Differential expression of virulence genes and role of gyrA mutations in quinolone resistant and susceptible strains of Salmonella Weltevreden and Newport isolated from seafood.

AIMS: To investigate the differential expression of virulence genes and role of gyrA mutations in quinolone resistant and susceptible strains of Salmonella isolated from seafood. METHODS AND RESULTS: Forty Salmonella isolates from seafood were tested for antibiotic sensitivity. Minimal inhibitory concentration (MIC) was determined and two nalidixic acid-resistant isolates, viz Salmonella Weltevreden (SW9) and Salmonella Newport (SN36) were selected for identifying the mechanism of resistance. SW9 showed mutation in the gyrA gene at codon 83 (Ser to Tyr) while SN36 presented at codon 87 (Asp to Asn). Experimental induction of resistance to a sensitive Salm. Newport (SN71) showed point mutation at codon 87 (Asp to Gly) in the gyrA gene, and was designated SN71R. All the isolates resistant to nalidixic acid had a single mutation at different positions in the gyrA gene. However, induction of resistance to a sensitive Salm. Weltevreden (SW30) was exceptional in that it did not show any mutation in the gyrA region. Use of Phe-Arg-ß-naphthylamide (PAßN) also could not reduce MIC below the Clinical and Laboratory Standards Institute guidelines revealing the absence of efflux mediated resistance. Thus, the resistance mechanism in SW30R is unknown. The growth rate of quinolone resistant isolates was slower than the susceptible ones. The resistant isolates showed decreased epithelial cell invasion and intracellular replication. The mRNA expression levels of some of the genes were significantly (P < 0·005) reduced in SN71R compared to the sensitive strain (SN71). CONCLUSIONS: Nalidixic acid-resistant Salmonella strains are associated with lower virulence and pathogenicity than the sensitive strains. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provided valuable information on the difference in the growth, cytotoxicity, infectivity and expression of virulence genes in resistant and susceptible strains. Furthermore, the gyrA mutation was shown to be the main mechanism of quinolone resistance in Salmonella other than the overexpression of efflux pumps or the presence of plasmid mediated quinolone resistance genes.

Presence of T3SS2ß genes in trh⁺ Vibrio parahaemolyticus isolated from seafood harvested along Mangalore coast, India.

UNLABELLED: Vibrio parahaemolyticus is a seafood-borne pathogen autochthonous to the marine and estuarine ecosystem, responsible for gastroenteritis when contaminated raw seafood is consumed. The pathogenicity has been associated with thermostable direct haemolysin (TDH) and TDH-related haemolysin (TRH). Of late, the presence of T3SS2α and T3SS2ß gene clusters has been well documented in clinical isolates of Vibrio parahaemolyticus and known to play an essential role in pathogenesis. However, reports on the presence of T3SSß genes in V. parahaemolyticus isolated from the seafood and/or environmental samples are scanty. In this study, we have identified and analysed the distribution of the T3SS2ß genes in V. parahaemolyticus isolated from seafood harvested along southwest coast of India. Results showed that T3SS2ß genes are solely associated with trh⁺ and tdh⁺ /trh⁺ strains of V. parahaemolyticus. Reverse transcriptase PCR (RT-PCR) showed that the T3SS2ß genes identified in trh⁺ V. parahaemolyticus were transcriptionally active. To our knowledge, this study appears to be the first description on the presence of T3SS2ß-positive V. parahaemolyticus isolated from seafood in India. The study of T3SS2 along with other virulence factors will help in better understanding of the risk of seafood-borne illness due to V. parahaemolyticus. SIGNIFICANCE AND IMPACT OF THE STUDY: T3SSs (α or ß) are the important virulence factors of Vibrio parahaemolyticus that contribute to their pathogenicity in humans. This study demonstrated the presence of T3SS2ß genes in V. parahaemolyticus isolated from the seafood harvested along Mangalore coast. RT-PCR showed that the T3SS2ß genes identified in seafood isolates of V. parahaemolyticus were found to be functional. To the best of our knowledge, this is the first description of T3SS2ß genes in trh⁺ V. parahaemolyticus isolated from seafood in India. The presence of T3SS2 along with other virulence factors such as TDH and/or TRH highlights a potential health risk for seafood consumers.

