Invasive group B streptococcal infection in infants, Malawi

The microbial spectrum of neonatal sepsis in Uganda: recovery of culturable bacteria in mother-infant pairs

Neonatal sepsis in the developing world is incompletely characterized. We seek to characterize the microbial spectrum involved in sepsis and determine the role of maternal transmission by comparing organisms that can be cultured from septic newborn infants and their mothers. From 80 consecutive mother-infant pairs meeting clinical criteria for neonatal sepsis, we collected infant blood and spinal fluid, and maternal blood and vaginal specimens. Identifiable bacteria were recovered from the blood in 32.5% of infants, and from 2.5% of cerebrospinal fluid cultures, for a total of 35% recoverable putative causative agents. Bacteria recovered from vaginal specimens were not concordant with those recovered from infants. Similarly there was no concordance of bacteria recovered from blood and cerebrospinal fluid. We conclude that relying on traditional bacterial culture techniques does not adequately delineate the role of maternal versus environmental sources of neonatal sepsis in this setting. More sensitive molecular approaches will be needed to properly characterize the maternal and environmental microbial community involved in neonatal sepsis in such developing countries.

Preventing intensive care admissions for sepsis in tropical Africa (PICASTA): an extension of the international pediatric global sepsis initiative: an African perspective

BACKGROUND

The Global Sepsis Initiative recommends prevention of sepsis through immunizations, vitamins, breast feeding, and other important interventions. In our study, we consider a second set of proposals for preventing intensive care admissions for sepsis in tropical Africa, which have been specifically designed to further prevent ICU admissions for sepsis in the group A nation hospital setting.

OBJECTIVES

To reduce admissions with severe sepsis in an ICU of a group A nation through the identification of challenges leading to preventable, foreseeable, or nosocomial sepsis specific to our setting.

METHODS

Malawi is one of the poorest countries in the world. Lacking the ability to comply with standard sepsis treatment, we conducted over 4 years several studies, audits, and surveys to identify challenges leading to preventable pediatric sepsis in our setting. We developed a method to identify malnourished children through a "gatekeeper" in the theaters without any equipment, tried to implement the World Health Organization's Safe Surgery Campaign checklist, evaluated our educational courses for the districts to improve the quality of referrals, looked into the extreme fasting times discovered in our hospital, trained different cadres in the districts to deal with peripartal and posttraumatic sepsis, and identified the needs in human resources to deal with pediatric sepsis in our setting.

RESULTS

Six foci were identified as promising to work on in future. Focus 1: Preventing elective operations and procedures in malnourished children in the hospital and in the district: 134 of 145 nurses (92.4%) and even 25 of 31 African laymen (80.6%) were able to identify malnourished children with their own fingers. Focus 2: Preventing sepsis-related problems in emergencies through the implementation of the Safe Surgery Campaign checklist: only 100 of 689 forms (14.5%) were filled in due to challenges in ownership, communication responsibility, and time constraints. Focus 3: Preventing sepsis through the reduction of unwise referrals: our courses toward this topic reached 82-100% satisfaction of the 391 participants for relevance, presentation applicability, content, and teaching technique. Focus 4: Preventing sepsis-related problems through reduction of excessive fasting times in our hospital: necessity for action was documented by a mean fasting time of 10.2 hours (SD, 4.4 hr). Focus 5: Concentration on two extremely sepsis-relevant health challenges for children in Malawian districts, trauma and peripartal complications: numbers after our courses in the trained two districts showed a reduction in the maternal mortality rate (from 150.3 to 55 and 234.2 to 75.2), an inconclusive result for posttraumatic deaths and the identification of 44 future instructors. Focus 6: Implementation of a Master in Medicine (anesthesia and intensive care) and improvement of training in anesthesia for all cadres resulted in the first five anesthetic registrars in training and enhanced numbers in all other cadres in anesthesia dealing in own responsibility with pediatric sepsis.

CONCLUSIONS

Every hospital can try to improve sepsis prevention on a local level by the Preventing Intensive Care Admissions for Sepsis in Tropical Africa approach. This will help support the promotion of the regionally adjusted Global Sepsis Initiative guidelines and the future global implementation of feasible bundles as a gold standard for resource-poor countries.

