Bacteriophage therapy of human-restricted Salmonella species-a study in a surrogate bacterial and animal model.

Salmonella Typhi has been an important human-restricted pathogen from time immemorial, and unfortunately, the indiscriminate use of antibiotics has induced the emergence of multidrug resistance in S. Typhi. Bacteriophage therapy may be a possible alternative in countering antimicrobial resistance. Therefore, this study was planned to assess the efficacy of bacteriophages in treating acute and chronic S. Typhimurium infection in the mouse as a surrogate model. We isolated bacteriophages against S. Typhimurium and selected three different bacteriophages for the in vivo experiments. The lethal dose of S. Typhimurium was decided for Swiss albino mice, and acute infection was developed. Further, bacteriophage therapy by daily intraperitoneal injection of phage cocktail was given for 14 days. While the chronic carrier state of S. Typhimurium in Swiss albino mice was developed by inoculating intraperitoneally sequential 10-fold increasing doses of the bacterium. On the successful establishment of carrier state, oral feeding of phage cocktail at a high count was given, which completely cured the carrier state within 7 days of feeding. These experiments confirmed that the phage cocktail could eradicate the S. Typhimurium from the mice in both types of infections, that is acute and chronic.

Bacteriophages: A possible solution to combat enteropathogenic Escherichia coli infections in neonatal goats.

Due to awareness and benefits of goat rearing in developing economies, goats' significance is increasing. Unfortunately, these ruminants are threatened via multiple bacterial pathogens such as enteropathogenic Escherichia coli (EPEC). In goat kids and lambs, EPEC causes gastrointestinal disease leading to substantial economic losses for farmers and may also pose a threat to public health via the spread of zoonotic diseases. Management of infection is primarily based on antibiotics, but the need for new therapeutic measures as an alternative to antibiotics is becoming vital because of the advent of antimicrobial resistance (AMR). The prevalence of EPEC was established using bfpA gene, uspA gene and Stx1 gene, followed by phylogenetic analysis using Stx1 gene. The lytic activity of the isolated putative coliphages was tested on multi-drug resistant strains of EPEC. It was observed that a PCR based approach is more effective and rapid as compared to phenotypic tests of Escherichia coli virulence. It was also established that the isolated bacteriophages exhibited potent antibacterial efficacy in vitro, with some of the isolates (16%) detected as T4 and T4-like phages based on gp23 gene. Hence, bacteriophages as therapeutic agents may be explored as an alternative to antibiotics in managing public, livestock and environmental health in this era of AMR.

Antimicrobial assay and genetic screening of selected freshwater Cyanobacteria and identification of a biomolecule dihydro-2H-pyran-2-one derivative.

AIMS: Explorations of freshwater Cyanobacteria as antimicrobial (bacteria, fungi and methicillin-resistant Staphylococcus aureus (MRSA) strains) drug resource using bioassay, NRPS (non-ribosomal polypeptide synthetase) and PKS (polyketide synthase) genes, as well as in silico approach. METHODS AND RESULTS: We have bioassayed the extracts of Phormidium CCC727, Geitlerinema CCC728, Arthrospira CCC729, Leptolyngbya CCC732, Phormidium CCC730, Phormidium CCC731 against six pathogenic bacteria comprising Gram (+ve): S. aureus including seven clinical MRSA and Enterococcus faecalis, Gram (-ve): Escherichia coli, Salmonella Typhimurium, Klebsiella pneumoniae and Shigella boydii along with non-pathogenic Enterobacter aerogenes as well as fungal strains (Cryptococcus neoformans and Candida albicans, C. krusei, C. tropicalis and Aspergillus niger) exhibiting antimicrobial potential. The NRPS and PKS genes of the target strains were also amplified and sequenced. The putative protein structures were predicted using bioinformatics approach. CONCLUSION: PKS gene expression indicated ß keto-acyl synthase as one of the important active domains in the biomolecules related to antitumour and antifungal group. The simultaneous identification of the biomolecule (dihydro-2H-pyran-2-one derivative) was also inferred spectroscopically. SIGNIFICANCE AND IMPACT OF THE STUDY: Freshwater Cyanobacteria are prolific producers of secondary metabolite(s) that may act as the antimicrobial drug resource in addition to their much explored marine counterpart.

Curative effect of Terminalia chebula extract on acetic acid-induced experimental colitis: role of antioxidants, free radicals and acute inflammatory marker.

