The mutual control of iron and erythropoiesis.

BACKGROUND: Iron is essential for hemoglobin synthesis during terminal erythropoiesis. To supply adequate iron the carrier transferrin is required together with transferrin receptor endosomal cycle and normal mitochondrial iron utilization. Iron and iron protein deficiencies result in different types of anemia. Iron-deficiency anemia is the commonest anemia worldwide due to increased requirements, malnutrition, chronic blood losses and malabsorption. Mutations of transferrin, transferrin receptor cycle proteins, enzymes of the first step of heme synthesis and iron sulfur cluster biogenesis lead to rare anemias, usually accompanied by iron overload. Hepcidin plays an indirect role in erythropoiesis by controlling plasma iron. Inappropriately high hepcidin levels characterize the rare genetic iron-refractory iron-deficiency anemia (IRIDA) and the common anemia of chronic disease. Iron modulates both effective and ineffective erythropoiesis: iron restriction reduces heme and alpha-globin synthesis that may be of benefit in thalassemia. MATERIAL AND METHODS: This review relies on the analysis of the most recent literature and personal data. RESULTS: Erythropoiesis controls iron homeostasis, by releasing erythroferrone that inhibits hepcidin transcription to increase iron acquisition in iron deficiency, hypoxia and EPO treatment. Erythroferrone, produced by EPO-stimulated erythropoiesis, inhibits hepcidin only when the activity of BMP/SMAD pathway is low, suggesting that EPO somehow modulates the latter signaling. Erythroblasts sense circulating iron through the second transferrin receptor (TFR2) that, in animal models, modulates the sensitivity of the erythroid cells to EPO. DISCUSSION: The advanced knowledge of the regulation of systemic iron homeostasis and erythropoiesis-mediated hepcidin regulation is leading to the development of targeted therapies for anemias and iron disorders.

One size does not fit all: the emerging frontier in large-scale marine conservation.

On the 20th anniversary of the Convention on Biological Diversity, a network of very large marine protected areas (the Big Ocean network) has emerged as a key strategy in the move to arrest marine decline and conserve some of the last remaining relatively undisturbed marine areas on the globe. Here we outline the ecological, economic and policy benefits of very large-scale MPAs and show their disproportionate value to global marine conservation targets. In particular we point out that very large-scale MPAs are a critical component of reaching the Aichi targets of protecting 10% of global marine habitats by 2020, because in addition to encompassing entire ecosystems, they will bring forward the expected date of achievement by nearly three decades (2025 as opposed to 2054). While the need for small MPAs remains critical, large MPAs will complement and enhance these conservation efforts. Big Ocean sites currently contain more than 80% of managed area in the sea, and provide our best hope for arresting the global decline in marine biodiversity.

CHARACTERISATION OF BACTERIAL ISOLATES FROM PATIENTS WOUNDS AND ENVIRONMENTAL FACTORS PREDICTIVE OF POST-SURGICAL INFECTIONS AT THE ORTHOPAEDIC WARD IN ILE-IFE, NIGERIA.

OBJECTIVE: To determine the pattern of orthopaedic wound infection and the influence of environmental factors on the distribution of the etiologic bacterial agents. DESIGN: A prospective observational study. SETTING: Department of Orthopaedic Surgery and Traumatology, Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria. SUBJECTS: Sixty patients with orthopaedic wound infections and orthopaedic ward environment. RESULTS: Thirty- nine males (mean age 33.31+2SD) and 21 females (mean age 27.47 + 2SD) with orthopaedic wounds. Three hundred and ten bacteria (190 from patients and 120 from ward environment) were isolated. The pattern of bacterial isolates from patients' wounds was different from that of the airborne bacterial isolates irrespective of the length of stay on the ward. There was a significant difference in the distribution and resistance pattern of bacterial isolates from the patient's wounds and ward environment. CONCLUSION: There is a high incidence of antibiotic resistance of bacterial isolates from samples cultured from patients compared with isolates from ward environment at this centre. The extensive use of pre-operative prophylactic and post-surgical antibiotics in various combinations at this centre needs to be re-examined to reduce the preponderance of antibiotic resistance.

Superficial swab cultures in open fracture management: insights from a resource-poor setting.