Susceptibility of bacterial etiological agents to commonly-used antimicrobial agents in children with sepsis at the Tamale Teaching Hospital

BACKGROUND

Bloodstream infections in neonates and infants are life-threatening emergencies. Identification of the common bacteria causing such infections and their susceptibility patterns will provide necessary information for timely intervention. This study is aimed at determining the susceptibilities of bacterial etiological agents to commonly-used antimicrobial agents for empirical treatment of suspected bacterial septicaemia in children.

METHODS

This is a hospital based retrospective analysis of blood cultures from infants to children up to 14 years of age with preliminary diagnosis of sepsis and admitted to the Neonatal Intensive Care Unit (NICU) and Paediatric Wards of the Teaching Hospital Tamale from July 2011 to January 2012.

RESULTS

Out of 331 blood specimens cultured, the prevalence of confirmed bacterial sepsis was 25.9% (86/331). Point prevalence for confirmed cases from NICU was 44.4% (28/63) and 21.6% (58/268) from the Paediatric ward. Gram positive cocci (GPC) were the predominant isolates with Coagulase positive (32.2%) and Coagulase-negative (28.7%) Staphylococci accounting for 60.9% of the total isolates. Gram negative rods (GNR) comprised 39.1% of all isolates with Klebsiella, E.coli and Salmonella being the most common organisms isolated. Klebsiella was the most frequent GNR from the NICU and Salmonella typhi was predominantly isolated from the paediatric ward. Acinetobacter showed 100.0% susceptibility to Ceftriaxone and Cefotaxime but was resistant (100.0%) to Ampicillin, Tetracycline and Cotrimoxazole. Escherichia coli and Klebsiella were 80.0% and 91.0% susceptible to Ceftriaxone and Cefotaxime respectively. Klebsiella species showed 8.3% susceptibility to Tetracycline but was resistant to Ampicillin and Cotrimoxazole. Escherichia coli showed 40.0% susceptibility to Ampicillin, Chloramphenicol and Cotrimoxazole; 20.0% susceptibility to Tetracycline and 80.0% susceptible to Gentamicin and Cefuroxime. Coagulase negative Staphylococci was susceptible to Gentamicin (72.0%) but Coagulase positive Staphylococci showed intermediate sensitivity to Gentamicin (42.9%).

CONCLUSION

Coagulase Negative, Coagulase Positive Staphylococci, Salmonella and Klebsiella were the aetiological agents of bloodstream infection among children at TTH. While gram-positive and gram-negative bacteria showed low susceptibility to Ampicillin, Tetracycline and Cotrimoxazole, the GNR were susceptible to Gentamicin and third-generation cephalosporins.

Distribution of pilus islands of group B streptococcus associated with maternal colonization and invasive disease in South Africa

Group B streptococcus (GBS) is a leading cause of neonatal sepsis. Sortase-dependent pilus-like structures have been identified on the surface of GBS, and have been found to be important in the adhesion and attachment of GBS to host cells. Three pilus island alleles, PI-1, PI-2a and PI-2b, have been described, and their proteins are being explored as vaccine candidates. The pilus islands from 541 colonization isolates and 284 invasive isolates were characterized by PCR. All isolates carried at least one pilus island, and they were identified alone or in combinations at the following overall frequencies: PI-2a, 29.8 %; PI-2b, 0.2 %; PI-1+PI-2a, 24.8 %; and PI-1+PI-2b, 45.1 %. A combination of PI-1+PI-2a (28.7 vs 17.6 %) was more common among colonizing compared with invasive isolates. Conversely, a combination of PI-1+PI-2b (37.2 vs 60.2 %) was more frequently associated with invasive disease compared to colonization. There was a strong association between pilus islands when adjusted for serotype distribution, PI-2a was identified in 92.6 % of colonizing and 90.0 % of invasive serotype Ia isolates, whereas serotype III was associated with co-expression of a PI-1 and PI-2b among 84.6 % of colonizing and 96.5 % of invasive isolates. Based on this homogeneity of pilus island distribution, a pilus-based vaccine developed for Europe and the USA will have similar coverage in South Africa.

