Antibiotic resistance patterns of Staphylococcus spp. isolated from fast foods sold in different restaurants of Mymensingh, Bangladesh

OBJECTIVE

Fast foods are often responsible for staphylococcal foodborne illness. The present study was carried out to isolate Staphylococcus spp. from various fast foods sold in Mymensingh and to determine their antibiogram.

MATERIALS AND METHODS

Overall, 60 samples of fast foods sold in different restaurants were screened by culture, biochemical tests, and polymerase chain reaction (PCR) to isolate and identify Staphylococcus spp., followed by employing of disk diffusion method to determine their antibiotic resistance patterns.

RESULTS

Among these 60 samples, 8 [13.33%, 95% confidence interval (CI): 6.91%-24.17%] were positive for Staphylococcus spp. by cultural and biochemical properties. By PCR, four (6.67%, 95% CI: 2.62%-15.93%) isolates were confirmed as Staphylococcus aureus by targeting nuc gene. Additionally, all the S. aureus isolates were coagulase-positive. By antibiogram profiles, all the Staphylococcus isolates exhibited resistance to azithromycin and erythromycin (95% CI: 67.56%-100.00%), and frequently resistance to cefixime (75%, 95% CI: 40.93%-95.56%), ampicillin (50%, 95% CI: 21.52%-78.48%), and amoxicillin (37.5%, 95% CI: 13.68%-69.43%); moderate to lower resistance was found against cefotaxime, gentamicin, and doxycycline. In addition, all the isolates were sensitive to ciprofloxacin and chloramphenicol. Interestingly, 75% (6/8; 95% CI: 40.93%-95.56%) isolates were multidrug-resistant (MDR) in nature. Furthermore, the indices of multiple antibiotic resistance (MAR) were ranged from 0.2 to 0.6.

CONCLUSION

This study revealed that fast foods sold in restaurants were contaminated with MDR and MAR Staphylococcus isolates, having potential public health significance.

Prevalence of Virulence Genes of Diarrheagenic Escherichia coli in Fecal Samples Obtained from Cattle, Poultry and Diarrheic Patients in Bangladesh

Using multiplex real-time PCR, 960 fecal samples collected from poultry, cattle, and patients with diarrhea in Bangladesh were screened for diarrheagenic Escherichia coli (DEC). The invasion-related gene virB showed the highest prevalence in human patients (41%) and was shown to be positively correlated first with afaB with regards to diffuse adhesion and second with aggR with regards to aggregative adhesion. These three genes were specific to human patients. In contrast, the Shiga toxin genes stx1 (57%) and stx2 (40%) were prevalent in cattle samples. The eae gene, which is associated with attaching and effacing lesion formation, and the elt and est genes, which are associated with enterotoxins, were detected from all three sample sources. Heat map construction and hierarchical clustering assigned the samples into five different clusters, with the patient samples positive for virB and afaB being placed together in one cluster. Although the detection of virulence genes cannot be a direct indication of the distribution of diarrheagenic organisms, their detection suggests that Shigella spp. or enteroinvasive E. coli are the most prevalent diarrheagenic bacteria in Bangladesh and that diffusely adherent E. coli is concomitantly present with these bacteria. eae-possessing organisms in patients may come from cattle and poultry sources. The small number of stx-positive patients could be explained by the small number of animal samples that were positive for both eae and stx.

Surveillance, epidemiological, and virological detection of highly pathogenic H5N1 avian influenza viruses in duck and poultry from Bangladesh

Avian influenza viruses (AIVs) continue to pose a global threat. Waterfowl are the main reservoir and are responsible for the spillover of AIVs to other hosts. This study was conducted as part of routine surveillance activities in Bangladesh and it reports on the serological and molecular detection of H5N1 AIV subtype. A total of 2169 cloacal and 2191 oropharyngeal swabs as well as 1725 sera samples were collected from live birds including duck and chicken in different locations in Bangladesh between the years of 2013 and 2014. Samples were tested using virus isolation, serological tests and molecular methods of RT-PCR. Influenza A viruses were detected using reverse transcription PCR targeting the virus matrix (M) gene in 41/4360 (0.94%) samples including both cloacal and oropharyngeal swab samples, 31 of which were subtyped as H5N1 using subtype-specific primers. Twenty-one live H5N1 virus isolates were recovered from those 31 samples. Screening of 1,868 blood samples collected from the same birds using H5-specific ELISA identified 545/1603 (34%) positive samples. Disconcertingly, an analysis of 221 serum samples collected from vaccinated layer chicken in four districts revealed that only 18 samples (8.1%) were seropositive for anti H5 antibodies, compared to unvaccinated birds (n=105), where 8 samples (7.6%) were seropositive. Our result indicates that the vaccination program as currently implemented should be reviewed and updated. In addition, surveillance programs are crucial for monitoring the efficacy of the current poultry vaccinations programs, and to monitor the circulating AIV strains and emergence of AIV subtypes in Bangladesh.