Search

Disc and well diffusion methods were used to test the antibacterial activity of methanol extract and ethanol extract of the selected ethnomedicinal plant viz. Garcinia pedunculata Roxb. ex Buch.-Ham. Both the methanol extract and ethanol extract were subjected to antibacterial activity assay against the six clinical isolates. Antibiotic sensitivity test of the test bacteria against standard antibiotics were also determined. All the bacterial pathogens (Staphylococcus aureus, Enterococcus faecalis, Enterobacter cloacae, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae) were exposed to the plant extract in triplicates. The investigation revealed the potency of G. pedunculata extract as an effective antibacterial agent against both Gram-positive bacteria (GPB) and Gram-negative bacteria (GNB). G. pedunculata are evaluated to be bactericidal against the tested bacteria. The antibacterial activity may be due to an individual compound or synergistic effect of more than one compound present in the medicinal plant extract. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of the plant extracts were also investigated by using the broth microdilution method. HPLC-MS of the methanol extract of G. pedunculata fruit revealed the presence of Hydroxy Citric Acid Lactone (MW-190), Garcinone-E (MW-464), a-Mangostin (MW-410), β–Mangostin (MW-424), and γ-Mangostin (MW-396).

Abstract Objective Although many bacterial culture media are available commercially, there is a continuous effort to develop better selective media for bacteria, which cannot be grown on existing media. While exploring antibacterial properties of clove, we observed that it has the potential to selectively inhibit growth of certain types of bacteria. This led us to do the experiments, which resulted in developing a new media which selectively allowed the growth of only Gram-negative bacteria, while inhibiting the Gram-positive bacteria. Results Mueller Hinton Agar (MHA) was used as the base media and was modified to develop MHA-C15 (MHA containing 15% volume/volume water extract of clove). Gram-negative bacterial pathogens Escherichia coli, Klebsiella pneumoniae, Salmonella typhimurium and Pseudomonas aeruginosa grew on MHA-C15. However, none of the major Gram-positive bacterial pathogens such as Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus mutans, Bacillus spp. and Enterococcus spp. grew on it. Taken together, these findings show that MHA-C15 is a newly developed selective media for culture of Gram-negative bacteria.

Introduction: Methicillin-Resistant Staphylococcus aureus (MRSA) has spread throughout the world as a hospital and communityacquired illness. Although, a variety of strategies have been employed, laboratory identification of MRSA remains a difficulty. Aim: To examine several phenotypic approaches for accuracy results, with an (Epsilometer) E-test based method serving as the gold standard for MRSA identification. Materials and Methods: A prospective observational study was conducted in the Microbiology Department of Santosh Medical College, Ghaziabad, Uttar Pradesh, India, from August 2020 to July 2021. Total of 384 isolates S. aureus were identified by using the required samples including pus, swab, blood, wound and urine, etc., which were collected from the Microbiology department and the comparison was done between E-test serving as the gold standard for MRSA identification with Cefoxitin Disk Diffusion (CDD)/Oxacillin Disk Diffusion method (ODD). The diagnostic kit for using E-test in collected samples was purchased from Himedia Laboratries Pvt., Ltd., Mumbai, India (EM0065). The data was calculated by using MS-Excel. Results: A total of 113 strains were revealed to be MRSA in clinical specimens out of 384 isolated S. aureus according to Cefoxitin (disc diffusion method). The gold standard method was chosen to be the E-test, which had found a high sensitivity of 79.8% and a specificity of 94.2% compared to the cefoxitin/ ODD method. Isolates including MRSA were highly susceptible to teicoplanin and linezolid. Conclusion: The present study concludes that E-test (strip) method is a high sensitivity and highly specific for detecting MRSA in comparison to other disk methods used in this study. Due to less number of sample size and lesser time period more studies are needed to establish this fact.

