Anandkumar H

Abstract

Background: The attachment of the bacteria to the host cell and ability to invade the cell are regarded as important steps in the infectious process. The hydrophobicity of the microbial surface plays a critical role in the adherence of bacteria to the surface. The ability of biofilm formation can increase survival chance of microorganism, as cell growing in biofilm are highly resistant to the components of the immune system and many antimicrobial agents. Infection caused by ESBL- producers are associated with severe adverse outcomes and may be related to increased virulence of these strains. Materials and Methods: A total of 100 urinary E.coli were selected for the study, of which 50 strains were from ESBL producers and 50 from non- ESBL-producing uropathogenic E. coli (UPEC) strains. The urinary E. coli isolates that were resistant to at least one of the three indicator cephalosporins (cefotaxime, cefpodoxime and ceftazidime) were tested for ESBL production by quantitative E-strip method. All the 100 urinary Escherichia coli strains were tested for cell surface hydrophobicity (CSH) by salt aggregation method and Biofilm production by tissue culture plate method. Results: Among ESBL producers, 19 (38%) were CSH positive and 34 (68%) were biofilm producers. However among non-ESBL producers, 05 (10%) were CSH positive and 12 (24%) were biofilm producers. Statistically significant difference ( Conclusion: In the present study, it was found that the ESBL producing isolates had a higher ability to form biofilm and CSH; both of them are among the important virulence factors associated with cell surface adherence which is the first step in bacterial infection. Keywords: Uropathogenic E.coli, Virulence factors, ESBL

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Abstract

Objectives: The study was aimed to identify the occurrence of extended spectrum of Beta lactamases (ESBLs), to compare different phenotypic methods used for the confirmation and to evaluate the antibiotic resistance pattern in ESBL producing uropathogenic Escherichia coli. Materials and Methods: The Escherichia coli strains were isolated from urine and the isolates resistance to at least one of the three representative cephalosporins (cefotaxime, cefpodoxime and ceftazidime) was tested for ESBL production by Double disc synergy test (DDST), Inhibitory potentiated disc diffusion (IPDD) test and quantitative E-strip method. Result: Of 120 Escherichia coli strains isolated, 62(51.6%) were resistant to at least one of the three cephalosporins and 28 (45.1%) were positive for ESBL by IPDD and E-strip test. However, 9 (14.5%) strains were positive by DDST method. Among third generation cephalosporins, cefpodoxime was (45.8%) better screening indicator followed by ceftazidime (40.0%) and cefotaxime (37.5%). Most of the ESBL producers (97.3%) were resistant to three or more drugs, compared to (51.2%) non-ESBL producers. Conclusion: The acceptable method for detection of ESBL producing E.coli were IPDD and E-strip tests compared to DDST with better sensitivity (100%), specificity (95.8%) and positive predictive value (96.5%). ESBL producers showed significantly (p amikacin compared to non ESBL producers. Keywords : Uropathogenic E coli, Drug resistance, Extended spectrum beta lactamase 2.

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Abstract

Background and Objectives:  Accuracy and promptness in the detection of methicillin resistance are of key importance in ensuring correct antibiotic treatment in infected patients and control of MR staphylococci in the hospital environment. The aim of this study was to detect MRSA phenotypically by oxacillin screen agar and Oxacillin MIC method and to evaluate cefoxitin disc diffusion test as a screening tool for MRSA detection. Materials and Methods: In the present study, a total of 50 isolates of from various clinical samples collected were used for the detection of Methicillin resistant (MRSA). Methicillin resistance was determined by oxacillin disc diffusion, cefoxitin disc diffusion the oxacillin screen agar test and MIC. Result: Out of 50 isolates 21 (42%) isolates were detected as MRSA based on MIC method, which is considered as gold standard method for the detection of MRSA. All the isolates of MRSA were 100% susceptible to vancomycin and linezolid. rnIn the present study, cefoxitin diffusion method has given 100% sensitivity and specificity in concordance with MIC method. However, the oxacillin screen agar method showed 95.24% sensitivity and 96.55% specificity. Conclusion: As per our study and previous reports elsewhere on phenotypic detection of MRSA, cefoxitin is more potent inducer of the regulatory system and an accurate surrogate marker for the detection of MRSA in the routine susceptibility testing. Keywords: MRSA, Cefoxitin, Drug Resistance.

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