Pulmonary tuberculosis still remains a major communicable disease worldwide. In 2013, 9 million people developed TB and 1.5 million people died from the disease. India constitutes 24% of the total TB burden. Early detection of TB cases is the key to successful treatment and reduction of disease transmission. Xpert MTB/RIF, an automated cartridge-based molecular technique detects Mycobacterium tuberculosis and rifampicin resistance within two hours has been endorsed by WHO for rapid diagnosis of TB. Our study is the first study from India with a large sample size to evaluate the performance of Xpert MTB/RIF assay in PTB samples. The test showed an overall sensitivity and specificity of 95.7% (430/449) and 99.3% (984/990) respectively. In smear negative-culture positive cases, the test had a sensitivity of 77.7%. The sensitivity and specificity for detecting rifampicin resistance was 94.5% and 97.7% respectively with respect to culture as reference standard. However, after resolving the discrepant samples with gene sequencing, the sensitivity and specificity rose to 99.0% and 99.3% respectively. Hence, while solid culture still forms the foundation of TB diagnosis, Xpert MTB/RIF proposes to be a strong first line diagnostic tool for pulmonary TB cases.

BackgroundThe objectives of the study were to compare the performance of line probe assay (GenoType MTBDRplus) with solid culture method for an early diagnosis of multidrug resistant tuberculosis (MDR-TB), and to study the mutation patterns associated with rpoB, katG and inhA genes at a tertiary care centre in north India.MethodsIn this cross-sectional study, 269 previously treated sputum-smear acid-fast bacilli (AFB) positive MDR-TB suspects were enrolled from January to September 2012 at the All India Institute of Medical Sciences hospital, New Delhi. Line probe assay (LPA) was performed directly on the sputum specimens and the results were compared with that of conventional drug susceptibility testing (DST) on solid media [Lowenstein Jensen (LJ) method].ResultsDST results by LPA and LJ methods were compared in 242 MDR-TB suspects. The LPA detected rifampicin (RIF) resistance in 70 of 71 cases, isoniazid (INH) resistance in 86 of 93 cases, and MDR-TB in 66 of 68 cases as compared to the conventional method. Overall (rifampicin, isoniazid and MDR-TB) concordance of the LPA with the conventional DST was 96%. Sensitivity and specificity were 98% and 99% respectively for detection of RIF resistance; 92% and 99% respectively for detection of INH resistance; 97% and 100% respectively for detection of MDR-TB. Frequencies of katG gene, inhA gene and combined katG and inhA gene mutations conferring all INH resistance were 72/87 (83%), 10/87 (11%) and 5/87 (6%) respectively. The turnaround time of the LPA test was 48 hours.ConclusionThe LPA test provides an early diagnosis of monoresistance to isoniazid and rifampicin and is highly sensitive and specific for an early diagnosis of MDR-TB. Based on these findings, it is concluded that the LPA test can be useful in early diagnosis of drug resistant TB in high TB burden countries.

The effectiveness of the metal oxide nanoparticles viz. CuO and Fe 2 O 3 as antibacterial agents against multidrug resistant biofilm forming bacteria was evaluated. CuO nanoparticles were also experimented for antibiofilm and time kill assay. The CuO displayed maximum antibacterial activity with zone of inhibition of (22 ± 1) mm against methicillin resistant Staphylococcus aureus (MRSA) followed by Escherichia coli (18 ± 1) mm. The Fe 2 O 3 showed the zone of inhibition against MRSA of (14 ± 1) mm followed by E. coli (12 ± 1) mm. CuO proved to be more toxic than Fe 2 O 3 nanoparticles showing significantly high antibacterial activity and found to possess dose dependent antibiofilm properties.Biofilm can be defined as the microbial-derived sessile communities characterized by the cells that remain attached to any surface. Quorum sensing among the biofilm forming organisms plays significant role in the formation of biofilm [4,6]. Urinary catheters when inserted into the human body parts, may readily acquire biofilm. Eradication of the biofilm is very hard and cause many chronic infections. Recent research work reveals that use of quorum sensing inhibitors could be useful for restricting biofilm formation [3,5]. Nanoparticles have good antibacterial activity and they could be used as an effective bactericidal agent [8,10,11]. Considering the above facts, experiment was conducted for detection of biofilm producing uropathogens and antibacterial/antibiofilm activity of iron oxide and copper oxide nanoparticles against multidrug resistant biofilm forming uropathogens was investigated.A total of 50 samples and 213 isolates were screened for the biofilm production. All the clinical samples were collected from hospitalized female patients with urinary catheter inserted for more than 2 days from government hospitals in Sonitpur (Tezpur) (Lat. 26.63°N Long. 92.8°E) and Dibrugarh (Lat. 27.48°N Long. 95°E) districts of Assam, India.The biofilm formation was analyzed by different standard methods [9]. Table 1 represented biofilm formation by uropathogens isolated from urine of normal and hospitalised females with urinary catheter inserted. Among 168 clinical samples maximum 88 isolates (52.4 %) of uropathogens were detected as biofilm former in Microtitre plate method. Among different biofilm formers Escherichia coli detected as maximum biofilm producer with 24 isolates (80 %) followed by Proteus mirabilis, 16 isolates (72.73 %); Staphylococcus aureus, 16 isolates (57.1 %); Enterococcus faecalis, 14 isolates (53.8 %); Pseudomonas species 14 isolates (43.8 %) and Staphylococcus epidermidis 4 isolates (40 %).Antibiotic resistance of different kinds of uropathogens was studied by Kirby-Bauer disc diffusion method on MHA plates, which revealed that resistance was higher in biofilm formers than in non-biofilm formers. Three antibiotics namely penicillin, ampicillin and piperacillin were found to be resistant equally in both biofilm formers (100 %) and non-biofilm formers (100 %). Among Grampositive biofilm formers, oxacil...

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Foley's catheters were coated with Silver (Ag), plasma polymerized aniline (PPAni) and Ag-PPAni composite by plasma based deposition processes which were characterized by XRD, EDX, SEM, and FT-IR spectroscopy and bioassays were performed to validate their efficacies to kill planktonic cells as well as to remove biofilm. The analyses confirmed the formation of Ag nanoparticles (AgNPs), PPAni and Ag-PPAni composite and also corroborated their successful deposition over the catheters. Antibacterial assays showed that coated catheters were capable of killing planktonic cells of most commonly encountered uropathogens and equally capable of eradicating biofilm formation by the uropathogens as evident from the reduced cfu/ml. UV-vis spectroscopy results showed that the nanoparticle coated catheters were capable of gradual release of AgNPs, killing all planktonic cells in solution over the time. Foley's catheters coated with AgNPs and their composites by one step plasma process were non-toxic devices capable of killing planktonic cells and proficient in eradicating biofilm formation which could be used to cutback the likelihood of the catheter related complications.

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