Indonesia merupakan salah satu negara berkembang yang menghadapi penyakit infeksi. Staphylococcus aureus merupakan patogen utama pada manusia dan hampir setiap orang pernah mengalami infeksi Staphylococcus aureus yang bervariasi dalam beratnya, mulai dari keracunan makanan hingga infeksi kulit ringan sampai berat yang mengancam jiwa. Namun mengingat tingginya angka resistensi antibiotik maka penggunaan tanaman obat sebagai alternatif terapi merupakan pilihan yang lebih aman. Penelitian Ini Bertujuan Mengetahui khasiat ekstrak jintan hitam dalam menghambat pertumbuhan bakteri Staphylococcus aureus. Penelitian ini adalah penelitian experimental post test dengan menggunakan metode disc diffusion untuk melihat bagaimana efektivitas Ekstrak Jintan Hitam (Nigella sativa) sebagai antimikroba terhadap Staphylococcus aureus secara in vitro. Pada ekstrak jintan hitam didapatkan zona hambat yang paling tinggi pada konsentrasi 100% dengan rerata zona hambat sebesar 24 mm, sedangkan zona hambat yang paling rendah yaitu pada konsentrasi 25% dengan rerata zona hambat sebesar 10 mm.Pada kontrol positif menggunakan antibiotik Kloramfenikol didapatkan rerata zona hambat sebesar 30 mm yakni sensitif menghambat pertumbuhan bakteri, sedangkan pada kontrol negatif menggunakan akuades tidak terbentuk zona hambat. Terbentuk daya hambat terhadap bakteri Staphylococcus aureus dengan pemberian ekstrak jintan hitam pada semua konsentrasi.

At present, a rise of antimicrobial resistance requires that susceptibility of infectious agents to antimicrobial agents could be accurately evaluated as related errors may lead to selecting improper therapeutics provoking spread of drug resistance. Pathogen sensitivity to antimicrobial agents is commonly determined by a disc diffusion method. A quality of nutrient medium used in assays plays a crucial role influencing final results. In Russia, it turned out that regulatory documents such as the nationwide guidelines and clinical recommendations outlining methodology for antimicrobial susceptibility testing underlay availability in domestic market few nutrient media, including Mueller–Hinton Agar, AGV medium etc. exhibiting sometimes unsatisfactory quality. To harmonize such methodology with international requirements, theStateResearchCenterfor Applied Microbiology and Biotechnology has developed a technology and promoted manufacture of Russia-made Mueller–Hinton agar satisfying requirements of EUCAST documents, clinical guidelines, and ISO/TS 16782:2016. The main objective of this study was to compare quality of new agar product with five similar foreign media while examining 11 test strains by disc diffusion method. As a result, some of nutrient media available to the Russian market turned out to be off-standard: not all of them satisfy to the EUCAST requirements and clinical guidelines since diameter distribution for growth inhibition recommended by EUCAST for quality control does not fit into permissible range. Moreover, susceptibility of P. aeruginosa ATCC 27853 to aminoglycosides, fluoroquinolones, Meropenem, as well as S. aureus ATSS 25923 and E. faecalis ATCC 29212 to tigecycline was assessed with certain mistakes. The data obtained by us were analyzed in accordance to the new document ISO/TS 16782:2016 “Clinical laboratory testing — criterion for acceptable lots of dehydrated Mueller–Hinton agar and broth for antimicrobial susceptibility testing”, not approved yet In Russia. To determine potential reason for deviation of data from reference range, we measured concentration of bivalent metals in all nutrient media examined by atomic emission spectrometry with inductively coupled plasma. We determined new patterns affecting reliability of results on microbial antibiotic susceptibility. A need to check intralaboratory quality control of nutrient media was emphasized.

Objective: Although many bacterial culture media are available commercially, there is a continuous effort to develop better selective media for bacteria, which cannot be grown on existing media. While exploring antibacterial properties of clove, we observed that it has the potential to selectively inhibit growth of certain types of bacteria. This led us to do the experiments, which resulted in developing a new media which selectively allowed the growth of only Gram-negative bacteria, while inhibiting the Gram-positive bacteria. Results: Mueller Hinton Agar (MHA) was used as the base media and was modified to develop MHA-C15 (MHA containing 15% volume/volume water extract of clove). Gram-negative bacterial pathogens Escherichia coli, Klebsiella pneumoniae, Salmonella typhimurium and Pseudomonas aeruginosa grew on MHA-C15. However, none of the major Gram-positive bacterial pathogens such as Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus mutans, Bacillus spp. and Enterococcus spp. grew on it. Taken together, these findings show that MHA-C15 is a newly developed selective media for culture of Gram-negative bacteria. [ABSTRACT FROM AUTHOR]