OBJECTIVE: To identify bacterial isolates from superficial swabs of open fracture wounds at presentation and after infection has been established, and to determine if there are correlations between them. METHOD: Patients who presented with open fractures at the Wesley Guild Hospital, Ilesa, Nigeria between December 2004 and May 2006 were recruited into this prospective study. Superficial wound swabs were taken at presentation and if patient showed evidence of wound infection. RESULTS: Sixty patients had open fractures. The initial bacteria culture of wound swabs taken on the day of presentation was positive in 41 (68.3%) patients. Of these, 19 (46.3%) yielded one bacteria isolate, 17 (41.5%) yielded two and 5 (12.2%) yielded three, making a total of 68 organisms. The most common organism was Staphylococcus aureus. However, as a group, more aerobic Gram-negative rods were isolated than any other bacteria groups. Eleven (18.3%) patients developed wound infections, all of which were polymicrobial. In 10 (90.9%) of these, the microbial isolate of the final wound swab included at least one organism that was present in the initial wound culture. No patient with an initial negative culture went on to develop a wound infection. The mean presentation interval of patients with wounds that became infected was 15.2 ± 7.9 hours (95% CI 9.8-20.5 hours) compared with 2.9 ± 3.1 hours (95% CI 2.0-3.8 hours) for those who did not develop a wound infection (p>0.01). CONCLUSION: In a resource-poor setting, where pre-hospital care is unavailable and patients present late, superficial wound swabs are effective in predicting subsequent organisms that may cause wound infections. CONFLICT OF INTEREST: None.

A comparison of superficial and deep bacterial presence in open fractures of the lower extremities.

This open prospective study compared the bacterial flora of superficial and deep-wound biopsies and swabs over a 2-year period in 4 different samples cultured from open fracture wounds at the Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria. Samples were taken from 47 patients with factures graded according to Gustilo and Anderson's classification as grade 1 (2.1%), grade II (29.8%), grade IIIA (36.2%), and grade IIIB (31%). A total of 248 samples were cultured using standard techniques. The incidence of open fracture wounds was 78.7% in male patients and 21.3% in female patients. Tibia fractures constituted 66.1%. A total of 203 bacterial isolates were cultured from 248 samples. Gram-negative bacteria constituted 53.2% of isolates, with Escherichia coli being predominant (12.8%). Staphylococcus aureus were the predominant Gram-positive cocci (15.3%), and Staphylococcus epidermidis (13.3%) may be considered to be the major source of open fracture wound contamination. The bacterial species cultured from superficial and deep-wound swabs and biopsies were similar. Resistance to antimicrobials was high for penicillins (amoxicillin and cloxacillin), with values of 68.6% and 58.3%, respectively, for superficial bacterial species and 58.2% and 31.9%, respectively, for deep-wound biopsies.

Microbial isolates in early swabs of open musculoskeletal injuries.

BACKGROUND: Infections of open musculoskeletal injuries, especially open fractures, continue to pose a challenge to the Orthopaedic and Trauma surgeons. There is a dearth of information on the early bacterial contaminants of these open wounds and their antibiotic sensitivity patterns in our environment. OBJECTIVE: To determine the bacteriology of open wounds of the musculoskeletal system at initial presentation in hospital and their antibiotic susceptibility profile in Ile-Ife, Nigeria. MATERIALS AND METHODS: A prospective study of 86 consecutive patients over an eight-month period (March to October 2002). Eighty-six patients with 96 open wounds of the musculoskeletal system admitted to the Accident and Emergency unit of the Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife. Bacteria were isolated from swabs taken from the depth of the wounds and their antibiotic susceptibility determined. RESULTS: A total of 126 bacterial isolates were recovered from 96 wounds in 86 patients (61 males and 25 females) with mean age of 31.4 years +/- SD. About 73.3% of the wounds were from road traffic accidents and 72.3% of the wounds were severe open fractures (Grades IIIA to C). Staphylococcus aureus constituted 22.2% while coagulase negative Staphylococci (CONS) accounted for 21.4% with Staphylococcus. epidermidis leading the group with 13.5%. Gram negative rods constituted 40.5% of the isolates with Pseudomonas aeruginosa accounting for 11.1%. Antibiotic sensitivity profile revealed that many of the isolates were multiply resistant to the antimicrobials employed but were sensitive to Ofloxacin. CONCLUSION: This study has shown that open wounds of the musculoskeletal system are usually contaminated at presentation with pathogenic organisms. The antibiotic sensitivity pattern of the isolates shows that the quinolones, represented by Ofloxacin, is the most effective antibiotic.

Bacterial isolates in the sick young infant in Ile-Ife, Nigeria.

