Faecal carriage of extended spectrum beta-lactamase (ESBL) and New Delhi metallo beta-lactamase(NDM) producing Escherichia coli between piglets and pig farmworkers.

A cross-sectional study on five organized pig farms was conducted to assess the faecal carriage of ESBL and blaNDM carbapenemase-producing E. coli in piglets and pig farmworkers. Faecal samples from piglets (n = 155) and pig farmworkers (n = 21) were processed for isolation and characterization of E. coli. A total of 124 E. coli isolates from piglets and 21 E. coli isolates pig farmworkers were recovered and screening for ESBL production showed that 44.4 % (55/124) of the isolates from piglets and 42.9 % (9/21) of the isolates from farmworkers were ESBL positive. The ESBL positive isolates from piglets and farmworkers harbored blaCTX-M and also co-harbored other beta-lactams, sulphonamide, quinolone and tetracycline resistance genes. Diarrhoeic (50%, 49/98) and crossbred piglets (52.7%, 39/74) harbored a significantly higher number of ESBL producing isolates than non-diarrhoeic (23.1 %, 6/26) and purebred piglets (32%, 16/50) (p < 0.05). Piglets and pig farmworkers harbored nine and two carbapenem-resistant isolates, respectively. Interestingly, two isolates from piglets and one isolate from farmworkers harbored the blaNDM gene. The blaNDM positive E. coli isolated from piglets and farmworkers of the same farm revealed similar antibacterial resistance patterns, resistant genes, sequence (ST-167) and plasmid type (IncX3). In India, carbapenems are not used in food animal treatment, hence carbapenem resistant E. coli in piglets possibly originated from the human contact or common environment and is of public health importance.

Development of a recombinant TaSP-based Dot-ELISA for detection of Theileria annulata infection in cattle.

The study was conducted to develop and validate Dot-ELISA for the diagnosis of Theileria annulata infection in cattle using recombinant Theileria annulata surface protein (r-TaSP). The r-TaSP based indirect plate-ELISA was used as a reference test to compare the efficacy of the Dot-ELISA. The Dot-ELISA was optimized with 500 ng of antigen per dot, 1:150 dilution of serum and 1:1000 dilution of secondary antibody for positive and negative reaction. A total of 17 confirmed positive, 25 negative and 129 field sera samples were used to calculate the diagnostic accuracy of Dot-ELISA in comparison with indirect plate-ELISA. The diagnostic sensitivity and specificity of the Dot-ELISA was 95.8 per cent (95% CI, 93.1-97.2) and 80 per cent (95% CI, 48.1-96.2), respectively. The positive predictive value (PPV) of Dot-ELISA was 98.2 percent (95% CI, 95.5-99.7) and negative predictive value (NPV) was 61.6 percent (95% CI, 37-74). The positive and negative likelihood ratios were 4.79 (95% CI, 1.8-25.69) and 0.053 (95% CI 0.03-1.4), respectively. The Dot-ELISA showed moderate agreement (k value, 0.67, 95% CI, 0.36- 0.82) with indirect plate-ELISA. The developed Dot-ELISA is less expensive and convenient for the diagnosis of T. annulata infection in cattle under field conditions.

Molecular characterisation of blaOXA-48 carbapenemase-, extended-spectrum ß-lactamase- and Shiga toxin-producing Escherichia coli isolated from farm piglets in India.

OBJECTIVES: The aim of this study was to characterise carbapenemase-, extended-spectrum ß-lactamase (ESBL)- and Shiga toxin-producing Escherichia coli isolated from farm piglets in India. METHODS: Faecal samples (n=741) from 10 organised pig farms, including non-diarrhoeic (n=546) and diarrhoeic (n=195) piglets, were processed for isolation of carbapenem-resistant and ESBL-producing E. coli. RESULTS: A total of 27 and 243 isolates were phenotypically confirmed as carbapenem-resistant and ESBL-producers, respectively. The meropenem minimum inhibitory concentration (MIC) of carbapenem-resistant isolates ranged from 8-128µg/mL. On genotypic screening of the 27 carbapenem-resistant isolates, 3 isolates were positive for the blaOXA-48 carbapenemase gene; no other carbapenemase genes were detected. The 243 ESBL-producing isolates were positive for blaCTX-M-1 (n=135), qnrA (n=92), qnrB (n=112), qnrS (n=49), tetA (n=42), tetB (n=45) and sul1 (n=43). The Shiga toxin virulence markers stx1 and stx2 were detected in 41 and 38 of the 243 phenotypic ESBL-producing isolates, respectively. Multilocus sequence typing (MLST) of blaOXA-48-positive E. coli isolates showed ST10- and ST5053-like sequence types. CONCLUSION: This is the first report on the presence of blaOXA-48-carrying E. coli in piglets in India, which pose a potential risk to public health.