Advances in CGRP Monoclonal Antibodies as Migraine Therapy: A Narrative Review

Migraine is a potentially disabling disorder, yet it remains underdiagnosed and undertreated. The release of the neuropeptide calcitonin gene-related peptide (CGRP) in the trigemino-cerebrovascular system plays a vital role in the evolution of migraine. It enhances peripheral sensitization by mediating neurogenic inflammation and also influences central sensitization. The majority of the drug classes available for migraine prophylaxis are nonspecific and associated with numerous side effects and drug interactions. Anti-CGRP monoclonal antibodies (mAb) are an innovative therapeutic class that fulfills the need for more efficacious and tolerable preventive therapy. While erenumab is a mAb to the CGRP receptor, eptinezumab, fremanezumab, and galcanezumab bind to the CGRP molecule. They decrease the number of headache days and improve disability. Upper respiratory tract infection, nausea, constipation, pain at the site of injection, and fatigue are the associated side effects. CGRP mAbs are an excellent advancement in translational research and are a promising addition in migraine therapy. This article discusses the recent advances in the development of the CGRP mAbs.

Sclerostin inhibition: A novel target for the treatment of postmenopausal osteoporosis

Osteoporosis, a widespread skeletal disorder with a substantial economic load, is characterized by increased porosity of the bones resulting in vulnerability to fractures. When activated, the canonical Wnt signaling pathway results in osteoblastogenesis and bone formation. A Wnt ligand forms a complex with low-density lipoprotein receptor-related proteins 5 and 6 (Lrp5/6) and stimulates intracellular signaling cascades, leading to nuclear translocation of β-catenin and transcription of downstream molecules involved in osteoblast differentiation, maturation, and survival. Sclerostin (SOST), a glycoprotein produced by osteocytes, is an extracellular Wnt antagonist that blocks the binding of Wnt ligands to Lrp5/6, preventing the activation of the pathway and osteoblast-mediated bone formation subsequently. Inhibition of SOST represents a new therapeutic paradigm for the treatment of osteoporosis. Monoclonal antibodies to SOST include romosozumab, blosozumab, and setrusumab. With its unique dual effect of increasing bone formation (anabolic action) and decreasing bone resorption, the Food and Drug Administration approved romosozumab, a promising new treatment for postmenopausal osteoporosis. Its efficacy and safety have been established in trials. However, patients at high risk of cardiovascular or cerebrovascular events should not be prescribed romosozumab.

Cardiometabolic vigilance in COVID-19 and resource husbandry in resource-challenged times: Clinical practice- based expert opinion

BACKGROUND AND AIMS

The ongoing pandemic of coronavirus disease 2019 (COVID-19) is rapidly evolving, thereby posing a profound challenge to the global healthcare system. Cardiometabolic disorders are associated with poor clinical outcomes in persons with COVID-19. Healthcare challenges during the COVID-19 pandemic are linked to resource constraints including shortage of Personal Protective Equipment's (PPE), laboratory tests and medication. In this context, a group of clinical experts discussed the endocrine and cardiology vigilance required in times of COVID-19. Further, the group proposed certain resource husbandry recommendations to be followed during the pandemic to overcome the constraints.

METHOD

The clinical experts discussed and provided their inputs virtually. The expert panel included clinical experts comprising endocrinologists, Consultant Physicians and cardiologists from India. The panel thoroughly reviewed existing literature on the subject and proposed expert opinion.

RESULTS

The expert panel put forward clinical practice-based opinion for the management of cardiometabolic conditions including diabetes mellitus and hypertension. As these conditions are associated with poor clinical outcomes, the expert panel recommends that these persons be extra-cautious and take necessary precautions during the ongoing pandemic. Further, experts also provided appropriate, affordable, available and accessible solution to the resource constraint situations in times of COVID-19 pandemic.

CONCLUSION

The clinical expert opinion put forward in this article will serve as a reference for clinicians treating diabetes and cardiovascular disease during the COVID-19 pandemic.

Spectrum of Presentation of Anorectal Malignant Melanoma: Experience of a Tertiary Care Centre of North India

Malignant melanoma of the anorectum is a rare but highly aggressive tumor. We report our experience of anorectal melanoma in five patients. Of these, two have advanced disease, two had localized disease and one patient had florid systemic metastases with a history of hemorrhoidectomy one year prior. One patient whose metastatic workup was negative, expired on post-op day 15 of abdominoperineal resection due to unsuspected but florid cerebral metastases. Another patient with localized disease underwent an APR with curative resection and post-op whole body PET scan negative for occult or residual disease. Advanced stage patients were referred for chemotherapy. To improve prognosis, it is important to detect anorectal melanoma at an early stage.

