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Antibiotics are widely used as the most effective treatment for bacterial infections. However, the extensive use of antibiotics in clinical practice has led to elevated levels of bacterial antibiotic resistance in common clinical pathogens. One potential solution to this problem is the use of traditional Chinese herbal medicines to supplement antibiotic effectiveness. In this study, we utilized the matrine derived from the leguminous shrub Sophora flavescens and examined synergism with 17 clinically relevant antibiotics against Staphylococcus aureus, β-hemolytic Streptococcus, Pasteurella multocida, Escherichia coli and Salmonella paratyphi B using in vitro tests. Matrine exhibited significant antibacterial activity against these bacteria with minimum inhibitory concentrations (MIC) ranging from 4.69 to 9.38 mg/mL. Matrine combinations also yielded fractional inhibitory index values between 0.14 and 1 indicating additive or synergistic effects without antagonism. Furthermore, the mutation prevention concentration (MPC) analysis revealed that matrine could mitigate the impact of ceftiofur, doxycycline, gentamicin and tilmicosin for all 5 bacterial strains. The reduced MPC and MPC/MIC values of these antibiotics demonstrated a narrower selection window for drug-resistance mutations thereby retarding the development of drug resistance. The combination of matrine and antibiotics thereby enhanced the antibacterial activity of all test antibiotics while reducing the antibacterial impact of ceftiofur, doxycycline, gentamicin and tilmicosin on S. aureus and β-hemolytic Streptococcus. Additionally, matrine combinations with the latter drugs could lower the antimutation concentration thereby reducing the emergence of drug resistant strains. [ABSTRACT FROM AUTHOR]

The present study aimed to determine the in vitro antibacterial activity and the chemical composition of essential oils (EOs) from two medicinal plants (seeds of Carum copticum L. and leaves of Ziziphora clinopodioides Lam) against the bacterial plant pathogen Pseudomonas syringae pv. syringae. The sensitivity of P. syringae to the two types of EOs was investigated through three methods including disc diffusion, well diffusion, and vapor phase tests. Gas chromatography (GC) and gas chromatography attached to a mass spectrometer (GC-MS) were used to identify and quantify the essential oil compounds. The greatest growth inhibition zones for disc diffusion, well diffusion, and vapor tests were observed for the highest essential oil volume (50 µL) of Z. clinopodioides as 0.925 cm, 1.75 cm, and 1.45 cm, respectively. Concerning the EOs from C. copticum seeds, the diameters of growth inhibition zones were 0.775 cm, 1 cm, and 0 cm, respectively. Based on the obtained results, the highest antibacterial activity, with a growth inhibition zone of 1.75 cm, belonged to 50 µL EOs of Z. clinopodioides on Luria-Bertani (LB) agar medium. The minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC) for the EOs of Z. clinopodioides were 8 µL mL−1 and 1 µL mL−1 in LB agar medium. The MBC and MIC values for EOs of C. copticum were 16 µL mL−1 and 1 µL mL−1, in LB agar medium, respectively. According to the chromatography results, 16 different compounds were identified in the EOs of C. copticum, of which thymol (54.6%) was the major constituent. Moreover, 27 different compounds were identified in the Z. clinopodioides EOs, of which pulegone (23%) and 1,8 cineole (20.3%) were the main essential oil constituents. The results demonstrated that the EOs of Z. clinopodioides plants had higher chemical diversity and displayed stronger antibacterial activities against P. syringe pv. syringae, compared to those of C. copticum. [ABSTRACT FROM AUTHOR]

Identifying and monitoring the efficiency of alternative biocides that are presently used in livestock is gaining vast attention. The objective of this study was to determine, in vitro, the antibacterial activity of nine commercial water disinfectants, acidifiers, and glyceride blends against clinical isolates or reference strains of zoonotic pathogens belonging to the genera Escherichia spp., Salmonella spp., Campylobacter spp., Listeria spp., and Staphylococcus spp. For each product, the antibacterial activity was tested in concentrations ranging from 0.002 to 1.136% v/v and expressed as the minimum concentration of the product that inhibits bacterial growth (MIC). Water disinfectants Cid 2000™ and Aqua-clean® recorded MICs ranging from 0.002 to 0.142% v/v, while the lowest MICs were recorded at two strains of Campylobacter (0.002–0.004% v/v). Virkon® S displayed various MICs (0.013–0.409% w/v) and was highly effective at suppressing the growth of Gram-positive bacteria such as S. aureus (0.013–0.026% w/v). The MICs of water acidifiers (Agrocid Super™Oligo, Premium acid, and Ultimate acid) and glyceride blends (CFC Floramix, FRA®LAC34, and FRA®Gut Balance) ranged from 0.036 to 1.136% v/v, and for most of these products, MICs were closely correlated by their ability to modify the pH of the culture medium close to 5. In conclusion, most of the tested products showed promising antibacterial activity; as a result, they would be good candidates for pathogen control in poultry farms and for reducing the emergence of antimicrobial resistance. However, further in vivo studies are recommended to provide relevant information for the underlying mechanisms, as well as for the establishment of the optimal dosage scheme for each product and their possible synergies. [ABSTRACT FROM AUTHOR]

Lentinus squarrosulus (Mont.) is a wide edible mushroom widely consumed in Thailand. Ethanol extract was extracted from mycelium of L. squarrosulus No. 2 and Lentinus basidiocarp obtained from the local market at Mahasarakham province using 50% ethanol solvent. The effect of ethanolic extracts was tested for inhibition to some pathogenic bacteria. Antibacterial activity was tested by Poison food technique, it was found that 50 % ethanol extract from mycelium at concentrations of 10%, 15%, and 30% was effective to inhibit Bacillus cereus at the highest level (+++) and mycelium extract at the concentrations of 15% and 30% can inhibit Staphylococcus aureus with low level (+). But all concentrations of L. squarrosulus basidiocarp extract unable to inhibit the growth of B. cereus, Escherichia coli, Pseudomonas aeruginosa and S. aureus. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of ethanolic extract from mycelium inhibit B. cereus was 125 mg/ml. The results indicate that the potential of L. squarrosulus mycelium is an excellent source of antimicrobial agents.

