Vibrio cholerae O1 and Escherichia coli O157:H7 from drinking water and wastewater in Addis Ababa, Ethiopia.

BACKGROUND: In Addis Ababa, Ethiopia, open ditches along innner roads in residential areas serve to convey domestic wastewater and rainwater away from residences. Contamination of drinking water by wastewater through faulty distribution lines could expose households to waterborne illnesses. This prompted the study to assess the microbiological safety of wastewater and drinking water in Addis Ababa, identify the pathogens therein, and determine their antibiotic resistance patterns. RESULTS VIBRIO CHOLERAE: O1, mainly Hikojima serotype, was isolated from 23 wastewater and 16 drinking water samples. Similarly, 19 wastewater and 10 drinking water samples yielded Escherichia coli O157:H7. V. cholerae O1 were 100% resistant to the penicillins (Amoxacillin and Ampicillin), and 51-82% were resistant to the cephalosporins. About 44% of the V. cholerae O1 isolates in this study were Extended Spectrum Beta-Lactamase (ESBL) producers. Moreover, 26% were resistant to Meropenem. Peperacillin/Tazobactam was the only effective ß-lactam antibiotic against V. cholerae O1. V. cholerae O1 isolates showed 37 different patterns of multiple resistance ranging from a minimum of three to a maximum of ten antimicrobials. Of the E. coli O157:H7 isolates, 71% were ESBL producers. About 96% were resistant to Ampicillin. Amikacin and Gentamicin were very effective against E. coli O157:H7 isolates. The isolates from wastewater and drinking water showed multiple antibiotic resistance against three to eight antibiotic drugs. CONCLUSIONS: Open ditches for wastewater conveyance along innner roads in residence areas and underground faulty municipal water distribution lines could be possible sources for V. cholerae O1 and E. coli O157:H7 infections to surrounding households and for dissemination of multiple drug resistance in humans and, potentially, the environment.

Escherichia coli isolates from vegetable farms in Addis Ababa, Ethiopia: Antimicrobial susceptibility profile and associated resistance genetic markers.

The use of animal manure to fertilize soil is an emerging concern contributing to the transfer of antimicrobial-resistant pathogens to vegetables. Hence, assessing antimicrobial susceptibility profile of Escherichia coli in vegetable farms is essential to design appropriate interventions against antimicrobial resistance (AMR) in the food chain. This study assessed antimicrobial resistance profile and associated genetic markers among E. coli isolated from vegetable farms fertilized with animal manure in Addis Ababa, Ethiopia. A total of 1044 samples were collected using convenience sampling: soil (n = 271), manure (n = 375), and vegetables (n = 398) from 81 vegetable farms in Addis Ababa, Ethiopia. Antimicrobial susceptibility test was conducted for 100 E. coli isolates and antimicrobial resistance genes (ARGs) were tested by polymerase chain reaction (PCR). Of the 1044 collected samples, 25.3% were positive for E. coli, with significantly higher prevalence in the manure sample and samples collected from Akaki Kality sub-city (p < .05). The highest resistance rate was recorded for tetracycline (72%), followed by streptomycin (63%), and sulfamethoxazole +trimethoprim (56%). Multidrug resistance was detected in 61% of the E. coli isolates. The aac(3)-IV (76.9%), bla TEM (65.4%), aadA (60.3%), tet(A) (58.3%), and sulI (51.7%) were the commonly detected resistance genes. The current study showed a high burden of antimicrobial resistance among E. coli isolated from manure-amended vegetable farms, with potential of playing a significant role in the dissemination of antimicrobial resistance in the food chain. Efforts should be made to reduce the burden of resistant organisms and ARGs through prudent use of antimicrobials in livestock and application of appropriate composting techniques before using manure as fertilizer.

Prevalence and Antimicrobial Susceptibility Profile of Salmonella from Poultry Farms and In-Contact Humans and Associated Risk Factors in Addis Ababa, Ethiopia.

