Communicable Disease Epidemiology following Migration: Studies from the African Famine

Few epidemiological studies have been undertaken of morbidity and mortality due to communicable disease in mass migration. This article reviews data from refugee displacement areas in north-east Africa. Risk factors to increase morbidity and mortality include breakdown of health services, movement to new ecological zones, malnutrition, and crowding and poor sanitation in relief camps. Highest mortalities are recorded in chidren below five years, the principal causes being measles, gastro-enteritis, chest infections and malaria. The greatest morbidity and mortality occurs after arrival in relief camps, and could be reduced by epidemiologically based, selective health programs. This article stresses the importance of regional level coordination between relief agencies and the need for an effective disease surveillance system.

Ebola virus disease in Africa: epidemiology and nosocomial transmission

The 2014 Ebola outbreak in West Africa, primarily affecting Guinea, Sierra Leone, and Liberia, has exceeded all previous Ebola outbreaks in the number of cases and in international response. There have been 20 significant outbreaks of Ebola virus disease in Sub-Saharan Africa prior to the 2014 outbreak, the largest being that in Uganda in 2000, with 425 cases and a mortality of 53%. Since the first outbreaks in Sudan and Zaire in 1976, transmission within health facilities has been of major concern, affecting healthcare workers and acting as amplifiers of spread into the community. The lack of resources for infection control and personal protective equipment are the main reasons for nosocomial transmission. Local strategies to improve infection control, and a greater understanding of local community views on the disease, have helped to bring outbreaks under control. Recommendations from previous outbreaks include improved disease surveillance to enable more rapid health responses, the wider availability of personal protective equipment, and greater international preparedness.

Poverty and infection in the developing world: healthcare-related infections and infection control in the tropics

In many hospitals serving the poorest communities of Africa and other parts of the developing world, infection control activities are limited by poor infrastructure, overcrowding, inadequate hygiene and water supply, poorly functioning laboratory services and a shortage of trained staff. Hospital transmission of communicable diseases, a high prevalence of human immunodeficiency virus and multidrug-resistant tuberculosis, lack of resources for isolation and disinfection, and widespread antimicrobial resistance create major risks for healthcare-related infections. Few data exist on the prevalence or impact of these infections in such environments. There is a need for interventions to reduce the burden of healthcare-related infections in the tropics and to set up effective surveillance programmes to determine their impact. Both the Global (G8) International Development Summit of 2005 and the United Nations Millennium Development Goals (MDGs) have committed major resources to alleviating poverty and poor health in the developing world over the next decade. Targeting resources specifically to infection control in low-resource settings must be a part of this effort, if the wider aims of the MDGs to improve healthcare are to be achieved.

A survey of antimicrobial prescribing and dispensing practices in rural Bangladesh

This study was undertaken to determine the patterns of antimicrobial prescription by 64 Rural Medical Practitioners (RMPs) from Bangladesh. The antimicrobial dispensing procedures followed by the local retail drug sellers along with the purchasing capacities of the patients was also assessed. All antimicrobial agents were prescribed mainly on the patient's complaints, and all available antibiotics were prescribed in inappropriate doses and duration. In most cases, the RMPs initiated treatment with a parenteral form of antibiotic, and a different oral antibiotic usually followed. Parenteral streptomycin was used most frequently in short inadequate courses. Almost half of the antibiotics were sold without any prescriptions, and even ordinary people without any knowledge of medicine asked the drug seller for specific antibiotics. This unregulated prescribing and dispensing practice has the potential risk for the development and spread of antimicrobial resistance on a global scale.

Recent developments in cholera

Cholera continues to be an important public health problem among many poorer communities in Africa, Asia and South America, despite the bacteriology and epidemiology of the disease having been described over a century ago. Molecular techniques have enabled current researchers to gain new insights into pathogenicity, into the relationships between environmental and clinical strains, and into new strategies for vaccine development. The description of non-culturable 'dormant' strains in the environment and the effect of environmental factors on toxin gene regulation provide valuable clues to the ecology of the disease. Disease management continues to be based on urgent and appropriate rehydration, and recent community studies emphasize the need for effective local health services to provide this if case fatality rates are to remain low. While antimicrobial agents may play a role in case management and prophylaxis, the increasing prevalence of antimicrobial resistance must be addressed. New vaccine candidates, based on a molecular understanding of pathogenicity, provide scope for improved strategies for disease prevention, though the appropriate public health context for their use has not been determined. This review summarizes activities in these fields of cholera research and considers the continuing global problem of the disease.

