Isoken H. Igbinosa

Emerging Aeromonas Species Infections and Their Significance in Public Health

Aeromonas species are ubiquitous bacteria in terrestrial and aquatic milieus. They are becoming renowned as enteric pathogens of serious public health concern as they acquire a number of virulence determinants that are linked with human diseases, such as gastroenteritis, soft-tissue, muscle infections, septicemia, and skin diseases. Proper sanitary procedures are essential in the prevention of the spread of Aeromonas infections. Oral fluid electrolyte substitution is employed in the prevention of dehydration, and broad-spectrum antibiotics are used in severe Aeromonas outbreaks. This review presents an overview of emerging Aeromonas infections and proposes the need for actions necessary for establishing adequate prevention measures against the infections.

Toxicological Profile of Chlorophenols and Their Derivatives in the Environment: The Public Health Perspective

Chlorophenol compounds and their derivatives are ubiquitous contaminants in the environment. These compounds are used as intermediates in manufacturing agricultural chemicals, pharmaceuticals, biocides, and dyes. Chlorophenols gets into the environment from a variety of sources such as industrial waste, pesticides, and insecticides, or by degradation of complex chlorinated hydrocarbons. Thermal and chemical degradation of chlorophenols leads to the formation of harmful substances which constitute public health problems. These compounds may cause histopathological alterations, genotoxicity, mutagenicity, and carcinogenicity amongst other abnormalities in humans and animals. Furthermore, the recalcitrant nature of chlorophenolic compounds to degradation constitutes an environmental nuisance, and a good understanding of the fate and transport of these compounds and their derivatives is needed for a clearer view of the associated risks and mechanisms of pathogenicity to humans and animals. This review looks at chlorophenols and their derivatives, explores current research on their effects on public health, and proffers measures for mitigation.

Polyphenolic contents and antioxidant potential of stem bark extracts from Jatropha curcas (Linn).

We assessed the polyphenolic contents and antioxidant potential of the aqueous, ethanol and methanol stem bark extracts of Jatropha curcas. The total phenol, flavonoids, flavonols and proanthocyanidin contents of the extracts were evaluated to determine their effect on the antioxidant property of this plant, using standard phytochemical methods. The antioxidant and free radical scavenging activity of ethanol, methanol and aqueous extracts of the plant were also assessed against 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), ferric reducing, nitric oxide (NO), superoxide anion, (O2−) and hydrogen peroxide (H2O2) using spectroscopic methods and results were compared with that of butylated hydroxyl toluene (BHT) and ascorbic acid as standards. The concentrations of different classes of phenolic compounds were higher in methanol and ethanol extracts compared to aqueous extracts. There was correlation between total phenol, total flavonoids, total flavonol and total proanthocyanidins (r = 0.996, 0.978, 0.908, and 0.985) respectively. There was correlations between the amount of phenolic compounds and percentage inhibition of DPPH radicals scavenging activity of the extract (r = 0.98). Findings from the present study indicated that J. curcas is a potential source of natural antioxidants and may be a good candidate for pharmaceutical plant based products.

Antibiotic Susceptibility Profile of Aeromonas Species Isolated from Wastewater Treatment Plant

This study assessed the prevalence of antibiotic-resistant Aeromonas species isolated from Alice and Fort Beaufort wastewater treatment plant in the Eastern Cape Province of South Africa. Antibiotic susceptibility was determined using the disc diffusion method, and polymerase chain reaction (PCR) assay was employed for the detection of antibiotics resistance genes. Variable susceptibilities were observed against ciprofloxacin, chloramphenicol, nalidixic acid, gentamicin, minocycline, among others. Aeromonas isolates from both locations were 100% resistant to penicillin, oxacillin, ampicillin, and vancomycin. Higher phenotypic resistance was observed in isolates from Fort Beaufort compared to isolates from Alice. Class A pse1 β-lactamase was detected in 20.8% of the isolates with a lower detection rate of 8.3% for blaTEM gene. Class 1 integron was present in 20.8% of Aeromonas isolates while class 2 integron and TetC gene were not detected in any isolate. The antibiotic resistance phenotypes observed in the isolates and the presence of β-lactamases genes detected in some isolates are of clinical and public health concern as this has consequences for antimicrobial chemotherapy of infections associated with Aeromonas species. This study further supports wastewater as potential reservoirs of antibiotic resistance determinants in the environment.