Rapidly growing mycobacteria (RGM) cause an increasing international concern, mainly due to their natural resistance to many antibiotics. The aim of this study was to conduct species identification and determine the antimicrobial susceptibility profiles of RGM isolated in Poland. Antimicrobial susceptibility was tested using broth microdilution and the RAPMYCOI panel. A total of 60 strains were analysed, including the following species: M. fortuitum complex (30), M. abscessus subsp. abscessus (16), M. abscessus subsp. massiliense (7), M. chelonae (5), and M. mucogenicum (2). For 12 M. abscessus subsp. abscessus strains, the presence of the erm 41T28 genotype associated with inducible macrolide resistance and a functional erm gene was confirmed. A MUT2 mutation in the rrl gene (constitutive resistance) was identified for two strains from the subtype M. abscessus subsp. massiliense. Among the 15 tested antibiotics, amikacin and linezolid had the strongest antimycobacterial activity. Most of the tested strains were resistant to doxycycline and trimethoprim/sulfamethoxazole. Tigecycline MICs were low for all tested strains. Findings from our study highlight the importance of correct identification of clinical isolates and antimicrobial susceptibility testing. [ABSTRACT FROM AUTHOR]

Hussain Sagar Lake (17.4239° N, 78.4738° E) located at the heart of the capital of Telangana state, Hyderabad, is well known by many as a tourist spot. However, during the recent years, this lake has been contaminated by various industries surrounding the lake, especially from the Kukatpally channel and NTR Marg. Such inflow and heavy dumping of wastes have led to huge amount of toxic silt at the bottom and have taken a toll on the holding capacity of the lake. This paper focuses on the effect of bacteria on the heavy metals in the lake soil samples. Cadmium sulfate was used to prepare the heavy metal sample and a cadmium-resistant bacterium was obtained after 48 h of treatment. Among the eight bacterial isolates, one showed cadmium absorption capacity with a minimal inhibitory concentration of 500 mg/l of synthetically prepared solution. The sample also showed resistance to other heavy metals like copper and zinc. The bacterium from this sample was identified to be Pseudomonas fluorescens which was used for optimization whose growth was assessed based on UV absorbance at 600 nm. The optimum solution was obtained at a pH of 6.01 and a temperature of 32.7 °C, and the removal rate for 50 mg/l of cadmium was observed to be 90% and that of 100 mg/l was found to be 72%. [ABSTRACT FROM AUTHOR]

ABSTRACT Defining the precise relationship between resistance mutations and quantitative phenotypic drug susceptibility testing will increase the value of whole-genome sequencing (WGS) for predicting tuberculosis drug resistance. However, a large number of WGS data sets currently lack corresponding quantitative phenotypic data—the MICs. Using MYCOTBI plates, we determined the MICs to nine antituberculosis drugs for 154 clinical multidrug-resistant tuberculosis isolates from the Shenzhen Center for Chronic Disease Control in Shenzhen, China. Comparing MICs with predicted drug-resistance profiles inferred by WGS showed that WGS could predict the levels of resistance to isoniazid, rifampicin, streptomycin, fluoroquinolones, and aminoglycosides. We also found some mutations that may not be associated with drug resistance, such as EmbB D328G, mutations in the gid gene, and C−12T in the eis promoter. However, some strains carrying the same mutations showed different levels of resistance to the corresponding drugs. The MICs of different strains with the RpsL K88R, fabG1 C−15T mutations and some with mutations in embB and rpoB, had MICs to the corresponding drugs that varied by 8-fold or more. This variation is unexplained but could be influenced by the bacterial genetic background. Additionally, we found that 32.3% of rifampicin-resistant isolates were rifabutin-susceptible, particularly those with rpoB mutations H445D, H445L, H445S, D435V, D435F, L452P, S441Q, and S441V. Studying the influence of bacterial genetic background on the MIC and the relationship between rifampicin-resistant mutations and rifabutin resistance levels should improve the ability of WGS to guide the selection of medical treatment regimens. IMPORTANCE Whole-genome sequencing (WGS) has excellent potential in drug-resistance prediction. The MICs are essential indications of adding a particular antituberculosis drug dosage or changing the entire treatment regimen. However, the relationship between many known drug-resistant mutations and MICs is unclear, especially for rarer ones. The results showed that WGS could predict resistance levels to isoniazid, rifampicin, streptomycin, fluoroquinolones, and aminoglycosides. However, some mutations may not be associated with drug resistance, and some others may confer various MICs to strains carrying them. Also, 32.3% of rifampicin (RIF)-resistant strains were classified as sensitive to rifabutin (RFB), and some mutations in the rpoB gene may be associated with this phenotype. Our data on the MIC distribution of strains with some rarer mutations add to the accumulated data on the resistance level associated with such mutations to help guide further research and draw meaningful conclusions.

The preparation of metal nanoparticles (NPs) on metal-organic frameworks (MOFs) has aroused great interest in the field of bacteriostasis. However, MOFs as nano-supports to form uniformly dispersed NPs loadings has still been in the exploratory stage. The use of Ag x /Cu-BTC as nano-supports was investigated for the preparation of silver nanoparticles and their antibacterial activity. The post-synthetic exchange method was used to achieve the in situ loading of Ag NPs on copper(II) benzene-1,3,5-tricarboxylate (Cu-BTC) nano-supports and the Ag x /Cu-BTC (x = 7, 14, 21 % molar ratio) were successful synthesized. The crystal structure characteristics and the physicochemical properties of the prepared materials were analyzed by SEM, EDS, FT-IR, XRD, XPS, TG, and BET. Using Bacillus subtilis as the experimental strain and Cu-BTC as the antibacterial activity standard, the antibacterial performance of Ag x /Cu-BTC was evaluated using the minimum inhibitory concentration test and the Kirby-Bauer test. According to the reaction mechanism of related antibacterial materials, a reasonable mechanism explanation was given for the antibacterial effect of Ag NPs. All characterization results demonstrated that the preparation of Ag NPs using Cu-BTC as nano-supports did not destroy the structure of Cu-BTC. Ag x /Cu-BTC still maintained the ortho-octahedral structure, which demonstrated the in situ preparation of Ag NPs was achieved. With the ratio of Ag NPs increased, the specific surface area became smaller, the average pore size became larger, and the thermal stability was enhanced. Ag x /Cu-BTC showed significantly stronger antibacterial activity than Cu-BTC. Among the synthesized materials, Ag 21 /Cu-BTC showed the strongest antibacterial activity, which was due to the more adsorption of Ag NPs onto the cell wall, causing irregular pits and damaging the cell wall and cell membrane. As a result, the cell membrane permeability was altered, allowing more nutrients to flow out of the cell. Ag NPs entered the cell causing a significant increase in the level of reactive oxygen species (ROS), leading to cell damage or death. The higher the concentration of Ag NPs, the more Ag+ was released and the stronger the antibacterial activity. Overall, the in situ preparation of Ag NPs by MOFs nano-supports has the potential to enhance the antibacterial performance of Ag NPs, making them more effective in applications. [Display omitted] • Using Cu-BTC as nano-supports, Ag x /Cu-BTC with Ag NPs were successfully synthesized and applied in antibacterial. • Ag NPs caused the rough and disordered filaments attached to the surface and enhanced the antibacterial effect. • Cu-BTC in Ag x /Cu-BTC provided antibacterial ability besides Ag NPs, enhancing the antibacterial performance. [ABSTRACT FROM AUTHOR]