Vismodegib: A smoothened inhibitor for the treatment of advanced basal cell carcinoma

Incidence of basal cell carcinoma (BCC), the most common skin cancer in humans, is rising. Surgery is the mainstay of treatment but there is no standard of care for locally advanced or metastatic disease. Hedgehog signaling proteins are critical for cell growth and differentiation during embryogenesis; Hh pathway is silenced in adults. Dysregulated or aberrant Hh signaling has been implicated in the pathogenesis of BCC. This hyperactive pathway can be inhibited by use of smoothened inhibitors such as vismodegib. Food and drug administration approved this oral, once-daily medication in 2012 to treat adults with metastatic BCC or locally advanced, recurrent BCC after surgery and also for patients with locally advanced BCC who are not candidates for surgery or radiation treatment. Clinical studies have shown it to be highly efficacious and the most common adverse effects include, muscle spasms, alopecia and dysgeusia. Use of targeted biologic modifiers, exemplified by Hh directed therapeutics offer a new hope to patients with high-surgical morbidity or inoperable tumors.

In VitroBactericidal Activity of Oxazolidinone, RBx 8700 againstMycobacterium tuberculosisandMycobacterium avium complex

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 gLg/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 microg/ml.

Vaptans: A new option in the management of hyponatremia

Arginine vasopressin (AVP) plays an important role in water and sodium homeostasis. It acts via three receptor subtypes-V1a, V1b, and V2-distributed widely throughout the body. Vaptans are nonpeptide vasopressin receptor antagonists (VRA). By property of aquaresis, VRAs offer a novel therapy of water retention. Conivaptan is a V1a/V2 nonselective VRA approved for euvolemic and hypervolemic hyponatremia. Tolvaptan is the first oral VRA. Other potential uses of this new class of drugs include congestive heart failure (CHF), cirrhosis of liver, syndrome of inappropriate secretion of antidiuretic hormone, polycystic kidney disease, and so on. These novel drugs score over diuretics as they are not associated with electrolyte abnormalities. Though much remains to be elucidated before the VRAs are applied clinically, the future holds much promise.

Istaroxime: A rising star in acute heart failure

Heart failure in India is a growing epidemic. Around 30 to 40% of patients die from heart failure within one year of receiving the diagnosis. Currently available inotropes have not only failed to show consistent results but are also associated with adverse outcomes. Istaroxime is a novel intravenous agent with luso-inotropic properties that acts by inhibition of Na⁺/K⁺ adenosine triphosphatase and stimulation of sarco/ endoplasmic reticulum calcium ATPase isoform 2. In clinical studies, it significantly decreased left ventricular end diastolic pressure, pulmonary capillary wedge pressure, heart rate and increased systolic blood pressure and cardiac index with no change in neurohormones, renal function or troponin I. Istaroxime is a promising alternative for patients presenting with acute heart failure syndrome for whom the therapeutic options are currently limited.

Spinosad: An effective and safe pediculicide

Although head lice are not a major health hazard, they have been a source of irritation and disgust for thousands of years. Despite the use of over-the-counter (OTC) treatments, it has high prevalence, and epidemics occur regularly. Permethrin 1% is currently recommended as a drug of choice, but many areas have shown resistance to this insecticide. A 0.9% suspension of spinosad, a naturally occurring pest control product, has recently been approved by the USFDA for treatment of pediculosis capitis. It acts by enhancing the action of nicotinic acetylcholine, resulting in paralysis of the parasite. Clinical trials show that spinosad is more effective and safe than current drugs of treatment. Additionally, it does not require nit combing. Spinosad appears as a powerful recruit in the battle against head lice.

Early onset primary pulmonary cryptococcosis in a renal transplant patient

We report a case of primary pulmonary cryptococcosis in a post-renal transplant patient. A 65-year-old male renal transplant patient was admitted to the hospital with a low grade fever of 1 month, radiologically mimicking tuberculosis (TB). Broncho-alveolar fluid (BAL) shows capsulated yeast, and Cryptococcus neoformans was grown on culture supported by cytology and histopathological examination. Cryptococcal antigen was positive (32-fold) in serum and was negative in cerebrospinal fluid (CSF). The patient was given amphotericin B and 5-flucytosine and clinical improvement was seen on a weekly follow up. The serum cryptococcal antigen test might contribute to the early detection and treatment of pulmonary cryptococcosis. The results of antifungal susceptibility were aid in selecting the drug of choice for treatment.