A systematic review of the burden of neonatal mortality and morbidity in the ASEAN Region

Neonatal morbidity and mortality are major global public health challenges representing an increasing proportion of overall under-5 child mortality, with the vast majority of neonatal deaths occurring in resource-limited settings. In the Association of Southeast Asian Nations (ASEAN) region, it is estimated that approximately 200 000 neonatal deaths occur annually with reported estimates of the neonatal mortality rate ranging from 1 to over 30 per 1000 live-births, depending on the setting. The aim of this study is to conduct a systematic review of published data on neonatal morbidity and mortality from the ASEAN region over the last 10 years. Very few published studies reporting neonatal morbidity and mortality in this region were found. Importantly, data are available from just a few countries, with an underrepresentation of the most resource-limited settings. The majority of the studies describing mortality and morbidity were retrospective surveys or focussed on a specific cause of neonatal morbidity. Studies included findings from a range of settings, from neonatal intensive care to community settings utilizing verbal autopsy. Therefore, comprehensive and prospective data are needed to inform priorities and potential interventions to improve neonatal care and reduce neonatal mortality in this region.

Group B streptococcal disease in infants aged younger than 3 months: systematic review and meta-analysis

BACKGROUND

Despite widespread use of intrapartum antibiotic prophylaxis, group B streptococcus remains a leading cause of morbidity and mortality in infants in Europe, the Americas, and Australia. However, estimates of disease burden in many countries outside of these regions is not available. We aimed to examine the current global burden of invasive disease and the serotype distribution of group B streptococcus isolates.

METHODS

We searched Medline, Embase, and Wholis databases for studies on invasive early-onset (day 0-6) and late-onset (day 7-89) group B streptococcal disease. Eligible studies were those that described incidence, deaths, or serotypes. We also reviewed reference lists and contacted experts to seek unpublished data and data missed by our search. Random effects meta-analysis was used to pool data.

FINDINGS

74 studies met the inclusion criteria; 56 studies reported incidence, 29 case fatality, and 19 serotype distribution. An additional search for studies that reported serotype distribution from Jan 1, 1980, yielded a total of 38 articles. Only five low-income countries were represented in the review and contributed 5% weight to the meta-analysis. 47 (69%) studies reported use of any intrapartum antibiotic prophylaxis. Substantial heterogeneity existed between studies. Mean incidence of group B streptococcus in infants aged 0-89 days was 0·53 per 1000 livebirths (95% CI 0·44-0·62) and the mean case fatality ratio was 9·6% (95% CI 7·5-11·8). Incidence of early-onset group B streptococcus (0·43 per 1000 livebirths [95% CI 0·37-0·49]) and case fatality (12·1%, [6·2-18·3]) were two-times higher than late-onset disease. Serotype III (48·9%) was the most frequently identified serotype in all regions with available data followed by serotypes Ia (22·9%), Ib (7·0%), II (6·2%), and V (9·1%). Studies that reported use of any intrapartum antibiotic prophylaxis were associated with lower incidence of early-onset group B streptococcus (0·23 per 1000 livebirths [95% CI 0·13-0·59]) than studies in which patients did not use prophylaxis (0·75 per 1000 livebirths [0·58-0·89]).

INTERPRETATION

More high-quality studies are needed to accurately estimate the global burden of group B streptococcus, especially in low-income countries. A conjugate vaccine incorporating five serotypes (Ia, Ib, II, III, V) could prevent most global group B streptococcal disease.

FUNDING

Child Epidemiology Reference Group (CHERG), WHO.

Group B streptococcal carriage, serotype distribution and antibiotic susceptibilities in pregnant women at the time of delivery in a refugee population on the Thai-Myanmar border

Background

Group B Streptococcus (GBS) is the leading cause of neonatal sepsis in the developed world. Little is known about its epidemiology in the developing world, where the majority of deaths from neonatal infections occur. Maternal carriage of GBS is a prerequisite for the development of early onset GBS neonatal sepsis but there is a paucity of carriage data published from the developing world, in particular South East Asia.

Methods

We undertook a cross sectional study over a 13 month period in a remote South East Asian setting on the Thai-Myanmar border. During labour, 549 mothers had a combined vaginal rectal swab taken for GBS culture. All swabs underwent both conventional culture as well as PCR for GBS detection. Cultured GBS isolates were serotyped by latex agglutination, those that were negative or had a weak positive reaction and those that were PCR positive but culture negative were additionally tested using multiplex PCR based on the detection of GBS capsular polysaccharide genes.