Lentinus squarrosulus (Mont.) is a wide edible mushroom widely consumed in Thailand. Ethanol extract was extracted from mycelium of L. squarrosulus No. 2 and Lentinus basidiocarp obtained from the local market at Mahasarakham province using 50% ethanol solvent. The effect of ethanolic extracts was tested for inhibition to some pathogenic bacteria. Antibacterial activity was tested by Poison food technique, it was found that 50 % ethanol extract from mycelium at concentrations of 10%, 15%, and 30% was effective to inhibit Bacillus cereus at the highest level (+++) and mycelium extract at the concentrations of 15% and 30% can inhibit Staphylococcus aureus with low level (+). But all concentrations of L. squarrosulus basidiocarp extract unable to inhibit the growth of B. cereus, Escherichia coli, Pseudomonas aeruginosa and S. aureus. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of ethanolic extract from mycelium inhibit B. cereus was 125 mg/ml. The results indicate that the potential of L. squarrosulus mycelium is an excellent source of antimicrobial agents. [ABSTRACT FROM AUTHOR]

Therapeutic drug monitoring is considered to be an effective tool for the individualized use of voriconazole. However, drug concentration measurement alone doesn't take into account the susceptibility of the infecting microorganisms to the drug. Linking pharmacodynamic data with the pharmacokinetic profile of individuals is expected to be an effective method to predict the probability of a certain therapeutic outcome. The objective of this study was to individualize voriconazole regimens by integrating individual pharmacokinetic parameters and pathogen susceptibility data through Monte Carlo simulations The individual pharmacokinetic parameters of 35 hospitalized patients who received voriconazole were calculated based on a validated population pharmacokinetic model. The area under the concentration-time curve for free drug/minimal inhibitory concentration (fAUCss/MIC) > 25 was selected as the pharmacokinetic/pharmacodynamic (PK/PD) parameter predicting the efficacy of voriconazole. The cumulative fraction of response (CFR) of the target value was assessed. To verify this conclusion, a logistic regression analysis was used to explore the relationship between actual clinical efficiency and the CFR value. For the 35 patients, the area under the free drug concentration-time curve (fAUCss) was calculated to be 34.90 ± 21.67 mgh/L. According to the dualistic logistic regression analysis, the minimal inhibitory concentration (MIC) value of different kinds of fungi had a great influence on the effectiveness of clinical treatment. It also showed that the actual clinical efficacy and the CFR value of fAUCss/MIC had a high degree of consistency. The results suggest that it is feasible to individualize voriconazole dosing and predict clinical outcomes through the integration of data on pharmacokinetics and antifungal susceptibility. [ABSTRACT FROM AUTHOR]

Therapeutic drug monitoring is considered to be an effective tool for the individualized use of voriconazole. However, drug concentration measurement alone doesn’t take into account the susceptibility of the infecting microorganisms to the drug. Linking pharmacodynamic data with the pharmacokinetic profile of individuals is expected to be an effective method to predict the probability of a certain therapeutic outcome. The objective of this study was to individualize voriconazole regimens by integrating individual pharmacokinetic parameters and pathogen susceptibility data through Monte Carlo simulations The individual pharmacokinetic parameters of 35 hospitalized patients who received voriconazole were calculated based on a validated population pharmacokinetic model. The area under the concentration-time curve for free drug/minimal inhibitory concentration (fAUCss/MIC) > 25 was selected as the pharmacokinetic/pharmacodynamic (PK/PD) parameter predicting the efficacy of voriconazole. The cumulative fraction of response (CFR) of the target value was assessed. To verify this conclusion, a logistic regression analysis was used to explore the relationship between actual clinical efficiency and the CFR value. For the 35 patients, the area under the free drug concentration-time curve (fAUCss) was calculated to be 34.90 ± 21.67 mgh/L. According to the dualistic logistic regression analysis, the minimal inhibitory concentration (MIC) value of different kinds of fungi had a great influence on the effectiveness of clinical treatment. It also showed that the actual clinical efficacy and the CFR value of fAUCss/MIC had a high degree of consistency. The results suggest that it is feasible to individualize voriconazole dosing and predict clinical outcomes through the integration of data on pharmacokinetics and antifungal susceptibility.

Rapidly growing mycobacteria (RGM) cause an increasing international concern, mainly due to their natural resistance to many antibiotics. The aim of this study was to conduct species identification and determine the antimicrobial susceptibility profiles of RGM isolated in Poland. Antimicrobial susceptibility was tested using broth microdilution and the RAPMYCOI panel. A total of 60 strains were analysed, including the following species: M. fortuitum complex (30), M. abscessus subsp. abscessus (16), M. abscessus subsp. massiliense (7), M. chelonae (5), and M. mucogenicum (2). For 12 M. abscessus subsp. abscessus strains, the presence of the erm 41T28 genotype associated with inducible macrolide resistance and a functional erm gene was confirmed. A MUT2 mutation in the rrl gene (constitutive resistance) was identified for two strains from the subtype M. abscessus subsp. massiliense. Among the 15 tested antibiotics, amikacin and linezolid had the strongest antimycobacterial activity. Most of the tested strains were resistant to doxycycline and trimethoprim/sulfamethoxazole. Tigecycline MICs were low for all tested strains. Findings from our study highlight the importance of correct identification of clinical isolates and antimicrobial susceptibility testing.

Fungi from the genus Candida are very important human and animal pathogens. Many strains can produce biofilms, which inhibit the activity of antifungal drugs and increase the tolerance or resistance to them as well. Clinically, this process leads to persistent infections and increased mortality. Today, many Candida species are resistant to drugs, including C. auris, which is a multiresistant pathogen. Natural compounds may potentially be used to combat multiresistant and biofilm-forming strains. The aim of this review was to present plant-derived preparations and compounds that inhibit Candida biofilm formation by at least 50%. A total of 29 essential oils and 16 plant extracts demonstrate activity against Candida biofilms, with the following families predominating: Lamiaceae, Myrtaceae, Asteraceae, Fabaceae, and Apiacae. Lavandula dentata (0.045–0.07 mg/L), Satureja macrosiphon (0.06–8 mg/L), and Ziziphora tenuior (2.5 mg/L) have the best antifungal activity. High efficacy has also been observed with Artemisia judaica, Lawsonia inermis, and Thymus vulgaris. Moreover, 69 plant compounds demonstrate activity against Candida biofilms. Activity in concentrations below 16 mg/L was observed with phenolic compounds (thymol, pterostilbene, and eugenol), sesquiterpene derivatives (warburganal, polygodial, and ivalin), chalconoid (lichochalcone A), steroidal saponin (dioscin), flavonoid (baicalein), alkaloids (waltheriones), macrocyclic bisbibenzyl (riccardin D), and cannabinoid (cannabidiol). The above compounds act on biofilm formation and/or mature biofilms. In summary, plant preparations and compounds exhibit anti-biofilm activity against Candida. Given this, they may be a promising alternative to antifungal drugs. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides (AMPs) represent a promising and effective alternative for combating pathogens, having some advantages compared to conventional antibiotics. However, AMPs must also contend with complex and specialised Gram-negative bacteria envelops. The variety of lipopolysaccharide and phospholipid composition in Gram-negative bacteria strains and species are decisive characteristics regarding their susceptibility or resistance to AMPs. Such biological and structural barriers have created delays in tuning AMPs to deal with Gram-negative bacteria. This becomes even more acute because little is known about the interaction AMP–Gram-negative bacteria and/or AMPs’ physicochemical characteristics, which could lead to obtaining selective molecules against Gram-negative bacteria. As a consequence, available AMPs usually have highly associated haemolytic and/or cytotoxic activity. Only one AMP has so far been FDA approved and another two are currently in clinical trials against Gram-negative bacteria. Such a pessimistic panorama suggests that efforts should be concentrated on the search for new molecules, designs and strategies for combating infection caused by this type of microorganism. This review has therefore been aimed at describing the currently available AMPs for combating Gram-negative bacteria, exploring the characteristics of these bacteria’s cell envelop hampering the development of new AMPs, and offers a perspective regarding the challenges for designing new AMPs against Gram-negative bacteria.

