Coexistence of blaNDM-1, blaOXA-51, blaOXA-23, and armA in conjunction with novel mutations detected in RND efflux pump regulators in tigecycline resistant clinical isolates of Acinetobacter baumannii.

This study has investigated a total of 51 Acinetobacter baumannii isolates for the prevalence of resistant determinants in tigecycline susceptible and non-susceptible clinical isolates of A. baumannii. Antimicrobial susceptibility testing revealed 74% of isolates were tigecycline resistant. Mutations in RND-efflux pump regulatory genes and the expression of efflux pump genes were measured in tigecycline resistant isolates. There was a strong co-relation between the blaNDM-1 and armA wherein majority of the isolates that are positive for blaNDM-1 have also harbored armA. Compared with TSAB (tigecycline susceptible A. baumannii), TNAB (tigecycline non-susceptible A. baumannii) isolates show increased distribution of blaNDM-1 (P = 0.048), blaIMP-1 (P< 0.0001) and blaOXA-51 (P = 0.0029) carbapenemase genes. The variants of RND-efflux pump regulatory genes due to amino-acid mutations in adeS (F12S, K84E, W61R, N268H and Q299R) and adeL (G21R and Q262R) were identified in tigecycline resistant isolates as well as ISAba1 mediated disruption of adeN were observed causing overexpression of adeIJK efflux pump. Additionally, mutations in adeRS were also associated with increased expression of adeABC efflux pump. Besides, TNAB isolates showed significantly (P< 0.0001) higher ability of biofilm formation as compared to TSAB isolates. The tigecycline resistance due to mutations in contemporary A. baumannii isolates having a higher ability to form biofilm may pose therapeutic difficulties.

Inhibitory Effect of Zinc Sulfate on Clinical Isolates of Pseudomonas aeruginosa and Acinetobacter baumannii.

This objective of the study was to determine the inhibitory effect of zinc sulfate against the clinical isolates of Pseudomonas aeruginosa and Acinetobacter baumannii. The inhibitory effect of zinc sulfate was determined against the 120 clinical isolates (60 isolates of P. aeruginosa and 60 isolates of A. baumannii) by agar dilution method. The findings indicate that zinc has an inhibitory effect on the clinical isolates of P. aeruginosa and A. baumannii at a concentration ranging from 0.25to 1mg/ml of zinc sulfate by agar dilution method.

A rare case of diphyllobothriasis from Pondicherry, South India.

Diphyllobothriasis is an intestinal parasitic infection caused by the ingestion of raw fresh-water fish containing the infectious larvae of Diphyllobothrium spp. This infection is uncommon in India. We report a case of diphyllobothriasis that occurred in Pondicherry, India, in a 5-year-old boy hailing from a fishing community. He attended the Pediatric OPD with spontaneous discharge of segments of the adult parasite. The segments (macroscopically and microscopically) were identified as those of Diphyllobothrium latum. The stool examination also revealed characteristic oval eggs.

A new serum hydatid antigen detection test for diagnosis of cystic echinococcosis.

Cystic echinococcosis (CE) is a major public health problem with a worldwide distribution in both humans and animals. Diagnosis of this disease by simple and rapid immunoassays is a priority. The objective of the present study was to standardize and evaluate the latex agglutination test (LAT) as a simple test for the detection of circulating hydatid antigen in serum. The subjects in this study included 141 patients in the following groups: surgically confirmed CE cases (18), ultrasound-proven cases (26), presumptive CE cases (47), controls with other parasitic disease (25), and healthy controls (25). A polystyrene latex (0.81 microm) suspension was used as a carrier particle for hydatid antibodies in the test. The latex particles were sensitized with hyperimmune hydatid antiserum raised in rabbits. The hydatid antibody-sensitized latex particles were used for the detection of hydatid antigens in serum. The results of the study showed that the LAT could detect the circulating hydatid antigen in 13 (72%) of 18 patients with surgically confirmed CE, 17 (65%) of 26 patients with ultrasound-proven CE, and 19 (40%) of 47 presumptive cases of CE. The test detected antigen in 1 (4%) of 25 controls with other parasitic disease, and no antigen was detected in the serum of 25 healthy controls. The LAT showed a sensitivity of 72%, a specificity of 98%, a positive predictive value of 93%, and a negative predictive value of 91%. The present study is the first report of the LAT for the detection of hydatid antigen in serum in the diagnosis of CE.