Antibiogram and molecular characterization of extended-spectrum β-lactamase-producing pathogens implicated in chronic suppurative otitis media

Introduction

beta-lactamase-producing bacteria, especially extended-spectrum beta-lactamase (ESBL) producers have strong clinical relevance and have been implicated in chronic suppurative otitis media (CSOM) treatment failures. This study aimed to determine the frequency, antibiogram, and molecular characteristics of ESBL-producing gram-negative bacterial (GNB) pathogens isolated from patients with CSOM.

Methods

three hundred (300) ear swab samples collected from patients with active CSOM were analysed using standard microbiological techniques. Antibiogram of pathogens was determined by Kirby-Bauer disk diffusion technique. Phenotypic detection and molecular characterization of ESBL-producing GNB pathogens were performed by double disk synergy test (DDST) and polymerase chain reaction (PCR).

Results

Escherichia coli and P. aeruginosa were more prevalent among CSOM patients with a duration of discharge >2 weeks. The frequency of ESBL producers among the GNB pathogens was 18.3%. Isolates were generally multidrug-resistant but very susceptible (100% - 70.4%) to ciprofloxacin, imipenem, and amikacin. Multiple antibiotic resistance values of the isolates ranged from 0.7-0.8. Polymerase chain reaction showed that blaSHV (47.6%) was the most predominant ESBL genotype. This was followed by blaTEM (25.2%) and blaCTX-M (10.7%) as the least predominant ESBL gene. Concomitant expression of ESBL gene was observed in 13.6% of the isolates.

Conclusion

this study reported the occurrence and spread of β-lactamase-producing bacteria in patients with CSOM infections. It is therefore very crucial to screen for antibiotic-resistant pathogens at early stages of CSOM infections, for proper antimicrobial therapy and to curb the increasing spread of antimicrobial resistance.

[Comparison of Epsilometer test and agar dilution method in detecting the sensitivity of Helicobacter pylori to metronidazole]

OBJECTIVE

Agar dilution method (ADM) was used as the golden standard to evaluate the consistency of Epsilometer test (E-test) in detecting the sensitivity of Helicobacter pylori (H. pylori) to metronidazole.

METHODS

From August 2018 to July 2020, patients with H. pylori infection treated for the first time in Peking University Third Hospital for gastroscopy due to dyspepsia were included in this study. Gastric mucosas were taken from the patients with H. pylori infection. H. pylori culture was performed. Both the ADM and E-test were applied to the antibiotic susceptibility of H. pylori to metro-nidazole, and the consistency and correlation between the two methods were validated.

RESULTS

In the study, 105 clinical isolates of H. pylori were successfully cultured, and the minimum inhibitory concentration ≥ 8 mg/L was defined as drug resistance. Both ADM and the E-test showed high resistance rates to metronidazole, 64.8% and 62.9%, respectively. Among them, 66 drug-resistant strains were detected by ADM and E-test, and 37 were sensitive strains, so the consistency rate was 98.1%. Two strains were evaluated as drug resistance by ADM, but sensitive by the E-test, with a very major error rate of 1.9%. There was zero strain sensitive according to ADM but assessed as resistant by the E-test, so the major error rate was 0%. Taking ADM as the gold standard, the sensitivity of E-test in the detection of metronidazole susceptibility was 97.1% (95%CI: 0.888-0.995), and the specificity was 100% (95%CI: 0.883-1.000). Cohen's kappa analysis showed substantial agreement, and kappa coefficient was 0.959 (95%CI: 0.902-1.016, P < 0.001). Spearmans correlation analysis confirmed this correlation was significant (r=0.807, P < 0.001). The consistency evaluation of Bland-Altman method indicated that it was good, and there was no measured value outside the consistency interval. In this study, cost analysis, including materials and labor, showed a 32.2% higher cost per analyte for ADM as compared with the E-test (356.6 yuan vs. 269.8 yuan).

CONCLUSION

The susceptibility test of H. pylori to metronidazole by E-test presents better agreement with ADM. Because it is less expensive, less labor intensive, and more rapid, it is an easy and reliable method for H. pylori susceptibility testing.

Anthropic Impact on the Critically Endangered Melanophryniscus admirabilis (Admirable Redbelly Toad): Evidence from the Presence of Multiresistant Enterobacteriaceae

Melanophryniscus admirabilis is a microendemic and critically endangered toad, known from a single population. This microendemic species inhabits a small fragment of the Atlantic Forest in South Brazil, an area significantly impacted by hydroelectric power plant projects, livestock farming, agricultural activities, biopiracy, and tourism. Given the exclusive and limited population of M. admirabilis, preserving and conserving this species is of utmost importance in Brazil. Research on this species primarily concentrates on its biology, ecology, and ecotoxicology. Currently, there is no knowledge about antimicrobial resistance (AMR) bacteria present in wild M. admirabilis, despite the potential for studying them to provide valuable insights into environmental pollution. To this end, Enterobacteriaceae species (n = 82) obtained from 15 wild M. admirabilis toads were subjected to the standard Kirby-Bauer disk diffusion method to test their AMR. The results showed that Enterobacteriaceae species had the highest antibiotic resistance to IPM (45.1%), CIP (39%), NIT (32.5%), AMP (31.3%), TET (18.3%), and FOX (17%). Of the tested species, 18 (21.9%) species tested were susceptible, 40 (48.8%) were resistant to 1 or 2 different antibiotic classes, and 24 (29.3%) were classified as multidrug-resistant. Overall, our findings suggest that the incidence of AMR in Enterobacteriaceae isolated from wild M. admirabilis is high, indicating environmental stress caused by anthropic pollution in their habit.

A modified Kirby-Bauer disc diffusion (mKB) method for accurately testing tigecycline susceptibility: a nation-wide multicenter comparative study

Introduction. Tigecycline is one of the important antibiotics available for treating infection caused by multiple-drug resistant pathogens. However, the conventional AST methods which are commonly used in clinical microbiology laboratories usually lead to false intermediate or resistant results in testing tigecycline susceptibility, and further mislead clinical antimicrobial therapies.Hypothesis. The modified Kirby-Bauer disc diffusion (mKB) method was performed based on the traditional standard Kirby-Bauer disc diffusion (sKB) method.Aim. To evaluate a modified Kirby-Bauer disc diffusion (mKB) method for tigecycline susceptibility testing, for the purpose of providing accurate tigecycline susceptibility results in clinical practice.Methodology. A total of 4271 nonduplicate clinical strains were isolated from 37 hospitals across China to perform the mKB method, standard Kirby-Bauer disc diffusion (sKB) method, comparing with the reference broth microdilution (BMD) according to the CLSI. Parameters of categorical agreement (CA), minor errors (mE), major errors (ME), and very major errors (VME) were used in this methodological evaluation research.Results. BMD testing showed that 91.3-98.9 % of the A. baumannii, K. pneumoniae, E. coli, E. cloacae, S. marcescens, and C. freundii strains were susceptible, while 0-3.1% strains were resistant to tigecycline. When testing A. baumannii, mKB demonstrated higher CA than sKB (90.6 % vs 44.8 %) compared to reference BMD. The mE (9.0 % vs 45.2 %), ME (0.5 % vs 10.6 %) and VME (both 0 %) all satisfied the acceptability criteria. mKB also showed higher CA (87.2 % vs 52.0 %) than sKB in comparison with BMD when testing Enterobacterales (mainly K. pneumonia). The ME (0.45 % vs 8.1 %) and VME (both 0 %) but not mE (12.4 % vs 40.4 %) met the acceptability criteria.Conclusion. The mKB method can test bacterial susceptibility to tigecycline more accurately than sKB. For the tigecycline-intermediate or -resistant strains by sKB method, BMD or mKB method should be used to verify the results and report reliable tigecycline susceptibility results.

An Antimicrobial Fabric Using Nano-Herbal Encapsulation of Essential Oils

Lab coats are widely used in biohazard laboratories and healthcare facilities as protective garments to prevent direct exposure to pathogens, spills, and burns. These cotton-based protective coats provide ideal conditions for microbial growth and attachment sites due to their porous nature, moisture-holding capacity, and retention of warmth from the user's body. Several studies have demonstrated the survival of pathogenic bacteria on hospital garments and lab coats, acting as vectors of microbial transmission. A common approach to fix these problems is the application of antimicrobial agents in textile finishing, but concerns have been raised due to the toxicity and environmental effects of many synthetic chemicals. The ongoing pandemic has also opened a window for the investigation of effective antimicrobials and eco-friendly and toxic-free formulations. This study uses two natural bioactive compounds, carvacrol and thymol, encapsulated in chitosan nanoparticles, which guarantee effective protection against four human pathogens with up to a 4-log reduction (99.99%). These pathogens are frequently detected in lab coats used in biohazard laboratories. The treated fabrics also resisted up to 10 wash cycles with 90% microbial reduction, which is sufficient for the intended use. We made modifications to the existing standard fabric tests to better represent the typical scenarios of lab coat usage. These refinements allow for a more accurate evaluation of the effectiveness of antimicrobial lab coats and for the simulation of the fate of any accidental microbial spills that must be neutralized within a short time. Further studies are recommended to investigate the accumulation of pathogens over time on antimicrobial lab coats compared to regular protective coats.

Sustainable phyto-fabrication of silver nanoparticles using Gmelina arborea exhibit antimicrobial and biofilm inhibition activity

Increase in bacterial resistance to commonly used antibiotics is a major public health concern generating interest in novel antibacterial treatments. Aim of this scientific endeavor was to find an alternative efficient antibacterial agent from non-conventional plant source for human health applications. We used an eco-friendly approach for phyto-fabrication of silver nanoparticles (AgNPs) by utilizing logging residue from timber trees Gmelina arborea (GA). GC-MS analysis of leaves, barks, flowers, fruits, and roots was conducted to determine the bioactive compounds. Biosynthesis, morphological and structural characterization of GA-AgNPs were undertaken by UV-Vis spectroscopy, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometer (XRD). GA-AgNPs were evaluated for antibacterial, antibiofilm, antioxidant, wound healing properties and their toxicity studies were carried out. Results identified the presence of terpenoids, sterols, aliphatic alcohols, aldehydes, and flavonoids in leaves, making leaf extract the ideal choice for phyto-fabrication of silver nanoparticles. The synthesis of GA-AgNPs was confirmed by dark brown colored colloidal solution and spectral absorption peak at 420 nm. Spherical, uniformly dispersed, crystalline GA-AgNPs were 34-40 nm in diameter and stable in solutions at room temperature. Functional groups attributed to the presence of flavonoids, terpenoids, and phenols that acted as reducing and capping agents. Antibacterial potency was confirmed against pathogenic bacteria Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus by disc diffusion assay, MIC and MBC assay, biofilm inhibition assay, electron-microscopy, cell staining and colony counting techniques. The results from zone of inhibition, number of ruptured cells and dead-cell-count analysis confirmed that GA-AgNPs were more effective than GA-extract and their bacteria inhibition activity level increased further when loaded on hydrogel as GA-AgNPs-PF127, making it a novel distinguishing feature. Antioxidant activity was confirmed by the free radical scavenging assays (DPPH and ABTS). Wound healing potential was confirmed by cell scratch assay in human dermal fibroblast cell lines. Cell-proliferation study in human chang liver cell lines and optical microscopic observations confirmed non-toxicity of GA-AgNPs at low doses. Our study concluded that biosynthesized GA-AgNPs had enhanced antibacterial, antibiofilm, antioxidant, and wound healing properties.

