Dose regimen optimization of cephalothin for surgical prophylaxis against Staphylococcus aureus and coagulase negative staphylococci in dogs by pharmacokinetic/pharmacodynamic modeling.

First generation cephalosporins such cephalothin of cefazolin are indicated for antimicrobial prophylaxis for clean and clean contaminated surgical procedures because its antimicrobial spectrum, relative low toxicity and cost. Anesthesia and surgery could alter the pharmacokinetic behavior of different drugs administered perioperative by many mechanisms that affect distribution, metabolism or excretion processes. Intravenous administration of the antimicrobial within 30 and 60 min before incision is recommended in order to reach therapeutic serum and tissue concentrations and redosing is recommended if the duration of the procedure exceeds two half-life of the antimicrobial. To the author's knowledge there are no pharmacokinetic studies of cephalothin in dogs under anesthesia/surgery conditions. The aim of this study was (1) to evaluate the pharmacokinetics of cephalothin in anesthetized dogs undergoing ovariohysterectomy by a nonlinear mixed-effects model and to determine the effect of anesthesia/surgery and other individual covariates on its pharmacokinetic behavior; (2) to determine the MIC and conduct a pharmacodynamic modeling of time kill curves assay of cephalothin against isolates of Staphylococcus spp. isolated from the skin of dogs; (3) to conduct a PK/PD analysis by integration of the obtained nonlinear mixed-effects models in order to evaluate the antimicrobial effect of changing concentrations on simulated bacterial count; and (4) to determine the PK/PD endpoints and PK/PDco values in order to predict the optimal dose regimen of cephalothin for antimicrobial prophylaxis in dogs. Anesthesia/surgery significantly reduced cephalothin clearance by 18.78%. Based on the results of this study, a cephalothin dose regimen of 25 mg/kg q6h by intravenous administration showed to be effective against Staphylococcus spp. isolates with MIC values ≤2 µg/mL and could be recommended for antimicrobial prophylaxis for clean surgery in healthy dogs.

Does Topical Vancomycin Powder Use in Fracture Surgery Change Bacteriology and Antibiotic Susceptibilities? An Analysis of the VANCO Trial.

OBJECTIVE: To determine whether intrawound vancomycin changes the bacteriology of surgical site infection pathogens and investigate the emergence of antibiotic-resistant pathogens. DESIGN: Secondary analysis of phase III, prospective, randomized clinical trial. SETTING: Thirty-six US trauma centers. PATIENT SELECTION CRITERIA: Patients who became infected after fixation of tibial plateau or pilon fracture. OUTCOME MEASURES AND COMPARISONS: Pathogen types and bacterial susceptibilities as determined from routine clinical culture in the operating room. RESULTS: Seventy-four patients were studied who were 67.5% male with a mean age of 48.6 years. A lower proportion of gram-positive cocci was observed in the vancomycin powder compared with the standard-of-care group (3.7% vs. 8.0%, P = 0.01). Methicillin-resistant Staphylococcus aureus infection incidence was comparable in both the vancomycin powder and the standard-of-care groups, but rates of methicillin-susceptible S. aureus infections were lower in the treatment group (1.4% vs. 4.8%, P = 0.01). The incidence of coagulase-negative Staphylococci and gram-negative rod infections were similar in both groups. There was no significant difference in susceptibilities between groups in rates of vancomycin-resistant enterococcus. CONCLUSIONS: Topical vancomycin powder decreases the likelihood of gram-positive infections consistent with the biologic activity of vancomycin. Fewer methicillin-susceptible S. aureus and coagulase-negative Staphylococci infections were observed in the group treated with vancomycin powder. An effect of vancomycin powder on methicillin-resistant S. aureus infection risk was not detected given the low incidence in both the intrawound vancomycin and the standard-of-care groups. There was no emergence of gram-negative rod infections or increased resistance patterns observed. Use of topical vancomycin powder does not seem to produce infections in these patients with greater antibiotic resistance than would have occurred without its use. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Evaluation of Latex Agglutination Test for Rapid Identification of Staphylococcus aureus Isolated from Pyogenic Wound Infections at a Tertiary Care Hospital.