Introduction: Methicillin-Resistant Staphylococcus aureus (MRSA) has spread throughout the world as a hospital and communityacquired illness. Although a variety of strategies have been employed, laboratory identification of MRSA remains a difficulty. Aim: To examine several phenotypic approaches for accuracy results, with an (Epsilometer) E-test based method serving as the gold standard for MRSA identification. Materials and Methods: A prospective observational study was conducted in the Microbiology department of Santosh Medical College, Ghaziabad, Uttar Pradesh, India, from August 2020 to July 2021. Total of 384 isolates S.aureus were identified by using the required samples including pus, swab, blood, wound and urine, etc., which were collected from the Microbiology department and the comparison was done between E-test serving as the gold standard for MRSA identification with Cefoxitin Disk Diffusion (CDD)/Oxacillin Disk Diffusion method (ODD). The diagnostic kit for using E-Test in collected samples was purchased from Himedia Laboratries Pvt., Ltd., Mumbai, India (EM0065). The data was calculated by using MS-Excel. Results: A total of 113 strains were revealed to be MRSA in clinical specimens out of 384 isolated S.aureus. The gold standard method was chosen to be the E-Test, which had found a high sensitivity of 79.8% and a specificity of 94.2%. Compared to the cefoxitin/oxacillin disc diffusion method, isolates including MRSA were highly susceptible to Tiecoplanin and Linezolid. Conclusion: The present study concludes that E-Test (strip) method is a high sensitivity and highly specific for detecting MRSA in comparison to other disk methods used in this study. Due to less number of sample size and lesser time period more studies are needed to establish this fact. [ABSTRACT FROM AUTHOR]

Background and Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is an important human pathogen and normally colonize in body parts including skin, nose, inguinal folds, perineum and throat and accounts for nearly two-third of all S.aureus infections in hospitals. MRSA is resistant not only to all ß-lactam group but also other antibiotics including aminoglycosides, tetracycline and macrolides. The study was undertaken for the rapid detection of MRSA utilizing CHROMagar MRSA (CMRSA). Methods: Two hundred nasal samples were taken with sterile wooden swab, inoculated on CMRSA and Mueller Hinton agar (MHA) with cefoxitin disc (30µg). All the studied samples were taken from 3 days old hospitalized patients. Results: At 37°C of incubation after 24h, 10.5% of the total studied samples were positive for MRSA while another 12% samples showed positive results with an extended period of incubation upto 48 h on CMRSA plates. Thus a total of 22.5% were positive for MRSA. 6.5% of the total samples showed methicillin resistance confirmed with novobicin disc (30ƒÊg) and were identified as Staphyloccocus epidermidis (MRSE) on MHA with cefoxitin disc after 24h of incubation. Conclusion: It is concluded that CMRSA is equal in activity as compared to Mueller Hinton agar with cefoxitin disc which requires at least 3 days of sample processing, so CMRSA can be used for the rapid detection of MRSA without utilization of additional sources. [ABSTRACT FROM AUTHOR]

