New Delhi metallo-ß-lactamase and extended spectrum ß-lactamases co-producing isolates are high in community-acquired urinary infections in Assam as detected by a novel multiplex polymerase chain reaction assay.

BACKGROUND: The ability of microorganisms to evade antibiotic pressure is challenging in healthcare as patients have little or no drug treatment options. Detection of the prevalence of antibacterial resistance pattern helps towards improved antibiotic policy and empirical treatment. OBJECTIVES: We carried out antibiogram profiling and documented the prevalence and co-prevalence of New Delhi metallo-ß-lactamase (NDM) and extended spectrum ß-lactamases (ESBL) encoding genes in urinary Escherichia coli and Klebsiella pneumonia isolates. MATERIALS AND METHODS: Antibiotic susceptibilities were tested for 241 isolates of E. coli and K. pneumoniae from urine samples collected from out- and hospitalised patients. Polymerase chain reaction (PCR) was carried out on isolates tested positive for phenotypic production of metallo-ß-lactamase and ESBL. A multiplex PCR assay was designed to detect the genes. RESULTS: Multiplex PCR assay designed had a limit of detection of 10 3 CFU/mL in vitro. NDM detected was significantly higher among K. pneumoniae compared to E. coli (69.2% vs. 18.2%; P = 0.001). Of 17, 14 NDM positive isolates also harboured ESBL genes. The co-production of CTX-M + TEM + NDM (3/9; 33.3% and 5/8; 62.5%) was most common in K. pneumoniae and E. coli, respectively while CTX-M + TEM + SHV + NDM was found in one isolate. Of the 156 phenotypically ESBL producing isolates, CTX-M, TEM and SHV was detected by PCR in 85, 53 and 24 isolates, respectively. CONCLUSION: NDM and ESBL co-producing isolates were both community (64.7%) and hospital (35.29%) acquired among E. coli. Antibiotic resistance can be effectively evaluated by a cost and time effective molecular method, such as the multiplex PCR used in this study, which complement culture and sensitivity tests.

[Molecular analysis of childhood B-acute lymphoblastic leukemia: Identification and prognosis of rare breakpoints].

Acute lymphoblastic leukaemia (ALL) is the most common subtype of childhood cancer. Detection of a specific gene rearrangement allows the identification of prognostically relevant subgroups in childhood B-ALL. There are four common gene rearrangements which are widely studied to see prognostical values (TEL-AML1, BCR-ABL, E2A-PBX1, MLL-AF4) in childhood B-ALL. In this study we show the prevalence of these common gene rearrangements and also explain the way to identify some rare breakpoints which also occur in these gene rearrangements. 97 samples received for diagnosis from paediatric B-ALL patients were included in this study. Qualitative reverse transcriptase PCR was used for detection of the TEL-AML1-t(12;21), E2A-PBX1-t(1;19), BCR-ABL1-t(9;22) and MLL-AF4 t(4;11) fusion transcripts. Unusually sized amplicons were confirmed by FISH and DNA sequencing to confirm atypical breakpoints. Amongst the paediatric B-ALL samples t(12;21), was detected in (∼20%), t(9;22), was detected in (∼8%), t(1;19) was detected in (∼9%) and t(4;11) was detected in 2 cases. t(12;21) with intron 1of the AML1 gene was detected as the most common gene rearrangement in paediatric ALL, whereas one rare form of the TEL-AML1 breakpoint in which TEL is fused with intron 2 of AML1 was also observed. In the t(9;22) breakpoints e13a2, e14a2 and e1a2 were detected as the common breakpoints. Two atypical and rare breakpoint of t(9;22) were detected namely e6a2 and e13a3 in paediatric ALL. TEL-AML1 was found to be the most common translocation in Paediatric B-ALL. Identification of the rare breakpoints through RT-PCR technique requires designing of PCR in such a way that it can detect these rare breakpoints also.

Multi locus sequence type comparison of invasive and commensal Haemophilus influenzae isolates from Delhi.

Haemophilus influenzae is a major public health concern in the developing world. The most virulent strain is H. influenzae Type b (Hib). Hib also constitutes a major portion of nasopharyngeal commensal flora in otherwise healthy individuals. Through dendogram based on composite gene sequences of seven multi locus sequence type genes, it was observed that invasive and commensal isolates made two completely separate clusters which are indicative of independent evolution of these two groups of H. influenzae in the Indian subcontinent.