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Aim The current scenario of COVID-19 pandemic has presented an almost insurmountable challenge even for the most sophisticated hospitals equipped with modern biomedical technology. There is an urgency to develop simple, fast and highly accurate methods for the rapid identification and isolation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected patients. To address the ongoing challenge, the present study offers a CLEVER assay (CRISPR-Cas integrated RT-LAMP Easy, Visual and Extraction-free RNA) which will allow RNA extraction-free method to visually diagnose COVID-19. RNA extraction is a major hurdle in preventing rapid and large-scale screening of samples particularly in low-resource regions because of the logistics and costs involved. Method and Result Herein, the visual SARS-CoV-2 detection method consists of RNA extraction-free method directly utilizing the patient's nasopharyngeal and oropharyngeal samples for reverse transcription loop-mediated isothermal amplification (RT-LAMP). Additionally, the assay also utilizes the integration of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas12-based system using different guide RNAs of N, E and an internal control POP7 (human RNase P) genes along with visual detection via lateral flow readout-based dip sticks with unaided eye (~100 min). Overall, the clinical sensitivity and specificity of the CLEVER assay were 89.6% and 100%, respectively. Conclusion Together, our CLEVER assay offers a point-of-care tool with no equipment dependency and minimum technical expertise requirement for COVID-19 diagnosis. Significance and Impact of the Study To address the challenges associated with COVID-19 diagnosis, we need a faster, direct and more versatile detection method for an efficient epidemiological management of the COVID-19 outbreak. The present study involves developing a method for detection of SARS-CoV-2 in human body without RNA isolation step that can visually be detected with unaided eye. Taken together, our assay offers to overcome one major defect of the prior art, that is, RNA extraction step, which could limit the deployment of the previous assays in a testing site having limited lab infrastructure.

Though a decline has been seen in child mortality and morbidity over the last decades, sepsis in neonates and infants remains a major cause of death. Optimal use of antibiotics in sepsis management is a key factor which can further reduce the number of poor clinical outcomes. Selecting the right antibiotic to which the offending bacteria is susceptible and administrating the antibiotic within the first hour can save many lives. However, the pharmacokinetic profile of an antibiotic is affected by developmental changes such as capacity of drug metabolizing enzymes and maturation of organ function. This can affect antibiotic exposure and response in neonates and infants. While suspecting sepsis, the primary focus of empiric treatment during the initial phase is to assure efficacy and it must be broad based to cover all suspected pathogens. Once the bacterial etiology is confirmed as a cause of sepsis and the in vitro antibiotic susceptibility is established, targeted treatment can be started which ensures optimal balance between efficacy and safety.

The emergence of SARS-CoV-2, the causative agent of coronavirus disease 2019 (COVID-19), represents a public health emergency of unprecedented proportion. The global containment efforts have been focused on testing, tracing of contacts and treatment (isolation) of those found COVID-19 positive. Since the whole genome sequences of a number of strains of this novel RNA virus were available in the public domain by early January 2020, a number of real-time polymerase chain reaction (RT-PCR) protocols were designed and used for diagnosis of this infection. Most RT-PCRs are designed for qualitative COVID-19 reporting (SARS-CoV-2 detected or not detected), but have been used for semi-quantitative estimation of viral load based on cycle threshold value. Our manuscript discusses the utility of quantitative PCR testing for COVID-19 and its patient management benefits.

Reports of clinical isolates of Cryptococcus neoformans often lack information on their mating types, molecular types, and in vitro antimycotic susceptibilities. This study compares these and other related characteristics of fifteen strains of C. neoformans obtained from cases of meningitis in different regions of India. PCR was used to determine the mating type and serotype of each strain, and Amplified Fragment Length Polymorphism was used for molecular typing of the strains. In vitro assays compared the proteinase and phospholipase activities of the strains, and the Clinical and Laboratory Standards Institute (CLSI) protocol was used to determine their minimal inhibitory concentrations (MICs) to amphotericin B (AMB), itraconazole, and fluconazole. All strains were identified as C. neoformans var. grubii (serotype A), possessed the alpha mating type, and belonged to molecular type VNII. Ten of the strains demonstrated strong proteolytic activity, and the remaining five were weakly proteolytic. Nine of the strains were positive for phospholipase. In vitro antifungal susceptibility tests, determined the MIC (µg/ml) values for AMB, itraconazole, and fluconazole to be 0.03-0.5, 0.002-03, and 2-4 µg/ml, respectively. Remarkedly, all 15 strains belonged to the relatively rare molecular type, VNII. This report is one of few studies to characterize clinical strains of C. neoformans from India.