Background Staphylococcus aureus infections are increasingly reported worldwide. It is a major clinical problem and imposes significant morbidity and mortality due to widespread emergence of multidrug resistant pathogens like methicillin resistant Staphylococcus aureus. Thus, rapid and reliable identification of Staphylococcus aureus is essential for timely and effective management of patient. Objective The performance of Latex agglutination test (Staphaurex Plus) was compared to conventional method tube coagulase test which is gold standard too for the identification of Staphylococcus aureus. Method This study was conducted at B.P. Koirala Institute of Health Sciences. Following standard microbiological methods, isolation and identification was done in the Department of Microbiology. MRSA detection was performed following Clinical and Laboratory Standard Institute. All the isolates of Staphylococci were subjected for Latex agglutination test and was performed according to manufacturer's instructions using Staphaurex Plus kit. Result Out of 377 (methicillin sensitive Staphylococcus aureus - 142; methicillin resistant Staphylococcus aureus - 233; Coagulase Negative Staphylococci -2) isolates of Staphylococci, Latex agglutination test was found to be positive in 138 (97.1%) of methicillin sensitive Staphylococcus aureus (MSSA) and 220 (94.4%) of methicillin resistant Staphylococcus aureus (MRSA). Overall sensitivity, specificity, positive predictive value and negative predictive value of Latex agglutination test was found to be 95.46%, 100%, 100%, 10.52% respectively. Conclusion In conclusion, Latex agglutination test is a rapid and reliable test for the identification of Staphylococcus aureus.

Bilobetin attenuates Staphylococcus aureus virulence by targeting Von Willebrand factor-binding protein and staphylocoagulase.

Staphylococcus aureus (S. aureus) induces a variety of infectious diseases in humans and animals and is responsible for hospital- and community-acquired infections. The aim of this study was to investigate how bilobetin, a natural compound, attenuates S. aureus virulence by inhibiting two key virulence factors, von Willebrand factor-binding protein (vWbp) and staphylocoagulase (Coa). The results showed that bilobetin inhibited Coa- or vWbp-induced coagulation without affecting S. aureus proliferation. The Western blotting and fluorescence quenching assays indicated that bilobetin did not affect the expression of vWbp and Coa but directly bound to the proteins with KA values of 1.66 × 104 L/mol and 1.04 × 104 L/mol, respectively. To gain further insight into the mechanism of interaction of bilobetin with these virulence factors, we performed molecular docking and point mutation assays, which indicated that the TYR-6 and TYR-18 residues on vWbp and the ALA-190 and ASP-189 residues on Coa were essential for the binding of bilobetin. In addition, the in vivo studies showed that bilobetin ameliorated lung tissue damage and inflammation caused by S. aureus, thereby improving the survival of mice. Furthermore, the use of bilobetin as an adjuvant in combination with vancomycin was more effective in the treatment of a mouse model of pneumonia. Taken together, bilobetin had a dual inhibitory effect on vWbp and Coa by reducing the virulence of S. aureus, suggesting that it is a viable lead compound against S. aureus infections.

Inhibitory Effect of Salicin on Staphylococcus aureus Coagulase.

The massive use of antibiotics has resulted in an alarming increase in antibiotic resistance in Staphylococcus aureus (S. aureus). This study aimed to identify the inhibitory effect of salicin on S. aureus. Coagulase (Coa) activity was assessed using in vitro Coa assays and Western blot, thermal shift assay (TSA), fluorescence quenching and molecular docking experiments were conducted to verify the interaction between salicin and Coa. An in vivo mouse pneumonia model demonstrated that salicin can reduce the virulence of S. aureus. In vitro Coa assays elucidated that salicin directly inhibited Coa activity. The Western blot and TSA results suggested that salicin did not block the expression of Coa but affected the thermal stability of the protein by binding to Coa. The fluorescence quenching, molecular docking and molecular dynamics assays have found that the most promising binding site between salicin and Coa was GLN-97. The pneumonia model of mice infected with S. aureus revealed that salicin could not only reduce the content of lung bacteria in mice but also prolong their survival. Salicin was identified as a novel anti-infective candidate compound with the potential to target Coa and inhibit its activity by binding to it, which would facilitate the development of roadmaps for future research.

The Efficacy of Bacteriocins Against Biofilm-Producing Bacteria Causing Bovine Clinical Mastitis in Dairy Farms: A New Strategy.