Poultry and poultry products are the common sources of Salmonella,which is one of the serious food-borne bacterial diseases in humans. Little is known about the status of Salmonella and their antimicrobial susceptibility in poultry farms in Addis Ababa. This study was conducted to estimate the prevalence and antimicrobial susceptibility of Salmonella isolates and to investigate possible risk factors for the occurrence of Salmonella in poultry farms in Addis Ababa. We recruited 58 poultry farms, from which 471 poultry-related samples and 44 stool samples from in-contact humans were collected. The isolates were tested for their susceptibility to 11 antimicrobials using the Kirby-Bauer disk diffusion assay. The farm-level prevalence of Salmonella was 36.2% and the sample-level prevalence was 6.4% for samples taken from poultry farms and 4.5% in human stool samples who have contact with poultry. On-farm waste disposal practices and chicken being purchased from different multiplication farms were significantly associated with Salmonella positivity of the farms (p < 0.05). Eleven (34.4%) Salmonella isolates were resistant to streptomycin, and nine (28.1%) were resistant to tetracycline. Thirteen (40.6%) Salmonella isolates were resistant to two or more antimicrobials tested in this study, whereas resistance to 3 or more antimicrobials was detected in seven (21.9%) isolates. In conclusion, a high prevalence of Salmonella and a high rate of resistance to multiple antimicrobials were detected in poultry farms in Addis Ababa. Hence, implementation of strong biosecurity measures and rational use of antimicrobials are recommended.

Antibiogram of Escherichia coli Isolated from Dairy Cattle and in-Contact Humans in Selected Areas of Central Ethiopia.

Background: Antimicrobial resistance (AMR) is a global threat to public and animal health. Escherichia coli is considered an indicator organism for monitoring AMR among gram-negative Enterobacteriaceae in humans and animals. The current study aims to assess the antibiogram profile of E. coli isolated from dairy cattle and in-contact humans in central Ethiopia and to identify risk factors associated with multidrug resistance (MDR). Methods: A cross-sectional study was conducted in which 58 farms were recruited from selected districts of central Ethiopia. E. coli was isolated using standard bacteriological techniques. A total of 200 representative isolates (140 from cattle and 60 from humans in contact) were randomly selected and tested for susceptibility to a panel of 13 antimicrobials using the Kirby-Bauer disc diffusion assay. Results: The highest rate of resistance was observed for sulfamethoxazole+trimethoprim (58.6%, 82/140) and amoxicillin+clavulanic acid (70.0%, 42/60) among E. coli isolates from cattle and hmans, respectively. In contrast, resistance rates in isolates from in contact humans with the cattle were 30%, 33.3%, and 66.7%, respectively. Resistance to tetracycline (p=0.02), streptomycin (p=0.03), and sulfamethoxazole+trimethoprim (p=0.007) was significantly high in E. coli isolated from cattle on commercial dairy farms than in those isolated from cattle on smallholder farms. There was no significant difference (p>0.05) in the rate of resistance between E. coli isolated from in contact humans with smallholder and commercial dairy farms. Antimicrobial use for treatment purpose (p=0.04) and non-compliance with the drug withdrawal period (p=0.03) were significantly associated with the farm-level occurrence of MDR. Conclusion: A high rate of resistance was detected in E. coli isolated from the feces of dairy cattle and in-contact humans. This necessitates an effective intervention through a one-health approach and further molecular studies are required to establish source attribution.

Antimicrobial Susceptibility and Characterization of Extended-Spectrum ß-Lactamase-Producing Escherichia coli Isolated from Stools of Primary Healthcare Patients in Ethiopia.

Antimicrobial resistance of Escherichia coli is a growing problem in both developed and developing countries. This study aimed to investigate the phenotypic antimicrobial resistance of E. coli isolates (n = 260) isolated from the stool specimen of patients attending public health facilities in Addis Ababa and Hossana. This study also aimed to characterize phenotypically confirmed extended-spectrum beta-lactamase (ESBL)-producing E. coli isolates (n = 22) using whole-genome sequencing. Resistance to 18 different antimicrobials was assessed using the disc diffusion method according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. The highest resistance rate among the E. coli isolates was found for ampicillin (52.7%), followed by trimethoprim-sulfamethoxazole (29.6%). Of all isolates, 50 (19.2%) were multidrug-resistant and 22 (8.5%) were ESBL producers. ESBL genes were detected in 94.7% of the sequenced E. coli isolates, and multiple ß-lactamase genes were detected in 57.9% of the isolates. The predominant ESBL gene identified was blaCTX-M-15 (78.9%). The blaTEM-1B gene was detected in combination with other ESBL genes in 57.9% of the isolates, while only one of the sequenced isolates contained the blaTEM-1B gene alone. The blaCTX-M-3 gene was detected in three isolates. The genes blaCTX-M-15 and blaTEM-1B as well as blaCTX-M-15 and blaTEM-169 were confirmed to coexist in 52.6% and 10.5% of the sequenced E. coli isolates, respectively. In addition, blaOXA-1 was identified together with blaCTX-M-15 and blaTEM-1B in one isolate, and in one isolate, blaTEM-169 together with blaCTX-M-15 and blaTEM-1B was found. The results obtained show that measures need to be taken to reduce the spread of drug resistance and ensure the long-term use of available antimicrobials.