Epidemiology and surveillance of antimicrobial resistance in the tropics

Antimicrobial resistance is threatening to undermine many of the health care improvements achieved in the tropics in the past 2 decades. While only limited data are available, there is evidence from most tropical areas of the spread of resistant bacterial strains in diseases from typhoid and bacillary dysentery to tuberculosis and, as in industrialized countries, multiply resistant hospital pathogens including methicillin-resistant Staphylococcus aureus (MRSA). Attempts to control the spread of resistant bacteria are limited by the lack of surveillance data at both the local and international level. For effective surveillance programmes to be implemented, the strengthening of laboratory services at district and national level, with a long-term commitment to resources, training and quality control, is essential.

Performance characteristics of the polymerase chain reaction assay to confirm clinical meningococcal disease

BACKGROUND

Confirmation of clinical meningococcal disease (MCD) is essential for management of patients, contacts, and outbreaks. Blood and CSF cultures, the traditional gold standard diagnostic tests, have been adversely affected by preadmission parenteral penicillin and fewer lumbar punctures. Rapid, reliable serogroup determination without the need to grow isolates could improve laboratory confirmation of MCD.

AIMS

To determine performance characteristics of the currently available meningococcal polymerase chain reaction (PCR) assays in a clinical setting.

METHODS

Prospective study of 319 children presenting with a suspected diagnosis of MCD (fever and a rash, or suspected bacterial meningitis) over a 16 month period.

RESULTS

A total of 166 (52% of all) children had clinical MCD: diagnosis was confirmed microbiologically in 119 (72%) of these. Performance characteristics (sensitivity, specificity, negative predictive value, positive predictive value) in confirmation of clinical MCD were respectively (95% confidence interval): blood culture 31% (24-38%), 100%, 57% (49-65%), 100%; blood PCR 47% (39-55%), 100%, 65% (58-73%), 100%; any test positive 72% (65-79%), 100%, 77% (70-84%), 100%.

CONCLUSIONS

Meningococcal DNA detection in blood or CSF by PCR is a useful method of diagnosis of MCD. PCR of peripheral blood performs better than blood culture. In a child with clinically suspected MCD, PCR assays, bacterial antigen tests, and oropharyngeal swabbing for meningococcal carriage should be performed in addition to blood or CSF culture, to improve case confirmation.

Communicable disease surveillance with limited resources: the scope to link human and veterinary programmes

Zoonoses are an important cause of human disease in much of Africa, but limitations in current diagnosis and surveillance strategies restrict the effectiveness of control and prevention programmes. Outbreaks of disease, ranging from Ebola virus infection to Rift Valley Fever, that have occurred recently in Africa have demonstrated the need for improved disease surveillance and monitoring. Strategies are suggested for co-ordinating human and animal disease surveillance programmes, at the district and regional level, to make more effective use of limited resources.

Increasing microbiological confirmation and changing epidemiology of meningococcal disease on Merseyside, England

OBJECTIVES

To determine, for the last 5 years in children on Merseyside with clinical meningococcal disease (MCD), the impact on diagnostic yield of newer bacteriologic methods; bacterial antigen detection (AD) and polymerase chain reaction (PCR).

METHODS

Prospective data collection at Royal Liverpool Children's Hospital over two epochs: 1 September 1992 to 30 April 1994 (epoch A, n = 126) and 17 November 1997 to 15 September 1998 (epoch B, n = 85).

RESULTS

Epoch A was compared with epoch B. Diagnosis was confirmed by detection of meningococci in 78 of 126 (61.9%) versus 64 of 85 (75.3%, P = 0.04), but with a significantly lower rate of positive blood and cerebrospinal fluid culture in the later epoch. The proportion of cases receiving penicillin pretreatment was unchanged at 32%, but the proportion undergoing lumbar puncture decreased significantly. Median ages were higher in epoch B: 1.7 years versus 2.49 years (P = 0.013, Mann-Whitney). There was a significant increase in the proportion of cases due to serogroup C (14/78 (18%) versus 30/64 (46.9%), P = 0.001).

