Enzymatic quorum quenching increases antibiotic susceptibility of multidrug resistant pseudomonas aeruginosa

There is increasing emergence of multidrug resistant Pseudomonas aeruginosa [MDRPA] strains and drug resistance is positively-correlated with biofilm-forming ability. Since about 10% of P. aeruginosa genome is controlled by quorum sensing [QS], alteration in its antibiotic susceptibility by targeting QS was the focus of the present study. One day biofilms of PAO1 and three urinary tract infection MDRPA isolates [PA2, PA8 and PA18] were formed in 96-well microtiter plate. Biofilms were exposed to concentration gradient of ciprofloxacin and gentamicin to obtain Minimum Biofilm Eradication Concentration [MBEC] by direct enumeration method. Susceptibility of 24 h biofilms was evaluated by treatment with ciprofloxacin and gentamicin per se and in combination with lactonase. The effect was also examined on 72 h biofilms by Scanning Electron Microscopy. Lactonase treatment did not have any effect on growth of the selected strains but 73.42, 69.1, 77.34 and 72.5% reduction of biofilm was observed after lactonase [1 unit] treatment, respectively. Antibiotics in combination with lactonase [0.3 units] resulted in an increased susceptibility of the biofilm forms by > 3.3, 4, 5 and 1.5 folds of MBEC, for ciprofloxacin and > 6.67, 12.5, 6 and > 2.5 folds, for gentamicin respectively, which could be due to the disruption of biofilm by lactonase treatment as shown by scanning electron microscopy. Also there was significant reduction [p < 0.001] in virulence factor production by the strains. Lactonase treatment increased antibiotic susceptibility of the biofilms of MDRPA isolates underscoring the potential of quorum quenching in antimicrobial therapeutics

Superoxide radical formation in isolated PMN from experimental vaginal trichomoniasis

Trichomoniasis, the most widespread sexually transmitted disease is caused by Trichomonas vaginalis. This parasite is site specific for the genitourinary tract and recruitment of macrophages as well as polymorphonuclear nutrophils [PMN] to the site of infection is the first line of defense as a component of non-specific resistance and immunity. In this study, BALB/c mice were infected with 10 isolates from symptomatic and 10 from asymptomatic patients. Then PMN from vaginal washes, vaginal tissue and blood of infected mice was isolated and the rate of superoxide formation by intact stimulated PMN was measured. Results showed that, mice infected with symptomatic isolates indicated significant increase in polymorphs with increase in days of infection as compared with mice infected with asymptomatic isolate and control [uninfected] animals. Vaginal tissue cells generated maximal amount of superoxide in symptomatic isolates infected animals [5.17 +/- 0.36] as compared to asymptomatic isolates [4.54 +/- 0.43], which brings out the maximal abnormality in PMN in this localized area. The amount of superoxide radicals generated by cells of vaginal washes and blood of symptomatic isolate infected mice] 4.29 +/- 0.25 and 2.16 +/- 0.35] was less than the asymptomatic isolate [4.94 +/- 0.49 and 3.18 +/- 0.26], respectively. This study indicates that super oxide radical generation may play role in establishing the infection

Evaluation of trichomonas vaginalis isolates from symptomatic and asymptomatic patients in mouse model

Trichomoniasis, a worldwide prevalent infection, is a perfect example of interplay between the infecting parasite and the host, on which the presentation of disease depends. To study the pathogenesis, animal model is required for establishment of infection. In this study, by using strains of Trichomonas vaginalis isolated from vaginal swabs and/or urine samples and maintained in axenic form from 10 symptomatic and 10 asymptomatic female patients, the infections in BALB/c mice have been evaluated. Based on parasitic load, experimental peak infection in vagina of estradiol and L. acidophilus treated female BALB/c mice was observable on 5[th] post infection day. This was significantly higher in mice infected with isolates from symptomatic patients in comparison to the other group. Gradual increase up to day 5 followed by decline in parasites, polymorphs and vaginal epithelial cells was observed in mice infected with isolates from symptomatic subjects in contrast to mice infected with asymptomatic patients' isolates or control animals at all time intervals