Prevalence and Antimicrobial Susceptibility Profile of Salmonella and Shigella among Diarrheic Patients Attending Selected Health Facilities in Addis Ababa, Ethiopia.

Diarrhea is one of the important public health problems in developing countries. Salmonella and Shigella species are the major bacterial causal agents of diarrhea. The increasing burden of antimicrobial resistance is posing difficulty in the treatment of these pathogens. This study aimed to assess the occurrence of Salmonella and Shigella in the feces of diarrheic patients receiving health services in Addis Ababa, Ethiopia, and to determine their antimicrobial susceptibility profile. A cross-sectional study involving 13 health centers was conducted where 428 diarrheic patients were recruited. Standard microbiology techniques were used to isolate Salmonella and Shigella from stool samples. In addition, Salmonella isolates were confirmed by polymerase chain reaction (PCR). The Kirby-Bauer disc diffusion method was employed to assess susceptibility to 11 antimicrobials for each of the Salmonella and Shigella isolates. The prevalence of Salmonella and Shigella spp. among diarrheic patients was 8.4%; n = 36 and 5.6%; n = 24, respectively. Thirty (83.3%) of Salmonella isolates were susceptible to all antimicrobials tested, whereas 4 (10.8%) of isolates were resistant to 2 or more antimicrobials and 2 (5.6%) were multidrug resistant. Resistance to ampicillin was recorded in only one (2.7%) of Salmonella isolates; however, resistance to ampicillin was recorded in 12 (50%) of the Shigella isolates. Half of the Shigella isolates (n = 12) were resistant to 2 or more antimicrobials while 5 (20.8%) of them were resistant to 3 or more antimicrobials. The overall rate of resistance to antimicrobials was more common in Shigella compared to Salmonella isolates. In conclusion, Salmonella and Shigella were isolated from the feces of diarrheic patients, with a higher rate of antimicrobial resistance in Shigella isolates, which could make the treatment of shigellosis challenging. Therefore, increasing hygienic practices during food preparation to reduce the burden of Salmonella and Shigella infection and prudent use of antimicrobials are recommended to limit the spread of antimicrobial resistant strains.

Antidiarrheal and Antibacterial Activities of Calpurnia aurea: Benth Seed Different Extracts.

Background: Calpurnia aurea is believed to have antidiarrheal potential but with limited scientific evidence. This study aimed investigating antidiarrheal and antibacterial activity of aqueous and 80% methanol seed extracts of the plant in mice and selected diarrhea-causing bacterial strains, respectively. Methods: Castor oil-induced diarrhea, prostaglandin-induced enteropooling, and castor oil-induced charcoal meal test models in mice of either sex using three dose levels (60, 120, and 240 mg/kg) were applied to evaluate antidiarrheal activity. Parameters, including onset, number, wet stool weight, weight and volume of secretion, and intestinal motility, were taken into consideration. The antibacterial activity was assessed on Shigella soni, Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa using disk diffusion and microdilution techniques. Results: Compared to controls, pretreatment of mice at the graded dose (60, 120, and 240 mg/kg) resulted in a significant (p < 0.05) drop in frequency of wet stools and watery content of diarrhea as well as in delaying onset of diarrhea. Both extracts exhibited inhibition of diarrhea in a dose-dependent manner in all models used. The extracts also showed significant (p < 0.05) reduction in intestinal motility in castor oil-induced models. Both extracts showed a marginal activity against the selected bacterial strains; a better effect was seen with 80% methanol seed extract. Conclusion: Both extracts of the plant have beneficial effect in controlling diarrhea. This finding supports the use of the plant as a traditional antidiarrheal remedy.

Nontyphoidal Salmonella and Their Antimicrobial Susceptibility among Diarrheic Patients Attending Private Hospitals in Addis Ababa, Ethiopia.