Coexistence of ESBL and MBL-mediated resistance in Acinetobacter baumannii in a Tertiary Care Hospital, Bangladesh

Antimicrobial resistance mediated by extended-spectrum beta-lactamases (ESBL), AmpC beta-lactamase and metallo-beta-lactamase (MBL) producing Acinetobacter species is an emerging problem worldwide. In this cross-sectional study total 341 specimens were collected over a period of one year from January 2017 to January 2018. Specimens were collected from ICU and Surgery unit of Mymensingh Medical College Hospital, Mymensingh, Bangladesh. Specimens were collected from ICU and Surgery Unit of Mymensingh Medical College Hospital, Mymensingh, Bangladesh. Samples were processed for culture by standard conventional methods and susceptibility testing and determined by Kirby Bauer disc diffusion method. Antibiotic discs and their strength were according to the CLSI 2017 guideline. Molecular study was done to detect the species by OXA-51 gene and drug resistance genes (IMP, VIM, NDM, TEM, SHV, CTX, SPM, SIM and GIM). Species identification was done by OXA-51 gene which is intrinsic to Acinetobacter baumannii. Among the 46 isolates, 36(78.26%) were positive for Oxa-51 gene, 16(34.8%) for TEM gene, 9(19.6%) for VIM gene, 3(6.5%) for NDM gene and 1(2.2%) for IMP gene. This study gives an alarming sign towards high prevalence of cephalosporin and carbapenem resistance due to production of extended spectrum beta-lactamases and metallo-betalactamases, respectively. Early detection, proper antibiotic policies, and compliance towards infection control practices are the best defenses against these organisms.

In vitro efficacy of Azadirachta indica leaf extract against methicillin resistant Staphylococci isolated from skin infection

In this cross-sectional study, the isolation and identification of Methicillin Resistant Staphylococcus aureus (MRSA) and Methicillin Resistant S. epidermidis (MRSE) was described from skin infections (n=100). Initial isolation was done by conventional procedures followed by amplification/ sequence analysis of 16S rRNA. Methicillin resistance was determined using cefoxitin discs and resistant isolates were screened for mec-A gene followed by Minimum Inhibitory Concentrations (MIC) determination of vancomycin. In second phase, we investigated extract of Azadirachta indica leaves using Fourier Transformed Infrared Spectroscopy (FTIR-Spectroscopy) and investigated in vitro activity. Initially, total of 28 Staphylococci were identified. 16S rRNA gene sequence confirmed S. aureus (22), S. epidermidis (3) and S. saprophyticus (3) isolates. Cefoxitin discs showed (7/22) MRSA, (3/3) (MRSE) and none of the methicillin resistant S. saprophyticus. MRSA and MRSE isolates showed presence of mec-A gene. However, all isolates were sensitive to vancomycin MIC (0.5-2μg/mL) and sensitive to Linezolid. FTIR-Spectroscopy of A. indica indicated the presence of azadirachtin and nimbolinin. The mean zone of inhibition was measured 14.23±1.37 and 13.66±0.70 against MRSA and MRSE isolates, respectively. Altogether, MRSA and MRSE is significant public health concern. However, vancomycin and linezolid were found effective and extract of A. indica showed in vitro effects.

Exploring the antifungal activity and mechanism of action of Zingiberaceae rhizome extracts against Malassezia furfur

ETHNOPHARMACOLOGICAL RELEVANCE

Rhizomes from members of Zingiberaceae have long been used in Thai traditional medicine to treat cutaneous fungal infections, including Malassezia-related skin disorders. Alpinia galanga, Curcuma longa, Zingiber cassumunar, and Zingiber officinale are particularly popular in folk remedies.

AIM OF THE STUDY

On account of the application background in traditional medicine, the present study aims to screen and determine the composition and possible mechanism of the rhizome extracts of selected Zingiberaceae and corresponding fractions against M. furfur.

MATERIALS AND METHODS

All solvent extracts (ethanol, methanol, and n-hexane) obtained from each plant were screened for anti-Malassezia activity by agar disc diffusion assay. The MIC and MFC values of the potent rhizome extract and its bioactive fraction isolated by TLC were determined using broth dilution assay followed by chemical characterization using GC-MS. The anti-Malassezia mechanism was investigated by macroscopic and microscopic observation of cells grown in the yeast phase and hyphal phase.

RESULTS

The primary screening results showed that the n-hexane extract from A. galanga possessed the most significant anti-Malassezia activity. The MIC and MFC values of this extract were in a range of 0.04-0.08 mg/mL and 0.04-0.16 mg/mL, respectively. The TLC purification of the n-hexane extract from A. galanga gave a total of nine fractions, of which only a single exhibited anti-Malassezia activity. The GC-MS analysis of the rhizome extract and the derivative fraction revealed that the major constituents were (2,6-dimethylphenyl)borate followed by a trace content of 1,8-cineol and hydrocarbons. For the antifungal mechanism of the fraction, treatments of the fraction led to morphological changes in cell size and shape, exerted massive vacuoles in yeast form, and inhibited the transition to hyphae but not likely affected chitin contents of the cell wall of M. furfur.

CONCLUSIONS

According to the results, the n-hexane extract of A. galanga rhizome exhibits promising anti-Malassezia potential. The inhibitory effect on virulent hyphal growth supports that A. galanga is a valuable source of natural antifungal agents for further pharmaceutical research.

Anticancer, Enhanced Antibacterial, and Free Radical Scavenging Potential of Fucoidan- (Fucus vesiculosus Source) Mediated Silver Nanoparticles

The present research displays the green synthesis of stable silver nanoparticles (AgNPs). The aqueous solution of Fucoidan from Fucus vesiculosus source (brown marine algae) is used as a reducing and capping agent. UV-Vis spectroscopy, XRD, FT-IR, SEM, EDX, and TEM with selected area electron diffraction are used to characterize the synthesized silver nanoparticles (AgNPs). The synthesized AgNPs exhibit a surface plasmon resonance at 430 nm after 24 h. The characterization results showed that AgNPs are crystalline in nature and exhibit mostly spherical shapes with an average diameter of 4-45 nm. Silver nanoparticles showed effective antibacterial activity against representative pathogens of bacteria. The activities of commercial antibiotics were enhanced by impregnation with the synthesized AgNPs. It also shows good fungicidal and anticancer activity against liver and lung cell lines and shows significant antioxidant efficacy (84%) at 10 μg/ml AgNP concentration against DPPH. The utilization of environmentally synthesized AgNPs offers numerous benefits of ecofriendliness and compatibility for biomedical applications.

Comparative study of cefixime and tetracycline as an evaluation policy driven by the antibiotic resistance crisis in Indonesia

Antibiotic resistance is a serious threat that occurs globally in the health sector due to increased consumption of inappropriate antibiotics. Guidelines for prescribing antibiotics for ARTIs have been issued in general practice to promote rational antibiotic prescribing. This study was conducted to compare the effectiveness of cefixime and tetracycline as a solution to improve monitoring of appropriate antibiotic use in the treatment of ARTIs. All stock isolates were rejuvenated first, and cultured on standard media and Kirby-Bauer disc diffusion method was used for susceptibility testing in accordance with the Clinical and Laboratory Standard Institute's (CLSI) recommendations. Identification of bacteria from a single isolate was carried out to determine which bacteria were resistant to cefixime and tetracycline. A total of 466 single isolates of bacteria were analyzed, which showed a percentage of resistance to cefixime 38.0%, and tetracycline 92.86%. Bacterial isolates were resistant to cefixime and tetracycilne was a genus of Haemophilus, Streptococcus, Corynebacterium, Staphylococcus, and bordetella. Cefixime compared to tetracycline was proven to be superior in terms of the effectiveness of ARIs treatment.

High Proportion of Oxacillin-Susceptible mecA-Positive Staphylococcus aureus Isolates from Post-Viral Acute Rhinosinusitis Patients

&lt;b&gt;Background and Objective:&lt;/b&gt; Detection of methicillin-resistant&lt;i&gt; S. aureus&lt;/i&gt; have become a challenge in the presence of oxacillin-susceptible and &lt;i&gt;mecA&lt;/i&gt;-positive &lt;i&gt;S. aureus &lt;/i&gt;(OS-MRSA), concerning the misidentification events and therapeutic implications. This study aims to identify the OS-MRSA in clinical isolates of Post-viral acute rhinosinusitis, which, hopefully, can interfere with the therapeutic strategy. &lt;b&gt;Materials and Methods:&lt;/b&gt; There were 60 patients diagnosed with Post-viral acute rhinosinusitis, recruited from an Ear, Nose and Throat (ENT) outpatient clinic. &lt;i&gt;Staphylococcus aureus&lt;/i&gt; isolates were identified from the culture and were then tested for antibiotics susceptibility using a Kirby-Bauer disc diffusion test. The &lt;i&gt;mecA&lt;/i&gt;, &lt;i&gt;mecC&lt;/i&gt; and &lt;i&gt;blaZ&lt;/i&gt; genes were determined using the Polymerase Chain Reaction (PCR) method. &lt;b&gt;Results:&lt;/b&gt; &lt;i&gt;Staphylococcus aureus &lt;/i&gt;was identified in 20 of the 60 samples from the patients (33.3%; 95% CI: 21.0-45.6). Of the 20 isolates, 19 isolates (95%) had a positive &lt;i&gt;mecA&lt;/i&gt; gene, 19 (95%) had a positive &lt;i&gt;mecC&lt;/i&gt; gene and 20 (100.0%) had a positive &lt;i&gt;blaZ &lt;/i&gt;gene. The majority of the &lt;i&gt;mecA&lt;/i&gt;-positive &lt;i&gt;S. aureus&lt;/i&gt; showed an oxacillin-susceptible (85%) and 3 isolates (15.0%) were oxacillin-resistant toward the &lt;i&gt;S. aureus&lt;/i&gt;. &lt;b&gt;Conclusion:&lt;/b&gt; There was a high proportion of Oxacillin/cefoxitin-Susceptible &lt;i&gt;mecA&lt;/i&gt;-positive &lt;i&gt;S. aureus&lt;/i&gt; in the study population that indicate phenotypic susceptibility to antibiotics does not always indicate the absence of genes that carry resistant traits, thus allowing misidentification if the only phenotypic examination is carried out.

