Badrul Hasan

Antimicrobial Drug–Resistant Escherichia coli in Wild Birds and Free-range Poultry, Bangladesh

Multidrug resistance was found in 22.7% of Escherichia coli isolates from bird samples in Bangladesh; 30% produced extended-spectrum β-lactamases, including clones of CTX-M genes among wild and domestic birds. Unrestricted use of antimicrobial drugs in feed for domestic birds and the spread of resistance genes to the large bird reservoir in Bangladesh are growing problems.

High Prevalence of Antibiotic Resistance in Pathogenic Escherichia coli from Large- and Small-Scale Poultry Farms in Bangladesh

SUMMARY. Antibiotic resistance in avian bacterial pathogens is a common problem in the Bangladesh poultry industry. The aim of the present study was to provide information on the present status of antibiotic resistance patterns in avian pathogenic Escherichia coli in Bangladesh. Of 279 dead or sick poultry of different ages, 101 pathogenic E. coli strains isolated from broilers and layer hens with colibacillosis infections were screened to determine phenotypic expression of antimicrobial resistance against 13 antibiotics used in both veterinary and human medicine in Bangladesh. Of 101 pathogenic E. coli isolates, more than 55% were resistant to at least one or more of the tested compounds, and 36.6% of the isolates showed multiple–drug-resistant phenotypes. The most common resistances observed were against tetracycline (45.5%), trimethoprim-sulphamethoxazole (26.7%), nalidixic acid (25.7%), ampicillin (25.7%), and streptomycin (20.8%). Resistance to ciprofloxacin (12.9%), chlormaphenicol (8.9%), nitrofurantoin (2%), and gentamicin (2%) was also observed, and none of the isolates were resistant to tigecycline as well as extended spectrum beta-lactamase (ESBL) producers. One isolate was resistant to cefuroxime (1%), cefadroxil (1%), and mecillinam (1%) but was not an ESBL producer. Resistance rates, although significant in Bangladeshi isolates, were found to be lower than those reported for avian isolates from the Republic of Korea and clinical, avian, and environmental isolates from Bangladesh. The high level of antibiotic resistance in avian pathogens from Bangladesh is worrisome and indicates that widespread use of antibiotics as feed additives for growth promotion and disease prevention could have negative implications for human and animal health and the environment.

Antibiotic resistance patterns in Escherichia coli from gulls in nine European countries

Background The prevalence of antibiotic resistant faecal indicator bacteria from humans and food production animals has increased over the last decades. In Europe, resistance levels in Escherichia coli from these sources show a south-to-north gradient, with more widespread resistance in the Mediterranean region compared to northern Europe. Recent studies show that resistance levels can be high also in wildlife, but it is unknown to what extent resistance levels in nature conform to the patterns observed in human-associated bacteria. Methods To test this, we collected 3,158 faecal samples from breeding gulls (Larus sp.) from nine European countries and tested 2,210 randomly isolated E. coli for resistance against 10 antibiotics commonly used in human and veterinary medicine. Results Overall, 31.5% of the gull E. coli isolates were resistant to ≥1 antibiotic, but with considerable variation between countries: highest levels of isolates resistant to ≥1 antibiotic were observed in Spain (61.2%) and lowest levels in Denmark (8.3%). For each tested antibiotic, the Iberian countries were either the countries with the highest levels or in the upper range in between-country comparisons, while northern countries generally had a lower proportion of resistant E. coli isolates, thereby resembling the gradient of resistance seen in human and food animal sources. Conclusion We propose that gulls may serve as a sentinel of environmental levels of antibiotic resistant E. coli to complement studies of human-associated microbiota.

The gull (Chroicocephalus brunnicephalus) as an environmental bioindicator and reservoir for antibiotic resistance on the coastlines of the Bay of Bengal.