Background: There is emergence of resistance to the last-line antibiotics such as carbapenems in Intensive Care Units (ICUs), leaving little effective therapeutic options. Since there are no more newer antibiotics in the armamentarium in the near future, it has become imperative that we harness the interdisciplinary knowledge for the best clinical outcome of the patient. Aims: The aim of the conference was to utilize the synergies between the clinical microbiologists and critical care specialists for better patient care and clinical outcome. Materials and Methods: A combined continuing medical education program (CME) under the aegis of the Indian Association of Medical Microbiologists – Delhi Chapter and the Indian Society of Critical Care Medicine, Delhi and national capital region was organized to share their expertise on the various topics covering epidemiology, diagnosis, management, and prevention of hospital-acquired infections in ICUs. Results: It was agreed that synergy between the clinical microbiologists and critical care medicine is required in understanding the scope of laboratory tests, investigative pathway testing, hospital epidemiology, and optimum use of antibiotics. A consensus on the use of rapid diagnostics such as point-of-care tests, matrix-assisted laser desorption ionization-time of flight mass spectrometry, and molecular tests for the early diagnosis of infectious disease was made. It was agreed that stewardship activities along with hospital infection control practices should be further strengthened for better utilization of the antibiotics. Through this CME, we identified the barriers and actionables for appropriate antimicrobial usage in Indian ICUs. Conclusions: A close coordination between clinical microbiology and critical care medicine opens up avenues to improve antimicrobial prescription practices.

Tuberculosis is an ancient disease which has become rampant in recent times due to it’s multidrug resistant nature. Global community is concerned about it and measures to control it are being taken in the form of Millennium Development Goals and Stop TB Strategy. These goals can be achieved by early case finding and better diagnosis. Detection of latent TB infection and it’s proper treatment is also necessary to eliminate disease. A newer vaccine which could either replace or accentuate the current BCG vaccine is also demand of the time. And the last step in the direction of elimination of TB will be judicious use of currently available drugs. It is also necessary that we come out with newer anti-TB drugs and regimens which could handle the issues like cost and toxicity. In India Revised National TB Program (RNTCP) has also implemented National Strategic Plan to eliminate TB by 2030.

A study of 125 uncomplicated urethritis in males were selected at and analysed from different angles in view the changing facets of gonococcal infection and its impact at the present time.

Causative organisms, pathogenesis and clinical features of sexually transmitted infections Principles of diagnostic evaluation and management

This study reports the anti-anaerobic properties of ranbezolid, a new investigational oxazolidinone. A time-kill kinetics study against anaerobes showed that ranbezolid was superior to linezolid and killed the anaerobic pathogens at 4-8h, except for Bacteroides fragilis where killing was observed at 24h. In addition, the time-kill kinetics study showed a concentration-dependent bactericidal potential of ranbezolid against anaerobes. Ranbezolid showed 5.39log(10) reduction and linezolid showed 1.15log(10) reduction in murine disk implant infection with B. fragilis ATCC 25285. Ranbezolid was very potent and showed fast protein synthesis inhibition against B. fragilis, a Gram-negative anaerobe. In addition, non-specific cell wall synthesis inhibition was also observed with ranbezolid. The potent and fast protein synthesis inhibition along with an additional mode of action of cell wall synthesis inhibition could be responsible for the cidal effect of ranbezolid against Gram-negative anaerobes.