This prospective study was carried out to determine the bacterial pathogens and their antibiotic sensitivity profile in the sick young infant. All consecutive young infants with features suggestive of infection seen over 5 months at a Comprehensive Health Centre in Ile-Ife, were screened for septicaemia and local bacterial infections. Of the 121 sick young infants screened for infection, 94 (77.7 per cent) had confirmed bacterial infection and 54 (57.4 per cent) of the 94 had confirmed septicaemia. Gram-positive organisms were the commonest bacterial isolates accounting for 204 (81.6 per cent) of the 250 isolates in this study. Staphylococcus aureus was the most frequent organism accounting for 61.2 per cent of all isolates. Gram-negative organisms accounted for 46 (18.4 per cent) of all isolates with Salmonella spp. and Proteus vulgaris predominating. All the bacterial isolates in this study were sensitive to ofloxacin and most were sensitive to the antibiotics commonly employed in the treatment of infections caused by these organisms. However, many of both Grampositive and Gram-negative isolates in this study were resistant to cotrimoxazole. The study highlights the high prevalence of bacterial infections (localized or systemic) among young infants. It also shows that Gram-positive organisms, the principal aetiologic agents, were sensitive to commonly used antibiotics. It is recommended that genticin and cloxacillin or erythromycin should be used as the first-line antibiotics in the treatment of young infants with bacterial infections in Ile-Ife, Nigeria.

The bacteriology of open fractures in Ile-Ife, Nigeria.

BACKGROUND: The objective of this study is to determine the pattern of bacterial isolates and antibiotic sensitivity profile in open fractures. Fifty-nine patients with open fractures of the lower limb long bones were studied. The majority of the cases were Gustilo and Anderson types II 21(35.6%), and IIIA 16(27.1%). METHOD: The patients were assessed by history taking, physical examination, and plain radiographs. Wound swabs were taken for bacteriological studies. Other necessary investigations were also done. During wound debridement open fractures were classified into Grades I, II and III using the Gustilo-Anderson method of classification. RESULTS: The infection rate was 45.8%. Gram-positive cocci and Gram-negative rods were isolated. On the whole Staphylococcus aureus 13(25%), and Coagulase-negative staphylococci (CONS) 14(26.9%), were the commonest organisms isolated. The commonest Gram-negative rods that were isolated from the wounds were Proteus mirabilis 9(17.3%), and Pseudomonas aeruginosa 8(15.4%). Multiple organisms were commonly isolated from the wounds. While all the organisms isolated showed very good sensitivity to gentamicin, cloxacillin and ofloxacin, most of the organisms were resistant to penicillin, ampicillin and tetracycline. The sensitivity ranged from 62.5% to 100%. Coagulase-negative Staphylococci (CONS) showed sensitivity to the widest range of antibiotics which included penicillin, ampicillin, chloramphenicol, gentamicin, cloxacillin and ofloxacin. The sensitivity ranged from 35.7% to 100%. There was statistically significant difference between the open tibial and femoral fracture cases with respect to the interval between injury and debridement time (p = 0.008); the rate of wound infection (p = 0.021); and the occurrence of osteomyelitis (p = 0.023). The commonest complications observed were wound infection 27(45.8%), and delayed fracture union 26(44.1%), which were commoner in the open tibial fractures. CONCLUSION: This study shows that Staphylococcus aureus and coagulase-negative staphylococci (CONS) were the commonest organisms associated with open fracture of the lower limbs in our centre and that delay in the initial wound debridement was a major predisposing factor to wound infection.

The characterization of bacterial isolates from acute otitis media in Ile-Ife, southwestern Nigeria.

The incidence of acute otitis media (AOM) in a comprehensive healthcare setting was investigated in Ile-Ife, Nigeria. Out of the 617 children examined, 53 (11.64 per cent) suffered from the condition based on the criteria used. Staphylococci constituted the predominant organisms associated with the condition with Staphylococcus aureus (25.0 per cent) being the most frequent single microbe recovered from the subjects. This was followed by Proteus mirabilis (16.2 per cent), Staphylococcus sp. (8.8 per cent), Streptococcus pneumoniae (8.8 per cent), Pseudomonas aeruginosa and Haemophilus influenzae (7.4 per cent each). Most isolates tested were multiply resistant to the antibiotics commonly employed in treating infections caused by these organisms. The study highlights the prevalence of multi-resistant organisms amongst the subjects and recommends prompt therapeutic intervention to avert ineffectiveness of antibiotics when used in treating infections caused by these organisms in the community.

