The emergence and spread of mobile colistin (COL) resistance (mcr) genes jeopardize the efficacy of COL, a last resort antibiotic for treating deadly infections. COL has been used in livestock for decades globally. Bacteria have mobilized mcr genes (mcr-1 to mcr-9). Mcr-gene-containing bacteria (MGCB) have disseminated by horizontal/lateral transfer into diverse ecosystems, including aquatic, soil, botanical, wildlife, animal environment, and public places. The mcr-1, mcr-2, mcr-3, mcr-5, mcr-7, and mcr-8 have been detected in isolates from and/or directly in environmental samples. These genes are harboured by Escherichia coli, Enterobacter, Klebsiella, Proteus, Salmonella, Citrobacter, Pseudomonas, Acinetobacter, Kluyvera, Aeromonas, Providencia, and Raulotella isolates. Different conjugative and non-conjugative plasmids form the backbones for mcr in these isolates, but mcr have also been integrated into the chromosome of some strains. Insertion sequences (IS) (especially ISApl1) located upstream or downstream of mcr, class 1–3 integrons, and transposons are other drivers of mcr in the environment. Genes encoding multi-/extensive-drug resistance and virulence are often co-located with mcr on plasmids in environmental isolates. Transmission of mcr to/among environmental strains is clonally unrestricted. Contact with the mcr-containing reservoirs, consumption of contaminated animal-/plant-based foods or water, international animal-/plant-based food trades and travel, are routes for transmission of MGCB.

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Antimicrobial resistance (AMR) is currently one of the major threats facing mankind. The emergence and rapid spread of multi- and pan-drug-resistant organisms (such as vancomycin-, methicillin-, extended-spectrum β-lactam-, carbapenem- and colistin-resistant organisms) has put the world in a dilemma. The health and economic burden associated with AMR on a global scale are dreadful. Available antimicrobials have been misused and are almost ineffective with some of these drugs associated with dangerous side effects in some individuals. Development of new, effective, and safe antimicrobials is one of the ways by which AMR burden can be reduced. The rate at which microorganisms develop AMR mechanisms outpaces the rate at which new antimicrobials are being developed. Medicinal plants are potential sources of new antimicrobial molecules. There is renewed interest in antimicrobial activities of phytochemicals. Nigeria boasts of a huge heritage of medicinal plants and there is avalanche of researches that have been undertaken to screen antimicrobial activities of these plants. Scientific compilation of these studies could provide useful information on the antimicrobial properties of the plants. This information can be useful in the development of new antimicrobial drugs. This paper reviews antimicrobial researches that have been undertaken on Nigerian medicinal plants.

The epidemiology of Staphylococcus aureus in food animals, associated products, and their zoonotic potential in Nigeria are poorly understood. This study aimed to provide data on the prevalence, genetic characteristics and antimicrobial resistance of S. aureus isolated from chicken and pig carcasses, and persons in contact with the carcasses at slaughterhouses in Nigeria. Surface swabs were collected randomly from 600 chicken and 600 pig carcasses. Nasal swabs were collected from 45 workers in chicken slaughterhouses and 45 pig slaughterhouse workers. S. aureus isolates were analyzed by spa typing. They were also examined for presence of the Panton-Valentine Leucocidin (PVL) and mecA genes, as well as for antimicrobial resistance phenotype. Overall, 53 S. aureus isolates were recovered (28 from chicken carcasses, 17 from pig carcasses, 5 from chicken carcass handlers and 3 from pig carcass handlers). Among the isolates, 19 (35.8%) were PVL-positive and 12 (22.6%) carried the mecA gene. The 53 isolates belonged to 19 spa types. The Based Upon Repeat Pattern (BURP) algorithm separated the isolates into 2 spa-clonal complexes (spa-CC) and 9 singletons including 2 novel spa types (t18345 and t18346). The clonal complexes (CC) detected were CC1, CC5, CC8, CC15, CC88 and CC152. CC15-related isolates represented by spa type t084 (32.1%) and CC5 represented by spa type t311 (35.3%) predominated among isolates from chicken carcasses/ handlers, and pig carcasses/ handlers, respectively. Multidrug resistance exhibited by all the CC except CC8, was observed among isolates from chicken carcasses (64.3%), pig carcasses (41.2%), handlers of chicken meat (40.0%) and handlers of pork (33.3%). All the CC showed varying degrees of resistance to tetracycline while CC15 and CC5 exhibited the highest resistance to sulphamethoxazole/trimethoprim and erythromycin, respectively. The predominant antimicrobial resistance