Oxazolidinones are known to inhibit protein biosynthesis and act against a wide spectrum of gram-positive bacteria. A new investigational oxazolidinone, ranbezolid, inhibited bacterial protein synthesis in Staphylococcus aureus and Staphylococcus epidermidis. In S. epidermidis , ranbezolid showed inhibition of cell wall and lipid synthesis and a dose-dependent effect on membrane integrity. A kill-kinetics study showed that ranbezolid was bactericidal against S. epidermidis. In vitro translation of the luciferase gene done using bacterial and mammalian ribosomes indicated that ranbezolid specifically inhibited the bacterial ribosome. Molecular modeling studies revealed that both linezolid and ranbezolid fit in similar manners the active site of ribosomes, with total scores, i.e., theoretical binding affinities after consensus, of 5.2 and 6.9, respectively. The nitrofuran ring in ranbezolid is extended toward C2507, G2583, and U2584, and the nitro group forms a hydrogen bond from the base of G2583. The interaction of ranbezolid with the bacterial ribosomes clearly helps to elucidate its potent activity against the target pathogen.

Adhesion to biomaterial is assumed to be a crucial step in the pathogenesis of foreign body infection. Slime producing Staphylococcus epidermidis and Staphylococcus aureus have emerged as a preeminent cause of nosocomial bacteremia and infections of prosthetic medical devices. We evaluated the time-dependent anti-adhesive effect of RBx 7644 (ranbezolid), vancomycin, linezolid and quinupristin/ dalfopristin on two isolates each of S. epidermidis and S. aureus. Linezolid and quinupristin/ dalfopristin showed inhibition only at supra-inhibitory concentrations (2 and 4X MIC) following 2 and 4 h delayed treatment, whereas RBx 7644 demonstrated significant activity against adhesion of staphylococcal cells that had been treated with 2 to 6 h delay. When vancomycin treatment was delayed by 4 to 6 h, even concentrations above the MIC were unable to prevent adherence. This study indicates that RBx 7644 has anti-adhesion potential and may emerge as an important antibiotic for prevention and treatment of device-related infections caused by staphylococci.

Novel oxazolidinone derivatives of the lead compound RBx 8700, containing methylene oxygen- and methylene sulfur-linked substituents at the C5-position, were synthesized. Antibacterial screening of these compounds against a panel of resistant and susceptible Gram-positive and fastidious Gram-negative bacteria gave compounds 2 and 4 as new antibacterial agents.

Disulfiram, an alcohol antagonistic drug has been on the market since 1949 with 80% bioavailability and an established safety profile. Recently it has been reported as a P-glycoprotein efflux pump modulator. Herein we report its antifungal potential. The MIC50 and MIC90 of disulfiram for yeast isolates is 4 and 8 microg/ml, respectively, and the MIC range is 1-16 micro g/ml for both fluconazole sensitive and resistant strains. Interestingly, disulfiram also showed fungicidal activity on Aspergillus spp. with MIC50 and MIC90 of 2 and 8 microg/ml, respectively.

Vancomycin has been the drug of choice for 30 years for the treatment of methicillin-resistant Staphylococcus aureus (MRSA). Emergence of decreased vancomycin susceptibility in MRSA strains presents a significant clinical problem with few therapeutic options. This study was performed to generate and characterise S. aureus strains with reduced susceptibility to vancomycin. Eighteen S. aureus strains were subjected to serial passaging on vancomycin to generate vancomycin intermediate resistant S. aureus (VISA) strains. Minimum inhibitory concentration (MIC) determination was performed for the parent and the passaged cultures with 13 different antibiotics. The strains were tested by the following five methods: simplified population analysis; CDC method; modified vancomycin agar screen; population analysis profile (PAP); and modified population analysis (PAP-area under the curve (AUC) ratio). Phenotypic changes such as doubling time, synergy with beta-lactam antibiotics and effect on norA efflux pumps were also studied for these strains. The result indicated that 8 VISA mutants (vancomycin MICs, 8-16 microg/mL) were generated in vitro from the 18 S. aureus strains. The CDC and modified agar methods proved to be the most sensitive and specific methods for detection of VISA strains. The PAP for all the VISA strains ranged from 12 microg/mL to > 16 microg/mL, with a PAP-AUC ratio of > 1.3. All mutants showed increased doubling time compared with their parent isolate. Synergism of the vancomycin and beta-lactam combinations was observed for all methicillin-resistant mutants. Upon acquisition of vancomycin resistance, a few mutants showed decreased oxacillin resistance. Two VISA strains were chosen for molecular characterisation of the mecA gene and one mutant showed genotypic changes with deletion of mecA. Loss of norA efflux pumps leading to fluoroquinolone sensitivity was also observed in four mutants.