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Background. Vancomycin, the first line antibiotic for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia, is often administered inappropriately when MIC is greater than 2 µg/mL, including ‘susceptible’ strains. This study assessed the discordance of vancomycin minimum inhibitory concentration (MIC) for methicillin-resistant Staphylococcus aureus (MRSA). Methods. In total, 229 MRSA isolates from blood cultures collected between 2009 and 2015 at a tertiary hospital in Taiwan were examined. The MICs of vancomycin were measured using Vitek 2, E-test, and standard broth microdilution at the level of 2 µg/mL. Results. The geometric mean of the MICs of hospital-acquired MRSA was higher than that of community-acquired MRSA (P < 0.001), with the exact agreement rates (with broth microdilution) at 2 µg/mL being 53.6% in Vitek 2 and 86.7% in E-test. Overall, E-test (98.1%) had more categorical accordance than did Vitek 2 (94.0%; P = 0.026). Vitek 2 had a tendency to overestimate MRSA in high-MIC isolates, whereas E-test inclined underestimation in low-MIC isolates. Surprisingly, the discordance rates of MRSA vancomycin MICs were higher in hospital-acquired isolates (13.3%–17.0%) than in community-acquired isolates (6.2%–7.0%). Conclusion. The Infectious Diseases Society of America recommends the use of alternative antimicrobial agents when vancomycin MIC is ≥ 2 µg/mL; in this study, only 53.6% of the isolates tested using Vitek 2 showed a high MIC in the broth microdilution method. Accurate identification of the resistance profile is a key component of antimicrobial stewardship programs. Therefore, to reduce inappropriate antibiotic use and mitigate the emergence of resistant strains, we recommend using complementary tests such as E-test or Broth microdilution to verify the MIC before administering second-line antibiotics. Strengths. (1) We compared the categorical agreement between different methods measuring MRSA MICs level. (2) Physicians should incorporate this information and consider a complementary test to verify the appropriateness of the decision of shifting vancomycin to second-line antibiotic treatment to improve patients’ prognosis. (3) MRSA-vancomycin MICs at a cutoff of 2 µg/mL obtained using Vitek II exhibited a higher sensitivity level and negative predictive value than those obtained using E-test in the prediction of categorical agreement with standard broth microdilution. Limitation. (1) Our research was based on a single hospital-based study. (2) The MRSA strains in this study were stored for more than 12 months after isolation. (3) We did not collect information on clinical prognosis. [ABSTRACT FROM AUTHOR]

The growing numbers of pathogenic bacteria acquiring multidrug resistance are posing the challenges to develop novel therapeutic approaches. Photodynamic bacterial inactivation assaults multiple subcellular targets of pathogenic bacteria, including Staphylococcus aureus, with low tendency to induce further resistance. A wide range of aPDI photosensitizers were investigated for localized infections, including endogenous porphyrins and encapsulated sensitizers in nanoparticles. This mini review presents the concepts of aPDI, a field consisting of more than 3000 research articles published over 30 years. Mutated PBP membrane enzymes of multiantibiotic resistant S. aureus are plausible targets of aPDI. Synergistic aPDI using simultaneously DP, light irradiation and the antibiotic oxacillin, was recently described, eliminating temporarily oxacillin resistance. Additive antimicrobial effects were achieved with DP‐aPDI combined with additional classes of antibiotics. We propose that mutual aPDI adjuvant with antibiotics or other toxic molecules is opening a new therapeutic window for topical life‐threatening infections, without induction of further resistance. [ABSTRACT FROM AUTHOR]

We determined minimal inhibitory concentration (MIC) of single active substances (a.s) of fungicides, twelve mixtures of two a.s and four a.s mixture. Additionally fractional inhibitory concentration index (FICI) of combined a.s. was calculated. Fungal and oomycete pathogens included Fusarium culmorum, Colletotrichum coccodes, Penicillium verrucosum, Sclerotinia sclerotiorum, Botrytis cinerea, Altemaria alternata, Aspergillus candidus, Monilinia fructicola, Septoria tritici and oomycete Phytophthora infestans. MIC were ranged from 0.1 μg/ml for fluazinam to 4954.5 μg/ml for cymoxaniL MIC of combined a.s were ranged from 0.00004 μg/ml for picoxystrobin+fenamidone to 4955 μg/ml for cymoxanil+ carboxin. Dodine+picoxystrobin had shown the most effective inhibitory and synergistic action against seven fungal or oomycete species (0.001 μg/ml- 35.9 μg/ml). The highest decrease of MIC values of dodine+picoxystrobin compared to their separate application indicate that these compounds should be considered to create novel commercial formulations offungicides. [ABSTRACT FROM AUTHOR]

The present research study investigated the susceptibility of common mastitis pathogens--obtained from clinical mastitis cases on 58 Northern German dairy farms--to routinely used antimicrobials. The broth microdilution method was used for detecting the Minimal Inhibitory Concentration(MIC)ofStreptococcus agalactiae (n=51),Streptococcus dysgalactiae (n=54),Streptococcusuberis (n = 50), Staphylococcus aureus (n = 85), non-aureus staphylococci (n = 88), Escherichia coli (n = 54) and Klebsiella species (n = 52). Streptococci and staphylococci were tested against cefquinome, cefoperazone, cephapirin, penicillin, oxacillin, cloxacillin, amoxicillin/clavulanic acid and cefalexin/kanamycin. Besides cefquinome and amoxicillin/clavulanic acid, Gram-negative pathogens were examined for their susceptibility to marbofloxacin and sulfamethoxazole/trimethoprim. The examined S. dysgalactiae isolates exhibited the comparatively lowest MICs. S. uberis and S. agalactiae were inhibited at higher amoxicillin/clavulanic acid and cephapirin concentration levels, whereas S. uberis isolates additionally exhibited elevated cefquinome MICs. Most Gram-positive mastitis pathogens were inhibited at higher cloxacillin than oxacillin concentrations. The MICs of Gram-negative pathogens were higher than previously reported, whereby 7.4%, 5.6% and 11.1% of E. coli isolates had MICs above the highest concentrations tested for cefquinome, marbofloxacin and sulfamethoxazole/trimethoprim, respectively. Individual isolates showed MICs at comparatively higher concentrations, leading to the hypothesis that a certain amount of mastitis pathogens on German dairy farms might be resistant to frequently used antimicrobials. [ABSTRACT FROM AUTHOR]