Comparison of Etest and broth microdilution for evaluating the susceptibility of Staphylococcus aureus and Streptococcus pneumoniae to ceftaroline and of carbapenem-resistant Enterobacterales and Pseudomonas aeruginosa to ceftazidime/avibactam

OBJECTIVES

Decreased susceptibility to ceftazidime/avibactam (CZA) and ceftaroline (CPT) has been reported during antimicrobial resistance surveillance and therapy. Conventional laboratories are unable to provide timely susceptibility testing for CZA and CPT because these antimicrobial agents are not incorporated in automated susceptibility testing systems.

METHODS

We evaluated Etest and the Sensititre broth microdilution (BMD) method for testing CZA against carbapenem-resistant Gram-negative bacilli and CPT against important Gram-positive cocci bloodstream isolates. Genotypes of carbapenemases in Enterobacterales were also determined using the Xpert® Carba-R assay.

RESULTS

Etest showed ≥90% agreement with Sensititre BMD for carbapenem-resistant Klebsiella pneumoniae (CRKP) (n = 187), carbapenem-resistant Escherichia coli (CREC) (n = 28) and Streptococcus pneumoniae (n = 35); however, the very major error rate exceeded 3%. Agreement between Etest and Sensititre BMD was <90% for carbapenem-resistant Pseudomonas aeruginosa (CRPA) (n = 81), methicillin-susceptible Staphylococcus aureus (MSSA) (n = 92) and methicillin-resistant S. aureus (MRSA) (n = 170). Both agents remained potent with a high susceptibility rate by Sensititre BMD as follows: CZA against CRKP (95.0%), CREC (89.3%) and CRPA (84.5%); and CPT against MSSA (100.0%), MRSA (95.3%) and S. pneumoniae (94.3%). CZA was active against blaKPC-carrying CRKP (98.5% susceptible), and resistance in the majority of CZA-resistant Enterobacterales isolates (6 of 10 CRKP and 2 of 3 CREC) was due to the presence of a metallo-β-lactamase gene.

CONCLUSION

Our results suggest that interpretation of susceptibility results obtained by Etest for both agents should be undertaken cautiously and remains challenging.

Antimicrobial Face Shield: Next Generation of Facial Protective Equipment against SARS-CoV-2 and Multidrug-Resistant Bacteria

Transparent materials used for facial protection equipment provide protection against microbial infections caused by viruses and bacteria, including multidrug-resistant strains. However, transparent materials used for this type of application are made of materials that do not possess antimicrobial activity. They just avoid direct contact between the person and the biological agent. Therefore, healthy people can become infected through contact of the contaminated material surfaces and this equipment constitute an increasing source of infectious biological waste. Furthermore, infected people can transmit microbial infections easily because the protective equipment do not inactivate the microbial load generated while breathing, sneezing or coughing. In this regard, the goal of this work consisted of fabricating a transparent face shield with intrinsic antimicrobial activity that could provide extra-protection against infectious agents and reduce the generation of infectious waste. Thus, a single-use transparent antimicrobial face shield composed of polyethylene terephthalate and an antimicrobial coating of benzalkonium chloride has been developed for the next generation of facial protective equipment. The antimicrobial coating was analyzed by atomic force microscopy and field emission scanning electron microscopy with elemental analysis. This is the first facial transparent protective material capable of inactivating enveloped viruses such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in less than one minute of contact, and the methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis. Bacterial infections contribute to severe pneumonia associated with the SARS-CoV-2 infection, and their resistance to antibiotics is increasing. Our extra protective broad-spectrum antimicrobial composite material could also be applied for the fabrication of other facial protective tools such as such as goggles, helmets, plastic masks and space separation screens used for counters or vehicles. This low-cost technology would be very useful to combat the current pandemic and protect health care workers from multidrug-resistant infections in developed and underdeveloped countries.

A comparison of E. coli susceptibility for amoxicillin/clavulanic acid according to EUCAST and CLSI guidelines

In our tertiary care center, the reported susceptibility of E. coli blood isolates to amoxicillin/clavulanic acid exceeded 90% in 2005 and showed a progressive decrease to 50% by 2017. In this study, we investigate whether there is a real increase in resistant E. coli strains or if this apparent decline in reported susceptibility might be attributed to the substitution of CLSI by EUCAST guidelines in 2014. We randomly selected 237 E. coli blood isolates (stored at - 80 °C) from 1985 to 2018 and reassessed their MIC values, applying both the CLSI (fixed ratio of clavulanic acid) and EUCAST guidelines (fixed concentration of clavulanic acid). In parallel, the susceptibility of these isolates was retested by disk diffusion, according to the EUCAST guidelines. Whole genome sequencing was successfully performed on 233 of the 237 isolates. In only 130 of the 237 isolates (55.0%), testing according to the EUCAST and CLSI criteria delivered identical MIC values for amoxicillin/clavulanic acid. In 64 of the 237 isolates (27.0%), the MIC values diverged one dilution; in 38 (16.0%), two dilutions; and in five (2.1%), three dilutions. From these 107 discrepant results, testing according to EUCAST methodology revealed more resistant profiles in 93 E. coli strains (94.1%). Also, phenotypical susceptibility testing according to EUCAST guidelines tends to correlate better with the presence of beta-lactamase genes compared to CLSI testing procedure. This study highlights the low agreement between EUCAST and CLSI methodologies when performing MIC testing of amoxicillin/clavulanic acid. More strains are categorized as resistant when EUCAST guidelines are applied. The low agreement between EUCAST and CLSI was confirmed by WGS, since most of EUCAST resistant/CLSI sensitive isolates harbored beta-lactamase genes.

Antibacterial, antifungal and enzymatic activities of azithromycin-heavy metal complexes: Newly synthesized and characterized

As part of our continuous research to understand the interaction mechanism of drug and metallo-elements, heavy metal complexes of azithromycin (AZI) were synthesized with arsenic oxide, lead carbonate and silver chloride salts in molar ratio of 2: 1 (L: M). Synthesized heavy metal complexes have shown good percent yield and characterized through spectroscopic parameters including UV-Visible, TLC, FT-IR, NMR and elemental analysis (CHN). Spectroscopic characterization reveals the binding of ligand AZI with heavy metals in bi-dentate manner involving the hydroxide and 9a-NCH₃ group of the aglycone ring of AZI. These newly synthesized heavy metal complexes were evaluated for their antimicrobial response against selected gram positive and gram negative organisms and antifungal species. It was noted that all newly synthesized complexes exhibits increased activity against B.subtilus whereas, AZI itself didn't show any activity, while synthesized complexes have low to moderate response against all the studied organisms. Complex A-M12 possess greater enzymatic response against both urease and alpha chymotrypsin among all the studied complexes. Results obtained were then statistically analyzed through one way ANOVA and Dunnett's test by using SPSS version 20.0 suggesting the significant response of complexes against selected organisms.

GC-MS profiling and in vitro antioxidant, cytotoxic and antimicrobial activities of Trianthema triquetra Rottl. ex Willed

Trianthema triquetra Rottl. ex Willed is being used as a herbal remedy for various diseases in India and Pakistan. Still, no scientific data is available about therapeutic potential and phytochemistry of the plant. The aim of the current investigation is to perform GC-MS analysis, antioxidant (total phenolic and flavonoid content, DPPH assay), antimicrobial (disc diffusion assay) and cytotoxic (XTT and RBC's cellular membrane protection assay) studies. Methanolic extract and its fractions (n-hexane, ethyl-acetate, chloroform, n-butanol and water) were investigated for in vitro studies. Results showed that n-butanol fraction exhibited a significant (p<0.05) antioxidant potential (IC50=63.35±0.13 μg/mL) and also possess highest phenolic content (177±4.36 mg/g GAE). Whereas, n-hexane fraction showed highest flavonoid content (14.67±1.53 mg/g QE). 2, 4-Ditert-butyl-6-nitrophenol (26.79%) and Squalene (25.64%) were detected as major components through GC-MS analysis of chloroform fraction, eluted from column chromatography. Moreover, chloroform fraction also exhibited antimicrobial potential. Significant (p<0.05) dose dependent inhibition response on cell growth against CCRF-CEM cell lines was exhibited by methanolic extract. Furthermore, hemolytic potential of methanolic extract was found to be in safe range (2.23%-6.37%). So, it can be inferred that Trianthema triquetra can be exploited as an alternative remedy for cancer, oxidative stress related disorders and various skin diseases.

Phytochemical analysis, antioxidant and antibacterial potential of some selected medicinal plants traditionally utilized for the management of urinary tract infection

Recent studies on prevalence of urinary tract infection indicate that approximately one third population of the world has been suffering from this disease. The current study was designed to evaluate the antibacterial activity of aqueous-ethanolic extracts (30/70) of Tribulus terrestris (TT), Vaccinium macrocarpon (VM), Cuminum cyminum (CC), Rheum emodi (RE), Piper cubeba (PC) and their compound formulation "Crano-cure" against Escherichia coli, Klebsiella pneumonia, Staphylococcus saprophyticus and Proteus mirabilis through disc diffusion method and agar well methods compared with standard Ciprofloxacin. DPPH radical scavenging methods were applied for antioxidant activities and phytochemical analysis was also performed to detect the phytoconstituents. All the plants exhibited potent antibacterial strength while Crano-cure showed most potent results comparable with that of standard drug. The zone of inhibition produced by disk diffusion test was 26±0.34, 26±0.75, 26±0.00, 18±0.64, 22.5±0.52, 29±0.39, 32±0.00 mm and for agar well diffusion test 23±0.67, 22±0.46, 23±0.77, 20±0.00, 22±0.46, 24±0.52, 33±0.00 mm against Tribulus terrestris, Cuminum cyminum, Rheum emodi, Piper cubeba, Vaccinium macrocarpon, crano-cure and ciprofloxacin. Similarly, percentage inhibition for antioxidant potential was 78.74, 24.57, 58.75, 20.23, 88.88, 90.12 and 92.35 respectively. The tested plants exhibited remarkable antibacterial and antioxidant activities.

