No abstract

A cross-sectional survey was carried out in Bangladesh with the sampling of 514 Black Bengal goats on smallholdings to determine the presence of sorbitol non-fermenting (SNF) Shiga toxin-producing E. coli (STEC). Swab samples collected from the recto-anal junction were plated onto cefixime and potassium tellurite added sorbitol MacConkey (CT-SMAC) agar, a selective medium for STEC O157 serogroup, where this serogroup and other SNF STEC produce colourless colonies. The SNF E. coli (SNF EC) isolates obtained from the survey were investigated by PCR for the presence of Shiga toxin-producing genes, stx1 and stx2, and two other virulence genes, eae and hlyA that code for adherence factor (intimin protein) and pore-forming cytolysin, respectively. The SNF EC isolates were also assessed for the presence of the rfbO157 gene to verify their identity to O157 serogroup. The results revealed that the proportions of goats carrying SNF EC isolates and stx1 and stx2 genes were 6·2% (32/514) [95% confidence interval (CI) 4·4-8·7)], 1·2% (95% CI 0·5-2·6) and 1·2% (95% CI 0·5-2·6), respectively. All the SNF STEC tested negative for rfbO157, hlyA and eae genes. The risk for transmission of STEC from Black Bengal goats to humans is low.

The aim of this longitudinal study was to verify the prevalence and antibiotic susceptibility pattern of Escherichia coli (E. coli) in cattle reared on Bathan and intensive farming system in Bangladesh. Fecal materials originated from recto anal junction (RAJ) of 100 cattle used for primary screening on MacConkey agar. The diversities among the pink color colony producing isolates on MacConkey agar were verified by conventional cultural methods and biochemical tests. Phenotypically positive E. coli isolates were further investigated for the variations in the antimicrobial resistance profiles to 10 selected antibiotics, by the disk-diffusion method. This study revealed that the overall prevalence of E. coli was 70% of in the rectal swab sample of cattle. However, the prevalence of E. coli was found significantly higher (p= 0.002) in cattle under intensive farming (84%) than cattle on Bathan (56%). Antibiotic susceptibility pattern shows that among the tested isolates 83%, 73%, 68% and 64% were sensitive to chloramphenicol, gentamicin, ciprofloxacin and ampicillin, respectively. On the other hand, all the 70 (100%) E. coli isolates were found resistant to tetracycline and sulfamethoxazole. A high antibiotic resistance profile was also found against amoxicillin (90%), ampicillin (87%), nalidixic acid (86%) and erythromycin (83%). In total, 24 (34%) isolates were resistant against ≥2 antimicrobials. The result clearly shows that antibiotic resistant E. coli isolates are commonly present in cattle of different management systems (intensive and Bathan). Therefore, careful selection of appropriate antibiotics with optimal doses might be ensured to prevent the emergence of antibiotic resistance bacteria.

Background and Aim:Shiga toxin-producing Escherichia coli (STEC) has emerged as significant foodborne pathogens. Ruminants are the primary reservoir of the zoonotic STEC. In Bangladesh, previous studies reported the presence of STEC in cattle, goat, and sheep; however, there is little information about STEC carriage by buffaloes. This study aimed to determine the occurrence of STEC in healthy (absence of clinical signs and symptoms) buffaloes on smallholdings in Bangladesh and to assess the antimicrobial resistance pattern of identified STEC isolates.Materials and Methods:A total of 100 rectal swab samples were obtained from randomly selected buffaloes on 40 smallholdings in Chittagong Division, Bangladesh. Samples were subjected to bacteriological screening to identify E. coli. All E. coli isolates were examined for the presence of the Shiga toxin-producing genes - Shiga toxin 1 (stx1) and Shiga toxin 2 (stx2) using polymerase chain reaction. The antimicrobial susceptibility of identified STEC isolates was tested using the disk diffusion method.Results:Results show that 71 fecal samples were positive for E. coli in bacteriological screening. The proportion of buffaloes harboring STEC isolates was 11% (11/100) (95% confidence interval [CI] 6.1-18.8], of which 7% (7/100) (95% CI 3.2-13.9) and 4% (4/100) (95% CI 1.2-10.2) carried stx1 and stx2 genes, respectively. Antibiogram revealed that 91% (10/11), 73% (8/11), 55% (6/11), and 55% (6/11) STEC isolates were resistant to tetracycline, sulfamethoxazole-trimethoprim, erythromycin, and ampicillin, respectively. In contrast, 91% (10/11) STEC isolates were sensitive to ciprofloxacin, chloramphenicol, and gentamicin, whereas 73% (8/11) isolates were sensitive to ceftriaxone.Conclusion:This study highlights, for the first time, a significant proportion of fecal samples from healthy buffaloes on smallholdings in Bangladesh harboring antimicrobial-resistant STEC. Transmission of antimicrobial-resistant STEC from buffaloes to humans could pose an added risk to public health in rural Bangladesh.

A crossbreeding experiment between Hilly, a locally adapted chicken type in Bangladesh and Fayoumi, an egg type light chicken breed was carried out to evaluate phenotypic performances and to estimate genetic parameters for body weight and egg production at sexual maturity. Results show the mean hatch weight of Hilly♂ × Fayoumi♀ (H♂×F♀) crosses was 35±0.1 gm. In this study, H♂×F♀ crossbred showed a heavier body weight (1551± 32.0 gm/bird) at 20 weeks in comparison with other indigenous chicken genotypes in Bangladesh. The highest body weight gain was found in 8-10 weeks of age. H♂×F♀ crossbred hens exhibited sexual maturity at an average age of 147.5±1.6 days with an average body weight of 1350± 16.8 gm/bird. The mean weight of eggs at sexual maturity was 33.7±0.5 gm/egg. The estimates of heritability for body weight were ranged from 0.15 to 0.26. We observed a positive genetic correlation between weight at sexual maturity (WSM) and egg weight at sexual maturity (EWSM), meaning that hens with high weight at sexual maturity would produce heavier eggs.Asian J. Med. Biol. Res. June 2018, 4(2): 186-192