Nontyphoidal Salmonella (NTS) is one of the major causes of bacterial foodborne infection. It is mainly manifested by self-limiting gastroenteritis in healthy individuals but can also cause severe complications including blood stream infection and mortality. The emergence of multidrug-resistant strains of Salmonella is becoming a global public health concern. This study is aimed at estimating the prevalence of Salmonella, identifying serotypes involved, and investigating antimicrobial susceptibility of the isolates among diarrheic patients attending private hospitals in Addis Ababa. We collected a total of 298 stool samples from diarrheic patients attending five private hospitals in Addis Ababa and isolated Salmonella according to standard microbiological techniques; the isolates were serotyped using slide agglutination and microplate agglutination techniques. Antimicrobial susceptibility test of the isolates was carried out using Kirby-Bauer disc diffusion assay according to Clinical Laboratory Standards Institute guidelines. Fourteen stool samples (4.7%) were positive for Salmonella, and Salmonella Kiambu was the most dominant serovar (n = 7, 50%) followed by S. Saintpaul (n = 4, 28.6%) and S. Haifa (n = 2, 14.3%). Three (21.4%) of the isolates were resistant to sulfisoxazole and tetracycline each and 2 (14.3%) to ampicillin. Resistance to two antimicrobials was detected only in 2 (14.3%) of the isolates, and none of the isolates were resistant to more than two antimicrobials. In conclusion, the current study showed low prevalence of NTS in diarrheic patients attending private hospitals in Addis Ababa. Although multidrug resistance to several antimicrobials was not detected in the isolates, prudent use of antimicrobials is recommended to guaranty the long-term use of the available antimicrobials.

Asymptomatic Bacteriuria among Pregnant Women in Addis Ababa, Ethiopia: Prevalence, Causal Agents, and Their Antimicrobial Susceptibility.

Asymptomatic bacteriuria (ASBU) is an important health problem among pregnant women, particularly in low-income countries. This study aimed to estimate the prevalence of ASBU and potential risk factors among pregnant women attending antenatal care centers in Addis Ababa. It also aimed to identify causal bacterial pathogens and to assess their antimicrobial susceptibility. A health facility-based cross-sectional study was conducted from March to June 2019. Urine samples from a total of 281 pregnant women with no symptoms of urinary tract infection were tested for ASBU. Women whose urine samples carried greater than or equal to 105 colony-forming units (CFU) of bacteria per milliliter of urine when grown on plate count agar were considered positive for ASBU. Bacterial pathogens were isolated from urine samples of women with ASBU using standard microbiological techniques. Antimicrobial susceptibility of isolates was investigated using the Kirby-Bauer disk diffusion method on Muller-Hinton agar plates. Of 281 pregnant women examined, 44 (15.7%) were positive for ASBU. Logistic regression analysis of the putative risk factors tested in the current study showed that none of them were significantly associated with the occurrence of ASBU (p > 0.05). The most frequently isolated bacterial species were Escherichia coli 17 (30.2%), Proteus 13 (23.2%), and Enterococcus 11 (19.6%). All of the E. coli, Citrobacter, and Klebsiella isolates and 84.6% of Proteus were resistant to ampicillin. All bacterial isolates were resistant to at least one of the antimicrobials tested. Resistance to three or more antimicrobials was detected in 15 (88.2%) of E. coli, 13 (100%) of Proteus, and 8 (72.7%) of Enterococcus isolates. Resistance to as many as 7 antimicrobials among E. coli, 8 antimicrobials among Proteus, and 7 antimicrobials among Enterococcus isolates was recorded. Detection of ASBU in a substantial number of pregnant women in this study warrants the need for a detailed study on possible risks of developing symptomatic urinary tract infection (UTI) and associated complications. Multidrug resistance to several antimicrobials was observed in the majority of bacterial isolates. Regular assessment of antimicrobial susceptibility of uropathogens to commonly prescribed antimicrobials and implementation of prudent use of antimicrobials are recommended.

Maternal Complications and Adverse Pregnancy Outcomes among Pregnant Women who Acquired Asymptomatic Bacteriuria in Addis Ababa, Ethiopia.

In this study, we aimed to document adverse pregnancy outcomes and maternal complications among pregnant women who acquired asymptomatic bacteriuria in Addis Ababa, Ethiopia. We used hospital-based prospective cohort study design in which we followed 44 pregnant women with asymptomatic bacteriuria confirmed by urine culture result of ≥105cfu/ml of urine. We documented adverse pregnancy outcomes and maternal complications in terms of frequency, percentage, mean, and standard deviation. Additionally, we used Pearson's correlation coefficient to investigate associations of selected variables with perinatal death as one of adverse pregnancy outcomes. Of the 44 pregnant women enrolled in the study, complete data was collected from 43 participants with one lost to follow-up. Six (14%) of women developed fever and were treated with antibiotic during pregnancy, 26 (60.5%) delivered with cesarean section, two (4.3%) perinatal deaths within seven days of delivery, one miscarriage, and 4 (9.3%) newborns were found underweight. The mean birth weight of the newborns was 3.1 kg ± 0.60. Almost half 21(48.8%) were born before 37 weeks of gestational age. Fourteen (32.6%) of newborns were born asphyxiated. Twenty-two (51.2%) of newborns developed early neonatal fever within 48 hours of delivery and treated with antibiotic. Correlation coefficient analysis revealed that weight and gestational age of newborns at birth, Apgar score at 1st and 5th minutes of birth and miscarriage were positively correlated and significantly associated with perinatal death. The occurrence of unsought pregnancy outcomes were frequent, and substantial number of pregnant women developed maternal complications. Therefore, screening pregnant women for asymptomatic bacteriuria and treating may reduce the possible maternal complications and adverse pregnancy outcomes.