Using an alternative bio-product is one of the most promising ways to control bovine mastitis and avoid new intra-mammary infections. The aims of this study were to ascertain the prevalence of biofilm-forming bacteria responsible for causing clinical mastitis in dairy herds and to assess the effectiveness of bacteriocins, produced by Bacillus subtilis, in controlling the growth of these bacteria in the milk of animals. A total of 150 milk samples were collected from cows and buffalos suffering from mastitis and the etiological agents were isolated and identified by the VITEK-2-COMPACT-SYSTEM®. Additionally, the capability of the bacterial isolates to produce biofilms was determined. RT-PCR was used to detect enterotoxin-producing genes (sed and seb), resistance genes (mecA and blaZ), and biofilm-associated genes (icaA and fnbA) in the isolated bacteria. The susceptibility patterns of the bacterial isolates to bacteriocins were assessed using an agar well-diffusion assay. S. aureus was significantly more capable of producing biofilms than coagulase-negative Staphylococcus isolates. S. ubris was the strongest biofilm producer among the Streptococcus species. The sensitivity profiles of the Staphylococcus spp. (S. aureus and coagulase-negative Staphylococcus) and their biofilm producers to bacteriocins were significantly higher (100% and 90%, respectively) at the same concentration. Bacteriocins had a lethal effect on Staphylococci, Streptococci, and biofilm development at a dose of 250 µg/mL. In dairy farms, bacteriocins are a viable alternative treatment for the prevention and control of bovine clinical mastitis.

Bacterial colonisation and the effect of a cleaning regime on iPad patient side electronic devices used in a veterinary healthcare setting.

OBJECTIVES: This study aimed to determine the prevalence of clinically relevant bacteria on the surface of hospital-issued iPads and to assess the effectiveness and residual effect of a new cleaning regime using 70% alcohol and 2% chlorhexidine wipes. METHODS: Hospital-issued iPads were swabbed to determine the presence of clinically relevant organisms. The iPads were wiped using 70% alcohol and 2% chlorhexidine. Further samples were taken 5 mins, 6 h and 12 h after implementation of the cleaning regime. Cultured bacteria were tested for antimicrobial resistance. RESULTS: A total of 25 hospital-issued iPads were analysed. Seventeen iPads (68%) sampled in this study were contaminated. Bacillus species (21%) were the most predominant, followed by Pasteurella species (14%), Acinetobacter species (11%), Eikenella species (11%), beta-haemolytic streptococci (11%), coagulase-positive staphylococci (7%), Escherichia coli (7%), coagulase-negative staphylococci (7%), alpha-haemolytic streptococci (3%), Enterococcus species (4%) and Pseudomonas species (4%). Of the isolated bacteria, 89% were resistant to at least one of the tested antibiotics. Of our isolates, 24 (75%) were resistant to clindamycin. After the cleaning regime, there was no bacterial growth from any of the devices at 5 mins, 6 h and 12 h despite repetitive use within the hospital. CONCLUSIONS AND RELEVANCE: A variety of nosocomial pathogens, including antibiotic resistant pathogens, were isolated from the iPads. Cleaning with 70% alcohol and 2% chlorhexidine wipes is recommended every 12 h during use, between patient contacts and after witnessed contamination. A variety of nosocomial pathogens, including antibiotic-resistant pathogens with potential devastating effects on both human and animal health, were isolated from the iPads. Infection prevention strategies related to the devices should be employed in a hospital setting.

Population pharmacokinetics and pharmacokinetic/pharmacodynamic evaluation of marbofloxacin against Coagulase-negative staphylococci, Staphylococcus aureus and Mycoplasma agalactiae pathogens in goats.

Marbofloxacin is a broad-spectrum fluoroquinolone, and an extra-label use has been reported in horse, sheep and goat. However, extrapolation of dosage regimens from cattle to horse and small ruminants could lead to incorrect dosing due to pharmacokinetic differences among species, increasing the risk of antimicrobial resistance or toxicity. Pharmacokinetic properties of marbofloxacin, including PK/PD analysis, have been studied by intravenous, intramuscular and subcutaneous administration in lactating and non-lactating goats. A population pharmacokinetic model of marbofloxacin in goats was built using 10 pharmacokinetic studies after intravenous, intramuscular, and subcutaneous administration at a dose of 2, 5 and 10 mg/kg. Serum or plasma and milk concentration-time profiles were simultaneously fitted with a non-linear mixed effect model with Monolix software. Level of milk production (lactating and non-lactating) and health status (healthy and un-healthy) were retained as covariates on volume of distribution and clearance. Marbofloxacin concentrations were well described in plasma/serum and milk by the population model. Simulated dose regimens of marbofloxacin administered at 2, 5 and 10 mg/kg by intramuscular route for five days were evaluated (n = 5000 per group). Steady-state fAUCs for each dose regimen were obtained. Probability of target attainment of fAUC/MIC ratios were determined and PK/PDco values (highest MIC for which 90% of individuals can achieve a prior numerical value of the fAUC/MIC index) were established using Monte Carlo simulations (n = 50,000). MIC values for wild type isolates of Staphylococcus aureus, coagulase negative staphylococci, and Mycoplasma agalactiae were determined and tentative epidemiological cutoff (TECOFF) were obtained at 1.0, 0.5 and 0.5 mg/L, respectively. The PK/PDco for the dose regimen of 2 mg/kg/24 h and 5 mg/kg/24 h (0.125 and 0.25 mg/L) were lower than TECOFF (0.5 and 1 mg/L). The dosage regimen of 10 mg/kg/24 h was adequate for intermediate MIC values of 0.125-0.50 mg/L and could be effective for a population with a target fAUC/MIC ratio ˂ 48 for Coagulase negative staphylococci and Mycoplasma agalactiae, but not for Staphylococcus aureus. Results obtained in this study could be taken as a starting point by committees that set the clinical breakpoints and justifies expert rules to optimize marbofloxacin dose regimens.