QSAR Models for Active Substances against Pseudomonas aeruginosa Using Disk-Diffusion Test Data

Pseudomonas aeruginosa is a Gram-negative bacillus included among the six “ESKAPE” microbial species with an outstanding ability to “escape” currently used antibiotics and developing new antibiotics against it is of the highest priority. Whereas minimum inhibitory concentration (MIC) values against Pseudomonas aeruginosa have been used previously for QSAR model development, disk diffusion results (inhibition zones) have not been apparently used for this purpose in the literature and we decided to explore their use in this sense. We developed multiple QSAR methods using several machine learning algorithms (support vector classifier, K nearest neighbors, random forest classifier, decision tree classifier, AdaBoost classifier, logistic regression and naïve Bayes classifier). We used four sets of molecular descriptors and fingerprints and three different methods of data balancing, together with the “native” data set. In total, 32 models were built for each set of descriptors or fingerprint and balancing method, of which 28 were selected and stacked to create meta-models. In terms of balanced accuracy, the best performance was provided by KNN, logistic regression and decision tree classifier, but the ensemble method had slightly superior results in nested cross-validation.

Evaluation of antioxidant, antimicrobial and anticancer activities of compounds reported Saussurea hypoleuca Spreng. roots

Current study was intended to isolate bioactive compounds from ethyl acetate fraction of Saussurea hypoleuca root extract and evaluation of their antioxidant, antimicrobial and anti-cancerous activities which might be helpful for their chemo preventive potential against selected bacterial strains. Column chromatography was done for isolation of compounds which were characterized on the basis of extensive spectroscopic analysis; Infra-red (IR), Electron Ionization (EI-Positive), Proton Nuclear Magnetic Resonance (¹H-NMR) and Carbon Nuclear Magnetic Resonance (¹³C-NMR). Two compounds were identified, as sesquiterpenes (40mg) and linoleic acid (33mg) from 10 grams of ethyl acetate fraction. Both compounds have shown in vitro antioxidant activity which in regard; 2, 2- diphenyl-1-picrylhydrazyl (DPPH) scavenging potential was high in sesquiterpenes (261.81) as compared to linoleic acid (90.89). The minimum inhibitory concentrations (MIC) of both compounds were evaluated in various bacterial and fungal strains against respective controls. However, in human hepatocellular carcinoma (Hep G2 cell lines) sesquiterpenes exhibited strong anticancer potential than linolenic acid which might be its potential free radical inactivator in MTT assay. This paper directs the ethano medicinal worth of plant root as it possesses bioactive compounds which in our best knowledge these compounds isolated and reported first time from this plant root specie.

Smaller Copper Oxide Nanoparticles have More Biological Effects Versus Breast Cancer and Nosocomial Infections Bacteria

BACKGROUND AND OBJECTIVES

Despite promising successes in developing new drugs and pharmaceutical biotechnology, infectious diseases and cancer are still the principal causes of mortality and morbidity globally. Therefore, finding effective ways to deal with these pathogens and cancers is critical. Metal nanoparticles are one of the new strategies to combat bacteria and cancers.

METHODS

We examined the antimicrobial activity of 30 and 60 nm copper oxide nanoparticles (CuO-NPs) against Acinetobacter baumannii and Staphylococcus epidermidis bacteria responsible for nosocomial infections in standard and clinical strains and anti-cancer activity against 4T1 cell line as malignancy breast cancer cells. Synthesis of CuO-NPs was performed by a one-step reduction method and confirmed by DLS and TEM microscopy at 30 and 60 nm sizes. The antibacterial and anti-cancer activities of the nanoparticles were then investigated against the aforementioned bacteria and breast cancer.

RESULTS

Using disk, well, MIC, MBC methods, and viability/bacterial growth assay, 30 nm CuO NPs were found to have more antibacterial activity on standard and clinical strains than 60 nm CuO NPs. On the other hand, using MTT, apoptosis, and gene expression method, 30 nm nanoparticles were found to have more anti-cancer potential than 60 nm CuO NPs.

CONCLUSIONS

Our findings implicate CuO-NPs to possess antimicrobial and anti-cancer effects and more significant potential in smaller sizes, suggesting their pharmaceutical and biomedical capacity.
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Mycorrhizal inoculation impact on Acorus calamus L. - An ethnomedicinal plant of western Himalaya and its in silico studies for anti-inflammatory potential

ETHNOPHARMACOLOGICAL RELEVANCE

Different plants are used for the treatment of various ailments and Acorus calamus L. is one such plant found in Western Himalaya. Rhizome of this plants has ethnomedicinal significance, as its rhizome is used for curing fever, pain and inflammation. An attempt has been made to alter the phytochemicals and increase its antioxidant property in a sustainable way with the help of mycorrhizal inoculation.

AIM OF THE STUDY

Study of mycorrhizal (Funneliformis mosseae) impact on the biological activities and phytochemical profile of A. calamus L. rhizome and in silico studies of phytochemicals for their anti-inflammatory property.

MATERIALS AND METHODS

F. mosseae was mass multiplied by single spore culture and then A. calamus rhizomes were inoculated with it. Antioxidant potential of rhizome extract was observed by DPPH and FRAP assays and the phytochemical profiling was done with GC-MS analysis. For observing antimicrobial activity disc diffusion method was employed. Dominant phytochemicals α-asarone and monolinolein TMS were chosen for molecular docking studies against four receptors (4COX, 2AZ5, 5I1B, 1ALU).

RESULTS

There was increase in antioxidant activity of rhizome extract after mycorrhizal inoculation. However, no change in antimicrobial activity was observed in the plant after mycorrhizal inoculation. The comparison in phytochemicals was observed by GC-MS analysis which showed qualitative and quantitative variation in biochemical content in plants. The phytochemical, α-asarone and monolinolein TMS showed highest docking score and least binding energy against 1ALU and 4COX respectively for anti-inflammatory activity.

CONCLUSION

Medicinal plants are potential source of antioxidants which can be increased by mycorrhizal inoculation without addition of chemical fertilizers and also results in altering the phytochemical composition.

In Vitro and In Vivo Antibacterial Activity of Gliotoxin Alone and in Combination with Antibiotics against Staphylococcus aureus

Multidrug-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) is one of the major causes of hospital-acquired and community infections and pose a challenge to the human health care system. Therefore, it is important to find new drugs that show activity against these bacteria, both in monotherapy and in combination with other antimicrobial drugs. Gliotoxin (GT) is a mycotoxin produced by Aspergillus fumigatus and other fungi of the Aspergillus genus. Some evidence suggests that GT shows antimicrobial activity against S. aureus in vitro, albeit its efficacy against multidrug-resistant strains such as MRSA or vancomycin-intermediate S. aureus (VISA) strainsis not known. This work aimed to evaluate the antibiotic efficacy of GT as monotherapy or in combination with other therapeutics against MRSA in vitro and in vivo using a Caenorhabditis elegans infection model.

A New Potential Source of Anti-pathogenic Bacterial Substances from Zamioculcas zamiifolia (Lodd.) Engl. Extracts

BACKGROUND AND OBJECTIVE

The increase of antibiotic-resistant bacteria is a problem for global health that needs to find new antibiotic drugs. The plant is the potential source of antibiotic substances that important to solve the antibiotic-resistant bacteria. This study was aimed to evaluate the antibacterial activity of Zamioculcas zamiifolia stem extracts against nine human pathogenic bacteria.

MATERIALS AND METHODS

Z. zamiifolia stems were extracted with five extraction solvents. The screening of antibacterial activity of stem extract was measured using agar disc diffusion assay. The Minimal Inhibition Concentration (MIC) and Minimal Bactericidal Concentration (MBC) values of extracts were determined using the broth microdilution assay and colorimetric assay.

RESULTS

The results indicated that the lowest MIC value of 0.09 mg mL-1 against Staphylococcus aureus TISTR 1466 was obtained from hexane extraction. The lowest MBCs value of 1.56 mg mL-1 against Bacillus cereus TISTR 2373, Listeria spp. and Escherichia coli TISTR 527 were obtained from ethanol and methanol extractions.

CONCLUSION

The ethanolic and methanolic stem extracts of Z. zamiifolia demonstrated the highest anti-human pathogenic bacterial activity. This is the first report to demonstrate the high potential of antibacterial substance from Z. zamiifolia stem extracts, which can be developed further as a natural drug for treating bacterial infectious diseases.

Evaluation of the Antibacterial Activity of <i>Spathiphyllum wallisii</i> Extracts Against Human Pathogenic Bacteria

BACKGROUND AND OBJECTIVE

The urgent of finding new antibiotics due to the rising of antibiotic-resistant bacteria. The plant is the main source of new antibiotic substances. The purpose of this research was to evaluate the antibacterial activity of Spathiphyllum wallisii extracts against nine human pathogenic bacteria.

MATERIALS AND METHODS

The stalks, leaf, rhizome and root of S. wallisii were extracted by using hexane, dichloromethane, ethyl acetate, ethanol and methanol. The disc diffusion assay was used to screen the antibacterial activity of S. wallisii extracts. Broth dilution and colorimetric assay were used to determine the Minimal inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) values of extracts.

RESULTS

The lowest MIC values at 0.048 mg mL-1 were presented in the stalks extract with dichloromethane, ethyl acetate, methanol and ethanol against B. subtilis TISTR 008, the leaf extracted with hexane, dichloromethane, ethyl acetate, methanol and ethanol against B. subtilis TISTR 008; the leaf extracted with ethyl acetate, methanol and ethanol against S. aureus TISTR 1466, the leaf extracted with dichloromethane, ethyl acetate, methanol and ethanol against S. aureus PK; the rhizome extracted with methanol against S. aureus PK. The lowest of MBC value of 0.048 mg mL-1 was obtained from methanolic rhizome extract against B. subtilis TISTR 008.