Effect of oxazolidinone, RBx 7644 (ranbezolid), on inhibition of staphylococcal adherence to plastic surfaces

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.

Antimycobacterial activities of oxazolidinones: a review

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.

Antifungal susceptibility testing method for resource constrained laboratories

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.

Detection of biofilm formation among the clinical isolates of Staphylococci: an evaluation of three different screening methods

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.

Activity of blue green microalgae extracts against in vitro generated Staphylococcus aureus with reduced susceptibility to vancomycin

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 mug/ml.

Detection of vancomycin resistant Staphylococcus aureus: a comparative study of three different phenotypic screening methods

The objective of this study was to investigate screening methodologies, to detect Staphylococcus aureus strains with decreased susceptibility to vancomycin. Three methods were used to screen 160 Staphylococcus aureus clinical isolates along with ATCC quality control strains. Subsequently, MIC of all these 160 strains were determined by NCCLS methodology. The MIC of all the 160 clinical isolates was < or = 4 microg/mL and were classified as vancomycin susceptible by NCCLS criteria but 23 strains were positive by Hiramatshu method, two grew on MHA (5 microg/mL vancomycin) while CDC method correctly identified no vancomycin intermediate S.aureus (VISA) or vancomycin resistant S.aureus (VRSA) strains with reference to there MIC. CDC method was found to be the most appropriate screening methodology for detection of VISA or VRSA for diagnostic laboratories.

Evaluation of Methods for AmpC Beta-Lactamase in Gram Negative Clinical Isolates from Tertiary Care Hospitals

The purpose of this study was to simultaneously screen for Extended-spectrum beta-lactamases (ESBL) and AmpC beta-lactamases in gram negative clinical isolates from four tertiary care hospitals and further to compare two detection methods three-dimensional extraction method and AmpC disk test for AmpC beta-lactamases. A total of 272 isolates were screened for ESBL and AmpC beta-lactamase by modified double disk approximation method (MDDM). Synergy observed between disks of ceftazidime/cefotaxime and clavulanate were considered as ESBL producer. Isolates showing reduced susceptibility to either of the test drugs (ceftazidime or cefotaxime) and cefoxitin were considered as presumptive AmpC producers and further confirmed by three-dimensional extraction method and AmpC disk test. A total of 173 (64%) of the isolates were found to be ESBL positive and 61 (23%) showed resistant to cefoxitin. ESBL was detected in 80 (62%) isolates of E. coli and 71 (73%) of Klebsiella spp. The occurrence of AmpC beta-lactamases was found to be 8% (22) of the total isolates and the two detection methods for AmpC beta-lactamase showed concordant results. Screening for ESBL and AmpC can be simultaneously done by MDDM method and confirmation for AmpC beta-lactamase should be carried out routinely in tertiary care hospitals by AmpC disk test, as it is a simple and rapid procedure.

Fluconazole and itraconazole susceptibility of clinical isolates of Cryptococcus neoformans at a tertiary care centre in India: a need for care

OBJECTIVES

In cryptococcosis, fluconazole is a standard prophylactic, therapeutic and maintenance option, particularly in the expanding HIV/AIDS group. However, its excessive use may lead to resistance in Cryptococcus neoformans. Variations in clinical response to fluconazole have already been noted elsewhere, and cases of post-therapy relapse are not uncommon. To assess azole antifungal susceptibility profiles of clinical cryptococcal isolates in India, the All India Institute of Medical Sciences (AIIMS) has recently initiated preliminary studies using NCCLS M27-A.

MATERIALS AND METHODS

Twenty-eight randomly chosen AIIMS clinical isolates (spanning 1997-2000), 16 isolates from other institutions in North India, and six reference strains of C. neoformans were subjected to susceptibility testing to fluconazole and itraconazole.

RESULTS

Among clinical isolates, susceptibilities to fluconazole and itraconazole were 84.1% and 93.2%, respectively. MICs for all clinical isolates were 0.25-32 mg/L for fluconazole and <0.03-0.25 mg/L for itraconazole. MIC50 and MIC90 values for fluconazole were 4 and 16 mg/L, respectively, and those for itraconazole were 0.032 and 0.125 mg/L, respectively. Out of 28 AIIMS clinical isolates, 22 had minimum fungicidal concentrations (MFCs) of fluconazole at 128 mg/L. Moderately high fluconazole MICs (16-32 mg/L) were observed in 16% of clinical isolates--probably the first such report from India. MIC/MFC ratios for fluconazole and itraconazole were 1:32 or more in 16 AIIMS clinical isolates, indicating possible azole tolerance. There was good agreement between MIC values obtained by the micro- and macro-broth dilution techniques of M27-A compared in this study.