Prevalence and Antimicrobial Susceptibility Profile of Staphylococcus aureus in Milk and Traditionally Processed Dairy Products in Addis Ababa, Ethiopia.

Staphylococcus aureus is a contagious pathogen that can cause various diseases in both humans and animals. Antimicrobial-resistant S. aureus is becoming an extremely important global health problem. A cross-sectional study was conducted from December 2019 to May 2020 to assess the occurrence of S. aureus and its antimicrobial susceptibility profiles in milk and traditionally processed dairy products in selected subcities of Addis Ababa. A total of 255 dairy product samples (175 raw milk and 80 traditionally processed dairy products) were collected from farms and retail markets. Samples were cultured for S. aureus according to standard microbiology techniques, and the Kirby-Bauer disk diffusion method was used to assess antimicrobial susceptibility of isolates to a panel of 12 antimicrobials. Susceptibility to methicillin was determined based on the sensitivity of isolates to cefoxitin, and resistant isolates were investigated for the presence of mecA and mecC genes using PCR. Staphylococcus aureus was isolated from 43 (24.6%) of milk, 7 (17.5%) of yogurt, and 2 (5%) of cottage cheese. A significantly higher rate of contamination with S. aureus was recorded among milk samples compared to yogurt and cottage cheese (p = 0.019). Out of 52 S. aureus isolates investigated for susceptibility to 12 antimicrobials, 49 (94.2%) of the isolates were resistant to ampicillin and 42 (80.8%) to amoxicillin+clavulanic acid. Twenty (38.5%) of the isolates were methicillin-resistant S. aureus (MRSA) based on susceptibility to cefoxitin. However, only one of these isolates (5%) was positive for mecA gene, and none of them were positive for the mecC gene. There was no significant difference (p > 0.05) in the rate of occurrence of MRSA among isolates from different sources. In conclusion, this study demonstrated a significant level of contamination of milk and dairy products with S. aureus and most isolates were multidrug resistant. The occurrence of MRSA in raw milk and dairy products signifies a serious public health threat as the practice of consuming raw dairy products in the study area is widespread. The lack of agreement between phenotypic and genotypic detection of MRSA suggests the need for further study to identify the genetic basis for the observed resistance phenotype.

Prevalence and antimicrobial susceptibility of Salmonella in poultry farms and in-contact humans in Adama and Modjo towns, Ethiopia.

Consumption of contaminated poultry and poultry products represents a common source of nontyphoidal Salmonella infection. Little is known on the status of Salmonella and their antimicrobial susceptibility in poultry farms in Ethiopia. This study investigated the prevalence, serotype distribution, and antimicrobial susceptibility of nontyphoidal Salmonella among poultry farms in Adama and Modjo towns. Three hundred thirty-four cloacal swabs, 384 fecal droppings of birds, 59 feed, 59 floor swabs, and 36 stools from in-contact humans were collected and processed for Salmonella isolation. Isolates were tested for their susceptibility to 15 antimicrobials using Kirby-Bauer disk diffusion assay. Seventeen (28.8%) of the farms and 24 (2.9%) of the samples from poultry farms and 2.8% (1/36) of stool samples of humans in-contact with poultry were positive for Salmonella. Most of the isolates (n = 21) were recovered from fecal droppings of birds while the remaining isolates were recovered from floor swab samples (n = 2) and cloacal swab sample (n = 1). Only three Salmonella serovars: S. Haifa (n = 14, 56%), S. Anatum (n = 7; 28%), and S. Give (n = 4; 16%) were detected. Poultry farms in Adama town, large flock sized farms, and farms that used antimicrobials were significantly associated with the occurrence of Salmonella (p < .05). Twenty (80%) and 19 (76%) of Salmonella isolates were resistant to streptomycin and tetracycline, respectively. Nineteen (76%) of the isolates were resistant to two or more antimicrobials. Detection of multidrug-resistant strains of Salmonella in poultry farms suggests the need for detailed epidemiological and molecular studies to establish sources of acquisition of resistant Salmonella strains.

