Effect of veterinary feed directive rule changes on tetracycline-resistant and erythromycin-resistant bacteria (Salmonella, Escherichia, and Campylobacter) in retail meats in the United States.

BACKGROUND: Antimicrobial-resistant bacteria are a growing public health threat. In 2017 the U.S. Food and Drug Administration implemented Veterinary Feed Directive (VFD) rules changes to limit medically important antimicrobial use in food-producing animals, combating antimicrobial-resistant bacteria. The effect of the VFD rule changes on the occurrence of bacteria resistant to medically-important antimicrobials in retail meats is yet to be investigated in the U.S. This study investigates whether the VFD rule changes affected the occurrence of tetracycline-resistant and erythromycin-resistant bacteria (Salmonella, Escherichia, and Campylobacter) in retail meats in the U.S. METHODS: Multivariable mixed effect logistic regression models were used to analyze 2002-2019 retail meats surveillance data from the National Antimicrobial Resistance Monitoring System (NARMS) in the U.S. Variables included VFD rule changes, meat type, quarter of year, and raising claims. A potential association between these variables and the occurrence of tetracycline-resistant and erythromycin-resistant bacteria (Salmonella, Escherichia, and Campylobacter) in retail meats was estimated. RESULTS: Analysis included data regarding tetracycline-resistant Salmonella (n = 8,501), Escherichia (n = 20, 283), Campylobacter (n = 9,682), and erythromycin-resistant Campylobacter (n = 10,446) in retail meats. The odds of detecting tetracycline-resistant Escherichia (OR = 0.60), Campylobacter (OR = 0.89), and erythromycin-resistant Campylobacter (OR = 0.43) in chicken breast significantly decreased after the VFD rule changes, compared to the pre-VFD rule change period. The odds of detecting tetracycline-resistant Salmonella (0.66), Escherichia (OR = 0.56), and Campylobacter (OR = 0.33) in ground turkey also significantly decreased. However, the odds of detecting tetracycline-resistant Salmonella (OR = 1.49) in chicken breast and erythromycin-resistant Campylobacter (OR = 4.63) in ground turkey significantly increased. There was no significant change in the odds of detecting tetracycline-resistant Salmonella and Escherichia in ground beef or pork chops. CONCLUSIONS: The implementation of VFD rule changes had a beneficial effect by reducing the occurrence of tetracycline-resistant and erythromycin-resistant bacteria in chicken and ground turkey. Ongoing surveillance of antimicrobial resistance and antimicrobial use could complement the implementation of stewardship such as VFD rule in food-producing animals in the U.S.

Occurrence of tuberculosis among people exposed to cattle in Bangladesh.

BACKGROUND: Tuberculosis (TB) has been an important public health concern in Bangladesh. The most common cause of human TB is Mycobacterium tuberculosis, while bovine TB is caused by Mycobacterium bovis. OBJECTIVE: The objective of this study was to determine the frequency of TB in individuals with occupational exposure to cattle and to detect Mycobacterium bovis among cattle in slaughterhouses in Bangladesh. METHODS: Between August 2014 and September 2015, an observational study was conducted in two government chest disease hospitals, one cattle market, and two slaughterhouses. [Correction added on 27 June 2023, after first online publication: In the preceding sentence, the year "2014" has been added after the word "August".] Sputum samples were collected from individuals who met the criteria for suspected TB and had been exposed to cattle. Tissue samples were collected from cattle that had low body condition score(s). Both humans and cattle samples were screened for acid-fast bacilli (AFB) by Ziehl-Neelsen (Z-N) staining and cultured for Mycobacterium tuberculosis complex (MTC). Region of difference (RD) 9-based polymerase chain reaction (PCR) was also performed to identify Mycobacterium spp. We also conducted Spoligotyping to identify the specific strain of Mycobacterium spp. RESULTS: Sputum was collected from a total of 412 humans. The median age of human participants was 35 (IQR: 25-50) years. Twenty-five (6%) human sputum specimens were positive for AFB, and 44 (11%) were positive for MTC by subsequent culture. All (N = 44) culture-positive isolates were confirmed as Mycobacterium tuberculosis by RD9 PCR. Besides, 10% of cattle workers were infected with Mycobacterium tuberculosis in the cattle market. Of all TB (caused by Mycobacterium tuberculosis) infected individuals, 6.8% of individuals were resistant to one or two anti-TB drugs. The majority of the sampled cattle (67%) were indigenous breeds. No Mycobacterium bovis was detected in cattle. CONCLUSIONS: We did not detect any TB cases caused by Mycobacterium bovis in humans during the study. However, we detected TB cases caused by Mycobacterium tuberculosis in all humans, including cattle market workers.