A novel synthesis of thiazolidine-2-thione and thiazolidin-2-one derivatives is described with the iodo-cyclothiocarbamation reaction as the key step for the heterocyclic ring formation. This new method has been applied to the synthesis of thiazolidinones as bioisosteric analogs of Linezolid 2. Antimicrobial properties of two new thiazole derivatives are reported.

Biofilm associated infections are becoming more common. Treatment outcome of device related infections cannot be predicted by the results of a standard susceptibility test such as the MIC. Microorganisms involved in device related infections have a slow growth rate and adhere to surfaces. Activity against glass adherent bacteria has been shown to be correlated with treatment outcome in animal models of catheter related infections. Drug efficacy can be predicted if glass adherent staphylococci are killed by low drug concentration. The eradication of bacteria adhering to glass beads and inhibition of biofilm formation by ranbezolid and three other antibiotics (quinupristin/dalfopristin, vancomycin and linezolid) was studied. The results indicated that ranbezolid required only (2-4 x MIC) for total clearance of glass-adherent MRSA 562 and MRSE 879, compared with vancomycin (8 x), quinupristin/dalfopristin (1-4 x) and linezolid (4-16 x MIC). In addition ranbezolid inhibited biofilm formation to a greater extent at sub MIC and MIC level. In conclusion, this study indicated that ranbezolid had potent activity against adherent staphylococci isolates and may prove useful in the prevention and treatment of device related infections caused by staphylococci.

The activity of ranbezolid (RBX 7644), a new oxazolidinone, against 306 anaerobes was compared with those of 11 other agents. The MICs at which 50% of the isolates tested are inhibited and those at which 90% of the isolates tested are inhibited (in micrograms per milliliter) were as follows: ranbezolid, 0.03 and 0.5; linezolid, 2 and 4; vancomycin, >16 and >16; teicoplanin, 1 and >16; quinupristin-dalfopristin, 1 and >8; amoxicillin-clavulanate, 0.5 and 2; imipenem, 0.125 and 1; clindamycin, 0.25 and 8; metronidazole, 1 and 4; gatifloxacin, 0.5 and 4; and moxifloxacin, 0.5 and 2, respectively. Ranbezolid had very good in vitro activity against both gram-negative and -positive anaerobes.

Objective: To describe the misidentification of Brucella melitensis as Bergeyella zoohelcum by MicroScan WalkAway®, a commonly used bacterial identification system. Clinical Presentation and Intervention: A 35-year-old man was admitted to the Intensive Care Unit with sepsis syndrome. Three sets of aerobic blood culture samples were positive after 48 h of incubation. The isolated organism was identified as B. zoohelcum using the MicroScan WalkAway (Siemens Healthcare Diagnostics Inc., West Sacramento, Calif., USA). However, due to the rareness of the pathogen, the isolate was reidentified as B. melitensis with Vitek® 2 system and later 16S ribosomal sequence analysis confirmed the isolate as B. melitensis having 100% match. Conclusion: This case showed that Brucella can be misidentified using MicroScan WalkAway. Countries where brucellosis is endemic need to be careful while using such automated identification systems in order not to miss the diagnosis of Brucella.