CONCLUSIONS

The observed MIC data warrant continued surveillance of susceptibility values of clinical cryptococcal isolates in India.

The effects of keratinocyte growth factor in preclinical models of mucositis

The epithelium of the oral cavity and small intestine of the gastrointestinal tract have a high rate of cell renewal and as such, are sensitive to cytotoxic therapies that kill rapidly dividing cells. Mucositis is a complication of cancer therapy where impairment of the regenerative capacity of the epithelium leads to atrophy, ulceration and a loss of barrier function. Keratinocyte growth factor (KGF) is an epithelial cell-specific growth and differentiation factor that is trophic for the mucosal epithelium of the gastrointestinal tract. In this study, KGF in normal animals caused epithelial thickening in the squamous epithelium of the oral cavity and increased crypt depth and villus height of the small intestine. It also appeared to regulate gene expression in these tissues including that of some antioxidant enzymes and intestinal trefoil protein. KGF has been shown to be efficacious in several preclinical models of mucositis where KGF pretreatment reduced weight loss typically seen during and after the course of therapy and significantly improved survival. At a tissue level KGF reduced atrophy, accelerated regrowth, and decreased ulcer formation of the oral epithelium after irradiation, and improved crypt survival and prevented villus atrophy in the small intestine of irradiated or chemotherapy-treated mice. Preliminary studies suggest that its efficacy may be partly a consequence of the growth and differentiation effect, and also partly due to regulation of the expression of genes that play a role in mucosal protection. These data suggest that KGF may be useful for the prevention or treatment of mucositis in patients treated with regimens of cancer therapy that have gastrointestinal toxicity.

Polyherbal formulations with wide spectrum antimicrobial activity against reproductive tract infections and sexually transmitted pathogens

PROBLEM

Recent reports indicate high incidence of genital infections, most of which are sexually transmitted. Although specific drugs and antibiotics are available for some, a safe spermicidal formulation with wide spectrum antimicrobial action would be a desirable addition to the presently available spermicides.

METHODS

Formulations at different dilutions were tested in culture systems on standard strains and clinical isolates including some isolates resistant to drugs. The effect on (HSV)-2 and Chlamydia trachomatis was determined in vivo in progestin sensitized mice. The effect on HIV-1 was investigated in two standardized systems.

RESULTS

Polyherbal cream inhibited the growth in culture of clinical isolates of Candida albicans, Candida krusei and Candida tropicalis. Both the polyherbal cream and the Praneem polyherbal pessary inhibited urinary tract Escherichia coli (including multidrug resistant strains), and Neisseria gonorrhoeae (including 2 strains resistant to penicillin). Both formulations manifested virucidal activity against HIV-1 at >2 and 50% dilutions (in two different test systems) on contact for 1-2 min. Intravaginal inoculation of the cream and the pessary suspensions before inoculation of the pathogen prevented lesions and vaginal transmission of HSV-2 and C. trachomatis in progestin sensitized mice.

CONCLUSIONS

Polyherbal formulations have wide spectrum antibacterial, antifungal and antiviral effect against the tested sexually transmitted pathogens.

A method for extraction of high-quality and high-quantity genomic DNA generally applicable to pathogenic bacteria

In this study, we report a modified procedure for extraction of high-quality genomic DNA that is rapid, simple, biologically nonhazardous, and generally applicable to pathogenic bacteria. Bacterial cells were pretreated with 70% ethanol prior to enzymatic digestion with lysozyme. Exposure of bacterial cells to 70% ethanol sterilized the cultures, making the process biologically safe and increased the susceptibility of the cells to lysozyme-induced lysis. Consistently high yields of genomic DNA (mean average yield, 0.5-2.5 mg/ml) were obtained from 465 isolates representing over 30 clinically important bacterial species. Genomic DNA obtained was determined to be suitable for further analysis, including bacterial fingerprinting techniques like restriction endonuclease analysis, Southern hybridization, and repetitive PCR. Availability of a generally applicable procedure for extraction of high-quality and high-quantity genomic DNA would be immensely beneficial for laboratories engaged in molecular surveillance of nosocomial and community-based outbreaks.

