Antimicrobial Use and Resistance in Agriculture and Food Production Systems in Africa: A Systematic Review

In Africa, there is dearth of information on antimicrobial use (AMU) in agriculture and food production systems and its consequential resistance in pathogens that affect animal, human and environmental health. Data published between 1980 and 2021 on the magnitude of AMU and AMR in agriculture and food productions systems in Africa were reviewed. Data from 13-27 countries in Africa indicate that 3558-4279 tonnes of antimicrobials were used in animals from 2015 to 2019. Tetracyclines and polypeptides contributed the largest proportion of antimicrobials used. Cattle and poultry production account for the largest consumption of antimicrobials in Africa. Although limited studies have reported AMR in crops, fish and beekeeping, AMR from a variety of farm animals has been substantially documented in Africa. Some countries in Africa have developed policies/plans to address AMU and AMR in agriculture and food production systems; however, their enforcement is challenged by weak regulations. In conclusion, although there is limited information on the quantities of antimicrobials used in agriculture and food production system, the levels of AMR are high. There is a need to strengthen regulatory authorities with a capacity to monitor AMU in agriculture and food production systems in Africa.

Molecular Profiling of Class I Integron Gene in MDR Salmonella typhi Isolates

Typhoid fever is a paramount reason for horribleness that more mortal sin “around the sum ages aggregations clinched alongside iraq it initiated by salmonella typhi. Salmonella typhi is diagnosed serologically by the Widal test and confirmed by vitek and using polymerase chain reaction (PCR) based amplification of DNA from the bacterial samples of typhoid fever patients. The present study was designed to detect class I integron gene encoding antimicrobial of S. typhi using appropriate primers by PCR. These isolates of this study were collected from postgraduate laboratories (Prepared samples in vitro prepared diagnostics), they were a previous collected from carried out in Al Najaf provenance, throughout those period from July 2018 on March 2019 including 231 cases from blood, stool samples collected from patients suffering from typhoid fever were attended to Al-Sader Medical City and Al-Hakim General Hospital in Al-Najaf province. Biochemically tests and monovalent antisera gave 117 (50.64%) positive result S. typhi isolates and confirmed by Vitek system and PCR which showed positive result 59 (50.42%). Fifty nine isolates of S. typhi, were collected from patients with typhoid fever that distributed to 40/59 (34 %) from blood , 19/59 (15.1%) stool. Molecular detection revealed that most isolates of S. typhi were positive results to (intI) gene 43/59 isolate (the specific primer (intI) gene for S. typhi bacteria was designed in this study by using bioinformatics programs with NCBI website). According to the different diagnostic above, Vitek and PCR method were more sensitivity technique for S. typhi detection among typhoid patients. The results of virulence factors of S.typhi isolates were negative results for gelatinase, hemolysin, protease and capsulated. Multidrug resistance (MDR) of S. typhi isolates were represented by 18 antibiotics resistance to class and sub class of antibiotic. All S. typhi isolates appeared high resistance 100% to Aztreonam (AZM15), Nitrofurantion (F), Amoxicillin/clavulanicacid (AMC30), (PY25), Clarithromycin (CLR), Cefoxitin (FOX30), Penecillin(P10), Cefotaxime (CTX30), ampicillin (AMP), Meropenem (MEM), Tetracycline(TE30). Also resistance of isolates that revealed 91% to Impinem (IP ), 88% Ampicillin (AM10), 85%Amoxillin (AX), 81% Gentamicin (CN10), 80% Chloramphenicol (C30), 74% Cefpirome (CPR) and 68% Carbenicillin (CB).

Antibiotic Use in Agriculture and Its Consequential Resistance in Environmental Sources: Potential Public Health Implications

Due to the increased demand of animal protein in developing countries, intensive farming is instigated, which results in antibiotic residues in animal-derived products, and eventually, antibiotic resistance. Antibiotic resistance is of great public health concern because the antibiotic-resistant bacteria associated with the animals may be pathogenic to humans, easily transmitted to humans via food chains, and widely disseminated in the environment via animal wastes. These may cause complicated, untreatable, and prolonged infections in humans, leading to higher healthcare cost and sometimes death. In the said countries, antibiotic resistance is so complex and difficult, due to irrational use of antibiotics both in the clinical and agriculture settings, low socioeconomic status, poor sanitation and hygienic status, as well as that zoonotic bacterial pathogens are not regularly cultured, and their resistance to commonly used antibiotics are scarcely investigated (poor surveillance systems). The challenges that follow are of local, national, regional, and international dimensions, as there are no geographic boundaries to impede the spread of antibiotic resistance. In addition, the information assembled in this study through a thorough review of published findings, emphasized the presence of antibiotics in animal-derived products and the phenomenon of multidrug resistance in environmental samples. This therefore calls for strengthening of regulations that direct antibiotic manufacture, distribution, dispensing, and prescription, hence fostering antibiotic stewardship. Joint collaboration across the world with international bodies is needed to assist the developing countries to implement good surveillance of antibiotic use and antibiotic resistance.