CONCLUSIONS

Culture detection of meningococci from children with MCD has reduced, as less lumbar punctures are done. However, improved diagnosis by PCR and AD has increased microbiological confirmation overall. Serogroup C disease and the median age of cases continue to rise.

Emerging and reemerging infections in africa: the need for improved laboratory services and disease surveillance

Emerging and reemerging infections pose a serious public health threat to most countries of tropical Africa. In the past decade, epidemics of diseases including cholera, dysentery, meningitis, yellow fever and Ebola virus have resulted in significant morbidity and mortality. Improved laboratory services and disease surveillance systems are essential to monitor disease trends and to initiate public health action. The present situation of emerging and reemerging infections in Africa is described in this review, and strategies for improved disease surveillance and monitoring are discussed.

Antimicrobial resistance in the tropics

Bacterial resistance to antimicrobial agents is an increasing problem in many areas of the tropics. In most countries there is little information available to determine the patterns of resistance in different pathogens, nor are local data available to influence prescribing. This paper will review the development of antimicrobial resistance in the tropics, consider the current priority problems, and suggest strategies that may be taken to improve the surveillance of resistance.

Water quality and public health in northern Sudan: a study of rural and peri-urban communities

Access to adequate supplies of good quality drinking water continues to be limited among many rural and peri-urban communities in Africa, despite several decades of water improvement programmes. The present study investigated water quality at the source and point of consumption among rural and peri-urban communities in northern Sudan. Faecal coliform counts were determined by the membrane filtration technique and geometric mean counts compared in different seasons and among the different communities. Among nomadic pastoralists and riverine villages, both water sources and water stored for consumption had faecal coliform counts grossly in excess of WHO standards, with higher counts at the end of the rainy season. In the peri-urban community on the outskirts of Omdurman, while water quality from the distribution system had faecal coliform counts generally below 10 dl - 1, after storage, water was of considerably lower quality, with faecal coliform counts up to 1000 d1 - 1. The highest counts again occurred in the rainy season. Rates of diarrhoeal disease for Khartoum province were also greatest towards the end of the rainy season. The study has shown that poor quality water continues to be a major risk factor for public health in these communities.

Antimicrobial susceptibility of Shigella from a rural community in Bangladesh

Of the 63 Shigella strains isolated from stool cultures from 200 patients who attended a district hospital in Bangladesh with bloody diarrhoea, 37 (59%) were S. dysenteriae type 1, 25 (39%) were S. flexneri and only one (2%) was S. sonnei. Over half (54%) of the Shigella isolates came from children aged < 10 years. Most (89%) of the isolates of S. dysenteriae type 1 were resistant to ampicillin, cotrimoxazole, nalidixic acid, tetracycline and chloramphenicol. Although many (60%) of the isolates of S. flexneri were resistant to ampicillin and cotrimoxazole, only 4% of them were resistant to nalidixic acid. However, all of the S. dysenteriae and S. flexneri were sensitive to ciprofloxacin. The need for periodic monitoring to determine the resistance pattern in remote areas is emphasised.

Isolation and characterization of coliforms from glacial ice and water in Canada's High Arctic

Ellesmere Island is the northern most member of the Canadian Arctic Archipelago with over one-third of the land mass covered by ice. A joint services expedition to the island's Blue Mountains offered a unique opportunity for microbiological studies of resident bacteria in an environment uninhabited by man. Over 100 samples of water and ice were collected from stream, lake and glacier and the filtrate cultured under canvas. Bacterial growth was harvested onto swabs for transport back to the UK and 50 coliforms chosen at random for identification and antibiotic susceptibility testing. Most of the glacial strains were capsulated, pigmented and some over 2000 years old. Genera such as Serratia, Enterobacter, Klebsiella and Yersinia were found; speciation was inconclusive and some organisms remain unidentified. Ampicillin resistance was evident in 80% of water isolates as opposed to 30% of the glacial organisms, but the isolates were generally exquisitely susceptible to antibiotics. The facility for ampicillin resistance did not appear to be transferable. Plasmid DNA was found in 33% of the glacial organisms and over 50% of the water isolates. Similar profiles were identified within and apparently between species and required plasmid restriction analysis to help establish identity. Plasmid-free Serratia spp. were subjected to genomic fingerprinting. Indistinguishable patterns were found within sets of isolates both widely spaced by distance and collection date and it was postulated that coliforms able to survive an Arctic environment had spread extensively throughout the expedition area. In conclusion, this study contributes towards knowledge of naturally occurring antibiotic resistance, confirms the presence of plasmids and genotypic data provided evidence that potentially ancient organisms from glaciers can be cultured from water samples significantly distant.

