Colibacillosis, a disease caused by avian pathogenic Escherichia coli (APEC), can lead to great economic losses in the poultry industry. The aim of this study was to determine the prevalence of antibiotic resistance and antibiotic resistance patterns in APEC in Zimbabwe. From 503 chickens diagnosed with colibacillosis, 103 E. coli isolates were obtained. Isolation and identification of E. coli were carried out using microscopy and biochemical tests. The disc diffusion method was used to determine antibiotic susceptibility of the isolates to 8 commercial antibiotics. Many isolates exhibited resistance to more than one antibiotic. Antibiogram profiles indicated maximum resistance to tetracycline (100%), bacitracin (100%), and cloxacillin (100%) and a high prevalence of resistance to ampicillin (94.1%). However; there were high prevalences of sensitivity to ciprofloxacin (100%) and gentamycin (97.1%). The isolates showed moderate rates of sensitivity to chloramphenicol and neomycin. All isolates in this study showed multidrug resistance because they were all resistant to 3 or more antibiotics. Seven multidrug resistance patterns were observed. The most common pattern (resistance to ampicillin, bacitracin, cloxacillin, and tetracycline) was exhibited by 30 isolates. Our findings show that there is emerging drug resistance in APEC associated with colibacillosis in Zimbabwe. The observed high level of multidrug resistance could hamper the treatment of colibacillosis in Zimbabwe.

Colibacillosis, a disease caused by avian pathogenic Escherichia coli (APEC), is one of the main causes of economic losses in the poultry industry worldwide. This study was carried out in order to determine the APEC-associated virulence genes contained by E. coli isolates causing colibacillosis in chickens. A total of 45 E. coli isolates were obtained from the diagnostics and research branch of the Central Veterinary Laboratories, Bulawayo, Zimbabwe. These isolates were obtained from chickens with confirmed cases of colibacillosis after postmortem examination. The presence of the iutA, hlyF, ompT, frz, sitD, fimH, kpsM, sitA, sopB, uvrY, pstB and vat genes were investigated by multiplex polymerase chain reaction (PCR) assay. Of the 45 isolates, 93% were positive for the presence of at least one virulence gene. The three most prevalent virulence genes were iutA (80%), fimH (33.3%) and hlyF (24.4%). The kpsM, pstB and ompT genes had the lowest prevalence, having been detected in only 2.2% of the isolates. All 12 virulence genes studied were detected in the 45 APEC isolates. Virulence gene profiles were constructed for each APEC isolate from the multiplex data. The APEC isolates were profiled as 62.2% fitting profile A, 31.1% profile B and 6.7% profile C. None of the isolates had more than seven virulence genes. Virulence profiles of Zimbabwean APEC isolates are different from those previously reported. Zimbabwean APEC isolates appear to be less pathogenic and may rely on environmental factors and stress in hosts to establish infection.

Between January, 2013 and December, 2014, there was a lumpy skin disease (LSD) outbreak that affected cattle in different localities of Zimbabwe. The outbreak resulted in severe economic losses to the livestock industry. A retrospective study was conducted by examining stored veterinary records of the LSD outbreak at the Central Veterinary Laboratory (CVL) in Harare, Zimbabwe. Over the 2-year period, a total of 10,038 cases and 880 deaths (8.77 %) were recorded. LSD was reported from all regions of the country, with the highest incidence occurring in Mashonaland West (30.95 %) and Midlands province (14.59 %). The frequency of reported outbreaks was highest in March and April, with the lowest reported cases occurring in November. A total of 25 representative specimens (skin biopsies) were collected from nodular skin lesions of infected cattle, and after viral DNA isolation, the P32 gene was successfully amplified, by using PCR, in 88 % (22/25) of all assayed specimens. Out of the 22 samples that showed amplification, 16 (73 %) were selected for DNA sequencing, and from these, 13 sequences were submitted to GenBank and assigned accession numbers: KX033494, KX033495, KX033496, KX033497, KXO33498, KX033499, KX033500, KX033501, KX033502, KX033503, KX033504, KX033505 and KX033506. Phylogenetic analyses of the 13 sequences was done by using MEGA 7 and showed that the viruses formed two major clusters implying that at least two strains of LSDV are in circulation in Zimbabwe. This study provides the first report on the incidence and molecular characterisation of LSDV in Zimbabwe.

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There is limited information on the comparative genomic diversity of antibiotic-resistant Escherichia coli from wastewater. We sought to characterize environmental E. coli isolates belonging to various pathotypes obtained from a wastewater treatment plant (WWTP) and its receiving waters using whole-genome sequencing (WGS) and an array of bioinformatics tools to elucidate the resistomes, virulomes, mobilomes, clonality, and phylogenies. Twelve multidrug-resistant (MDR) diarrheagenic E. coli isolates were obtained from the final effluent of a WWTP, and the receiving river upstream and downstream of the WWTP were sequenced on an Illumina MiSeq machine. The multilocus sequence typing (MLST) analysis revealed that multiple sequence types (STs), the most common of which was ST69 (n = 4) and ST10 (n = 2), followed by singletons belonging to ST372, ST101, ST569, ST218, and ST200. One isolate was assigned to a novel ST ST11351. A total of 66.7% isolates were positive for β-lactamase genes with 58.3% harboring the blaTEM1B gene and a single isolate the blaCTX−M−14 and blaCTX−M−55 extended-spectrum β-lactamase (ESBL) genes. One isolate was positive for the mcr-9 mobilized colistin resistance gene. Most antibiotic resistance genes (ARGs) were associated with mobile genetic support: class 1 integrons (In22, In54, In191, and In369), insertion sequences (ISs), and/or transposons (Tn402 or Tn21). A total of 31 virulence genes were identified across the study isolates, including those responsible for adhesion (lpfA, iha, and aggR), immunity (air, gad, and iss), and toxins (senB, vat, astA, and sat). The virulence genes were mostly associated with IS (IS1, IS3, IS91, IS66, IS630, and IS481) or prophages. Co-resistance to heavy metal/biocide, antibiotics were evident in several isolates. The phylogenomic analysis with South African E. coli isolates from different sources (animals, birds, and humans) revealed that isolates from this study mostly clustered with clinical isolates. Phylogenetics linked with metadata revealed that isolates did not cluster according to source but according to ST. The occurrence of pathogenic and MDR isolates in the WWTP effluent and the associated river is a public health concern.