CONCLUSION

The methanolic rhizome extract of S. wallisii demonstrated the highest of pathogenic bacterial growth inhibition. This is the first report about the antibacterial activity of S. wallisii extracts that will add new information in natural drug discovery and development in industrial pharmacology.

Comparative analysis of virulence determinants, phylogroups, and antibiotic susceptibility patterns of typical versus atypical Enteroaggregative E. coli in India

Enteroaggregative Escherichia coli (EAEC) is an evolving enteric pathogen that causes acute and chronic diarrhea in developed and industrialized nations in children. EAEC epidemiology and the importance of atypical EAEC (aEAEC) isolation in childhood diarrhea are not well documented in the Indian setting. A comparative analysis was undertaken to evaluate virulence, phylogeny, and antibiotic sensitivity among typical tEAEC versus aEAEC. A total of 171 EAEC isolates were extracted from a broad surveillance sample of diarrheal (N = 1210) and healthy children (N = 550) across North India. Polymerase chain reaction (PCR) for the aggR gene (master regulator gene) was conducted to differentiate tEAEC and aEAEC. For 21 virulence genes, we used multiplex PCR to classify possible virulence factors among these strains. Phylogenetic classes were identified by a multiplex PCR for chuA, yjaA, and a cryptic DNA fragment, TspE4C2. Antibiotic susceptibility was conducted by the disc diffusion method as per CLSI guidelines. EAEC was associated with moderate to severe diarrhea in children. The prevalence of EAEC infection (11.4%) was higher than any other DEC group (p = 0.002). tEAEC occurrence in the diarrheal group was higher than in the control group (p = 0.0001). tEAEC strain harbored more virulence genes than aEAEC. astA, aap, and aggR genes were most frequently found in the EAEC from the diarrheal population. Within tEAEC, this gene combination was present in more than 50% of strains. Also, 75.8% of EAEC strains were multidrug-resistant (MDR). Phylogroup D (43.9%) and B1 (39.4%) were most prevalent in the diarrheal and control group, respectively. Genetic analysis revealed EAEC variability; the comparison of tEAEC and aEAEC allowed us to better understand the EAEC virulence repertoire. Further microbiological and epidemiological research is required to examine the pathogenicity of not only typical but also atypical EAEC.

Enteroaggregative E. coli (EAEC) are an increasingly important cause of diarrhea. E. coli belonging to this category cause watery diarrhea, which is often persistent and can be inflammatory. It is also associated with traveler’s diarrhea in children and adults in middle and high-income countries. EAEC are defined by their ability to adhere to epithelial cells in a characteristic stacked brick-like pattern. However, the identification of these pathogenic strains remains elusive because of its heterogeneous nature. Genes that could contribute to the pathogenicity of EAEC encode adhesions, toxins, and other factors. Due to the heterogeneity of EAEC strains and differing host immune responses, not all EAEC infections are symptomatic. A critical factor in both recognizing EAEC pathogenesis and defining typical EAEC (tEAEC) strains is AggR, a transcriptional control for many EAEC virulence genes. The central role of aggR in virulence confers a strong priority to understand its pathogenicity. To identify EAEC, the CVD432 probe has been used. The CVD432 is a DNA probe from pAA plasmid of EAEC, has been reported to be specific for the detection of EAEC. The lack of sensitivity comes from the genetic heterogeneity of the EAEC strains and the wide geographic dispersal of strains. In our study, we performed a large surveillance of EAEC from North India among the pediatric population. Samples were collected by the microbiology staff at the Postgraduate Institute of Medical Education and Research (PGIMER) and referral system labs in Chandigarh (Manimajra), Punjab (Ludhiana), Haryana (Panchkula and Ambala Cantt), Himachal Pradesh (Hamirpur, Shimla, and Tanda), and Uttarakhand (Rishikesh, Rudrapur, and Haridwar)]. PGIMER is the largest tertiary care hospital in North India and serves patients from across Punjab, Jammu and Kashmir, Himachal Pradesh and Haryana. EAEC infections were detected using molecular methods. In our finding, astA, aap, and aggR genes were most frequently found in the EAEC from the diarrheal population. Within tEAEC, this gene combination is present in more than 50% of strains and helps to differentiate tEAEC from aEAEC. Our collection of EAEC strains helps in finding an appropriate marker for the early detection of EAEC. Our signature sequence (astA, aap, and aggR) will be ideal as focus genes for EAEC identification, as well as tEAEC and aEAEC. The multidrug resistance (MDR) was observed in 75.8% of the EAEC strains. tEAEC exhibits resistance to a greater number of antibiotics with respect to aEAEC. The phylogenetic analysis revealed that EAEC phylogeny is diverse and dispersed in all the phylogroups.

Extended-spectrum Beta-lactamase and AmpC beta-lactamases producing gram negative bacilli isolated from clinical specimens at International Clinical Laboratories, Addis Ababa, Ethiopia

BACKGROUND

Extended spectrum Beta-lactamases (ESBLs) and AmpC beta-lactamases (AmpC) are the common enzymes produced by gram negative bacilli, which are their main mechanisms of resistance to all generations of cephalosporins. Hence, this study aimed to determine the magnitude of ESBLs and AmpC producing gram negative bacilli (GNB) isolated from clinical specimens at International clinical Laboratories in Addis Ababa, Ethiopia.

METHODS

A cross sectional study was conducted from January to May 2018. From different clinical specimens, 338 GNB were isolated and characterized. Bacterial species identification, antimicrobial susceptibility testing and screening for ESBLs and AmpC production were performed using Phoenix automated system (BD phoenix100). ESBLs production was confirmed using a combination disc method. All Cefoxitin resistant and confirmed ESBLs producing GNB were confirmed for AmpC beta-lactamases production by AmpC confirmatory Neo-Sensitabs discs (ROSCO tablet). Data were analyzed using SPSS version 20 software.

RESULTS

E. coli 66.0% (224/338) followed by K. pneumoniae 12.1% (41/338) were GNB most frequently isolated. The overall magnitude of ESBLs producing GNB was 38.8% (131/338) and the extent of AmpC beta-lactamase producing GNB was 2.4% (8/338). Majority of ESBLs and AmpC beta-lactamases producing GNB were isolated from urine specimens 47.5% (116/338). Ampicillin (75.4%), amoxicillin with clavulanic acid (64.0%) and sulfamethoxazole-trimethoprim (55.6%) were most the antibiotics to which resistance was most commonly found. The multidrug resistance (MDR) level of GNB was 74.0% (250/338). Of ESBLs and AmpC beta-lactamases producing GNB, 99.3% were MDR (p < 0.05).

CONCLUSION

The high magnitude of ESBLs and AmpC beta-lactamases producing GNB calls the needs of strong intervention to minimize further occurrence and spread of such GNB. More importantly, the MDR level was high which suggests continuous monitoring & reviewing of antimicrobial policy in hospitals and the country at large.

Molecular characterization of invasive Enterobacteriaceae from pediatric patients in Central and Northwestern Nigeria

Background

Bacteremia is a leading cause of mortality in developing countries, however, etiologic evaluation is infrequent and empiric antibiotic use not evidence-based. Here, we evaluated the patterns of ESBL resistance in children enrolled into a surveillance study for community acquired bacteremic syndromes across health facilities in Central and Northwestern Nigeria.

Method

Blood culture was performed for children aged less than 5 years suspected of having sepsis from Sept 2008-Dec 2016. Blood was incubated using the BACTEC^00AE system and Enterobacteriacea identified to the species level using Analytical Profile Index (API20E^®). Antibiotic susceptibility profile was determined by the disc diffusion method. Real time PCR was used to characterize genes responsible for ESBL production.

Result

Of 21,000 children screened from Sept 2008-Dec 2016, 2,625(12.5%) were culture-positive. A total of 413 Enterobacteriaceae available for analysis were screened for ESBL. ESBL production was detected in 160 Enterobacteriaceae, high resistance rates were observed among ESBL-positive isolates for Ceftriaxone (92.3%), Aztreonam (96.8%), Cefpodoxime (96.3%), Cefotaxime (98.8%) and Trimethoprim/sulfamethoxazole (90%), while 87.5%, 90.7%, and 91.9% of the isolates were susceptible to Imipenem, Amikacin and Meropenem respectively. Frequently detected resistance genes were blaTEM—83.8% (134/160), and, blaCTX-M 83.1% (133/160) followed by blaSHVgenes 66.3% (106/160). Co-existence of blaCTX-M, blaTEM and blaSHV was seen in 94/160 (58.8%), blaCTX-M and blaTEM in 118/160 (73.8%), blaTEM and blaSHV in 97/160 (60.6%) and blaCTX-M and blaSHV in 100/160 (62.5%) of isolates tested.

Conclusion

Our results indicate a high prevalence of bacteremia from ESBL Enterobacteriaceae in this population of children. These are resistant to commonly used antibiotics and careful choice of antibiotic treatment options is critical. Further studies to evaluate transmission dynamics of resistance genes could help in the reduction of ESBL resistance in these settings.

The effect of benzyl isothiocyanate on Candida albicans growth, cell size, morphogenesis, and ultrastructure

Candida albicans is a commensal yeast that may become pathogenic and even lethal to the host. Over the last few decades, antifungal resistance has increased, promoting screening of the antifungal potential of old and new substances. This study investigates the antifungal potential of isothiocyanates (ITCs) against C. albicans oral isolates. A preliminary susceptibility disk diffusion test (DD) was performed using allyl isothiocyanate (AITC), benzyl isothiocynanate (BITC) and phenyl ethyl isothiocyanate (PEITC) at a fixed concentration range (0.001-0.1 M). Because C. albicans isolates were more susceptible to BITC and PEITC, their effect on cell size and on germ tube formation (GTF) were tested. The most promising molecule, BITC, was further tested for effects on cell viability, oxidative stress and for ultrastructure. ITCs, especially the aromatic ones, had a significant type-, dose- and isolate-dependent anti-Candida activity. Although BITC and PEITC had similar activity against the yeast cells, BITC had a more pronounced effect on cell size and GTF. Furthermore, BITC appears to induce oxidative stress and promote changes in the cell ultrastructure, interfering with cell wall structure. Our work showed that aromatic ITCs have the potential to effect C. albicans cells in multiple ways, including size, shape and GTF (BITC and PEITC), oxidative stress, and ultrastructure (BITC). Overall, our results suggest that BITC may be effectively used against C. albicans to modulate its growth, and control or suppress its invasive potential.