Community-acquired notifiable infectious diseases in a pediatric hospital: effect on infection control work load

In a study of the impact of notifiable communicable disease admissions on infection control work load, we found notifiable disease cases to be responsible for less than 10% of admissions but 27% of infection control ward visits and to require extensive community liaison. Measures of work load based on nosocomial infections alone will underestimate infection control activity considerably.

Shigella infections

Shigella dysentery is a major public-health problem in many tropical areas. Despite improvements in water supplies and sanitation, it continues to be a disease of poor rural and urban communities and in populations affected by migration and crowding following disasters. Pathogenesis is due to colonic invasion, endotoxin, and, in Shigella dysenteriae 1, shiga toxin. As well as the local manifestations of dysentery, systemic complications include convulsions, haemolytic-uraemic syndrome, hyponatraemia and hypoglycaemia. The spread of shigella infection is most commonly person-person, although water and food-borne outbreaks have been reported. Since 1970, multiple antimicrobial resistance, particularly in Sh. dysenteriae 1, has complicated strategies for management. Multiply resistant strains have occurred in Latin America, Central Africa and southern and south-eastern Asia. No vaccines are currently available, and prevention and control will depend on public-health improvements and improved case management.

Tuberculous pericarditis in a child

A 14-year-old boy with tuberculous pericarditis and tamponade is described. Confirmation was by culture of pericardial aspirate. Though he did not have a cough, acid-fast bacilli were detected following induced sputum. Chest X-ray did not show evidence of pulmonary tuberculosis, but enlarged mediastinal nodes were detected by computerized tomography. He made an excellent response to anti-tuberculous chemotherapy and corticosteroids.

Water sources and environmental transmission of multiply resistant enteric bacteria in rural Bangladesh

The role of different water sources in the spread of multiply resistant enteric bacteria was investigated in rural Bangladesh. The prevalence of resistance to commonly used antimicrobial agents in the faecal flora of village children and the water quality and prevalence of resistance in village water sources were studied. Most of the children studied (81%) had multiply resistant faecal coliform bacteria, i.e. bacteria resistant to at least three antimicrobials. Although tubewells provided water with low faecal coliform counts, 62% of household storage pots contained water with moderate to high counts. Most of the storage pots (76%) and each of the river and pond sites tested contained multiply resistant isolates. Contamination of water within the household, and the widespread distribution of resistant coliforms in the environment, contribute to the high prevalence of multiply resistant enteric flora in the community. These findings are of importance in understanding the spread of multiply resistant enteric pathogens.

Community-acquired infections among children in an urban environment: a 2-year prospective study in Liverpool, U.K

Community-acquired infections are an important cause of admission of children to hospital. We have made a 2-year prospective study of 1,599 children admitted with infection to the Royal Liverpool Children's Hospital in order to determine the pattern of infections, their seasonal distribution and the role of the laboratory in isolating causative agents. Respiratory infections (32% cases) and gastroenteritis (28% cases) were the principal causes of admission. Of all admissions, 64% were children aged less than 1 year. Appropriate specimens were obtained and/or investigations made of 48% cases. Overall, a causative agent was determined in 21% cases. Individual pathogens showed marked seasonality. Respiratory syncytial virus, rotavirus and Shigella species were found more often in the winter months, while Salmonella species and adenovirus infections were most common in the summer. The results provide local data that is relevant to both public health and hospital planning. They also emphasise the need for continuing surveillance of community-acquired infections.

