Loop-mediated isothermal amplification assay for the diagnosis of retinitis caused by herpes simplex virus-1

A loop-mediated isothermal amplification (LAMP) assay was developed for the detection of herpes simplex virus 1 (HSV-1). The specificity of the assay was tested using DNA extracted from HSV-1-infected rabbit corneal epithelium cultures, HSV-2 grown on Vero cell line, cytomegalovirus (CMV) (AD-169), varicella zoster virus (VZV) (Oka-vaccine), adenovirus, Aspergillus flavus and Staphylococcus aureus. The specificity of LAMP was confirmed by bidirectional sequencing of the amplicons. The sensitivity of the LAMP assay was tested using different concentrations of HSV-1 DNA. To evaluate the application of the LAMP assay in clinical diagnosis, we tested vitreous samples from 20 patients with suspected viral retinitis using LAMP and real-time PCR for HSV-1. The LAMP primers amplified only HSV-1 DNA; no LAMP products were detected with the DNAs of HSV-2, CMV, VZV, adenovirus A. flavus and S. aureus. The sequences of the positive HSV-1 LAMP products perfectly (99–100%) matched the HSV-1 sequences deposited in the GenBank database. LAMP is as sensitive as real-time PCR, with the lowest detection limit being 10 copies/μL of HSV-1 DNA. Of the 20 patients with suspected viral retinitis, four tested positive for HSV-1 using real- time PCR and LAMP. A 100% concordance was observed across the two methods. The LAMP assay is a rapid, highly specific and sensitive method for the diagnosis of retinitis caused by HSV-1.

Simple and economical method for speciation and resistotyping of clinically significant coagulase negative staphylococci

An attempt was made to speciate 102 clinically significant isolates of coagulase negative staphylococci (CoNS) by a practical scheme adapted from various references. This scheme utilizes slide and tube coagulase test, urease test ornithine decarboxylase, novobiocin susceptibility and aerobic acid from mannose for assigning species group. Inclusion of one or two additional tests in a species group could identify the isolates to species level. Ninety eight (97%) isolates were conveniently identified as S. epidermidis (41%), S. saprophyticus (16.6%), S. haemolyticus (14.7%), S. hominis (14.7%), S. lugdunensis (4.9%), S. schleiferi (1.9%) and S. capitis (1.9%). Only four isolates were not identified to the species level, two of which were probably S. capitis subspecies ureolyticus / S. warneri / S. simulans . Antibiotic susceptibility testing showed maximum resistance to ampicillin (89%) followed by cefotaxime (59%) with no resistance to vancomycin. The increasing recognition of pathogenic potential of CoNS and emergence of drug resistance amongst them denotes the need to adopt simple laboratory procedures to identify and understand the diversity of staphylococci isolated from clinical material.

Superior ex vivo cord blood expansion following co-culture with bone marrow-derived mesenchymal stem cells

One factor limiting the therapeutic efficacy of cord blood (CB) hematopoietic progenitor cell (HPC) transplantation is the low cell dose of the graft. This is associated with an increased incidence of delayed or failed engraftment. Cell dose can be increased and the efficacy of CB transplantation potentially improved, by ex vivo CB expansion before transplantation. Two ex vivo CB expansion techniques were compared: (1) CD133+ selection followed by ex vivo liquid culture and (2) co-culture of unmanipulated CB with bone-marrow-derived mesenchymal stem cells (MSCs). Ex vivo culture was performed in medium supplemented with granulocyte colony-stimulating factor, stem cell factor and either thrombopoietin or megakaryocyte growth and differentiation factor. Expansion was followed by measuring total nucleated cell (TNC), CD133+ and CD34+ cell, colony-forming unit and cobblestone area-forming cell output. When compared to liquid culture, CB-MSC co-culture (i) required less cell manipulation resulting in less initial HPC loss and (ii) markedly improved TNC and HPC output. CB-MSC co-culture therefore holds promise for improving engraftment kinetics in CB transplant recipients.

Effect of topical calcipotriol, betamethasone dipropionate and their combination in the treatment of localized vitiligo

BACKGROUND

Treatment of vitiligo is a challenge. Steroids are known to be effective but are associated with serious adverse effects. Many uncontrolled studies have shown calcipotriol to be a promising therapeutic modality in vitiligo.

OBJECTIVE

To conduct a randomized trial to evaluate the effect of topical calcipotriol ointment (0.005%) and betamethasone dipropionate (0.05%) cream, given alone or in combination, in treatment of localized vitiligo.