Dithiin diisoimides: Synthesis and their antimicrobial studies

Sixteen derivatives of dithiin diisoimide 2a-2p have been synthesized and screened for antibacterial and antifungal activity. Compounds 2a-2g and 2i-2p are almost same or more active than gentamicine against Acinetobacter. Whereby compound 2,6-didodecyl-¹H,5H-pyrrolo[3',4',5,6][1,4]dithiino[2,3-c]pyrrole-1,3,5,7(2H,6H)-tetrone (2d) having zone of inhibition 20 mm against Acinetobacter is the most potent among all these compounds and can be used as lead compound for the treatment of Acinetobacter infection.

Antimicrobial activities of silver nanoparticles of extra virgin olive oil and sunflower oil against human pathogenic microbes

Silver nanoparticles were synthesized using extra virgin olive oil (Olea europaea L.) and sunflower oil (Helianthus annuus L.) and characterized by UV-vis spectroscopy, X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The brown color solution of olive oil nanoparticles (EVOO-NPs) and sunflower oil nanoparticles (SFO-NPs) showed typical absorption at 418 nm and 434 nm respectively. The morphology of extra virgin olive oil was found to be in semi cubic shapes with particle size of 23.45 nm (XRD) and 42.30 nm (SEM) while particle size of (SFO-NPs) had 42.30 nm (XRD) and 46.80 nm (SEM). Antimicrobial activities of crude extra virgin olive oil (EVOO), crude sunflower oil (SFO), synthesized nanoparticle from (EVOO-NPs) and (SFO-NPs) against human pathogenic strains were investigated. Synthesized nanoparticle from each oil showed a potent antimicrobial activity against all tested micro-organisms than crude oil which increased by (81.14% to 174.65 %) and by (111.65% to 192.31 %) than (EVOO) and (SFO) respectively. Both (EVOO-NPs) and (EVOO) had more antimicrobial activities than (SFO-NPs) and (SFO). EVOO (NPs) and SFO (NPs) showed maximum antibacterial activities against K. pneumoniae. Therefore (EVOO-NPs) and (SFO-NPs) could be used as safe natural product against multidrug resistant microbes.

Antimicrobial and synergistic activity of thiazoline derivatives in combination with conventional antibiotics against multidrug resistant Staphylococcus aureus isolated from abscess drainage samples

Emergence and spread of multidrug resistant (MDR) Staphylococcus aureus strains is becoming major challenge in treatment of soft tissue infections. This study aimed to explore antimicrobial and synergistic antimicrobial potential of three commercially available thiazoline derivatives (2-amino-2-thiazoline, 2-thiazoline-2-thiol and 2-acetyl-2-thiazoline) against MDR Staphylococcus aureus strains isolated from abscess drainage samples (n=20). MDR Staphylococcus aureus isolates were identified by Kirby-Bauer disk diffusion assay and were further subjected to molecular identification by 16srRNA amplification and DNA sequencing. Minimum Inhibitory Concentration (MIC) values of test compounds and antibiotics (0.25-512μg/mL) were measured and subsequently, synergism assay was performed to calculate Fractional Inhibitory Concentration (FIC) index. Out of twenty Staphylococcus aureus isolates, sixteen (80%) were found to be MDR whereas four (20%) were Non-MDR. Moxifloxacin and vancomycine were found most effective antibiotics, inhibiting 100% (n=20) and 95% (n=19) strains respectively. Antimicrobial activity of 2-amino-2-thiazoline (MIC: 32μg/mL), 2-thiazoline-2-thiol (MIC: 64μg/mL) and 2-acetyl-2-thiazoline (MIC: 32μg/mL) was found significant against all ten tested MDR strains. Synergistic combinations of thiazoline derivatives with test antibiotics reduced MIC values significantly. Therefore, combination of tested thiazoline derivatives with antibiotics could be used as alternative therapeutic approach to treat soft tissue infections caused by MDR Staphylococcus aureus after further pre-clinical and clinical studies.

Comparative study of antibacterial activity between Schiff base nicotinic hydrazide derivative and its silver architected nanoparticles with atomic force microscopic study of bacterial cell wall

The threat of multi-drug resistant bacterial pathogens evokes researchers to synthesized safe and effective chemotherapeutic agents for nano-drug delivery system. In current study, Schiff base of nicotinic hydrazide(NHD) and its silver nanoparticles(NHD-AgNPs) were synthesized and characterized. These compounds were investigated for cytotoxicity, antibacterial and AFM activity. The NHD showed LD50 at >1000μg/mL while NHD-AgNPs didn't exhibit toxicity at 1000μg/mL against 3T3 cell line. The NHD showed zone of inhibition against two strains of salmonella enteric (ATCC 14028 and 700408) 45.29±1.66 and 48.01±1.43mm respectively at 160μg/mL (p<0.01) while NHD-AgNPs exhibited 55.87±2.08 and 52.88±1.42 mm respectively at 130μg/mL (p<0.001) in disc diffusion method. NHD showed more than 70% growth inhibition for both strains at 85 and 125μg/ml (p<0.01) respectively, while NHD-AgNPs inhibit 80% and 75% respectively at 75 and 125 μg/ml (p<0.01, p<0.001) against Alamar blue antibacterial assay. For morphological changes in bacterial cell wall NHD and NHD-AgNPs treated bacterial cells were observed under atomic force microscope(AFM) and treated bacterial cells were severely damaged with leaked cytoplasmic contents as compare to untreated bacterial cell. These results validate that NHD-AgNPs were highly active as compared to NHD against both strains at their MIC concentrations. In future, comparative wound healing potential will be emphasized.

Antibacterial activity of eco-friendly zinc nanoparticles prepared from leaf extract of Mentha piperita L

The study aims to prepare reliable, ecofriendly and cost efficient zinc nanoparticles (Zn NPs) by Mentha piperita L. leaf extract and zinc sulfate heptahydrate, for four pathogenic bacteria. Synthesized NPs were investigated by using X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Zeta Potential. Disc diffusion method was used to check their antibacterial activity. For synthesizing Zn NPs leaf extract was used as a biological reducing agent. During reaction, appearance of cloudy white solution due to reduction in the number of zinc ions, indicated the Zn NPs formation. XRD determined the average NPs size i.e. 9.8 nm. FTIR confirmed the presence of functional groups in the leaf extract sample. Spherical shape of the NPs was confirmed by the SEM analysis. Antibacterial activity of the Zn NPs was measured by the inhibition zones against various bacteria (E. coli, P. aeruginosa, S. aureus and S. pneumoniae). Inhibition zones were observed in the range of 2.9 to 12.9 mm.

Propranolol, chlorpromazine and diclofenac restore susceptibility of extensively drug-resistant (XDR)-Acinetobacter baumannii to fluoroquinolones

Nosocomial infections caused by extensively drug-resistant (XDR) or Pan-Drug resistant (PDR) Acinetobacter (A.) baumannii have recently increased dramatically creating a medical challenge as therapeutic options became very limited. The aim of our study was to investigate the antibiotic-resistance profiles and evaluate the various combinations of ciprofloxacin (CIP) or levofloxacin (LEV) with antimicrobial agents and non-antimicrobial agents to combat antimicrobial resistance of XDR A. baumannii. A total of 100 (6.25%) A. baumannii clinical isolates were recovered from 1600 clinical specimens collected from hospitalized patients of two major university hospitals in Upper Egypt. Antimicrobial susceptibility tests were carried out according to CLSI guidelines. Antimicrobial susceptibility testing of the respective isolates showed a high percentage of bacterial resistance to 19 antimicrobial agents ranging from 76 to99%. However, a lower percentage of resistance was observed for only colistin (5%) and doxycycline (57%). The isolates were categorized as PDR (2; 2%), XDR (68; 68%), and multi-drug resistant (MDR) (30; 30%). Genotypic analysis using ERIC-PCR on 2 PDR and 32 selected XDR isolates showed that they were not clonal. Combinations of CIP or LEV with antibiotics (including, ampicillin, ceftriaxone, amikacin, or doxycycline) were tested on these A. baumannii non-clonal isolates using standard protocols where fractional inhibitory concentrations (-FICs) were calculated. Results of the respective combinations showed synergism in 23.5%, 17.65%, 32.35%, 17.65% and 26.47%, 8.28%, 14.71%, 26.47%, of the tested isolates, respectively. CIP or LEV combinations with either chlorpromazine (CPZ) 200 μg/ml, propranolol (PR) in two concentrations, 0.5 mg/ml and 1.0 mg/ml or diclofenac (DIC) 4 mg/ml were carried out and the MIC decrease factor (MDF) of each isolate was calculated and results showed synergism in 44%, 50%, 100%, 100% and 94%, 85%, 100%, 100%, of the tested isolates, respectively. In conclusion, combinations of CIP or LEV with CPZ, PR, or DIC showed synergism in most of the selected PDR and XDR A. baumannii clinical isolates. However, these combinations have to be re-evaluated in vivo using appropriate animal models infected by XDR- or PDR- A. baumannii.

Antibacterial activity and mode of action of potassium tetraborate tetrahydrate against soft-rot bacterial plant pathogens

Bacterial soft rot caused by the bacteria Dickeya and Pectobacterium is a destructive disease of vegetables, as well as ornamental plants. Several management options exist to help control these pathogens. Because of the limited success of these approaches, there is a need for the development of alternative methods to reduce losses. In this study, we evaluated the effect of potassium tetraborate tetrahydrate (PTB) on the growth of six Dickeya and Pectobacterium spp. Disc diffusion assays showed that Dickeya spp. and Pectobacterium spp. differ in their sensitivity to PTB. Spontaneous PTB-resistant mutants of Pectobacterium were identified and further investigation of the mechanism of PTB resistance was conducted by full genome sequencing. Point mutations in genes cpdB and supK were found in a single Pectobacterium atrosepticum PTB-resistant mutant. Additionally, point mutations in genes prfB (synonym supK) and prmC were found in two independent Pectobacterium brasiliense PTB-resistant mutants. prfB and prmC encode peptide chain release factor 2 and its methyltransferase, respectively. We propose the disruption of translation activity due to PTB leads to Pectobacterium growth inhibition. The P. atrosepticum PTB-resistant mutant showed altered swimming motility. Disease severity was reduced for P. atrosepticum-inoculated potato stems sprayed with PTB. We discuss the potential risk of selecting for bacterial resistance to this chemical.