Detection of class 1 integrons in Salmonella Weltevreden and silent antibiotic resistance genes in some seafood-associated nontyphoidal isolates of Salmonella in south-west coast of India.

AIMS: To study the antibiogram of 40 seafood isolates of Salmonella and use of PCR to detect the presence of integrons and genes coding for antibiotic resistance. METHODS AND RESULTS: In this study, 40 isolates of Salmonella were used for antibiogram analysis. The multidrug-resistant isolates were analyzed for the presence of integron using integron-specific primers. Twenty-five percentage of the isolates were multidrug resistant while 67·50% were resistant to at least two antibiotics. Antibiotic resistance genes catA1 and tetA were present in 57·52 and 60%, respectively. Although widespread presence of genes was observed, only 26·08% of the catA1-carrying isolates exhibited phenotypic resistance against the respective antibiotic. Integrons present in representative isolates of Salmonella Weltevreden and Salmonella Newport were sequenced. The former contained class 1 integron with a single gene dfrA7 in the integron cassette and an adjacent dihydropteroate synthetase gene along with the usual quaternary ammonium compound resistance gene, while the later contained class 1 integron with dhfrA1, OrfC, in the integron cassette and an adjacent dihydropteroate synthetase gene along with the usual quaternary ammonium compound resistance gene. CONCLUSIONS: This study demonstrates the presence of silent antibiotic resistance genes and class I integrons in seafood-associated Salmonella strains. The study also demonstrates the first report of class I integron in Salm. Weltevreden. Detection of catA1 genes in phenotypically sensitive bacteria suggests that these could be reservoirs in the environment. SIGNIFICANCE AND IMPACT OF THE STUDY: The manuscript provides novel results describing the existence of a high rate of antibiotic resistance in the Salmonella populations prevailing in environmental sources as well as an absence of correspondence between the presence of antibiotic resistance genes, and the exhibition of a the corresponding phenotypic trait of resistance against the respective antibiotic compound was observed. In addition, the manuscript reports the presence of the class I integron in Salm. Weltevreden.

Arrhythmia detection and classification using morphological and dynamic features of ECG signals.

Computer-assisted cardiac arrhythmia detection and classification can play a significant role in the management of cardiac disorders. In this paper, we propose a new approach for arrhythmia classification based on a combination of morphological and dynamic features. Wavelet Transform (WT) and Independent Component Analysis (ICA) are applied separately to each heartbeat to extract corresponding coefficients, which are categorized as 'morphological' features. In addition, RR interval information is also obtained characterizing the 'rhythm' around the corresponding heartbeat providing 'dynamic' features. These two different types of features are then concatenated and Support Vector Machine (SVM) is utilized for the classification of heartbeats into 15 classes. The procedure is applied to the data from two ECG leads independently and the two results are fused for the final decision. Compare the two classification results and the classification result is kept if the two are identical or the one with greater classification confidence is picked up if the two are inconsistent. The proposed method was tested over the entire MIT-BIH Arrhythmias Database [1] and it yields an overall accuracy of 99.66% on 85945 heartbeats, better than any other published results.

Expanded safety study of Praneem polyherbal vaginal tablet among HIV-uninfected women in Pune, India: a phase II clinical trial report.