In most developing country settings, pregnancy and childbirth are accepted as normal events of life and it is not surprising that problems associated with pregnancy are also accepted without much ado. A new approach to measuring maternal mortality indicates that there are about 585,000 maternal deaths annually worldwide, 99 per cent of them in developing countries (AbouZhar and others, 1996). Over 20 million babies are born in India every year. The maternal mortality ratio ranges from 400 to 550 deaths per 100,000 live births, with wide variations between different states (Bhat and others, 1992). However, mortality represents just the tip of the iceberg. It has been estimated that for every maternal death, there are over 100 acute morbid episodes indicating an overall figure of 62 million morbidities annually (Koblinsky, 1993). Though these are crude estimates, they highlight the magnitude of the problem.

Decreased susceptibility of Neisseria meningitidis isolates to ciprofloxacin emerged from an outbreak in Delhi, India. Results of antimicrobial susceptibility testing of the meningococcal isolates to ciprofloxacin and further sequencing of DNA gyrase A quinolone-resistance–determining region confirmed the emergence of ciprofloxacin resistance in the outbreak.

Blue green microalgae have been identified as one of the promising groups of organism from which biochemically active natural products have been isolated. Aqueous and organic extracts of nine blue green microalgae strains were screened against in vitro generated vancomycin intermediate resistant Staphylococcus aureus (VISA) strains. Aqueous extracts of all the blue green microalgae cultures were found to be inactive, while all the organic (hexane, chloroform and methanolic) extracts of Anabaena virabilis and Anabaena sp. showed activity against VISA strains with MIC of 32–64 μg/ml.

For 260 pneumococcal and 266 staphylococcal strains, ranbezolid MICs ranged from ≤0.06 to 4 μg/ml. The MICs for pneumococci were similar irrespective of the strains' β-lactam, macrolide, or quinolone susceptibilities, and ranbezolid MICs for coagulase-negative staphylococci were lower than those for Staphylococcus aureus . Ranbezolid was bacteriostatic against pneumococci. Ranbezolid MICs were similar to or lower than those of linezolid. Vancomycin and quinupristin-dalfopristin were also very active.

Computers can help to liberate students from the burden of rote learning of facts and enhance the role of reason and imagination in the learning process. Arguably, the computers constitute the most important single resource ever to become available to the teachers and students since the invention of the printing press, and may well have a similar revolutionary effect on the way education is carried out, bringing about the massive shift from conventional expository teaching to the mediated individualized learning which is interactive, stimulating and rewarding. Soon, computers will be involved in almost all teaching. Apart from acting as data bases for information, computers will guide students through hypertext and will provide assessment at critical junctures, giving immediate feedback.

To describe the misidentification of Brucella melitensis as Bergeyella zoohelcum by MicroScan WalkAway®, a commonly used bacterial identification system.A 35-year-old man was admitted to the Intensive Care Unit with sepsis syndrome. Three sets of aerobic blood culture samples were positive after 48 h of incubation. The isolated organism was identified as B. zoohelcum using the MicroScan WalkAway (Siemens Healthcare Diagnostics Inc., West Sacramento, Calif., USA). However, due to the rareness of the pathogen, the isolate was reidentified as B. melitensis with Vitek® 2 system and later 16S ribosomal sequence analysis confirmed the isolate as B. melitensis having 100% match.This case showed that Brucella can be misidentified using MicroScan WalkAway. Countries where brucellosis is endemic need to be careful while using such automated identification systems in order not to miss the diagnosis of Brucella.

It is a prospective study based on 100 consecutive cases of diarrhea following antibiotic therapy admitted to the pediatric services of J.N. Medical College, A.M.U., Aligarh between January to December 1987. They had C. penicillin (50), chloramphenicol (34), ampicillin (34), gentamicin (34), cephalosporin (4) and cotrimoxazole (4) for 3 days to 3 weeks prior to the onset of diarrhea. Apart from routine and special investigations, naked eye and microscopic examination of stool, its culture for pathogens including Cl. difficile were carried out in all cases. Presence of Cl. difficile cytotoxin was demonstrated by observing the cytopathic. Effect on veru cell culture, 18 grew Cl. difficile (14 cyto toxin positive). Frequency of fever, vomiting, abdominal distension, dehydration and duration of diarrhea was not different (p > 0.05) in the two groups. Purge rate and presence of mucus and blood in Cl. difficile positive patients was significantly higher (p < 0.05). Eight Cl. difficile positive (7 cytotoxin+ve) were subjected to endoscopy. Three of them showed P.M. colitis and 2 non specific colitis. Chloromycetin, gentamicin and penicillin were the main culprits responsible for AAC. None of the patients given ampicillin alone suffered from AAC. The mortality was 5%.