Results

The GBS carriage rate was 12.0% (95% CI: 9.4-15.0), with 8.6% positive by both culture and PCR and an additional 3.5% positive by PCR alone. Serotypes, Ia, Ib, II, III, IV, V, VI and VII were identified, with II the predominant serotype. All GBS isolates were susceptible to penicillin, ceftriaxone and vancomycin and 43/47 (91.5%) were susceptible to erythromycin and clindamycin.

Conclusions

GBS carriage is not uncommon in pregnant women living on the Thai-Myanmar border with a large range of serotypes represented.

Bacteraemia in Malawian neonates and young infants 2002-2007: a retrospective audit

OBJECTIVES

To assess the causes of bacteraemia in young infants and susceptibility to first-line antibiotics (benzylpenicillin plus gentamicin) at the Queen Elizabeth Central Hospital (QECH), Malawi during 2002-2007.

DESIGN

Retrospective analysis of demographic and microbiological data using laboratory records.

SETTING

QECH is Malawi's largest hospital with 7000 neonates admitted annually, 9% for septicaemia.

PATIENTS

All infants aged 60 days or less admitted to QECH that had a blood culture taken over the 6-year period.

MAIN OUTCOME MEASURES

6754 blood cultures were taken. 3323 organisms were isolated: one-third were pathogens, two-thirds contaminants. Gram-positive organisms (53%) were more common than gram-negatives (47%). Four organisms made up half of all pathogens: Staphylococcus aureus (15.3%), group B streptococci (13.5%), non-typhoidal salmonellae (12.6%) and Escherichia coli (10.5%). Apart from non-typhoidal salmonellae and Streptococcus pneumoniae, most organisms were more common in the first week of life than later. Overall, 28% of isolates during 2002-2007 were resistant to first-line antibiotic, higher than observed during 1996-2001 (22%). Penicillin susceptibility fluctuated while gram-negative resistance to gentamicin increased from 17% to 27% over the study period.

CONCLUSIONS

In the QECH, pathogens causing young infant sepsis are an unusual mix of organisms seen in both developed and developing countries. Resistance to first-line antibiotics is higher than observed in most studies. Ongoing monitoring is needed and clinical outcome data would aid interpretation of findings. A high proportion of blood cultures were contaminated with skin flora-improved training and supervision of phlebotomists are needed to improve the utility of taking blood cultures.

No evidence of infection with avian influenza viruses among US poultry workers in the Delmarva Peninsula, Maryland and Virginia, USA

Industrial poultry workers may be at elevated risk of avian influenza infection due to intense occupational contact with live poultry. Serum samples from poultry workers and community members in the Delmarva Peninsula, one of the densest regions of poultry production in the United States, were analyzed for antibodies to strains of five avian influenza subtypes using microneutralization assays. No evidence of infection was found, suggesting inefficient transmission to humans or the absence of virus in these premises. Continued serological surveillance of workers in industrial food animal facilities is necessary to prevent the transmission of influenza A viruses.

Neonatal group B streptococcal disease: from pathogenesis to preventive strategies

Streptococcus agalactiae, or group B streptococcus (GBS), remains the leading cause of neonatal sepsis and meningitis, as early-onset or late-onset diseases (EOD, LOD). Where consensus guidelines to detect and treat intrapartum women with GBS colonization have been widely adopted, incidence of neonatal EOD has dramatically declined. In response to both successful impacts on the incidence of GBS-EOD and analyses of missed opportunities, the first American guidelines for prevention issued in the 1990s have since been adapted in several stages to improve their efficacy. In some countries in Europe, nationwide guidelines, whether screening-based or risk-based, for the prevention of neonatal GBS diseases have also been issued and adopted, with the expected impact on incidence of GBS-EOD. In spite of universal screening, in spite of the great progress that has been made, GBS-EOD continues to occur and the GBS burden remains a significant public health issue. Continuous efforts to improve screening for GBS status continue to be important and may be able to take advantage of new rapid diagnostic technologies. The current screening-based strategy for prevention is highly effective but imperfect. Given the challenges, limitations and potential complications of maternal intrapartum prophylaxis, a new approach is still needed. Maternal immunization against GBS is an attractive alternative for the prevention of not only neonatal diseases but also stillbirths and maternal diseases. Vaccines against GBS may become the most effective and sustainable long-term preventive strategy.

