Objective:To characterize the bacterial pathogens in patients having gram negative septicaemia. Further,to evaluate the antimicrobial resistance and underlying molecular mechanisms in these strains.Methods:A total number of 70 cases of gram negative sepsis were included in this prospective,open labeled,observational study.Standard methods for isolation and identification of bacteria were used.Antimicrobial susceptibility and ESBL testing was performed by the standard disc diffusion method.PCR amplification was performed to identify blaCTX-M,blaSHVand blaTEM type ESBLs.Conjugation experiments were performed to show resistant marker transfer. Results:The most prevalent isolates Escherichia coli(E.coli) 58.6%,Klebsiella Spp.32.9%and Pseudomonas 8.6%,were resistant to most of the antimicrobials including cefazolin,ceftriaxone, cefuroxime,ampicillin and co-trimoxazole but sensitive to imipenem and meropenem.ESBL and MBL production was seen 7.3%and 12.2%of E.coli isolates respectively.Three isoaltes were found to have blaCTX-M-15 and two of them also showed blaTEM-1 type enxyme.Whereas, none of them showed blaSHV.Conjugation experiments using J-53 cells confirmed these resistant markers as plasmid mediated.Conclusions:This work highlights the molecular epidemiology of escalating antimicrobial resistance and likely switch over of blaCTX-M-15 type extended spectrum beta-lactamases by blaTEM type ESBLs in India.Further,the antimicrobial resistance by horizontal gene transfer was predominant among Enterobacteraceae in the community setting.
Shahzad F HaqueSaeedut-Z AliMohammed TPAsad U Khan
Objective:To look for secondary bacterial infections in bronchogenic carcinoma(BCA) with resistant organisms harboring bla genes considering the paucity of relevant studies.Methods: A total of 137 confirmed cases of BCA and 34 healthy volunteers were studied for the occurrence and prevalence of blaCTX-M and and blaAmpC harboring-enterobacteriaceae.A subset of these patients(n=69) was previously reported for the secondary infection with the Aspergillus species. Bronchoalveolar lavages(BAL) were subjected for bacterial and fungal cultures and the bacterial isolates were screened by multiplex PCRs for the presence of blaCTX-M and blaAmpC.The isolates were also screened for the association of insertion sequence(IS26) by PCR and characterized by RAPD for any clonal relatedness.Results:A total of 143 bacterial isolates were obtained from 137 BAL specimens of BC,patients.The Enterobacteriaceae-isolates were multidrug-resistant showing concomitant resistance to fluoroquinolones and aminoglycosides.Both blaCTX-M and blaAmpC of CIT family were detected in 77.4%and 27.4%isolates,respectively.Sequencing revealed the presence of blaCTX-M-15 and blaCMY-6.Twenty one percent of the isolates were simultaneously harboring blaampC and blaCTX-M-15.IS26 PCR and RAPD typing revealed the presence of diverse bacterial population but no predominant clone was identified.The present study also suggests strong association of aspergillosis with lung cancer and further strengthens the potential use of non-validated serological tests suggested earlier.Conclusions:We emphasize that all patients of bronchogenic carcinoma should also be screened for secondary bacterial infections,along with secondary fungal infections,so as to introduce early and specific antimicrobial therapy and to prevent unwanted deaths.