Mechanisms of resistance to fluoroquinolones

Fluoroquinolones have some of the properties of an 'ideal' anti-microbial agent. Because of their potent broad spectrum activity and absence of transferable mechanism of resistance or inactivating enzymes, it was hoped that clinical resistance to this useful group of drugs would not occur. However, over the years, due to intense selective pressure and relative lack of potency of the available quinolones against some strains, bacteria have evolved at least two mechanisms of resistance: (i) alteration of molecular targets, and (ii) reduction of drug accumulation. DNA gyrase and topoisomerase IV are the two molecular targets of fluoroquinolones. Mutations in specified regions (quinolone resistance-determining region) in genes coding for the gyrase and/or topoisomerase leads to clinical resistance. An efflux pump effective in pumping out hydrophilic quinolones has been described. Newer fluoroquinolones which recognize both molecular targets and have improved pharmacokinetic properties offer hope of higher potency, thereby reducing the probability of development of resistance.

Antibodies to Cag A protein are not predictive of serious gastroduodenal disease in Indian patients

OBJECTIVE

The present study was aimed at assessing the predictive utility of anti-Cag A antibodies in differentiating patients of duodenal ulcer (DU) and non ulcer dyspepsia (NUD) from asymptomatic controls in a developing country.

METHODS

Sera from 120 subjects were tested for antibodies to Cag A using the immunodominant portion of a recombinant 37.5 kDa fusion protein by ELISA, in endoscopically proven cases of DU and NUD and healthy controls.

RESULTS

The observed optical density (OD) in DU and NUD patients was 1,947 and 1,960 respectively, which was higher than that observed in controls (p < 0.01), but there was no difference in the anti-Cag A antibody titers between DU and NUD patients.

CONCLUSION

Anti-Cag A antibodies do not seem to discriminate duodenal ulcer patients from non ulcer dyspepsia in the Indian population.

Molecular genetic analysis of multi-drug resistance in Indian isolates of Mycobacterium tuberculosis

A total of 116 isolates from patients attending the out-patient department at the All India Institute of Medical Sciences, New Delhi and the New Delhi Tuberculosis Centre, New Delhi, India were collected. They were analyzed for resistance to drugs prescribed in the treatment for tuberculosis. The drug resistance was initially determined by microbiological techniques. The Bactec 460TB system was employed to determine the type and level of resistance in each isolate. The isolates were further characterized at molecular level. The multi-drug loci corresponding to rpo beta, gyr A, kat G were studied for mutation(s) by the polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) technique. The SSCP positive samples were sequenced to characterize the mutations in rpo beta, and gyr A loci. While previously reported mutations in the gyr A and rpo beta loci were found to be present, several novel mutations were also scored in the rpo beta locus. Interestingly, analysis of the gyr A locus showed the presence of point mutation(s) that could not be detected by PCR-SSCP. Furthermore, rifampicin resistance was found to be an important marker for checking multi-drug resistance (MDR) in clinical isolates of Mycobacterium tuberculosis. This is the first report on molecular genetic analysis of MDR tuberculosis from India, and highlights the increasing incidence of MDR in the Indian isolates of M. tuberculosis.

A comparative study of therapeutic response of patients with clinical chancroid to ciprofloxacin, erythromycin, and cotrimoxazole

BACKGROUND AND OBJECTIVES

Cotrimoxazole has traditionally been used as first drug for treatment of chancroid in India. With reports of increasing resistance to the drug, this study was conducted to compare treatment response of clinical chancroid between ciprofloxacin, 500 mg twice daily for 3 days, erythromycin, 500 mg four times daily for 7 days, and double-strength cotrimoxazole (trimethoprim 160 mg + sulfamethoxazole 800 mg), twice daily for 7 days.

STUDY DESIGN

Forty-six patients with a clinical diagnosis of chancroid were randomly divided into 3 groups. Sixteen patients received ciprofloxacin, whereas 15 each received erythromycin and cotrimoxazole. Patients were seen on day 7, 14, and if needed day 21. Clinical response was noted in terms of cure, improvement, or failure.

RESULTS

Excellent response was observed to both ciprofloxacin and erythromycin therapy with cure rates of 93.7% and 93.3%, respectively. Improvement was observed in 6.7% cases in both groups. There were no failures with either ciprofloxacin or erythromycin. Poor response to cotrimoxazole therapy was observed with 53.3% cure rates and a high failure rate of 46.7%.

CONCLUSION

Ciprofloxacin and erythromycin are equally effective in chancroid. Ciprofloxacin is better in terms of dosage schedule, duration of treatment, and low cost. Cotrimoxazole should be discontinued as drug of choice because of high failure rates.