Effects of the Dibenzofuran, Usnic Acid, on Inhibition of Ocular Biofilm Formation Due to Coagulase-Negative Staphylococci.

BACKGROUND Coagulase-negative staphylococci (CoNS) are gram-positive, aerobic, commensal bacteria found on the skin and mucus membranes, including the conjunctiva. Usnic acid (UA) is a dibenzofuran derivative isolated from lichens. This study aimed to investigate the effects of usnic acid on inhibition of ocular biofilm formation due to CoNS. MATERIAL AND METHODS Nine Staphylococcus epidermidis isolates, 5 Staphylococcus hominis isolates, 2 Staphylococcus saprophyticus isolates, and 1 Staphylococcus capitis and Staphylococcus lentus isolates were taken as test bacteria. They were inoculated into brain heart infusion broth and incubated for 24 hours at 35°C and activated. Antibiotic susceptibility was investigated by Kirby-Bauer disc diffusion method. Biofilm production was determined using the microtiter plate method and optical densitometry was measured at 570 nm using an automated microplate reader. Anti-biofilm activity of UA was determined by microtitration method and biofilm removal percentage was calculated. RESULTS All tested bacteria were found as high biofilm-producer strains; they were generally resistant to methicillin, but susceptible to vancomycin. UA inhibited the biofilm formation of S. epidermidis isolates, ranging from 5.7% to 81.5%. It inhibited the biofilm formation of S. saprophyticus and S. lentus by 73.3% and 74.3%, respectively. There was no effect of UA on mature biofilms of S. epidermidis 17.7H, S. epidermidis 15.41, S. hominis 9.3, S. hominis 17.2H, S. saprophyticus, and S. lentus. CONCLUSIONS It was determined that UA exerted anti-biofilm activity on some CoNS isolated from the ocular surface. Anti-biofilm activity was found to be higher even in strains that did not show antibacterial activity.

Analysis of pathogen distribution and antimicrobial resistance at infected sites in plastic surgery.

OBJECTIVE: By analyzing the distribution and drug resistance of common pathogen in different sites in plastic surgery to provide reference for clinicians to choose the best antibacterial treatment plan. METHODS: Pathogens of postoperative infection in plastic surgery from January 2011 to December 2021 were retrospectively analyzed to determine the species and quantity, and to access the trend of each pathogen's detection rate. The antibiotic sensitivity and distribution characteristics of common pathogens were studied in conjunction with the site of infection. RESULTS: A total of 1709 bacterial strains were detected, including 1244 gram-positive bacterial strains and 465 gram-negative bacterial strains. The main pathogen of perineum was Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa), while Staphylococcus aureus (S. aureus) was the most common pathogen in the other infected sites. The detection rate of methicillin-resistant S. aureus (MRSA) and methicillin-resistant coagulase-negative staphylococcus (MRCNS) was on the rise from 2011 to 2021. No S. aureus and coagulase-negative staphylococcus (CoNS) strains were resistant to vancomycin. The sensitive rate of S. aureus from all parts and CoNS from all sites except lower limbs and mandible was higher than 80% to linezolid. The resistance rate of S. aureus and CoNS in all parts to penicillin, clindamycin, and erythromycin was high. The susceptibility rate of CoNS in lower mandible was high to gentamicin. CONCLUSIONS: Staphylococcus aureus was the primary pathogen of gram-positive bacteria in all site of plastic surgery except perineum, followed by CoNS. The distribution and drug resistance of pathogen in different infection sites were different. We should formulate more accurate and reasonable antibacterial programs according to drug resistance results of various parts to reduce the emergence of resistant strains and effectively prevent and control infection.

Comparative Genotypic Analysis of RAPD and RFLP Markers for Molecular Variation Detection of Methicillin-Resistant Staphylococcus aureus Clinical Isolates.