The incidence of fungal infections has been steadily increasing in recent years. Systemic mycoses are characterized by the highest mortality. At the same time, the frequency of infections caused by drug-resistant strains and new pathogens e.g., Candida auris increases. An alternative to medicines may be essential oils, which can have a broad antimicrobial spectrum. Rich in the essential oils are plants from the Lamiaceae family. In this review are presented antifungal activities of essential oils from 72 Lamiaceae plants. More than half of these have good activity (minimum inhibitory concentrations (MICs) < 1000 μg/mL) against fungi. The best activity (MICs < 100) have essential oils from some species of the genera Clinopodium, Lavandula, Mentha, Thymbra, and Thymus. In some cases were observed significant discrepancies between different studies. In the review are also shown the most important compounds of described essential oils. To the chemical components most commonly found as the main ingredients include β-caryophyllene (41 plants), linalool (27 plants), limonene (26), β-pinene (25), 1,8-cineole (22), carvacrol (21), α-pinene (21), p-cymene (20), γ-terpinene (20), and thymol (20). [ABSTRACT FROM AUTHOR]

Antibiotic resistance in bacteria is a serious threat to public health due to limited therapeutic options. Bactericidal agents with polypharmacological profiles or targeting bacterial membrane have lower propensity to develop resistance. Mitocurcumin (MitoC) is a novel compound synthesized by triphenyl-phosphonium conjugation with curcumin. Here, we demonstrate the antibacterial properties of MitoC that structurally differs markedly from the known antibacterial compounds. MitoC shows efficient bactericidal activity against Gram-positive and Gram-negative bacteria, including Mycobacteria, with MIC values in 1.5–12.5 μM range, but does not affect the viability of human leukocytes and human lung normal cell lines. Even at sub-MIC values, MitoC displays bactericidal properties. MitoC bactericidal action involves rapid disruption of bacterial membrane potential. Scanning electron microscope images of MitoC treated cells show structural deformations in terms of shrinking, loss of turgidity and formation of blisters and bubbles on their surface. Although MitoC increases ROS levels in bacterial cells, it may not be the primary cause of cell death as prior treatment with anti-oxidant trolox did not affect the MIC. This is the first report on bactericidal activity of MitoC and represents an excellent alternative for development of new generation bactericidal molecules that may be slow to develop resistance. • Mitocurcumin belongs to structurally new class of bactericidal compound. • It displays bactericidal action even at sub-MIC levels in a ROS independent manner. • It depolarizes membrane potential suggesting membrane damaging activity. • Membrane damage is validated by fluorescence and SEM studies. [ABSTRACT FROM AUTHOR]

The main goal of this work was to approach food industry conditions in the comparison of the susceptibility of biofilms of Listeria monocytogenes to the biocides benzalkonium chloride (BAC) and peracetic acid (PAA). Twelve isolates of L. monocytogenes , including nine well characterized BAC resistant strains were used. Biofilms were produced on stainless steel coupons (SSC), at 11 °C (refrigeration temperature) or at 25 °C (room temperature), in culture media simulating clean (nutrient limiting) or soiled (nutrient rich) growth conditions. Neither different nutrient availability nor growth temperature showed significant effect (p >.05) on biofilm formation. PAA confirmed to be more effective than BAC in biofilm elimination. Biofilms formed under nutritional stress tended to differentiate more the response to BAC of the resistant or sensitive strains, but the resistant or sensitive phenotype of the planktonic cells did not dictate biofilm susceptibility. Unlabelled Image • Resistant or sensitive strain phenotype did not dictate biofilm susceptibility. • Biofilm formation was not affected by nutrient availability nor growth temperature. • Biofilms grown under nutrient scarcity differentiate more their response to BAC. [ABSTRACT FROM AUTHOR]

Numerous studies have been reported on today's ubiquitous presence of antibiotics in surface waters causing the emergence of multidrug-resistant bacteria. Advanced water treatment procedures aim at the complete prevention and elimination of antibiotics from entering natural water bodies. In this study, photoinduced degradation processes using UVC-irradiation were applied toward selected fluoroquinolone, tetracycline, macrolide, and sulfonamide antibiotics. Photodegradation products were elucidated using high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS). Rate constants and quantum efficiencies were determined for the active substances and their photo-transformation products. As a measure of ecotoxicity, minimum inhibitory and half-maximal inhibitory concentrations were determined against the Gram-negative bacterium Pseudomonas fluorescens and the Gram-positive Bacillus subtilis in a standard assay format. These values were further recorded as a function of UV exposure time. The irradiation time-dependent increase of minimum inhibitory concentration (MIC) values agreed well with the kinetic models. After 10 min of irradiation, the compound solutions ceased to inhibit bacterial cell growth, indicating removal of the pharmaceutical activity. These findings were found in agreement with quantitative structure–activity relationship analysis. The combination of microbiological activity testing, molecular structure analysis, chemical kinetic investigation, and quantitative structure–activity relationship models proved to be able to predict irradiation times and evaluate potential ecotoxicological hazard of the irradiated drugs. [ABSTRACT FROM AUTHOR]

Respiratory infection is highly prevalent in HIV-infected patients and S. pneumoniae was a leading cause. The aim of this study was to isolate and identify Streptococcus pneumoniae associated with pulmonary infection among HIV Clients Attending Aminu Kano Teaching Hospital (AKTH). A total of 300 samples comprising sample from 180 HIV seropositive patients and 120 HIV seronegative patients as a (control) were enrolled in this study.) For the 180 HIV seropositive patients, 105(58.3%) were females, and 75(41.7%) were males. Among the HIV negative subjects 64(53.3%) were males and 56(46.7%) were females. The incident of Streptococcus pneumoniae isolates associated with pneumonia in HIV/AIDS seropositive patients in relation to age group in this study showed the higher prevalence of 15(51.72%), among the age groups of 30-39, had the highest of prevalence of 15(51.72%), which occur more common in HIV infected patients while for HIV seronegative patients age group 10-19 had the highest incidence of 7(29.17%).Result showed no significant difference in the prevalence of S .pneumoniae among the HIV seropositive and seronegative patients (P > 0.05) .Antimicrobial susceptibility showed that Ciprofloxacin 25(86.2%), was found to be most active invitro against the isolates followed by Oxacillin 21(72.4%), Augmentin19 (65.5), Chloramphenicol 15(51.7%). Tetracycline, 14(48.3%), Clindamycin 14(48.3) and Erythromycin 10(34.5%). Result showed no significant difference in the levels of antibiotic susceptibilities and resistance observed (p > 0.05). The CD4 cells counts for the HIV seropositve patients were 161(89.4%) 350 cells/ml and 19(10.6%) <350 cells/m recorded as normal and low respectively. There was significant difference (p <0.05) for the CD4 cells counts of the study population with the prevalence of Streptococcus pneumoniae isolates among the HIV seropositive patients (P 0.000 <0.05). PCR amplification for Streptococcus pneumoniae penicillin resistance genes showed that Only 2(33.3%) out of 6 resistant isolates possed the pneumococcal pbp2b resistance gene. According to the findings, the pbp2b gene can play a role of fundamentalimportance in the resistance of S. pneumoniae. Modify heterogeneity in antibiotic use, which several antibiotics are taken in a rotation against taking just 1 antibiotic such that isolates resistant to 1 antibiotic are killed when the subsequent antibiotic is taken. [ABSTRACT FROM AUTHOR]