A sandwich ELISA to detect specific protein antigens of Mycobacterium tuberculosis was developed by using polyclonal anti-BCG rabbit antibodies as the primary capture antibodies. The mycobacterial antigens were detected with horseradish peroxidase conjugated monoclonal antibodies (P 6) as secondary antibodies. The enzyme was detected by using 1,2 Phenylenediamine dihydrochloride (OPD) and Hydrogen peroxide as substrate. The antigen could be quantitated through linear regression analysis with lower detection limit of 1.25 micrograms/ml. 50 consecutive cases of infertility were examined by laparoscopy and tested for the presence of the antigen in the serum. Mycobacterial antigen could be detected in 9 of the 12 cases with definitive diagnosis of tuberculosis, 5 of the 23 where the diagnosis of tuberculosis was probable and in only 1 of 15 patients who had no laparoscopic abnormalities indicative of tuberculosis.

We screened 194 Mycobacterium tuberculosis strains isolated from tuberculosis (TB) patients in Delhi and neighboring regions in India to identify the prevalence of extensive drug resistance (XDR) in clinical isolates. Among these, 104 isolates were found to be multidrug resistant (MDR), and 6 were identified as XDR isolates, which was later confirmed by antimicrobial susceptibility testing against the respective drug screening panel. Genotyping was carried out by amplifying and sequencing the following genes: rpoB (rifampin), katG (isoniazid), gyrA (fluoroquinolones), and rrs (amikacin, kanamycin, and capreomycin). Our analyses indicated that mutations at the hot spots of these genes were positively correlated with drug resistance in clinical isolates. The key mutation observed for rpoB was in the codon for amino acid position 531 (S531L), and other mutations were seen in the hot spot, including those encoding Q510P, L511H, D516V, and H526Y mutations. We identified S315T and R463L substitutions encoded in the katG locus. An S95T substitution encoded in the gyrA locus was the most common mutation observed in fluoroquinolone-resistant isolates. In addition, we saw D94G and D94N mutations encoded in the QRDR region. The 16S rRNA ( rrs ) gene encoded mainly the A1401G mutation and an additional mutation, G1484T, resulting in ribosomal modifications. Taken together, the data in this report clearly establish the presence of phenotypically distinct XDR strains in India by molecular profiling and further identify specific mutational hot spots within key genes of XDR-TB strains.

SUMMARY: Serological evidence of infection with verotoxin-producing Escherichia coli (VTEC) was sought in 28 patients suffering from haemolytic uraemic syndrome (HUS) and 25 age- and sex-matched controls. ELISA was used to detect anti-lipopolysaccharide (LPS) antibodies to E. coli strains O157, O111, O26 and NCTC 10418, a non-VTEC strain, and Shigella dysenteriae O1. Sera from 19 of the HUS patients but from none of the 25 controls had significant antibody levels to the verotoxin-producing bacteria. Sera from 13 patients reacted with only one LPS of the four verotoxin-producing bacteria; sera from six reacted with more than one LPS antigen but not with LPS of E. coli NCTC 10418. Paired sera taken 2–3 weeks apart were obtained from 20 HUS patients; 14 of these had high levels of antibody in the acute phase sample. Analysis of antibody levels in the convalescent sera showed that one patient had an increase, one was unchanged and 12 patients had a decrease in antibody to the verotoxin-producing bacteria.