Study of Pseudomonas aeruginosa causing ventilator associated pneumonia

Ps. aeruginosa is a frequent and prominent cause of nosocomial pneumonia especially in persons on assisted ventilation in the intensive care units. In a year long surveillance of ventilator associated pneumonia (VAP) we isolated 42 strains from broncho alveolar lavage samples collected and processed from 102 patients. By pyocin typing 40 of the 42 strains could be typed into 39 types but this designation changed each time the test was repeated. SDS-PAGE analysis of the whole cell proteins grouped the 42 strains of Ps. aeruginosa into 20 groups. After ribotyping, using an 18 mer DIG labelled oligonucleotide to the conserved region of 16S rRNA gene, the strains were designated into 18 types. The major type contained 8 isolates, but there was no clustering of isolates, indicating that each infecting strain was acquired separately and not from a common source. It would, therefore, appear that cross infection with a single clone was not the predominant mode of Ps. aeruginosa infection causing VAP in our ICU.

Multidrug-resistant Mycobacterium tuberculosis: molecular perspectives

Multidrug-resistant strains of Mycobacterium tuberculosis seriously threaten tuberculosis (TB) control and prevention efforts. Molecular studies of the mechanism of action of antitubercular drugs have elucidated the genetic basis of drug resistance in M. tuberculosis. Drug resistance in M. tuberculosis is attributed primarily to the accumulation of mutations in the drug target genes; these mutations lead either to an altered target (e.g., RNA polymerase and catalase-peroxidase in rifampicin and isoniazid resistance, respectively) or to a change in titration of the drug (e.g., InhA in isoniazid resistance). Development of specific mechanism-based inhibitors and techniques to rapidly detect multidrug resistance will require further studies addressing the drug and drug-target interaction.

Antigonadotrophic effect of Mycobacterium tuberculosis

The present investigation has been carried out to study if the Mycobacterium tuberculosis has any direct effect on granulosa cell progesterone production. Granulosa cells from pregnant mare serum gonadotropin (PMSG)-treated immature rats were incubated in replicates with and without the ultrasonicated Mycobacterium tuberculosis in the presence and absence of human chorionic gonadotrophin (hCG). Progesterone production and granulosa cell viability were assayed. The mycobacterial lysate significantly inhibited the basal production of progesterone. The lysate completely blocked the stimulatory effect of hCG. Any cytotoxic effect of the lysate was ruled out as none of the treatments decreased the viability of the granulosa cells as compared with the control values.

Role of circulating immune complexes in prognostic evaluation and management of genitourinary cancer patients

Circulating immune complexes (CIC) were estimated in 48 Patients of genitourinary cancer by polyethylene glycol precipitation (PEG pptn.) test and latex agglutination inhibition (LAI). The results were compared with 25 healthy control volunteers. Pathological levels of CIC were observed in 79.18 percent patients of genitourinary cancer by combination of PEG pptn. and LAI tests, while no seropositivity for CIC was observed in control group (p < 0.001). Sequential increase in seropositivity for CIC was observed with advancing stage of genitourinary cancer i.e. number of seropositive patients in cancer stage I were 60 percent, stage II-71.42 percent, stage III-85.71 percent and stage IV-100 percent. Variation IN CIC levels in different patients within the same stage are compared. Circulating antigen antibody complexes have a significant role as prognostic monitors in management of genitourinary cancer patients. Statistical evaluation of data on intra- and inter-assay variation has been given. CIC levels rise with increases in tumor burden in vivo hence variation in CIC levels within the same stage in different patient have a significant role as prognostic monitors in management of individual patients.

Eradication of H. pylori in a developing country: comparison of lansoprazole versus omeprazole with norfloxacin, in a dual-therapy study

OBJECTIVES

Lansoprazole, a newer benzimidazole, is more potent than omeprazole in its anti-Helicobacter pylori effect in vitro. The present study was aimed at assessing its efficacy in a developing country.

METHODS

Fifty patients were randomized to receive either lansoprazole or omeprazole, with norfloxacin for 2 wk; the ulcer healing rates, H. pylori eradication rates, and recurrence rates were compared over a 6-month period.

RESULTS

Both lansoprazole and omeprazole were equally effective in inducing healing of ulcer (96.1 vs 95.5%, p > 0.05) and eradicating H. pylori (76.9 vs 63.9%, p > 0.05), with very low recurrence rates over a 6-month follow-up period.

CONCLUSIONS

Either lansoprazole or omeprazole combined with norfloxacin is effective in eradicating H. pylori in a high percentage of cases of duodenal ulcer, with little difference between the two proton pump inhibitors.