Assessment of antibacterial activity of levonadifloxacin against contemporary gram-positive clinical isolates collected from various Indian hospitals using disk-diffusion assay

Objectives

Levonadifloxacin is a novel benzoquinolizine subclass of quinolone with broad-spectrum activities against problematic pathogens such as methicillin-resistant Staphylococcus aureus, quinolone-resistant S. aureus, vancomycin intermediate S. aureus, and vancomycin-resistant S. aureus. Levonadifloxacin and its oral prodrug, alalevonadifloxacin, have been recently approved in India for the treatment of acute bacterial skin and skin structure infections, including concurrent bacteraemia and diabetic foot infections. The aim of the study is to assess the activity of levonadifloxacin against Gram-positive clinical isolates collected from various Indian hospitals using the disc-diffusion method.

Materials and Methods

Nonduplicate isolates of S. aureus and other Gram-positive isolates collected from June 2019 to March 2020 were subjected to levonadifloxacin susceptibility testing (disk diffusion method) as per the Clinical and Laboratory Standards Institute guidelines (Year 2019). Levonadifloxacin 10 μg impregnated disks were used during the testing.

Results

A total of 664 diverse Gram-positive clinical isolates collected from six different hospitals in India were analyzed. Majority (65.5%) of the isolates were S. aureus. All the S. aureus and other Gram-positive isolates were found to be susceptible to levonadifloxacin as per the prespecified interpretive criteria identified based on population pharmacokinetic model and Monte Carlo simulation enabled probability of pharmacodynamic target attainment analysis.

Conclusions

The present study showed that levonadifloxacin was highly active against contemporary Gram-positive pathogens and furthermore demonstrated that levonadifloxacin susceptibilities can be reliably determined using the disc-diffusion method.

Multi-drug resistant and extended-spectrum β-lactamases producing bacterial uropathogens among pregnant women in Northwest Ethiopia

INTRODUCTION

Above 80% of urinary tract infections are caused by enteric bacteria, which are known for years by their drug-resistant ability. Though the prevalence of drug-resistant strains is increasing in the world, it is not well known in low-income countries. The aim of this study was to assess the prevalence of Multi-drug resistance, Extended-spectrum β-lactamases production, and associated risk factors among pregnant women in Northwest Ethiopia.

METHODS

A hospital-based cross-sectional study was conducted among pregnant women from March to May 2017. A total of 384 clean-catch midstream urine sample was collected from study participants. Bacterial identification and drug susceptibility testing were done following standard microbiological techniques; Extended-spectrum β-lactamase production was screened using a disc diffusion test and confirmed by a combination disc test. The data were entered and analyzed by using SPSS version 20, and a p-value of less than 0.05 was considered as statistically significant.

RESULT

The overall prevalence of urinary tract infection was 15.9% (95% CI 12.8-20.1%). E. coli (49.2%), CoNS (27.9%), and S. aureus (18%) were the main uropathogens. The prevalence of MDR uropathogens was 60.65%. The prevalence of ESBLs production among cases caused by Enterobacteriaceae was 18.2%. The drug resistance rate of Gram-negative isolates was higher for ampicillin (90.9%), cephalothin (84.8%), and augmentin (57.6%). The drug nitrofurantoin showed the highest activity (100%) against Gram-negative isolates. Gram-positive isolates were showed low susceptibility to penicillin (89.3%) and cotrimoxazole (75%); however highest susceptibility rate for gentamicin (100%), amikacin (100%), and nitrofurantoin (98.36%) was recorded. Prior antibiotic therapy (AOR = 5.46, 95% CI 1.38-21.65) was a risk factor for the presence of multi-drug resistant bacteria.

CONCLUSION AND RECOMMENDATION

The multi-drug resistance prevalence was high among uropathogen, thus treatment of urinary tract infection during pregnancy; should be based on the antibacterial susceptibility testing result. The isolation of drug-resistant strains like Extended-spectrum β-lactamases in this study calls for the need of periodic and continuous follow-up of antibiotic usage among pregnant women. Nitrofurantoin, gentamicin, amikacin, and ciprofloxacin/norfloxacin showed higher activity against bacterial uropathogen.

Antidiarrheal potential of lactobacillus strains isolated from pharmaceutical formulations for the treatment of pediatric diarrhea

The consumption of probiotics in the prevention and treatment of diarrhea have been clinically justified, comprehensive studied and explored in many products around the world. In Pakistan, recommendation of probiotic formulations is being emerged to control the increased mortality and morbidity from diarrhea under 5 years of age children. The objective of the study was to evaluate the antimicrobial potential of isolated Lactobacillus strains against diarrheagenic Escherichia coli. Twelve strains were isolated from different probiotic pharmaceutical formulations available in Pakistan. Physiological and biochemical characteristics of isolates were analyzed. Selective media was used for the growth of probiotic isolates and E. coli. Agar spot and well diffusion methods were employed to evaluate the antimicrobial activity of isolates and measured as a zone of inhibition (mm). Changes in cell morphology was observed by Scanning Electron Microscopy. Statistical analysis was adopted with a level of significance p<0.05. L. reuteri (28 mm) and L.plantarum (26 mm) showed significant inhibitory actions against E. coli due to increased organic acids and bacteriocins formations. Rest of isolates exhibited mild to moderate activity with an average inhibition (20 mm). L. sporogenes demonstrated weak antagonistic behavior. Use of multiple strains of Lactobacillus along with L. reuteri or L.plantarum as a therapeutic agent or in nutritional supplements could be a novel approach for the prevention and treatment of pediatric diarrhea.

Comparison of methods for the detection of in vitro synergy in multidrug-resistant gram-negative bacteria

BACKGROUND

The use of combined antibiotic therapy has become an option for infections caused by multidrug-resistant (MDR) bacteria. The time-kill (TK) assay is considered the gold standard method for the evaluation of in vitro synergy, but it is a time-consuming and expensive method. The purpose of this study was to evaluate two methods for testing in vitro antimicrobial combinations: the disk diffusion method through disk approximation (DA) and the agar gradient diffusion method via the MIC:MIC ratio. The TK assay was included as the gold standard. MDR Gram-negative clinical isolates (n = 62; 28 Pseudomonas aeruginosa, 20 Acinetobacter baumannii, and 14 Serratia marcescens) were submitted to TK, DA, and MIC:MIC ratio synergy methods.

RESULTS

Overall, the agreement between the DA and TK assays ranged from 20 to 93%. The isolates of A. baumannii showed variable results of synergism according to TK, and the calculated agreement was statistically significant in this species against fosfomycin with meropenem including colistin-resistant isolates. The MIC:MIC ratiometric agreed from 35 to 71% with TK assays. The kappa test showed good agreement for the combination of colistin with amikacin (K = 0.58; P = 0.04) among the colistin-resistant A. baumannii isolates.

CONCLUSIONS

The DA and MIC:MIC ratiometric methods are easier to perform and might be a more viable tool for clinical microbiology laboratories.

Prevalence of oxacillin-susceptible methicillin-resistant Staphylococcus aureus nasal carriage and their clonal diversity among patients attending public health-care facilities

Context

Nosocomial infections arise from many microorganisms, including Staphylococcus aureus.

Aims

The aim of this study is to determine the molecular epidemiology of circulating methicillin-resistant S. aureus (MRSA) clones among patients attending community and health-care facilities in Nova Friburgo, RJ, Brazil.

Methods

A total of 1002 nasal swab samples were collected from May 2010 to September 2015. S. aureus isolates were identified through phenotypic tests, submitted to antimicrobial susceptibility tests and genotypic analysis to detect mecA, panton-valentine leucocidin (PVL) genes, SCCmec, SPA and multilocus sequencing typing (MLST) typing.

Results

We identified 294 (29.3%) isolates as S. aureus and 91 (9.1%) as MRSA. A total of 17 isolates did not present a correlation between phenotypic and genotypic resistance profiles. Among MRSA isolates, 17 (18.7%) carried PVL genes. A total of 20 different SPA types were determined, being grouped by MLST into eight different sequence types. ST5/t002 was the most prevalent genotype found among these isolates.

Conclusions

There is a gradual colonisation shift happening in the infection pattern by S. aureus in Brazil. The Brazilian Epidemic Clone (ST239-SCCmec IIIa-PVL-) seems to be substituted by isolates from different clonal complexes, such as ST5, ST8 and ST30. The non-correlation between phenotypic/genotypic resistance profile observed in some isolates suggests the presence of other methicillin resistance mechanisms different from mecA presence or a difference in the nucleotide sequence, which prevents the primers to identify the specific region during polymerase chain reaction reactions. MRSA identification should be based on phenotypic and genotypic testing to ensure the various types of resistance mechanisms.

Genotypic and phenotypic characterisation of clinical isolates of methicillin-resistant Staphylococcus aureus in two different geographical locations of Iran

Background

Methicillin-resistant Staphylococcus aureus (MRSA) has become more prevalent all over the world and it is important to determine MRSA prevalence and typing in different regions. The present study was carried out to determine the prevalence and frequency of circulating molecular types of MRSA isolates as well as their antibiotics susceptibility in Tabriz and Kerman cities of Iran.

Materials and Methods

A total of 230 S. aureus isolates were collected from Tabriz (n=125) and Kerman (n=105) during January to December 2018. MRSA isolates were identified by PCR amplification of nuc and mec A genes. Antibiotic susceptibility of MRSA isolates were determined by Kirby-Bauer disk diffusion method. Multiplex PCR was exploited to detect various types of SCCmec.

Results

The MRSA prevalence was 51/125 (40.8%) in Tabriz and 60/105 (57.1%) in Kerman. Overall, 36/51 (70.58%) and 15/51 (29.41%) isolates and 37/60 (61.66%) and 23/60 (38.34%) isolates were isolated from inpatients and outpatients in Tabriz and Kerman, respectively. Almost all of the isolates were resistant to penicillin and all of them were sensitive to linezolid. Thirty five (68.2%) and 34(56.6%) of MRSA isolates in Tabriz and Kerman were determined as MDR, respectively. SCCmec typing showed that the frequent SCCmec type in both Tabriz and Kerman cities was SCCmec III (56.86% and 55%, respectively).