The present research study investigated the susceptibility of common mastitis pathogens—obtained from clinical mastitis cases on 58 Northern German dairy farms—to routinely used antimicrobials. The broth microdilution method was used for detecting the Minimal Inhibitory Concentration (MIC) of Streptococcus agalactiae (n = 51), Streptococcus dysgalactiae (n = 54), Streptococcus uberis (n = 50), Staphylococcus aureus (n = 85), non-aureus staphylococci (n = 88), Escherichia coli (n = 54) and Klebsiella species (n = 52). Streptococci and staphylococci were tested against cefquinome, cefoperazone, cephapirin, penicillin, oxacillin, cloxacillin, amoxicillin/clavulanic acid and cefalexin/kanamycin. Besides cefquinome and amoxicillin/clavulanic acid, Gram-negative pathogens were examined for their susceptibility to marbofloxacin and sulfamethoxazole/trimethoprim. The examined S. dysgalactiae isolates exhibited the comparatively lowest MICs. S. uberis and S. agalactiae were inhibited at higher amoxicillin/clavulanic acid and cephapirin concentration levels, whereas S. uberis isolates additionally exhibited elevated cefquinome MICs. Most Gram-positive mastitis pathogens were inhibited at higher cloxacillin than oxacillin concentrations. The MICs of Gram-negative pathogens were higher than previously reported, whereby 7.4%, 5.6% and 11.1% of E. coli isolates had MICs above the highest concentrations tested for cefquinome, marbofloxacin and sulfamethoxazole/trimethoprim, respectively. Individual isolates showed MICs at comparatively higher concentrations, leading to the hypothesis that a certain amount of mastitis pathogens on German dairy farms might be resistant to frequently used antimicrobials.

The incidence of fungal infections has been steadily increasing in recent years. Systemic mycoses are characterized by the highest mortality. At the same time, the frequency of infections caused by drug-resistant strains and new pathogens e.g., Candida auris increases. An alternative to medicines may be essential oils, which can have a broad antimicrobial spectrum. Rich in the essential oils are plants from the Lamiaceae family. In this review are presented antifungal activities of essential oils from 72 Lamiaceae plants. More than half of these have good activity (minimum inhibitory concentrations (MICs) < 1000 µg/mL) against fungi. The best activity (MICs < 100) have essential oils from some species of the genera Clinopodium, Lavandula, Mentha, Thymbra, and Thymus. In some cases were observed significant discrepancies between different studies. In the review are also shown the most important compounds of described essential oils. To the chemical components most commonly found as the main ingredients include β-caryophyllene (41 plants), linalool (27 plants), limonene (26), β-pinene (25), 1,8-cineole (22), carvacrol (21), α-pinene (21), p-cymene (20), γ-terpinene (20), and thymol (20).

Background: One of the main causes of sexually transmitted diseases is group B β- hemolytic streptococci (GBS) multiplying in the genital tracts. Penicillin is the most common drug for the treatment of infections caused by these bacteria, but in patients suffering from Penicillin allergy, Erythromycin and Clindamycin are used as alternative therapeutic drugs against GBS. Recently, resistance to these drugs has been reported more often. In this study, efforts have been made to determine the prevalence and antibiotic resistance of GBS. Methods: Modified Christie Atkins Munch-Petersen (CAMP) test was conducted on over 2400 samples of urine and discharge taken from vagina, urethra and prostate. The drug sensitivity was performed by double disk sensitivity tests to Bacitracin, Trimethoprim, and Sulfamethoxazole and then the resistant samples were investigated by E-test to determine the minimal inhibitory concentrations (MICs) value. Results: Twenty-three vaginal and 10 urethral discharge, 27urine and 6 prostatic secretion samples were GBS positive. The most symbiotic microorganisms with GBS were strains of Enterococci (90%), Staphylococcus saprophyticus (25%) and Candida albicans (6%). The disk diffusion method showed 18 cases with Penicillin resistance (MIC: 1.5 mg/ml). Conclusion: Taken together, GBS carriers’ rate in this study was found 20.65% (8.24% men and 12.4% women). Furthermore, findings showed high-level resistance to Erythromycin and Clindamycin.

Infections caused by non-albicans Candida spp. are an important medical problem in people from risk groups, e.g. hematooncological patients. The aim of this paper was to analyse the in vitro activity of micafungin against 30 clinical isolates of non-albicans Candida spp. (C. glabrata, C. famata, C. tropicalis, C. inconspicua, C. lusitaniae, C. parapsilosis, C. krusei) by way of the E-test procedure, allowing determination of minimal inhibitory concentration (MIC). Data presented in this paper indicate that most of the studied clinical isolates - 27 (90%) showed sensitivity to micafungin, with MIC values ranging from 0.004 to 2 mg/l, while 3 (10%) isolates, including 2 isolates of C. tropicalis and 1 isolate of C. famata, were resistant to micafungin, with MIC values > 32 mg/l. The MIC50 and MIC90 values of micafungin, defined as MIC inhibited growth of 50% or 90% of the isolates studied, were 0.008 mg/l or 2 mg/l, respectively. In the case of C. glabrata isolates, MICs ranged from 0.004 to 0.016 mg/l, while MIC50 was 0.004 mg/l and MIC90 - 0.008 mg/l. Our data confirm the utility of micafungin for the therapy of the infections caused by non-albicans Candida spp., especially C. glabrata.