The presence and frequency of multiresistant bacteria in wild birds act as indicators of the environmental contamination of antibiotic resistance. To explore the rate of contamination mediated by Escherichia coli, 150 fecal samples from the brown-headed gull (Chroicocephalus brunnicephalus) and 8 water samples from the Bay of Bengal area were collected, cultured, and tested for antibiotic susceptibility. Special attention was paid to extended-spectrum beta-lactamase (ESBL)-producing isolates, which were further characterized genetically. Antibiotic resistance was found in 42.3% (36/85) of the E. coli isolates and multidrug resistance in 11.8%. Isolates from the area with a higher human activity were more resistant than those from an area with a lower level of activity. Most frequent was resistance to ampicillin (29.4%), followed by trimethoprim-sulfamethoxazole (24.7%) and quinolones (22.4%). Carriage of ESBL-producing E. coli was relatively high (17.3%) in the gulls, whereas no ESBL producers were found in the water. All ESBL-producing E. coli isolates, but one, carried bla(CTX-M-15) or bla(CTX-M-15)-like genes. A bla(CTX-M-14)-like enzyme was found as an exception. Gulls from two different colonies shared E. coli clones and harbored the clinically relevant sequence types ST10, ST48, and ST131. The high frequency of antibiotic resistance and ESBL production among E. coli isolates from gulls indicates that the environmental contamination of antibiotic resistance has already gone far on the coastlines of the Bay of Bengal. Considering the limited control over the antibiotic consumption and waste from human activities in Bangladesh, there is no easy solution in sight.

Emergence of carbapenem-resistant Acinetobacter baumannii in hospitals in Pakistan.

The emergence of pan-resistance in bacterial pathogens poses a threat to human health. Carbapenem-resistant Acinetobacter baumannii has emerged as a serious challenge, causing nosocomial infection and community-acquired outbreaks in hospitals globally, including in Pakistan. We collected 90 Acinetobacter isolates from patients with secondary or nosocomial infections from different hospitals in Pakistan and screened for carbapenem-resistant strains. Of the 90 isolates, 59 were resistant to carbapenems. Among oxacillinase -encoding genes, blaOXA-51-like was common in all isolates, including in combination with blaOXA-23-like in 14 isolates; however, blaOXA-24-like and blaOXA-58-like were completely absent. Among metallo-β-lactamase-encoding genes, only blaNDM-1 was found in one isolate, while the other three genes, blaIMP, blaVIM and blaSIM, were completely absent. None of the isolates was found to harbour the blaCTX-M gene. The isolates were also tested for susceptibilities to a panel of different antibiotics belonging to several classes. Of all the drugs tested, tigecycline was the most effective with 80 % sensitivity amongst isolates, followed by colistin with 50 % sensitivity. Three categories of resistance were found in these isolates: extreme drug resistance in 26, pan-drug resistance in 19 and multidrug resistance in 87 isolates. The isolates exhibited a high resistance to cephalosporins, trimethoprim-sulfamethoxazole and β-lactam antibiotics, followed by tetracycline and β-lactam/β-lactam inhibitor combination, fluoroquinolone and aminoglycosides. The results show a prominent level of antibiotic-resistance phenotypes in A. baumannii and strongly suggest the need for full-scale national surveillance of carbapenem-resistant A. baumannii with particular emphasis on the newly identified NDM-1 (New Delhi metallo-β-lactamase-1).

Antimicrobial-resistant and ESBL-producing Escherichia coli in different ecological niches in Bangladesh