Conclusion

The high prevalence of MRSA makes it necessary to revisit the antibiotics administration by physicians. Indeed, periodic evaluation of antibacterial susceptibility patterns of the MRSA strains is required for efficient treatment of MRSA infections.

Generation of an engineered food-grade Lactococcus lactis strain for production of an antimicrobial peptide: in vitro and in silico evaluation

BACKGROUND

Foodborne pathogens and their biofilms are considered as one of the most serious problems in human health and food industry. Moreover, safety of foods is a main global concern because of the increasing use of chemical food additives. Ensuring food safety enhances interest in discovery of new alternative compounds such as antimicrobial peptides (AMPs), which can be used as bio-preservatives in the food industry. In this study, the most important antimicrobial peptides of camel milk lactoferrin (lactoferrampin and lactoferricin) were recombinantly expressed in the form of chimeric peptide (cLFchimera) in a food-grade L. lactis strain. P170 expression system was used to express secreted cLFchimera using pAMJ1653 expression vector which harbors a safe (non-antibiotic) selectable marker.

RESULTS

Peptide purification was carried out using Ni-NTA agarose column from culture medium with concentration of 0.13 mg/mL. The results of disk diffusion test revealed that cLFchimera had considerable antimicrobial activity against a number of major foodborne bacteria. Furthermore, this chimeric peptide showed strong and weak inhibitory effect on biofilm formation against P. aeruginosa, S. aureus E. faecalis, and E. coli, respectively. Antioxidant activity and thermal stability of the chimeric peptide was determined. The results showed that cLFchimera had antioxidant activity (IC50: 310 μ/mL) and its activity was not affected after 40 min of boiling. Finally, we evaluated the interaction of the peptide with LPS and DNA in bacteria using molecular dynamic simulation as two main intra and extra cellular targets for AMPs, respectively. Our in silico analysis showed that cLFchimera had strong affinity to both of these targets by positive charged residues after 50 ns molecular dynamic simulation.

CONCLUSIONS

Overall, the engineered food-grade L. lactis generated in the present study successfully expressed a secreted chimeric peptide with antimicrobial properties and could be considered as a promising bio-preservative in the food industry.

Environmental Contamination Prevalence, Antimicrobial Resistance and Molecular Characteristics of Methicillin-Resistant Staphylococcus Aureus and Staphylococcus Epidermidis Isolated from Secondary Schools in Guangzhou, China

Background: Methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE), the most prevalent causes of hospital-associated and community-associated infections, could exist on frequently touched surfaces. This study aims to determine the contamination prevalence and the characteristics of MRSA and MRSE isolated from secondary school environments. Methods: We collected environmental samples from ten secondary schools in Guangzhou city between October 2016 and January 2017. The samples were confirmed for MRSA and MRSE isolates by using biochemical tests and polymerase chain reactions. Antimicrobial susceptibility testing was performed by the Kirby-Bauer disk diffusion method. Staphylococcal cassette chromosome mec (SCCmec) typing, toxin gene screening, and multilocus sequence typing (MLST) were performed to further characterize the isolates. Data were analyzed by two-sample proportion tests. Results: A total of 1830 environmental samples were collected. The prevalence of MRSA and MRSE contamination were 1.86% (34/1830) and 5.14% (94/1830), respectively. The proportions of multidrug resistance in both MRSA (58.82%) and MRSE (63.83%) isolates were high. Seven clonal complexes (CC) and 12 sequence types (ST) were identified, with the CC5 (35.29%) and ST45 (25.53%) being the most prevalent. We found that 44.12% of the MRSA isolates were community-acquired and the main type was ST45-SCCmec IV. We found that 5.88% and 32.35% of MRSA isolates were positive to Panton-Valentine leukocidin (PVL) and toxic shock syndrome toxin-1 (tst) gene, respectively. No MRSE isolate was positive to the toxin genes. Conclusion: Our findings raise potential public health concerns for environmental contamination of MRSA and MRSE in school environments. Surfaces of school environments may potentially provide a source for cross-contamination with these bacteria into the wider community.

High clonal diversity of ESBL-producing Klebsiella pneumoniae isolates from clinical samples in a non-outbreak situation. A cohort study

Background

Klebsiella pneumoniae has been responsible for a large number of clonal hospital outbreaks. However, some epidemiological changes have been observed since the emergence of CTX-M enzymes in K. pneumoniae.

Aim

To analyse the transmission dynamics of Extended Spectrum β-Lactamase-producing Klebsiella pneumoniae (ESBL-Kp) in an acute care hospital.

Methods

In 2015 a prospective cohort study was conducted. All new consecutive adult patients with ESBL-Kp isolates in all clinical samples were included. Patients with a previous known infection/colonization by ESBL-Kp and patients in high risk areas (e.g., intensive care units) were excluded. Cross-transmission was defined as the carriage of a clonally-related ESBL-Kp between newly diagnosed patients who shared the same ward for ≥48 h with another case, within a maximum time window of 4 weeks. ESBL-production was confirmed using the double-disk diffusion method and PCR. Clonal relationships were investigated by rep-PCR and multilocus sequence typing (MLST).

Results

Sixty ESBL-Kp isolates from 60 patients were included and analysed. Infections and colonizations were classified as hospital-acquired (52%), healthcare-related (40%) or community-acquired (8%).High genetic diversity was detected. When epidemiological clinical data were combined with the rep-PCR, the patterns identified did not show any cases of cross-transmission. ESBL-Kp were detected in 12.5% of environmental samples. No clonal relationship could be established between environmental reservoirs and patients. The genetic mechanism detected in all strains was associated with blaCTX-M genes, and 97% were CTX-M-15.

Conclusions

The dynamics of ESBL-K. pneumoniae isolated in our setting could not be explained by clonal transmission from an index patient. A polyclonal spread of ESBL-Kp was identified.

<i>In vitro</i> and <i>in vivo</i> Antibacterial effect of <i>Commiphora gileadensis</i> Methanolic Extract against Methicillin-Resistant <i>Staphylococcus aureus</i> (MRSA) and <i>Pseudomonas aeruginosa</i>

BACKGROUND AND OBJECTIVE

Commiphora gileadensis is a plant in the Burseraceae family that grows in the western area of Saudi Arabia. Traditionally, it is used in the treatment of some superficial infections.

MATERIALS AND METHODS

The methanolic extract of Commiphora gileadensis isolated from its leaves and branches. The in vitro study was conducted to determine the effect of this extract on Methicillin-Resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa using an agar diffusion and Minimum inhibitory concentration (MIC) methods. The in vivo study was conducted through two different methods. The first method, 20 male Balb c-1 mice were used for the determination of Commiphora gileadensis methanolic extract toxicity (LD50). In the second method, 40 male mice were used and were put into four groups. The first and second groups were injected subcutaneously with 108 CFU of MRSA 1 mL-1, while the third and fourth groups were injected with 108 CFU of Pseudomonas aeruginosa 1 mL-1. The comparison between groups was done by using a t-test (p<0.05).

RESULTS

The methanolic extract of Commiphora gileadensis had a greater sensitivity zone on MRSA and Pseudomonas aeruginosa, 7 and 3 mm respectively. The MIC of the extract was 1/8 and 1/2 for MRSA and Pseudomonas aeruginosa respectively. The in vivo study showed that the extract was non-toxic, it also showed that the extract decreased the mortality of mice induced by MRSA injection significantly (p<0.05) While insignificantly with Pseudomonas aeruginosa.

CONCLUSION

The total Commiphora gileadensis methanolic extract had an antibacterial effect on MRSA and Pseudomonas aeruginosa. This extract was non-toxic for the mice.

Antioxidant, Antimicrobial and Wound Healing Potential of Jatropha variegata - An Interesting Plant Endemic to Yemen

BACKGROUND AND OBJECTIVE

Jatropha variegata is traditionally used in Yemeni folk medicine for antiseptic and hemostatic purposes. In this study, the methanolic extract of the plant leaves was evaluated for its antioxidant, antibacterial and wound healing activity.

MATERIALS AND METHODS

The antioxidant activity was assessed using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay. The antibacterial activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa was tested using disc diffusion and broth microdilution assays. In vivo, the ability of the extract to accelerate wound healing in rats was evaluated using both wound area measurements and histological analyses.

RESULTS

The leaves extract exhibited strong antioxidant activity with an IC50 value of 16.7 μg mL-1. The extract exhibited moderate antibacterial activity against S. aureus with inhibition zones of 10.6 mm, and the Minimum Inhibitory Concentration (MIC) value was 5 mg mL-1. The extract significantly accelerated the rate of wound healing closure compared to those treated with the vehicle. In addition, histopathological analyses of wound granulation tissues showed significantly better healing signs after 14 days in the extract-treated groups, with denser collagen deposition at the injury site.

CONCLUSION

The leaves of J. variegata appear to contain bioactive compounds that may be utilized clinically in combating oxidative stress and in wound management.

In vitro and in vivo fitness of clinical isolates of carbapenem-resistant and -susceptible Acinetobacter baumannii

Context

Acinetobacter baumannii is one among the leading nosocomial pathogens in the healthcare settings worldwide. Limited data on relative fitness and virulence of carbapenem-resistant A. baumannii (CRAB) are known. New methods are required to curb the rapidly rising antimicrobial resistance of this bug.

Aims

We aimed to study the comparative in vitro and in vivo fitness of clinical isolates of CRAB and carbapenem-susceptible A. baumannii (CSAB).

Settings and Design

A total of nine A. baumannii isolates were included in this study. CSAB ATCC-19606 was taken as a reference control strain.

Subjects and Methods

Matrix-assisted laser desorption ionisation-time of flight mass spectrometry and gyrB and blaOXA-51PCR were used for species identification. Antimicrobial susceptibility was performed using Kirby-Bauer disk-diffusion method. Minimum inhibitory concentration for carbapenems (imipenem, meropenem and doripenem) was determined using agar dilution method. End point analysis, competitive index (CI), growth kinetics and generation time were determined for CRAB and CSAB isolates. In vivo fitness of CRAB and CSAB was determined using Caenorhabditis elegans host model. Multilocus sequence typing was performed to see the genetic relatedness of the isolates under study.

Results

End point analysis, in vitro CI and growth kinetics experiments showed better fitness of clinical isolates of CRAB over CSAB ones. In vivo'nematode fertility assay' using C. elegans also supported the in vitro results.

Conclusions

To the best of our knowledge, this is the first study of its kind from India showing difference in fitness of clinical isolates of CRAB and CSAB.