Comparative evaluation of two indigenously developed tests for rapid detection of group-A streptococci directly from throat swabs

The efficacy of two indigenously developed rapid tests, latex agglutination and antibody capture assay (a colour immunochromatographic assay) to detect group A Streptococcus pyogenes (GAS) was evaluated in comparison with the traditional culture method ('Gold Standard') in both asymptomatic children (1500) and symptomatic patients (233). Throat swabs were taken in duplicate and rapid tests performed on one swab and culture on the other. Both latex agglutination and antibody capture assays showed a sensitivity of 100 per cent and specificity of > 98 per cent as compared to culture and isolation in symptomatic patients. However, among asymptomatic carriers sensitivity of 100 per cent and 87.5 per cent and specificity > 95 per cent were observed for latex agglutination and antibody capture assays respectively. Latex agglutination showed no false negative results and sensitivity was not affected by low beta-haemolytic counts in asymptomatic children. The rapid tests described here will help in the detection and thereby the management of GAS infection.

Legionella as a lower respiratory pathogen in north India

One hundred patients of lower respiratory tract infection (LRTI) were prospectively studied over 2 years to find out if Legionella is a causative agent in these patients. In addition, 50 environmental samples and 50 age and sex matched controls were studied. Culture and direct fluorescent antibody testing (DFA) of respiratory tract secretions, and serodiagnosis by indirect immunofluorescence (IIF) and ELISA, were employed to detect Legionella. Respiratory tract secretions from all patients were negative for Legionella on culture and DFA. Low antibody titters to Legionella were observed in 21 patients and these could be attributed to cross reaction with other gram-negative bacteria. All environmental samples and controls tested negative for Legionella. Legionella does not seem to be an important lower respiratory tract pathogen in this part of the country and empirical addition of erythromycin to treatment regimens for pneumonia is not warranted in our setting.

Hepatitis B virus infection in pregnant women and its transmission to infants

HBsAg was screened by Reverse Passive Haemagglutination Test (RPHA) and was confirmed by ELISA test in 157 pregnant females and their newborns. Anti-HBc and IgM anti-HBc was done in these cases by enzyme immuno-assay. The overall prevalence of HBsAg in mothers was 16 out of 157 (10 per cent) and in cord blood of newborns 5 per cent. The transplacental transmission was found in eight of 16 (50 per cent) HBsAg positive mothers. Anti-HBc was present in 12 out of 16 (75 per cent) HBsAg positive mothers and, of these, seven (58 per cent) neonates acquired HBsAg infection. IgM anti-HBc was present in seven out of eight (88 per cent) HBsAg positive neonates, suggesting active in utero infection. Fourteen out of 16 (88 per cent) neonates born to HBsAg positive mothers were alive and healthy, one was stillborn and one had a congenital anomaly.

A preliminary study of fingerprinting of Pseudomonas aeruginosa by whole cell protein analysis by SDS-PAGE

Forty two strains of Pseudomonas aeruginosa isolated from bronchoalveolar lavage fluid from intubated patients admitted to the Intensive care unit in AIIMS between December 1993 to June 1994 were included in the study. After obtaining typical biochemical profile, antimicrobial susceptibility was performed against ceftazidime, amikacin, gentamicin, ampicillin, cefotaxime and ciprofloxacin. Pyocin typing of these 42 strains was performed by scrape and streak method using 22 indicator strains. Forty strains could be typed showing excellent discrimination but on repeated testing the group designation changed indicating that the system had low reproducibility. SDS-PAGE of whole cell protein profile indicated the presence of 45 protein bands of different molecular weights, individual isolates had 37 to 42 protein band ranging in molecular weight from 340 kDa to 14.3 kDa. On the basis of Dice index of similarity the strains could be grouped into 20 types. Since all strains could be typed, the system has adequate typability. Similar results were obtained on repeated testing indicating good reproducibility.

Application of whole cell protein analysis by SDS PAGE to establish the source of Salmonella typhimurium

Salmonella typhimurium isolated from an infant and the powder milk as well as from three different epidemiologically unrelated patients had the same biochemical reactions, antibiogram, serotype and all were non-typable by phage typing. The clonal nature of epidemiologically related isolates was established by SDS PAGE analysis.

Presence of katG gene in resistant Mycobacterium tuberculosis

It has been reported recently that isoniazid resistant strains of Mycobacterium tuberculosis have lost the katG gene which encodes the catalase-peroxidase enzyme. A 35 mer oligonucleotide probe specific for the katG gene of M tuberculosis, 3' end-labelled with digoxigenin, was constructed and hybridised with DNA extracted from 26 clinical isolates of M tuberculosis under high stringency conditions. Twenty two of these isolates were resistant to 0.2 microgram/ml isoniazid and 20 to 1.0 microgram/ml isoniazid. Semiquantitative detection of catalase did not show any discrimination between isoniazid sensitive and resistant strains. The katG gene was present in all clinical strains of M tuberculosis. Therefore, complete deletion of the katG gene does not seem to be the mechanism of isoniazid resistance in M tuberculosis strains isolated from patients in India.

