RESUMO
BACKGROUND: Escherichia coli accounts for 70%-95% of urinary tract infections (UTIs). UTI is a serious health problem with respect to antibiotic resistance and biofilms formation being the prime cause for the antibiotic resistance. Biofilm can restrict the diffusion of substances and binding of antimicrobials. In this context, the present study is aimed to perform in vitro detection of biofilm formation among E. coli strains isolated from urine and to correlate their susceptibility pattern with biofilm formation. MATERIALS AND METHODS: A total of 100 E. coli strains isolated from patients suffering from UTI were included in the study. The identification of E. coli was performed by colony morphology, Gram staining, and standard biochemical tests. The detection of biofilm was carried out by Congo Red Agar (CRA) method, tube method (TM), and tissue culture plate (TCP) method. Antimicrobial sensitivity testing was performed by Kirby-Bauer disc diffusion method on Muller-Hinton agar plate. RESULTS: Of the 100 E. coli strains, 49 (49%) and 51 (51%) were from catheterized and noncatheterized patients, respectively. Biofilm production was positive by CRA, TM, and TCP method were 49 (49%), 55 (55%), and 69 (69%), respectively. Biofilm producers showed maximum resistance to co-trimoxazole (73.9%), gentamicin (94.2%), and imipenem (11.6%) when compared to nonbiofilm producers. Significant association was seen between resistance to antibiotic and biofilm formation with a P = 0.01 (<0.05). CONCLUSION: A greater understanding of biofilm detection in E. coli will help in the development of newer and more effective treatment. The detection of biofilm formation and antibiotic susceptibility pattern helps in choosing the correct antibiotic therapy.
RESUMO
BACKGROUND: ß-lactamases viz., extended spectrum ß-lactamase (ESBL), AmpC, and metallo ß-lactamase (MBL) production in Klebsiella pneumoniae has led to a serious concern about septicemic neonates in Neonatal Intensive Care Units due to high resistance against commonly used antimicrobials. PURPOSE: To study the prevalence of ESBL, AmpC, and MBL production in K. pneumoniae isolates in neonatal septicemia, to check antimicrobial susceptibility to various drugs including tigecycline; and to assess burden of multiple drug resistance (MDR). MATERIALS AND METHODS: Total 24 clinical isolates of K. pneumoniae isolated from 318 blood samples of suspected cases of neonatal septicemia were studied. Isolates were screened for ESBL, AmpC, and MBL production by Clinical and Laboratory Standards Institute (CLSI) disk method, AmpC cefoxitin screen, and imipenem, meropenem, ceftazidime disk screen respectively; and confirmation was done by CLSI phenotypic disk confirmatory test, AmpC sterile disk method, and imipenem ethylenediamine tetracetic acid double disk synergy test respectively. Antimicrobial susceptibility was determined by Kirby-Bauer's disk diffusion method. Efficacy of tigecycline was evaluated using United States Food and Drug Administration guidelines. RESULTS: Of the 24 K. pneumoniae isolates, co-production of AmpC + MBL was found in more number of isolates (67%) (P < 0.0001) compared to single enzyme production (ESBL and MBL 8% both, AmpC 12.5%). Rate of resistance for penicillins and cephalosporins was highest. Susceptibility was more for imipenem, co-trimoxazole, and meropenem. Nonsusceptibility to tigecycline was low (21%). A total of 23 (96%) isolates were MDR. CONCLUSIONS: Routine detection of ESBL, AmpC, and MBL is required in laboratories. Carbapenems should be kept as a last resort drugs. Trend of tigecycline susceptibility has been noted in the study. Continued monitoring of susceptibility pattern is necessary to detect true burden of resistance for proper management.