Tetracycline, Sulfonamide, and Erythromycin Residues in Beef, Eggs, and Honey Sold as "Antibiotic-Free" Products in East Tennessee (USA) Farmers' Markets.

Foods that contain antibiotic residues have potential adverse health effects on consumers and provide selective pressure for the threat of antimicrobial resistance (AMR). This study's objective was to measure tetracycline, sulfonamide, and erythromycin residues in beef, eggs, and honey sold as "antibiotic-free" at farmers' markets in East Tennessee (East TN) in the United States (U.S.). Between July and September 2020, 36 "antibiotic-free" food products (9 beef, 18 egg, and 9 honey products) were purchased from East TN farmers' markets and tested for tetracycline, sulfonamide, and erythromycin residues using competitive enzyme-linked immunosorbent assays (cELISA). All beef, egg, and honey products had tetracycline residue; the median concentrations were 51.75, 30.25, and 77.86 µg/kg, respectively. Sulfonamide residue was present in every sample of beef. Of 18 eggs, 11 eggs had detectable sulfonamide residue; the median concentrations were 3.50 and 1.22 µg/kg in beef and eggs, respectively. Each sample of beef and honey contained erythromycin residue; the median concentrations were 3.67 and 0.68 µg/kg, respectively. Overall, the median concentrations of tetracycline, sulfonamide, and erythromycin residues were below the maximum residue levels (MRLs) set in the U.S. for beef and eggs. Thus, the beef and eggs sold as "antibiotic-free" in East TN farmers' markets can be considered safe for consumption. Safety determination for honey could not be made because MRLs have not been set for honey in the U.S. Because these residues should not be expected in "antibiotic-free" food products, it is important to further investigate the potential sources of these residues in these products.

Effect of Changes in Veterinary Feed Directive Regulations on Violative Antibiotic Residues in the Tissue of Food Animals from the Inspector-Generated Sampling in the United States.

The presence of antibiotic residues in the tissue of food animals is a growing concern due to the adverse health effects that they can cause in humans, such as antibiotic resistance bacteria. An inspector-generated sampling (IGS) dataset from the United States National Residue Surveillance Program, collected between 2014 and 2019, was analyzed to investigate the association of changes in the veterinary feed directive (VFD) regulations on the detection of violative penicillin, tetracycline, sulfonamide, desfuroylceftiofur, tilmicosin, and florfenicol, residues in the tissue of food animals. Multivariable logistic regression models were used for analysis. While the animal production class was significantly associated with residue violations for tetracycline, having a sample collection date after the implementation of change in VFD regulations was not. However, the odds of detecting violative sulfonamide and penicillin residues in the tissue of food animals following the implementation of the change in VFD regulations were 36% and 24% lower than those collected before the implementation of the change in VFD regulations period, respectively, irrespective of animal production class. Violative desfuroylceftiofur, tilmicosin, and florfenicol residues in the tissue of food animals were not significantly associated with the implementation of changes in the VFD regulations. Further investigation of the factors that influence the presence of violative antibiotic residues in the tissue of food animals following the change in VFD regulations would lend clarity to this critical issue.

Outbreak of diarrhoea in piglets caused by novel rotavirus genotype G4P[49] in north-western district of Bangladesh, February 2014.

Group A rotavirus (RVA) associated diarrhoea in piglets represents one of the major causes of morbidity and mortality in pig farms worldwide. A diarrhoea outbreak occurred among nomadic piglets in north-western district of Bangladesh in February 2014. Outbreak investigation was performed to identify the cause, epidemiologic and clinical features of the outbreak. Rectal swabs and clinical information were collected from diarrhoeic piglets (n = 36). Rectal swabs were tested for RVA RNA by real-time reverse transcription polymerase chain reaction (rRT-PCR) using NSP3-specific primers. The G (VP7) and P (VP4) genes were typed by conventional RT-PCR and sanger sequencing and full genome sequences were determined using next-generation sequencing. We found the attack rate was 61% (50/82) among piglets in the nomadic pig herd, and the case fatality rate was 20% (10/50) among piglets with diarrhoea. All study piglets cases had watery diarrhoea, lack of appetite or reluctance to move. A novel RVA strain with a new P[49] genotype combined with G4 was identified among all piglets with diarrhoea. The genome constellation of the novel RVA strains was determined to be G4-P[49]-I1-R1-C1-M1-A8-N1-T7-E1-H1. Genetic analysis shows that the novel G4P[49] strain is similar to Indian and Chinese porcine or porcine-like G4 human strains and is genetically distant from Bangladeshi human G4 strains. Identification of this novel RVA strain warrants further exploration for disease severity and zoonotic potential.