Molecular epidemiology of group B streptococcal meningitis in children beyond the neonatal period from Angola

Streptococcus agalactiae is a major pathogen of neonates and immunocompromised adults. Prior studies have demonstrated that, beyond the neonatal period, S. agalactiae rarely causes invasive infections in children. However, during 2004-2005, S. agalactiae was the causative agent of 60 meningitis episodes in children aged 3 months to 12 years from Angola. To identify and study the specific causative genetic lineages of S. agalactiae childhood meningitis, which lack characterization to date, we conducted an extensive molecular analysis of the recovered isolates (n = 21). This constitutes what we believe to be the first molecular study of the population structure of invasive S. agalactiae isolates from Africa. A low genetic diversity was observed among the isolates, where the majority belonged to clonal complex (CC) 17 presenting the capsular subtype III-2 (86 % of cases) and marked by the intron group II GBSi1, which has previously been observed to be associated with neonatal hosts. The predominance of single-locus variants of sequence type (ST) 17 suggested the local diversification of this hypervirulent clone, which displayed novel alleles of the fbsB and sip virulence genes. The absence of the scpB-lmb region in two S. agalactiae isolates with the Ia/ST23 genotype is more typical of cattle than human isolates. Globally, these data provide novel information about the enhanced invasiveness of the CC17 genetic lineage in older children and suggest the local diversification of this clone, which may be related to the future emergence of a novel epidemic clone in Angola.

Serotype distribution and invasive potential of group B streptococcus isolates causing disease in infants and colonizing maternal-newborn dyads

BACKGROUND

Serotype-specific polysaccharide based group B streptococcus (GBS) vaccines are being developed. An understanding of the serotype epidemiology associated with maternal colonization and invasive disease in infants is necessary to determine the potential coverage of serotype-specific GBS vaccines.

METHODS

Colonizing GBS isolates were identified by vaginal swabbing of mothers during active labor and from skin of their newborns post-delivery. Invasive GBS isolates from infants were identified through laboratory-based surveillance. GBS serotyping was done by latex agglutination. Serologically non-typeable isolates were typed by a serotype-specific PCR method. The invasive potential of GBS serotypes associated with sepsis within seven days of birth was evaluated in association to maternal colonizing serotypes.

RESULTS

GBS was identified in 289 (52.4%) newborns born to 551 women with GBS-vaginal colonization and from 113 (5.6%) newborns born to 2,010 mothers in whom GBS was not cultured from vaginal swabs. The serotype distribution among vaginal-colonizing isolates was as follows: III (37.3%), Ia (30.1%), and II (11.3%), V (10.2%), Ib (6.7%) and IV (3.7%). There were no significant differences in serotype distribution between vaginal and newborn colonizing isolates (P = 0.77). Serotype distribution of invasive GBS isolates were significantly different to that of colonizing isolates (P<0.0001). Serotype III was the most common invasive serotype in newborns less than 7 days (57.7%) and in infants 7 to 90 days of age (84.3%; P<0.001). Relative to serotype III, other serotypes showed reduced invasive potential: Ia (0.49; 95%CI 0.31-0.77), II (0.30; 95%CI 0.13-0.67) and V (0.38; 95%CI 0.17-0.83).

CONCLUSION

In South Africa, an anti-GBS vaccine including serotypes Ia, Ib and III has the potential of preventing 74.1%, 85.4% and 98.2% of GBS associated with maternal vaginal-colonization, invasive disease in neonates less than 7 days and invasive disease in infants between 7-90 days of age, respectively.

International perspective on early-onset neonatal sepsis

Infections are a major cause of neonatal death in developing countries. High-quality information on the burden of early-onset neonatal sepsis and sepsis-related deaths is limited in most of these settings. Simple preventive and treatment strategies have the potential to save many newborns from sepsis-related death. Implementation of public health programs targeting newborn health will assist attainment of Millennium Development Goals of reduction in child mortality.

Streptococcus agalactiae colonization and correlation with HIV-1 and HBV seroprevalence in pregnant women from Zimbabwe

OBJECTIVE

To estimate the frequency of coinfection of Streptococcus agalactiae or Group B streptococcus (GBS), hepatitis B virus (HBV) and HIV-1 in pregnant women and evaluate any association between them.