Background and Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) isolates are associated with various diseases ranged from mild superficial impairments to invasive infections. This study aimed to evaluate the ability of polymerase chain reaction (PCR) based methods namely, restriction fragment length polymorphism (RFLP) of the coa gene and random amplified polymorphic DNA (RAPD), to determine the genetic diversity of MRSA isolates. Materials and Methods: A total of 37 MRSA isolates were conventionally identified depending on their biochemical and microbiological culture characteristics. Genotypic confirmation was based on detection of the associated mecA gene. The genetic variation amongst MRSA isolates was evaluated following the coa gene-based RFLP and RAPD fingerprints. Results: Results illustrated that, the species specific coa gene was detected in all MRSA isolates. The irregular bands intensity, number, and molecular sizes of the PCR amplicons demonstrated the coa gene polymorphism. The incompatible AluI digestion patterns of these amplicons classified the tested MRSA isolates into 20 RFLP patterns which confirm the coa gene polymorphism. Additionally, the PCR-based RAPD analysis showed variable bands number with size range of approximately 130 bp to 4 kbp, which indicated the genetic variation of the tested MRSA isolates as it created 36 variable RAPD banding profiles. Conclusions: coa gene AluI enzymatic restriction sites, amongst the tested MRSA isolates, certify their genetic variation on the basis of the accurate but complicated and relatively expensive coa gene-based RFLP. Conversely, the results verified the excellent ability of the simple and cost-effective PCR-based RAPD analysis to discriminate between MRSA isolates without any preface data about the genome.

A vancomycin resistance-associated WalK(S221P) mutation attenuates the virulence of vancomycin-intermediate Staphylococcus aureus.

INTRODUCTION: Vancomycin-intermediate Staphylococcus aureus (VISA) is typically associated with a decline in virulence. We previously reported a WalK(S221P) mutation that plays an important role in mediating vancomycin resistance in VISA XN108. Whether this mutation is implicated in bacterial virulence remains unknown. OBJECTIVES: This study aimed to investigate the effect of WalK(S221P) mutation on the virulence of VISA and the underlying mechanism of this effect. METHODS: The influence of WalK(S221P) mutation on VISA virulence and its underlying mechanism were explored using animal models, RNA-seq analysis, RT-qPCR, hemolytic assay, slide coagulase test, Western blot, ß-galactosidase assay, and electrophoresis mobility shift assay (EMSA). RESULTS: Compared with XN108, WalK(S221P)-reverted strain XN108-R exacerbated cutaneous infections with increased lesion size and extensive inflammatory infiltration in mouse models. The bacterial loads of S. aureus XN108-R in murine kidney increased compared with those of XN108. RNA-seq analysis showed upregulation of a set of virulence genes in XN108-R, which exhibited greater hemolytic and stronger coagulase activities compared with XN108. Introduction of WalK(S221P) to methicillin-resistant S. aureus USA300 and methicillin-susceptible strain Newman increased the vancomycin resistance of the mutants, which exhibited reduced hemolytic activities and decreased expression levels of many virulence factors compared with their progenitors. WalK(S221P) mutation weakened agr promoter-controlled ß-galactosidase activity. EMSA results showed that WalK-phosphorylated WalR could directly bind to the agr promoter region, whereas WalK(S221P)-activated WalR reduced binding to the target promoter. Inactivation of agr in S. aureus did not affect their vancomycin susceptibility but mitigated the virulence alterations caused by WalK(S221P) mutation. CONCLUSION: The results of our study indicate that WalK(S221P) mutation can enhance vancomycin resistance in S. aureus of diverse genetic backgrounds. WalK(S221P)- bearing S. aureus strains exhibit reduced virulence. WalK(S221P) mutation may directly impair the activation of the agr system by WalR, thereby decreasing the expression of virulence factors in VISA.

[Investigation of Biofilm Formation Properties of Coagulase Negative Staphylococci Isolated from Catheter-Related Bloodstream Infections]. / Kateter Iliskili Kan Dolasimi Enfeksiyonlarindan Izole Edilen Koagülaz Negatif Stafilokoklarin Biyofilm Olusturma Özelliklerinin Arastirilmasi.

