Introduction: Listeria monocytogenes is of major significance in human and veterinary medicine. Most human Listeria infections are foodborne and the association of contaminated milk and dairy produce consumption with human listeriosis is noteworthy. In Ethiopia, there is limited data regarding the prevalence of L. monocytogenes in raw bovine milk and dairy products. The aim of this study was, therefore, to determine the prevalence of L. monocytogenes in raw bovine milk and dairy produce. Methodology: A total of 443 milk and milk product samples were microbiologically analyzed following methods recommended by the U.S. Food and Drug Administration Bacteriological Analytical Manual to isolate Listeria spp. Results: The overall prevalence of Listeria spp. was 28.4% and specifically that of L. monocytogenes was 5.6%. Taking the prevalence of Listeria spp. into consideration, cheese was found to be highly contaminated at 60%, followed by pasteurized milk samples (40%), raw milk (18.9%) and yoghurt (5%). Considering the prevalence of Listeria monocytogenes only, raw milk had the lowest contamination while cheese had the highest, followed by pasteurized milk and yoghurt. Conclusions: Raw milk and milk products produced in urban and peri-urban areas of central Ethiopia were contaminated with pathogenic bacteria, L. monocytogenes. The detection of this pathogen in raw milk and milk products warrants an urgent regulatory mechanism to be put in place and also the potential role of milk processing plants in the contamination of dairy products should be investigated.

The treatment of invasive Escherichia coli infections is a challenge because of the emergence and rapid spread of multidrug resistant strains. Particular problems are those strains that produce extended spectrum β-lactamases (ESBL’s). Although the global characterization of these enzymes is advanced, knowledge of their molecular basis among clinical E. coli isolates in Ethiopia is extremely limited. This study intends to address this knowledge gap. The study combines antimicrobial resistance profiling and molecular epidemiology of ESBL genes among 204 E. coli clinical isolates collected from patient urine, blood, and pus at four geographically distinct health facilities in Ethiopia. All isolates exhibited multidrug resistance, with extensive resistance to ampicillin and first to fourth line generation cephalosporins and sulfamethoxazole-trimethoprim and ciprofloxacin. Extended spectrum β-lactamase genes were detected in 189 strains, and all but one were positive for CTX-Ms β-lactamases. Genes encoding for the group-1 CTX-Ms enzymes were most prolific, and CTX-M-15 was the most common ESBL identified. Group-9 CTX-Ms including CTX-M-14 and CTX-27 were detected only in 12 isolates and SHV ESBL types were identified in just 8 isolates. Bacterial typing revealed a high amount of strains associated with the B2 phylogenetic group. Crucially, the international high risk clones ST131 and ST410 were among the sequence types identified. This first time study revealed a high prevalence of CTX-M type ESBL’s circulating among E. coli clinical isolates in Ethiopia. Critically, they are associated with multidrug resistance phenotypes and high-risk clones first characterized in other parts of the world.

Introduction: Staphylococcal food intoxication is dependent on the production of enterotoxins, the single most important virulence factors. Various studies conducted in Ethiopia have depicted the prevalence of S. aureus in bovine milk. However, there is no published data regarding the enterotoxin gene profile of S. aureus isolates in Ethiopia. The aim of this study was, therefore, to evaluate enterotoxin gene carriage profile of S. aureus isolates recovered from bovine milk samples from central Ethiopia. Methodology: In this study, 109 S. aureus isolates recovered from bovine milk were analyzed for carriage of the classical enterotoxin genes. Genomic DNA extraction was performed using a commercially available kit. Two sets of multiplex polymerase chain reaction (PCR) assays were used to detect the five classical enterotoxin-coding genes and the toxic shock syndrome toxin gene. Results: At least one type of S. aureus enterotoxin gene (SE) was carried in 73 (66.9%) of the isolates. The most frequently encountered gene was sea (40; 36.7%) followed by seb (19; 17.4%), see (18; 16.5%), tst (16; 14.7%), sec-1 (12; 11.01%), and sed (7; 6.4%). Of the 73 S. aureus isolates harboring at least one of the enterotoxin genes, 26 (35.6%) strains harbored more than one enterotoxin gene. Conclusions: More than half of the S. aureus isolates harbored at least one of the enterotoxin coding genes, indicating milk specimens contaminated by S. aureus could have a high chance of causing food intoxication.