STUDY DESIGN

Three health centres from rural, rural-urban and urban communities were selected and at least 369 pregnant women had samples available for simultaneous analysis of GBS colonization rates, and HIV and HBV seroprevalence rates. Swabs were collected at two different stages in the course of pregnancy and at delivery to isolate GBS. Serum samples were collected at recruitment for analysis of standard HBV seromarkers and the presence of HIV-1. The odds ratio (95% CI) and chi(2) tests were used for analysis of the results at a level of significance set at <or=0.05.

RESULTS

Single infections with GBS, HBV and HIV-1 were found to be 35.7%, 3.3% and 20.1% respectively. The HIV-1 prevalence rate was 14.1%, 23.1% and 19.5% for the rural, rural-urban and urban communities respectively. The HBV prevalence rates were 3.3%, 3.0% and 3.7% for Chitsungo, Guruve and Harare respectively. There were no significant differences in HBV prevalence rates among the three communities. Simultaneous coinfection with GBS, HBV and HIV-1 was registered in only one (0.3%) of the women. The prevalence of coinfection with GBS/HBV, GBS/HIV-1 and HBV/HIV-1 was 0.5%, 9.2% and 0.8% respectively. The prevalence rate of GBS/HIV-1 coinfection was significantly higher in the rural-urban than the two other communities (p<0.001).

CONCLUSIONS

There was a high prevalence of single infections with GBS and HIV-1 but a lower HBV prevalence among pregnant women studied compared to other studies in Zimbabwe. Coinfection with GBS/HIV-1 was more common than GBS/HBV and HBV/HIV-1. Coinfection with HIV-1 and HBV did not differ between GBS colonized and GBS negative women. There was no difference in GBS colonization rate between HIV-1 positive and HIV-1 negative pregnant women.

Epidemiological update on swine influenza (H1N1) in pigs

The 2009 H1N1 pandemic has slowed down its spread after initial speed of transmission. The conventional swine influenza H1N1 virus (SIV) in pig populations worldwide needs to be differentiated from pandemic H1N1 influenza virus, however it is also essential to know about the exact role of pigs in the spread and mutations taking place in pig-to-pig transmission. The present paper reviews epidemiological features of classical SIV and its differentiation with pandemic influenza.

A review of published reports regarding zoonotic pathogen infection in veterinarians

OBJECTIVE

To identify published reports regarding zoonotic pathogen infection among veterinarians.

DESIGN

Literature review.

PROCEDURES

The PubMed electronic database of medical literature published between 1966 and November 2007 was searched. Clinical case reports and reports of outbreak investigations were also identified through searches of the literature outside of PubMed and searches of references listed in included articles. Reports eligible for inclusion included controlled and uncontrolled studies examining seroprevalence of animal pathogens in veterinarians, serosurveys involving veterinarians, and reports of zoonotic pathogen infections causing clinical illness.

RESULTS

66 relevant articles were identified. This included 44 seroepidemiologic studies (some examined > 1 pathogen), 12 case reports, 3 outbreak investigations, and 7 self-reported surveys (including 4 related to personal protective equipment use). Of the 44 seroepidemiologic studies, 37 (84%) identified an increased risk of zoonotic pathogen infection among veterinarians, and 7 (16%) identified no increased risk or a decreased risk. Surveys also documented that veterinarians often failed to use recommended personal protective equipment.

CONCLUSIONS AND CLINICAL RELEVANCE

Our review indicated that veterinarians had an increased risk of infection with a number of zoonotic pathogens. It also suggested that veterinarians may inadvertently serve as biological sentinels for emerging pathogens and could potentially spread zoonotic pathogens to their families, community members, and the animals for which they provide care. Professional and policy measures should be implemented to reduce the risk that veterinarians will become infected with, or transmit, zoonotic pathogens.

Maternal and early onset neonatal bacterial sepsis: burden and strategies for prevention in sub-Saharan Africa

Maternal and child health are high priorities for international development. Through a Review of published work, we show substantial gaps in current knowledge on incidence (cases per live births), aetiology, and risk factors for both maternal and early onset neonatal bacterial sepsis in sub-Saharan Africa. Although existing published data suggest that sepsis causes about 10% of all maternal deaths and 26% of neonatal deaths, these are likely to be considerable underestimates because of methodological limitations. Successful intervention strategies in resource-rich settings and early studies in sub-Saharan Africa suggest that the burden of maternal and early onset neonatal bacterial sepsis could be reduced through simple interventions, including antiseptic and antibiotic treatment. An effective way to expedite evidence to guide interventions and determine the incidence, aetiology, and risk factors for sepsis in sub-Saharan Africa would be through a multiarmed factorial intervention trial aimed at reducing both maternal and early onset neonatal bacterial sepsis in sub-Saharan Africa.