Cryptosporidium in Khartoum, Sudan

Diarrhoea caused by the protozoan parasite Cryptosporidium has been shown in several tropical countries to be an important health problem, particularly in children. Although infection is often associated with contact with animals, it may also occur through person to person transmission and via contaminated water or food. We have undertaken a cross sectional study to determine the prevalence of Cryptosporidium in children with diarrhoea and in their family contacts, and also investigated its occurrence in adult food handlers. Sixteen of 100 children with diarrhoea and none of the controls, were positive for Cryptosporidium. In addition, seven children had one or more sibs with diarrhoea who also excreted Cryptosporidium. None of the food handlers or asymptomatic children were positive. The results confirm earlier findings that Cryptosporidium is an important cause of diarrhoea in children in Sudan, and suggest that intrafamilial spread occurs.

Application of pyrolysis mass spectroscopy and SDS-PAGE in the study of the epidemiology of Pseudomonas cepacia in cystic fibrosis

Representative isolates of Pseudomonas cepacia from 15 cystic fibrosis (CF) patients attending the Respiratory Unit of Alder Hey Childrens' Hospital were investigated by SDS-PAGE of whole-cell polypeptides and by pyrolysis mass spectroscopy (PMS). SDS-PAGE was less discriminatory than PMS. Eleven isolates were indistinguishable by PMS and considered to represent re-isolates of an endemic strain; four isolates were distinct from this group, and from one another. P. cepacia was first isolated on the unit in July 1989 from a patient who had attended a UK selection meeting for a Canadian CF camp. A ward and outpatient segregation policy was introduced, but colonisation of further patients occurred. In August 1991, the Adult CF Association recommended that all social activities involving colonised patients should cease. This, and an increased awareness amongst older CF patients of the risks of person-to-person transmission, was associated with a marked decline in new cases. Social activity and hospital admissions were compared for colonised patients during the year before colonisation with P. cepacia, and matched patients who did not acquire the endemic strain. This showed a significantly higher attendance at CF social events for colonised patients, but no significant association between colonisation and hospital admission. These results are strong indirect evidence that transmission of P. cepacia occurs through social contact outside the hospital environment.

Genomic characterization of rotavirus strains obtained from hospitalized children with diarrhoea in Bangladesh

Faecal samples were obtained from 111 children hospitalized with acute watery gastroenteritis in a children's hospital in Bangladesh from January to December, 1989. Rotavirus was detected as the aetiologic agent in 35 (32%) of these patients. The electrophoretic pattern of ds-RNA extracted from the rotaviruses showed 11 different migration patterns (six short and five long), as well as some short and long mixed profiles. All four major G serotypes were identified by amplification of a segment of the gene for VP7 using the polymerase chain reaction. A specific serotype could be assigned in 32 (91%) cases. Serotypes G1-G4 accounted for 11%, 37%, 11%, and 23% of isolates respectively. Three (9%) mixed serotypes were identified by this method and were found to be mixtures of serotypes G1 and G4, G2 and G4, and G3 and G4.

Cholera

Although it is more than a century since the discovery of the vibrio bacillus, cholera remains one of the great epidemic diseases of the tropical world. The epidemiology of cholera is an interaction between the biological and ecological properties of Vibrio cholerae and the complex patterns of human behaviour in tropical environments. The seventh pandemic has spread through all areas of the tropics, and cholera has become endemic in many new areas. The view that cholera was primarily water borne and that humans were the only long-term reservoir has been challenged by the discovery that V. cholerae can survive, often in a dormant state, in aquatic environments. The recent appearance of V. cholerae 0139, a new serotype that causes a disease clinically and epidemiologically indistinct from cholera, has further complicated our understanding of this ancient disease. Developments in the molecular characterization of V. cholerae are providing new information to explain the genetic and epidemiological variations.

Effect of pH and CO2 on in vitro susceptibility of Pseudomonas cepacia to beta-lactams

