentaquinoline bound to either 6-hydrazinenicotinic acid or 4-fluorobenzoic acid through an aliphatic chain against methicillin-resistant staphylococcal strains. All derivatives showed antibacterial activity against all tested methicillin-resistant staphylococci. Of these, compounds 6, 18, 23 and 24 exhibited the highest activity, ranging from 4.87 to 19.5 μg/mL MBC (Minimum Bactericidal Concentration) depending on the bacterial strain. These values were not much greater than that for vancomycin, the reference standard for the treatment of methicillin-resistant Staphylococci infections in humans. In addition, all synthesized compounds underwent a quantitative structure-activity relationship analysis. Correlation and multicollinearity tests were used to select descriptors as independent variables for multiple linear regression models to quantify the relationships between biological activity and the structural parameters.