Prevalence and characterization of Salmonella among humans in Ghana

Background

Non-typhoidal Salmonella (NTS) is a public health problem worldwide and particularly in Africa with high disease burden. This study characterized Salmonella isolates from humans in Ghana to determine serovar distribution, phage types, and antimicrobial resistance. Further, the clonal relatedness among isolates was determined.

Methods

One hundred and thirty-seven Salmonella isolates (111 clinical and 26 public toilet) were characterized using standard serotyping, phage typing, and antimicrobial susceptibility testing methods. The molecular epidemiology of common serovars (Salmonella Typhimurium and Salmonella Enteritidis) was established by pulsed field gel electrophoresis (PFGE).

Results

Twenty-two serovars were identified with S. Enteritidis, S. Typhimurium, and Salmonella Derby as the most dominant. One hundred and twelve isolates showed resistance to more than one antimicrobial. Fifty-eight (n = 58/112; 54.5%) strains were multi-resistant with low resistance to cephalosporins ceftazidime (8.0%), cefotaxime (4.5%), and cefoxitin (2.7%) with synergy to clavulanic acid indicating possible ESBLs. Isolates showed high resistance to trimethoprim (66.1%), tetracycline (61.6%), ampicillin (57.1%), sulfamethoxazole (46.4%), chloramphenicol (33.9%), and ciprofloxacin (25.0%). The most common resistance pattern of multi-resistant serovars was to ampicillin, chloramphenicol, sulphonamide, and trimethoprim. S. Enteritidis (18/43) strains reacted with typing phages but did not conform to any phage type with PT14B and PT4 as predominant definitive phage types. Six S. Typhimurium strains reacted but did not conform to any recognized phage type while seven were non-typable. The predominant definitive phage types were DT1 and DT22. PFGE patterns of human S. Enteritidis were closely related to patterns of poultry isolates obtained in a previous study in Ghana.

Conclusions

Cephalosporin resistance is uncommon among Salmonella from humans in Ghana. Poultry may be an important source of human salmonellosis. There is an urgent need for the implementation of routine surveillance of antimicrobial use and bacterial resistance among humans in Ghana.

Salmonella species in piglets and weaners from Uganda: prevalence, antimicrobial resistance and herd-level risk factors

Non-typhoidal salmonellosis is of concern in humans in sub-Saharan Africa, and this is partly due to the high number of immunocompromised persons. Pork and pork products could be among the sources of these non-typhi Salmonella spp. The aim of this study was to identify Salmonella spp. in piglets and weaners in northern and eastern Uganda, characterize their antimicrobial resistance patterns and determine herd-level risk factors. Fecal samples were collected from 465 piglets and weaners from 93 herds (49 and 44 from northern and eastern Uganda, respectively). In addition, information about the herd management and potential risk factors were collected. The fecal samples were cultured for the identification of Salmonella spp. The Salmonella spp. confirmed by serotyping were further characterized by determination of minimum inhibitory concentration (MIC) to 12 antimicrobials by broth microdilution. At individual level, the total prevalence of Salmonella spp. was 12% (12.2% in northern and 11.9% in eastern Uganda). At herd level, the total prevalence was 39% (43% in northern and 34% in eastern Uganda). From 56 samples with Salmonella spp., 20 serovars were identified including two serovars identified only by their antigenic formulae. The predominant serovars were S. Zanzibar, S. Heidelberg, S. Infantis, S. Typhimurium, S. Stanleyville, S. Aberdeen and S. Kampala. In total, 57% of the 53 Salmonella spp. analyzed, originating from 27% of the herds, were resistant to at least one antimicrobial agent. The majority of drug-resistant isolates (60%) were from northern Uganda. Eight multidrug-resistant (MDR) isolates were from northern Uganda and three MDR isolates were from eastern Uganda. Increased prevalence of Salmonella spp. was associated with feeding the young and adults separately as compared to feeding the young and adults together (p=0.043, OR=4.3; 95% CI 1.1, 17.38). Protective factors were "intensive" method of keeping the pigs versus "tethering and roaming" (p=0.016, OR=0.11; 95% CI 0.02, 0.64), "intensive" method versus "semi-intensive" method (p=0.048, OR=0.12; 95% CI 0.01, 0.96) and cleaning feeders after every two days versus daily (p=0.017, OR=0.18; 95% CI 0.05, 0.72). This study has revealed a high prevalence of infection of piglets and weaners with diverse non-typhi Salmonella serovars and highlights the potential role of pork and pork products as sources of these organisms for humans. In addition, this study has identified protective factors that could be promoted to control Salmonella spp. and in antimicrobial resistance reduction programs in rural pigs from Uganda.