Introduction The rapid and wide-scale environmental spread of multidrug-resistant bacteria in different ecosystems has become a serious issue in recent years. Objectives To investigate the epidemiology of antimicrobial resistance and extended spectrum beta-lactamase (ESBL) in Bangladeshi wild birds and aquatic environments, samples were taken from Open Bill Stork (Anastomus oscitans) (OBS) and the nearby water sources. Methods Water and fresh fecal samples were collected from several locations. All samples were processed and cultured for Escherichia coli and tested for antibiotic susceptibility against commonly used antibiotics. ESBL producers were characterized at genotypic level using polymerase chain reaction (PCR), sequencing, multilocus sequence typing, and rep-PCR. Results and discussion A total of 76 E. coli isolates from the 170 OBS and 8 E. coli isolates from three river sources were isolated. In total, 29% of E. coli isolated from OBS and all of the E. coli isolated from water sources were resistant to at least one of the tested antimicrobials. Resistant phenotypes were observed with all antimicrobials except tigecycline, gentamicin, imipenem, and chloramphenicol. Multidrug resistance was observed in 2.6% of OBS and 37.5% of the water isolates. Also, 1.2% of the ESBL-producing E. coli were isolated from OBS, whereas 50% of the E. coli isolated from water sources were ESBL producers possessing the CTX-M-15 gene. The most concerning aspect of our findings was the presence of human-associated E. coli sequence types in the water samples, for example, ST156-complex156, ST10-complex10 and ST46. Conclusion This study reports the presence of multidrug-resistant ESBL-producing E. coli in OBSs and nearby aquatic sources in Bangladesh.

Dissemination of NDM-1

The dissemination of members of the Enterobacteriaceae family with extended spectrum beta-lactamases (ESBLs) and metallo-beta-lactamases (MBLs) has become a global concern. ESBLs and MBLs have been reported in humans, domestic animals, wildlife and the environment, and their isolation frequencies are increasing rapidly worldwide. Most studies have been performed in developed countries and quite few in developing countries, where the antibiotic consumption is often poorly controlled. To explore the environmental contamination of antibiotic resistance in Bangladesh, and of ESBLs and MBLs in particular, fecal samples from poultry and wild birds were studied in this thesis.Samples were collected from both sick birds (poultry having Escherichia coli infections) and healthy birds (free-range poultry, seagulls and crows) residing in different environmental niches. Samples from patients and fresh/sea water were included, to follow the chain of antibiotic resistance in bacteria from humans to the environment. Information regarding the antibiotic usage in poultry production was also collected. The susceptibility of avian E. coli isolates cultured with and without selective pressure was tested against antibiotics commonly used in human and veterinary medicine in Bangladesh. Special attention was paid to ESBL-producing isolates, which were further characterized genetically.The results of the studies showed that E. coli isolates from commercial poultry, free-range poultry, gulls and crows were resistant to several classes of antibiotics, and that the level and spectrum of antibiotic resistance varied between different bird populations. There was no NDM-producer found among the birds, but ESBL-producing Enterobacteriaceae could be found in up to 59% of the crows, the birds with the highest carriage rate of multiresistant Enterobacteriaceae of all bird species studied. The most common ESBL-type was CTX-M-15, which also is the most common in the human population in Bangladesh. Birds also shared clinically important sequence types with humans, including E. coli clone O25b-ST131.In conclusion, ESBL-producing bacteria with multiresistance are easily spread to wild birds. Their opportunistic feeding behavior at poorly managed hospital waste dumps and nearby water bodies makes them into both reservoirs and active spreaders. The high level of antibiotic resistant and ESBL-producing bacteria in the bird population of Bangladesh is worrying, and there is no easy solution in sight. Nationwide programs are necessary to both improve the management of hospital waste and sewage and the control of the antibiotic usage to prevent further environmental contamination.

Fecal carriage of multi-drug resistant and extended spectrum β-lactamases producing E. coli in household pigeons, Bangladesh

Antibiotic resistance and ESBL constitute a risk to human and animal health. Birds residing close to humans could mirror the spectrum of human associated antibiotic resistance. Household pigeons were screened in Bangladesh to shed light on human associated, as well as, environmental antibiotic resistance. Escherichia coli from pigeons (n=150) were tested against 11 antibiotics. 89% E. coli isolates were resistant to one or more critically important human antibiotics like ampicillin, cefadroxil, mecillinam, ciprofloxacin, gentamicin and tigecycline. No carbapenamase-producers were detected and the lower ESBL prevalence (5%) in pigeons. ESBL-producing E. coli isolates had blaCTX-M-15 genes. Pigeons shared some bacterial clones and had bird associated sequence types like E. coli ST1408. Fecal carriage of bacteria resistance of critically important human antibiotics, together with examples of shared genotypes among pigeons, indicate the human-birds and bird to bird transmissions are important in the epidemiology of antibiotic resistance.