Inhibition of Pseudomonas cepacia (but not Pseudomonas aeruginosa) by beta-lactams was decreased in 5% CO2 in air compared with air alone. The effect of CO2 and pH (range, 6.0 to 8.0) on beta-lactam susceptibility, beta-lactamase expression, and outer membrane proteins was studied in isolates recovered from the sputum of children with cystic fibrosis. Incubation in 5% CO2 decreased the activity of piperacillin, piperacillin/tazobactam, and ceftazidime, although isolates were still clinically sensitive (minimum inhibitory concentrations < 16 mg/L). Cefpirome activity was markedly decreased from a minimum inhibitory concentration of 2.0 to greater than 64 mg/L. On highly buffered 3-(N-morpholino)-propane sulfonic acid media, beta-lactam susceptibility was eliminated at pH greater 7.5. A 2- to 13-fold increase in beta-lactamase activity was demonstrated after growth in 5% CO2 compared with basal aerobic levels for 13 of 15 clinical isolates. beta-Lactamase activity did not vary significantly with pH. Addition of imipenem to media (2.0 mg/L) resulted in hyperproduction of beta-lactamase (180-fold). Isoelectric points varied with cultural conditions, and all beta-lactamases detected were inhibited by clavulanate and tazobactam. Significant hydrolysis of piperacillin and ceftazidime could not be demonstrated. A 36-kD porin was present at all pH tested. Thus, our strains of Pseudomonas cepacia were markedly affected by cultural conditions not normally used in standardized susceptibility tests. However, such conditions may be encountered in the pathologically altered infected lung in cystic fibrosis.

A pseudo outbreak of tuberculosis

Three cases of suspected tuberculosis were diagnosed over a ten day period at an oncology unit. Case finding was carried out and six further cases were diagnosed. However, doubts were raised about these diagnoses and a review of the outbreak investigation was carried out. Investigation of laboratory procedures found that the 'outbreak' was likely to be due to a contaminated phenol red solution. This incident highlights the importance of a critical evaluation of outbreak investigations, and the need for close collaboration between clinicians, epidemiologists and laboratory staff.

The prevalence and genetics of resistance to commonly used antimicrobial agents in faecal Enterobacteriaceae from children in Bangladesh

The present study was undertaken to investigate the occurrence of antibiotic resistance in enteric flora in 64 children in rural Bangladesh over a 12-month period. The antibiotic resistance pattern of the isolates varied throughout the year and multiple resistance was highest during the post monsoon period. Seventy-three percent of children had isolates resistant to more than three antibiotics throughout the year. Resistance to streptomycin was highest (78%), followed closely by ampicillin (72%). Of 82 multiply resistant isolates, plasmid DNA was demonstrated in 75%. Plasmid sizes ranged between 3.7 and 110 MDa, the commonest plasmids were of 70, 98 and 110 MDa. Complete or partial resistance was transferred by conjugation from 52% of the isolates, most frequently by single plasmids. The commonest plasmid incompatibility group was F11-A (46%) followed by incompatibility group P (22%). Plasmids of molecular weight 98 MDa most often hybridized with F11-A probes and those of 110 MDa with H11 probes. Plasmids from 10 transconjugants were digested with restriction enzymes and digest patterns demonstrated the presence of common plasmids. The findings show that there is a diverse, and mobile, genetic pool of resistance genes in this rural community. This genetic reservoir is potentially transferable to enteric pathogens, with major implications for public health and diarrhoeal disease control.

A study of bacterial meningitis in Kumasi, Ghana

A prospective study of acute bacterial meningitis in infants and children in Kumasi, Ghana identified 69 cases by culture or antigen detection. Of these, 50.7% (n = 35) were S. pneumoniae, 34.8% (n = 24) N. meningitidis and 14.5% (n = 10) H. influenzae. The mortality for each pathogen was 36.4%, 17.4% and 30%, respectively, showing no significant difference. In pneumococcal meningitis, the most significant clinical factor associated with an increased mortality rate or subsequent neurological sequelae was a lowered level of consciousness at admission (chi 2 = 8.66, d.f. = 1, p = 0.003). Antibiotic susceptibilities were determined in the 40 positive isolates. Six cases of N. meningitidis and two of S. pneumoniae were penicillin-resistant, and there was a single case of chloramphenicol-resistant S. pneumoniae.

Epidemiology and infection in famine and disasters

Despite advances in health care in the tropics, and the inputs of international and voluntary organisations, famine and disaster continue to cause major devastation in many developing countries. In the aftermath of acute disasters such as earthquakes or cyclones and in chronic post-famine relief camps, mortality rates may be 20–30 times greater than those in ‘normal’ years [1]. The interaction of malnutrition, crowding, poor environmental sanitation, and changes in host parasite relationships due to migration or environmental change, result in communicable diseases playing a major role in excess morbidity and mortality.