The mobile colistin resistance (mcr) gene threatens the efficacy of colistin (COL), a last-line antibiotic used in treating deadly infections. For more than six decades, COL is used in livestock around the globe, including Africa. The use of critically important antimicrobial agents, like COL, is largely unregulated in Africa, and many other factors militate against effective antimicrobial stewardship in the continent. Currently, ten mcr genes (mcr-1 to mcr-10) have been described. In Africa, mcr-1, mcr-2, mcr-3, mcr-5, mcr-8, and mcr-9 have been detected in isolates from humans, animals, foods of animal origin, and the environment. These genes are harboured by Escherichia coli, Klebsiella, Salmonella, Citrobacter, Enterobacter, Pseudomonas, Aeromonas, Alcaligenes, and Acinetobacter baumannii isolates. Different conjugative and nonconjugative plasmids form the backbone for mcr in these isolates; however, mcr-1 and mcr-3 have also been integrated into the chromosome of some African strains. Insertion sequences (ISs) (especially ISApl1), either located upstream or downstream of mcr, class 1 integrons, and transposons, are drivers of mcr in Africa. Genes coding multi/extensive drug resistance and virulence are colocated with mcr on plasmids in African strains. Transmission of mcr to/among African strains is nonclonal. Contact with mcr-habouring reservoirs, the consumption of contaminated foods of animal/plant origin or fluid, animal-/plant-based food trade and travel serve as exportation, importation, and transmission routes of mcr gene-containing bacteria in Africa. Herein, the current status of plasmid-mediated COL resistance in humans, food-producing animals, foods of animal origin, and environment in Africa is discussed.

BackgroundWound healing is a natural process that enables tissue repair after an injury. To shorten its duration and minimize associated complications, wounds are treated with medications. Currently there is a growing interest in the use of alternative wound dressing agents such as plant extracts. One plant used traditionally in wound treatment is Pupalia lappacea. In view of its use in wound care, we investigated the wound healing activities of 80% methanolic leave extract of Pupalia lappacea using excision, incision and dead space wound models. Also its effects on three common wound contaminants were investigated.MethodsExcision wounds were created, contaminated with microbes and treated with ointments (10% and 20% w/w) prepared from Pupalia lappacea. Incision and dead space wounds were also created in rats which were subsequently dosed orally with the extract. The wound healing activities of Pupalia lappacea ointment on excision wound was assessed by rates of wound contraction and epithelialization as well as its antibacterial effects. The effects of Pupalia lappacea on incision and dead-space wounds were determined by the wound breaking strengths and weights of the granuloma tissues formed, respectively.ResultsPupalia. lappacea ointments significantly (p < 0.05) accelerated wound healing with 20% ointment having the highest percentage wound contraction and rate of epithelialization. At 4, 7 and 14 days post treatment, mean total viable bacterial count of excision wounds of the extract treated groups were significantly (p < 0.05) lower compared against the control. Wound breaking strengths and weights of granuloma tissues formed in the extract treated groups were significantly (p < 0.05) higher than those of the control group. The minimum inhibitory concentration values obtained for the Pupalia lappacea extract against Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis were 9 mg/ml, 4 mg/ml and 3 mg/ml, respectively, while the corresponding minimum bactericidal concentrations were 10 mg/ml, 8 mg/ml and 7 mg/ml.ConclusionThe results obtained showed that Pupalia. lappacea has good wound healing and antibacterial activities. These findings validate the use of this plant in traditional medicine for treatment of wounds.