Occurrence of Hybrid Escherichia coli Strains Carrying Shiga Toxin and Heat-Stable Toxin in Livestock of Bangladesh

Shiga toxin-producing Escherichia coli (STEC) and enterotoxigenic E. coli (ETEC) are important causes of diarrhea in humans and animals worldwide. Although ruminant animals are the main source of STEC, diarrhea due to this pathotype is very low in Bangladesh where ETEC remains the predominant group associated with childhood diarrhea. In the present study, E. coli strains (n = 35) isolated from Bangladesh livestock (goats, sheep, and cattle) and poultry (chicken and ducks) were analyzed for the presence of major virulence factors, such as Shiga toxins (STX-1 and STX-2), heat-labile toxin, and heat-stable toxins (STa and STb). Multiplex polymerase chain reaction results revealed 23 (66%) E. coli strains to be virulent possessing either sta (n = 5), stx (stx1, n = 8; stx2, n = 2), or both (n = 8) genes in varying combinations. Thirty-four percent (8/23) of strains from livestock were hybrid type that carried both stx (either stx1 or stx2) and ETEC-specific enterotoxin gene sta. Serotyping results revealed that the ETEC strains belonged to five serotypes, namely O36:H5, O174:H−, O152:H8, O109:H51, and O8:H21, while the STEC-producing strains belonged to serotypes O76:H19 (n = 3), O43:H2 (n = 2), O87:H16 (n = 2), OR:H2 (n = 1), O110:H16 (n = 1), and O152:H8 (n = 1). The STEC–ETEC hybrid strains belonged to serotypes O76:H19 (n = 3), O43:H2 (n = 2), O87:H16, OR:H2, and O152:H8. Forty percent (2/5) of the ETEC and 20% (2/10) of the STEC strains were multidrug resistant with the highest drug resistance (50%) being found in the hybrid strains. Molecular fingerprinting determined by pulsed-field gel electrophoresis and cluster analyses by dendrogram revealed that, genetically, STEC–ETEC hybrid strains were highly heterogeneous. Multidrug-resistant E. coli STEC–ETEC hybrid strains in domesticated animals pose a public health threat for humans in Bangladesh.

Handling and Welfare of Bovine Livestock at Local Abattoirs in Bangladesh

The World Organization for Animal Health (OIE) allows rope casting and the tying of legs for nonhuman animal slaughter without stunning. The handling and welfare of bovine livestock (Bos indicus and Bubalus bubalis) were studied in 8 local abattoirs in 5 districts of Bangladesh. A total of 302 animals were evaluated. At the local abattoirs, approximately 1/3 of the cattle and water buffalo were either emaciated or injured/sick. The size and vigor of the animals determined the casting method. Small and weak animals were cast on concrete floors by lifting a foreleg followed by pushing, or simply by twisting the head of the animal and then binding the legs with rope. Vigorous animals such as buffalo were cast using ropes and human force. Bleeding was slow and flaying was sometimes initiated before the animals were unconscious. Pulling and tearing of the trachea and pouring of water into the exposed trachea shortly after cutting were also observed in some cases. The overall animal handling was unnecessarily rough and the OIE standards were not implemented. Animals are subjected to considerable mistreatment, and there is an urgent need for the training and education of the staff in abattoirs concerning humane slaughtering practices as well as a need to build modern slaughtering plants in Bangladesh.