Antimicrobial susceptibility profile of selected Enterobacteriaceae in wastewater samples from health facilities, abattoir, downstream rivers and a WWTP in Addis Ababa, Ethiopia.

Background: Evaluation of antimicrobial susceptibility profile of various bacterial pathogens in the health facilities, abattoirs and related environment is important to assess potential risk of dissemination of resistant pathogens to the environment. There is limited information about antimicrobial susceptibility profile of common Enterobacteriaceae in waste water samples from hospitals, abattoirs and the downstream water bodies in Addis Ababa. The present study assessed antimicrobial susceptibility of bacteria belonging to the family Enterobacteriaceae isolated from wastewater samples (WWS) of two hospitals: Tikur Anbessa Specialized Hospital (TASH) and Minilik II hospital, a wastewater treatment plant (WWTP) and an abattoir, and downstream rivers in Addis Ababa. Results: A total of 54 bacterial isolates belonging to 6 species were identified: E.coli (32%), Salmonella 23%), Klebsiella pneumonia (15%), Enterobacter aerogenes (11%), Citrobacter (7%), Klebsiella oxytoca (6%) and Enterobacter cloacae (6%), respectively. Two strains of Citrobacter spp. isolated from TASH wastewater sample (WWS) were resistant to all 12 antimicrobials tested whereas an E. coli isolate from the same source was resistant to 11 antimicrobials. All isolates were resistant to 2 or more antimicrobials tested. Multi-drug resistance (MDR) to several antimicrobials was recorded, particularly in isolates obtained from hospital WWS and it was more common in Citrobacter and E. coli isolates. Extended spectrum betalactamase (ESBL) production was detected in 27.3% of MDR isolates, all of them obtained from hospital effluents whereas none of the isolates were carbapenemase producers. Conclusion: The present study revealed that Enterobacteriaceae in wastewater from hospitals, abattoir and downstream water bodies are resistant to commonly used antimicrobials. Hospital effluents contained more of MDR bacteria, posing significant public health threat through dissemination to the downstream water bodies.

Prevalence and Antimicrobial Susceptibility Profile of Salmonella Serovars Isolated from Slaughtered Cattle in Addis Ababa, Ethiopia.

Salmonella is one of the top causes of foodborne bacterial illnesses in humans. The primary sources of human Salmonella infection are food producing animals such as cattle, poultry, and swine. A cross-sectional study was undertaken to estimate the prevalence and to determine the serovar distribution and antimicrobial susceptibility profiles of Salmonella spp. isolated from fecal (n=567) and carcass swab (n=159) samples of slaughtered cattle at Addis Ababa Abattoir Enterprise and Kara'alo PLC, Abattoirs, in Addis Ababa, Ethiopia between January 2014 and April 2015. Salmonella isolation was conducted according to Global Foodborne Infections Network Laboratory Protocol and isolates were confirmed by genus specific PCR and serotyped by slide agglutination test. Susceptibility of the isolates to 17 antimicrobials was testedusing the Kirby-Bauer disk diffusion method according to the guidelines of the Clinical and Laboratory Standards Institute. Out of the total 726 samples examined, 27 (3.7%) were positive for Salmonella. Salmonella was detected in 4.1% (23/567) fecal and 2.5% (4/159) carcass swab samples. Twelve different serovars were identified and the most predominant serovars were S. Dublin (n=10, 35.7%) and S. Virchow (n=5, 17.9%), followed by S. Braendrerup, S. Haifa, and S. Saintpaul which were isolated from 2 samples each (7.1%). All of the Salmonella isolates investigated were resistant or intermediately resistant to four or more of the 17 drugs tested. High resistance rate was recorded to streptomycin 25 (89.3%), cephalothin 20 (71.4%), ampicillin 19 (67.9%), and amoxicillin+clavulanic acid 19 (67.9%). Resistance to five or more antimicrobials was detected in 20 (71.5%) of the isolates. Multidrug resistance to more than 7 antimicrobials was detected in 5 (17.9%) of the isolates. Isolation of such multidrug resistant strains of Salmonella from slaughtered cattle poses a major public health concern. These findings imply the need for a strict biosecurity and regulation of antimicrobial use across the country.

Phenotypic and genotypic characterization of temporally related nontyphoidal Salmonella strains isolated from humans and food animals in central Ethiopia.