The present study has evaluated the healing effects of extract of dried fruit pulp of Terminalia chebula (TCE) on acetic acid (AA)-induced colitis in rats. TCE (600 mg/kg) showed healing effects against AA-induced colonic damage score and weight when administered orally daily for 14 days. TCE was further studied for its effects on various physical (mucus/blood in stool and stool frequency, food and water intake and body weight changes), histology, antibacterial activity and free radicals (NO and LPO), antioxidants (SOD, CAT and GSH) and myeloperoxidase in colonic tissue. Intra-colonic AA administration increased colonic mucosal damage and inflammation, mucus/bloody diarrhoea, stool frequency, but decreased body weight which were reversed by TCE and sulfasalazine (SS, positive control) treatments. TCE showed antibacterial activity and both TCE and SS enhanced the antioxidants, but decreased free radicals and myeloperoxidase activities affected in acetic acid-induced colitis. TCE indicated the presence of active principles with proven antioxidants, anti-inflammatory, immunomodulatory, and free radical scavenging and healing properties. Thus, TCE seemed to be safe and effective in healing experimental colitis.

Preparation and in vitro antibacterial evaluation of gatifloxacin mucoadhesive gellan system.

BACKGROUND AND THE PURPOSE OF THE STUDY: The poor bioavailability and therapeutic response exhibited by the conventional ophthalmic solutions due to precorneal elimination of the drug may be overcome by the use of mucoadhesive in situ gel forming systems that are instilled as drops into the eye and undergo a sol-gel transition in the cul-de-sac and have good mucoadhesion with ocular mucus layers. The objective of this study was to formulate ophthalmic mucoadhesive system of gatifloxacin (GTN) and to evaluate its in vitro antibacterial potential against, Staphylococcus aureus and Escherichia coli. METHODS: : Mucoadhesive systems were prepared using gellan combined with sodium carboxymethylcellulose (NaCMC) or sodium alginate to enhance the gel bioadhesion properties. The prepared formulations were evaluated for their gelation, and rheological behaviors, mucoadhesion force, in vitro drug release, and antibacterial activity. RESULTS: All formulations in non-physiological or physiological conditions showed pseudoplastic behaviors. Increase in the concentration of mucoadhesive agent enhanced the mucoadhesive force significantly. In vitro release of gatifloxacin from the mucoadhesive system in simulated tear fluid (STF, pH of 7.4) was influenced significantly by the properties and concentration of gellan, sodium carboxymethyl cellulose and sodium alginate. Significant reduction in the total bacterial count was observed between drug solution (control) and mucoadhesive batches against both tested organisms. MAJOR CONCLUSION: The developed mucoadhesive system is a viable alternative to conventional eye drops of GTN due to its ability to enhance bioavailability through its longer precorneal residence time and ability to sustain the release of the drug.

Evaluation of highly conserved hsp65-specific nested PCR primers for diagnosing Mycobacterium tuberculosis.

OBJECTIVE: To evaluate the sensitivity and specificity of a new nested set of primers designed for the detection of Mycobacterium tuberculosis complex targeting a highly conserved heat shock protein gene (hsp65). DESIGN: The nested primers were designed using multiple sequence alignment assuming the nucleotide sequence of the M. tuberculosis H37Rv hsp65 genome as base. Multidrug-resistant Mycobacterium species along with other non-mycobacterial and fungal species were included to evaluate the specificity of M. tuberculosis hsp65 gene-specific primers. RESULTS: The sensitivity of the primers was determined using serial 10-fold dilutions, and was 100% as shown by the bands in the case of M. tuberculosis complex. None of the other non M. tuberculosis complex bacterial and fungal species yielded any band on nested polymerase chain reaction (PCR). The first round of amplification could amplify 0.3 ng of the template DNA, while nested PCR could detect 0.3 pg. CONCLUSION: The present hsp65-specific primers have been observed to be sensitive, specific and cost-effective, without requiring interpretation of biochemical tests, real-time PCR, sequencing or high-performance liquid chromatography. These primer sets do not have the drawbacks associated with those protocols that target insertion sequence 6110, 16S rDNA, rpoB, recA and MPT 64.

Flow behind an exponential shock wave in a rotational axisymmetric perfect gas with magnetic field and variable density.