Circulating immune complexes (CIC) were estimated in 28 cases of Non-Hodgkin's lymphomas, Hodgkin's disease, bone and soft tissue sarcomas in the pediatric age group by polyethylene glycol (PEG) precipitation and latex agglutination inhibition (LAI) techniques. Results were compared with 25 age-matched controls. Highly significant CIC values were obtained by LAI technique (P less than 0.01) as compared to PEG pptn technique (P less than 0.05) in malignancy. However, seropositivity for CIC in lymphomas and Hodgkin's disease was 85.71 per cent by LAI test as compared to 57.14 per cent by PEG pptn test. In sarcoma group, seropositivity for CIC was 57.11 per cent by LAI test and 28.57 per cent by PEG pptn test. Combination of both these tests increases the sensitivity of immune complex detection in serum of cancer patients. CIC begin to rise in serum in early stages of neoplastic transformation, and the level of CIC is directly proportional to proliferating tumour mass in vivo.

In 1990, we isolated 158 strains of Salmonella typhi from blood cultures of patients suffering from typhoid fever. Seventy nine (50%) of these isolates were found to be simultaneously resistant to chloramphenicol, ampicillin and cotrimoxazole. These strains were also resistant to streptomycin and tetracycline, but sensitive to gentamicin, amikacin and cephalexin. The minimum inhibitory concentrations of chloramphenicol and trimethoprim for a representative number of these strains were found to be greater than 1024 micrograms/ml and greater than 128 micrograms/ml respectively. Majority of the multidrug resistant (MDR) strains tested against cefotaxime (23/23), ciprofloxacin (38/38) and amoxycillin plus clavulanic acid (23/24) were sensitive to these drugs.

Multifilament nylon fibers were made antibacterial by dopping with iodine. Nylon fibers were immersed in acetone solution of iodine for 48 hours at room temperature for dopping of iodine. It was observed that iodine uptake by the nylon fibers increased with the increase in concentration of iodine in the solution. Antibacterial activity of these iodine dopped samples was evaluated by measuring the zone of inhibition. The bacterial species used for this study were Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Klebsiella pneumoniae. Iodine dopped fibers exhibited good antibacterial activity against these bacterial species. Release of iodine in distilled water is sustained for about 30 days. Antibacterial activity of the fibers decreases with the release of iodine in water. Ultra-violet and visible spectroscopic studies showed that tri-iodide ions were released from the dopped samples in the aqueous medium. These I3- ions might be responsible for the observed antibacterial activity. Fiber shrinks on iodine dopping leading to increase in the denier of the fiber. However effect of iodine dopping on the breaking load of fibers is not significant.

A number of 5-substituted derivatives of Ranbezolid, a novel oxazolidinone were synthesized. Antibacterial activity of the compounds against a number of sensitive and resistant bacteria showed promising results.

Several potent oxazolidinone antibacterial agents were obtained by systematic modification of the linker between the five-membered heterocycle and the piperazinyl ring of RBx 7644 (Ranbezolid, 1) and its thienyl analogue 2, leading to the identification of an expanded spectrum compound RBx 8700 (6b).

Oxazolidinones are a new class of totally synthetic antibacterial agents with wide spectrum of activity against a variety of clinically significant susceptible and resistant bacteria. These compounds have been shown to inhibit translation at the initiation phase of protein synthesis. DuP-721, the first oxazolidinone showed good activity against M. tuberculosis when given orally or parenterally to experimental animals but was not developed further due to lethal toxicity in animal models. Later two oxazolidinones, PNU-100480 and Linezolid, demonstrated promising antimycobacterial activities in the murine model. While Linezolid has been approved for clinical use, PNU-100480 was not been developed further. DA- 7867 showed good in vitro and better in vivo efficacy than Linezolid but was poorly tolerated in rat toxicology studies. The antimycobacterial activity of AZD-2563 has not been explored. RBx 7644 had modest antimycobacterial activity while RBx 8700 has potent antibacterial and concentration dependent activity against all slow growing mycobacteria. It demonstrated better activity than RBx 7644 against MDR strains of M. tuberculosis along with intracellular activity. Toxicity, especially myelosuppression, has been an important limiting factor for development of an oxazolidinones. The GM-CSF assay has helped in selecting molecules with less myleosuppressive potential. We report, a review on the promising antituberculosis activities of the class oxazolidinones.