In view of the significant negative impact of biofilm-mediated infection on patient health and the necessity of a reliable phenotypic method to detect biofilm producers, this study aimed to demonstrate phenotypic and molecular biofilm formation in coagulase-negative staphylococci (CoNS) isolated from catheter related infections and to compare the methods used with each other. The study was also aimed to determine the biofilm eradication effect of vancomycin in order to guide for the treatment. For the detection of biofilm formation, a total of 154 CoNS clinical isolates of which 30 being causative agents of catheter related bloodstream infection (CRBSI) (isolated from both the catheter tip and blood cultures of 15 patients), 89 being isolated from peripheral blood cultures of patients without a central venous catheter (CVC) (13 of them were bloodstream infection agents, 76 of them were contaminant), and 35 being isolated as catheter colonizer, were screened by tissue culture plate (TCP), Congo red agar (CRA) method and polymerase chain reaction (icaA, icaD and IS256). Vancomycin minimum inhibitory concentration (MIC) and minimum biofilm eradicating concentration (MBEC) values were determined. The pulsed field gel electrophoresis (PFGE) method was used to show the clonal relationship between CoNS isolated from the catheter tips and peripheral blood of patients with CRBSI. Of the 154 CoNS isolates included in the study, 38.9% were Staphylococcus epidermidis (n= 60), 34.4% were Staphylococcus haemolyticus (n= 53), 20.7% were Staphylococcus hominis (n= 32), and 3.8% were detected as Staphylococcus capitis (n= 6). In our study, biofilm formation was shown in 31.8% with the CRA method and in 68.1% with the TCP method. By TCP method, 22% (n= 34) were determined as weak, 31.2% (n= 48) medium and 14.9% (n= 23) strong biofilm producers. While the sensitivity of the CRA method was found to be low for isolates that were determined as weak positive in the microplate method, the high sensitivity of the CRA method for isolates with medium and strong positivity was found remarkable. The positivity rates of icaA, icaD and IS256 genes in a total of 154 CoNS isolates were found to be 40 (25.9%), 57 (37%) and 77 (50%), respectively. In total, at least one gene positivity was detected in 107 (69.5%) isolates. Single gene positivity was detected in 55 (35.7%), two gene positivity in 35 (22.7%) and three gene positivity was detected in 17 (11%) of the included CoNS. Biofilm formation (four weak, four medium, two strong) was detected by microplate method in 10 of 47 CoNS isolates (five S.epidermidis, three S.hominis, one S.haemolyticus and one S.capitis) in which no genes were detected. Vancomycin MBEC/ MIC values were found to be high and it was observed that as the biofilm forming power of the isolates increased, the MBEC/MIC ratio also increased. The CoNS isolated from the catheter samples and blood of patients diagnosed with CRBSI had a 100% similar profile with PFGE except for one unevaluable isolate. The tissue culture plate (TCP) method was found to be most sensitive, accurate and reproducible screening method for detection of biofilm formation by staphylococci and has the advantage of being a quantitative model to study the adherence of staphylococci. The presence of the icaAD and IS256 gene is not always associated with in vitro biofilm formation. For this reason, it is more appropriate to use more than one method together for the evaluation of biofilm formation. It was thought that the use of reliable methods to specifically detect biofilms could be helpful in diseases that are difficult to treat. Considering the high rates of biofilm and antimicrobial resistance of biofilm-forming isolates in biomedical device associated infections, it was determined that it would not be sufficient to evaluate only the MIC results for susceptibility results.

The production and influence of anti-Vibrio parahaemolytics IgY against experimental infection of V. parahaemolyticus in cultured Fenneropenaeus indicus.

The increasing number of antibiotic-resistant bacteria emphasizes the need to find alternatives to complement antibiotics. Immunotherapy may also be used as a complementary treatment against pathogens that are difficult to treat with traditional antibiotics. Eggs are normal dietary components and there is practically no risk of toxic side effects of IgY given orally. In the present study, pathogenic Vibrio parahaemolyticus was isolated from infected shrimp and studied their virulence factors including LD50 (by challenging with Fenneropenaeus indicus), proteolytic and hemolytic activities. The edible antibody IgY was raised by injecting the antigen of Extra Cellular Products (ECP) of V. parahaemolyticus to Gallus gallus domesticus during layoff period with and without the herbal immunoadjuvants, Asparagus racemosus and Glycine max (V.p wo: V. parahaemolyticus ECP without adjuvant; V.p A: V. parahaemolyticus ECP with A. racemosus and V.p G: V. parahaemolyticus ECP with G. max). Eggs were collected after five weeks of immunization and anti- V. parahaemolyticus IgY was extracted and purified. Physicochemical properties of the immunized Chickens' serum and anti- V. parahaemolyticus IgY's cross reactivity, growth inhibition assay, single radial immunodiffusion assay and bacterial agglutination were studied. The results revealed that, the serum protein parameters were significantly (P ≤ 0.001) increased in experimental groups from control group. The antibody raised with immunoadjuvants had significantly (P ≤ 0.001) higher cross reactivity, growth inhibition, single radial immunoassay and bacterial agglutination when compared with and without immunoadjuvant and control groups. Further the control and experimental anti-V. parahaemolytics IgY coated artificial diets were fed to F. indicus for 60 days. After 30 and 60 dpv (days of post vaccination), shrimps from each groups were challenged with virulent V. parahaemolyticus and studied the survival, haematological and immunological parameters. The IgY coated diets (V. p A and V.p G) fed shrimps had decreased cumulative mortality, significantly (P ≤ 0.001) improved coagulase activity, total haemocyte count and oxyhaemocyanin. The immunological parameters such as prophenoloxidase, intracellular anion production, lysozyme production and phagocytosis also improved significantly (P ≤ 0.001) in IgY treated shrimps.