A self-similar model for one-dimensional unsteady isothermal and adiabatic flows behind a strong exponential shock wave driven out by a cylindrical piston moving with time according to an exponential law in an ideal gas in the presence of azimuthal magnetic field and variable density is discussed in a rotating atmosphere. The ambient medium is assumed to possess radial, axial and azimuthal component of fluid velocities. The initial density, the fluid velocities and magnetic field of the ambient medium are assumed to be varying with time according to an exponential law. The gas is taken to be non-viscous having infinite electrical conductivity. Solutions are obtained, in both the cases, when the flow between the shock and the piston is isothermal or adiabatic by taking into account the components of vorticity vector. The effects of the variation of the initial density index, adiabatic exponent of the gas and the Alfven-Mach number on the flow-field behind the shock wave are investigated. It is found that the presence of the magnetic field have decaying effects on the shock wave. Also, it is observed that the effect of an increase in the magnetic field strength is more impressive in the case of adiabatic flow than in the case of isothermal flow. The assumption of zero temperature gradient brings a profound change in the density, non-dimensional azimuthal and axial components of vorticity vector distributions in comparison to those in the case of adiabatic flow. A comparison is made between isothermal and adiabatic flows. It is obtained that an increase in the initial density variation index, adiabatic exponent and strength of the magnetic field decrease the shock strength.

Biochemical characterisation, enteropathogenicity and antimicrobial resistance plasmids of clinical and environmental Aeromonas isolates.

One hundred and eight strains of Aeromonas from clinical and environmental samples were speciated. Seven species were identified, the most prevalent of which was A. hydrophila. Experimental studies in an animal model with 36 representative strains of different species revealed that all strains could cause significant fluid accumulation in rabbit ileal loops. Of 107 strains showing single or multiple antimicrobial resistance, the highest incidence of resistance was shown for beta-lactam antibiotics other than cefotaxime. Transferable resistance plasmids, encoding resistance to ampicillin, cephalexin, cefoxitin, erythromycin and furazolidone, either alone or in combination, were detected in 35 strains. A further proportion of strains could be cured of one or more resistance markers, including resistance to nalidixic acid, and this was accompanied by the loss of plasmid DNA. The plasmids ranged in size between 85.6 and > 1 50 kb.

Chronic typhoid carriage and carcinoma of the gallbladder.

Chronic microbial infections and/or their carrier state have been reported to be associated with particular cancers. Since typhoid infections and carcinoma of the gallbladder (the site where salmonella usually persists) are endemic in northern India, it was considered important to explore the relationship between the two. In the present study, a total of 1001 bile specimens collected from cases of carcinoma of the gallbladder (28), cholelithiasis (56) and individuals without biliary pathology (17) were subjected to aerobic cultures that had been enriched for salmonella. Salmonella typhi and S. paratyphi-A could be detected in a significantly higher (P < 0.05) number in patients with carcinoma of the gallbladder as compared with cholelithiasis and control groups. The existence of such an association indicates that detection and eradication of typhoid carriers may lead to a decrease in the incidence of carcinoma of the gallbladder along with typhoid fever.

Interaction of endosulfan and metepa in rats.

Repeated administration of endosulfan or metepa or their mixture did not induce any significant histological changes in the organs examined in male rats. Similarly, the activity of different enzymes assayed here showed no significant alterations. The level of endosulfan did not differ significantly in presence or absence of metepa in the samples of blood, brain, fatty tissue, kidney, liver and testis. The observations do not suggest any kind of additive or antagonistic effects or potentiation of each compound in presence of the other, at the doses and duration studied in male rats.

Synthesis, antibacterial, antifungal and anti-HIV activities of norfloxacin mannich bases.

Mannich bases of norfloxacin were synthesized by reacting them with formaldehyde and several isatin derivatives. Their chemical structures have been confirmed by means of their IR, 1H-NMR data and by elemental analysis. Investigation of in vitro antimicrobial activity of compounds was done by the agar dilution method against 28 pathogenic bacteria, eight pathogenic fungi and anti-HIV activity against replication of HIV-1 (III B) in MT-4 cells. The in vivo antibacterial efficacy of selected derivatives was determined using a mouse infection model. All the synthesized compounds are more active than norfloxacin against the 13 bacteria tested. The compounds are also more active than the standard drug clotrimazole against Histoplasma capsulatum. Two compounds S-8 and S-9 have shown inhibition against HIV-1 (III B) with EC(50) values of 11.3 and 13.9 microgram/mL, respectively. In the mouse protection test, two compounds S-4 (ED(50): 1.25 mg/kg) and S-9 (ED(50): 1.62 mg/kg) are more active than norfloxacin (ED(50): 6mg/kg). Among the compounds tested, 1-ethyl-6-fluoro-1, 4-dihydro-4-oxo-7[[N(4)-[5'-bromo-3'-(4'-amino-5'-trimethoxybenzylpyr imidin-2'-yl]-imino-1'-isatinyl]methyl]N(1)-piperazinyl]-3-q uinoline carboxylicacid (S-9) showed promising activity in all the three tests.