BACKGROUND: Praneem, a candidate vaginal microbicide with reported anti-HIV and contraceptive properties was evaluated for its long-term safety through a double-blind, placebo-controlled, randomised phase II trial. METHODOLOGY: 142 women were screened and 100 HIV-uninfected, eligible women were enrolled, after obtaining written informed consents. Of these, 50 were randomly assigned to the study product arm and 50 to the placebo arm. Participants were requested to use the study product at least half an hour before each sexual act for 6 months. RESULTS: Participants in both treatment groups contributed 601 person-months of follow-up and 95% of the participants completed the last follow-up. Although transient genital discomfort was the main reported adverse experience, none of the study participants discontinued product use. Most of the adverse events were mild and there were no serious adverse events related to study product use and no HIV seroconversions. DISCUSSION: Praneem polyherbal tablet was safe for vaginal use up to 6 months with each act of sex among low-risk women. In light of the failure of Nonoxynol-9, cellulose sulphate and Carraguard in preventing HIV infections among women, additional preclinical evaluations should be undertaken urgently before moving into effectiveness studies.

Psychological Correlates of Outcome after Coronary Artery Bypass Graft.

BACKGROUND: Psychological effects of Coronary Artery Bypass graft (CABG) have been of interest all over the world but there is a paucity of Indian work. METHODS: 30 patients undergoing CABG at a service hospital were included. All patients filled a specially designed proforma. Mini Mental Status Examination, Hospital anxiety and depression scale, Coronary scale, Seattle angina questionnaire and Euro-QOL 5D were performed before and seven days after CABG. RESULTS: 43.3% had significant anxiety and 30% had significant depression before CABG. Following CABG, 36.67% of the patients had significant anxiety while 40% had significant depression. On the Seattle angina questionnaire, physical limitation reduced from 71.6 ± 7.9 to 53.1 ± 14.6. There was significant improvement in treatment satisfaction from 37.8 ± 6.1 to 59.4 ± 4.2 following CABG. On th euro quality of life scale (EQ5D) health status improved from 38.17 ± 9.51 before CABG to 68.5 ± 5.28 after CABG. CONCLUSION: There is a significant incidence of anxiety and depression in patients undergoing CABG, both before and after surgery.

Modelling epidemiology of leprosy.

A simulation model for leprosy transmission and control has been developed with specific objectives. Several sensitivity experiments have been carried out by altering the various inputs based on empirical data combined with intelligent guessing. The outputs generated through these exercises were on the expected lines. While incremental exercises would improve the model, it can be used even at the existing stage as a tool for programme managers.

Optimal tradeoff circular harmonic function correlation filter methods providing controlled in-plane rotation response.

Correlation methods are becoming increasingly attractive tools for image recognition and location. This renewed interest in correlation methods is spurred by the availability of high-speed image processors and the emergence of correlation filter designs that can optimize relevant figures of merit. In this paper, a new correlation filter design method is presented that allows one to optimally tradeoff among potentially conflicting correlation output performance criteria while achieving desired correlation peak value behavior in response to in-plane rotation of input images. Such controlled in-plane rotation response is useful in image analysis and pattern recognition applications where the sensor follows a pre-arranged trajectory while imaging an object. Since this new correlation filter design is based on circular harmonic function (CHF) theory, we refer to the resulting filters as optimal tradeoff circular harmonic function (OTCHF) filters. Underlying theory, OTCHF filter design method, and illustrative numerical results are presented.

Stochastic compartmental models with Prendville growth mechanisms.

We consider a stochastic compartmental model in which cells reproduce in accordance with a regulated birth and death process. We find expressions for the mean vector and covariance matrix for the number of cells in these compartments. We obtain the asymptotic behavior of the mean vector in the general case and explicit expressions for two compartmental and mammillary systems.

Efficacy and limitations of QBC acridine orange staining as a routine diagnostic technique for malaria in developing countries.

The recently developed QBC technique has been reported to be rapid, sensitive and specific for the detection of malaria infection. We evaluated this technique in comparison with thin and thick Giemsa stained blood films for the diagnosis of malaria in acute fever and PUO cases. The technique was slightly more sensitive than thin blood film but equal to thick blood film examination. Identification of species of malaria posed some difficulties. Due to its high cost and requirement for a fluorescent microscope this technique, in spite of its speed and sensitivity, may not have the potential to be a substitute for the conventional blood film examination for the diagnosis of malaria, especially in developing countries.