An outbreak of classical swine fever in pigs in Bangladesh, 2015.

In a group of 22 healthy pigs aged between 4 and 6 months, 2 pigs became ill with high fever, complete anorexia, cough and abnormal swaying movements on 22 June 2015. One of them died on June 24 and the second died on July 3. Shortly after, the remaining pigs also fell ill and died from the same illness by 10 August 2015. We investigated the aetiology, epidemiological and clinical features of the outbreak. We recorded the clinical signs and symptoms for each pig with the date of onset of illness. Veterinarians conducted post-mortem examinations on the 12 dead pigs, they collected tissue samples from the dead pigs and placed them in a tube containing 1 mL of nucleic acid extraction buffer (lysis buffer). We tested all the tissue samples by real-time reverse transcription polymerase chain reaction (rRT-PCR) to detect classical swine fever virus (CSFV) because the animals' symptoms matched those of this disease. We also conducted a phylogentic analysis of the nucleotide sequence of the E2 gene segment of CSFV detected in a lung tissue sample. The attack rate (22/22) and the case fatality were 100%. The predominant symptoms of the disease included high fever, cough, diarrhoea and swaying movements of the hind legs prior to death. Of the 12 pigs tissue samples tested, all had evidence of the presence of CSFV RNA by rRT-PCR. The phylogenetic analysis indicated that the virus belongs to genotype 2.2, which is closely related to CSFV genotype 2.2 reported in India. Our investigation suggests that CSF is circulating in pigs, posing a risk for communities in Bangladesh that rely on pigs for economic income and dietary protein. Future research could focus on estimating the disease and economic burden of CSFV in pig rearing areas to determine if interventions might be warranted or cost-effective.

An epidemiological study of avian influenza A (H5) virus in nomadic ducks and their raising practices in northeastern Bangladesh, 2011-2012.

BACKGROUND: In Bangladesh, nomadic duck flocks are groups of domestic ducks reared for egg production that are moved to access feeding sites beyond their owners' village boundaries and are housed overnight in portable enclosures in scavenging areas. The objectives of this study were to measure the prevalence of influenza A virus RNA and H5-specific antibodies in nomadic ducks and to characterize nomadic duck raising practices in northeastern Bangladesh. METHODS: We tested duck egg yolk specimens by competitive ELISA to detect antibodies against avian influenza A (H5) and environmental fecal samples by real-time reverse-transcription polymerase chain reaction (rRT-PCR) to detect influenza A virus RNA and H5 subtype. RESULTS: The median age of the ducks was 24 months (range: 8-36 months) and the median flock size was 300 ducks (range: 105-1100). Of 1860 egg yolk samples, 556 (30%, 95% confidence interval (CI): 28-32) were positive for antibodies against H5 and 58 flocks (94%) had at least one egg with H5-specific antibodies. Of 496 fecal samples, 121 (24%, 95% CI: 22-29) had detectable influenza A RNA. Thirty-three flocks (53%) had at least one fecal sample positive for influenza A RNA. CONCLUSIONS: Nomadic ducks in Bangladesh are commonly infected with avian influenza A (H5) virus and may serve as a bridging host for transmission of avian influenza A (H5) virus or other avian influenza A viruses subtypes between wild waterfowl, backyard poultry, and humans in Bangladesh.

Influenza B virus outbreak at a religious residential school for boys in Northern Bangladesh, 2011.

BACKGROUND: National media reported a febrile illness among dormitory residents of a boys' religious school. We investigated the outbreak to identify cause. METHODS: Individuals with fever (>100°F) and cough or sore throat between 1 and 13 August 2011 were influenza-like-illness (ILI) case-patients. We collected histories and specimens from hospitalized case-patients and visited campus to explore environmental context. RESULTS: All 28 case-patients were dormitory residents including 27 hospitalizations. Accommodation space per resident was <0.8 square metres. Nasal and oropharyngeal swabs from 22 case-patients were positive for influenza B virus using real-time reverse transcription polymerase chain reaction (rRT-PCR). CONCLUSIONS: Overcrowding likely facilitated transmission leading to this dormitory outbreak.