Synthesis, antibacterial, antifungal and anti-HIV activities of Schiff and Mannich bases derived from isatin derivatives and N-[4-(4'-chlorophenyl)thiazol-2-yl] thiosemicarbazide.

Isatin, its 5-chloro and 5-bromo derivatives have been reacted with N-[4-(4'-chlorophenyl)thiazol-2-yl] thiosemicarbazide to form Schiff bases and the N-Mannich bases of these compounds were synthesized by reacting them with formaldehyde and three secondary amines. Their chemical structures have been confirmed by means of IR, 1H-NMR data and by elemental analysis. Investigation of antimicrobial activity of compounds was done by agar dilution method against 28 pathogenic bacteria, 8 pathogenic fungi and anti-HIV activity against replication of HIV-1 (IIIB) in MT-4 cells. Among the compounds tested 1-[N,N-dimethylaminomethyl]-5-bromo isatin-3-{1'-[4"-(p-chlorophenyl) thiazol-2"-yl] thio semicarbazone} 10 showed the most favourable antimicrobial activity.

Effect of intrathecal saline injection and Valsalva maneuver on cerebral perfusion pressure during transsphenoidal surgery for pituitary macroadenoma.

Cerebrospinal fluid pressure (CSFP) was monitored through a lumbar intrathecal catheter in 32 patients undergoing transsphenoidal excision of pituitary macroadenomas. In the first 20 patients, standardized intermittent Valsalva maneuvers were followed by intrathecal saline injections in 2.5-ml increments. Their effects on CSFP, mean arterial pressure (MAP), and therefore, cerebral perfusion pressure (CPP) were compared. The increase in CSFP produced by one Valsalva maneuver (4 +/- 2 mm Hg) was similar to that produced by a single increment of intrathecal saline (4 +/- 2 mm Hg), but the effect of saline was more sustained. With Valsalva maneuvers, the maximum CSFP produced was 13 +/- 4 mm Hg, and the CPP decreased to 50 +/- 14 mm Hg, whereas with saline, the maximum CSFP was 25 +/- 7 mm Hg, and the CPP decreased to 59 +/- 13 mm Hg. Because the increase in CSFP was greater and better sustained with intrathecal saline, Valsalva maneuvers were omitted in the next 12 patients. Peroperative data, including surgical conditions, and post-operative morbidity, with special reference to low-pressure headache and meningeal infection, were analyzed in all 32 patients. Operative conditions produced with intrathecal saline were judged excellent or good in 75% of patients. However, because this technique can decrease the CPP excessively, we recommend that it be used only with continuous CSFP monitoring.

Childhood diarrhoea due to rotavirus in a community.

The etiologic role of rotavirus in acute diarrhoeal illness in children under five years of age was studied over a period of one year in an urban slum community. Rotavirus was detected in 17.7 per cent of 376 children with diarrhoea and 4 per cent of 299 healthy children with maximum prevalence at 19-24 months of age with statistically comparable detection in 0-6 months of age. The overall prevalence was significantly higher in children below 2 yr as compared to those between 2-5 yr of age. Girls (24.1%) were more susceptible amongst the diarrhoeal group in comparison to boys (13.8%). Diarrhoea due to rotavirus was more prevalent during the cooler months (November-February) of the year and no correlation was observed with rainfall and relative humidity. Rotavirus as the sole pathogen was observed in 9 per cent children with diarrhoea and in the rest, association of Cryptosporidium (3%) was observed for the first time with this virus along with other known enteropathogenic bacteria and parasites, enterotoxigenic Escherichia coli being the commonest organism.

Single small enhancing computed tomographic (CT) lesions in Indian patients with new-onset seizures. A prospective follow-up in 75 patients.

This study was planned to observe the clinical and radiological course of single small enhancing CT lesions in Indian patients presenting with new-onset-seizures. In this study, 75 patients with new-onset seizures and a single enhancing CT lesion were prospectively followed up for 1 year. All patients fulfilled the criteria of cysticercus granuloma. The repeat CT scans were performed 2 months after the first CT scan. Antiepileptic drug therapy was the only form of treatment given. The majority of patients were below 20 years of age. Simple partial seizure, with or without secondary generalization, was the commonest type of seizure encountered in these patients. In follow-up CT scans 84% of patients showed either disappearance or regression in the size of lesion. The proportion of patients showing complete disappearance of CT lesions was 0.73 (95% CI, 0.61-0.80). In 11 (15%) patients the lesions were calcified. In nine patients, in whom the lesion had persisted or regressed, another follow-up CT scan (6 months after the second scan) revealed either complete disappearance or calcification of the lesions. The majority (86.6%) of patients remained seizure free for 1 year after starting antiepileptic drugs. Ten patients experienced seizure recurrences within the first month of therapy. The proportion of patients who remained seizure free was 0.86 (95% CI, 0.76-0.92). Four patients experienced seizure recurrence even after complete disappearance of CT lesions. In the majority of patients the lesions disappeared spontaneously and in a few the lesions calcified; hence these patients did not require anticysticercal therapy. Antiepileptic therapy was helpful in controlling further recurrences of seizures in most of the patients. A few patients experienced seizures even after disappearance of CT lesions.