Purpose: In resource-constrained laboratories of developing countries determination of antifungal susceptibility testing by NCCLS/CLSI method is not always feasible. We describe herein a simple yet comparable method for antifungal susceptibility testing. Methods: Reference MICs of 72 fungal isolates including two quality control strains were determined by NCCLS/CLSI methods against fluconazole, itraconazole, voriconazole, amphotericin B and cancidas. Dermatophytes were also tested against terbinafine. Subsequently, on selection of optimum conditions, MIC was determined for all the fungal isolates by semisolid antifungal agar susceptibility method in Brain heart infusion broth supplemented with 0.5% agar (BHIA) without oil overlay and results were compared with those obtained by reference NCCLS/CLSI methods. Results: Comparable results were obtained by NCCLS/CLSI and semisolid agar susceptibility (SAAS) methods against quality control strains. MICs for 72 isolates did not differ by more than one dilution for all drugs by SAAS. Conclusions: SAAS using BHIA without oil overlay provides a simple and reproducible method for obtaining MICs against yeast, filamentous fungi and dermatophytes in resource-constrained laboratories.

RBx 8700, an investigational oxazolidinone, has excellent activity against respiratory pathogens. We evaluated the In Vitro minimum inhibitory concentration (MIC) and bactericidal activity of RBx 8700 against Mycobacterium tuberculosis and Mycobacterium avium complex (MAC) isolates. RBx 8700 had an MIC of 1 μg/ml against M. tuberculosis isolates resistant to both isoniazid (INH) and rifampicin (RIF), whereas its MIC against M. tuberculosis isolates resistant to either INH or RIF was 0.5 μg/ml.

Purpose: The purpose of this study was to evaluate three methods for detection of biofilm formation in staphylococci. Methods: For detection of biofilm formation, 152 clinical isolates of Staphylococcus spp. were screened by tissue culture plate (TCP), Tube method (TM) and Congo red agar (CRA) method. Results: Of the 152 Staphylococcus spp. 88(57.8%) displayed a biofilm-positive phenotype under the optimized conditions in the TCP method and strains were further classified as high 22 (14.47 %) and moderate 60 (39.4 %) while in 70 (46.0 %) isolates weak or no biofilm was detected. Though TM correlated well with the TCP test for 18 (11.8 %) strongly biofilm producing strains, weak producers were difficult to discriminate from biofilm negative isolates. Screening on CRA does not correlate well with either of the two methods for detecting biofilm formation in staphylococci. Conclusion: The TCP method was found to be most sensitive, accurate and reproducible screening method for detection of biofilm formation by staphylococci and has the advantage of being a quantitative model to study the adherence of staphylococci on biomedical devices.

Adhesion to biomaterial is assumed to be a crucial step in the development of staphylococcal foreign body infections. Production of extracellular slime has major implications for the development and implementation of therapeutic strategies. The effect of extracted slime was investigated on the activity of vancomycin, teicoplanin, linezolid, quinupristin/dalfopristin, rifampicin and ranbezolid against 10 clinical and 4 ATCC staphylococcal isolates. The slime extract caused a 2- to 16-fold increase in the MICs of vancomycin and teicoplanin, with a shift in the MIC(90) from 2 to 32 (vancomycin) and 2 to 16 (teicoplanin), whereas the MICs of linezolid and quinupristin/dalfopristin were only moderately affected. In time-kill studies, a significant decrease in bacterial killing (3 log(10) cfu/ml) was observed with vancomycin and teicoplanin (4 x MIC) after addition of slime (5 and 20 mg/ml), whereas the effect of killing by linezolid and quinupristin/dalfopristin was very modest. The rifampicin and ranbezolid MICs and kill curves were not influenced by the addition of slime. The present study thus indicated that slime interferes with the antimicrobial effect of glycopeptide drugs (vancomycin, teicoplanin), and that for effective prevention and treatment of prosthetic device-related infections, appropriate and newer antibiotics such as ranbezolid should be considered.