Antibiogram, Adhesive Characteristics, and Incidence of Class 1 Integron in Aeromonas Species Isolated from Two South African Rivers

Aeromonas species are well distributed in freshwater environments, and their natural susceptibility to antimicrobials renders them interesting candidates for the survey of antimicrobial resistance in freshwater milieu. Water samples were collected from Kat and Tyume rivers in the Eastern Cape province of South Africa, and a total of 45 isolates identified as Aeromonas species were recovered from the two rivers. All Aeromonas isolates were resistant to oxacillin, penicillin, clindamycin, cephalothin, vancomycin, and rifamycin, while appreciable susceptibilities (89.3 : 94.1%, 82.1 : 94.1%, 85.7 : 88.2%, and 92.9 : 88.2%) were observed against ciprofloxacin, chloramphenicol, nitrofurantoin, and gentamicin from Kat and Tyume rivers, respectively. Multiple antibiotic resistance (MAR) indices ranged from 0.016 to 0.044 for the two rivers. Class 1 integron was detected in about 20% of the isolates, and all the isolates except one showed ability to produce biofilm in vitro as weak producers (53.33%), moderate producers (15.56%), and strong producers (28.9%). This investigation provides a baseline data on antibiotic resistance as well as the adhesive characteristics of Aeromonas isolates from Tyume and Kat rivers in the Eastern Cape province of South Africa.

Commensal Pseudomonas Species Isolated from Wastewater and Freshwater Milieus in the Eastern Cape Province, South Africa, as Reservoir of Antibiotic Resistant Determinants

Pseudomonas species are opportunistic pathogens with implications in a wide range of diseases including cystic fibrosis and sickle cell anaemia. Because of their status as multidrug resistant (MDR) and extremely drug resistant (XDR) bacteria Pseudomonas species represent a threat to public health. Prevalence, antibiogram and associated antibiotic resistant genes of Pseudomonas species isolated from freshwater and mixed liquor environments in the Eastern Cape Province of South Africa were assessed. Polymerase chain reaction (PCR) based technique was used to identify the isolates and screen for antibiotic resistant genes. The result shows occurrence of Pseudomonas spp. in freshwater and mixed liquor as follows: 71.42% and 37.5% (P. putida), 14.28% and 31.25% (P. flourescens), 7.14% and 6.25% (P. aeruginosa) and 7.14% and 25% for other Pseudomonas species respectively. Disk diffusion antibiogram of the Pseudomonas isolates from the two locations showed 100% resistance to penicillin, oxacillin, clindamycin, rifampicin and 100% susceptibility to ciprofloxacin and gentamicin with varied percentage resistances to cephalothin, nalidixic acid, tetracycline, and ampicillin. The blaTEM antibiotic resistant gene was detected in 12.5% of P. putida, 57.14% of P. fluorescens, 100% P. aeruginosa and 40% in other Pseudomonas species. Similarly, Integrons conserved segment were detected in 12.5% of P. putida, 57.14% of P. fluorescens, 100% of P. aeruginosa and 40% of other Pseudomonas species. The presence of blaTEM gene and integrons conserved segment in some of the isolates is worrisome and suggest Pseudomonas species as important reservoirs of multidrug resistance genes in the Eastern Cape Province environment.