Synthesis and antimicrobial activity of Schiff and Mannich bases of isatin and its derivatives with pyrimidine.

Isatin and its derivatives have been reacted with 4-(4'-chlorophenyl)-6-(4"-methyl phenyl)-2-aminopyrimidine to form Schiff bases and the N-Mannich bases of these compounds were synthesized by reacting them with formaldehyde and several secondary amines. Investigation of antimicrobial activity of the compounds was made by the agar dilution method against 28 pathogenic bacteria, eight pathogenic fungi and anti-HIV activity against replication of HIV-1 (III B) in MT-4 cells. The compounds are significantly active against bacteria and fungi.

14C-urea breath test for assessment of gastric Helicobacter pylori colonization and eradication.

BACKGROUND AND OBJECTIVE: Urea breath test (UBT) is a reliable noninvasive technique for detecting gastric Helicobacter pylori colonization. 14C isotope-based test requires simple equipment and is inexpensive. We studied the utility of 14C-UBT in diagnosis of gastric H. pylori infection. METHODS: Presence of H. pylori was studied using antral histology and culture in patients with rapid urease test (RUT)-positive peptic ulcer. 14C-UBT was performed using a 185-kBq dose. Radioactivity in 15-min breath samples was measured using a beta-scintillation counter and result expressed as % dose recovered/mmol CO2. H. pylori was considered positive when any two tests were positive. All tests were repeated one month after completion of H. pylori eradication therapy. RESULTS: Among 41 patients (duodenal ulcer 36, gastric ulcer 5), H. pylori was detected by histology in 23 (56%) and by culture in 27 (66%). Overall, H. pylori was detected in 28 (68%) patients. Follow-up assessment was possible in 28 patients: 26 cleared the infection (all three tests negative). Mean 14C recovery values at 15 minutes associated with H. pylori-positive status were significantly higher (12.3 [SD 6.8] x 10(-3); n=30; p<0.001) than those associated with H. pylori-negative status (2.1 [0.9] x 10(-3); n=26). Using receiver-operating-characteristic analysis of 15-minute 14C recovery values, a cut-off of 6.5x10(-3) gave the best separation of H. pylori-positive and -negative cases. 14C-UBT had 93% sensitivity, 96% specificity and 95% accuracy. CONCLUSION: 14C-UBT appears to be a reliable noninvasive test for diagnosis of H. pylori infection.

[Hemostasis with a new infrared-sapphire-coagulator (ISC-81). First clinical studies]. / Blutstillung mit einem neuen Infrarot-Saphir-Coagulator (ISC-81) Erste klinische Erfahrungen.

A new infrared sapphire coagulator (ISC-81) has been developed for the hemostasis of parenchymatous hemorrhage. Upon absorption by the bleeding tissue, light is converted into thermal energy thus causing coagulation and hemostasis. The light is transmitted to the bleeding tissue via a sapphire crystal, which is nonadhesive and of high thermal resistance. For application on flat surfaces or in ruptured tissues, either a cylindrical or a wedge-shaped crystal can be used. Up to now the ISC-81 has been used successfully on 22 patients, most of whom had hemorrhages from ruptured spleens or livers.

Pharmacological actions of Pongamia pinnata roots in albino rats.

Pongamia pinnata root has been advocated in Ayurveda for treatment of various inflammatory and infective conditions including ulcers. Sequential petroleum ether, benzene, chloroform, acetone and ethanolic extracts of P. pinnata roots when administered in the dose of 50 mg/kg, i.p. in rats was found to have anti-inflammatory, analgesic activity while pentobarbitone-induced 'sleep time' was reduced by all the extracts except petroleum ether which, however, enhanced it. They were also found to possess antiulcer effects when administered either by i.p. (45 min before) or oral route (45 min before or for 4 days) against restraint-stress or pylorus-ligated gastric ulcers in rats, the maximum protection being afforded by petroleum ether and ethanol extracts. The mechanism of antiulcer effect could either be due to decrease in acid-pepsin secretion and augmentation of mucin secretion as observed with ethanol extract, while petroleum ether extract might be producing the effect by virtue of its anti-stress activity.