Salmonella is one of the common causes of food-borne bacterial illnesses. The primary sources of human nontyphoidal Salmonella (NTS) infection are food animals. This study characterized temporally and spatially related Salmonella isolated during April 2013 to March 2014 from faeces of diarrhoeic human patients in Addis Ababa (n = 68) and food animals (n = 84) in Addis Ababa and surrounding districts (dairy cattle, n = 30; slaughtered cattle, n = 20; poultry, n = 26; swine n = 8). Isolates were serotyped, page typed and tested for antimicrobial susceptibility using Kirby-Bauer disc diffusion method, and genotyped by pulsed-field gel electrophoresis (PFGE). The dominant Salmonella serovars isolated from food animals were S. Saintpaul (38.1%), S. Typhimurium (17.9%) and S. Kentucky (9.5%), whereas in humans, S. Typhimurium (39.7%), S. Virchow (30.9%) and S. Kottbus (10.3%) were frequently isolated. Resistance to streptomycin, sulfisoxazole, tetracycline, ampicillin and cephalothin was higher in animal isolates than human isolates, and mean number of antimicrobials to which isolates were resistant was significantly higher in isolates from cattle and poultry compared to those from humans (p < 0.05). All S. Kentucky isolated from animals and humans were multidrug resistant (MDR) with shared resistance phenotype (AmpCfCipTeSuSNa). Although this study involved small sample size and was not able to show clear epidemiological linkage among isolates from various sources, genotyping by PFGE analysis demonstrated circulation of closely related genotypes of S. Virchow, S. Typhimurium and S. Kentucky among humans and food animals. Detection of related Salmonella isolates from humans and animals, the high MDR status of isolates from animals and close proximity of farms and human residential areas in the absence of appropriate biosecurity present major public health problem. Integrated surveillance of Salmonella serovars in humans and animals and implementation of appropriate hazard analysis and pathogen control strategies along critical points of the food chain from farm to table is recommended.

Antimicrobial resistance profile of Staphylococcus aureus isolated from patients with infection at Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia.

BACKGROUND: Staphylococcus aureus is one of the major pathogens of public health importance responsible for various forms of infection. Development of resistance to commonly used antimicrobials limited treatment options against infections due to this pathogen. Antimicrobial resistance profile of Staphylococcus aureus isolated from patients with surgical site infection and ear infection and corresponding nasal swab was investigated in Tikur Anbessa Specialized Hospital (TASH), Addis Ababa, Ethiopia. METHODS: Wound and corresponding nasal swabs from patients with surgical site infection from general surgery ward (n = 14), orthopedic ward (n = 21) and those with otitis media (n = 59) from Ear Nose and Throat (ENT) ward were cultured for S. aureus isolation according to standard procedures from December 2013 to June 2014. Isolates were investigated for susceptibility to panel of 17 antimicrobials using Kirby Bauer disc diffusion assay. Susceptibility to methicillin was phenotypically determined based on sensitivity of isolates to cefoxitin and oxacillin. RESULTS: A total of 79 S. aureus isolates were recovered from 54(57.4%) of patients. The isolates were resistant to ampicillin (100%), oxacillin and cefoxitin (68.4%, each), clindamycin (63.3%), cephalothin (59.5%), tetracycline (57%), sulfamethoxazole + trimethoprim and bacitracin (53.2%, each), and erythromycin (51.9%). Resistance to two or more antimicrobials was recorded in 74 (95%) of the isolates, while resistance to 3 or more antimicrobials was detected in 65(82.3%) of the isolates. Fifty-four (68.4%) of the isolates were methicillin resistant S. aureus (MRSA). Rate of occurrence of MRSA was more common among isolates from surgical wards (p < 0.001) compared to those from ENT ward. High level of multi-drug resistance (MDR) was detected more commonly among isolates from orthopedic ward than those from general surgical ward and patients with ear infection (p < 0.001). One of the isolate cultured from wound swab of a patient with surgical site infection from orthopedic ward was resistant to all of the 17 antimicrobials tested. CONCLUSION: S. aureus isolates from patients in TASH exhibited resistance to majority of antimicrobials commonly employed for the treatment of staphylococcal infections which calls for urgent need of prudent use of antimicrobials and the need for implementation of effective infection control practices to hamper spread of MDR S. aureus.

Salmonella serotypes and their antimicrobial susceptibility in apparently healthy dogs in Addis Ababa, Ethiopia.