Optimal exposure targets for vancomycin in the treatment of neonatal coagulase-negative Staphylococcus infection: A retrospective study based on electronic medical records.

BACKGROUND: The currently advocated ratio of area under the curve (AUC) over 24 h to minimum inhibitory concentration (AUC/MIC) > 400 and AUC < 600 mg h/L as the therapeutic drug monitoring (TDM) target of vancomycin is based on data from multiple observational studies in adult patients with methicillin-resistant Staphylococcus aureus (MRSA) infection. It may not be applicable to newborns with coagulase-negative Staphylococcus (CoNS) infection. We conducted a retrospective study to identify the optimal exposure targets for vancomycin in the treatment of neonatal CoNS infection. METHODS: Based on the inclusion and exclusion criteria, serum vancomycin concentration, demographics, clinical data, and related laboratory data of newborns who received vancomycin intravenous infusion from June 1, 2016 to February 1, 2021 were collected retrospectively. The AUC was calculated using the maximum a posteriori Bayesian (MAPB) method. The vancomycin exposure threshold of AUC/MIC for efficacy and AUC for toxicity (acute kidney injury, AKI) were determined based on receiver operating characteristic (ROC) curve analysis. The correlation between vancomycin exposure and both clinical effect and nephrotoxicity was analyzed using logistic multivariate regression. RESULTS: In total, 153 patients and 245 vancomycin concentrations (160 trough and 85 peak concentrations) were included. The ROC curve analysis showed that the exposure thresholds of AUC/MIC for clinical efficacy and AUC for nephrotoxicity were 281 and 602 mg h/L, respectively. The multivariate regression analysis showed that AUC/MIC > 280 was a predictor of efficacy (OR: 13.960, 95% CI: 1.891-103.078, P < 0.05) and AUC > 600 mg h/L was associated with AKI (OR: 9.008, 95% CI: 2.706-29.983, P < 0.05). The vancomycin AUC/MIC threshold for treating neonatal CoNS infection with vancomycin is lower than the currently advocated AUC/MIC >400. CONCLUSION: The optimal exposure targets for vancomycin in neonatal CoNS infection were AUC/MIC > 280 and AUC < 600 mg h/L.

Use of photodynamic therapy and photobiomodulation as alternatives for microbial control on clinical and subclinical mastitis in sheep.

Evaluate the effects of antimicrobial photodynamic therapy (aPDT) and photobiomodulation (PBM) as alternatives in the treatment of mastitis in sheep. A total of 100 sheep were evaluated, and four teats with clinical mastitis and 16 teats with subclinical mastitis were selected. Milk was collected for isolation and identification of microorganisms. They were grown on TSA, EMB, and MacConkey agar for 24 h, and the microorganisms were identified by Gram stain and biochemical tests. The ceilings were subdivided into four groups: G1, treatment with photosensitizer; G2, treatment with PBM (diode laser λ = 660 nm); G3, aPDT with methylene blue, and G4, control group. Milk samples were collected before, 24 and 48 h after treatments. Cases of subclinical mastitis presented coagulase-negative Staphylococcus and Streptococcus spp, and clinical mastitis had Escherichia coli grow from the samples. The treatments decrease the total bacterial count of negative coagulase Staphylococcus, Streptococcus spp, and Escherichia coli. Comparing the treatments, aPDT stood out, as it was able to photoinactivate all bacteria. Treatment with methylene blue photosensitizer, PBM, and aPDT induced the initial microbial reduction, but aPDT was more effective 48 h after treatment.

Aptamer RA36 inhibits of human, rabbit, and rat plasma coagulation activated with thrombin or snake venom coagulases.