For the treatment and prevention of ocular diseases, most patients are treated with conventional drug delivery formulations such as eye drops or ointments. However, eye drops and ointments suffer from low patient compliance and low effective drug concentration at the target site. Therefore, new medical devices are being explored to improve drug delivery to the eye. Over the years, various delivery devices have been developed including resorbable devices, oval- and ring-shaped devices, rod-shaped devices, punctum plugs, contact lenses and corneal shields. Only a few devices (eg. Mydriasert ® , Ozurdex ® , Surodex ® , Iluvien ® , Lacrisert ® and Retisert ® ) have made it to the market while others are being investigated in clinical trials. Altogether, there is a need for enhanced topical drug delivery. Only by working together (academia, industry and authorities) and by exploring parallel strategies (new drug delivery devices, enhanced drug formulations, better understanding of the pharmacokinetic properties), the therapeutic effect of drug treatments can be improved. [ABSTRACT FROM AUTHOR]

Staphylococcus (S.) aureus is considered as a major mastitis pathogen, with considerable epidemiological information on such infections while the epidemiology of coagulase-negative staphylococci (CNS) is more controversial. The aim of this study was to use matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) technology for identification of staphylococci isolated from bovine milk at species level and to characterize them in reference to presentation, somatic cell count (SCC), bacterial shedding (cfu) and antimicrobial resistance patterns. A total of 200 staphylococcal isolates (S. aureus n = 100; CNS n = 100) originating from aseptically collected quarter milk samples from different quarters of dairy cows were included in the study. They originated from cases of clinical (CM) and subclinical mastitis (SCM) or were isolated from milk with SCC ≤ 100,000 cells/mL in pure culture. We found staphylococci predominantly in cases of SCM (n = 120). In low-SCC cows, 12 S. aureus and 32 CNS isolates were detected. Eighteen percent of each were associated with CM. Eleven CNS species were identified, S. chromogenes (n = 26) and S. xylosus (n = 40) predominated. CNS, particularly those in low-SCC cows, showed higher MIC90 (minimal inhibitory concentration) values for penicillin, ampicillin, cefoperazone, pirlimycin and marbofloxacin. Based on the present results, a careful interpretation of laboratory results is recommended to avoid antimicrobial therapy of staphylococci without clinical relevance and to ensure prudent use of antimicrobials.

A series of 9-substituted 1,2,3,4,5,6,7,8-octahydroacridine-N(10)-oxides is evaluated against 12 bacterial and fungal strains, for their microbicidal and anti-pathogenic features. The largest spectrum of the antibacterial activity is evidenced for the nitro- (2b) and hydroxy- (5b) N -oxides, followed by the amino-N-oxide (3b) . Density functional theory (DFT) modeling of the molecular structure and frontier molecular orbitals, i.e. highest occupied/lowest unoccupied molecular orbital (HOMO/LUMO), is accomplished by using the GAMESS 2012 software at M11/ktzvp level of theory in order to find their structural and electronic parameters. We show that the planarity of the molecules and the presence of the electron withdrawing group are advantages for its antimicrobial activity. Finally, we briefly present and discuss results on the processing of such compounds into thin films and hybrid structures by laser-assisted techniques, i.e. matrix-assisted pulsed laser evaporation (MAPLE) or laser-induced forward transfer (LIFT), to provide simple and environmental friendly, state-of-the-art solutions for antimicrobial/medical coatings and devices. [ABSTRACT FROM AUTHOR]

Eco-friendly, one-pot, solvent-free synthesis of biologically active 2-substituted benzimidazoles is presented and discussed herein. Novel N- Mannich bases are synthesized from benzimidazoles, secondary amines and formaldehyde, and their structures are confirmed by 1 H nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), and elemental analysis. All benzimidazole derivatives are evaluated by qualitative and quantitative methods against 9 bacterial strains. The largest microbicide and anti-biofilm effect is observed for the 2-(1-hydroxyethyl)-compounds. Density functional theory (DFT) modeling of the molecular structure and frontier molecular orbitals, i.e. highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO/LUMO), is accomplished by using the GAMESS 2012 software. Antimicrobial activity is correlated with the electronic parameters (chemical hardness, electronic chemical potential, global electrophilicity index), Mullikan atomic charges and geometric parameters of the benzimidazole compounds. The planarity of the compound, symmetry of the molecule, and the presence of a nucleophilic group, are advantages for a high antimicrobial activity. Finally, we briefly show that further accurate processing of such compounds into thin films and hybrid structures, e.g. by laser ablation matrix-assisted pulsed laser evaporation and/or laser-induced forward transfer, may indeed provide simple and environmental friendly, state-of-the-art solutions for antimicrobial coatings. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides (AMPs) represent an important part of the innate host immune system. Although they are active against a broad range of pathogens, bacteria have evolved different resistance mechanisms to avoid killing by AMPs. Since not much is known about the impact of efflux pumps on the susceptibility of Gram-positive bacteria to AMPs, especially to the cathelicidins, the aim of this study was to analyze whether Staphylococcus aureus can use efflux pumps to resist the antimicrobial effects of cathelicidins derived from different animal species (human, mouse, rabbit or cattle). For this purpose the minimal inhibitory concentrations (MICs) of S. aureus field isolates for the cathelicidins LL-37, mCRAMP, CAP18, BMAP-27 and BMAP-28 in the presence and absence of different efflux pump inhibitors were determined. Furthermore, the MICs of mutants lacking SecDF, a member of the RND efflux pump family, were determined and compared to the MICs of their respective wildtype and complemented strains. The data demonstrated that after blocking RND-type efflux pumps with 1-(1-naphthylmethyl)-piperazine, the MICs for CAP18, but not those for the other cathelicidins tested, were significantly decreased. In good correlation with these data, significantly decreased MICs for CAP18 and also BMAP-27 have been observed for SecDF knockout mutants as compared to their isogenic wildtype strains. In addition, the MIC values increased again after re-introducing a cloned secDF via plasmid complementation. These results indicated an involvement of SecDF in a reduced efficacy of species-specific cathelicidins against S. aureus . [ABSTRACT FROM AUTHOR]

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is an important zoonotic pathogen. An emerging problem in treating S. aureus infections is the increasing resistance against antibiotics. A possible way to overcome this issue is to boost the host immune system and one target are antimicrobial peptides (AMPs), especially cathelicidins. The aim of this study was to characterize the antimicrobial activity of cathelicidins from different animal species against LA-MRSA and to reveal whether major antimicrobial resistance mechanisms influence the bactericidal activity of these peptides. The MICs of 153 LA-MRSA field isolates for different cathelicidins (LL-37, mCRAMP, CAP18, BMAP-27 and BMAP-28) were analysed. The cathelicidin MICs of S. aureus RN4220 and isogenic transformants, that carried 14 functionally active antimicrobial resistance genes, were determined. These resistance genes have been identified in LA-MRSA and specify the resistance mechanisms active efflux, enzymatic inactivation and modification/protection/replacement of target sites. The data showed that mode MIC values for the cathelicidins did not differ among the LA-MRSA isolates of different animal origin. However, distinct differences were detected between the MIC values for the different cathelicidins. MIC values were lowest for bovine cathelicidins (BMAP-27 and BMAP-28) and highest for the human and mouse cathelicidins (LL-37 and mCRAMP). None of the tested antimicrobial resistance genes affected the antimicrobial activity of the cathelicidins. The findings obtained in this study support the hypothesis that cathelicidins might be a promising target to support the host defense against LA-MRSA, especially since the antimicrobial activity of these peptides is not affected by common staphylococcal antimicrobial resistance genes. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the presence of β-lactam-resistant bacteria in six different types of Portuguese cheese. The numbers of ampicillin resistant (AMPr) bacteria varied from 4.7 x 102 to 1.5 x 107 CFU/g. Within 172 randomly selected β-lactam-resistant bacteria, 44 resistant phenotypes were found and 31.4% were multidrug resistant. The majority (85%) of the isolates identified belonged to the Enterobacteriaceae family. The presence of the blaTEM gene was detected in 80.9% of the tested isolates. The results suggest that without thermal processing of the milk and good hygienic practices, cheese may act as a vehicle of transfer of β-lactam-resistant bacteria to the gastrointestinaltract of consumers.