Antimicrobials have been playing an important role in preventing illness and death associated with infections due to bacteria. However, the emergence and spread of resistance by pathogens have decreased the effectiveness of the commonly prescribed antimicrobials. Intestinal Escherichia coli are among bacterial pathogens that are endowed with such resistance traits because they are important source and reservoir of genes that encode antimicrobial resistance. To determine the antimicrobial resistance profile of fecal isolates of E. coli from diarrheic patients. Stool samples were collected consecutively from 100 individuals who visited Selam Health Center during the study period, April to June 2018. Samples were collected and transported under sterile condition to the National Clinical Bacteriology and Mycology reference Laboratory, Ethiopian Public Health Institute. The samples were streaked on MacConkey agar and incubated overnight at 37°C. E. coli isolates were further confirmed using conventional biochemical tests. Antimicrobial susceptibility status was determined using the disk diffusion method on Mueller Hinton agar as recommended by the Clinical Laboratory Standard Institute. The raw data was compiled and entered to spreadsheet and analysis was done using SPSS Version 20 with p-value ≤0.05 considered statistically significant. Out of the 100 patients, 43 were female and the rest were male. Confirmed E. coli were isolated from 73 individuals. Antimicrobial susceptibility testing showed that E. coli isolated in this study were highly resistant to trimethoprim-sulfamethoxazole 49 (67.1%) and amoxicillin-clavulanic acid 47(64.4 %). No isolates showed resistance to gentamicin and tobramicin. Of all the isolates, 11(15.1%) were multidrug resistant. No association was observed between antimicrobial resistance status and sex of individuals included in this study. However, there was an association between age and resistance patterns. Resistance to commonly prescribed antibiotics among E. coli isolated in this study was high and a considerable proportions of the strains were multidrug resistant. This is an indication for an alarming rate of resistance of intestinal E. coli to first line antimicrobials. To reduce the problem, regular monitoring and education for the community are very important.

CTX-Ms are encoded by blaCTX-M genes and are widely distributed extended-spectrum β-lactamases (ESBLs). They are the most important antimicrobial resistance (AMR) mechanism to β-lactam antibiotics in the Enterobacteriaceae. However, the role of transmissible AMR plasmids in the dissemination of blaCTX-M genes has scarcely been studied in Africa where the burden of AMR is high and rapidly spreading. In this study, AMR plasmid transmissibility, replicon types and addiction systems were analysed in CTX-M-producing Escherichia coli clinical isolates in Ethiopia with a goal to provide molecular insight into mechanisms underlying such high prevalence and rapid dissemination. Of 100 CTX-Ms-producing isolates obtained from urine (84), pus (10) and blood (6) from four geographically distinct healthcare settings, 75% carried transmissible plasmids encoding for CTX-Ms, with CTX-M-15 being predominant (n = 51). Single IncF plasmids with the combination of F-FIA-FIB (n = 17) carried the bulk of blaCTX-M-15 genes. In addition, IncF plasmids were associated with multiple addiction systems, ISEcp1 and various resistance phenotypes for non-cephalosporin antibiotics. Moreover, IncF plasmid carriage is associated with the international pandemic E. coli ST131 lineage. Furthermore, several CTX-M encoding plasmids were associated with serum survival of the strains, but less so with biofilm formation. Hence, both horizontal gene transfer and clonal expansion may contribute to the rapid and widespread distribution of blaCTX-M genes among E. coli populations in Ethiopian clinical settings. This information is relevant for local epidemiology and surveillance, but also for global understanding of the successful dissemination of AMR gene carrying plasmids.