Sero-prevalence of HIV antibodies in tuberculosis patients in Ile-Ife, Nigeria.

BACKGROUND: The acquired immunodeficiency syndrome (AIDS) is of major public health concern worldwide more so in sub-Saharan Africa where there is an upsurge in the incidence of the disease. Reports from developed countries have shown that a close link exists between the human immunodeficiency virus (HIV) and pulmonary tuberculosis. No such study has ever been carried out in Ile-Ife, Nigeria. OBJECTIVE: The study was designed to determine the prevalence of HIV infection among randomly selected tuberculosis patients seen in a Nigerian chest clinic using third generation ELISA kits that detect HIV-1 and HIV-2 strains. RESULTS: Of the 79 subjects with confirmed active tuberculosis, 12.7% tested positive for HIV antibodies compared with 2.0% of subjects without tuberculosis designated as the control group--a value that is statistically significant (p < 0.05). Farmers, artisans and students contributed a large proportion of the seropositive sera. Although the seroprevalence rate of 12.7% is low compared with the rates from eastern and southern African countries, this value was threefold higher than 5.2% value reported in metropolitan Lagos--suggesting concern about the spread of HIV in a semi-urban centre such as Ile-Ife. CONCLUSION: This study suggests that a close link exists between active tuberculosis and HIV infection in Ile-Ife, Nigeria which underscores the urgent need to monitor tuberculosis patients as the increase in the rate of new cases may indicate the spread of HIV infection. The study also recommends that an aggressive public awareness programme be undertaken to enlighten communities about the risk of TB/HIV infection.

The bacteriology of neonatal septicaemia in Ile-Ife, Nigeria.

The incidence of septicaemia among neonates categorized as being at high risk was 55 per cent in Ile-Ife, Nigeria. Gram-positive organisms, specifically Staphylococcus aureus, were predominant (33.8 per cent) among bacteria cultured from proven cases of septicaemia. Other coagulase-negative staphylococci also contributed 21 per cent, with Staphylococcus epidermidis occurring in 5 per cent of the isolates. Listeria monocytogenes was cultured from 8.4 per cent of septic neonates. Pseudomonas aeruginosa was cultured from 3 per cent, Klebsiella pneumoniae from 14 per cent, and Escherichia coli from 7 per cent. Other Gram-negative bacilli cultured were Enterobacter aerogenes (5 per cent), Citrobacter freundii, Salmonella sp., and Proteus sp. (2 per cent each). The bacterial isolates were relatively resistant to antibiotics traditionally employed to treat cases of septicaemia. The study shows a high prevalence of neonatal bacterial sepsis at the centre and the emerging role of Listeria monocytogenes in the aetiology of neonatal sepsis. It highlights the preponderance of multiple antibiotic resistant organisms among these neonates early in life which is of epidemiological importance in the control of the infectious agents.

Transferable antibiotic resistance in Escherichia coli isolated from healthy Nigerian school children.

Three hundred and ninety-six E. coli isolates obtained from apparently healthy school children in Ile-Ife, Nigeria, were tested for their susceptibility to 11 different antibiotics. Of these, only gentamicin, cefotaxime and nalidixic acid were found to have significant in vitro activity against most of the isolates. The incidence of antibiotic resistances encountered varied between 24% for trimethoprim and 55.5% for the sulphonamide. It was further observed that 47.5% of the isolates were identified as being multiply resistant, since they were simultaneously resistant to at least three different antibiotics. The 86 trimethoprim-resistant isolates tested were found to be able to transfer this resistance trait together with resistance genes of to other antibiotics, into a plamidless strain of E. coli by conjugation. Seventy-seven of the trimethoprim-resistant isolates were also found to be classifiable into the types of dihydrofolate reductases responsible for the observed resistance on the basis of hybridization experiments. The results of this study indicate that there is a large reservoir of antibiotic resistances within the community, and that the resistance genes were easily transferable to other strains even without direct exposure to antibiotics.

Incidence of pathogenic microorganisms in clinical specimens from hospitals in south-western Nigeria.

The pattern and frequency of bacterial isolates cultured from 687 clinical specimens from four University teaching hospitals in South Western Nigeria were determined. A total of 707 bacterial isolates were cultured from 18 different clinical sources giving an average of 1.03 bacteria per sample identified in this collection. Of these, gram negative rods constituted 78.1% and the rest were staphylococci. The most common organism isolated in urine samples was E. coli (32.1%) whilst S. aureus (28.9%) was the most frequently isolated organism from wounds. An interesting observation was the significant occurrence of Aeromonas hydrophilia and Klebsiella pneumoniae in urine samples.