A cross-sectional survey utilizing structured questionnaires was used to study the veterinarians' perception, knowledge and practices of antibiotic stewardship (ABS) in Enugu State, Southeastern Nigeria. Data obtained were analyzed using chi-square on SPSS (Version 15.0) at a significance level of P < 0.05 to determine possible associations between variables and perceptions/knowledge about ABS. Out of 280 respondents, 41 (17.1%) had heard about ABS. Minority of the respondents perceived/knew that using antibiotics only when necessary (6.4%, 18), administering antibiotics at the appropriate dose (6.4%, 18) and administering antibiotics for appropriate duration in every case (4.3%, 12) were among the principles of ABS. The study also showed that age, gender, qualification, years of practice and locations did not exert any influence (P > 0.05) on the awareness of respondents about ABS. More than one-third of the respondents wrongly perceived that increasing the use of broad-spectrum antibiotics (35.4%, 99) is one of the goals of ABS, whereas the minority of the respondents rightly perceived/knew that minimizing toxicity and other adverse effects (16.8%, 47) and reducing antibiotic resistance (ABR) (43.2%, 121) are also goals of ABS. Only 21.4% (60) had overall knowledge of ABS. Prescribing antibiotics without seeing/examining the patient, prescribing antibiotics for any case suspected to be infectious, prescribing broad-spectrum antibiotics despite availability of narrow-spectrum antibiotics, prescribing different classes/types of antibiotics concurrently to ensure therapeutic efficacy, prescribing overdose of antibiotics to ensure efficacy and non-consultation of the veterinary formulary/other resources when in doubt during prescription, are some of inappropriate/untoward ABS practices/behaviors/attitudes amongst the respondents. No significant association (P > 0.05) was found between practices of ABS and age, gender, qualification, years of practice and location. In conclusion, the veterinarians' awareness/perception and practices of ABS is abysmally poor in the study area, thus education of Nigerian veterinarians about ABS and the teaching of the principles and practices of ABS during veterinary schools are recommended.

A cross sectional, multicentre survey utilizing a questionnaire was used to assess 6 th -(final-) year veterinary medical students' perceptions, attitude and knowledge about antibiotic resistance (ABR) and stewardship (ABS) in 5 convenientlyselected veterinary schools in Nigeria. Data obtained were analyzed by Fischer's exact and χ 2 tests at a significance level of P < 0.05. Out of 175 final-year veterinary students, 95 (54.3% i.e., response rate) completed the survey. Of the 95, 17% have heard about ABS and 7% knew the meaning of ABS. Less than 10% knew the core principles and goals of ABS and less than 20% of the respondents knew the ideal members of an ABS team. All the respondents rightly knew that no antibiotic stewardship programme (ASP) exist in veterinary hospitals in Nigeria, nearly all of them (97%) reported that antibiograms are rarely used during antibiotic (AB) prescription in their institutional veterinary teaching hospital (VTH) and about two-third (65%) believed that ABs are overused in most veterinary hospitals in Nigeria. Most of the respondents believed that ABR is of greater concern at national level than in their institutional VTHs and majority of them (92%) believed that ABR is a global problem (P = 0.009). Minority of the respondents knew that inadequate personal hygiene, use of substandard ABs, prescription of ABs by non-veterinarians/professionals, poor infection control practices, treating self-limiting infections with ABs, suboptimal and incomplete AB doses (P = 0.017), are factors that promote ABR. Minority of the respondents knew that education on AB therapy (44%), development of antibiotic usage policies (35%), reduction of AB use (14%), establishment of national AB resistance surveillance (28%) and development of institutional guidelines for AB use (29%), are critical interventions to curb ABR. Only 17% of the respondents felt that their education on ABR is adequate for their veterinary career. Most of the respondents believed that strong knowledge of ABs is important for their future veterinary career and would like more education about ABR and ABS. Overall mean correct score of 29% on clinical knowledge vignettes with similar scores across the schools in all the areas, was recorded. This survey has shown that Nigerian veterinary students' perception and knowledge about ABR and ABS are poor and therefore creates doubt about their preparedness to practice ABS. There is urgent need for improved ABS education in Nigerian veterinary schools.