RA36 DNA aptamer is a direct anticoagulant prolonging clotting time of human, rabbit, and rat plasma in the thrombin time test. Anticoagulant activity of RA36 is lower than that of recombinant hirudin. During inhibition of human plasma clotting activated with echitox (coagulase from Echis multisquamatus venom), the aptamer presumably binds to meisothrombin exosite I. The sensitivity of human plasma to the aptamer 5-fold surpasses that of rat plasma. Analysis of RA36 binding to coagulase of Agkistrodon halys venom (ancistron) is required for proving the effect of aptamer on polymerization of human fibrinogen.

Bacteriemias por Staphylococcus coagulasa negativa: análisis de factores pronóstico e influencia del tratamiento antibiótico / Coagulase-negative Staphylococcus bacteraemia: prognosis factors and influence of antibiotic treatment

Introducción: Staphylococcus coagulasa negativa (SCN) es el microorganismo que se aisla con mayor frecuencia en los hemocultivos (HC) obtenidos en pacientes hospitalizados; su pronóstico se ha asociado a la gravedad clínica del paciente así como a un tratamiento antibiótico empírico inadecuado pero en la actualidad la influencia del tratamiento antibiótico empírico adecuado en la supervivencia de los enfermos no representa un factor pronóstico claramente reconocido. Los objetivos del estudio fueron analizar los factores asociados a una mayor mortalidad en pacientes con bacteriemia por SCN y la influencia del tratamiento antibiótico empírico en su evolución. Pacientes y método: análisis prospectivo (enero a junio de 2010) de los pacientes con HC positivos para SCN en un centro hospitalario universitario; se clasificó la bacteriemia como verdadera atendiendo a criterios de los CDC y se evaluaron los parámetros epidemiológicos, clínicos y microbiológicos relacionados con el fallecimiento del paciente. Resultados: se incluyeron 269 casos en el estudio (97 bacteriemias verdaderas); el 92% de los pacientes evolucionó hacia la curación y el 8% fallecieron (el 1,6% de los fallecimientos se consideró relacionado con la bacteriemia por SCN). Staphylococcus epidermidis fue el SCN identificado con más frecuencia. En el estudio de mortalidad relacionada se incluyeron 93 casos de bacteriemia verdadera. Se asociaron de forma estadísticamente significativa al fallecimiento de los pacientes (estudio bivariante) la gravedad clínica del enfermo (Winston I-III), el ser portador de marcapasos, el desarrollo de sepsis o endocarditis infecciosa y la bacteriemia persistente. El tratamiento empírico adecuado no se asoció a una mayor supervivencia. Conclusiones: el pronóstico de los enfermos con bacteriemia por SCN se asocia a la gravedad y las complicaciones sépticas desarrolladas, siendo mayor en pacientes portadores de marcapasos; en nuestra experiencia el tratamiento empírico inadecuado no se asocia a mortalidad(AU)

Introduction: Coagulase-negative staphylococci (CNS) are the most frequent isolated microorganism in blood cultures; mortality has been associated to severity and to adequacy of empirical treatment but the relevance of the latter is not clearly recognised. The aims of the study were to analyze clinical and microbiological factors related to mortality in patients with CNS bacteraemia and the influence of empirical treatment in prognosis. Patients and methods: a prospective cohort study of patients with CNS bacteraemia was performed (January to June 2010) at a university-affiliated hospital; a determination of clinical significance was made and true bacteraemia was defined according to CDC criteria. We analysed epidemiological, clinical and microbiological variables related to mortality. Results: a total of 269 cases were included (97 were considered true bacteraemia); 92% survived and mortality was 8% (1.6% CNS bacteraemia related mortality). Staphylococcus epidermidis was the most frequent isolated species; 93 patients were included in the related mortality study of patients with true bacteraemia. Factors associated to mortality in the bivariate analysis (p<0.05) were: Winton score I-III, presence of pacemakers, sepsis or infective endocarditis and persistent bacteraemia. Adequate empirical treatment was not associated to survival. Conclusions: severity at onset, the development of septic complications and having a pacemaker are associated to mortality in patients with CNS bacteraemia; in our cohort, inadequate empirical treatment is not related to mortality(AU)

Phenotypic differences between coagulase-negative staphylococci isolated from seminal fluid of healthy men and men suffering from chronic prostatitis syndrome.

Chronic prostatitis syndrome (CPS) is a common urologic condition that many clinicians find difficult to diagnose and treat effectively. The most common causative agents of CPS among Gram-positive bacteria are coagulase-negative staphylococci (CNS). We compared phenotypic properties among CNS isolated from semen of healthy men and patients with CPS. A significantly higher proportion of CPS strains demonstrated inhibition of lysozyme and platelet microbicidal protein. Identifying these phenotypic characteristics in clinical laboratories would be helpful to differentiate which staphylococcal bacteriospermia case should be treated and which should not.