Phenotypic characterization, detection of virulence factors, and antibacterial susceptibility profile of clinical isolates of Klebsiella pneumoniae

Abstract

Klebsiella pneumoniae has been one of the most occurring bacteria in clinical samples causing community-acquired and nosocomial infections. It has been developing resistance to most antimicrobial agents. These have increased the pathogenicity and the chance for the evolvement of more invasive K. pneumoniae. The study was aimed at the identification and detection of Klebsiella pneumoniae from clinical samples. Some selected virulence factors were detected and the antibacterial susceptibility profile of the isolates was conducted. The incubation period, infective dose, and mortality rate of K.pneumoniae were measured using Baggs albino rats (BALB/c) strain. The isolation and identification of 56 Klebsiella pneumoniae from 223 clinical samples were made. Out of 56 K. pneumoniae isolates, all manifested mucoid phenotype, 44(78.6%) capsule antigen and 13(23.2%) Siderophore. The antimicrobial test conducted identified Zinacef 51(91.1%), Rocephin 50 (89.3%), and Ampiclox 50 (91.1%) as the most resistant. Ciprofloxacin 49 (87.5%), chloramphenicol 35(62.5%), Gentamycin 32(57.1%), and Amoxicillin 28 (50%) were the most susceptible to Klebsiella pneumoniae. The mouse lethality test shows that K. pneumoniae hypermucoviscous strain can cause 41.7% lethality and 66.7% mortality in Baggs Albino rats. Meanwhile an infection dose 105cfu/ml, 107cfu/ml and 109cfu/ml produced an incubation period of 9 days, 7days and 5days. The chi-square test shows no significant association between the isolate and the gender of the patients, but there is a significant association between the samples and isolates identified p <0.05. Likewise, the association between mucoid phenotype, capsule antigen, siderophore, and the type of infection is significant (p<0.05). It is finally concluded that K. pneumoniae is the second most prevailing bacterium causing community-acquired infection the resistant pattern recorded identified the test bacteria as a multidrug-resistant strain and manifestation of the virulent factor depends on the type and site of infection caused by the K. pneumoniae.