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Introduction: Bacterial resistance to antibiotics has beena recognized reality almost since the dawn of the antibioticera, but only within the past twenty years has the emergenceof dangerous, resistant strains occurred with a disturbingregularity. Objective: Prevalence of carbapenem resistantGram negative organisms in a tertiary care hospital of NorthIndia.Material and methods: Various clinical specimens collectedfrom indoor and OPD were processed. Identification of theGram negative organisms and carbapenem resistance wasdone by standard bacteriological techniques. All isolates weredetected for carbapenemase production by Carba NP test.Results: Out of 1670 samples, 935 (55.99%) were found to beculture positive of which 485 (51.87%) were Gram negativebacteria. The prevalence of carbapenemase producing Gramnegative bacteria was 58 (11.96%).Conclusion: Determing carbapenem resistance pattern andconfirmation of carbapenemase production can improviseupon the usage of antimicrobials which will further help inreducing the burden of antimicrobial resistance.
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Background & objectives: The growing incidence and the wide diversity of carbapenemase-producing bacterial strains is a major concern as only a few antimicrobial agents are active on carbapenem-resistant bacteria. This study was designed to study molecular epidemiology of carbapenem-resistant Gram-negative bacterial (GNB) isolates from the community and hospital settings. Methods: In this study, non-duplicate GNB were isolated from clinical specimens, and phenotypic test such as modified Hodge test, metallo ?-lactamase E-strip test, etc. were performed on carbapenem-resistant bacteria. Multiplex PCR was performed to identify the presence of blaIMP, blaVIM, blaKPC, blaOXA48, blaOXA23, blaSPM, blaGIM, blaSIM and blaNDM. Minimum inhibitory concentration (MIC) of colistin, fosfomycin, minocycline, chloramphenicol and tigecycline was also determined. Results: Of the 3414 GNB studied, carbapenem resistance was 9.20 per cent and maximum resistance (11.2%) was present at tertiary care centre, followed by secondary care (4%) and primary centre (2.1%). Among the carbapenem-resistant bacteria, overall, the most common isolate was Pseudomonas aeruginosa (24%). On multiplex PCR 90.3 per cent carbapenem-resistant isolates were positive for carbapenemase gene. The blaNDM(63%) was the most prevalent gene followed by blaVIM(18.4%). MIC results showed that 88 per cent carbapenem-resistant Enterobacteriaceae were sensitive to fosfomycin, whereas 78 per cent of P. aeruginosa and 85 per cent Acinetobacter spp. were sensitive to colistin. Interpretation & conclusions: Carbapenem resistance in GNB isolates from the community and hospital settings was found to be on the rise and should be closely monitored. In the absence of new antibiotics in pipeline and limited therapeutic options, prudent use of antibiotics and strict infection control practices should be followed in hospital to limit the emergence and spread of multidrug-resistant bacteria.
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OBJECTIVE: To analyze carbapenemases genotype of imipenem-resistant Gram-negative bacilli in intensive care unit (ICU) of 3 third grade class A hospitals from Qingdao area, so as to provide reference for drug-resistant bacteria infection prevention and treatment in clinic. METHODS: From Jan. 2013 to Jun. 2016, each 60 strains of imipenem-resistant Klebsiella pneumoniae (IRKP), imipenem-resistant Pseudomonas aeruginosa (IRPA) and imipenem-resistant Acinetobacter baumanii (IRAB) were collected from 3 third grade class A hospitals from Qingdao area. Drug sensitivity test was performed by using Kirby-Bauer method. Phenotypes of carbapenemases were determined by Carba NP trial. PCR was applied to amplify carbapenemase gene; Sanger seqnencing method was adopted for bi-directional sequencing; Blast comparison with GenBank database was conducted. RESULTS: Three kinds of imipenem-resistant Gram-negative bacilli showed high drug resistance to majority commonly used antibiotics as piperacillin, cefazolin, imipenem and cilastatin sodium, gentamicin, etc., but were sensitive to polymyxin B (resistance rate of 0). Among 180 drug-resistant strains, there were 52 strains of class A carbapenems, 13 strains of class B carbapenems and 39 strains of class D carbapenems; the detection rates of them were 28. 89％, 7. 22％ and 21. 67％, respectively. There were 52 strains of KPC-2 gene (IRKP), 4 strains of IMP-1 gene (IRPA), 8 strains of VIM-2 gene (7 strains of IRPA, 1 strain of IRAB), 39 strains of OXA-23 gene (IRAB); the detection rates of them were 28. 89％, 2. 22％, 4. 44％, 21. 67％; all strains were not detected 1MP-2, VIM-1, NDM-1, OXA-24, OXA-58 genes. Results of Blast comparison showed that above detected genes were absolutely homology with the corresponding genes in GenBank database. CONCLUSIONS: Drug resistance of imipenem-resistant Gram-negative bacilli in ICU of 3 third grade class A hospitals is serious in this region, which are nearly no-sensitive to most of commonly used antibiotics in clinic. Main genotypes included KPC-2 (K. pneumoniae), OXA-23 (A. baumanii) and IMP-1 and VIM-2 (P. aeruginosa).
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Objective To investigate the clinical application of Carba NP test in detecting carbapenem-resistant enterobacteriaceae.Methods Routine method was adopted to identify the 51 strains from clinical isolates and K-B test was conducted to screen out the carbapenem-resistant enterobacteriaceae and detect antimicrobial susceptibility.E-test was used to detect the minimum inhibitory concentration (MIC)of carbapenems.Modified Hodge test (MHT)and Carba NPⅠ test were used to screen out the phenotypes of carbapenemase,respectively. Then Carba NPⅡ test was used to classify carbapenemase which were positive in Carba NP I test.E-test was used for the detection of metalloenzymes.Polymerase chain reaction (PCR)was used for the detection of resistance genes. Results Totally 41 strains were positive in Carba NP 1 test and classified as B-class by Carba NPⅡ test.They were positive in metalloenzyme by E-test and carried NDM-1 gene by PCR.Conclusion Carba NP test can be used conveniently,has high consistency with PCR method,and the result is easy to determine.Therefore,it can be used as a routine laboratory method.
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Objective To investigate the feasibility of modified rapid Carba NP test for the detection of carbapenemase,and analyze the differences between the modified method and Carba NP test.Methods A total of 264 strains of gram-negative bacillus,including 164 carbapenem-resistant strains and 100 sensitive strains,were collected,and their carbapenemase were detected by Carba NP test and the modified rapid Carba NP test,respectively.The differences between the two tests were evaluated based on PCR as a reference.Results Among 164 carbapenem-resistant strains,carbapenemase gene was detected in 144 strains by PCR.The carbapenemase gene was negative in 100 sensitive strains.Among 164 carbapenem-resistant strains,135 were positive for the Carba NP test,while 130 for the modified rapid Carba NP test.One hundred of sensitive strains were negative for the two Carba NP tests.Compared with the results of PCR,the sensitivity,specificity and Kappa value of the Carba NP test were 91.7％ (132/144),97.5％ (117/120) and 0.886,respectively,while those of the modified rapid Carba NP test were 89.6％ (129/144),99.2％ (119/120) and 0.879,respectively.There was no significant difference in the positive rates between Carba NP test and the modified rapid Carba NP test (x2 =1.45,P ＞ 0.05).Conclusion The modified rapid Carba NP test which has high consistency with the PCR method,is faster and cheaper than the Carba NP test,and may be applied to epidemiologic survey and the early monitoring of nosocomial infections.