Triple-reassortant swine influenza A (H1) in humans in the United States, 2005-2009

BACKGROUND

Triple-reassortant swine influenza A (H1) viruses--containing genes from avian, human, and swine influenza viruses--emerged and became enzootic among pig herds in North America during the late 1990s.

METHODS

We report the clinical features of the first 11 sporadic cases of infection of humans with triple-reassortant swine influenza A (H1) viruses reported to the Centers for Disease Control and Prevention, occurring from December 2005 through February 2009, until just before the current epidemic of swine-origin influenza A (H1N1) among humans. These data were obtained from routine national influenza surveillance reports and from joint case investigations by public and animal health agencies.

RESULTS

The median age of the 11 patients was 10 years (range, 16 months to 48 years), and 4 had underlying health conditions. Nine of the patients had had exposure to pigs, five through direct contact and four through visits to a location where pigs were present but without contact. In another patient, human-to-human transmission was suspected. The range of the incubation period, from the last known exposure to the onset of symptoms, was 3 to 9 days. Among the 10 patients with known clinical symptoms, symptoms included fever (in 90%), cough (in 100%), headache (in 60%), and diarrhea (in 30%). Complete blood counts were available for four patients, revealing leukopenia in two, lymphopenia in one, and thrombocytopenia in another. Four patients were hospitalized, two of whom underwent invasive mechanical ventilation. Four patients received oseltamivir, and all 11 recovered from their illness.

CONCLUSIONS

From December 2005 until just before the current human epidemic of swine-origin influenza viruses, there was sporadic infection with triple-reassortant swine influenza A (H1) viruses in persons with exposure to pigs in the United States. Although all the patients recovered, severe illness of the lower respiratory tract and unusual influenza signs such as diarrhea were observed in some patients, including those who had been previously healthy.

Induction and termination of inflammatory signaling in group B streptococcal sepsis

SUMMARY

Group B streptococcus (GBS) is part of the normal genital and gastrointestinal flora in healthy humans. However, GBS is a major cause of sepsis and meningitis in newborn infants in the Western world and an important pathogen in many developing countries. The dissection of the host response to GBS may increase the general understanding of innate immunity in sepsis, because newborn infants lack a sufficient adaptive response. Inflammatory signal induction in macrophages by GBS seems largely preserved in newborn infants, as shown both in vitro and in vivo. The engagement of Toll-like receptor 2 (TLR2) by lipoproteins and a myeloid differentiation factor 88 (MyD88)--dependent pathway induced by GBS cell wall are both important in this context. TLR2 activation of microglia by GBS induces neuronal damage, which might account for the high morbidity of GBS meningitis. At the same time, TLR2 mediates activation-induced cell death (AICD), a process involved in the containment of inflammation. In newborn infants, AICD and anti-bacterial polymorphonuclear leukocyte activity appears to be compromised. Accordingly, neonatal aberrations in the pathogen-specific negative control of inflammatory signaling are likely to contribute to excessive inflammation and neurological sequelae in GBS sepsis and meningitis.

Industrial food animal production and global health risks: exploring the ecosystems and economics of avian influenza

Many emerging infectious diseases in human populations are associated with zoonotic origins. Attention has often focused on wild animal reservoirs, but most zoonotic pathogens of recent concern to human health either originate in, or are transferred to, human populations from domesticated animals raised for human consumption. Thus, the ecological context of emerging infectious disease comprises two overlapping ecosystems: the natural habitats and populations of wild animals, and the anthropogenically controlled habitats and populations of domesticated species. Intensive food animal production systems and their associated value chains dominate in developed countries and are increasingly important in developing countries. These systems are characterized by large numbers of animals being raised in confinement with high throughput and rapid turnover. Although not typically recognized as such, industrial food animal production generates unique ecosystems -- environments that may facilitate the evolution of zoonotic pathogens and their transmission to human populations. It is often assumed that confined food animal production reduces risks of emerging zoonotic diseases. This article provides evidence suggesting that these industrial systems may increase animal and public health risks unless there is recognition of the specific biosecurity and biocontainment challenges of the industrial model. Moreover, the economic drivers and constraints faced by the industry and its participants must be fully understood in order to inform preventative policy. In order to more effectively reduce zoonotic disease risk from industrial food animal production, private incentives for the implementation of biosecurity must align with public health interests.

