Unrelenting Infection of Implanted Prosthetic Hip Joint by Corynebacterium striatum

Non-diphtherial Corynebacterial (NDC) species, while previously considered as culture contaminants, are increasingly being implicated in clinical disease and identified as causes of opportunistic infections. In cases where they grow in pure cultures, isolated from a sterile site or repeated isolations from the same patient, NDC may be labeled as clinically significant. We report here a case of non-healing infection of one of the implanted devices in a case of bilateral total hip replacement, caused by multidrug-resistant Corynebacterium striatum. Adherence to infection prevention strategies is essential for the prevention of prosthetic implant infections.

Multiplex qPCR for differentiation of Mycobacterium avium subspecies paratuberculosis in active and passive infection of goats

Mycobacterium avium paratuberculosis (MAP) is causative agent of Johne's disease (JD) in domestic animals and has broad host range. JD infected animals shed viable MAP in their milk, feces, blood, and tissues which get transmitted to human beings directly or indirectly by consumption of animal products, through contact, animal handling and through contaminated environment, aerosols. In this current study, we developed hydrolysis probe based TaqMan® real-time PCR assay where samples were investigated by targeting IS900 mRNA and ModD gene to differentiate live MAP shedders from inactive/dead MAP bacilli shedding animals. The IS900 mRNA and ModD gene primers were designed using discontiguous unique conserved sequences of IS900 more towards the 3' end and fibronectin attachment protein (FAP) genes, respectively. Two different reporter dyes Cy5 and TexasRed, with compatible quenchers BHQ-1 and BHQ-2, respectively, were used for probe designing of IS900 and ModD genes. Triplex PCR assay was developed by using serially diluted positive MAP culture in log₁₀ dilution and probe and template titration. TaqMan® probe real-time PCR targeting IS900 mRNA and ModD gene detects the MAP infection at early stage with high sensitivity and specificity. The specificity of developed TaqMan probe real-time PCR was found to be high while validated by using Escherichia coli and Staphylococcus aureus in addition to the MAP culture as there is no non-specific signal from other microbes. The sensitivity of developed TaqMan® probe real-time PCR was computed based on copy numbers ranged from 4.14 × 10¹¹ to 4.14 × 10⁴ for IS900 (FAM), 1.27 × 10¹¹ to 1.27 × 10⁴ for IS900 mRNA (Cy5), and 3.68 × 10¹⁰ to 3.68 × 10⁴ for ModD (TexasRed), and lowest limit to detect MAP was 4.14 × 10⁴, 1.27 × 10⁴, and 3.68 × 10⁴ copies for respective genes. This assay would be of great aid to contain the MAP infection in the large herd, where silent shedders spread active infection can be differentiated from passive shedding by non-infected animals. This test would also be equivalent to culture test in terms of specificity and hence can be able to be undertaken in molecular epidemiological studies to represent the actual disease prevalence in the future. KEY POINTS: • Multiplex mRNA-based qPCR was developed to identify the actively infective MAP bacilli from passive ones. • ModD and IS900 used as targets to assess active MAP bacilli in fecal samples of suspected animals. • The LOD was computed using copy numbers with 4.14 × 10⁴ and 3.68 × 10⁴ copies for IS900 and ModD, respectively.

Dynamic CTA-Derived Perfusion Maps Predict Final Infarct Volume: The Simple Perfusion Reconstruction Algorithm

BACKGROUND AND PURPOSE

Infarct core volume measurement using CTP (CT perfusion) is a mainstay paradigm for stroke treatment decision-making. Yet, there are several downfalls with cine CTP technology that can be overcome by adopting the simple perfusion reconstruction algorithm (SPIRAL) derived from multiphase CTA. We compare SPIRAL with CTP parameters for the prediction of 24-hour infarction.

MATERIALS AND METHODS

Seventy-two patients had admission NCCT, multiphase CTA, CTP, and 24-hour DWI. All patients had successful/quality reperfusion. Patient-level and cohort-level receiver operator characteristic curves were generated to determine accuracy. A 10-fold cross-validation was performed on the cohort-level data. Infarct core volume was compared for SPIRAL, CTP-time-to-maximum, and final DWI by Bland-Altman analysis.

