Comparative study of efficacy, rapidity of detection, and cost-effectiveness of potassium hydroxide, calcofluor white, and Chicago sky blue stains in the diagnosis of dermatophytoses.

BACKGROUND: The diagnosis of superficial mycosis such as dermatophytosis is often done clinically. However, in difficult cases, a rapid test with high sensitivity and specificity helps in the immediate confirmation and administration of treatment. METHODS: The efficacy, rapidity of detection, and cost-effectiveness of KOH preparation, calcofluor white (CW) stain, and Chicago sky blue (CSB) stain in the identification of fungal elements were assessed in patients with dermatophytoses attending the dermatology clinic of a tertiary care hospital. All three tests were performed on each sample collected from 73 patients according to standard procedure. The slides were examined after 5 and 30 minutes in × 10 and × 40 magnifications. The sensitivity and specificity of CW and CSB at 5 and 30 minutes were calculated using KOH preparation as the standard test. RESULTS: CSB stain showed highest positivity (94.5%) within 5 minutes when compared to KOH (75.3%) and CW (83.5%). After 30 minutes, positivity increased in KOH (84.9%) and CW stains (89%), but it remained the same in CSB stain. Both CW and CSB stains when compared to 10% KOH are equally sensitive (100%), but CW was more specific (72.7%), particularly at 30 minutes. When cost of performing tests on 100 specimens is considered, KOH, CW, and CSB stains cost Rs 5, 100, and 15, respectively. CONCLUSION: CSB stain is a better stain for rapid diagnosis of dermatophytoses because of ease of performance, rapidity of detection, better appreciation of morphology of fungal elements, and cost effectiveness.

Methicillin Resistant Staphylococcus aureus Carriage, Antibiotic Resistance and Molecular Pathogenicity among Healthy Individuals Exposed and Not Exposed to Hospital Environment.

BACKGROUND: Healthcare workers as well as healthy community-dwelling individuals may be colonised by methicillin-resistant Staphylococcus aureus (MRSA). Healthcare workers who carry MRSA may transmit it to patients, causing various nosocomial infections. Literature shows that the differences between MRSA isolated from healthcare settings and from community settings, with regard to multi-drug resistance (traditionally exhibited by the former) and possession of pvl genes (traditionally exhibited by the latter), is diminishing due to a large community reservoir and increasing influx of community harboured strains into the hospital. However, there is no literature on the current scenario in India. AIMS AND OBJECTIVES: This study examines the influence of exposure to hospital environment on MRSA carriage, antimicrobial resistance patterns of MRSA, and the presence of genes encoding five extracellular pathogenicity determinants (pvl, sea, seb, tsst-1 and hly a). MATERIALS AND METHODS: Nasal, throat and palmar swabs were collected from 119 nursing students of the age group 18-23 years (exposed group) and 100 age matched pharmacy students (non-exposed group). S. aureus was identified and antibiogram obtained as per Clinical and Laboratory Standards Institute (CLSI) guidelines. MRSA was detected by cefoxitin disc diffusion test and by growth on oxacillin screen agar as per CLSI guidelines. Conventional PCR was performed for mecA, pvl, sea, seb, tsst-1 and hly a. RESULTS: The differences in carrier rates, antibiotic resistance patterns and expression of extracellular pathogenicity determinants between MRSA isolates from the two study groups were not significant, and pvl was found in all the MRSA isolates. CONCLUSION: The nursing students carried MRSA strains similar to those carried by the non-exposed group. Our results suggest that healthcare workers could act as a link and transmit MRSA acquired from the community to patients.

Phenotypic and Genotypic Methods for Detection of Extended Spectrum ß Lactamase Producing Escherichia coli and Klebsiella pneumoniae Isolated from Ventilator Associated Pneumonia.

BACKGROUND: Ventilator Associated Pneumonia (VAP) is one of the common nosocomial infections associated with high morbidity due to multidrug resistant pathogens. Rapid spread of resistance to broad spectrum beta-lactams in pathogenic strains causes antibiotics ineffectiveness and increased severity of illness. The CTX-M is the most dominant Extended Spectrum ß Lactamase (ESBL) among Enterobacteriaceae in many regions of the world. The aim of the study was to identify the occurrence of ESBL and detect the genes responsible for ESBL production by conventional Polymerase Chain Reaction (PCR) method. METHODS: This prospective study included patients, clinically diagnosed as VAP. Endotracheal aspirates (EA) were collected and cultured by quantitative method. The bacterial isolates were identified as per standard methods. Isolates resistant to 3(rd) generation cephalosporins were screened for ESBL production by disk approximation method and combination disc diffusion method. Isolates confirmed as ESBL producers were subjected to genotyping by conventional PCR. STATISTICAL ANALYSIS: Statistical analysis was done by using MS Excel sheet. Descriptive statistics like percentage was done in the study. RESULTS: Among the isolates from 428 patients who developed VAP, 144 isolates belonged to the Enterobacteriaceae family (Klebsiella pneumoniae 87 and Escherichia coli 57). A total of 66 isolates (28 Klebsiella pneumoniae and 38 Escherichia coli) were confirmed as ESBL producer by disc approximation method and 63 isolates by double disc combination method. In the present study by conventional PCR bla CTX-M was the common gene in 48.5% strains followed by 22.22% bla SHV and 14.81% bla TEM. CONCLUSION: The genotypic methods using specific PCR amplification of resistance genes seems to have 100% specificity and sensitivity in detection of ESBL when compared to phenotypic methods which lacks the constant sensitivity.

Inducible clindamycin resistance in Staphylococcus aureus isolated from nursing and pharmacy students.

AIMS: Emergence of resistant isolates of Staphylococcus aureus (S. aureus) has resulted in failure of clindamycin therapy. The prevalence of inducible clindamycin resistance in S. aureus isolated from nursing students and pharmacy students (representing carriers exposed and not exposed to hospital environment respectively) was evaluated. MATERIALS AND METHODS: Nasal, throat, and palmar swabs were collected from 119 nursing students and 100 pharmacy students. S. aureus was identified and antibiogram obtained by Clinical and Laboratory Standards Institute guidelines. Inducible clindamycin resistance was detected by the D-test. RESULTS: 36 and 34 individuals in the exposed and non-exposed groups respectively were carriers of S. aureus. 16.7% and 5.9% isolates showed inducible clindamycin resistance in exposed and non-exposed groups, respectively. The percentage of inducible clindamycin resistance was higher among methicillin-resistant S. aureus (MRSA) (27.8%) compared to methicillin-sensitive S. aureus (5.8%). CONCLUSION: S. aureus isolates resistant to ß-lactams can also show inducible clindamycin resistance. Exposure to hospital environment was not found to be a risk factor for carriage of S. aureus with MLSBi phenotype.