Standard antimicrobial susceptibility tests used to determine bacterial susceptibility to antibiotics are growth dependent and time consuming. The long incubation time required for standard tests may render susceptibility results irrelevant, particularly for patients infected with lethal bacteria that are slow growing on agar but progress rapidly in vivo, such as Yersinia pestis. Here, we present an alternative approach for the rapid determination of antimicrobial susceptibility, based on the quantification of the changes in the expression levels of specific marker genes following exposure to growth-inhibiting concentrations of the antibiotic, using Y. pestis and ciprofloxacin as a model. The marker genes were identified by transcriptomic DNA microarray analysis of the virulent Y. pestis Kimberley53 strain after exposure to specific concentrations of ciprofloxacin for various time periods. We identified several marker genes that were induced following exposure to growth-inhibitory concentrations of ciprofloxacin, and we confirmed the marker expression profiles at additional ciprofloxacin concentrations using quantitative RT-PCR. Eleven candidate marker transcripts were identified, of which four mRNA markers were selected for a rapid quantitative RT-PCR susceptibility test that correctly determined the Minimal Inhibitory Concentration (MIC) values and the categories of susceptibility of several Y. pestis strains and isolates harboring various ciprofloxacin MIC values. The novel molecular susceptibility test requires just 2 h of antibiotic exposure in a 7-h overall test time, in contrast to the 24 h of antibiotic exposure required for a standard microdilution test. [ABSTRACT FROM AUTHOR]

Eight chromium resistant bacteria were isolated from a dry fly ash sample of DVC-MTPS thermal power plant located in Bankura, West Bengal, India. These isolates displayed different degrees of chromate reduction under aerobic conditions. According to 16S rDNA gene analysis, five of them were Staphylococcus, two were Bacillus and one was Micrococcus. The minimum inhibitory concentration towards chromium and the ability to reduce hexavalent chromium to trivalent chromium was highest in Staphylococcus haemolyticus strain HMR17. All the strains were resistant to multiple heavy metals (As, Cu, Cd, Co, Zn, Mn, Pb and Fe) and reduced toxic hexavalent chromium to relatively non toxic trivalent chromium even in the presence of these multiple heavy metals. All of them showed resistance to different antibiotics. In a soil microcosm study, S. haemolyticus strain HMR17 completely reduced 4 mM hexavalent chromium within 7 days of incubation. [ABSTRACT FROM AUTHOR]

Multidrug resistance of heterotrophic bacteria isolated from an aquaculture farm effluent in Parangipettai, at the southeastern coast of India, was investigated. In the initial screening, 27 antibiotic-resistant strains were isolated. All the strains were tested for antibiotic susceptibility against chloramphenicol with varying concentrations. From these, two highly resistant strains, i.e. S1 and S5, were isolated. The selected strains were identified by 16S ribosomal RNA (rRNA) sequencing techniques and confirmed as Bacillus pumilus and Bacillus flexus. Both the antibiotic-resistant strains were further utilized for multidrug susceptibility test by using various antibiotics. These two strains showed antibiotic resistance to 14 of 17 antibiotics tested. Both microdilution assay and well assay methods were used to determine the minimal inhibitory concentration (MIC) for the sensitive strains. Both the tests were shown to be almost similar. Our study highlights the occurrence of multidrug-resistant bacteria in the shrimp farm effluents. [ABSTRACT FROM AUTHOR]

The evolution of drug resistant strains of microbial pathogens provides an urgent need to develop novel therapeutical regimes with resistance-combating capacity. In this study, the phytochemical composition and antibacterial activities of essential oils from Cleome droserifolia and Cleome trinervia growing in Jordan desert were investigated. Hydro-distilled oils were analyzed using GC–MS and evaluated for antibacterial activity in vitro against a selection of Gram-positive and Gram-negative bacteria by the agar-well diffusion and the micro-dilution methods. Sixty five compounds representing 99.3% of the total composition were detected in oil of C . droserifolia , whereas 30 compounds corresponding to 95.9% of the total were detected in oil of C. trinervia . The principal constituents of C . droserifolia oil were (E)-3,7,11-trimethyl-1,6,10-decatrien (11.8%), carotol (10.1%), δ-cadinene (8.9%), β-eudesmol (7.0%) and benzyl isothiocyanate (5.9%). The chief constituents of C. trinervia oil were 1,5-hexandien-3-ol (28.3%), santene (20.0%), 3-methyl-2-methylenebutanitrile (14.9%), Z-myroxide (9.3%) and 3,5-dimethyl-1,2,4-trithiolane (7.0%). The chemical profiles revealed the preponderance of sesquiterpenes (86.6%) and monoterpenes (31.1%) in C. droserifolia and C. trinervia oils, respectively. Appreciable proportions of nitrogen and sulfur-containing compounds were found in the examined oils (8.5% in C. droserifolia and 27.1% in C. trinervia ). Scanning electron microscopy of C . droserifolia and C. trinervia petioles and leaf surfaces showed that the two species are coated with capitate-type glandular hairs consistent with enrichment of such species with essential oils. The antibacterial activity screen study showed that the oils exerted marked growth inhibitory effects. Most bacterial species tested were suppressed, despite the varying degrees of inhibition observed (MIC values of 150–550 μg ml − 1 ). [ABSTRACT FROM AUTHOR]

The biocidal activity of carbonic-acid corrosion inhibitors (CIs) based on fatty acids from different vegetable oils against bacterial cells that catalyze biocorrosion processes was investigated using the bioluminescent method for determining the intracellular ATP concentration. It was shown that all obtained CIs exhibited biocidal activity with the amide complexes of fatty acids being the most effective. Their activity was 4.6-fold higher than the activity of nonamide complexes. The minimal inhibitory concentration that causes the death of all bacterial groups was established for the majority of the CIs to be in the range 100-170 mg/mL, and the best biocidal properties against the oil-oxidizing bacteria of the Pseudomonas genus were observed for the CI prepared from the corn oil (27 mg/mL). [ABSTRACT FROM AUTHOR]