Infections occurring more than 48 hours after admission in hospital are usually considered as nosocomial infections. Patients in ICUs are at a higher risk of acquiring this infection than those in non-critical areas. The total length of stay increased from three days to nineteen days for clinical procedures. Increased antimicrobial resistance in such cases makes increase in mortality and morbidity. The ICU infection rates is five to ten times higher than HAIs in ward patients. ICU acquired infections are major health problem globally, in developing countries like Pakistan. The microorganisms that are frequently isolated from intensive care units are Acinetobacter spp, P. aeruginosa, Klebsiella pneumoniae, Streptococcus spp, Staphylococcus spp, Enterococci and Enterobacteriaceae i.e E. coli, Proteus mirabilis and Serratia marcescens. Aims: The present study was aimed at to determine the frequency of causative organisms in intensive care unit (ICU) patients and antimicrobial susceptibility pattern of the isolates. Study Design: A cross-sectional study. Place and Duration of Study: Microbiology section of Pathology department Sheikh Zayed Medical College/Hospital, Rahim Yar Khan. Four months (September to December 2015). Materials and Methods: Clinical samples from patients having signs and syptoms of site-specific infections or fever in ICU were collected. The samples were cultured on suitable culture media and bacterial isolates were identified by Gram stain and standard biochemical methods. Antimicrobial susceptibility testing to conventional and newer antibiotics was performed on Mueller Hinton agar using disc diffusion method. Frequency percentages of all isolates were determined. Results: Out of 100 samples only 30 samples were positive for growth and 70 samples showed no growth. The most frequent isolates were E. coli (40%), K. pneumoniae (10%) P. aeruginosa (10%) Proteus spp. (20%) Acinetobacter (17%) and S.aureus (3%). S.aureus (Gram positive bacteria) were more sensitive to imipenem, cefoxitin and resistant to ceftriaxone, nitrofurantoin azithromycin, Tetracycline, Cefotaxime and amoxicillin clavulanic acid. Other Gram negative bacteria i.e E.coli, K. Pneumoniae, P.aeruginosa, Proteus spp. and Acinetobacter spp. were sensitive to imipenem, sulzone, ceftriaxone, Ciprofloxacin, Gentamicin, Nitrofurantoin and resistant to amoxicillin clavulanic acid. Conclusion: Bacteria were isolated from 30% clinical samples taken from patients admitted in ICU. The most frequent site of infection was the respiratory tract followed by urinary tract and blood stream infections. E. coli, P. aeruginosa, K. pneumonia, Proteus spp., Acinetibacter and S. aureus were isolated. The high frequency of Health associated infections and elevated bacterial resistance rate in ICU patients suggest that more strict measures regarding infection control practices can be done. [ABSTRACT FROM AUTHOR]

One of the more difficult problems in the standardization and improvement of the performance of the culture media is the optimization of the Mueller Hinton Agar (MHA). The actual requisites vary from one microorganism to another, due to their different resistance to antimicrobial substances, their genetic variability and the differences in nutrient's requirements. The aim of this work was the optimization of the BioCen Mueler Hinton Agar formulation in order to standardize the diameter of the inhibition halo according to the CLSI. Different nutritive bases and their concentration were tested inoculating a series of ATCC bacteria strains, in the first stage, in a liquid medium comparing the absorbance of the culture at 640 nm, and in the second stage, inoculating them in the solid medium and recording the diameter and transparency of the inhibition halos against most different antibiotics. The BioCen formulation was also compared with other commercially available products from Liofilchem and Biolife (Italy), Oxoid (United Kingdom) and Quelab (Canada). The best formulation was achieved with the inclusion of 4 g/L of BioCen yeast extract, 2 g/L of OXOID meat extract and 17.5 g/L of BioCen acid casein hydrolysate. The susceptibility of all strain tested comply with the CLSI requirements and the overall performance was similar to the commercially available MHA including the response of Enterococcus faecalis to trimetoprim/sulfametoxazol. The optimized formulation of the BioCen MHA complies with the quality and functional requirements for MHA and showed consistency between industrial batches. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) of a small size were successfully synthesized using the wet chemical reduction method into the lamellar space layer of montmorillonite/chitosan (MMT/Cts) as an organomodified mineral solid support in the absence of any heat treatment. AgNO3, MMT, Cts, and NaBH4 were used as the silver precursor, the solid support, the natural polymeric stabilizer, and the chemical reduction agent, respectively. MMT was suspended in aqueous AgNO3/Cts solution. The interlamellar space limits were changed (d-spacing = 1.24-1.54 nm); therefore, AgNPs formed on the interlayer and external surface of MMT/Cts with d-average = 6.28-9.84 nm diameter. Characterizations were done using different methods, ie, ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray fluorescence spectrometry, and Fourier transform infrared spectroscopy. Silver/montmorillonite/chitosan bionanocomposite (Ag/MMT/Cts BNC) systems were examined. The antibacterial activity of AgNPs in MMT/Cts was investigated against Gram-positive bacteria, ie, Staphylococcus aureus and methicillin-resistant S. aureus and Gram-negative bacteria, ie, Escherichia coli, E. coli O157:H7, and Pseudomonas aeruginosa by the disc diffusion method using Mueller Hinton agar at different sizes of AgNPs. All of the synthesized Ag/MMT/Cts BNCs were found to have high antibacterial activity. These results show that Ag/MMT/Cts BNCs can be useful in different biological research and biomedical applications, including surgical devices and drug delivery vehicles.