METHODS

Forty-nine patients with vitiligo affecting 5% of their skin were recruited. Patients were randomized into three groups. Group I patients were treated with betamethasone dipropionate (0.05%) cream twice daily. Group II patients were treated with calcipotriol ointment (0.005%) twice daily, and group III with betamethasone dipropionate (0.05%) in the morning and calcipotriol (0.005%) in the evening.

RESULTS

Forty-five patients completed the study period of 3 months with 15 patients in each group. No patient achieved excellent (> 75%) pigmentation. Marked (50% to 75%) repigmentation was observed in 2 (13.3%), 1 (6.7%) and 4 (26.7%) patients in groups I, II and III, respectively. Moderate (25-50%) repigmentation was observed in 7 (46.7%), 5 (33.3%) and 7 (46.7%) patients in groups I, II and III, respectively. Patients with < 25% pigmentation were termed as minimal pigmentation or no response. The mean time for initial pigmentation to appear was 9.04 +/- 2.0 weeks in group I, 10.18 +/- 1.6 weeks in group II and 5.17 +/- 2.4 weeks in group III (P < 0.01). The acquired pigmentation in the lesions was more stable in group III as compared with patients in groups II and I (P < 0.01). Side-effects in the form of atrophy and lesional burning sensations were more common in group I when compared with groups II and III (P < 0.05).

CONCLUSION

Combined therapy appeared to give a significantly faster onset of repigmentation along with better stability of the achieved pigmentation and with lesser number of side-effects.

Single-Dose Fluconazole versus Itraconazole in Pityriasis versicolor

BACKGROUND

The new antifungal triazoles itraconazole and fluconazole have revolutionized the treatment of pityriasis versicolor. Both drugs have shown promising results in different dose schedules.

OBJECTIVE

To compare the efficacy and safety of single oral dose treatment with fluconazole versus itraconazole in patients with pityriasis versicolor.

METHODS

A total of 40 patients with pityriasis versicolor were allocated randomly to group A and group B. A single dose of fluconazole (400 mg) or itraconazole (400 mg) was given orally to group A or group B patients, respectively. Patients were assessed mycologically by KOH and culture. Culture was done from lesional and perilesional skin to quantify growth and to observe the effect of these drugs and the persistence/reappearance of the fungus in relation to relapse at 2 and 8 weeks. Relapse was defined as reappearance or worsening of clinical signs and symptoms or positive KOH/culture after initial improvement.

RESULTS

Thirteen (65%) patients in the fluconazole group and 4 (20%) patients in the itraconazole group became culture negative at the end of 8 weeks. Relapse was found to be higher in the itraconazole group compared to the fluconazole group (60 vs. 35%). A direct correlation was found between the relapse rate and positivity of perilesional skin for Malassezia furfur.

CONCLUSION

In the same dosing, fluconazole was found to be more effective than itraconazole; however, both drugs were found to be safe.

Leprosy and herpes zoster; an association or dissociation?

Nerve involvement is common to the pathogenesis of both leprosy and herpes zoster. We report two cases of borderline leprosy in which the skin lesions characteristically spared the healed zoster scar. Possible mechanisms and relationship are discussed.

Changing trends in bacteriology of burns in the burns unit, Delhi, India

A retrospective study of bacterial isolates from the wounds of patients admitted to burns unit, was undertaken at Guru Tegh Bahadur Hospital, University College of Medical Sciences, Delhi, India, over a period of 5 years between July 1997 and April 2002. The study compared the results obtained with the previous 5 years data (June 1993-June 1997) from the same unit to determine the changing patterns and emerging trends of bacterial isolates and their antimicrobial susceptibilities. Pseudomonas species (31%) and Staphylococcus aureus (22%) were the most common pathogens followed by Klebsiella species (19%). Multi-drug resistant (MDR) Acinetobacter species (9%) have emerged as an important nosocomial pathogen in our burn unit. Most of the gram-negative isolates obtained were found to be multi-drug resistant and 61% of the tested isolates were extended spectrum beta-lactamase (ESBL) producers. Concomitant resistance to penicillin and aminoglycosides was observed in 61% of Enterococcus fecalis isolates. When compared with the results of previous 5 years (June 1993-June 1997) Pseudomonas spp. was still the commonest pathogen in the burns unit. However, isolation of this organism and other gram-negative organisms has decreased in comparison to previous years. The incidence of antimicrobial resistance has markedly increased over the past years resulting in limitation of therapeutic options.