Therapeutic Alternatives for Multiple Drugresistant Bacterial Isolates

Abstract

Worldwide emergence of multiple drug resistance among bacterial pathogens is agrowing health problem and demands for its proper monitoring and control in differentclinical settings. This study aimed to determine the prevalence of multidrug resistanceand ESBL production among various clinical bacterial isolates and to search for effectivetherapeutic alternatives. A total of 2141 various clinical specimens including urine,sputum, throat swabs, eye and ear specimens, pus and body fluids received atmicrobiology laboratory of National PublicHealth Laboratory, Nepal, from March, 2009to February, 2010, were processed and isolates were identified following standardmicrobiological procedures. Antibiotic susceptibility testing and ESBL detection wasdone by Disk Diffusion methods according to CLSI guidelines. Of the 2141 variousclinical specimens processed, 20.2% showed significant growth,64.9% isolates wereMDR and most of them (78.1%) were urinary isolates. Significant MDR phenotype wasseen among major gram negative pathogens such asP. aeruginosa(92.3%),Klebsiellaspp. (82.4%),E. coli (75.5%),Acinetobacterspp. (71.4%) andC. freundii (66.7%), andgram positiveE. faecalis(80.0%) andS. aureus(52.5%). Of the 142 MDR isolates testedfor ESBL production, 59.9% isolates produced ESBLs andE. coli (77.6%) remainedpredominant ESBL producer followed byK. oxytoca (75.0%). Among conventionalantibiotics, nitrofurantoin and chloramphenicol were effective against most MDRisolates. Clindamycin and vancomycin remained the drug of choice for MRSA isolates.Temocillin, meropenem, imipenem, and combination of cefepime, ceftazidime andcefotaxime with clavulanate were effective against most ESBL producers. Resistancerates for fluoroquinolones (75.4-97.6%) and aminoglycosides (44.4-85.2%) wererelatively higher. Fosfomycin was found to be the best drug against all MDR isolateswith lowest resistance (17.6%) followed by tigecycline (23.2%). ESBL production andincreased spectrum of drug resistance was statistically significant (p<0.05). To the best ofour knowledge, the study reports resistance patterns of MDR clinical bacterial isolates tofosfomycin, temocillin and tigecycline for the first time in Nepal. The higherpredominance of ESBL production and MDR phenotypes among common clinicalisolates mandates proper control measures and more potent drugs. Key words: ESBL, MDR, fosfomycin,temocillin,tigecycline, Nepal