A study of urinary tract infections at Ile-Ife, Nigeria.

Clinical laboratory records and case files of 1,038 cases of urinary tract infections (UTI) were examined for the spectrum of bacterial and candida isolates for age and sex distribution of the UTI cases and antibiotic susceptibility pattern of isolates. The results show that 867 (83.5%) of the cases were aged 21 years and above, of which 81.3% in that age group were females. While only 20.7% of the cases were males, 74.0% of those in that category were also 21 years and older. Eleven organisms were isolated, with E. coli, Klebsiella spp and Staphylococcus aureus respectively representing 36.1%, 22.8% and 15.4% of the total bacterial isolates. The prevalence of S. aureus isolates in cases of UTI in this centre suggests the increasing role of these microorganisms in the aetiology of urinary tract infections in Nigeria.

Sources of intra-operative bacterial colonization of clean surgical wounds and subsequent post-operative wound infection in a Nigerian hospital.

The incidence of postsurgical clean wound infection in 101 consecutive operations was 1.98%. Staphylococci were the predominant bacteria cultured from the anterior nares of the patients and attending surgical personnel--and were found to colonize the wounds. The nasal carriage rates of Staphylococcus aureus amongst the patients and surgical staff were 12.1% and 17.% respectively. Group III and non-typeable (NT) S. aureus strains accounted for about 65% of S. aureus isolates cultured from the anterior nares. A low incidence of nasal carriage of S. aureus isolates correlated with low incidence of wound sepsis. The operating room air seemed considerably contaminated but this did not reflect in high incidence of postsurgical wound sepsis. Our results suggest patients microflora and operating room air were the major sources of intra-operative bacterial colonization of wound at this centre.

The characterisation of clinical isolates of Staphylococcus aureus in Ile-Ife, Nigeria.

Of 166 strains of Staphylococcus aureus isolated from hospital patients and staff in Ile-Ife, Nigeria, 32% were non-typable (NT). The strains were isolated from skin lesions, eye infections, wounds and nasal flora. Isolates from skin lesions or eye and wound infections were more likely to produce protease (95% and 78% respectively) than nasal isolates (11%). Nearly all (99%) of the strains isolated were resistant to penicillin and 78% were resistant to tetracycline. Streptomycin resistance occurred in 25% of isolates; 19% were resistant to chloramphenicol and 9% to methicillin.

A survey of nasal carriage of Staphylococcus aureus in a neonatal ward in Ile-Ife, Nigeria.

The nasal carriage rate of Staphylococcus aureus among maternal-infant pairs was 18% compared with 39% among hospital staff in Ile-Ife, Nigeria during a 12-week survey. Of the newborns, 46% tested positive compared with 26% of their mothers. The S. aureus phage types recovered were predominantly of the group III type (38%); however, 28% of the strains isolated were non-typable. All the S. aureus strains were resistant to penicillin, 84% to tetracycline, and 35 and 24% were resistant to streptomycin and chloramphenicol, respectively. Altogether 19% of the strains tested were resistant to methicillin.

The bacteriology of intra-abdominal abscesses in Nigerian children.

The bacteriology of intra-abdominal abscess in 30 Nigerian children showed anaerobic bacteria constituted 52 per cent of total microflora with Bacteroides fragilis and anaerobic streptococci (19 per cent each) being predominant. E. coli and S. aureus were the predominant facultative bacteria isolated occurring in 24 and 11 per cent, respectively. The incidence of abscess was higher in males than in females and these predominant bacteria were relatively resistant to penicillins, suggesting caution in the use of penicillins in the treatment of intra-abdominal infections.

Transmissible trimethoprim resistance in strains of Escherichia coli isolated from cases of infantile diarrhoea.

Of 190 isolates of Escherichia coli from children aged up to 5 years with diarrhoea, 72 (37.9%) were resistant to trimethoprim and of the 70 isolates tested, 38 transferred high level trimethoprim resistance (MIC greater than 1000 mg/L) into E. coli EC 1005. Of the enterotoxigenic isolates from which trimethoprim resistance was transferred, 41.2% also contained transmissible toxigenic characteristics. All the trimethoprim-resistant isolates were resistant to other antibiotics.