BACKGROUND: The close bond between pet animals and family members poses risk of infection with zoonotic bacterial pathogens such as Salmonella. No data is available on occurrence of Salmonella in dogs in Ethiopia. The aim of this study was therefore to determine the prevalence, serotype distribution and antimicrobial resistance of Salmonella from feces of apparently healthy dogs in Addis Ababa, Ethiopia. RESULTS: Of the total 360 dogs examined, 42 (11.7%; 95% Confidence limit of 8.5%-15.4%) were positive for Salmonella. Fourteen serotypes were detected and the predominant ones were S. Bronx (n = 7; 16.7%), S. Newport (n = 6; 14.3%), followed by S. Typhimurium, S. Indiana, S. Kentucky, S. Saintpaul and S. Virchow (n = 4; 9.5%) each. Salmonella infection status was significantly associated with history of symptom of diarrhea during the past 60 days (OR = 3.78; CI = 1.76-8.13; p = 0). Highest resistance rates were found for oxytetracycline (59.5%), neomycin (50%), streptomycin (38.1%), cephalothin (33.3%), doxycycline (30.9%), ampicillin (30.9%) and amoxicillin + clavulanic acid (26.2%). Thirty eight (90.5%) of the isolates were resistant or intermediately resistant to at least one of the 16 antimicrobials tested. Resistance to two or more antimicrobials was detected in 30 (71.4%) of the isolates. Resistance to three or more antimicrobials was detected in 19 (45.2%) of the isolates. CONCLUSION: This study demonstrated high carriage rate of Salmonella serotypes known for causing human salmonellosis and large proportion of them were resistant to antimicrobials used in public and veterinary medicine for management of various bacterial infections, suggesting the possible risk of infection of human population in close contact with these dogs by drug resistant pathogens. Therefore, it is vital to work on raising public awareness on zoonotic canine diseases prevention measures and good hygienic practices.

Isolation, Identification, and Antibiotic Susceptibility Testing of Salmonella from Slaughtered Bovines and Ovines in Addis Ababa Abattoir Enterprise, Ethiopia: A Cross-Sectional Study.

Salmonellae are ubiquitous, found in animals, humans, and the environment, a condition which facilitates transmission and cross contamination. Salmonella enterica serotypes exert huge health and economic impacts due to their virulence or carriage of antibiotic resistance traits. To address this significant issues with regard to public health, availability of adequate information on the prevalence and antibiotic resistance patterns of Salmonella, and establishment of adequate measures to control contamination and infection are needed. A cross-sectional study was conducted to assess the level of Salmonella infection in slaughtered bovines and ovines at Addis Ababa abattoir. Samples were collected randomly and processed for identification and antimicrobial susceptibility testing of Salmonella spp. From 280 animals examined, 13 (4.64%) (8 bovines and 5 ovines) were positive, with most samples (12/13, 92%) comprising Salmonella Dublin. Very high level of resistance to some antibiotics used in human medicine was detected. Most isolates were susceptible to gentamycin and amikacin. Nine (69%) of all isolates were resistant to multiple antibiotics. Serotyping revealed 12 of 13 isolates to be of the Dublin serotype with 9,12:g,p:- antigenic formula. This study emphasizes the importance of improving the evisceration practice during slaughtering and restricting the use of antibiotics in farm animals.

Evaluation of the in vitro antibacterial activity of the solvent fractions of the leaves of Rhamnus prinoides L'Herit (Rhamnaceae) against pathogenic bacteria.

BACKGROUND: Medicinal plants play great roles in the treatment of various infectious diseases. Rhamnus prinoides is one of the medicinal plants used traditionally for treatment of bacterial diseases. The antibacterial activity of the crude extract of the plant had been shown by a previous study, but this study was undertaken to further the claimed medicinal use of the plant by screening its solvent fractions for the said activity so that it could serve as a basis for subsequent studies. METHODS: The solvent fractions of the plant were obtained by successive soxhlet extraction with solvents of increasing polarity, with chloroform and methanol, followed by maceration of the marc of methanol fraction with water. The antibacterial activity of the solvent fractions was evaluated on seven bacterial species using agar well diffusion method at different concentrations (78 mg/well, 39 mg/well and 19.5 mg/well) in the presence of positive and negative controls. The minimum inhibitory concentration of the solvent fractions was determined by micro-broth dilution method using resazurin as indicator. RESULT: Methanol and chloroform fractions revealed antibacterial activities against the growth of test bacterial strains with varying antibacterial spectrum and the susceptible bacterial species were Staphylococcus aureus, Streptococcus pyogen, Streptococcus pneumoniae and Salmonella typhi. The average minimum inhibitory concentration value of the methanol and chloroform fractions ranged from 8.13 mg/ml to 32.5 mg/ml and from 8.13 mg/ml to 16.25 mg/ml, respectively. CONCLUSION: The methanol and chloroform fractions demonstrated significant antibacterial activities against the growth of pathogenic bacteria but the aqueous fraction did not reveal antibacterial activity against any of the test bacteria.