Streptococcal Infections

The streptococci are a large heterogeneous group of gram-positive spherically shaped bacteria widely distributed in nature. They include some of the most important agents of human disease as well as members of the normal human flora. Some streptococci have been associated mainly with disease in animals, while others have been domesticated and used for the culture of buttermilk, yogurt, and certain cheeses. Those known to cause human disease comprise two broad categories: First are the pyogenic streptococci, including the familiar β-hemolytic streptococci and the pneumococcus. These organisms are not generally part of the normal flora but cause acute, often severe, infections in normal hosts. Second are the more diverse enteric and oral streptococci, which are nearly always part of the normal flora and which are more frequently associated with opportunistic infections.

Population structure of human isolates of Streptococcus agalactiae from Dakar and Bangui

Multilocus sequence types of 163 human Streptococcus agalactiae strains isolated in Bangui and Dakar were analyzed. We identified local specificities in the distribution of sequence types and capsular serotypes. However, the overall population structure is similar to that in the United States and Europe, suggesting that few specific clones colonize humans.

Bioinformatic insights into the biosynthesis of the Group B carbohydrate in Streptococcus agalactiae

Streptococcus agalactiae is a major human and animal pathogen, most notable as a cause of life-threatening disease in neonates. S. agalactiae is also called the Group B Streptococcus in reference to the diagnostically significant Lancefield Group B typing antigen. Although the structure of this complex carbohydrate antigen has been solved, little is known of its biosynthesis beyond the identification of a relevant locus in sequenced S. agalactiae genomes. Analysis of the sugar linkages present in the Group B carbohydrate (GBC) structure has allowed us to deduce the minimum enzymology required to complete its biosynthesis. Most of the enzymes required to complete this biosynthesis can be identified within the putative biosynthetic locus. Surprisingly, however, three crucial N-acetylglucosamine transferases and enzymes required for activated precursor synthesis are not apparently located in this locus. A model for GBC biosynthesis wherein the complete polymer is assembled at the cytoplasmic face of the plasma membrane before translocation to the cell surface is proposed. These analyses also suggest that GBC is the major teichoic acid-like polymer in the cell wall of S. agalactiae, whereas lipoteichoic acid is the dominant poly(glycerophosphate) antigen. Genomic analysis has allowed us to predict the pathway leading to the biosynthesis of GBC of S. agalactiae.

Recombinant group B Streptococcus alpha-like protein 3 is an effective immunogen and carrier protein

Conjugate vaccines against pathogens of multiple serotypes are optimized when all components induce functional antibody, resulting in broadened coverage. While most clinical studies of vaccines against group B Streptococcus (GBS) have evaluated conjugates composed of capsular polysaccharide (CPS) coupled to tetanus toxoid, conjugates prepared with GBS proteins as carriers have also been efficacious in animals. Here, we report that recombinant GBS alpha-like protein 3 (rAlp3) is both a strong immunogen and a viable carrier protein for type III CPS. The type III CPS-specific immunoglobulin G (IgG) titer rose from <100 to 64,000 among mice that received type III CPS coupled to rAlp3 (III-rAlp3) compared with an absence of a specific response among mice that received an uncoupled mixture. Most (94%) newborn pups born to III-rAlp-vaccinated dams survived challenge with viable type III GBS, compared with 43% survival among those born to dams that received the uncoupled mixture (P < 0.0001). A tricomponent conjugate of type III CPS, rAlp3, and a GBS recombinant beta C protein lacking its IgA binding site (III-rAlp3-rBCP(DeltaIgA)) provided protection against a serotype III strain and a serotype Ia strain bearing beta C protein. High-titered anti-rAlp3 rabbit serum opsonized Alp3-containing strains of two GBS serotypes (types V and VIII) and invasive type III strains bearing the cross-reactive Rib protein for in vitro killing by human peripheral blood leukocytes. Thus, the potential exists for the inclusion of rAlp3 in a GBS vaccine formulated to provide multiserotype coverage.