Pathogenesis of colonization and infection in a neonatal surgical unit

Nosocomial infection with aerobic Gram-negative bacilli is a major cause of morbidity and mortality in neonates. Few prospective studies have been undertaken in neonatal surgical units to investigate colonization and infection rates and the pathogenesis of infection. We prospectively studied 40 infants admitted to a neonatal surgical unit. Ninety-eight percent became colonized in throat/intestine with aerobic Gram-negative bacilli. Thirty-five percent developed infections, with wound and surface infections predominant (61%). Ninety-one percent of infections were caused by Gram-negative bacilli or yeasts. Severe infections (septicemia, pneumonia, meningitis) occurred in 13% of infants. The mortality rate was 5%. In all infections, the pathogenesis was found to be endogenous, and in most, three stages were distinguishable. Neonates always acquired potentially pathogenic organisms in throat/intestine (stage 1) before colonization (stage 2) and infection (stage 3) of other systems occurred. Reduction of digestive tract colonization by these potentially pathogenic microorganisms by means of successful selective decontamination may therefore reduce subsequent infection.

Restriction endonuclease characterization of resistant plasmids in Enterobacteriaceae isolated from children in the Sudan

The investigation of plasmid similarity is an important component in the surveillance of antimicrobial resistance and in the detection of epidemic plasmids. The use of restriction endonucleases in the classification of transferable, multiply-resistant plasmids from faecal Enterobacteriaceae isolated at the Children's Emergency Hospital, Khartoum was investigated. Twenty-four transconjugant plasmids, coding for 11 different resistance patterns, each of molecular weight 62 MDa, were studied using four restriction enzymes; Pst I, EcoR I, Hind III and Ava II. Fifteen different digest profiles were obtained. Restriction profiles discriminated between plasmids with differing resistance patterns and demonstrated homology of plasmids with common resistance patterns. Restriction endonuclease digest patterns provide a potentially rapid and reproducible method of plasmid classification, that could contribute towards surveillance systems in tropical countries with a high prevalence of antimicrobial resistance.

A preliminary investigation of antibiotic resistance in Enterobacteriaceae isolated from children with diarrhoea from four developing countries

The prevalence of resistance to commonly used antibiotics was investigated in groups of children from four developing countries, Peru, Belize, Zaire and Sudan. Enterobacteriaceae spp. isolated from faeces of children with diarrhoea were tested for sensitivity to ampicillin, tetracycline, sulphonamide, trimethoprim, streptomycin and chloramphenicol. Overall, the highest prevalence of resistance was to sulphonamide (56% of children) and the lowest was to chloramphenicol (19% of children). For individual locations, isolates from Sudan had the highest prevalence of antibiotic resistance, 65% of the isolates being resistant to ampicillin, tetracycline, trimethoprim and streptomycin. Transfer of resistance was studied for some isolates using Escherichia coli Hb101 as recipient.

Occurrence of multiple antibiotic resistance and R plasmids in Enterobacteriaceae isolated from children in the Sudan

The prevalence of resistance to six commonly-used antimicrobial agents in faecal coliforms from children in Khartoum, Sudan was studied. A relatively high prevalence of resistance was found, ranging from 96% of children with isolates resistant to ampicillin to 70% of children with isolates resistant to chloramphenicol. Seventy-seven percent of children had isolates with high-level resistance to trimethoprim (MIC greater than 1000 micrograms/ml). Twenty-nine different resistance patterns were found. Thirty-nine percent of the children had isolates resistant to all six antibiotics studied, and 80% of children had isolates resistant to at least four. Transfer of resistance to each of the antimicrobials, in varying combinations, was demonstrated, but did not occur for all resistance patterns. Plasmid analysis showed plasmids ranging from 160 MDa to 2.8 MDa and isolates contained from one to five plasmids of different sizes. There were no consistent relationships between resistance pattern and plasmid profile, but multiple resistance transfer was mediated commonly by plasmids with a molecular weight of 62 MDa. The high prevalence of potentially transferable antibiotic resistance in gut commensals of children in the Sudan may be of importance in the management of enteric and other infections requiring antimicrobial treatment.