Detection and distribution of putative virulence associated genes in Aeromonas species from freshwater and wastewater treatment plant

The detection of genes responsible for Aeromonas virulence is a vital tool in establishing the potential pathogenicity of the bacteria, as these virulence genes may act alone or in synergy in the establishment of infections. Freshwater and wastewater mixed liquor samples were collected from Kat river and Fort Beaufort wastewater treatment plant in the Eastern Cape Province of South Africa. Polymerase chain reaction was utilized for the amplification of the different genes coding for virulence. All virulence associated genes screened (alt, lip, fla, aer, ast, hlyA) were detected in at least one Aeromonas isolates. In fresh water sample, virulence genes were distributed as follows: lip (67%), aer (43%), alt (33%), fla (62%), ast (10%), and hlyA (86%), while in wastewater samples the occurrence were as follows: lip (92%), aer (21%), alt (54%), fla (83%), ast (29%), and hlyA (88%). The presence of these virulence genes in environmental Aeromonas isolates is of concern to public health as these organisms are potential pathogens in the environment and the virulence determinants could be transferred to aquatic organisms and humans by one mechanism or the other.

Antibiotic Synergy Interaction against Multidrug-Resistant Pseudomonas aeruginosa Isolated from an Abattoir Effluent Environment

Pseudomonas aeruginosa is an opportunistic pathogen in environmental waters with a high prevalence of multidrug resistance. In this study the synergistic efficacy of synergy antibiotic combinations in multidrug-resistant P. aeruginosa strains isolated from an abattoir effluent was investigated. Water samples were processed using membrane filtration; Pseudomonas was isolated with Pseudomonas Isolation Agar and confirmed using polymerase chain reaction with specie-specific primer. Susceptibility studies and in vitro synergy interaction testing were carried out, employing agar dilution and Etest procedure, respectively. Resistance was noted for clinically relevant antipseudomonal agents tested. Finding from antibiotic synergy interaction studies revealed that cefepime, imipenem, and meropenem combined with amikacin resulted in statistically significant (P < 0.0001) in vitro antibiotics synergy interaction, indicating the possible use of this regimen in treatment of pseudomonal infections.

Effects of Biochemical Alteration in Animal Model after Short-Term Exposure of Jatropha curcas (Linn) Leaf Extract

This study aims to evaluate potential toxic effect of Jatropha curcas leaves methanol extract on laboratory rats as well as determine its LD50. A total of 80 male Wistar rats were used as the experimental animals, 40 for LD50 determination and the other 40 for toxicity study. Based on the pretest that was done in order to establish a range of toxicity, 4 dosages (86.00, 58.00, 46.00, and 34.0 kg/body weight) were chosen. The rats were randomly assigned into four groups with 10 rats in each group. Rats in groups 1, 2, 3, and 4 were given 0 mg/kg, 500 mg/kg, 1000 mg/kg, and 2000 mg/kg body weight of Jatropha curcas extract, respectively, by oral intubation for 21 days. Thereafter, clinical signs, change in body weight, toxicity symptoms, and biochemical parameters were obtained. The LD50 at 95% confidence limits for rats was 46.0 mg/kg body weight (44.95–52.69 mg/kg body mass). There was no clinical and biochemical signs of toxicity when the extract was administered at 500, 1000, and 2000 mg/kg body weight, respectively (P > 0.05). Results obtained from this study suggest that liver, kidney, and haematological system of rats tolerated methanolic leave extract of Jatropha curcas at a certain concentration.

Antibiogram profiling and pathogenic status of Aeromonas species recovered from Chicken

Poultry meat and its products are widely consumed by humans globally, however, Aeromonas infections in poultry have been reported in different parts of the world with devastating effects. This study was carried out to assess the antibiogram and biofilm forming potential of Aeromonas isolated from chicken fecal samples. Aeromonas isolates were screened for antibiotic susceptibility using antibiotics disk and biofilm producing potentials on abiotic surfaces. Nineteen isolates recovered from chicken feces were 100% sensitive to ciprofloxacin, gentamicin and the tetracyclines. About 53% of Aeromonas isolates were resistant to erythromycin and 47% resistant to streptomycin. Eight isolates (42.1%) were found to be moderate producers of biofilm, 31.6% (6/19) were weak producers of biofilm, 10.5% (2/19) were non biofilm producers while 15.8% (3/19) were strong producers. The present investigation shows a prevalence of potentially pathogenic Aeromonas strains in chicken feces, suggesting potential group at risk for Aeromonas infection which could be dissemination to other animals or humans with close contact and the wider community.