Risk factors for wound infection following elective cholecystectomy

A study of risk factors for wound infection among patients undergoing elective cholecystectomy was undertaken. Over a 2-Year period 177 patients who underwent elective cholecystectomy for symptomatic gall stone disease were randomized into groups, one receiving antibiotics (96 patients) and the other not receiving antibiotics (81 patients). Gall bladder bile and wound swab were cultured to detect bacterial growth. Duration of preoperative hospital stay, type of skin incision and operating time were noted for each patient. Postoperatively wound infection developed in 22/177 (12%) patients. The infection rate was lower in the antibiotic group 3/96 (3%) as compared to the non-antibiotic group 19/81 (23.5%). Wound sepsis occurred in 11/37 (23%) of patients with bactibilia as compared to 11/140 (7.8%) patients with sterile bile. Stepwise logistic regression analysis showed that bactibilia and use of prophylactic antibiotics were the most significant predictors of wound infection in low risk patients undergoing elective cholecystectomy.

Splenic and intestinal lymphocyte proliferation response in mice fed milk or yogurt and challenged with Salmonella typhimurium

Two groups of 4-5 week old DBA/2J Nii mice were put on either a yogurt-based (n = 33) or a milk-based (n = 32) diet for a period of 4 weeks. At the end of the feeding trial one sub group of mice each from the two dietary groups was sacrificed for assessment of immune response. The remaining mice were challenged intragastrically with 2 x 10(10) live Salmonella typhimurium organisms and continued on their respective diets for 8 days after which they were also sacrificed. The immune response was measured by tritiated thymidine uptake by splenic or intestinal lymphocytes in response to the mitogens concanavalin A (Con A), Phytohaemaggutinin (PHA), and Lipopolysaccharide from Escherichia coli (LPS). Serum Immunoglobulin A levels were also estimated. Feed efficiency, measured as weight gain per unit energy intake, was significantly higher for the yogurt diet than for the milk diet. The mitogenic response of splenic and intestinal lymphocytes in the two groups of unchallenged mice was not different. In the Salmonella-challenged mice the stimulation index (SI) of splenic lymphocytes from yogurt-fed mice (mean +/- SD) was significantly higher (P = 0.001) in response to Con A (24.71 +/- 3.40) than that of milk-fed mice (15.85 +/- 2.09). Further, in these mice the SI of intestinal lymphocytes from yogurt-fed mice was higher than that of milk-fed mice in response to Con A (7.35 +/- 0.61 vs 5.65 +/- 0.78, P = 0.016) and LPS (9.04 +/- 0.93 vs 6.15 +/- 1.32, P = 0.016). Serum IgA levels in Salmonella-challenged mice were significantly higher 8 days after the challenge in the yogurt-fed group than in the milk-fed group (P < 0.001). The experiments indicate an improvement in local gastrointestinal as well as systemic immunity on a yogurt diet as compared to a milk diet.

A pilot programme of MRSA surveillance in India. (MRSA Surveillance Study Group)

This surveillance study was conducted simultaneously at three centres across India. A total of 13,610 test samples from various sites were obtained. Microbiological methods employed were similar at the three centres. Identification of S aureus was based on the recognition of the production of coagulase with positive isolates being recorded as S aureus. Both tube coagulase tests and slide coagulase test were performed. Antimicrobial susceptibility testing of the isolated strains of staphylococcus aureus and staphylococcus epidermidis to various antimicrobial discs were carried out according to standardized disk diffusion method recommended by NCCLS. Of the total 739 cultures of S aureus, 235 (32%) were found to be multiply resistant with the individual figures for resistance being 27% (Bombay), 42.5% (Delhi) and 47% (Bangalore). MRSA is emerging to be a significant problem pathogen in the surgical setting with vancomycin probably the only reliable choice for these infections.

A simple method of DNA extraction from Mycobacterium tuberculosis

The application of molecular biology methods has contributed significant insight into the epidemiology of infections caused by Mycobacterium tuberculosis. However, most of the techniques remain out of reach of laboratories in the tropics. We describe here a simple method for extraction of DNA from the pathogen, a first step in the application of molecular biology tools.