RESULTS

When we compared the accuracy in patients with early and late reperfusion for cortical GM and WM, there was no significant difference at the patient level (0.83 versus 0.84, respectively), cohort level (0.82 versus 0.81, respectively), or the cross-validation (0.77 versus 0.74, respectively). In the patient-level receiver operating characteristic analysis, the SPIRAL map had a slightly higher, though nonsignificant (P < .05), average receiver operating characteristic area under the curve (cortical GM/WM, r = 0.82; basal ganglia  = 0.79, respectively) than both the CTP-time-to-maximum (cortical GM/WM = 0.82; basal ganglia = 0.78, respectively) and CTP-CBF (cortical GM/WM = 0.74; basal ganglia = 0.78, respectively) parameter maps. The same relationship was observed at the cohort level. The Bland-Altman plot limits of agreement for SPIRAL and time-to-maximum infarct volume were similar compared with 24-hour DWI.

CONCLUSIONS

We have shown that perfusion maps generated from a temporally sampled helical CTA are an accurate surrogate for infarct core.

In vitro effect of fluoroquinolones against Mycobacterium tuberculosis isolates from Agra & Kanpur region of north India

BACKGROUND & OBJECTIVE

Fluoroquinolones (FQs) are important drugs used for treatment of drug resistant tuberculosis and are also now being considered as first line drugs to shorten the duration of treatment of tuberculosis (TB). In order to find out useful FQs for treatment of tuberculosis, the comparative efficacy of five FQs, namely, ofloxacin (OFL), ciprofloxacin (CIP), sparfloxacin (SPX), gatifloxacin (GAT) and levofloxacin (LEVX) was studied against Mycobacterium tuberculosis (MTB) isolates obtained from both treated and untreated patients from Agra and Kanpur regions of north India.

METHODS

A total of 162 MTB isolates [including 110 MTB isolates obtained from untreated patients (Cat-I) and 52 isolates from treated patients (Cat-II)] were tested for their susceptibilities to FQs using standard minimum inhibitory concentration (MIC) method on Löwenstein-Jensen medium.

RESULTS

Keeping in view the therapeutically achievable drug levels, it was found that in Cat-I 97.2 per cent (107/110) isolates were sensitive to GAT, 89 per cent (98/110) to LEVX at 1 microg/ml whereas 92.7 per cent (102/110) isolates were inhibited by OFL at 2 microg/ml and 73.6 per cent (81/110) to SPX at 0.5 microg/ml. Only 63.6 per cent (70/110) isolates were found to be sensitive to CIP at 2 microg/ml which increased to 89 per cent (98/110) at 4 microg/ml (higher than achievable peak serum level). On the other hand, among 52 isolates for Cat-II, 37 (71.2%) were found to be sensitive to GAT and 33 (63.5%) to LEVX at 1 microg/ml concentration, 28 (53.8%) to SPX at 0.5 microg/ml whereas 33 (63.5%) and 24 (46.2%) isolates were found to be sensitive to OFL and CIP at 2 microg/ml, respectively.

INTERPRETATION & CONCLUSION

It appears that GAT has higher activity against MTB isolates followed by OFL, LEVX and SPX whereas CIP showed the lowest activity. GAT was also found to be the most effective FQ against multi-drug resistant (MDR) isolates both from Cat-I and Cat-II patients. Thus, except CIP, other FQs showed potential to be included in the treatment regimens of tuberculosis including MDR-TB.

Topological potential of zwitterion analogues of cimetidine as H2 receptor antagonists

Topological potential of zwitterionic analogues of cimetidine as H2 receptor antagonists have been investigated using a number of topological indices viz. molecular redundancy index (MRI), first order molecular connectivity index (1chiV) and rooted Wiener (Ww) and rooted Szeged (Szw) indices. The multiple regression analysis have indicated that the H2 receptor antagonist activities (-logKB) can be modelled using indicator parameters. Most significant results were obtained when MRI was coupled with Ww as well as the indicator parameters (Ip1 and Ip2).